forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
250 lines
6.4 KiB
250 lines
6.4 KiB
// 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 <[email protected]> |
|
*/ |
|
|
|
#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 <[email protected]>"); |
|
MODULE_DESCRIPTION("Hwmon driver for AMD SB-TSI emulated sensor"); |
|
MODULE_LICENSE("GPL");
|
|
|