Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-29 15:41:36 +00:00
Code Issues Packages Projects Releases Wiki Activity
b54c4b02ab
linux/drivers/hwmon/max31827.c
Daniel Matyas 16d60ba8fd hwmon: Add MAX31827 driver 
MAX31827 is a low-power temperature switch with I2C interface.

The device is a ±1°C accuracy from -40°C to +125°C
(12 bits) local temperature switch and sensor with I2C/SM-
Bus interface. The combination of small 6-bump wafer-lev-
el package (WLP) and high accuracy makes this temper-
ature sensor/switch ideal for a wide range of applications.

Signed-off-by: Daniel Matyas <daniel.matyas@analog.com>
Link: https://lore.kernel.org/r/20230524160131.14081-2-daniel.matyas@analog.com
[groeck: Improved define alignment, return -EINVAL after bad user input,
 fixed up compatible statement]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2023-06-08 06:41:18 -07:00

467 lines
10 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0
/*
* max31827.c - Support for Maxim Low-Power Switch
*
* Copyright (c) 2023 Daniel Matyas <daniel.matyas@analog.com>
*/
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/hwmon.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/regmap.h>
#define MAX31827_T_REG 0x0
#define MAX31827_CONFIGURATION_REG 0x2
#define MAX31827_TH_REG 0x4
#define MAX31827_TL_REG 0x6
#define MAX31827_TH_HYST_REG 0x8
#define MAX31827_TL_HYST_REG 0xA
#define MAX31827_CONFIGURATION_1SHOT_MASK BIT(0)
#define MAX31827_CONFIGURATION_CNV_RATE_MASK GENMASK(3, 1)
#define MAX31827_CONFIGURATION_U_TEMP_STAT_MASK BIT(14)
#define MAX31827_CONFIGURATION_O_TEMP_STAT_MASK BIT(15)
#define MAX31827_12_BIT_CNV_TIME 141
#define MAX31827_CNV_1_DIV_64_HZ 0x1
#define MAX31827_CNV_1_DIV_32_HZ 0x2
#define MAX31827_CNV_1_DIV_16_HZ 0x3
#define MAX31827_CNV_1_DIV_4_HZ 0x4
#define MAX31827_CNV_1_HZ 0x5
#define MAX31827_CNV_4_HZ 0x6
#define MAX31827_CNV_8_HZ 0x7
#define MAX31827_16_BIT_TO_M_DGR(x) (sign_extend32(x, 15) * 1000 / 16)
#define MAX31827_M_DGR_TO_16_BIT(x) (((x) << 4) / 1000)
#define MAX31827_DEVICE_ENABLE(x) ((x) ? 0xA : 0x0)
struct max31827_state {
/*
* Prevent simultaneous access to the i2c client.
*/
struct mutex lock;
struct regmap *regmap;
bool enable;
};
static const struct regmap_config max31827_regmap = {
.reg_bits = 8,
.val_bits = 16,
.max_register = 0xA,
};
static int write_alarm_val(struct max31827_state *st, unsigned int reg,
long val)
{
unsigned int cfg;
unsigned int tmp;
int ret;
val = MAX31827_M_DGR_TO_16_BIT(val);
/*
* Before the Temperature Threshold Alarm and Alarm Hysteresis Threshold
* register values are changed over I2C, the part must be in shutdown
* mode.
*
* Mutex is used to ensure, that some other process doesn't change the
* configuration register.
