drivers/hwmon/sbtsi_temp.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * sbtsi_temp.c - hwmon driver for a SBI Temperature Sensor Interface (SB-TSI)
  *                compliant AMD SoC temperature device.
  *
  * Copyright (c) 2020, Google Inc.
  * Copyright (c) 2020, Kun Yi <kunyi@google.com>
  */

 #include <linux/err.h>
 #include <linux/i2c.h>
 #include <linux/init.h>
 #include <linux/hwmon.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>

 /*
  * SB-TSI registers only support SMBus byte data access. "_INT" registers are
  * the integer part of a temperature value or limit, and "_DEC" registers are
  * corresponding decimal parts.
  */
 #define SBTSI_REG_TEMP_INT		0x01 /* RO */
 #define SBTSI_REG_STATUS		0x02 /* RO */
 #define SBTSI_REG_CONFIG		0x03 /* RO */
 #define SBTSI_REG_TEMP_HIGH_INT		0x07 /* RW */
 #define SBTSI_REG_TEMP_LOW_INT		0x08 /* RW */
 #define SBTSI_REG_TEMP_DEC		0x10 /* RW */
 #define SBTSI_REG_TEMP_HIGH_DEC		0x13 /* RW */
 #define SBTSI_REG_TEMP_LOW_DEC		0x14 /* RW */

 #define SBTSI_CONFIG_READ_ORDER_SHIFT	5

 #define SBTSI_TEMP_MIN	0
 #define SBTSI_TEMP_MAX	255875

 /* Each client has this additional data */
 struct sbtsi_data {
 	struct i2c_client *client;
 	struct mutex lock;
 };

 /*
  * From SB-TSI spec: CPU temperature readings and limit registers encode the
  * temperature in increments of 0.125 from 0 to 255.875. The "high byte"
  * register encodes the base-2 of the integer portion, and the upper 3 bits of
  * the "low byte" encode in base-2 the decimal portion.
  *
  * e.g. INT=0x19, DEC=0x20 represents 25.125 degrees Celsius
  *
  * Therefore temperature in millidegree Celsius =
  *   (INT + DEC / 256) * 1000 = (INT * 8 + DEC / 32) * 125
  */
 static inline int sbtsi_reg_to_mc(s32 integer, s32 decimal)
 {
 	return ((integer << 3) + (decimal >> 5)) * 125;
 }

 /*
  * Inversely, given temperature in millidegree Celsius
  *   INT = (TEMP / 125) / 8
  *   DEC = ((TEMP / 125) % 8) * 32
  * Caller have to make sure temp doesn't exceed 255875, the max valid value.
  */
 static inline void sbtsi_mc_to_reg(s32 temp, u8 *integer, u8 *decimal)
 {
 	temp /= 125;
 	*integer = temp >> 3;
 	*decimal = (temp & 0x7) << 5;
 }

 static int sbtsi_read(struct device *dev, enum hwmon_sensor_types type,
 		      u32 attr, int channel, long *val)
 {
 	struct sbtsi_data *data = dev_get_drvdata(dev);
 	s32 temp_int, temp_dec;
 	int err;

 	switch (attr) {
 	case hwmon_temp_input:
 		/*
 		 * ReadOrder bit specifies the reading order of integer and
 		 * decimal part of CPU temp for atomic reads. If bit == 0,
 		 * reading integer part triggers latching of the decimal part,
 		 * so integer part should be read first. If bit == 1, read
 		 * order should be reversed.
 		 */
 		err = i2c_smbus_read_byte_data(data->client, SBTSI_REG_CONFIG);
 		if (err < 0)
 			return err;

 		mutex_lock(&data->lock);
 		if (err & BIT(SBTSI_CONFIG_READ_ORDER_SHIFT)) {
 			temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_DEC);
 			temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_INT);
 		} else {
 			temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_INT);
 			temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_DEC);
 		}
 		mutex_unlock(&data->lock);
 		break;
 	case hwmon_temp_max:
 		mutex_lock(&data->lock);
 		temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_HIGH_INT);
 		temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_HIGH_DEC);
 		mutex_unlock(&data->lock);
 		break;
 	case hwmon_temp_min:
 		mutex_lock(&data->lock);
 		temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_LOW_INT);
 		temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_LOW_DEC);
 		mutex_unlock(&data->lock);
 		break;
 	default:
 		return -EINVAL;
 	}


 	if (temp_int < 0)
 		return temp_int;
 	if (temp_dec < 0)
 		return temp_dec;

