diff mbox series

[1/2] hwmon: (pmbus/max20754) Add support for MAX20754

Message ID 3659043f92b0ca9e538679e00f7dcc214525ff2e.1657204859.git.atif.ofluoglu@analog.com (mailing list archive)
State Changes Requested
Headers show
Series Adding MAX20754 support | expand

Commit Message

Atif Ofluoglu July 7, 2022, 3:29 p.m. UTC 
From: Atif Ofluoglu <atif.ofluoglu@analog.com>

Signed-off-by: Atif Ofluoglu <Atif.Ofluoglu@analog.com>
---
 drivers/hwmon/pmbus/Kconfig    |   9 +
 drivers/hwmon/pmbus/Makefile   |   1 +
 drivers/hwmon/pmbus/max20754.c | 390 +++++++++++++++++++++++++++++++++
 3 files changed, 400 insertions(+)
 create mode 100644 drivers/hwmon/pmbus/max20754.c

Comments

kernel test robot July 7, 2022, 6:56 p.m. UTC | #1 
Hi Atif,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on groeck-staging/hwmon-next]
[also build test ERROR on linus/master v5.19-rc5 next-20220707]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Atif-Ofluoglu/Adding-MAX20754-support/20220707-233249
base:   https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
config: arc-randconfig-r043-20220707 (https://download.01.org/0day-ci/archive/20220708/202207080255.fBmFH9Ry-lkp@intel.com/config)
compiler: arceb-elf-gcc (GCC) 11.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/52ef0855bc74f95cd6c170b5475a3e957d7e1028
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Atif-Ofluoglu/Adding-MAX20754-support/20220707-233249
        git checkout 52ef0855bc74f95cd6c170b5475a3e957d7e1028
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=arc SHELL=/bin/bash drivers/hwmon/pmbus/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/hwmon/pmbus/max20754.c:381:19: error: 'pmbus_do_remove' undeclared here (not in a function); did you mean 'pmbus_do_probe'?
     381 |         .remove = pmbus_do_remove,
         |                   ^~~~~~~~~~~~~~~
         |                   pmbus_do_probe


vim +381 drivers/hwmon/pmbus/max20754.c

   375	
   376	static struct i2c_driver max20754_driver = {
   377		.driver = {
   378			   .name = "max20754",
   379			   },
   380		.probe_new = max20754_probe,
 > 381		.remove = pmbus_do_remove,
   382		.id_table = max20754_id,
   383	};
   384
Guenter Roeck July 13, 2022, 2:16 p.m. UTC | #2 
On Thu, Jul 07, 2022 at 03:29:17PM +0000, Atif Ofluoglu wrote:
> From: Atif Ofluoglu <atif.ofluoglu@analog.com>
> 
> Signed-off-by: Atif Ofluoglu <Atif.Ofluoglu@analog.com>

Please use lowercase for the e-mail address to avoid confusing
checkpatch.

