// SPDX-License-Identifier: GPL-2.0-or-later
/*
* lm92 - Hardware monitoring driver
* Copyright (C) 2005-2008 Jean Delvare <[email protected]>
*
* Based on the lm90 driver, with some ideas taken from the lm_sensors
* lm92 driver as well.
*
* The LM92 is a sensor chip made by National Semiconductor. It reports
* its own temperature with a 0.0625 deg resolution and a 0.33 deg
* accuracy. Complete datasheet can be obtained from National's website
* at:
* http://www.national.com/pf/LM/LM92.html
*
* This driver also supports the MAX6635 sensor chip made by Maxim.
* This chip is compatible with the LM92, but has a lesser accuracy
* (1.0 deg). Complete datasheet can be obtained from Maxim's website
* at:
* http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
*
* Since the LM92 was the first chipset supported by this driver, most
* comments will refer to this chipset, but are actually general and
* concern all supported chipsets, unless mentioned otherwise.
*
* Support could easily be added for the National Semiconductor LM76
* and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
* with the LM92.
*/
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/regmap.h>
#include <linux/slab.h>
/*
* The LM92 and MAX6635 have 2 two-state pins for address selection,
* resulting in 4 possible addresses.
*/
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
I2C_CLIENT_END };
/* The LM92 registers */
#define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
#define LM92_REG_TEMP 0x00 /* 16-bit, RO */
#define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
#define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
#define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
#define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
#define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
/*
* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
* left-justified in 16-bit registers. No rounding is done, with such
* a resolution it's just not worth it. Note that the MAX6635 doesn't
* make use of the 4 lower bits for limits (i.e. effective resolution
* for limits is 1 degree Celsius).
*/
static inline int TEMP_FROM_REG(s16 reg)
{
return reg / 8 * 625 / 10;
}
static inline s16 TEMP_TO_REG(long val, int resolution)
{
val = clamp_val(val, -60000, 160000);
return DIV_ROUND_CLOSEST(val << (resolution - 9), 1000) << (16 - resolution);
}
/* Alarm flags are stored in the 3 LSB of the temperature register */
static inline u8 ALARMS_FROM_REG(s16 reg)
{
return reg & 0x0007;
}
/* Client data (each client gets its own) */
struct lm92_data {
struct regmap *regmap;
struct mutex update_lock;
int resolution;
};
static int lm92_temp_read(struct lm92_data *data, u32 attr, int channel, long *val)
{
int reg = -1, hyst_reg = -1, alarm_bit = 0;
struct regmap *regmap = data->regmap;
u32 temp;
int ret;
switch (attr) {
case hwmon_temp_input:
reg = LM92_REG_TEMP;
break;
case hwmon_temp_min:
reg = LM92_REG_TEMP_LOW;
break;
case hwmon_temp_max:
reg = LM92_REG_TEMP_HIGH;
break;
case hwmon_temp_crit:
reg = LM92_REG_TEMP_CRIT;
break;
case hwmon_temp_min_hyst:
hyst_reg = LM92_REG_TEMP_LOW;
break;
case hwmon_temp_max_hyst:
hyst_reg = LM92_REG_TEMP_HIGH;
break;
case hwmon_temp_crit_hyst:
hyst_reg = LM92_REG_TEMP_CRIT;
break;
case hwmon_temp_min_alarm:
alarm_bit = 0;
break;
case hwmon_temp_max_alarm:
alarm_bit = 1;
break;
case hwmon_temp_crit_alarm:
alarm_bit = 2;
break;
default:
return -EOPNOTSUPP;
}
if (reg >= 0) {
ret = regmap_read(regmap, reg, &temp);
if (ret < 0)
return ret;
*val = TEMP_FROM_REG(temp);
} else if (hyst_reg >= 0) {
u32 regs[2] = { hyst_reg, LM92_REG_TEMP_HYST };
u16 regvals[2];
