diff mbox series

[2/3] hwmon: Add support for SPD5118 compliant temperature sensors

Message ID 20240529205204.81208-3-linux@roeck-us.net (mailing list archive)
State Superseded
Headers show
Series hwmon: Add support for SPD5118 compliant temperature sensors | expand

Commit Message

Guenter Roeck May 29, 2024, 8:52 p.m. UTC
Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
sensors. Such sensors are typically found on DDR5 memory modules.

Cc: René Rebe <rene@exactcode.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
Tested on MAG B650 TOMAHAWK WIFI with CMH32GX5M2B6000Z30
(Corsair Venegance DDR5).

René: I included you as MODULE_AUTHOR since the patch is derived from
      your driver. Please let me know if you prefer not to be listed as
      author.

 Documentation/hwmon/index.rst   |   1 +
 Documentation/hwmon/spd5118.rst |  60 ++++
 drivers/hwmon/Kconfig           |  12 +
 drivers/hwmon/Makefile          |   1 +
 drivers/hwmon/spd5118.c         | 482 ++++++++++++++++++++++++++++++++
 5 files changed, 556 insertions(+)
 create mode 100644 Documentation/hwmon/spd5118.rst
 create mode 100644 drivers/hwmon/spd5118.c

Comments

Armin Wolf May 30, 2024, 8:08 a.m. UTC | #1
Am 29.05.24 um 22:52 schrieb Guenter Roeck:

> Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
> sensors. Such sensors are typically found on DDR5 memory modules.
>
> Cc: René Rebe <rene@exactcode.de>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> Tested on MAG B650 TOMAHAWK WIFI with CMH32GX5M2B6000Z30
> (Corsair Venegance DDR5).
>
> René: I included you as MODULE_AUTHOR since the patch is derived from
>        your driver. Please let me know if you prefer not to be listed as
>        author.
>
>   Documentation/hwmon/index.rst   |   1 +
>   Documentation/hwmon/spd5118.rst |  60 ++++
>   drivers/hwmon/Kconfig           |  12 +
>   drivers/hwmon/Makefile          |   1 +
>   drivers/hwmon/spd5118.c         | 482 ++++++++++++++++++++++++++++++++
>   5 files changed, 556 insertions(+)
>   create mode 100644 Documentation/hwmon/spd5118.rst
>   create mode 100644 drivers/hwmon/spd5118.c
>
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index 03d313af469a..6e7b8726b60c 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -215,6 +215,7 @@ Hardware Monitoring Kernel Drivers
>      smsc47m192
>      smsc47m1
>      sparx5-temp
> +   spd5118
>      stpddc60
>      surface_fan
>      sy7636a-hwmon
> diff --git a/Documentation/hwmon/spd5118.rst b/Documentation/hwmon/spd5118.rst
> new file mode 100644
> index 000000000000..67e990551a8a
> --- /dev/null
> +++ b/Documentation/hwmon/spd5118.rst
> @@ -0,0 +1,60 @@
> +.. SPDX-License-Identifier: GPL-2.0-or-later
> +
> +Kernel driver spd5118
> +=====================
> +
> +Supported chips:
> +
> +  * SPD5118 (JEDEC JESD300-5B.01) compliant temperature sensor chips
> +
> +    JEDEC standard download:
> +	https://www.jedec.org/standards-documents/docs/jesd300-5b01
> +	(account required)
> +
> +
> +    Prefix: 'spd5118'
> +
> +    Addresses scanned: I2C 0x50 - 0x57
> +
> +Author:
> +	Guenter Roeck <linux@roeck-us.net>
> +
> +
> +Description
> +-----------
> +
> +This driver implements support for SPD5118 (JEDEC JESD300-5B.01) compliant
> +temperature sensors, which are used on many DDR5 memory modules. Some systems
> +use the sensor to prevent memory overheating by automatically throttling
> +the memory controller.
> +
> +The driver auto-detects SPD5118 compliant chips, but can also be instantiated
> +using devicetree/firmware nodes.
> +
> +A SPD5118 compliant chip supports a single temperature sensor. Critical minimum,
> +minimum, maximum, and critical temperature can be configured. There are alarms
> +for low critical, low, high, and critical thresholds.
> +
> +
> +PEC configuration
> +-----------------
> +
> +If the I2C/SMBus controller supports PEC, it can be enabled or disabled using
> +the 'pec' sysfs attribute attached to the i2c device.
> +
> +
> +Hardware monitoring sysfs entries
> +---------------------------------
> +
> +======================= ==================================
> +temp1_input		Temperature (RO)
> +temp1_lcrit		Low critical high temperature (RW)
> +temp1_min		Minimum temperature (RW)
> +temp1_max		Maximum temperature (RW)
> +temp1_crit		Critical high temperature (RW)
> +
> +temp1_lcrit_alarm	Temperature low critical alarm
> +temp1_min_alarm		Temperature low alarm
> +temp1_max_alarm		Temperature high alarm
> +temp1_crit_alarm	Temperature critical alarm
> +======================= ===========================================
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 7f384a2494c9..111d05718b89 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -2182,6 +2182,18 @@ config SENSORS_INA3221
>   	  This driver can also be built as a module. If so, the module
>   	  will be called ina3221.
>
> +config SENSORS_SPD5118
> +	tristate "SPD5118 Compliant Temperature Sensors"
> +	depends on I2C
> +	select REGMAP_I2C
> +	help
> +	  If you say yes here you get support for SPD5118 (JEDEC JESD300-5B)
> +	  compliant temperature sensors. Such sensors are found on DDR5 memory
> +	  modules.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called spd5118.
> +
>   config SENSORS_TC74
>   	tristate "Microchip TC74"
>   	depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index e3f25475d1f0..07c593fae9a3 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -207,6 +207,7 @@ obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
>   obj-$(CONFIG_SENSORS_SMSC47M1)	+= smsc47m1.o
>   obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
>   obj-$(CONFIG_SENSORS_SPARX5)	+= sparx5-temp.o
> +obj-$(CONFIG_SENSORS_SPD51118)	+= spd5118.o

Hi,

thank you for working on this, i am currently testing the driver on my machine.
I already noticed the kconfig option is wrong, the correct one would be CONFIG_SENSORS_SPD5118.