 	*val = sbtsi_reg_to_mc(temp_int, temp_dec);

 	return 0;
 }

 static int sbtsi_write(struct device *dev, enum hwmon_sensor_types type,
 		       u32 attr, int channel, long val)
 {
 	struct sbtsi_data *data = dev_get_drvdata(dev);
 	int reg_int, reg_dec, err;
 	u8 temp_int, temp_dec;

 	switch (attr) {
 	case hwmon_temp_max:
 		reg_int = SBTSI_REG_TEMP_HIGH_INT;
 		reg_dec = SBTSI_REG_TEMP_HIGH_DEC;
 		break;
 	case hwmon_temp_min:
 		reg_int = SBTSI_REG_TEMP_LOW_INT;
 		reg_dec = SBTSI_REG_TEMP_LOW_DEC;
 		break;
 	default:
 		return -EINVAL;
 	}

 	val = clamp_val(val, SBTSI_TEMP_MIN, SBTSI_TEMP_MAX);
 	sbtsi_mc_to_reg(val, &temp_int, &temp_dec);

 	mutex_lock(&data->lock);
 	err = i2c_smbus_write_byte_data(data->client, reg_int, temp_int);
 	if (err)
 		goto exit;

 	err = i2c_smbus_write_byte_data(data->client, reg_dec, temp_dec);
 exit:
 	mutex_unlock(&data->lock);
 	return err;
 }

 static umode_t sbtsi_is_visible(const void *data,
 				enum hwmon_sensor_types type,
 				u32 attr, int channel)
 {
 	switch (type) {
 	case hwmon_temp:
 		switch (attr) {
 		case hwmon_temp_input:
 			return 0444;
 		case hwmon_temp_min:
 			return 0644;
 		case hwmon_temp_max:
 			return 0644;
 		}
 		break;
 	default:
 		break;
 	}
 	return 0;
 }

 static const struct hwmon_channel_info * const sbtsi_info[] = {
 	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
 	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX),
 	NULL
 };

 static const struct hwmon_ops sbtsi_hwmon_ops = {
 	.is_visible = sbtsi_is_visible,
 	.read = sbtsi_read,
 	.write = sbtsi_write,
 };

 static const struct hwmon_chip_info sbtsi_chip_info = {
 	.ops = &sbtsi_hwmon_ops,
 	.info = sbtsi_info,
 };

 static int sbtsi_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;
 	struct device *hwmon_dev;
 	struct sbtsi_data *data;

 	data = devm_kzalloc(dev, sizeof(struct sbtsi_data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;

 	data->client = client;
 	mutex_init(&data->lock);

 	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data, &sbtsi_chip_info,
 							 NULL);

 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }

 static const struct i2c_device_id sbtsi_id[] = {
 	{"sbtsi"},
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, sbtsi_id);

 static const struct of_device_id __maybe_unused sbtsi_of_match[] = {
 	{
 		.compatible = "amd,sbtsi",
 	},
 	{ },
 };
 MODULE_DEVICE_TABLE(of, sbtsi_of_match);

 static struct i2c_driver sbtsi_driver = {
 	.driver = {
 		.name = "sbtsi",
 		.of_match_table = of_match_ptr(sbtsi_of_match),
 	},
 	.probe = sbtsi_probe,
 	.id_table = sbtsi_id,
 };

 module_i2c_driver(sbtsi_driver);

