| SB Temperature Sensor Interface (SB-TSI) is an SMBus compatible |
| interface that reports AMD SoC's Ttcl (normalized temperature), |
| and resembles a typical 8-pin remote temperature sensor's I2C interface |
| to BMC. |
| |
| This commit adds basic support using this interface to read CPU |
| temperature, and read/write high/low CPU temp thresholds. |
| |
| To instantiate this driver on an AMD CPU with SB-TSI |
| support, the i2c bus number would be the bus connected from the board |
| management controller (BMC) to the CPU. The i2c address is specified in |
| Section 6.3.1 of the spec [1]: The SB-TSI address is normally 98h for socket 0 |
| and 90h for socket 1, but it could vary based on hardware address select pins. |
| |
| [1]: https://www.amd.com/system/files/TechDocs/56255_OSRR.pdf |
| |
| Test status: tested reading temp1_input, and reading/writing |
| temp1_max/min. |
| |
| Signed-off-by: Kun Yi <kunyi at google.com> |
| --- |
| drivers/hwmon/Kconfig | 10 ++ |
| drivers/hwmon/Makefile | 1 + |
| drivers/hwmon/sbtsi_temp.c | 259 +++++++++++++++++++++++++++++++++++++ |
| 3 files changed, 270 insertions(+) |
| create mode 100644 drivers/hwmon/sbtsi_temp.c |
| |
| diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig |
| index 05a30832c6ba..9585dcd01d1b 100644 |
| --- a/drivers/hwmon/Kconfig |
| +++ b/drivers/hwmon/Kconfig |
| @@ -1412,6 +1412,16 @@ config SENSORS_RASPBERRYPI_HWMON |
| This driver can also be built as a module. If so, the module |
| will be called raspberrypi-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 |
| diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile |
| index b0b9c8e57176..cd109f003ce4 100644 |
| --- a/drivers/hwmon/Makefile |
| +++ b/drivers/hwmon/Makefile |
| @@ -152,6 +152,7 @@ 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 |
| diff --git a/drivers/hwmon/sbtsi_temp.c b/drivers/hwmon/sbtsi_temp.c |
| new file mode 100644 |
| index 000000000000..e3ad6a9f7ec1 |
| --- /dev/null |
| +++ b/drivers/hwmon/sbtsi_temp.c |
| @@ -0,0 +1,259 @@ |
| +// 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 at 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_REG_REV 0xFF /* RO */ |
| + |
| +#define SBTSI_CONFIG_READ_ORDER_SHIFT 5 |
| + |
| +#define SBTSI_TEMP_MIN 0 |
| +#define SBTSI_TEMP_MAX 255875 |
| +#define SBTSI_REV_MAX_VALID_ID 4 |
| + |
| +/* 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, reg_int, reg_dec; |
| + u8 read_order; |
| + |
| + if (type != hwmon_temp) |
| + return -EINVAL; |
| + |
| + read_order = 0; |
| + 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; |
| + |
| + read_order = (u8)err & BIT(SBTSI_CONFIG_READ_ORDER_SHIFT); |
| + reg_int = SBTSI_REG_TEMP_INT; |
| + reg_dec = SBTSI_REG_TEMP_DEC; |
| + break; |
| + 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; |
| + } |
| + |
| + if (read_order == 0) { |
| + temp_int = i2c_smbus_read_byte_data(data->client, reg_int); |
| + temp_dec = i2c_smbus_read_byte_data(data->client, reg_dec); |
| + } else { |
| + temp_dec = i2c_smbus_read_byte_data(data->client, reg_dec); |
| + temp_int = i2c_smbus_read_byte_data(data->client, reg_int); |
| + } |
| + |
| + 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; |
| + |
| + if (type != hwmon_temp) |
| + return -EINVAL; |
| + |
| + 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); |
| + mutex_lock(&data->lock); |
| + sbtsi_mc_to_reg(val, &temp_int, &temp_dec); |
| + 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 at google.com>"); |
| +MODULE_DESCRIPTION("Hwmon driver for AMD SB-TSI emulated sensor"); |
| +MODULE_LICENSE("GPL"); |
| -- |
| 2.26.0.292.g33ef6b2f38-goog |