> ---
>  drivers/hwmon/pmbus/Kconfig    |   9 +
>  drivers/hwmon/pmbus/Makefile   |   1 +
>  drivers/hwmon/pmbus/max20754.c | 390 +++++++++++++++++++++++++++++++++
>  3 files changed, 400 insertions(+)
>  create mode 100644 drivers/hwmon/pmbus/max20754.c
> 
> diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
> index dfae76db65ae..f259b8739766 100644
> --- a/drivers/hwmon/pmbus/Kconfig
> +++ b/drivers/hwmon/pmbus/Kconfig
> @@ -254,6 +254,15 @@ config SENSORS_MAX20751
>  	  This driver can also be built as a module. If so, the module will
>  	  be called max20751.
>  
> +config SENSORS_MAX20754
> +	tristate "Maxim MAX20754"
> +	help
> +	  If you say yes here you get hardware monitoring support for Maxim
> +	  MAX20754.
> +
> +	  This driver can also be built as a module. If so, the module will
> +	  be called max20754.
> +
>  config SENSORS_MAX31785
>  	tristate "Maxim MAX31785 and compatibles"
>  	help
> diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
> index 4678fba5012c..b8b1d8a84b3b 100644
> --- a/drivers/hwmon/pmbus/Makefile
> +++ b/drivers/hwmon/pmbus/Makefile
> @@ -27,6 +27,7 @@ obj-$(CONFIG_SENSORS_MAX16064)	+= max16064.o
>  obj-$(CONFIG_SENSORS_MAX16601)	+= max16601.o
>  obj-$(CONFIG_SENSORS_MAX20730)	+= max20730.o
>  obj-$(CONFIG_SENSORS_MAX20751)	+= max20751.o
> +obj-$(CONFIG_SENSORS_MAX20751)	+= max20754.o
>  obj-$(CONFIG_SENSORS_MAX31785)	+= max31785.o
>  obj-$(CONFIG_SENSORS_MAX34440)	+= max34440.o
>  obj-$(CONFIG_SENSORS_MAX8688)	+= max8688.o
> diff --git a/drivers/hwmon/pmbus/max20754.c b/drivers/hwmon/pmbus/max20754.c
> new file mode 100644
> index 000000000000..5e29e8f8009b
> --- /dev/null
> +++ b/drivers/hwmon/pmbus/max20754.c
> @@ -0,0 +1,390 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Maxim MAX20754 Dual-Output, Configurable Multiphase
> + * Power-Supply Controller with PMBus Interface
> + * and Internal Buck Converter Driver
> + *
> + * Author: Atif Emre Ofluoglu <atif.ofluoglu@analog.com>
> + * Copyright (C) 2022 Analog Devices
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under  the terms of  the GNU General  Public License as published
> + * by the Free Software Foundation;  either version 2 of the  License,
> + * or (at your option) any later version.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/hwmon.h>

Alphabetic include file order, please.

> +#include <linux/hwmon-sysfs.h>

Not needed.

> +#include "pmbus.h"
> +
> +enum chips { max20754 };

Not needed unless you plan to add another chip to the driver later on,
and then it should be added with the patch introducing that chip.

> +
> +#define MAX20754_NUM_PHASES 6
> +#define MAX20754_LINEAR_EXPONENT -10

#define<space>NAME<tab>value, please. Also, (-10)

> +
> +struct max20754_data {
> +	enum chips id;
> +	struct pmbus_driver_info info;
> +	struct i2c_client *rail2;
> +	bool smbus_i2c_block_read;
> +};
> +
> +#define to_max20754_data(x) container_of(x, struct max20754_data, info)
> +
> +enum max20754_reg_index {
> +	operation_index,
> +	on_off_config_index,
> +	vout_command_index,
> +	num_regs,
> +};
> +
> +static const u8 max20754_regs[num_regs][2] = {
> +	[operation_index] = {PMBUS_OPERATION, 1},
> +	[on_off_config_index] = {PMBUS_ON_OFF_CONFIG, 1},
> +	[vout_command_index] = {PMBUS_VOUT_COMMAND, 2},
> +};
> +
> +static u16 val_to_linear16(int val)
> +{
> +	return ((u16)val * 1000LL) >> -MAX20754_LINEAR_EXPONENT;

Double negation whenever MAX20754_LINEAR_EXPONENT ? What is the point
of that ?

> +}
> +
> +static long linear16_to_val(s64 val)
> +{
> +	if (val == 0)
> +		return 0;

Why is that needed ?

> +
> +	val <<= -MAX20754_LINEAR_EXPONENT;
> +	val = DIV_ROUND_CLOSEST_ULL(val, 1000);
> +	val = clamp_val(val, 0, 0xffff);
> +	return val;
> +}
> +
> +static int max20754_read_block_data(struct i2c_client *client, int reg,
> +				    u8 length, u8 *values)
> +{
> +	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> +	struct max20754_data *data = to_max20754_data(info);
> +	int ret;
> +
> +	if (data->smbus_i2c_block_read) {
> +		ret = i2c_smbus_read_i2c_block_data(client, reg, length, values);
> +		if (ret < 1)
> +			return ret;
> +		ret = ret - 1;
> +		memcpy(values, &values[1], ret);
> +	} else {
> +		ret = i2c_smbus_read_block_data(client, reg, values);
> +	}
> +
> +	return ret;
> +}
> +
> +static int max20754_read_word(struct i2c_client *client, int page, int phase,
> +			      int reg)
> +{
> +	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> +	struct max20754_data *data = to_max20754_data(info);
> +
> +	if (reg > 0xFF)
> +		return -ENXIO;
> +
> +	if (reg == PMBUS_MFR_VOUT_MAX)
> +		reg = PMBUS_VOUT_MAX;
> +