 MODULE_AUTHOR("Kun Yi <kunyi@google.com>");
 MODULE_DESCRIPTION("Hwmon driver for AMD SB-TSI emulated sensor");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* sbtsi_temp.c - hwmon driver for a SBI Temperature Sensor Interface (SB-TSI)
	* compliant AMD SoC temperature device.
	*
	* Copyright (c) 2020, Google Inc.
	* Copyright (c) 2020, Kun Yi <kunyi@google.com>
	*/

	#include <linux/err.h>
	#include <linux/i2c.h>
	#include <linux/init.h>
	#include <linux/hwmon.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of.h>

	/*
	* SB-TSI registers only support SMBus byte data access. "_INT" registers are
	* the integer part of a temperature value or limit, and "_DEC" registers are
	* corresponding decimal parts.
	*/
	#define SBTSI_REG_TEMP_INT 0x01 /* RO */
	#define SBTSI_REG_STATUS 0x02 /* RO */
	#define SBTSI_REG_CONFIG 0x03 /* RO */
	#define SBTSI_REG_TEMP_HIGH_INT 0x07 /* RW */
	#define SBTSI_REG_TEMP_LOW_INT 0x08 /* RW */
	#define SBTSI_REG_TEMP_DEC 0x10 /* RW */
	#define SBTSI_REG_TEMP_HIGH_DEC 0x13 /* RW */
	#define SBTSI_REG_TEMP_LOW_DEC 0x14 /* RW */

	#define SBTSI_CONFIG_READ_ORDER_SHIFT 5

	#define SBTSI_TEMP_MIN 0
	#define SBTSI_TEMP_MAX 255875

	/* Each client has this additional data */
	struct sbtsi_data {
	struct i2c_client *client;
	struct mutex lock;
	};

	/*
	* From SB-TSI spec: CPU temperature readings and limit registers encode the
	* temperature in increments of 0.125 from 0 to 255.875. The "high byte"
	* register encodes the base-2 of the integer portion, and the upper 3 bits of
	* the "low byte" encode in base-2 the decimal portion.
	*
	* e.g. INT=0x19, DEC=0x20 represents 25.125 degrees Celsius
	*
	* Therefore temperature in millidegree Celsius =
	* (INT + DEC / 256) * 1000 = (INT * 8 + DEC / 32) * 125
	*/
	static inline int sbtsi_reg_to_mc(s32 integer, s32 decimal)
	{
	return ((integer << 3) + (decimal >> 5)) * 125;
	}

	/*
	* Inversely, given temperature in millidegree Celsius
	* INT = (TEMP / 125) / 8
	* DEC = ((TEMP / 125) % 8) * 32
	* Caller have to make sure temp doesn't exceed 255875, the max valid value.
	*/
	static inline void sbtsi_mc_to_reg(s32 temp, u8 integer, u8 decimal)
	{
	temp /= 125;
	*integer = temp >> 3;
	*decimal = (temp & 0x7) << 5;
	}

	static int sbtsi_read(struct device *dev, enum hwmon_sensor_types type,
	u32 attr, int channel, long *val)
	{
	struct sbtsi_data *data = dev_get_drvdata(dev);
	s32 temp_int, temp_dec;
	int err;

	switch (attr) {
	case hwmon_temp_input:
	/*
	* ReadOrder bit specifies the reading order of integer and
	* decimal part of CPU temp for atomic reads. If bit == 0,
	* reading integer part triggers latching of the decimal part,
	* so integer part should be read first. If bit == 1, read
	* order should be reversed.
	*/
	err = i2c_smbus_read_byte_data(data->client, SBTSI_REG_CONFIG);
	if (err < 0)
	return err;

	mutex_lock(&data->lock);
	if (err & BIT(SBTSI_CONFIG_READ_ORDER_SHIFT)) {
	temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_DEC);
	temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_INT);
	} else {
	temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_INT);
	temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_DEC);
	}
	mutex_unlock(&data->lock);
	break;
	case hwmon_temp_max:
	mutex_lock(&data->lock);
	temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_HIGH_INT);
	temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_HIGH_DEC);
	mutex_unlock(&data->lock);
	break;
	case hwmon_temp_min:
	mutex_lock(&data->lock);
	temp_int = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_LOW_INT);
	temp_dec = i2c_smbus_read_byte_data(data->client, SBTSI_REG_TEMP_LOW_DEC);
	mutex_unlock(&data->lock);
	break;
	default:
	return -EINVAL;
	}


	if (temp_int < 0)
	return temp_int;
	if (temp_dec < 0)
	return temp_dec;