*/
mutex_lock(&st->lock);
if (!st->enable) {
ret = regmap_write(st->regmap, reg, val);
goto unlock;
}
ret = regmap_read(st->regmap, MAX31827_CONFIGURATION_REG, &cfg);
if (ret)
goto unlock;
tmp = cfg & ~(MAX31827_CONFIGURATION_1SHOT_MASK |
MAX31827_CONFIGURATION_CNV_RATE_MASK);
ret = regmap_write(st->regmap, MAX31827_CONFIGURATION_REG, tmp);
if (ret)
goto unlock;
ret = regmap_write(st->regmap, reg, val);
if (ret)
goto unlock;
ret = regmap_write(st->regmap, MAX31827_CONFIGURATION_REG, cfg);
unlock:
mutex_unlock(&st->lock);
return ret;
}
static umode_t max31827_is_visible(const void *state,
enum hwmon_sensor_types type, u32 attr,
int channel)
{
if (type == hwmon_temp) {
switch (attr) {
case hwmon_temp_enable:
case hwmon_temp_max:
case hwmon_temp_min:
case hwmon_temp_max_hyst:
case hwmon_temp_min_hyst:
return 0644;
case hwmon_temp_input:
case hwmon_temp_min_alarm:
case hwmon_temp_max_alarm:
return 0444;
default:
return 0;
}
} else if (type == hwmon_chip) {
if (attr == hwmon_chip_update_interval)
return 0644;
}
return 0;
}
static int max31827_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
struct max31827_state *st = dev_get_drvdata(dev);
unsigned int uval;
int ret = 0;
switch (type) {
case hwmon_temp:
switch (attr) {
case hwmon_temp_enable:
ret = regmap_read(st->regmap,
MAX31827_CONFIGURATION_REG, &uval);
if (ret)
break;
uval = FIELD_GET(MAX31827_CONFIGURATION_1SHOT_MASK |
MAX31827_CONFIGURATION_CNV_RATE_MASK,
uval);
*val = !!uval;
break;
case hwmon_temp_input:
mutex_lock(&st->lock);
if (!st->enable) {
/*
* This operation requires mutex protection,
* because the chip configuration should not
* be changed during the conversion process.
*/
ret = regmap_update_bits(st->regmap,
MAX31827_CONFIGURATION_REG,
MAX31827_CONFIGURATION_1SHOT_MASK,
1);
if (ret) {
mutex_unlock(&st->lock);
return ret;
}
msleep(MAX31827_12_BIT_CNV_TIME);
}
ret = regmap_read(st->regmap, MAX31827_T_REG, &uval);
mutex_unlock(&st->lock);
if (ret)
break;
*val = MAX31827_16_BIT_TO_M_DGR(uval);
break;
case hwmon_temp_max:
ret = regmap_read(st->regmap, MAX31827_TH_REG, &uval);
if (ret)
break;
*val = MAX31827_16_BIT_TO_M_DGR(uval);
break;
case hwmon_temp_max_hyst:
ret = regmap_read(st->regmap, MAX31827_TH_HYST_REG,
&uval);
if (ret)
break;
*val = MAX31827_16_BIT_TO_M_DGR(uval);
break;
case hwmon_temp_max_alarm:
ret = regmap_read(st->regmap,
MAX31827_CONFIGURATION_REG, &uval);
if (ret)
break;
*val = FIELD_GET(MAX31827_CONFIGURATION_O_TEMP_STAT_MASK,
uval);
break;
case hwmon_temp_min:
ret = regmap_read(st->regmap, MAX31827_TL_REG, &uval);
if (ret)
break;
*val = MAX31827_16_BIT_TO_M_DGR(uval);
break;
case hwmon_temp_min_hyst:
ret = regmap_read(st->regmap, MAX31827_TL_HYST_REG,
&uval);
if (ret)
break;
*val = MAX31827_16_BIT_TO_M_DGR(uval);
break;
case hwmon_temp_min_alarm:
ret = regmap_read(st->regmap,
MAX31827_CONFIGURATION_REG, &uval);
if (ret)