I don't think this makes sense. MFR_VOUT_MAX is the _rated_
maximum output voltage, while VOUT_MAX is the _configured_ maximum
output voltage. Those are distinctly diffferent.

> +	switch (page) {
> +	case 0:		/* RAIL1 */
> +		return i2c_smbus_read_word_data(client, reg);
> +	case 1:		/* RAIL2 */
> +		return i2c_smbus_read_word_data(data->rail2, reg);
> +	default:
> +		return -ENODATA;
> +	}
> +
> +	return -ENODATA;
> +}
> +
> +static int max20754_write_word(struct i2c_client *client, int page, int reg, u16 value)
> +{
> +	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> +	struct max20754_data *data = to_max20754_data(info);
> +
> +	switch (reg) {
> +	case PMBUS_OPERATION:
> +		if (value >= 0x90 && value <= 0x93)
> +			return -EOPNOTSUPP;
> +		break;
> +	case PMBUS_MFR_VOUT_MAX:
> +		reg = PMBUS_VOUT_MAX;
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	switch (page) {
> +	case 0:		/* RAIL1 */
> +		return i2c_smbus_write_word_data(client, reg, value);
> +	case 1:		/* RAIL2 */
> +		return i2c_smbus_write_word_data(data->rail2, reg, value);
> +	default:
> +		return -EOPNOTSUPP;
> +	}
> +	return -ENODATA;
> +}
> +
> +static int max20754_read_byte(struct i2c_client *client, int page, int reg)
> +{
> +	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> +	struct max20754_data *data = to_max20754_data(info);
> +	int vout_mode;
> +
> +	if (reg == PMBUS_VOUT_MODE) {
> +		vout_mode = i2c_smbus_read_byte_data(client, reg);
> +		if (vout_mode != 0x2C)
> +			vout_mode = 0x16;

This ignores errors.

> +		return vout_mode;

Needs explanation.

> +	}
> +
> +	switch (page) {
> +	case 0:		/* RAIL1 */
> +		return i2c_smbus_read_byte_data(client, reg);
> +	case 1:		/* RAIL2 */
> +		return i2c_smbus_read_byte_data(data->rail2, reg);
> +	default:
> +		return -ENODATA;
> +	}
> +	return -ENODATA;
> +}
> +
> +static int max20754_write_byte(struct i2c_client *client, int page, u8 reg)
> +{
> +	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> +	struct max20754_data *data = to_max20754_data(info);
> +
> +	if (reg == PMBUS_CLEAR_FAULTS) {
> +		switch (page) {
> +		case 0:
> +			return i2c_smbus_write_byte(client, reg);
> +		case 1:
> +			return i2c_smbus_write_byte(data->rail2, reg);
> +		default:
> +			return -ENODATA;
> +		}
> +	}
> +	return -ENODATA;
> +}
> +
> +static int max20754_identify(struct i2c_client *client,
> +			     struct pmbus_driver_info *info)
> +{
> +	struct device *dev = &client->dev;
> +	u8 buf[9] = {0};
> +	int ret;
> +
> +	ret = max20754_read_block_data(client,
> +				       PMBUS_IC_DEVICE_ID, 9,
> +				       buf);
> +
> +	if (ret < 0 || ret < 8)
> +		return -ENODEV;
> +
> +	/*
> +	 * PMBUS_IC_DEVICE_ID is expected to return "MAX20754"
> +	 */
> +
> +	if (strncmp(buf, "MAX20754", 8)) {
> +		buf[ret] = '\0';
> +		dev_err(dev, "Unsupported chip '%s'\n", buf);
> +		return -ENODEV;
> +	}
> +
> +	return 0;
> +}

The above can and should be handled in the probe function.
With this, the smbus_i2c_block_read boolean in struct max20754_data
is no longer necessary. 

