[RFT,v3,4/4] hwmon: (spd5118) Add support for reading SPD data

Message ID	20240531230556.1409532-5-linux@roeck-us.net (mailing list archive)
State	Superseded
Headers	show Received: from mail-pg1-f182.google.com (mail-pg1-f182.google.com [209.85.215.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0A9A31311A8; Fri, 31 May 2024 23:06:08 +0000 (UTC) Sender: Guenter Roeck <groeck7@gmail.com> From: Guenter Roeck <linux@roeck-us.net> To: linux-hwmon@vger.kernel.org Cc: devicetree@vger.kernel.org, Rob Herring <robh@kernel.org>, Krzysztof Kozlowski <krzk+dt@kernel.org>, Conor Dooley <conor+dt@kernel.org>, linux-kernel@vger.kernel.org, Armin Wolf <W_Armin@gmx.de>, =?utf-8?q?Thomas?= =?utf-8?q?_Wei=C3=9Fschuh?= <linux@weissschuh.net>, =?utf-8?q?Ren=C3=A9_Reb?= =?utf-8?q?e?= <rene@exactcode.de>, Wolfram Sang <wsa+renesas@sang-engineering.com>, Guenter Roeck <linux@roeck-us.net> Subject: [PATCH RFT v3 4/4] hwmon: (spd5118) Add support for reading SPD data Date: Fri, 31 May 2024 16:05:56 -0700 Message-Id: <20240531230556.1409532-5-linux@roeck-us.net> In-Reply-To: <20240531230556.1409532-1-linux@roeck-us.net> References: <20240531230556.1409532-1-linux@roeck-us.net> Precedence: bulk MIME-Version: 1.0 Content-Transfer-Encoding: 8bit
Series	hwmon: Add support for SPD5118 compliant chips \| expand [v3,0/4] hwmon: Add support for SPD5118 compliant chips [v3,1/4] dt-bindings: trivial-devices: Add jedec,spd5118 [v3,2/4] hwmon: Add support for SPD5118 compliant temperature sensors [RFT,v3,3/4] hwmon: (spd5118) Add suspend/resume support [RFT,v3,4/4] hwmon: (spd5118) Add support for reading SPD data