Thanks,
Armin Wolf

>   obj-$(CONFIG_SENSORS_STTS751)	+= stts751.o
>   obj-$(CONFIG_SENSORS_SURFACE_FAN)+= surface_fan.o
>   obj-$(CONFIG_SENSORS_SY7636A)	+= sy7636a-hwmon.o
> diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c
> new file mode 100644
> index 000000000000..440503d09d13
> --- /dev/null
> +++ b/drivers/hwmon/spd5118.c
> @@ -0,0 +1,482 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Driver for Jedec 5118 compliant temperature sensors
> + *
> + * Derived from https://github.com/Steve-Tech/SPD5118-DKMS
> + * Originally from T/2 driver at https://t2sde.org/packages/linux
> + *	Copyright (c) 2023 René Rebe, ExactCODE GmbH; Germany.
> + *
> + * Copyright (c) 2024 Guenter Roeck
> + *
> + * Inspired by ee1004.c and jc42.c.
> + *
> + * SPD5118 compliant temperature sensors are typically used on DDR5
> + * memory modules.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/bits.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/hwmon.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <linux/units.h>
> +
> +/* Addresses to scan */
> +static const unsigned short normal_i2c[] = {
> +	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, I2C_CLIENT_END };
> +
> +/* SPD5118 registers. */
> +#define SPD5118_REG_TYPE		0x00	/* MR0:MR1 */
> +#define SPD5118_REG_REVISION		0x02	/* MR2 */
> +#define SPD5118_REG_VENDOR		0x03	/* MR3:MR4 */
> +#define SPD5118_REG_CAPABILITY		0x05	/* MR5 */
> +#define SPD5118_REG_I2C_LEGACY_MODE	0x0B	/* MR11 */
> +#define SPD5118_REG_TEMP_CLR		0x13	/* MR19 */
> +#define SPD5118_REG_ERROR_CLR		0x14	/* MR20 */
> +#define SPD5118_REG_TEMP_CONFIG		0x1A	/* MR26 */
> +#define SPD5118_REG_TEMP_MAX		0x1c	/* MR28:MR29 */
> +#define SPD5118_REG_TEMP_MIN		0x1e	/* MR30:MR31 */
> +#define SPD5118_REG_TEMP_CRIT		0x20	/* MR32:MR33 */
> +#define SPD5118_REG_TEMP_LCRIT		0x22	/* MR34:MR35 */
> +#define SPD5118_REG_TEMP		0x31	/* MR49:MR50 */
> +#define SPD5118_REG_TEMP_STATUS		0x33	/* MR51 */
> +
> +#define SPD5118_TEMP_STATUS_HIGH	BIT(0)
> +#define SPD5118_TEMP_STATUS_LOW		BIT(1)
> +#define SPD5118_TEMP_STATUS_CRIT	BIT(2)
> +#define SPD5118_TEMP_STATUS_LCRIT	BIT(3)
> +
> +#define SPD5118_CAP_TS_SUPPORT		BIT(1)	/* temperature sensor support */
> +
> +#define SPD5118_TS_DISABLE		BIT(0)	/* temperature sensor disable */
> +
> +/* Temperature unit in millicelsius */
> +#define SPD5118_TEMP_UNIT		(MILLIDEGREE_PER_DEGREE / 4)
> +/* Representable temperature range in millicelsius */
> +#define SPD5118_TEMP_RANGE_MIN		-256000
> +#define SPD5118_TEMP_RANGE_MAX		255750
> +
> +static int spd5118_temp_from_reg(u16 reg)
> +{
> +	int temp = sign_extend32(reg >> 2, 10);
> +
> +	return temp * SPD5118_TEMP_UNIT;
> +}
> +
> +static u16 spd5118_temp_to_reg(long temp)
> +{
> +	temp = clamp_val(temp, SPD5118_TEMP_RANGE_MIN, SPD5118_TEMP_RANGE_MAX);
> +	return (DIV_ROUND_CLOSEST(temp, SPD5118_TEMP_UNIT) & 0x7ff) << 2;
> +}
> +
> +static int spd5118_read_temp(struct regmap *regmap, u32 attr, long *val)
> +{
> +	int reg, err;
> +	u8 regval[2];
> +	u16 temp;
> +
> +	switch (attr) {
> +	case hwmon_temp_input:
> +		reg = SPD5118_REG_TEMP;
> +		break;
> +	case hwmon_temp_max:
> +		reg = SPD5118_REG_TEMP_MAX;
> +		break;
> +	case hwmon_temp_min:
> +		reg = SPD5118_REG_TEMP_MIN;
> +		break;
> +	case hwmon_temp_crit:
> +		reg = SPD5118_REG_TEMP_CRIT;
> +		break;
> +	case hwmon_temp_lcrit:
> +		reg = SPD5118_REG_TEMP_LCRIT;
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	err = regmap_bulk_read(regmap, reg, regval, 2);
> +	if (err)
> +		return err;
> +
> +	temp = (regval[1] << 8) | regval[0];
> +
> +	*val = spd5118_temp_from_reg(temp);
> +	return 0;
> +}
> +
> +static int spd5118_read_alarm(struct regmap *regmap, u32 attr, long *val)
> +{
> +	unsigned int mask, regval;
> +	int err;
> +
> +	switch (attr) {
> +	case hwmon_temp_max_alarm:
> +		mask = SPD5118_TEMP_STATUS_HIGH;
> +		break;
> +	case hwmon_temp_min_alarm:
> +		mask = SPD5118_TEMP_STATUS_LOW;
> +		break;
> +	case hwmon_temp_crit_alarm:
> +		mask = SPD5118_TEMP_STATUS_CRIT;
> +		break;
> +	case hwmon_temp_lcrit_alarm:
> +		mask = SPD5118_TEMP_STATUS_LCRIT;
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	err = regmap_read(regmap, SPD5118_REG_TEMP_STATUS, &regval);
> +	if (err < 0)
> +		return err;
> +	*val = !!(regval & mask);
> +	if (*val)
> +		return regmap_write(regmap, SPD5118_REG_TEMP_CLR, mask);
> +	return 0;
> +}
> +
> +static int spd5118_read_enable(struct regmap *regmap, u32 attr, long *val)
> +{
> +	u32 regval;
> +	int err;
> +
> +	err = regmap_read(regmap, SPD5118_REG_TEMP_CONFIG, &regval);
> +	if (err < 0)
> +		return err;
> +	*val = !(regval & SPD5118_TS_DISABLE);
> +	return 0;
> +}
> +
> +static int spd5118_read(struct device *dev, enum hwmon_sensor_types type,
> +			u32 attr, int channel, long *val)
> +{
> +	struct regmap *regmap = dev_get_drvdata(dev);
> +
> +	if (type != hwmon_temp)
> +		return -EOPNOTSUPP;
> +
> +	switch (attr) {
> +	case hwmon_temp_input:
> +	case hwmon_temp_max:
> +	case hwmon_temp_min:
> +	case hwmon_temp_crit:
> +	case hwmon_temp_lcrit:
> +		return spd5118_read_temp(regmap, attr, val);
> +	case hwmon_temp_max_alarm:
> +	case hwmon_temp_min_alarm:
> +	case hwmon_temp_crit_alarm:
> +	case hwmon_temp_lcrit_alarm:
> +		return spd5118_read_alarm(regmap, attr, val);
> +	case hwmon_temp_enable:
> +		return spd5118_read_enable(regmap, attr, val);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static int spd5118_write_temp(struct regmap *regmap, u32 attr, long val)
> +{
> +	u8 regval[2];
> +	u16 temp;
> +	int reg;
> +
> +	switch (attr) {
> +	case hwmon_temp_max:
> +		reg = SPD5118_REG_TEMP_MAX;
> +		break;
> +	case hwmon_temp_min:
> +		reg = SPD5118_REG_TEMP_MIN;
> +		break;
> +	case hwmon_temp_crit:
> +		reg = SPD5118_REG_TEMP_CRIT;
> +		break;
> +	case hwmon_temp_lcrit:
> +		reg = SPD5118_REG_TEMP_LCRIT;
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	temp = spd5118_temp_to_reg(val);
> +	regval[0] = temp & 0xff;
> +	regval[1] = temp >> 8;
> +
> +	return regmap_bulk_write(regmap, reg, regval, 2);
> +}
> +
> +static int spd5118_write_enable(struct regmap *regmap, u32 attr, long val)
> +{
> +	if (val && val != 1)
> +		return -EINVAL;
> +
> +	return regmap_update_bits(regmap, SPD5118_REG_TEMP_CONFIG,
> +				  SPD5118_TS_DISABLE,
> +				  val ? 0 : SPD5118_TS_DISABLE);
> +}
> +
> +static int spd5118_temp_write(struct regmap *regmap, u32 attr, long val)
> +{
> +	switch (attr) {
> +	case hwmon_temp_max:
> +	case hwmon_temp_min:
> +	case hwmon_temp_crit:
> +	case hwmon_temp_lcrit:
> +		return spd5118_write_temp(regmap, attr, val);
> +	case hwmon_temp_enable:
> +		return spd5118_write_enable(regmap, attr, val);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static int spd5118_write(struct device *dev, enum hwmon_sensor_types type,
> +			 u32 attr, int channel, long val)
> +{
> +	struct regmap *regmap = dev_get_drvdata(dev);
> +
> +	switch (type) {
> +	case hwmon_temp:
> +		return spd5118_temp_write(regmap, attr, val);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static umode_t spd5118_is_visible(const void *_data, enum hwmon_sensor_types type,
> +				  u32 attr, int channel)
> +{
> +	if (type != hwmon_temp)
> +		return 0;
> +
> +	switch (attr) {
> +	case hwmon_temp_input:
> +		return 0444;
> +	case hwmon_temp_min:
> +	case hwmon_temp_max:
> +	case hwmon_temp_lcrit:
> +	case hwmon_temp_crit:
> +	case hwmon_temp_enable:
> +		return 0644;
> +	case hwmon_temp_min_alarm:
> +	case hwmon_temp_max_alarm:
> +	case hwmon_temp_crit_alarm:
> +	case hwmon_temp_lcrit_alarm:
> +		return 0444;
> +	default:
> +		return 0;
> +	}
> +}
> +
> +static inline bool spd5118_parity8(u8 w)
> +{
> +	w ^= w >> 4;
> +	return (0x6996 >> (w & 0xf)) & 1;
> +}
> +
> +/*
> + * Bank and vendor id are 8-bit fields with seven data bits and odd parity.
> + * Vendor IDs 0 and 0x7f are invalid.
> + * See Jedec standard JEP106BJ for details and a list of assigned vendor IDs.
> + */
> +static bool spd5118_vendor_valid(u8 bank, u8 id)
> +{
> +	if (!spd5118_parity8(bank) || !spd5118_parity8(id))
> +		return false;
> +
> +	id &= 0x7f;
> +	return id && id != 0x7f;
> +}
> +
> +/* Return 0 if detection is successful, -ENODEV otherwise */
> +static int spd5118_detect(struct i2c_client *client, struct i2c_board_info *info)
> +{
> +	struct i2c_adapter *adapter = client->adapter;
> +	int regval;
> +
> +	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
> +				     I2C_FUNC_SMBUS_WORD_DATA))
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_word_swapped(client, SPD5118_REG_TYPE);
> +	if (regval != 0x5118)
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_word_data(client, SPD5118_REG_VENDOR);
> +	if (regval < 0 || !spd5118_vendor_valid(regval & 0xff, regval >> 8))
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_CAPABILITY);
> +	if (regval < 0)
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_TEMP_CLR);
> +	if (regval)
> +		return -ENODEV;
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_ERROR_CLR);
> +	if (regval)
> +		return -ENODEV;
> +
> +	if (!(regval & SPD5118_CAP_TS_SUPPORT) || (regval & 0xfc))
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_REVISION);
> +	if (regval < 0 || (regval & 0xc1))
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_TEMP_CONFIG);
> +	if (regval < 0)
> +		return -ENODEV;
> +	if (regval & ~SPD5118_TS_DISABLE)
> +		return -ENODEV;
> +
> +	strscpy(info->type, "spd5118", I2C_NAME_SIZE);
> +	return 0;
> +}
> +
> +static const struct hwmon_channel_info *spd5118_info[] = {
> +	HWMON_CHANNEL_INFO(chip,
> +			   HWMON_C_REGISTER_TZ),
> +	HWMON_CHANNEL_INFO(temp,
> +			   HWMON_T_INPUT |
> +			   HWMON_T_LCRIT | HWMON_T_LCRIT_ALARM |
> +			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
> +			   HWMON_T_MAX | HWMON_T_MAX_ALARM |
> +			   HWMON_T_CRIT | HWMON_T_CRIT_ALARM |
> +			   HWMON_T_ENABLE),
> +	NULL
> +};
> +
> +static const struct hwmon_ops spd5118_hwmon_ops = {
> +	.is_visible = spd5118_is_visible,
> +	.read = spd5118_read,
> +	.write = spd5118_write,
> +};
> +
> +static const struct hwmon_chip_info spd5118_chip_info = {
> +	.ops = &spd5118_hwmon_ops,
> +	.info = spd5118_info,
> +};
> +
> +static bool spd5118_writeable_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case SPD5118_REG_TEMP_CLR:
> +	case SPD5118_REG_TEMP_CONFIG:
> +	case SPD5118_REG_TEMP_MAX:
> +	case SPD5118_REG_TEMP_MAX + 1:
> +	case SPD5118_REG_TEMP_MIN:
> +	case SPD5118_REG_TEMP_MIN + 1:
> +	case SPD5118_REG_TEMP_CRIT:
> +	case SPD5118_REG_TEMP_CRIT + 1:
> +	case SPD5118_REG_TEMP_LCRIT:
> +	case SPD5118_REG_TEMP_LCRIT + 1:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool spd5118_volatile_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case SPD5118_REG_TEMP_CLR:
> +	case SPD5118_REG_ERROR_CLR:
> +	case SPD5118_REG_TEMP:
> +	case SPD5118_REG_TEMP + 1:
> +	case SPD5118_REG_TEMP_STATUS:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static const struct regmap_config spd5118_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = SPD5118_REG_TEMP_STATUS,
> +	.writeable_reg = spd5118_writeable_reg,
> +	.volatile_reg = spd5118_volatile_reg,
> +	.cache_type = REGCACHE_MAPLE,
> +};
> +
> +static int spd5118_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	unsigned int regval, revision, vendor, bank;
> +	struct device *hwmon_dev;
> +	struct regmap *regmap;
> +	int err;
> +
> +	regmap = devm_regmap_init_i2c(client, &spd5118_regmap_config);
> +	if (IS_ERR(regmap))
> +		return dev_err_probe(dev, PTR_ERR(regmap), "regmap init failed\n");
> +
> +	err = regmap_read(regmap, SPD5118_REG_CAPABILITY, &regval);
> +	if (err)
> +		return err;
> +	if (!(regval & SPD5118_CAP_TS_SUPPORT))
> +		return -ENODEV;
> +
> +	err = regmap_read(regmap, SPD5118_REG_REVISION, &revision);
> +	if (err)
> +		return err;
> +
> +	err = regmap_read(regmap, SPD5118_REG_VENDOR, &bank);
> +	if (err)
> +		return err;
> +	err = regmap_read(regmap, SPD5118_REG_VENDOR + 1, &vendor);
> +	if (err)
> +		return err;
> +	if (!spd5118_vendor_valid(bank, vendor))
> +		return -ENODEV;
> +
> +	hwmon_dev = devm_hwmon_device_register_with_info(dev, "spd5118",
> +							 regmap, &spd5118_chip_info,
> +							 NULL);
> +	if (IS_ERR(hwmon_dev))
> +		return PTR_ERR(hwmon_dev);
> +
> +	/*
> +	 * From JESD300-5B
> +	 *   MR2 bits [5:4]: Major revision, 1..4
> +	 *   MR2 bits [3:1]: Minor revision, 0..8? Probably a typo, assume 1..8
> +	 */
> +	dev_info(dev, "DDR5 temperature sensor: vendor 0x%02x:0x%02x revision %d.%d\n",
> +		 bank & 0x7f, vendor, ((revision >> 4) & 0x03) + 1, ((revision >> 1) & 0x07) + 1);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id spd5118_id[] = {
> +	{ "spd5118", 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, spd5118_id);
> +
> +static const struct of_device_id spd5118_of_ids[] = {
> +	{ .compatible = "jedec,spd5118", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, spd5118_of_ids);
> +
> +static struct i2c_driver spd5118_driver = {
> +	.class		= I2C_CLASS_HWMON,
> +	.driver = {
> +		.name	= "spd5118",
> +		.of_match_table = spd5118_of_ids,
> +	},
> +	.probe		= spd5118_probe,
> +	.id_table	= spd5118_id,
> +	.detect		= spd5118_detect,
> +	.address_list	= normal_i2c,
> +};
> +
> +module_i2c_driver(spd5118_driver);
> +
> +MODULE_AUTHOR("René Rebe <rene@exactcode.de>");
> +MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
> +MODULE_DESCRIPTION("SPD 5118 driver");
> +MODULE_LICENSE("GPL");
Thomas Weißschuh May 30, 2024, 9:08 a.m. UTC | #2
On 2024-05-29 13:52:03+0000, Guenter Roeck wrote:
> Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
> sensors. Such sensors are typically found on DDR5 memory modules.
> 
> Cc: René Rebe <rene@exactcode.de>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---

<snip>

> +/* Return 0 if detection is successful, -ENODEV otherwise */
> +static int spd5118_detect(struct i2c_client *client, struct i2c_board_info *info)
> +{
> +	struct i2c_adapter *adapter = client->adapter;
> +	int regval;
> +
> +	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
> +				     I2C_FUNC_SMBUS_WORD_DATA))
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_word_swapped(client, SPD5118_REG_TYPE);
> +	if (regval != 0x5118)
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_word_data(client, SPD5118_REG_VENDOR);
> +	if (regval < 0 || !spd5118_vendor_valid(regval & 0xff, regval >> 8))
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_CAPABILITY);
> +	if (regval < 0)
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_TEMP_CLR);
> +	if (regval)
> +		return -ENODEV;
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_ERROR_CLR);
> +	if (regval)
> +		return -ENODEV;
> +
> +	if (!(regval & SPD5118_CAP_TS_SUPPORT) || (regval & 0xfc))
> +		return -ENODEV;

This breaks automatic detection for me.

I think the test should after the read of SPD5118_REG_CAPABILITY and
test that register, similar on how it is done in _probe().

> +
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_REVISION);
> +	if (regval < 0 || (regval & 0xc1))
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_TEMP_CONFIG);
> +	if (regval < 0)
> +		return -ENODEV;
> +	if (regval & ~SPD5118_TS_DISABLE)
> +		return -ENODEV;
> +
> +	strscpy(info->type, "spd5118", I2C_NAME_SIZE);
> +	return 0;
> +}

<snip>
Thomas Weißschuh May 30, 2024, 10:51 a.m. UTC | #3
On 2024-05-29 13:52:03+0000, Guenter Roeck wrote:
> Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
> sensors. Such sensors are typically found on DDR5 memory modules.
> 
> Cc: René Rebe <rene@exactcode.de>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> Tested on MAG B650 TOMAHAWK WIFI with CMH32GX5M2B6000Z30
> (Corsair Venegance DDR5).
> 
> René: I included you as MODULE_AUTHOR since the patch is derived from
>       your driver. Please let me know if you prefer not to be listed as
>       author.
> 
>  Documentation/hwmon/index.rst   |   1 +
>  Documentation/hwmon/spd5118.rst |  60 ++++
>  drivers/hwmon/Kconfig           |  12 +
>  drivers/hwmon/Makefile          |   1 +
>  drivers/hwmon/spd5118.c         | 482 ++++++++++++++++++++++++++++++++
>  5 files changed, 556 insertions(+)
>  create mode 100644 Documentation/hwmon/spd5118.rst
>  create mode 100644 drivers/hwmon/spd5118.c

With the Makefile and detect callback fixed:

Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Tested-by: Thomas Weißschuh <linux@weissschuh.net>
Guenter Roeck May 30, 2024, 1:23 p.m. UTC | #4
On 5/30/24 01:08, Armin Wolf wrote:
[ ... ]
>> +obj-$(CONFIG_SENSORS_SPD51118)    += spd5118.o
> 
> Hi,
> 
> thank you for working on this, i am currently testing the driver on my machine.
> I already noticed the kconfig option is wrong, the correct one would be CONFIG_SENSORS_SPD5118.
> 

Oops. Thanks for noticing!

