// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Driver for MAX31730 3-Channel Remote Temperature Sensor
*
* Copyright (c) 2019 Guenter Roeck <linux@roeck-us.net>
*/
#include <linux/bits.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/hwmon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/slab.h>
/* Addresses scanned */
static const unsigned short normal_i2c[] = { 0x1c, 0x1d, 0x1e, 0x1f, 0x4c,
0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
/* The MAX31730 registers */
#define MAX31730_REG_TEMP 0x00
#define MAX31730_REG_CONF 0x13
#define MAX31730_STOP BIT(7)
#define MAX31730_EXTRANGE BIT(1)
#define MAX31730_REG_TEMP_OFFSET 0x16
#define MAX31730_TEMP_OFFSET_BASELINE 0x77
#define MAX31730_REG_OFFSET_ENABLE 0x17
#define MAX31730_REG_TEMP_MAX 0x20
#define MAX31730_REG_TEMP_MIN 0x30
#define MAX31730_REG_STATUS_HIGH 0x32
#define MAX31730_REG_STATUS_LOW 0x33
#define MAX31730_REG_CHANNEL_ENABLE 0x35
#define MAX31730_REG_TEMP_FAULT 0x36
#define MAX31730_REG_MFG_ID 0x50
#define MAX31730_MFG_ID 0x4d
#define MAX31730_REG_MFG_REV 0x51
#define MAX31730_MFG_REV 0x01
#define MAX31730_TEMP_MIN (-128000)
#define MAX31730_TEMP_MAX 127937
/* Each client has this additional data */
struct max31730_data {
struct i2c_client *client;
u8 orig_conf;
u8 current_conf;
u8 offset_enable;
u8 channel_enable;
};
/*-----------------------------------------------------------------------*/
static inline long max31730_reg_to_mc(s16 temp)
{
return DIV_ROUND_CLOSEST((temp >> 4) * 1000, 16);
}
static int max31730_write_config(struct max31730_data *data, u8 set_mask,
u8 clr_mask)
{
u8 value;
clr_mask |= MAX31730_EXTRANGE;
value = data->current_conf & ~clr_mask;
value |= set_mask;
if (data->current_conf != value) {
s32 err;
err = i2c_smbus_write_byte_data(data->client, MAX31730_REG_CONF,
value);
if (err)
return err;
data->current_conf = value;
}
return 0;
}
static int max31730_set_enable(struct i2c_client *client, int reg,
u8 *confdata, int channel, bool enable)
{
u8 regval = *confdata;
int err;
if (enable)
regval |= BIT(channel);
else
regval &= ~BIT(channel);
if (regval != *confdata) {
err = i2c_smbus_write_byte_data(client, reg, regval);
if (err)
return err;
*confdata = regval;
}
return 0;
}
static int max31730_set_offset_enable(struct max31730_data *data, int channel,
bool enable)
{
return max31730_set_enable(data->client, MAX31730_REG_OFFSET_ENABLE,
&data->offset_enable, channel, enable);
}
static int max31730_set_channel_enable(struct max31730_data *data, int channel,
bool enable)
{
return max31730_set_enable(data->client, MAX31730_REG_CHANNEL_ENABLE,
&data->channel_enable, channel, enable);
}
static int max31730_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
struct max31730_data *data = dev_get_drvdata(dev);
int regval, reg, offset;
if (type != hwmon_temp)
return -EINVAL;
switch (attr) {
case hwmon_temp_input:
if (!(data->channel_enable & BIT(channel)))
return -ENODATA;
reg = MAX31730_REG_TEMP + (channel * 2);
break;
case hwmon_temp_max:
reg = MAX31730_REG_TEMP_MAX + (channel * 2);
break;
case hwmon_temp_min:
reg = MAX31730_REG_TEMP_MIN;
break;
case hwmon_temp_enable:
*val = !!(data->channel_enable & BIT(channel));
return 0;
case hwmon_temp_offset:
if (!channel)
return -EINVAL;
if (!(data->offset_enable & BIT(channel))) {
*val = 0;
return 0;
}
offset = i2c_smbus_read_byte_data(data->client,