diff --git a/Documentation/hwmon/spd5118.rst b/Documentation/hwmon/spd5118.rst index a15d75aa2066..ef7338f46575 100644 --- a/Documentation/hwmon/spd5118.rst +++ b/Documentation/hwmon/spd5118.rst @@ -53,3 +53,11 @@ temp1_crit_alarm Temperature critical alarm Alarm attributes are sticky until read and will be cleared afterwards unless the alarm condition still applies. + + +SPD (Serial Presence Detect) support +------------------------------------ + +The driver also supports reading the SPD NVRAM on SPD5118 compatible chips. +SPD data is available from the 'eeprom' binary attribute file attached to the +chip's I2C device. diff --git a/drivers/hwmon/spd5118.c b/drivers/hwmon/spd5118.c index baa315172298..131002290ff3 100644 --- a/drivers/hwmon/spd5118.c +++ b/drivers/hwmon/spd5118.c @@ -20,6 +20,8 @@ #include <linux/i2c.h> #include <linux/hwmon.h> #include <linux/module.h> +#include <linux/mutex.h> +#include <linux/nvmem-provider.h> #include <linux/pm.h> #include <linux/regmap.h> #include <linux/units.h> @@ -53,12 +55,31 @@ static const unsigned short normal_i2c[] = { #define SPD5118_TS_DISABLE BIT(0) /* temperature sensor disable */ +#define SPD5118_LEGACY_MODE_ADDR BIT(3) +#define SPD5118_LEGACY_PAGE_MASK GENMASK(2, 0) +#define SPD5118_LEGACY_MODE_MASK (SPD5118_LEGACY_MODE_ADDR | SPD5118_LEGACY_PAGE_MASK) + + +#define SPD5118_NUM_PAGES 8 +#define SPD5118_PAGE_SIZE 128 +#define SPD5118_PAGE_SHIFT 7 +#define SPD5118_PAGE_MASK GENMASK(6, 0) +#define SPD5118_EEPROM_BASE 0x80 +#define SPD5118_EEPROM_SIZE (SPD5118_PAGE_SIZE * SPD5118_NUM_PAGES) + /* 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 +struct spd5118_data { + struct regmap *regmap; + struct mutex nvmem_lock; +}; + +/* hwmon */ + static int spd5118_temp_from_reg(u16 reg) { int temp = sign_extend32(reg >> 2, 10); @@ -360,9 +381,111 @@ static const struct hwmon_chip_info spd5118_chip_info = { .info = spd5118_info, }; +/* nvmem */ + +static int spd5118_nvmem_set_page(struct regmap *regmap, int page) +{ + unsigned int old_page; + int err; + + err = regmap_read(regmap, SPD5118_REG_I2C_LEGACY_MODE, &old_page); + if (err) + return err; + + if (page != (old_page & SPD5118_LEGACY_MODE_MASK)) { + /* Update page and explicitly select 1-byte addressing */ + err = regmap_update_bits(regmap, SPD5118_REG_I2C_LEGACY_MODE, + SPD5118_LEGACY_MODE_MASK, page); + if (err) + return err; + + /* Selected new NVMEM page, drop cached data */ + regcache_drop_region(regmap, SPD5118_EEPROM_BASE, 0xff); + } + + return 0; +} + +static ssize_t spd5118_nvmem_read_page(struct regmap *regmap, char *buf, + unsigned int offset, size_t count) +{ + int err; + + err = spd5118_nvmem_set_page(regmap, offset >> SPD5118_PAGE_SHIFT); + if (err) + return err; + + offset &= SPD5118_PAGE_MASK; + + /* Can't cross page boundaries */ + if (offset + count > SPD5118_PAGE_SIZE) + count = SPD5118_PAGE_SIZE - offset; + + err = regmap_bulk_read(regmap, SPD5118_EEPROM_BASE + offset, buf, count); + if (err) + return err; + + return count; +} + +static int spd5118_nvmem_read(void *priv, unsigned int off, void *val, size_t count) +{ + struct spd5118_data *data = priv; + char *buf = val; + int ret; + + if (unlikely(!count)) + return count; + + if (off + count > SPD5118_EEPROM_SIZE) + return -EINVAL; + + mutex_lock(&data->nvmem_lock); + + while (count) { + ret = spd5118_nvmem_read_page(data->regmap, buf, off, count); + if (ret < 0) { + mutex_unlock(&data->nvmem_lock); + return ret; + } + buf += ret; + off += ret; + count -= ret; + } + mutex_unlock(&data->nvmem_lock); + return 0; +} + +static int spd5118_nvmem_init(struct device *dev, struct spd5118_data *data) +{ + struct nvmem_config nvmem_config = { + .type = NVMEM_TYPE_EEPROM, + .name = dev_name(dev), + .id = NVMEM_DEVID_AUTO, + .dev = dev, + .base_dev = dev, + .read_only = true, + .root_only = false, + .owner = THIS_MODULE, + .compat = true, + .reg_read = spd5118_nvmem_read, + .priv = data, + .stride = 1, + .word_size = 1, + .size = SPD5118_EEPROM_SIZE, + }; + struct nvmem_device *nvmem; + + nvmem = devm_nvmem_register(dev, &nvmem_config); + return PTR_ERR_OR_ZERO(nvmem); +} + +/* regmap */ + static bool spd5118_writeable_reg(struct device *dev, unsigned int reg) { switch (reg) { + case SPD5118_REG_I2C_LEGACY_MODE: case SPD5118_REG_TEMP_CLR: case SPD5118_REG_TEMP_CONFIG: case SPD5118_REG_TEMP_MAX: @@ -396,7 +519,7 @@ static bool spd5118_volatile_reg(struct device *dev, unsigned int reg) static const struct regmap_config spd5118_regmap_config = { .reg_bits = 8, .val_bits = 8, - .max_register = SPD5118_REG_TEMP_STATUS, + .max_register = 0xff, .writeable_reg = spd5118_writeable_reg, .volatile_reg = spd5118_volatile_reg, .cache_type = REGCACHE_MAPLE, @@ -406,10 +529,15 @@ static int spd5118_probe(struct i2c_client *client) { struct device *dev = &client->dev; unsigned int regval, revision, vendor, bank; + struct spd5118_data *data; struct device *hwmon_dev; struct regmap *regmap; int err; + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + 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"); @@ -433,7 +561,15 @@ static int spd5118_probe(struct i2c_client *client) if (!spd5118_vendor_valid(bank, vendor)) return -ENODEV; - dev_set_drvdata(dev, regmap); + data->regmap = regmap; + mutex_init(&data->nvmem_lock); + dev_set_drvdata(dev, data); + + err = spd5118_nvmem_init(dev, data); + if (err) { + dev_err_probe(dev, err, "failed to register nvmem\n"); + return err; + } hwmon_dev = devm_hwmon_device_register_with_info(dev, "spd5118", regmap, &spd5118_chip_info, @@ -454,7 +590,8 @@ static int spd5118_probe(struct i2c_client *client) static int spd5118_suspend(struct device *dev) { - struct regmap *regmap = dev_get_drvdata(dev); + struct spd5118_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; regcache_cache_bypass(regmap, true); regmap_update_bits(regmap, SPD5118_REG_TEMP_CONFIG, SPD5118_TS_DISABLE, @@ -469,7 +606,8 @@ static int spd5118_suspend(struct device *dev) static int spd5118_resume(struct device *dev) { - struct regmap *regmap = dev_get_drvdata(dev); + struct spd5118_data *data = dev_get_drvdata(dev); + struct regmap *regmap = data->regmap; regcache_cache_only(regmap, false); return regcache_sync(regmap);

[RFT,v3,4/4] hwmon: (spd5118) Add support for reading SPD data

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