Guenter
Guenter Roeck May 30, 2024, 1:27 p.m. UTC | #5
On 5/30/24 02:08, Thomas Weißschuh wrote:
> On 2024-05-29 13:52:03+0000, Guenter Roeck wrote:
>> Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
>> sensors. Such sensors are typically found on DDR5 memory modules.
>>
>> Cc: René Rebe <rene@exactcode.de>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>> ---
> 
> <snip>
> 
>> +/* Return 0 if detection is successful, -ENODEV otherwise */
>> +static int spd5118_detect(struct i2c_client *client, struct i2c_board_info *info)
>> +{
>> +	struct i2c_adapter *adapter = client->adapter;
>> +	int regval;
>> +
>> +	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
>> +				     I2C_FUNC_SMBUS_WORD_DATA))
>> +		return -ENODEV;
>> +
>> +	regval = i2c_smbus_read_word_swapped(client, SPD5118_REG_TYPE);
>> +	if (regval != 0x5118)
>> +		return -ENODEV;
>> +
>> +	regval = i2c_smbus_read_word_data(client, SPD5118_REG_VENDOR);
>> +	if (regval < 0 || !spd5118_vendor_valid(regval & 0xff, regval >> 8))
>> +		return -ENODEV;
>> +
>> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_CAPABILITY);
>> +	if (regval < 0)
>> +		return -ENODEV;
>> +
>> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_TEMP_CLR);
>> +	if (regval)
>> +		return -ENODEV;
>> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_ERROR_CLR);
>> +	if (regval)
>> +		return -ENODEV;
>> +
>> +	if (!(regval & SPD5118_CAP_TS_SUPPORT) || (regval & 0xfc))
>> +		return -ENODEV;
> 
> This breaks automatic detection for me.
> 
> I think the test should after the read of SPD5118_REG_CAPABILITY and
> test that register, similar on how it is done in _probe().
> 

Yes, that got messed up when I added reading SPD5118_REG_TEMP_CLR and
SPD5118_REG_ERROR_CLR in the last minute. Thanks!

Thanks,
Guenter
Guenter Roeck May 30, 2024, 1:39 p.m. UTC | #6
On 5/30/24 06:23, Guenter Roeck wrote:
> On 5/30/24 01:08, Armin Wolf wrote:
> [ ... ]
>>> +obj-$(CONFIG_SENSORS_SPD51118)    += spd5118.o
>>
>> Hi,
>>
>> thank you for working on this, i am currently testing the driver on my machine.
>> I already noticed the kconfig option is wrong, the correct one would be CONFIG_SENSORS_SPD5118.
>>
> 
> Oops. Thanks for noticing!
> 

I fixed this up. I'll send v2 in a couple of days, probably early next week.

If it is not too much trouble, could you send me a register dump ?

Thanks,
Guenter
Guenter Roeck May 30, 2024, 1:47 p.m. UTC | #7
On 5/30/24 03:51, Thomas Weißschuh wrote:
> On 2024-05-29 13:52:03+0000, Guenter Roeck wrote:
>> Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
>> sensors. Such sensors are typically found on DDR5 memory modules.
>>
>> Cc: René Rebe <rene@exactcode.de>
>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>> ---
>> Tested on MAG B650 TOMAHAWK WIFI with CMH32GX5M2B6000Z30
>> (Corsair Venegance DDR5).
>>
>> René: I included you as MODULE_AUTHOR since the patch is derived from
>>        your driver. Please let me know if you prefer not to be listed as
>>        author.
>>
>>   Documentation/hwmon/index.rst   |   1 +
>>   Documentation/hwmon/spd5118.rst |  60 ++++
>>   drivers/hwmon/Kconfig           |  12 +
>>   drivers/hwmon/Makefile          |   1 +
>>   drivers/hwmon/spd5118.c         | 482 ++++++++++++++++++++++++++++++++
>>   5 files changed, 556 insertions(+)
>>   create mode 100644 Documentation/hwmon/spd5118.rst
>>   create mode 100644 drivers/hwmon/spd5118.c
> 
> With the Makefile and detect callback fixed:
> 
> Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
> Tested-by: Thomas Weißschuh <linux@weissschuh.net>

Thanks a lot for the feedback!

If it is not too much trouble, could you send me a register dump ?
The one I have is from Montage Technology M88SPD5118, and I'd like to get
a few more to improve my module test script.

Thanks,
Guenter
Thomas Weißschuh May 30, 2024, 1:57 p.m. UTC | #8
On 2024-05-30 06:47:17+0000, Guenter Roeck wrote:
> On 5/30/24 03:51, Thomas Weißschuh wrote:
> > On 2024-05-29 13:52:03+0000, Guenter Roeck wrote:
> > > Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
> > > sensors. Such sensors are typically found on DDR5 memory modules.
> > > 
> > > Cc: René Rebe <rene@exactcode.de>
> > > Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> > > ---
> > > Tested on MAG B650 TOMAHAWK WIFI with CMH32GX5M2B6000Z30
> > > (Corsair Venegance DDR5).
> > > 
> > > René: I included you as MODULE_AUTHOR since the patch is derived from
> > >        your driver. Please let me know if you prefer not to be listed as
> > >        author.
> > > 
> > >   Documentation/hwmon/index.rst   |   1 +
> > >   Documentation/hwmon/spd5118.rst |  60 ++++
> > >   drivers/hwmon/Kconfig           |  12 +
> > >   drivers/hwmon/Makefile          |   1 +
> > >   drivers/hwmon/spd5118.c         | 482 ++++++++++++++++++++++++++++++++
> > >   5 files changed, 556 insertions(+)
> > >   create mode 100644 Documentation/hwmon/spd5118.rst
> > >   create mode 100644 drivers/hwmon/spd5118.c
> > 
> > With the Makefile and detect callback fixed:
> > 
> > Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
> > Tested-by: Thomas Weißschuh <linux@weissschuh.net>
> 
> Thanks a lot for the feedback!
> 
> If it is not too much trouble, could you send me a register dump ?
> The one I have is from Montage Technology M88SPD5118, and I'd like to get
> a few more to improve my module test script.

From a Kingston KF556S40-32:

# i2cdump 20 0x50
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 51 18 0a 86 32 03 32 00 00 00 00 07 ff 3c 00 00    Q???2?2....?.<..
10: 00 00 00 00 00 00 00 00 00 00 00 00 70 03 00 00    ............p?..
20: 50 05 00 00 00 00 00 00 00 00 00 00 00 00 00 00    P?..............
30: 00 f0 01 00 00 00 00 00 00 00 00 00 00 00 00 00    .??.............
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
Guenter Roeck May 30, 2024, 2:07 p.m. UTC | #9
On 5/30/24 06:57, Thomas Weißschuh wrote:
> On 2024-05-30 06:47:17+0000, Guenter Roeck wrote:
>> On 5/30/24 03:51, Thomas Weißschuh wrote:
>>> On 2024-05-29 13:52:03+0000, Guenter Roeck wrote:
>>>> Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
>>>> sensors. Such sensors are typically found on DDR5 memory modules.
>>>>
>>>> Cc: René Rebe <rene@exactcode.de>
>>>> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
>>>> ---
>>>> Tested on MAG B650 TOMAHAWK WIFI with CMH32GX5M2B6000Z30
>>>> (Corsair Venegance DDR5).
>>>>
>>>> René: I included you as MODULE_AUTHOR since the patch is derived from
>>>>         your driver. Please let me know if you prefer not to be listed as
>>>>         author.
>>>>
>>>>    Documentation/hwmon/index.rst   |   1 +
>>>>    Documentation/hwmon/spd5118.rst |  60 ++++
>>>>    drivers/hwmon/Kconfig           |  12 +
>>>>    drivers/hwmon/Makefile          |   1 +
>>>>    drivers/hwmon/spd5118.c         | 482 ++++++++++++++++++++++++++++++++
>>>>    5 files changed, 556 insertions(+)
>>>>    create mode 100644 Documentation/hwmon/spd5118.rst
>>>>    create mode 100644 drivers/hwmon/spd5118.c
>>>
>>> With the Makefile and detect callback fixed:
>>>
>>> Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
>>> Tested-by: Thomas Weißschuh <linux@weissschuh.net>
>>
>> Thanks a lot for the feedback!
>>
>> If it is not too much trouble, could you send me a register dump ?
>> The one I have is from Montage Technology M88SPD5118, and I'd like to get
>> a few more to improve my module test script.
> 
>>From a Kingston KF556S40-32:
> 
> # i2cdump 20 0x50
>       0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
> 00: 51 18 0a 86 32 03 32 00 00 00 00 07 ff 3c 00 00    Q???2?2....?.<..
> 10: 00 00 00 00 00 00 00 00 00 00 00 00 70 03 00 00    ............p?..
> 20: 50 05 00 00 00 00 00 00 00 00 00 00 00 00 00 00    P?..............
> 30: 00 f0 01 00 00 00 00 00 00 00 00 00 00 00 00 00    .??.............
> 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> 50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> 60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> 70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> 80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> 90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

This is the same SPD hub chip (Montage Technology M88SPD5118)
as used on my Corsair DDRs. Interesting.

Thanks!
Guenter
Armin Wolf May 30, 2024, 4:45 p.m. UTC | #10
Am 30.05.24 um 15:39 schrieb Guenter Roeck:

> On 5/30/24 06:23, Guenter Roeck wrote:
>> On 5/30/24 01:08, Armin Wolf wrote:
>> [ ... ]
>>>> +obj-$(CONFIG_SENSORS_SPD51118)    += spd5118.o
>>>
>>> Hi,
>>>
>>> thank you for working on this, i am currently testing the driver on
>>> my machine.
>>> I already noticed the kconfig option is wrong, the correct one would
>>> be CONFIG_SENSORS_SPD5118.
>>>
>>
>> Oops. Thanks for noticing!
>>
>
> I fixed this up. I'll send v2 in a couple of days, probably early next
> week.
>
> If it is not too much trouble, could you send me a register dump ?
>
> Thanks,
> Guenter
>
>
# i2cdump 1 0x51
      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 51 18 0a 86 32 03 32 00 00 00 00 00 ff 3c 00 00    Q???2?2......<..
10: 00 00 00 00 00 00 00 00 00 00 00 00 70 03 00 00    ............p?..
20: 50 05 00 00 00 00 00 00 00 00 00 00 00 00 00 00    P?..............
30: 00 c0 01 00 00 00 00 00 00 00 00 00 00 00 00 00    .??.............
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
80: 30 10 12 02 04 00 40 42 00 00 00 00 b2 12 0d 00    0????.@B....???.
90: 00 00 00 00 a0 01 f2 03 7a 0d 00 00 00 00 80 3e    ....????z?....?>
a0: 80 3e 80 3e 00 7d 80 bb 30 75 27 01 a0 00 82 00    ?>?>.}??0u'??.?.
b0: 00 00 00 00 00 00 d4 00 00 00 d4 00 00 00 d4 00    ......?...?...?.
c0: 00 00 d4 00 00 00 88 13 08 88 13 08 20 4e 20 10    ..?...?????? N ?
d0: 27 10 1a 41 28 10 27 10 c4 09 04 4c 1d 0c 00 00    '??A(?'????L??..
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................

# i2cdump 1 0x53
      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
00: 51 18 0a 86 32 03 32 00 00 00 00 00 ff 3c 00 00    Q???2?2......<..
10: 00 00 00 00 00 00 00 00 00 00 00 00 70 03 00 00    ............p?..
20: 50 05 00 00 00 00 00 00 00 00 00 00 00 00 00 00    P?..............
30: 00 cc 01 00 00 00 00 00 00 00 00 00 00 00 00 00    .??.............
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
80: 30 10 12 02 04 00 40 42 00 00 00 00 b2 12 0d 00    0????.@B....???.
90: 00 00 00 00 a0 01 f2 03 7a 0d 00 00 00 00 80 3e    ....????z?....?>
a0: 80 3e 80 3e 00 7d 80 bb 30 75 27 01 a0 00 82 00    ?>?>.}??0u'??.?.
b0: 00 00 00 00 00 00 d4 00 00 00 d4 00 00 00 d4 00    ......?...?...?.
c0: 00 00 d4 00 00 00 88 13 08 88 13 08 20 4e 20 10    ..?...?????? N ?
d0: 27 10 1a 41 28 10 27 10 c4 09 04 4c 1d 0c 00 00    '??A(?'????L??..
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
Guenter Roeck May 30, 2024, 4:51 p.m. UTC | #11
Hi Armin,

On 5/30/24 09:45, Armin Wolf wrote:
[ ... ]
>>
> # i2cdump 1 0x51
>       0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f    0123456789abcdef
> 00: 51 18 0a 86 32 03 32 00 00 00 00 00 ff 3c 00 00    Q???2?2......<..
> 10: 00 00 00 00 00 00 00 00 00 00 00 00 70 03 00 00    ............p?..
> 20: 50 05 00 00 00 00 00 00 00 00 00 00 00 00 00 00    P?..............
> 30: 00 c0 01 00 00 00 00 00 00 00 00 00 00 00 00 00    .??.............
> 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> 50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> 60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> 70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> 80: 30 10 12 02 04 00 40 42 00 00 00 00 b2 12 0d 00    0????.@B....???.
> 90: 00 00 00 00 a0 01 f2 03 7a 0d 00 00 00 00 80 3e    ....????z?....?>
> a0: 80 3e 80 3e 00 7d 80 bb 30 75 27 01 a0 00 82 00    ?>?>.}??0u'??.?.
> b0: 00 00 00 00 00 00 d4 00 00 00 d4 00 00 00 d4 00    ......?...?...?.
> c0: 00 00 d4 00 00 00 88 13 08 88 13 08 20 4e 20 10    ..?...?????? N ?
> d0: 27 10 1a 41 28 10 27 10 c4 09 04 4c 1d 0c 00 00    '??A(?'????L??..
> e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00    ................
> 

Thanks a lot. This is again Montage Technology's M88SPD5118.
What is your DDR module vendor ?