ret = regmap_multi_reg_read(regmap, regs, regvals, 2);
if (ret)
return ret;
if (attr == hwmon_temp_min_hyst)
*val = TEMP_FROM_REG(regvals[0]) + TEMP_FROM_REG(regvals[1]);
else
*val = TEMP_FROM_REG(regvals[0]) - TEMP_FROM_REG(regvals[1]);
} else {
ret = regmap_read(regmap, LM92_REG_TEMP, &temp);
if (ret)
return ret;
*val = !!(temp & BIT(alarm_bit));
}
return 0;
}
static int lm92_chip_read(struct lm92_data *data, u32 attr, long *val)
{
u32 temp;
int ret;
switch (attr) {
case hwmon_chip_alarms:
ret = regmap_read(data->regmap, LM92_REG_TEMP, &temp);
if (ret)
return ret;
*val = ALARMS_FROM_REG(temp);
break;
default:
return -EOPNOTSUPP;
}
return 0;
}
static int lm92_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
int channel, long *val)
{
struct lm92_data *data = dev_get_drvdata(dev);
switch (type) {
case hwmon_chip:
return lm92_chip_read(data, attr, val);
case hwmon_temp:
return lm92_temp_read(data, attr, channel, val);
default:
return -EOPNOTSUPP;
}
}
static int lm92_temp_write(struct lm92_data *data, u32 attr, long val)
{
struct regmap *regmap = data->regmap;
int reg, err;
u32 temp;
switch (attr) {
case hwmon_temp_min:
reg = LM92_REG_TEMP_LOW;
break;
case hwmon_temp_max:
reg = LM92_REG_TEMP_HIGH;
break;
case hwmon_temp_crit:
reg = LM92_REG_TEMP_CRIT;
break;
case hwmon_temp_crit_hyst:
val = clamp_val(val, -120000, 220000);
mutex_lock(&data->update_lock);
err = regmap_read(regmap, LM92_REG_TEMP_CRIT, &temp);
if (err)
goto unlock;
val = TEMP_TO_REG(TEMP_FROM_REG(temp) - val, data->resolution);
err = regmap_write(regmap, LM92_REG_TEMP_HYST, val);
unlock:
mutex_unlock(&data->update_lock);
return err;
default:
return -EOPNOTSUPP;
}
return regmap_write(regmap, reg, TEMP_TO_REG(val, data->resolution));
}
static int lm92_write(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long val)
{
struct lm92_data *data = dev_get_drvdata(dev);
switch (type) {
case hwmon_temp:
return lm92_temp_write(data, attr, val);
default:
return -EOPNOTSUPP;
}
}
static umode_t lm92_is_visible(const void *_data, enum hwmon_sensor_types type,
u32 attr, int channel)
{
switch (type) {
case hwmon_chip:
switch (attr) {
case hwmon_chip_alarms:
return 0444;
default:
break;
}
break;
case hwmon_temp:
switch (attr) {
case hwmon_temp_min:
case hwmon_temp_max:
case hwmon_temp_crit:
case hwmon_temp_crit_hyst:
return 0644;
case hwmon_temp_input:
case hwmon_temp_min_hyst:
case hwmon_temp_max_hyst:
case hwmon_temp_min_alarm:
case hwmon_temp_max_alarm:
case hwmon_temp_crit_alarm:
return 0444;
default:
break;
}
break;
default:
break;
}
return 0;
}
static const struct hwmon_channel_info * const lm92_info[] = {
HWMON_CHANNEL_INFO(chip, HWMON_C_ALARMS),
HWMON_CHANNEL_INFO(temp,
HWMON_T_INPUT |
HWMON_T_MIN | HWMON_T_MIN_HYST |
HWMON_T_MAX | HWMON_T_MAX_HYST |
HWMON_T_CRIT | HWMON_T_CRIT_HYST |
HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM |
HWMON_T_CRIT_ALARM),
NULL
};
static const struct hwmon_ops lm92_hwmon_ops = {
.is_visible = lm92_is_visible,
.read = lm92_read,
.write = lm92_write,
};
static const struct hwmon_chip_info lm92_chip_info = {
.ops = &lm92_hwmon_ops,
.info = lm92_info,
};
/*
* Detection and registration
*/
static int lm92_init_client(struct regmap *regmap)
{
return regmap_clear_bits(regmap, LM92_REG_CONFIG, 0x01);
}
/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm92_detect(struct i2c_client *new_client,
struct i2c_board_info *info)
{
struct i2c_adapter *adapter = new_client->adapter;
u8 config_addr = LM92_REG_CONFIG;
u8 man_id_addr = LM92_REG_MAN_ID;
int i, regval;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
| I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
/*
* Register values repeat with multiples of 8.