> +
> +static ssize_t max20754_register_store(struct device *dev,
> +				       struct device_attribute *attr, const char *buf,
> +				       size_t count)
> +{
> +	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
> +	struct i2c_client *client = to_i2c_client(dev->parent);
> +	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> +	struct max20754_data *data = to_max20754_data(info);
> +
> +	u8 cmd = max20754_regs[sattr->index][0];
> +	u8 reg_size = max20754_regs[sattr->index][1];
> +	u8 rail_number = sattr->nr;
> +	long val = 0;

Unnecessary initialization.

> +	int ret;
> +
> +	ret = kstrtol(buf, 10, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (rail_number == 1)
> +		client = data->rail2;
> +
> +	if (cmd == PMBUS_VOUT_COMMAND)
> +		val = linear16_to_val(val);
> +
> +	switch (reg_size) {
> +	case 1:
> +		ret = i2c_smbus_write_byte_data(client, cmd, val);
> +		break;
> +	case 2:
> +		ret = i2c_smbus_write_word_data(client, cmd, val);
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	if (ret < 0)
> +		return ret;
> +
> +	return count;
> +}
> +
> +static ssize_t max20754_register_show(struct device *dev,
> +				      struct device_attribute *attr, char *buf)
> +{
> +	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
> +	struct i2c_client *client = to_i2c_client(dev->parent);
> +
> +	int ret_val = 0;

Why ret_val instead of ret like everywhere else ?

> +	u8 cmd = max20754_regs[sattr->index][0];
> +	u8 reg_size = max20754_regs[sattr->index][1];
> +	u8 rail_number = sattr->nr;
> +
> +	switch (reg_size) {
> +	case 1:
> +		ret_val = max20754_read_byte(client, rail_number, cmd);
> +		break;
> +	case 2:
> +		ret_val = max20754_read_word(client, rail_number, 0, cmd);
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	if (ret_val < 0)
> +		return -ENODATA;
> +
> +	if (cmd == PMBUS_VOUT_COMMAND)
> +		ret_val = val_to_linear16(ret_val);
> +
> +	return sprintf(buf, "%d\n", ret_val);
> +}
> +
> +#define MAX20754_REGISTER_ATTR_RW(__name, __reg_index, __size) \
> +	SENSOR_DEVICE_ATTR_2_RW(__name, max20754_register, __size, __reg_index)
> +
> +static MAX20754_REGISTER_ATTR_RW(operation, operation_index, 0);
> +static MAX20754_REGISTER_ATTR_RW(on_off_config, on_off_config_index, 0);
> +
> +static MAX20754_REGISTER_ATTR_RW(vout1_command, vout_command_index, 0);
> +static MAX20754_REGISTER_ATTR_RW(vout2_command, vout_command_index, 1);
> +

The above attributes are not acceptable. Register as regulator(s) if you
want to control output voltage and operation.

> +static struct attribute *max20754_attrs[] = {
> +	&sensor_dev_attr_operation.dev_attr.attr,
> +	&sensor_dev_attr_on_off_config.dev_attr.attr,
> +	&sensor_dev_attr_vout1_command.dev_attr.attr,
> +	&sensor_dev_attr_vout2_command.dev_attr.attr,
> +	NULL
> +};
> +ATTRIBUTE_GROUPS(max20754);
> +
> +static struct pmbus_driver_info max20754_info = {
> +	.pages = 2,
> +	.format[PSC_VOLTAGE_IN] = linear,
> +	.format[PSC_VOLTAGE_OUT] = linear,
> +	.vrm_version[0] = vr12,
> +	.format[PSC_TEMPERATURE] = linear,
> +	.format[PSC_CURRENT_OUT] = linear,
> +	.format[PSC_POWER] = linear,
> +	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
> +		PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
> +		PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP,
> +	.func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_INPUT |
> +		PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
> +		PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP,
> +	.identify = max20754_identify,
> +	.read_byte_data = max20754_read_byte,
> +	.read_word_data = max20754_read_word,
> +	.write_byte = max20754_write_byte,
> +	.write_word_data = max20754_write_word,
> +};
> +
> +static void max20754_remove(void *_data)
> +{
> +	struct max20754_data *data = _data;
> +
> +	i2c_unregister_device(data->rail2);
> +}
> +
> +static int max20754_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct max20754_data *data;
> +	bool i2c_block_data_ok = false;
> +	int ret = 0;