Thanks,
Guenter
Armin Wolf May 30, 2024, 5:03 p.m. UTC | #12
Am 29.05.24 um 22:52 schrieb Guenter Roeck:

> Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
> sensors. Such sensors are typically found on DDR5 memory modules.
>
> Cc: René Rebe <rene@exactcode.de>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> Tested on MAG B650 TOMAHAWK WIFI with CMH32GX5M2B6000Z30
> (Corsair Venegance DDR5).
>
> René: I included you as MODULE_AUTHOR since the patch is derived from
>        your driver. Please let me know if you prefer not to be listed as
>        author.
>
>   Documentation/hwmon/index.rst   |   1 +
>   Documentation/hwmon/spd5118.rst |  60 ++++
>   drivers/hwmon/Kconfig           |  12 +
>   drivers/hwmon/Makefile          |   1 +
>   drivers/hwmon/spd5118.c         | 482 ++++++++++++++++++++++++++++++++
>   5 files changed, 556 insertions(+)
>   create mode 100644 Documentation/hwmon/spd5118.rst
>   create mode 100644 drivers/hwmon/spd5118.c
>
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index 03d313af469a..6e7b8726b60c 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -215,6 +215,7 @@ Hardware Monitoring Kernel Drivers
>      smsc47m192
>      smsc47m1
>      sparx5-temp
> +   spd5118
>      stpddc60
>      surface_fan
>      sy7636a-hwmon
> diff --git a/Documentation/hwmon/spd5118.rst b/Documentation/hwmon/spd5118.rst
> new file mode 100644
> index 000000000000..67e990551a8a
> --- /dev/null
> +++ b/Documentation/hwmon/spd5118.rst
> @@ -0,0 +1,60 @@
> +.. SPDX-License-Identifier: GPL-2.0-or-later
> +
> +Kernel driver spd5118
> +=====================
> +
> +Supported chips:
> +
> +  * SPD5118 (JEDEC JESD300-5B.01) compliant temperature sensor chips
> +
> +    JEDEC standard download:
> +	https://www.jedec.org/standards-documents/docs/jesd300-5b01
> +	(account required)
> +
> +
> +    Prefix: 'spd5118'
> +
> +    Addresses scanned: I2C 0x50 - 0x57
> +
> +Author:
> +	Guenter Roeck <linux@roeck-us.net>
> +
> +
> +Description
> +-----------
> +
> +This driver implements support for SPD5118 (JEDEC JESD300-5B.01) compliant
> +temperature sensors, which are used on many DDR5 memory modules. Some systems
> +use the sensor to prevent memory overheating by automatically throttling
> +the memory controller.
> +
> +The driver auto-detects SPD5118 compliant chips, but can also be instantiated
> +using devicetree/firmware nodes.
> +
> +A SPD5118 compliant chip supports a single temperature sensor. Critical minimum,
> +minimum, maximum, and critical temperature can be configured. There are alarms
> +for low critical, low, high, and critical thresholds.
> +
> +
> +PEC configuration
> +-----------------
> +
> +If the I2C/SMBus controller supports PEC, it can be enabled or disabled using
> +the 'pec' sysfs attribute attached to the i2c device.
> +

Hi,

the spd5118 only supports PEC when in i3c basic mode, so afaik we cannot use PEC here.

> +
> +Hardware monitoring sysfs entries
> +---------------------------------
> +
> +======================= ==================================
> +temp1_input		Temperature (RO)
> +temp1_lcrit		Low critical high temperature (RW)
> +temp1_min		Minimum temperature (RW)
> +temp1_max		Maximum temperature (RW)
> +temp1_crit		Critical high temperature (RW)
> +
> +temp1_lcrit_alarm	Temperature low critical alarm
> +temp1_min_alarm		Temperature low alarm
> +temp1_max_alarm		Temperature high alarm
> +temp1_crit_alarm	Temperature critical alarm

Maybe it would be a good idea to tell users that the alarm attributes are sticky.

> +======================= ===========================================
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 7f384a2494c9..111d05718b89 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -2182,6 +2182,18 @@ config SENSORS_INA3221
>   	  This driver can also be built as a module. If so, the module
>   	  will be called ina3221.
>
> +config SENSORS_SPD5118
> +	tristate "SPD5118 Compliant Temperature Sensors"
> +	depends on I2C
> +	select REGMAP_I2C
> +	help
> +	  If you say yes here you get support for SPD5118 (JEDEC JESD300-5B)
> +	  compliant temperature sensors. Such sensors are found on DDR5 memory
> +	  modules.
> +
> +	  This driver can also be built as a module. If so, the module
> +	  will be called spd5118.
> +
>   config SENSORS_TC74
>   	tristate "Microchip TC74"
>   	depends on I2C
> diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
> index e3f25475d1f0..07c593fae9a3 100644
> --- a/drivers/hwmon/Makefile
> +++ b/drivers/hwmon/Makefile
> @@ -207,6 +207,7 @@ obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
>   obj-$(CONFIG_SENSORS_SMSC47M1)	+= smsc47m1.o
>   obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
>   obj-$(CONFIG_SENSORS_SPARX5)	+= sparx5-temp.o
> +obj-$(CONFIG_SENSORS_SPD51118)	+= spd5118.o
>   obj-$(CONFIG_SENSORS_STTS751)	+= stts751.o
>   obj-$(CONFIG_SENSORS_SURFACE_FAN)+= surface_fan.o
>   obj-$(CONFIG_SENSORS_SY7636A)	+= sy7636a-hwmon.o
> diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c
> new file mode 100644
> index 000000000000..440503d09d13
> --- /dev/null
> +++ b/drivers/hwmon/spd5118.c
> @@ -0,0 +1,482 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Driver for Jedec 5118 compliant temperature sensors
> + *
> + * Derived from https://github.com/Steve-Tech/SPD5118-DKMS
> + * Originally from T/2 driver at https://t2sde.org/packages/linux
> + *	Copyright (c) 2023 René Rebe, ExactCODE GmbH; Germany.
> + *
> + * Copyright (c) 2024 Guenter Roeck
> + *
> + * Inspired by ee1004.c and jc42.c.
> + *
> + * SPD5118 compliant temperature sensors are typically used on DDR5
> + * memory modules.
> + */
> +
> +#include <linux/bitops.h>
> +#include <linux/bits.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/hwmon.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <linux/units.h>
> +
> +/* Addresses to scan */
> +static const unsigned short normal_i2c[] = {
> +	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, I2C_CLIENT_END };
> +
> +/* SPD5118 registers. */
> +#define SPD5118_REG_TYPE		0x00	/* MR0:MR1 */
> +#define SPD5118_REG_REVISION		0x02	/* MR2 */
> +#define SPD5118_REG_VENDOR		0x03	/* MR3:MR4 */
> +#define SPD5118_REG_CAPABILITY		0x05	/* MR5 */
> +#define SPD5118_REG_I2C_LEGACY_MODE	0x0B	/* MR11 */
> +#define SPD5118_REG_TEMP_CLR		0x13	/* MR19 */
> +#define SPD5118_REG_ERROR_CLR		0x14	/* MR20 */
> +#define SPD5118_REG_TEMP_CONFIG		0x1A	/* MR26 */
> +#define SPD5118_REG_TEMP_MAX		0x1c	/* MR28:MR29 */
> +#define SPD5118_REG_TEMP_MIN		0x1e	/* MR30:MR31 */
> +#define SPD5118_REG_TEMP_CRIT		0x20	/* MR32:MR33 */
> +#define SPD5118_REG_TEMP_LCRIT		0x22	/* MR34:MR35 */
> +#define SPD5118_REG_TEMP		0x31	/* MR49:MR50 */
> +#define SPD5118_REG_TEMP_STATUS		0x33	/* MR51 */
> +
> +#define SPD5118_TEMP_STATUS_HIGH	BIT(0)
> +#define SPD5118_TEMP_STATUS_LOW		BIT(1)
> +#define SPD5118_TEMP_STATUS_CRIT	BIT(2)
> +#define SPD5118_TEMP_STATUS_LCRIT	BIT(3)
> +
> +#define SPD5118_CAP_TS_SUPPORT		BIT(1)	/* temperature sensor support */
> +
> +#define SPD5118_TS_DISABLE		BIT(0)	/* temperature sensor disable */
> +
> +/* Temperature unit in millicelsius */
> +#define SPD5118_TEMP_UNIT		(MILLIDEGREE_PER_DEGREE / 4)
> +/* Representable temperature range in millicelsius */
> +#define SPD5118_TEMP_RANGE_MIN		-256000
> +#define SPD5118_TEMP_RANGE_MAX		255750
> +
> +static int spd5118_temp_from_reg(u16 reg)
> +{
> +	int temp = sign_extend32(reg >> 2, 10);
> +
> +	return temp * SPD5118_TEMP_UNIT;
> +}
> +
> +static u16 spd5118_temp_to_reg(long temp)
> +{
> +	temp = clamp_val(temp, SPD5118_TEMP_RANGE_MIN, SPD5118_TEMP_RANGE_MAX);
> +	return (DIV_ROUND_CLOSEST(temp, SPD5118_TEMP_UNIT) & 0x7ff) << 2;
> +}
> +
> +static int spd5118_read_temp(struct regmap *regmap, u32 attr, long *val)
> +{
> +	int reg, err;
> +	u8 regval[2];
> +	u16 temp;
> +
> +	switch (attr) {
> +	case hwmon_temp_input:
> +		reg = SPD5118_REG_TEMP;
> +		break;
> +	case hwmon_temp_max:
> +		reg = SPD5118_REG_TEMP_MAX;
> +		break;
> +	case hwmon_temp_min:
> +		reg = SPD5118_REG_TEMP_MIN;
> +		break;
> +	case hwmon_temp_crit:
> +		reg = SPD5118_REG_TEMP_CRIT;
> +		break;
> +	case hwmon_temp_lcrit:
> +		reg = SPD5118_REG_TEMP_LCRIT;
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	err = regmap_bulk_read(regmap, reg, regval, 2);
> +	if (err)
> +		return err;
> +
> +	temp = (regval[1] << 8) | regval[0];
> +
> +	*val = spd5118_temp_from_reg(temp);
> +	return 0;
> +}
> +
> +static int spd5118_read_alarm(struct regmap *regmap, u32 attr, long *val)
> +{
> +	unsigned int mask, regval;
> +	int err;
> +
> +	switch (attr) {
> +	case hwmon_temp_max_alarm:
> +		mask = SPD5118_TEMP_STATUS_HIGH;
> +		break;
> +	case hwmon_temp_min_alarm:
> +		mask = SPD5118_TEMP_STATUS_LOW;
> +		break;
> +	case hwmon_temp_crit_alarm:
> +		mask = SPD5118_TEMP_STATUS_CRIT;
> +		break;
> +	case hwmon_temp_lcrit_alarm:
> +		mask = SPD5118_TEMP_STATUS_LCRIT;
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	err = regmap_read(regmap, SPD5118_REG_TEMP_STATUS, &regval);
> +	if (err < 0)
> +		return err;
> +	*val = !!(regval & mask);
> +	if (*val)
> +		return regmap_write(regmap, SPD5118_REG_TEMP_CLR, mask);
> +	return 0;
> +}
> +
> +static int spd5118_read_enable(struct regmap *regmap, u32 attr, long *val)
> +{
> +	u32 regval;
> +	int err;
> +
> +	err = regmap_read(regmap, SPD5118_REG_TEMP_CONFIG, &regval);
> +	if (err < 0)
> +		return err;
> +	*val = !(regval & SPD5118_TS_DISABLE);
> +	return 0;
> +}
> +
> +static int spd5118_read(struct device *dev, enum hwmon_sensor_types type,
> +			u32 attr, int channel, long *val)
> +{
> +	struct regmap *regmap = dev_get_drvdata(dev);
> +
> +	if (type != hwmon_temp)
> +		return -EOPNOTSUPP;
> +
> +	switch (attr) {
> +	case hwmon_temp_input:
> +	case hwmon_temp_max:
> +	case hwmon_temp_min:
> +	case hwmon_temp_crit:
> +	case hwmon_temp_lcrit:
> +		return spd5118_read_temp(regmap, attr, val);
> +	case hwmon_temp_max_alarm:
> +	case hwmon_temp_min_alarm:
> +	case hwmon_temp_crit_alarm:
> +	case hwmon_temp_lcrit_alarm:
> +		return spd5118_read_alarm(regmap, attr, val);
> +	case hwmon_temp_enable:
> +		return spd5118_read_enable(regmap, attr, val);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static int spd5118_write_temp(struct regmap *regmap, u32 attr, long val)
> +{
> +	u8 regval[2];
> +	u16 temp;
> +	int reg;
> +
> +	switch (attr) {
> +	case hwmon_temp_max:
> +		reg = SPD5118_REG_TEMP_MAX;
> +		break;
> +	case hwmon_temp_min:
> +		reg = SPD5118_REG_TEMP_MIN;
> +		break;
> +	case hwmon_temp_crit:
> +		reg = SPD5118_REG_TEMP_CRIT;
> +		break;
> +	case hwmon_temp_lcrit:
> +		reg = SPD5118_REG_TEMP_LCRIT;
> +		break;
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +
> +	temp = spd5118_temp_to_reg(val);
> +	regval[0] = temp & 0xff;
> +	regval[1] = temp >> 8;
> +
> +	return regmap_bulk_write(regmap, reg, regval, 2);
> +}
> +
> +static int spd5118_write_enable(struct regmap *regmap, u32 attr, long val)
> +{
> +	if (val && val != 1)
> +		return -EINVAL;
> +
> +	return regmap_update_bits(regmap, SPD5118_REG_TEMP_CONFIG,
> +				  SPD5118_TS_DISABLE,
> +				  val ? 0 : SPD5118_TS_DISABLE);

The spd5118 spec says that we have to wait 10ms after enabling the sensors before
we start reading temperature values, maybe we need a delay + locking here?