MAX31730_REG_TEMP_OFFSET);
if (offset < 0)
return offset;
*val = (offset - MAX31730_TEMP_OFFSET_BASELINE) * 125;
return 0;
case hwmon_temp_fault:
regval = i2c_smbus_read_byte_data(data->client,
MAX31730_REG_TEMP_FAULT);
if (regval < 0)
return regval;
*val = !!(regval & BIT(channel));
return 0;
case hwmon_temp_min_alarm:
regval = i2c_smbus_read_byte_data(data->client,
MAX31730_REG_STATUS_LOW);
if (regval < 0)
return regval;
*val = !!(regval & BIT(channel));
return 0;
case hwmon_temp_max_alarm:
regval = i2c_smbus_read_byte_data(data->client,
MAX31730_REG_STATUS_HIGH);
if (regval < 0)
return regval;
*val = !!(regval & BIT(channel));
return 0;
default:
return -EINVAL;
}
regval = i2c_smbus_read_word_swapped(data->client, reg);
if (regval < 0)
return regval;
*val = max31730_reg_to_mc(regval);
return 0;
}
static int max31730_write(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long val)
{
struct max31730_data *data = dev_get_drvdata(dev);
int reg, err;
if (type != hwmon_temp)
return -EINVAL;
switch (attr) {
case hwmon_temp_max:
reg = MAX31730_REG_TEMP_MAX + channel * 2;
break;
case hwmon_temp_min:
reg = MAX31730_REG_TEMP_MIN;
break;
case hwmon_temp_enable:
if (val != 0 && val != 1)
return -EINVAL;
return max31730_set_channel_enable(data, channel, val);
case hwmon_temp_offset:
val = clamp_val(val, -14875, 17000) + 14875;
val = DIV_ROUND_CLOSEST(val, 125);
err = max31730_set_offset_enable(data, channel,
val != MAX31730_TEMP_OFFSET_BASELINE);
if (err)
return err;
return i2c_smbus_write_byte_data(data->client,
MAX31730_REG_TEMP_OFFSET, val);
default:
return -EINVAL;
}
val = clamp_val(val, MAX31730_TEMP_MIN, MAX31730_TEMP_MAX);
val = DIV_ROUND_CLOSEST(val << 4, 1000) << 4;
return i2c_smbus_write_word_swapped(data->client, reg, (u16)val);
}
static umode_t max31730_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:
case hwmon_temp_min_alarm:
case hwmon_temp_max_alarm:
case hwmon_temp_fault:
return 0444;
case hwmon_temp_min:
return channel ? 0444 : 0644;
case hwmon_temp_offset:
case hwmon_temp_enable:
case hwmon_temp_max:
return 0644;
}
break;
default:
break;
}
return 0;
}
static const struct hwmon_channel_info * const max31730_info[] = {
HWMON_CHANNEL_INFO(chip,
HWMON_C_REGISTER_TZ),
HWMON_CHANNEL_INFO(temp,
HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
HWMON_T_ENABLE |
HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM,
HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
HWMON_T_OFFSET | HWMON_T_ENABLE |
HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
HWMON_T_FAULT,
HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
HWMON_T_OFFSET | HWMON_T_ENABLE |
HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
HWMON_T_FAULT,
HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX |
HWMON_T_OFFSET | HWMON_T_ENABLE |
HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
HWMON_T_FAULT
),
NULL
};
static const struct hwmon_ops max31730_hwmon_ops = {
.is_visible = max31730_is_visible,
.read = max31730_read,
.write = max31730_write,
};
static const struct hwmon_chip_info max31730_chip_info = {
.ops = &max31730_hwmon_ops,
.info = max31730_info,
};
static void max31730_remove(void *data)
{
struct max31730_data *max31730 = data;
struct i2c_client *client = max31730->client;
i2c_smbus_write_byte_data(client, MAX31730_REG_CONF,
max31730->orig_conf);
