hwmon: (sbtsi) Add basic support for SB-TSI sensors (e7bb1a2a) · Commits · 戴 / test

drivers/hwmon/Kconfig

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Original line number	Diff line number	Diff line
		@@ -1533,6 +1533,16 @@ config SENSORS_SL28CPLD
		This driver can also be built as a module. If so, the module
		will be called sl28cpld-hwmon.

		config SENSORS_SBTSI
		tristate "Emulated SB-TSI temperature sensor"
		depends on I2C
		help
		If you say yes here you get support for emulated temperature
		sensors on AMD SoCs with SB-TSI interface connected to a BMC device.

		This driver can also be built as a module. If so, the module will
		be called sbtsi_temp.

		config SENSORS_SHT15
		tristate "Sensiron humidity and temperature sensors. SHT15 and compat."
		depends on GPIOLIB \|\| COMPILE_TEST

drivers/hwmon/Makefile

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Original line number	Diff line number	Diff line
		@@ -161,6 +161,7 @@ obj-$(CONFIG_SENSORS_POWR1220) += powr1220.o
		obj-$(CONFIG_SENSORS_PWM_FAN) += pwm-fan.o
		obj-$(CONFIG_SENSORS_RASPBERRYPI_HWMON) += raspberrypi-hwmon.o
		obj-$(CONFIG_SENSORS_S3C) += s3c-hwmon.o
		obj-$(CONFIG_SENSORS_SBTSI) += sbtsi_temp.o
		obj-$(CONFIG_SENSORS_SCH56XX_COMMON)+= sch56xx-common.o
		obj-$(CONFIG_SENSORS_SCH5627) += sch5627.o
		obj-$(CONFIG_SENSORS_SCH5636) += sch5636.o

drivers/hwmon/sbtsi_temp.c

0 → 100644

+250 −0

Original line number	Diff line number	Diff line
		// 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_device.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 *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,
		const struct i2c_device_id *id)
		{
		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", 0},
		{}
		};
		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 = {
		.class = I2C_CLASS_HWMON,
		.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");

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