> +}
> +
> +static int spd5118_temp_write(struct regmap *regmap, u32 attr, long val)
> +{
> +	switch (attr) {
> +	case hwmon_temp_max:
> +	case hwmon_temp_min:
> +	case hwmon_temp_crit:
> +	case hwmon_temp_lcrit:
> +		return spd5118_write_temp(regmap, attr, val);
> +	case hwmon_temp_enable:
> +		return spd5118_write_enable(regmap, attr, val);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static int spd5118_write(struct device *dev, enum hwmon_sensor_types type,
> +			 u32 attr, int channel, long val)
> +{
> +	struct regmap *regmap = dev_get_drvdata(dev);
> +
> +	switch (type) {
> +	case hwmon_temp:
> +		return spd5118_temp_write(regmap, attr, val);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +}
> +
> +static umode_t spd5118_is_visible(const void *_data, enum hwmon_sensor_types type,
> +				  u32 attr, int channel)
> +{
> +	if (type != hwmon_temp)
> +		return 0;
> +
> +	switch (attr) {
> +	case hwmon_temp_input:
> +		return 0444;
> +	case hwmon_temp_min:
> +	case hwmon_temp_max:
> +	case hwmon_temp_lcrit:
> +	case hwmon_temp_crit:
> +	case hwmon_temp_enable:
> +		return 0644;
> +	case hwmon_temp_min_alarm:
> +	case hwmon_temp_max_alarm:
> +	case hwmon_temp_crit_alarm:
> +	case hwmon_temp_lcrit_alarm:
> +		return 0444;
> +	default:
> +		return 0;
> +	}
> +}
> +
> +static inline bool spd5118_parity8(u8 w)
> +{
> +	w ^= w >> 4;
> +	return (0x6996 >> (w & 0xf)) & 1;
> +}
> +
> +/*
> + * Bank and vendor id are 8-bit fields with seven data bits and odd parity.
> + * Vendor IDs 0 and 0x7f are invalid.
> + * See Jedec standard JEP106BJ for details and a list of assigned vendor IDs.
> + */
> +static bool spd5118_vendor_valid(u8 bank, u8 id)
> +{
> +	if (!spd5118_parity8(bank) || !spd5118_parity8(id))
> +		return false;
> +
> +	id &= 0x7f;
> +	return id && id != 0x7f;
> +}
> +
> +/* Return 0 if detection is successful, -ENODEV otherwise */
> +static int spd5118_detect(struct i2c_client *client, struct i2c_board_info *info)
> +{
> +	struct i2c_adapter *adapter = client->adapter;
> +	int regval;
> +
> +	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
> +				     I2C_FUNC_SMBUS_WORD_DATA))
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_word_swapped(client, SPD5118_REG_TYPE);
> +	if (regval != 0x5118)
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_word_data(client, SPD5118_REG_VENDOR);
> +	if (regval < 0 || !spd5118_vendor_valid(regval & 0xff, regval >> 8))
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_CAPABILITY);
> +	if (regval < 0)
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_TEMP_CLR);
> +	if (regval)
> +		return -ENODEV;
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_ERROR_CLR);
> +	if (regval)
> +		return -ENODEV;
> +
> +	if (!(regval & SPD5118_CAP_TS_SUPPORT) || (regval & 0xfc))
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_REVISION);
> +	if (regval < 0 || (regval & 0xc1))
> +		return -ENODEV;
> +
> +	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_TEMP_CONFIG);
> +	if (regval < 0)
> +		return -ENODEV;
> +	if (regval & ~SPD5118_TS_DISABLE)
> +		return -ENODEV;
> +
> +	strscpy(info->type, "spd5118", I2C_NAME_SIZE);
> +	return 0;
> +}
> +
> +static const struct hwmon_channel_info *spd5118_info[] = {
> +	HWMON_CHANNEL_INFO(chip,
> +			   HWMON_C_REGISTER_TZ),
> +	HWMON_CHANNEL_INFO(temp,
> +			   HWMON_T_INPUT |
> +			   HWMON_T_LCRIT | HWMON_T_LCRIT_ALARM |
> +			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
> +			   HWMON_T_MAX | HWMON_T_MAX_ALARM |
> +			   HWMON_T_CRIT | HWMON_T_CRIT_ALARM |
> +			   HWMON_T_ENABLE),
> +	NULL
> +};
> +
> +static const struct hwmon_ops spd5118_hwmon_ops = {
> +	.is_visible = spd5118_is_visible,
> +	.read = spd5118_read,
> +	.write = spd5118_write,
> +};
> +
> +static const struct hwmon_chip_info spd5118_chip_info = {
> +	.ops = &spd5118_hwmon_ops,
> +	.info = spd5118_info,
> +};
> +
> +static bool spd5118_writeable_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case SPD5118_REG_TEMP_CLR:
> +	case SPD5118_REG_TEMP_CONFIG:
> +	case SPD5118_REG_TEMP_MAX:
> +	case SPD5118_REG_TEMP_MAX + 1:
> +	case SPD5118_REG_TEMP_MIN:
> +	case SPD5118_REG_TEMP_MIN + 1:
> +	case SPD5118_REG_TEMP_CRIT:
> +	case SPD5118_REG_TEMP_CRIT + 1:
> +	case SPD5118_REG_TEMP_LCRIT:
> +	case SPD5118_REG_TEMP_LCRIT + 1:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static bool spd5118_volatile_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case SPD5118_REG_TEMP_CLR:
> +	case SPD5118_REG_ERROR_CLR:
> +	case SPD5118_REG_TEMP:
> +	case SPD5118_REG_TEMP + 1:
> +	case SPD5118_REG_TEMP_STATUS:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static const struct regmap_config spd5118_regmap_config = {
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = SPD5118_REG_TEMP_STATUS,
> +	.writeable_reg = spd5118_writeable_reg,
> +	.volatile_reg = spd5118_volatile_reg,
> +	.cache_type = REGCACHE_MAPLE,
> +};
> +
> +static int spd5118_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	unsigned int regval, revision, vendor, bank;
> +	struct device *hwmon_dev;
> +	struct regmap *regmap;
> +	int err;
> +
> +	regmap = devm_regmap_init_i2c(client, &spd5118_regmap_config);
> +	if (IS_ERR(regmap))
> +		return dev_err_probe(dev, PTR_ERR(regmap), "regmap init failed\n");
> +
> +	err = regmap_read(regmap, SPD5118_REG_CAPABILITY, &regval);
> +	if (err)
> +		return err;
> +	if (!(regval & SPD5118_CAP_TS_SUPPORT))
> +		return -ENODEV;
> +
> +	err = regmap_read(regmap, SPD5118_REG_REVISION, &revision);
> +	if (err)
> +		return err;
> +
> +	err = regmap_read(regmap, SPD5118_REG_VENDOR, &bank);
> +	if (err)
> +		return err;
> +	err = regmap_read(regmap, SPD5118_REG_VENDOR + 1, &vendor);
> +	if (err)
> +		return err;
> +	if (!spd5118_vendor_valid(bank, vendor))
> +		return -ENODEV;
> +
> +	hwmon_dev = devm_hwmon_device_register_with_info(dev, "spd5118",
> +							 regmap, &spd5118_chip_info,
> +							 NULL);
> +	if (IS_ERR(hwmon_dev))
> +		return PTR_ERR(hwmon_dev);
> +
> +	/*
> +	 * From JESD300-5B
> +	 *   MR2 bits [5:4]: Major revision, 1..4
> +	 *   MR2 bits [3:1]: Minor revision, 0..8? Probably a typo, assume 1..8
> +	 */
> +	dev_info(dev, "DDR5 temperature sensor: vendor 0x%02x:0x%02x revision %d.%d\n",
> +		 bank & 0x7f, vendor, ((revision >> 4) & 0x03) + 1, ((revision >> 1) & 0x07) + 1);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id spd5118_id[] = {
> +	{ "spd5118", 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, spd5118_id);
> +
> +static const struct of_device_id spd5118_of_ids[] = {
> +	{ .compatible = "jedec,spd5118", },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, spd5118_of_ids);
> +
> +static struct i2c_driver spd5118_driver = {
> +	.class		= I2C_CLASS_HWMON,
> +	.driver = {
> +		.name	= "spd5118",
> +		.of_match_table = spd5118_of_ids,

The driver is missing suspend support, without it hibernation/S4 sleep will cause the
limit and config registers to be out of sync with the regmap cache.

Thanks,
Armin Wolf

> +	},
> +	.probe		= spd5118_probe,
> +	.id_table	= spd5118_id,
> +	.detect		= spd5118_detect,
> +	.address_list	= normal_i2c,
> +};
> +
> +module_i2c_driver(spd5118_driver);
> +
> +MODULE_AUTHOR("René Rebe <rene@exactcode.de>");
> +MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
> +MODULE_DESCRIPTION("SPD 5118 driver");
> +MODULE_LICENSE("GPL");
Armin Wolf May 30, 2024, 5:06 p.m. UTC | #13
Am 30.05.24 um 18:51 schrieb Guenter Roeck:

> Hi Armin,
>
> On 5/30/24 09:45, Armin Wolf wrote:
> [ ... ]
>>>
>> # i2cdump 1 0x51
>>       0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f 0123456789abcdef
>> 00: 51 18 0a 86 32 03 32 00 00 00 00 00 ff 3c 00 00 Q???2?2......<..
>> 10: 00 00 00 00 00 00 00 00 00 00 00 00 70 03 00 00 ............p?..
>> 20: 50 05 00 00 00 00 00 00 00 00 00 00 00 00 00 00 P?..............
>> 30: 00 c0 01 00 00 00 00 00 00 00 00 00 00 00 00 00 .??.............
>> 40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>> 50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>> 60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>> 70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>> 80: 30 10 12 02 04 00 40 42 00 00 00 00 b2 12 0d 00 0????.@B....???.
>> 90: 00 00 00 00 a0 01 f2 03 7a 0d 00 00 00 00 80 3e ....????z?....?>
>> a0: 80 3e 80 3e 00 7d 80 bb 30 75 27 01 a0 00 82 00 ?>?>.}??0u'??.?.
>> b0: 00 00 00 00 00 00 d4 00 00 00 d4 00 00 00 d4 00 ......?...?...?.
>> c0: 00 00 d4 00 00 00 88 13 08 88 13 08 20 4e 20 10 ..?...?????? N ?
>> d0: 27 10 1a 41 28 10 27 10 c4 09 04 4c 1d 0c 00 00 '??A(?'????L??..
>> e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>> f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>>
>
> Thanks a lot. This is again Montage Technology's M88SPD5118.
> What is your DDR module vendor ?
>
> Thanks,
> Guenter
>
Kingston Fury KF552C40BBK2-16, a 2x8GB DDR5 5200 kit.

Thanks,
Armin Wolf
Guenter Roeck May 30, 2024, 5:33 p.m. UTC | #14
On 5/30/24 10:03, Armin Wolf wrote:
> Am 29.05.24 um 22:52 schrieb Guenter Roeck:
> 
[ ... ]

>> +
>> +temp1_lcrit_alarm    Temperature low critical alarm
>> +temp1_min_alarm        Temperature low alarm
>> +temp1_max_alarm        Temperature high alarm
>> +temp1_crit_alarm    Temperature critical alarm
> 
> Maybe it would be a good idea to tell users that the alarm attributes are sticky.
> 

The driver auto-clears them after read, so they are only sticky in the sense
that they will remain active until read. This is quite common for hardware
monitoring devices. However, sure, I'll add a note.

[ ... ]

>> +static int spd5118_write_enable(struct regmap *regmap, u32 attr, long val)
>> +{
>> +    if (val && val != 1)
>> +        return -EINVAL;
>> +
>> +    return regmap_update_bits(regmap, SPD5118_REG_TEMP_CONFIG,
>> +                  SPD5118_TS_DISABLE,
>> +                  val ? 0 : SPD5118_TS_DISABLE);
> 
> The spd5118 spec says that we have to wait 10ms after enabling the sensors before
> we start reading temperature values, maybe we need a delay + locking here?
> 

I don't think that would add much if any value but a lot of complexity
for little gain. I find it acceptable that the sensor returns 0 for a few ms
after enabling it. Pretty much all chips have the same problem, so I am
really not concerned about it.

>> +
>> +static struct i2c_driver spd5118_driver = {
>> +    .class        = I2C_CLASS_HWMON,
>> +    .driver = {
>> +        .name    = "spd5118",
>> +        .of_match_table = spd5118_of_ids,
> 
> The driver is missing suspend support, without it hibernation/S4 sleep will cause the
> limit and config registers to be out of sync with the regmap cache.
> 

Good point. Do you have a means to test this if I add suspend support ?
I have not been able to figure out how to put my system into suspend.

Thanks,
Guenter
Guenter Roeck May 30, 2024, 5:36 p.m. UTC | #15
On 5/30/24 10:03, Armin Wolf wrote:
[ ... ]
>> +
>> +
>> +PEC configuration
>> +-----------------
>> +
>> +If the I2C/SMBus controller supports PEC, it can be enabled or disabled using
>> +the 'pec' sysfs attribute attached to the i2c device.
>> +
> 
> Hi,
> 
> the spd5118 only supports PEC when in i3c basic mode, so afaik we cannot use PEC here.
> 

Thanks for noticing. I misread the spec and associated the note with PAR_DIS,
not PEC_EN. I'll drop this and the PEC patch. Good that I kept it separate.