	*val = sbtsi_reg_to_mc(temp_int, temp_dec);

	return 0;
	}

	static int sbtsi_write(struct device *dev, enum hwmon_sensor_types type,
	u32 attr, int channel, long val)
	{
	struct sbtsi_data *data = dev_get_drvdata(dev);
	int reg_int, reg_dec, err;
	u8 temp_int, temp_dec;

	switch (attr) {
	case hwmon_temp_max:
	reg_int = SBTSI_REG_TEMP_HIGH_INT;
	reg_dec = SBTSI_REG_TEMP_HIGH_DEC;
	break;
	case hwmon_temp_min:
	reg_int = SBTSI_REG_TEMP_LOW_INT;
	reg_dec = SBTSI_REG_TEMP_LOW_DEC;
	break;
	default:
	return -EINVAL;
	}

	val = clamp_val(val, SBTSI_TEMP_MIN, SBTSI_TEMP_MAX);
	sbtsi_mc_to_reg(val, &temp_int, &temp_dec);

	mutex_lock(&data->lock);
	err = i2c_smbus_write_byte_data(data->client, reg_int, temp_int);
	if (err)
	goto exit;

	err = i2c_smbus_write_byte_data(data->client, reg_dec, temp_dec);
	exit:
	mutex_unlock(&data->lock);
	return err;
	}

	static umode_t sbtsi_is_visible(const void *data,
	enum hwmon_sensor_types type,
	u32 attr, int channel)
	{
	switch (type) {
	case hwmon_temp:
	switch (attr) {
	case hwmon_temp_input:
	return 0444;
	case hwmon_temp_min:
	return 0644;
	case hwmon_temp_max:
	return 0644;
	}
	break;
	default:
	break;
	}
	return 0;
	}

	static const struct hwmon_channel_info * const sbtsi_info[] = {
	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT \| HWMON_T_MIN \| HWMON_T_MAX),
	NULL
	};

	static const struct hwmon_ops sbtsi_hwmon_ops = {
	.is_visible = sbtsi_is_visible,
	.read = sbtsi_read,
	.write = sbtsi_write,
	};

	static const struct hwmon_chip_info sbtsi_chip_info = {
	.ops = &sbtsi_hwmon_ops,
	.info = sbtsi_info,
	};

	static int sbtsi_probe(struct i2c_client *client)
	{
	struct device *dev = &client->dev;
	struct device *hwmon_dev;
	struct sbtsi_data *data;

	data = devm_kzalloc(dev, sizeof(struct sbtsi_data), GFP_KERNEL);
	if (!data)
	return -ENOMEM;

	data->client = client;
	mutex_init(&data->lock);

	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data, &sbtsi_chip_info,
	NULL);

	return PTR_ERR_OR_ZERO(hwmon_dev);
	}

	static const struct i2c_device_id sbtsi_id[] = {
	{"sbtsi"},
	{}
	};
	MODULE_DEVICE_TABLE(i2c, sbtsi_id);

	static const struct of_device_id __maybe_unused sbtsi_of_match[] = {
	{
	.compatible = "amd,sbtsi",
	},
	{ },
	};
	MODULE_DEVICE_TABLE(of, sbtsi_of_match);

	static struct i2c_driver sbtsi_driver = {
	.driver = {
	.name = "sbtsi",
	.of_match_table = of_match_ptr(sbtsi_of_match),
	},
	.probe = sbtsi_probe,
	.id_table = sbtsi_id,
	};

	module_i2c_driver(sbtsi_driver);

	MODULE_AUTHOR("Kun Yi <kunyi@google.com>");
	MODULE_DESCRIPTION("Hwmon driver for AMD SB-TSI emulated sensor");
	MODULE_LICENSE("GPL");