Unnecessary assignment.

> +
> +	ret = i2c_check_functionality(client->adapter,
> +				      I2C_FUNC_SMBUS_READ_BYTE_DATA |
> +				      I2C_FUNC_SMBUS_READ_BLOCK_DATA);
> +
Unnecessary empty line. Also, assigning the return value to a variable
isn't really necessary.

	if (!i2c_check_functionality(...)) {
		...


> +	if (!ret) 
> +		ret = i2c_check_functionality(client->adapter,
> +					      I2C_FUNC_SMBUS_READ_BYTE_DATA |
> +					      I2C_FUNC_SMBUS_I2C_BLOCK);
> +		if (!ret)
> +			return -ENODEV;

		if (!i2c_check_functionality(...))
			return -ENODEV;
> +
> +		i2c_block_data_ok = true;
> +	}
> +
> +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->rail2 = i2c_new_dummy_device(client->adapter, client->addr + 1);
> +	if (IS_ERR(data->rail2)) {
> +		dev_err(dev, "Failed to register rail2 client\n");
> +		return PTR_ERR(data->rail2);
> +	}
> +	ret = devm_add_action_or_reset(dev, max20754_remove, data);
> +	if (ret)
> +		return ret;
> +
> +	data->info = max20754_info;
> +	data->info.groups = max20754_groups;
> +	data->smbus_i2c_block_read = i2c_block_data_ok;
> +
> +	return pmbus_do_probe(client, &data->info);
> +}
> +
> +static const struct i2c_device_id max20754_id[] = {
> +	{"max20754", max20754},
> +	{}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, max20754_id);
> +
> +static struct i2c_driver max20754_driver = {
> +	.driver = {
> +		   .name = "max20754",
> +		   },
> +	.probe_new = max20754_probe,
> +	.remove = pmbus_do_remove,

Please rebase to latest kernel. pmbus_do_remove() no longer exists.

> +	.id_table = max20754_id,
> +};
> +
> +module_i2c_driver(max20754_driver);
> +
> +MODULE_AUTHOR("Atif Emre Ofluoglu <atif.ofluoglu@analog.com>");
> +MODULE_DESCRIPTION("PMBus driver for Maxim MAX20754");
> +MODULE_LICENSE("GPL");
> +MODULE_IMPORT_NS(PMBUS);
diff mbox series

Patch

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index dfae76db65ae..f259b8739766 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -254,6 +254,15 @@  config SENSORS_MAX20751
 	  This driver can also be built as a module. If so, the module will
 	  be called max20751.
 