Thanks,
Guenter
Armin Wolf May 30, 2024, 5:41 p.m. UTC | #16
Am 30.05.24 um 19:33 schrieb Guenter Roeck:

> On 5/30/24 10:03, Armin Wolf wrote:
>> Am 29.05.24 um 22:52 schrieb Guenter Roeck:
>>
> [ ... ]
>
>>> +
>>> +temp1_lcrit_alarm    Temperature low critical alarm
>>> +temp1_min_alarm        Temperature low alarm
>>> +temp1_max_alarm        Temperature high alarm
>>> +temp1_crit_alarm    Temperature critical alarm
>>
>> Maybe it would be a good idea to tell users that the alarm attributes
>> are sticky.
>>
>
> The driver auto-clears them after read, so they are only sticky in the
> sense
> that they will remain active until read. This is quite common for
> hardware
> monitoring devices. However, sure, I'll add a note.
>
> [ ... ]
>
>>> +static int spd5118_write_enable(struct regmap *regmap, u32 attr,
>>> long val)
>>> +{
>>> +    if (val && val != 1)
>>> +        return -EINVAL;
>>> +
>>> +    return regmap_update_bits(regmap, SPD5118_REG_TEMP_CONFIG,
>>> +                  SPD5118_TS_DISABLE,
>>> +                  val ? 0 : SPD5118_TS_DISABLE);
>>
>> The spd5118 spec says that we have to wait 10ms after enabling the
>> sensors before
>> we start reading temperature values, maybe we need a delay + locking
>> here?
>>
>
> I don't think that would add much if any value but a lot of complexity
> for little gain. I find it acceptable that the sensor returns 0 for a
> few ms
> after enabling it. Pretty much all chips have the same problem, so I am
> really not concerned about it.
>
>>> +
>>> +static struct i2c_driver spd5118_driver = {
>>> +    .class        = I2C_CLASS_HWMON,
>>> +    .driver = {
>>> +        .name    = "spd5118",
>>> +        .of_match_table = spd5118_of_ids,
>>
>> The driver is missing suspend support, without it hibernation/S4
>> sleep will cause the
>> limit and config registers to be out of sync with the regmap cache.
>>
>
> Good point. Do you have a means to test this if I add suspend support ?
> I have not been able to figure out how to put my system into suspend.
>
> Thanks,
> Guenter
>
I think so, at least i can verify if S3 sleep works, but S4 sleep should work fine too.

Thanks,
Armin Wolf
Thomas Weißschuh May 30, 2024, 8:20 p.m. UTC | #17
On 2024-05-29 13:52:03+0000, Guenter Roeck wrote:
> Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
> sensors. Such sensors are typically found on DDR5 memory modules.

I can get the module to automatically probe with this change:

diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
index 97f338b123b1..8d9218f755d7 100644
--- a/drivers/i2c/i2c-smbus.c
+++ b/drivers/i2c/i2c-smbus.c
@@ -382,6 +386,10 @@ void i2c_register_spd(struct i2c_adapter *adap)
        case 0x1E:      /* LPDDR4 */
                name = "ee1004";
                break;
+       case 0x22:      /* DDR5 */
+       case 0x23:      /* LPDDR5 */
+               name = "spd5118";
+               break;
        default:
                dev_info(&adap->dev,
                         "Memory type 0x%02x not supported yet, not instantiating SPD\n",

(Credits go to Paul Menzel [0])

Maybe you can add that to your series.

To also work with my PIIX4 I2C bus, I also need:

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index fe6e8a1bb607..ff66e883b348 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -195,6 +195,7 @@ config I2C_ISMT
 config I2C_PIIX4
        tristate "Intel PIIX4 and compatible (ATI/AMD/Serverworks/Broadcom/SMSC)"
        depends on PCI && HAS_IOPORT
+       select I2C_SMBUS
        help
          If you say yes to this option, support will be included for the Intel
          PIIX4 family of mainboard I2C interfaces.  Specifically, the following
diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index 6a0392172b2f..f8d81f8c0cb3 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -29,6 +29,7 @@
 #include <linux/stddef.h>
 #include <linux/ioport.h>
 #include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
 #include <linux/slab.h>
 #include <linux/dmi.h>
 #include <linux/acpi.h>
@@ -982,6 +983,8 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
                return retval;
        }

+       i2c_register_spd(adap);
+
        *padap = adap;
        return 0;
 }

Though I guess it's not the right place to call i2c_register_sdp(),
I'll look at it some more and then submit it.

[0] https://lore.kernel.org/lkml/20240530183444.9312-2-pmenzel@molgen.mpg.de/
Guenter Roeck May 30, 2024, 8:46 p.m. UTC | #18
On 5/30/24 13:20, Thomas Weißschuh wrote:
> On 2024-05-29 13:52:03+0000, Guenter Roeck wrote:
>> Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
>> sensors. Such sensors are typically found on DDR5 memory modules.
> 
> I can get the module to automatically probe with this change:
> 
> diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
> index 97f338b123b1..8d9218f755d7 100644
> --- a/drivers/i2c/i2c-smbus.c
> +++ b/drivers/i2c/i2c-smbus.c
> @@ -382,6 +386,10 @@ void i2c_register_spd(struct i2c_adapter *adap)
>          case 0x1E:      /* LPDDR4 */
>                  name = "ee1004";
>                  break;
> +       case 0x22:      /* DDR5 */
> +       case 0x23:      /* LPDDR5 */
> +               name = "spd5118";
> +               break;
>          default:
>                  dev_info(&adap->dev,
>                           "Memory type 0x%02x not supported yet, not instantiating SPD\n",
> 
> (Credits go to Paul Menzel [0])
> 
> Maybe you can add that to your series.
> 

That is specifically for SPD (eeprom) support, which I didn't provide
in the driver. It does not register the equivalent jc42.4 temperature
sensor either. Given that, using the code to register a temperature
sensor seems inappropriate.

I didn't include accessing the SPD eeprom to the driver because I don't
have a use case. I don't mind adding it, though, if others think that it is
important.

> To also work with my PIIX4 I2C bus, I also need:
> 
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index fe6e8a1bb607..ff66e883b348 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -195,6 +195,7 @@ config I2C_ISMT
>   config I2C_PIIX4
>          tristate "Intel PIIX4 and compatible (ATI/AMD/Serverworks/Broadcom/SMSC)"
>          depends on PCI && HAS_IOPORT
> +       select I2C_SMBUS
>          help
>            If you say yes to this option, support will be included for the Intel
>            PIIX4 family of mainboard I2C interfaces.  Specifically, the following
> diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
> index 6a0392172b2f..f8d81f8c0cb3 100644
> --- a/drivers/i2c/busses/i2c-piix4.c
> +++ b/drivers/i2c/busses/i2c-piix4.c
> @@ -29,6 +29,7 @@
>   #include <linux/stddef.h>
>   #include <linux/ioport.h>
>   #include <linux/i2c.h>
> +#include <linux/i2c-smbus.h>
>   #include <linux/slab.h>
>   #include <linux/dmi.h>
>   #include <linux/acpi.h>
> @@ -982,6 +983,8 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
>                  return retval;
>          }
> 
> +       i2c_register_spd(adap);
> +
>          *padap = adap;
>          return 0;
>   }
> 
> Though I guess it's not the right place to call i2c_register_sdp(),
> I'll look at it some more and then submit it.
> 

Hmm, I didn't find a better place though.

Please copy me when you submit a patch; I can test it on an AMD system with
DDR4.

Thanks,
Guenter
Thomas Weißschuh May 30, 2024, 9:02 p.m. UTC | #19
On 2024-05-30 13:46:48+0000, Guenter Roeck wrote:
> On 5/30/24 13:20, Thomas Weißschuh wrote:
> > On 2024-05-29 13:52:03+0000, Guenter Roeck wrote:
> > > Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
> > > sensors. Such sensors are typically found on DDR5 memory modules.
> > 
> > I can get the module to automatically probe with this change:
> > 
> > diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
> > index 97f338b123b1..8d9218f755d7 100644
> > --- a/drivers/i2c/i2c-smbus.c
> > +++ b/drivers/i2c/i2c-smbus.c
> > @@ -382,6 +386,10 @@ void i2c_register_spd(struct i2c_adapter *adap)
> >          case 0x1E:      /* LPDDR4 */
> >                  name = "ee1004";
> >                  break;
> > +       case 0x22:      /* DDR5 */
> > +       case 0x23:      /* LPDDR5 */
> > +               name = "spd5118";
> > +               break;
> >          default:
> >                  dev_info(&adap->dev,
> >                           "Memory type 0x%02x not supported yet, not instantiating SPD\n",
> > 
> > (Credits go to Paul Menzel [0])
> > 
> > Maybe you can add that to your series.
> > 
> 
> That is specifically for SPD (eeprom) support, which I didn't provide
> in the driver. It does not register the equivalent jc42.4 temperature
> sensor either. Given that, using the code to register a temperature
> sensor seems inappropriate.

I see, I wasn't aware about the specifics of SPD.

It felt like a nice way to get automatic probing.
(I was wondering about that today before)

> I didn't include accessing the SPD eeprom to the driver because I don't
> have a use case. I don't mind adding it, though, if others think that it is
> important.

Wolfgang seems to think it's important:
https://lore.kernel.org/lkml/tdia472d4pow2osabef24y2ujkkquplfajxmmtk5pnxllsdxsz@wxzynz7llasr/

> > To also work with my PIIX4 I2C bus, I also need:
> > 
> > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> > index fe6e8a1bb607..ff66e883b348 100644
> > --- a/drivers/i2c/busses/Kconfig
> > +++ b/drivers/i2c/busses/Kconfig
> > @@ -195,6 +195,7 @@ config I2C_ISMT
> >   config I2C_PIIX4
> >          tristate "Intel PIIX4 and compatible (ATI/AMD/Serverworks/Broadcom/SMSC)"
> >          depends on PCI && HAS_IOPORT
> > +       select I2C_SMBUS
> >          help
> >            If you say yes to this option, support will be included for the Intel
> >            PIIX4 family of mainboard I2C interfaces.  Specifically, the following
> > diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
> > index 6a0392172b2f..f8d81f8c0cb3 100644
> > --- a/drivers/i2c/busses/i2c-piix4.c
> > +++ b/drivers/i2c/busses/i2c-piix4.c
> > @@ -29,6 +29,7 @@
> >   #include <linux/stddef.h>
> >   #include <linux/ioport.h>
> >   #include <linux/i2c.h>
> > +#include <linux/i2c-smbus.h>
> >   #include <linux/slab.h>
> >   #include <linux/dmi.h>
> >   #include <linux/acpi.h>
> > @@ -982,6 +983,8 @@ static int piix4_add_adapter(struct pci_dev *dev, unsigned short smba,
> >                  return retval;
> >          }
> > 
> > +       i2c_register_spd(adap);
> > +
> >          *padap = adap;
> >          return 0;
> >   }
> > 
> > Though I guess it's not the right place to call i2c_register_sdp(),
> > I'll look at it some more and then submit it.
> > 
> 
> Hmm, I didn't find a better place though.
> 
> Please copy me when you submit a patch; I can test it on an AMD system with
> DDR4.

Will do.


Thomas
Guenter Roeck May 30, 2024, 10:33 p.m. UTC | #20
On 5/30/24 14:02, Thomas Weißschuh wrote:
> On 2024-05-30 13:46:48+0000, Guenter Roeck wrote:
>> On 5/30/24 13:20, Thomas Weißschuh wrote:
>>> On 2024-05-29 13:52:03+0000, Guenter Roeck wrote:
>>>> Add support for SPD5118 (Jedec JESD300-5B.01) compliant temperature
>>>> sensors. Such sensors are typically found on DDR5 memory modules.
>>>
>>> I can get the module to automatically probe with this change:
>>>
>>> diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
>>> index 97f338b123b1..8d9218f755d7 100644
>>> --- a/drivers/i2c/i2c-smbus.c
>>> +++ b/drivers/i2c/i2c-smbus.c
>>> @@ -382,6 +386,10 @@ void i2c_register_spd(struct i2c_adapter *adap)
>>>           case 0x1E:      /* LPDDR4 */
>>>                   name = "ee1004";
>>>                   break;
>>> +       case 0x22:      /* DDR5 */
>>> +       case 0x23:      /* LPDDR5 */
>>> +               name = "spd5118";
>>> +               break;
>>>           default:
>>>                   dev_info(&adap->dev,
>>>                            "Memory type 0x%02x not supported yet, not instantiating SPD\n",
>>>
>>> (Credits go to Paul Menzel [0])
>>>
>>> Maybe you can add that to your series.
>>>
>>
>> That is specifically for SPD (eeprom) support, which I didn't provide
>> in the driver. It does not register the equivalent jc42.4 temperature
>> sensor either. Given that, using the code to register a temperature
>> sensor seems inappropriate.
> 
> I see, I wasn't aware about the specifics of SPD.
> 
> It felt like a nice way to get automatic probing.
> (I was wondering about that today before)
> 
>> I didn't include accessing the SPD eeprom to the driver because I don't
>> have a use case. I don't mind adding it, though, if others think that it is
>> important.
> 
> Wolfgang seems to think it's important:
> https://lore.kernel.org/lkml/tdia472d4pow2osabef24y2ujkkquplfajxmmtk5pnxllsdxsz@wxzynz7llasr/
> 

Ok, but that doesn't explain the reason. Wolfram, Paul, why do you
think this is needed ? Note that I am not opposed to adding spd
eeprom support, but I'd like to know why I am doing it before
I spend time on it.

Auto detection would be nice, though, because with that we could
drop support for the _detect function (which is kind of risky
on the i2c address range normally used for eeproms).

Thanks,
Guenter
Wolfram Sang May 31, 2024, 9:31 a.m. UTC | #21
Hi all,

> > Wolfgang seems to think it's important:

Wolfram, please.

> > https://lore.kernel.org/lkml/tdia472d4pow2osabef24y2ujkkquplfajxmmtk5pnxllsdxsz@wxzynz7llasr/
> > 
> 
> Ok, but that doesn't explain the reason. Wolfram, Paul, why do you
> think this is needed ? Note that I am not opposed to adding spd
> eeprom support, but I'd like to know why I am doing it before
> I spend time on it.

A working eeprom driver is needed to get 'decode-dimms' from the
i2c-tools package working. Jean reported that EEPROM access for DDR5 is
different from DDR4, so it needs a separate driver. And
i2c_register_spd() then needs to be updated to use the new driver for
DDR5.