}
static int
max31730_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct device *hwmon_dev;
struct max31730_data *data;
int status, err;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
return -EIO;
data = devm_kzalloc(dev, sizeof(struct max31730_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = client;
/* Cache original configuration and enable status */
status = i2c_smbus_read_byte_data(client, MAX31730_REG_CHANNEL_ENABLE);
if (status < 0)
return status;
data->channel_enable = status;
status = i2c_smbus_read_byte_data(client, MAX31730_REG_OFFSET_ENABLE);
if (status < 0)
return status;
data->offset_enable = status;
status = i2c_smbus_read_byte_data(client, MAX31730_REG_CONF);
if (status < 0)
return status;
data->orig_conf = status;
data->current_conf = status;
err = max31730_write_config(data,
data->channel_enable ? 0 : MAX31730_STOP,
data->channel_enable ? MAX31730_STOP : 0);
if (err)
return err;
dev_set_drvdata(dev, data);
err = devm_add_action_or_reset(dev, max31730_remove, data);
if (err)
return err;
hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
data,
&max31730_chip_info,
NULL);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id max31730_ids[] = {
{ "max31730", 0, },
{ }
};
MODULE_DEVICE_TABLE(i2c, max31730_ids);
static const struct of_device_id __maybe_unused max31730_of_match[] = {
{
.compatible = "maxim,max31730",
},
{ },
};
MODULE_DEVICE_TABLE(of, max31730_of_match);
static bool max31730_check_reg_temp(struct i2c_client *client,
int reg)
{
int regval;
regval = i2c_smbus_read_byte_data(client, reg + 1);
return regval < 0 || (regval & 0x0f);
}
/* Return 0 if detection is successful, -ENODEV otherwise */
static int max31730_detect(struct i2c_client *client,
struct i2c_board_info *info)
{
struct i2c_adapter *adapter = client->adapter;
int regval;
int i;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
regval = i2c_smbus_read_byte_data(client, MAX31730_REG_MFG_ID);
if (regval != MAX31730_MFG_ID)
return -ENODEV;
regval = i2c_smbus_read_byte_data(client, MAX31730_REG_MFG_REV);
if (regval != MAX31730_MFG_REV)
return -ENODEV;
/* lower 4 bit of temperature and limit registers must be 0 */
if (max31730_check_reg_temp(client, MAX31730_REG_TEMP_MIN))
return -ENODEV;
for (i = 0; i < 4; i++) {
if (max31730_check_reg_temp(client, MAX31730_REG_TEMP + i * 2))
return -ENODEV;
if (max31730_check_reg_temp(client,
MAX31730_REG_TEMP_MAX + i * 2))
return -ENODEV;
}
strscpy(info->type, "max31730", I2C_NAME_SIZE);
return 0;
}
static int max31730_suspend(struct device *dev)
{
struct max31730_data *data = dev_get_drvdata(dev);
return max31730_write_config(data, MAX31730_STOP, 0);
}
static int max31730_resume(struct device *dev)
{
struct max31730_data *data = dev_get_drvdata(dev);
return max31730_write_config(data, 0, MAX31730_STOP);
}
static DEFINE_SIMPLE_DEV_PM_OPS(max31730_pm_ops, max31730_suspend, max31730_resume);
static struct i2c_driver max31730_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "max31730",
.of_match_table = of_match_ptr(max31730_of_match),
.pm = pm_sleep_ptr(&max31730_pm_ops),
},
.probe = max31730_probe,
.id_table = max31730_ids,
.detect = max31730_detect,
.address_list = normal_i2c,
};
module_i2c_driver(max31730_driver);
MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("MAX31730 driver");
MODULE_LICENSE("GPL");