+config SENSORS_MAX20754
+	tristate "Maxim MAX20754"
+	help
+	  If you say yes here you get hardware monitoring support for Maxim
+	  MAX20754.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called max20754.
+
 config SENSORS_MAX31785
 	tristate "Maxim MAX31785 and compatibles"
 	help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 4678fba5012c..b8b1d8a84b3b 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -27,6 +27,7 @@  obj-$(CONFIG_SENSORS_MAX16064)	+= max16064.o
 obj-$(CONFIG_SENSORS_MAX16601)	+= max16601.o
 obj-$(CONFIG_SENSORS_MAX20730)	+= max20730.o
 obj-$(CONFIG_SENSORS_MAX20751)	+= max20751.o
+obj-$(CONFIG_SENSORS_MAX20751)	+= max20754.o
 obj-$(CONFIG_SENSORS_MAX31785)	+= max31785.o
 obj-$(CONFIG_SENSORS_MAX34440)	+= max34440.o
 obj-$(CONFIG_SENSORS_MAX8688)	+= max8688.o
diff --git a/drivers/hwmon/pmbus/max20754.c b/drivers/hwmon/pmbus/max20754.c
new file mode 100644
index 000000000000..5e29e8f8009b
--- /dev/null
+++ b/drivers/hwmon/pmbus/max20754.c
@@ -0,0 +1,390 @@ 
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Maxim MAX20754 Dual-Output, Configurable Multiphase
+ * Power-Supply Controller with PMBus Interface
+ * and Internal Buck Converter Driver
+ *
+ * Author: Atif Emre Ofluoglu <atif.ofluoglu@analog.com>
+ * Copyright (C) 2022 Analog Devices
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under  the terms of  the GNU General  Public License as published
+ * by the Free Software Foundation;  either version 2 of the  License,
+ * or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include "pmbus.h"
+
+enum chips { max20754 };
+
+#define MAX20754_NUM_PHASES 6
+#define MAX20754_LINEAR_EXPONENT -10
+
+struct max20754_data {
+	enum chips id;
+	struct pmbus_driver_info info;
+	struct i2c_client *rail2;
+	bool smbus_i2c_block_read;
+};
+
+#define to_max20754_data(x) container_of(x, struct max20754_data, info)
+
+enum max20754_reg_index {
+	operation_index,
+	on_off_config_index,
+	vout_command_index,
+	num_regs,
+};
+
+static const u8 max20754_regs[num_regs][2] = {
+	[operation_index] = {PMBUS_OPERATION, 1},
+	[on_off_config_index] = {PMBUS_ON_OFF_CONFIG, 1},
+	[vout_command_index] = {PMBUS_VOUT_COMMAND, 2},
+};
+
+static u16 val_to_linear16(int val)
+{
+	return ((u16)val * 1000LL) >> -MAX20754_LINEAR_EXPONENT;
+}
+
+static long linear16_to_val(s64 val)
+{
+	if (val == 0)
+		return 0;
+
+	val <<= -MAX20754_LINEAR_EXPONENT;
+	val = DIV_ROUND_CLOSEST_ULL(val, 1000);
+	val = clamp_val(val, 0, 0xffff);
+	return val;
+}
+
+static int max20754_read_block_data(struct i2c_client *client, int reg,
+				    u8 length, u8 *values)
+{
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	struct max20754_data *data = to_max20754_data(info);
+	int ret;
+
+	if (data->smbus_i2c_block_read) {
+		ret = i2c_smbus_read_i2c_block_data(client, reg, length, values);
+		if (ret < 1)
+			return ret;
+		ret = ret - 1;
+		memcpy(values, &values[1], ret);
+	} else {
+		ret = i2c_smbus_read_block_data(client, reg, values);
+	}
+
+	return ret;
+}
+
+static int max20754_read_word(struct i2c_client *client, int page, int phase,
+			      int reg)
+{
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	struct max20754_data *data = to_max20754_data(info);
+
+	if (reg > 0xFF)
+		return -ENXIO;
+
+	if (reg == PMBUS_MFR_VOUT_MAX)
+		reg = PMBUS_VOUT_MAX;
+
+	switch (page) {
+	case 0:		/* RAIL1 */
+		return i2c_smbus_read_word_data(client, reg);
+	case 1:		/* RAIL2 */
+		return i2c_smbus_read_word_data(data->rail2, reg);
+	default:
+		return -ENODATA;
+	}
+
+	return -ENODATA;
+}
+