* Read twice to improve detection accuracy.
*/
for (i = 0; i < 2; i++) {
regval = i2c_smbus_read_word_data(new_client, man_id_addr);
if (regval != 0x0180)
return -ENODEV;
regval = i2c_smbus_read_byte_data(new_client, config_addr);
if (regval < 0 || (regval & 0xe0))
return -ENODEV;
config_addr += 8;
man_id_addr += 8;
}
strscpy(info->type, "lm92", I2C_NAME_SIZE);
return 0;
}
/* regmap */
static int lm92_reg_read(void *context, unsigned int reg, unsigned int *val)
{
int ret;
if (reg == LM92_REG_CONFIG)
ret = i2c_smbus_read_byte_data(context, reg);
else
ret = i2c_smbus_read_word_swapped(context, reg);
if (ret < 0)
return ret;
*val = ret;
return 0;
}
static int lm92_reg_write(void *context, unsigned int reg, unsigned int val)
{
if (reg == LM92_REG_CONFIG)
return i2c_smbus_write_byte_data(context, LM92_REG_CONFIG, val);
return i2c_smbus_write_word_swapped(context, reg, val);
}
static bool lm92_regmap_is_volatile(struct device *dev, unsigned int reg)
{
return reg == LM92_REG_TEMP;
}
static bool lm92_regmap_is_writeable(struct device *dev, unsigned int reg)
{
return reg >= LM92_REG_CONFIG;
}
static const struct regmap_config lm92_regmap_config = {
.reg_bits = 8,
.val_bits = 16,
.max_register = LM92_REG_TEMP_HIGH,
.cache_type = REGCACHE_MAPLE,
.volatile_reg = lm92_regmap_is_volatile,
.writeable_reg = lm92_regmap_is_writeable,
};
static const struct regmap_bus lm92_regmap_bus = {
.reg_write = lm92_reg_write,
.reg_read = lm92_reg_read,
};
static int lm92_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct device *hwmon_dev;
struct lm92_data *data;
struct regmap *regmap;
int err;
regmap = devm_regmap_init(dev, &lm92_regmap_bus, client,
&lm92_regmap_config);
if (IS_ERR(regmap))
return PTR_ERR(regmap);
data = devm_kzalloc(dev, sizeof(struct lm92_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->regmap = regmap;
data->resolution = (unsigned long)i2c_get_match_data(client);
mutex_init(&data->update_lock);
/* Initialize the chipset */
err = lm92_init_client(regmap);
if (err)
return err;
hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
&lm92_chip_info, NULL);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
/*
* Module and driver stuff
*/
/* .driver_data is limit register resolution */
static const struct i2c_device_id lm92_id[] = {
{ "lm92", 13 },
{ "max6635", 9 },
{ }
};
MODULE_DEVICE_TABLE(i2c, lm92_id);
static struct i2c_driver lm92_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "lm92",
},
.probe = lm92_probe,
.id_table = lm92_id,
.detect = lm92_detect,
.address_list = normal_i2c,
};
module_i2c_driver(lm92_driver);
MODULE_AUTHOR("Jean Delvare <[email protected]>");
MODULE_DESCRIPTION("LM92/MAX6635 driver");
MODULE_LICENSE("GPL");
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