Happy hacking,

   Wolfram
René Rebe May 31, 2024, 10:01 a.m. UTC | #22
Hi,

On May 31, 2024, at 11:31, Wolfram Sang <wsa+renesas@sang-engineering.com> wrote:
> 
> Hi all,
> 
>>> Wolfgang seems to think it's important:
> 
> Wolfram, please.
> 
>>> https://lore.kernel.org/lkml/tdia472d4pow2osabef24y2ujkkquplfajxmmtk5pnxllsdxsz@wxzynz7llasr/
>>> 
>> 
>> Ok, but that doesn't explain the reason. Wolfram, Paul, why do you
>> think this is needed ? Note that I am not opposed to adding spd
>> eeprom support, but I'd like to know why I am doing it before
>> I spend time on it.
> 
> A working eeprom driver is needed to get 'decode-dimms' from the
> i2c-tools package working. Jean reported that EEPROM access for DDR5 is
> different from DDR4, so it needs a separate driver. And
> i2c_register_spd() then needs to be updated to use the new driver for
> DDR5.

Well my original downstream driver already had eeprom access:

	https://svn.exactcode.de/t2/trunk/package/kernel/linux/spd-5118.patch

Note there are some surrounding -2, and parity patches around this patch.

Thanks,
	René

--
ExactCODE GmbH, Lietzenburger Str. 42, DE-10789 Berlin
http://exactcode.com | http://exactscan.com | http://ocrkit.com
Thomas Weißschuh May 31, 2024, 10:37 a.m. UTC | #23
On 2024-05-31 12:01:35+0000, René Rebe wrote:
> On May 31, 2024, at 11:31, Wolfram Sang <wsa+renesas@sang-engineering.com> wrote:
> >>> Wolfgang seems to think it's important:
> > 
> > Wolfram, please.

Sorry, Wolfram.

> > 
> >>> https://lore.kernel.org/lkml/tdia472d4pow2osabef24y2ujkkquplfajxmmtk5pnxllsdxsz@wxzynz7llasr/
> >>> 
> >> 
> >> Ok, but that doesn't explain the reason. Wolfram, Paul, why do you
> >> think this is needed ? Note that I am not opposed to adding spd
> >> eeprom support, but I'd like to know why I am doing it before
> >> I spend time on it.
> > 
> > A working eeprom driver is needed to get 'decode-dimms' from the
> > i2c-tools package working. Jean reported that EEPROM access for DDR5 is
> > different from DDR4, so it needs a separate driver. And
> > i2c_register_spd() then needs to be updated to use the new driver for
> > DDR5.
> 
> Well my original downstream driver already had eeprom access:
> 
> 	https://svn.exactcode.de/t2/trunk/package/kernel/linux/spd-5118.patch
> 
> Note there are some surrounding -2, and parity patches around this patch.

That would need to be rewritten to use the nvmem APIs though, I guess.
If nobody wants to do it, I'm volunteering.

Thomas
Guenter Roeck May 31, 2024, 1:14 p.m. UTC | #24
Hi René,

On 5/31/24 03:01, René Rebe wrote:
> Hi,
> 
> On May 31, 2024, at 11:31, Wolfram Sang <wsa+renesas@sang-engineering.com> wrote:
>>
>> Hi all,
>>
>>>> Wolfgang seems to think it's important:
>>
>> Wolfram, please.
>>
>>>> https://lore.kernel.org/lkml/tdia472d4pow2osabef24y2ujkkquplfajxmmtk5pnxllsdxsz@wxzynz7llasr/
>>>>
>>>
>>> Ok, but that doesn't explain the reason. Wolfram, Paul, why do you
>>> think this is needed ? Note that I am not opposed to adding spd
>>> eeprom support, but I'd like to know why I am doing it before
>>> I spend time on it.
>>
>> A working eeprom driver is needed to get 'decode-dimms' from the
>> i2c-tools package working. Jean reported that EEPROM access for DDR5 is
>> different from DDR4, so it needs a separate driver. And
>> i2c_register_spd() then needs to be updated to use the new driver for
>> DDR5.
> 
> Well my original downstream driver already had eeprom access:
> 
> 	https://svn.exactcode.de/t2/trunk/package/kernel/linux/spd-5118.patch
> 

Yes, but you didn't send it upstream, so I took it, fixed a couple of bugs,
dropped eeprom support since that is secondary for my use case as well as the
out-of-tree parity code, and submitted it. I'd be more than happy to let you
take over if you like.

Thanks,
Guenter
René Rebe May 31, 2024, 1:20 p.m. UTC | #25
Hi,

> On May 31, 2024, at 15:14, Guenter Roeck <linux@roeck-us.net> wrote:
> 
> Hi René,
> 
> On 5/31/24 03:01, René Rebe wrote:
>> Hi,
>> On May 31, 2024, at 11:31, Wolfram Sang <wsa+renesas@sang-engineering.com> wrote:
>>> 
>>> Hi all,
>>> 
>>>>> Wolfgang seems to think it's important:
>>> 
>>> Wolfram, please.
>>> 
>>>>> https://lore.kernel.org/lkml/tdia472d4pow2osabef24y2ujkkquplfajxmmtk5pnxllsdxsz@wxzynz7llasr/
>>>>> 
>>>> 
>>>> Ok, but that doesn't explain the reason. Wolfram, Paul, why do you
>>>> think this is needed ? Note that I am not opposed to adding spd
>>>> eeprom support, but I'd like to know why I am doing it before
>>>> I spend time on it.
>>> 
>>> A working eeprom driver is needed to get 'decode-dimms' from the
>>> i2c-tools package working. Jean reported that EEPROM access for DDR5 is
>>> different from DDR4, so it needs a separate driver. And
>>> i2c_register_spd() then needs to be updated to use the new driver for
>>> DDR5.
>> Well my original downstream driver already had eeprom access:
>> https://svn.exactcode.de/t2/trunk/package/kernel/linux/spd-5118.patch
> 
> Yes, but you didn't send it upstream, so I took it, fixed a couple of bugs,

And I appreciate that!

> dropped eeprom support since that is secondary for my use case as well as the

I only said the original code had this implemented if someone wants to re-add it
to save them some time not having to re-write it from scratch ;-)

> out-of-tree parity code, and submitted it. I'd be more than happy to let you
> take over if you like.

I’m mostly out of time, so I appreciate you starting the upstream process.

Thank you so much,
	René
Guenter Roeck May 31, 2024, 1:55 p.m. UTC | #26
On 5/31/24 06:20, René Rebe wrote:
> Hi,
> 
>> On May 31, 2024, at 15:14, Guenter Roeck <linux@roeck-us.net> wrote:
>>
>> Hi René,
>>
>> On 5/31/24 03:01, René Rebe wrote:
>>> Hi,
>>> On May 31, 2024, at 11:31, Wolfram Sang <wsa+renesas@sang-engineering.com> wrote:
>>>>
>>>> Hi all,
>>>>
>>>>>> Wolfgang seems to think it's important:
>>>>
>>>> Wolfram, please.
>>>>
>>>>>> https://lore.kernel.org/lkml/tdia472d4pow2osabef24y2ujkkquplfajxmmtk5pnxllsdxsz@wxzynz7llasr/
>>>>>>
>>>>>
>>>>> Ok, but that doesn't explain the reason. Wolfram, Paul, why do you
>>>>> think this is needed ? Note that I am not opposed to adding spd
>>>>> eeprom support, but I'd like to know why I am doing it before
>>>>> I spend time on it.
>>>>
>>>> A working eeprom driver is needed to get 'decode-dimms' from the
>>>> i2c-tools package working. Jean reported that EEPROM access for DDR5 is
>>>> different from DDR4, so it needs a separate driver. And
>>>> i2c_register_spd() then needs to be updated to use the new driver for
>>>> DDR5.
>>> Well my original downstream driver already had eeprom access:
>>> https://svn.exactcode.de/t2/trunk/package/kernel/linux/spd-5118.patch
>>
>> Yes, but you didn't send it upstream, so I took it, fixed a couple of bugs,
> 
> And I appreciate that!
> 
>> dropped eeprom support since that is secondary for my use case as well as the
> 
> I only said the original code had this implemented if someone wants to re-add it
> to save them some time not having to re-write it from scratch ;-)
> 

That is for sure what I had planned to do.

>> out-of-tree parity code, and submitted it. I'd be more than happy to let you
>> take over if you like.
> 
> I’m mostly out of time, so I appreciate you starting the upstream process.
> 

Ok, I'll keep going.

Thanks,
Guenter
diff mbox series

Patch

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 03d313af469a..6e7b8726b60c 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -215,6 +215,7 @@  Hardware Monitoring Kernel Drivers
    smsc47m192
    smsc47m1
    sparx5-temp
+   spd5118
    stpddc60
    surface_fan
    sy7636a-hwmon
diff --git a/Documentation/hwmon/spd5118.rst b/Documentation/hwmon/spd5118.rst
new file mode 100644
index 000000000000..67e990551a8a
--- /dev/null
+++ b/Documentation/hwmon/spd5118.rst
@@ -0,0 +1,60 @@ 
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver spd5118
+=====================
+
+Supported chips:
+
+  * SPD5118 (JEDEC JESD300-5B.01) compliant temperature sensor chips
+
+    JEDEC standard download:
+	https://www.jedec.org/standards-documents/docs/jesd300-5b01
+	(account required)
+
+
+    Prefix: 'spd5118'
+
+    Addresses scanned: I2C 0x50 - 0x57
+
+Author:
+	Guenter Roeck <linux@roeck-us.net>
+
+
+Description
+-----------
+
+This driver implements support for SPD5118 (JEDEC JESD300-5B.01) compliant
+temperature sensors, which are used on many DDR5 memory modules. Some systems
+use the sensor to prevent memory overheating by automatically throttling
+the memory controller.
+
+The driver auto-detects SPD5118 compliant chips, but can also be instantiated
+using devicetree/firmware nodes.
+
+A SPD5118 compliant chip supports a single temperature sensor. Critical minimum,
+minimum, maximum, and critical temperature can be configured. There are alarms
+for low critical, low, high, and critical thresholds.
+
+
+PEC configuration
+-----------------
+
+If the I2C/SMBus controller supports PEC, it can be enabled or disabled using
+the 'pec' sysfs attribute attached to the i2c device.
+
+
+Hardware monitoring sysfs entries
+---------------------------------
+
+======================= ==================================
+temp1_input		Temperature (RO)
+temp1_lcrit		Low critical high temperature (RW)
+temp1_min		Minimum temperature (RW)
+temp1_max		Maximum temperature (RW)
+temp1_crit		Critical high temperature (RW)
+
+temp1_lcrit_alarm	Temperature low critical alarm
+temp1_min_alarm		Temperature low alarm
+temp1_max_alarm		Temperature high alarm
+temp1_crit_alarm	Temperature critical alarm
+======================= ===========================================
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 7f384a2494c9..111d05718b89 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -2182,6 +2182,18 @@  config SENSORS_INA3221
 	  This driver can also be built as a module. If so, the module
 	  will be called ina3221.
 