+static int max20754_write_word(struct i2c_client *client, int page, int reg, u16 value)
+{
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	struct max20754_data *data = to_max20754_data(info);
+
+	switch (reg) {
+	case PMBUS_OPERATION:
+		if (value >= 0x90 && value <= 0x93)
+			return -EOPNOTSUPP;
+		break;
+	case PMBUS_MFR_VOUT_MAX:
+		reg = PMBUS_VOUT_MAX;
+		break;
+	default:
+		break;
+	}
+
+	switch (page) {
+	case 0:		/* RAIL1 */
+		return i2c_smbus_write_word_data(client, reg, value);
+	case 1:		/* RAIL2 */
+		return i2c_smbus_write_word_data(data->rail2, reg, value);
+	default:
+		return -EOPNOTSUPP;
+	}
+	return -ENODATA;
+}
+
+static int max20754_read_byte(struct i2c_client *client, int page, int reg)
+{
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	struct max20754_data *data = to_max20754_data(info);
+	int vout_mode;
+
+	if (reg == PMBUS_VOUT_MODE) {
+		vout_mode = i2c_smbus_read_byte_data(client, reg);
+		if (vout_mode != 0x2C)
+			vout_mode = 0x16;
+		return vout_mode;
+	}
+
+	switch (page) {
+	case 0:		/* RAIL1 */
+		return i2c_smbus_read_byte_data(client, reg);
+	case 1:		/* RAIL2 */
+		return i2c_smbus_read_byte_data(data->rail2, reg);
+	default:
+		return -ENODATA;
+	}
+	return -ENODATA;
+}
+
+static int max20754_write_byte(struct i2c_client *client, int page, u8 reg)
+{
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	struct max20754_data *data = to_max20754_data(info);
+
+	if (reg == PMBUS_CLEAR_FAULTS) {
+		switch (page) {
+		case 0:
+			return i2c_smbus_write_byte(client, reg);
+		case 1:
+			return i2c_smbus_write_byte(data->rail2, reg);
+		default:
+			return -ENODATA;
+		}
+	}
+	return -ENODATA;
+}
+
+static int max20754_identify(struct i2c_client *client,
+			     struct pmbus_driver_info *info)
+{
+	struct device *dev = &client->dev;
+	u8 buf[9] = {0};
+	int ret;
+
+	ret = max20754_read_block_data(client,
+				       PMBUS_IC_DEVICE_ID, 9,
+				       buf);
+
+	if (ret < 0 || ret < 8)
+		return -ENODEV;
+
+	/*
+	 * PMBUS_IC_DEVICE_ID is expected to return "MAX20754"
+	 */
+
+	if (strncmp(buf, "MAX20754", 8)) {
+		buf[ret] = '\0';
+		dev_err(dev, "Unsupported chip '%s'\n", buf);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static ssize_t max20754_register_store(struct device *dev,
+				       struct device_attribute *attr, const char *buf,
+				       size_t count)
+{
+	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	struct max20754_data *data = to_max20754_data(info);
+
+	u8 cmd = max20754_regs[sattr->index][0];
+	u8 reg_size = max20754_regs[sattr->index][1];
+	u8 rail_number = sattr->nr;
+	long val = 0;
+	int ret;
+
+	ret = kstrtol(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	if (rail_number == 1)
+		client = data->rail2;
+
+	if (cmd == PMBUS_VOUT_COMMAND)
+		val = linear16_to_val(val);
+
+	switch (reg_size) {
+	case 1:
+		ret = i2c_smbus_write_byte_data(client, cmd, val);
+		break;
+	case 2:
+		ret = i2c_smbus_write_word_data(client, cmd, val);
+		break;
+	default:
+		break;
+	}
+
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+
+static ssize_t max20754_register_show(struct device *dev,
+				      struct device_attribute *attr, char *buf)
+{
+	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
+	struct i2c_client *client = to_i2c_client(dev->parent);
+
+	int ret_val = 0;
+	u8 cmd = max20754_regs[sattr->index][0];
+	u8 reg_size = max20754_regs[sattr->index][1];
+	u8 rail_number = sattr->nr;
+
+	switch (reg_size) {
+	case 1:
+		ret_val = max20754_read_byte(client, rail_number, cmd);
+		break;
+	case 2:
+		ret_val = max20754_read_word(client, rail_number, 0, cmd);
+		break;
+	default:
+		break;
+	}
+
+	if (ret_val < 0)
+		return -ENODATA;
+
+	if (cmd == PMBUS_VOUT_COMMAND)
+		ret_val = val_to_linear16(ret_val);
+
+	return sprintf(buf, "%d\n", ret_val);
+}
+
+#define MAX20754_REGISTER_ATTR_RW(__name, __reg_index, __size) \
+	SENSOR_DEVICE_ATTR_2_RW(__name, max20754_register, __size, __reg_index)
+
+static MAX20754_REGISTER_ATTR_RW(operation, operation_index, 0);
+static MAX20754_REGISTER_ATTR_RW(on_off_config, on_off_config_index, 0);
+
+static MAX20754_REGISTER_ATTR_RW(vout1_command, vout_command_index, 0);
+static MAX20754_REGISTER_ATTR_RW(vout2_command, vout_command_index, 1);
+
+static struct attribute *max20754_attrs[] = {
+	&sensor_dev_attr_operation.dev_attr.attr,
+	&sensor_dev_attr_on_off_config.dev_attr.attr,
+	&sensor_dev_attr_vout1_command.dev_attr.attr,
+	&sensor_dev_attr_vout2_command.dev_attr.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(max20754);
+
+static struct pmbus_driver_info max20754_info = {
+	.pages = 2,
+	.format[PSC_VOLTAGE_IN] = linear,
+	.format[PSC_VOLTAGE_OUT] = linear,
+	.vrm_version[0] = vr12,
+	.format[PSC_TEMPERATURE] = linear,
+	.format[PSC_CURRENT_OUT] = linear,
+	.format[PSC_POWER] = linear,
+	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
+		PMBUS_HAVE_STATUS_INPUT | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+		PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP,
+	.func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT | PMBUS_HAVE_STATUS_INPUT |
+		PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT |
+		PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP,
+	.identify = max20754_identify,
+	.read_byte_data = max20754_read_byte,
+	.read_word_data = max20754_read_word,
+	.write_byte = max20754_write_byte,
+	.write_word_data = max20754_write_word,
+};
+
+static void max20754_remove(void *_data)
+{
+	struct max20754_data *data = _data;
+
+	i2c_unregister_device(data->rail2);
+}
+
+static int max20754_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct max20754_data *data;
+	bool i2c_block_data_ok = false;
+	int ret = 0;
+
+	ret = i2c_check_functionality(client->adapter,
+				      I2C_FUNC_SMBUS_READ_BYTE_DATA |
+				      I2C_FUNC_SMBUS_READ_BLOCK_DATA);
+
+	if (!ret) {
+		ret = i2c_check_functionality(client->adapter,
+					      I2C_FUNC_SMBUS_READ_BYTE_DATA |
+					      I2C_FUNC_SMBUS_I2C_BLOCK);
+		if (!ret)
+			return -ENODEV;
+
+		i2c_block_data_ok = true;
+	}
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->rail2 = i2c_new_dummy_device(client->adapter, client->addr + 1);
+	if (IS_ERR(data->rail2)) {
+		dev_err(dev, "Failed to register rail2 client\n");
+		return PTR_ERR(data->rail2);
+	}
+	ret = devm_add_action_or_reset(dev, max20754_remove, data);
+	if (ret)
+		return ret;
+
+	data->info = max20754_info;
+	data->info.groups = max20754_groups;
+	data->smbus_i2c_block_read = i2c_block_data_ok;
+
+	return pmbus_do_probe(client, &data->info);
+}
+
+static const struct i2c_device_id max20754_id[] = {
+	{"max20754", max20754},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, max20754_id);
+
+static struct i2c_driver max20754_driver = {
+	.driver = {
+		   .name = "max20754",
+		   },
+	.probe_new = max20754_probe,
+	.remove = pmbus_do_remove,
+	.id_table = max20754_id,
+};
+
+module_i2c_driver(max20754_driver);
+
+MODULE_AUTHOR("Atif Emre Ofluoglu <atif.ofluoglu@analog.com>");
+MODULE_DESCRIPTION("PMBus driver for Maxim MAX20754");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PMBUS);