+config SENSORS_SPD5118
+	tristate "SPD5118 Compliant Temperature Sensors"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  If you say yes here you get support for SPD5118 (JEDEC JESD300-5B)
+	  compliant temperature sensors. Such sensors are found on DDR5 memory
+	  modules.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called spd5118.
+
 config SENSORS_TC74
 	tristate "Microchip TC74"
 	depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index e3f25475d1f0..07c593fae9a3 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -207,6 +207,7 @@  obj-$(CONFIG_SENSORS_SMSC47B397)+= smsc47b397.o
 obj-$(CONFIG_SENSORS_SMSC47M1)	+= smsc47m1.o
 obj-$(CONFIG_SENSORS_SMSC47M192)+= smsc47m192.o
 obj-$(CONFIG_SENSORS_SPARX5)	+= sparx5-temp.o
+obj-$(CONFIG_SENSORS_SPD51118)	+= spd5118.o
 obj-$(CONFIG_SENSORS_STTS751)	+= stts751.o
 obj-$(CONFIG_SENSORS_SURFACE_FAN)+= surface_fan.o
 obj-$(CONFIG_SENSORS_SY7636A)	+= sy7636a-hwmon.o
diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c
new file mode 100644
index 000000000000..440503d09d13
--- /dev/null
+++ b/drivers/hwmon/spd5118.c
@@ -0,0 +1,482 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for Jedec 5118 compliant temperature sensors
+ *
+ * Derived from https://github.com/Steve-Tech/SPD5118-DKMS
+ * Originally from T/2 driver at https://t2sde.org/packages/linux
+ *	Copyright (c) 2023 René Rebe, ExactCODE GmbH; Germany.
+ *
+ * Copyright (c) 2024 Guenter Roeck
+ *
+ * Inspired by ee1004.c and jc42.c.
+ *
+ * SPD5118 compliant temperature sensors are typically used on DDR5
+ * memory modules.
+ */
+
+#include <linux/bitops.h>
+#include <linux/bits.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/units.h>
+
+/* Addresses to scan */
+static const unsigned short normal_i2c[] = {
+	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, I2C_CLIENT_END };
+
+/* SPD5118 registers. */
+#define SPD5118_REG_TYPE		0x00	/* MR0:MR1 */
+#define SPD5118_REG_REVISION		0x02	/* MR2 */
+#define SPD5118_REG_VENDOR		0x03	/* MR3:MR4 */
+#define SPD5118_REG_CAPABILITY		0x05	/* MR5 */
+#define SPD5118_REG_I2C_LEGACY_MODE	0x0B	/* MR11 */
+#define SPD5118_REG_TEMP_CLR		0x13	/* MR19 */
+#define SPD5118_REG_ERROR_CLR		0x14	/* MR20 */
+#define SPD5118_REG_TEMP_CONFIG		0x1A	/* MR26 */
+#define SPD5118_REG_TEMP_MAX		0x1c	/* MR28:MR29 */
+#define SPD5118_REG_TEMP_MIN		0x1e	/* MR30:MR31 */
+#define SPD5118_REG_TEMP_CRIT		0x20	/* MR32:MR33 */
+#define SPD5118_REG_TEMP_LCRIT		0x22	/* MR34:MR35 */
+#define SPD5118_REG_TEMP		0x31	/* MR49:MR50 */
+#define SPD5118_REG_TEMP_STATUS		0x33	/* MR51 */
+
+#define SPD5118_TEMP_STATUS_HIGH	BIT(0)
+#define SPD5118_TEMP_STATUS_LOW		BIT(1)
+#define SPD5118_TEMP_STATUS_CRIT	BIT(2)
+#define SPD5118_TEMP_STATUS_LCRIT	BIT(3)
+
+#define SPD5118_CAP_TS_SUPPORT		BIT(1)	/* temperature sensor support */
+
+#define SPD5118_TS_DISABLE		BIT(0)	/* temperature sensor disable */
+
+/* Temperature unit in millicelsius */
+#define SPD5118_TEMP_UNIT		(MILLIDEGREE_PER_DEGREE / 4)
+/* Representable temperature range in millicelsius */
+#define SPD5118_TEMP_RANGE_MIN		-256000
+#define SPD5118_TEMP_RANGE_MAX		255750
+
+static int spd5118_temp_from_reg(u16 reg)
+{
+	int temp = sign_extend32(reg >> 2, 10);
+
+	return temp * SPD5118_TEMP_UNIT;
+}
+
+static u16 spd5118_temp_to_reg(long temp)
+{
+	temp = clamp_val(temp, SPD5118_TEMP_RANGE_MIN, SPD5118_TEMP_RANGE_MAX);
+	return (DIV_ROUND_CLOSEST(temp, SPD5118_TEMP_UNIT) & 0x7ff) << 2;
+}
+
+static int spd5118_read_temp(struct regmap *regmap, u32 attr, long *val)
+{
+	int reg, err;
+	u8 regval[2];
+	u16 temp;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		reg = SPD5118_REG_TEMP;
+		break;
+	case hwmon_temp_max:
+		reg = SPD5118_REG_TEMP_MAX;
+		break;
+	case hwmon_temp_min:
+		reg = SPD5118_REG_TEMP_MIN;
+		break;
+	case hwmon_temp_crit:
+		reg = SPD5118_REG_TEMP_CRIT;
+		break;
+	case hwmon_temp_lcrit:
+		reg = SPD5118_REG_TEMP_LCRIT;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	err = regmap_bulk_read(regmap, reg, regval, 2);
+	if (err)
+		return err;
+
+	temp = (regval[1] << 8) | regval[0];
+
+	*val = spd5118_temp_from_reg(temp);
+	return 0;
+}
+
+static int spd5118_read_alarm(struct regmap *regmap, u32 attr, long *val)
+{
+	unsigned int mask, regval;
+	int err;
+
+	switch (attr) {
+	case hwmon_temp_max_alarm:
+		mask = SPD5118_TEMP_STATUS_HIGH;
+		break;
+	case hwmon_temp_min_alarm:
+		mask = SPD5118_TEMP_STATUS_LOW;
+		break;
+	case hwmon_temp_crit_alarm:
+		mask = SPD5118_TEMP_STATUS_CRIT;
+		break;
+	case hwmon_temp_lcrit_alarm:
+		mask = SPD5118_TEMP_STATUS_LCRIT;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	err = regmap_read(regmap, SPD5118_REG_TEMP_STATUS, &regval);
+	if (err < 0)
+		return err;
+	*val = !!(regval & mask);
+	if (*val)
+		return regmap_write(regmap, SPD5118_REG_TEMP_CLR, mask);
+	return 0;
+}
+
+static int spd5118_read_enable(struct regmap *regmap, u32 attr, long *val)
+{
+	u32 regval;
+	int err;
+
+	err = regmap_read(regmap, SPD5118_REG_TEMP_CONFIG, &regval);
+	if (err < 0)
+		return err;
+	*val = !(regval & SPD5118_TS_DISABLE);
+	return 0;
+}
+
+static int spd5118_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+	struct regmap *regmap = dev_get_drvdata(dev);
+
+	if (type != hwmon_temp)
+		return -EOPNOTSUPP;
+
+	switch (attr) {
+	case hwmon_temp_input:
+	case hwmon_temp_max:
+	case hwmon_temp_min:
+	case hwmon_temp_crit:
+	case hwmon_temp_lcrit:
+		return spd5118_read_temp(regmap, attr, val);
+	case hwmon_temp_max_alarm:
+	case hwmon_temp_min_alarm:
+	case hwmon_temp_crit_alarm:
+	case hwmon_temp_lcrit_alarm:
+		return spd5118_read_alarm(regmap, attr, val);
+	case hwmon_temp_enable:
+		return spd5118_read_enable(regmap, attr, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int spd5118_write_temp(struct regmap *regmap, u32 attr, long val)
+{
+	u8 regval[2];
+	u16 temp;
+	int reg;
+
+	switch (attr) {
+	case hwmon_temp_max:
+		reg = SPD5118_REG_TEMP_MAX;
+		break;
+	case hwmon_temp_min:
+		reg = SPD5118_REG_TEMP_MIN;
+		break;
+	case hwmon_temp_crit:
+		reg = SPD5118_REG_TEMP_CRIT;
+		break;
+	case hwmon_temp_lcrit:
+		reg = SPD5118_REG_TEMP_LCRIT;
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	temp = spd5118_temp_to_reg(val);
+	regval[0] = temp & 0xff;
+	regval[1] = temp >> 8;
+
+	return regmap_bulk_write(regmap, reg, regval, 2);
+}
+
+static int spd5118_write_enable(struct regmap *regmap, u32 attr, long val)
+{
+	if (val && val != 1)
+		return -EINVAL;
+
+	return regmap_update_bits(regmap, SPD5118_REG_TEMP_CONFIG,
+				  SPD5118_TS_DISABLE,
+				  val ? 0 : SPD5118_TS_DISABLE);
+}
+
+static int spd5118_temp_write(struct regmap *regmap, u32 attr, long val)
+{
+	switch (attr) {
+	case hwmon_temp_max:
+	case hwmon_temp_min:
+	case hwmon_temp_crit:
+	case hwmon_temp_lcrit:
+		return spd5118_write_temp(regmap, attr, val);
+	case hwmon_temp_enable:
+		return spd5118_write_enable(regmap, attr, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int spd5118_write(struct device *dev, enum hwmon_sensor_types type,
+			 u32 attr, int channel, long val)
+{
+	struct regmap *regmap = dev_get_drvdata(dev);
+
+	switch (type) {
+	case hwmon_temp:
+		return spd5118_temp_write(regmap, attr, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static umode_t spd5118_is_visible(const void *_data, enum hwmon_sensor_types type,
+				  u32 attr, int channel)
+{
+	if (type != hwmon_temp)
+		return 0;
+
+	switch (attr) {
+	case hwmon_temp_input:
+		return 0444;
+	case hwmon_temp_min:
+	case hwmon_temp_max:
+	case hwmon_temp_lcrit:
+	case hwmon_temp_crit:
+	case hwmon_temp_enable:
+		return 0644;
+	case hwmon_temp_min_alarm:
+	case hwmon_temp_max_alarm:
+	case hwmon_temp_crit_alarm:
+	case hwmon_temp_lcrit_alarm:
+		return 0444;
+	default:
+		return 0;
+	}
+}
+
+static inline bool spd5118_parity8(u8 w)
+{
+	w ^= w >> 4;
+	return (0x6996 >> (w & 0xf)) & 1;
+}
+
+/*
+ * Bank and vendor id are 8-bit fields with seven data bits and odd parity.
+ * Vendor IDs 0 and 0x7f are invalid.
+ * See Jedec standard JEP106BJ for details and a list of assigned vendor IDs.
+ */
+static bool spd5118_vendor_valid(u8 bank, u8 id)
+{
+	if (!spd5118_parity8(bank) || !spd5118_parity8(id))
+		return false;
+
+	id &= 0x7f;
+	return id && id != 0x7f;
+}
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int spd5118_detect(struct i2c_client *client, struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	int regval;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+				     I2C_FUNC_SMBUS_WORD_DATA))
+		return -ENODEV;
+
+	regval = i2c_smbus_read_word_swapped(client, SPD5118_REG_TYPE);
+	if (regval != 0x5118)
+		return -ENODEV;
+
+	regval = i2c_smbus_read_word_data(client, SPD5118_REG_VENDOR);
+	if (regval < 0 || !spd5118_vendor_valid(regval & 0xff, regval >> 8))
+		return -ENODEV;
+
+	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_CAPABILITY);
+	if (regval < 0)
+		return -ENODEV;
+
+	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_TEMP_CLR);
+	if (regval)
+		return -ENODEV;
+	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_ERROR_CLR);
+	if (regval)
+		return -ENODEV;
+
+	if (!(regval & SPD5118_CAP_TS_SUPPORT) || (regval & 0xfc))
+		return -ENODEV;
+
+	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_REVISION);
+	if (regval < 0 || (regval & 0xc1))
+		return -ENODEV;
+
+	regval = i2c_smbus_read_byte_data(client, SPD5118_REG_TEMP_CONFIG);
+	if (regval < 0)
+		return -ENODEV;
+	if (regval & ~SPD5118_TS_DISABLE)
+		return -ENODEV;
+
+	strscpy(info->type, "spd5118", I2C_NAME_SIZE);
+	return 0;
+}
+
+static const struct hwmon_channel_info *spd5118_info[] = {
+	HWMON_CHANNEL_INFO(chip,
+			   HWMON_C_REGISTER_TZ),
+	HWMON_CHANNEL_INFO(temp,
+			   HWMON_T_INPUT |
+			   HWMON_T_LCRIT | HWMON_T_LCRIT_ALARM |
+			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
+			   HWMON_T_MAX | HWMON_T_MAX_ALARM |
+			   HWMON_T_CRIT | HWMON_T_CRIT_ALARM |
+			   HWMON_T_ENABLE),
+	NULL
+};
+
+static const struct hwmon_ops spd5118_hwmon_ops = {
+	.is_visible = spd5118_is_visible,
+	.read = spd5118_read,
+	.write = spd5118_write,
+};
+
+static const struct hwmon_chip_info spd5118_chip_info = {
+	.ops = &spd5118_hwmon_ops,
+	.info = spd5118_info,
+};
+
+static bool spd5118_writeable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case SPD5118_REG_TEMP_CLR:
+	case SPD5118_REG_TEMP_CONFIG:
+	case SPD5118_REG_TEMP_MAX:
+	case SPD5118_REG_TEMP_MAX + 1:
+	case SPD5118_REG_TEMP_MIN:
+	case SPD5118_REG_TEMP_MIN + 1:
+	case SPD5118_REG_TEMP_CRIT:
+	case SPD5118_REG_TEMP_CRIT + 1:
+	case SPD5118_REG_TEMP_LCRIT:
+	case SPD5118_REG_TEMP_LCRIT + 1:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool spd5118_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case SPD5118_REG_TEMP_CLR:
+	case SPD5118_REG_ERROR_CLR:
+	case SPD5118_REG_TEMP:
+	case SPD5118_REG_TEMP + 1:
+	case SPD5118_REG_TEMP_STATUS:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static const struct regmap_config spd5118_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = SPD5118_REG_TEMP_STATUS,
+	.writeable_reg = spd5118_writeable_reg,
+	.volatile_reg = spd5118_volatile_reg,
+	.cache_type = REGCACHE_MAPLE,
+};
+
+static int spd5118_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	unsigned int regval, revision, vendor, bank;
+	struct device *hwmon_dev;
+	struct regmap *regmap;
+	int err;
+
+	regmap = devm_regmap_init_i2c(client, &spd5118_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap), "regmap init failed\n");
+
+	err = regmap_read(regmap, SPD5118_REG_CAPABILITY, &regval);
+	if (err)
+		return err;
+	if (!(regval & SPD5118_CAP_TS_SUPPORT))
+		return -ENODEV;
+
+	err = regmap_read(regmap, SPD5118_REG_REVISION, &revision);
+	if (err)
+		return err;
+
+	err = regmap_read(regmap, SPD5118_REG_VENDOR, &bank);
+	if (err)
+		return err;
+	err = regmap_read(regmap, SPD5118_REG_VENDOR + 1, &vendor);
+	if (err)
+		return err;
+	if (!spd5118_vendor_valid(bank, vendor))
+		return -ENODEV;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, "spd5118",
+							 regmap, &spd5118_chip_info,
+							 NULL);
+	if (IS_ERR(hwmon_dev))
+		return PTR_ERR(hwmon_dev);
+
+	/*
+	 * From JESD300-5B
+	 *   MR2 bits [5:4]: Major revision, 1..4
+	 *   MR2 bits [3:1]: Minor revision, 0..8? Probably a typo, assume 1..8
+	 */
+	dev_info(dev, "DDR5 temperature sensor: vendor 0x%02x:0x%02x revision %d.%d\n",
+		 bank & 0x7f, vendor, ((revision >> 4) & 0x03) + 1, ((revision >> 1) & 0x07) + 1);
+
+	return 0;
+}
+
+static const struct i2c_device_id spd5118_id[] = {
+	{ "spd5118", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, spd5118_id);
+
+static const struct of_device_id spd5118_of_ids[] = {
+	{ .compatible = "jedec,spd5118", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, spd5118_of_ids);
+
+static struct i2c_driver spd5118_driver = {
+	.class		= I2C_CLASS_HWMON,
+	.driver = {
+		.name	= "spd5118",
+		.of_match_table = spd5118_of_ids,
+	},
+	.probe		= spd5118_probe,
+	.id_table	= spd5118_id,
+	.detect		= spd5118_detect,
+	.address_list	= normal_i2c,
+};
+
+module_i2c_driver(spd5118_driver);
+
+MODULE_AUTHOR("René Rebe <rene@exactcode.de>");
+MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
+MODULE_DESCRIPTION("SPD 5118 driver");
+MODULE_LICENSE("GPL");