break;
*val = FIELD_GET(MAX31827_CONFIGURATION_U_TEMP_STAT_MASK,
uval);
break;
default:
ret = -EOPNOTSUPP;
break;
}
break;
case hwmon_chip:
if (attr == hwmon_chip_update_interval) {
ret = regmap_read(st->regmap,
MAX31827_CONFIGURATION_REG, &uval);
if (ret)
break;
uval = FIELD_GET(MAX31827_CONFIGURATION_CNV_RATE_MASK,
uval);
switch (uval) {
case MAX31827_CNV_1_DIV_64_HZ:
*val = 64000;
break;
case MAX31827_CNV_1_DIV_32_HZ:
*val = 32000;
break;
case MAX31827_CNV_1_DIV_16_HZ:
*val = 16000;
break;
case MAX31827_CNV_1_DIV_4_HZ:
*val = 4000;
break;
case MAX31827_CNV_1_HZ:
*val = 1000;
break;
case MAX31827_CNV_4_HZ:
*val = 250;
break;
case MAX31827_CNV_8_HZ:
*val = 125;
break;
default:
*val = 0;
break;
}
}
break;
default:
ret = -EOPNOTSUPP;
break;
}
return ret;
}
static int max31827_write(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long val)
{
struct max31827_state *st = dev_get_drvdata(dev);
int ret;
switch (type) {
case hwmon_temp:
switch (attr) {
case hwmon_temp_enable:
if (val >> 1)
return -EINVAL;
mutex_lock(&st->lock);
/**
* The chip should not be enabled while a conversion is
* performed. Neither should the chip be enabled when
* the alarm values are changed.
*/
st->enable = val;
ret = regmap_update_bits(st->regmap,
MAX31827_CONFIGURATION_REG,
MAX31827_CONFIGURATION_1SHOT_MASK |
MAX31827_CONFIGURATION_CNV_RATE_MASK,
MAX31827_DEVICE_ENABLE(val));
mutex_unlock(&st->lock);
return ret;
case hwmon_temp_max:
return write_alarm_val(st, MAX31827_TH_REG, val);
case hwmon_temp_max_hyst:
return write_alarm_val(st, MAX31827_TH_HYST_REG, val);
case hwmon_temp_min:
return write_alarm_val(st, MAX31827_TL_REG, val);
case hwmon_temp_min_hyst:
return write_alarm_val(st, MAX31827_TL_HYST_REG, val);
default:
return -EOPNOTSUPP;
}
case hwmon_chip:
if (attr == hwmon_chip_update_interval) {
if (!st->enable)
return -EINVAL;
switch (val) {
case 125:
val = MAX31827_CNV_8_HZ;
break;
case 250:
val = MAX31827_CNV_4_HZ;
break;
case 1000:
val = MAX31827_CNV_1_HZ;
break;
case 4000:
val = MAX31827_CNV_1_DIV_4_HZ;
break;
case 16000:
val = MAX31827_CNV_1_DIV_16_HZ;
break;
case 32000:
val = MAX31827_CNV_1_DIV_32_HZ;
break;
case 64000:
val = MAX31827_CNV_1_DIV_64_HZ;
break;
default:
return -EINVAL;
}
val = FIELD_PREP(MAX31827_CONFIGURATION_CNV_RATE_MASK,
val);
return regmap_update_bits(st->regmap,
MAX31827_CONFIGURATION_REG,
MAX31827_CONFIGURATION_CNV_RATE_MASK,
val);
}
break;
default:
return -EOPNOTSUPP;
}
return -EOPNOTSUPP;
}
static int max31827_init_client(struct max31827_state *st)
{
st->enable = true;
return regmap_update_bits(st->regmap, MAX31827_CONFIGURATION_REG,
MAX31827_CONFIGURATION_1SHOT_MASK |
MAX31827_CONFIGURATION_CNV_RATE_MASK,
MAX31827_DEVICE_ENABLE(1));
}
static const struct hwmon_channel_info *max31827_info[] = {
HWMON_CHANNEL_INFO(temp, HWMON_T_ENABLE | HWMON_T_INPUT | HWMON_T_MIN |
HWMON_T_MIN_HYST | HWMON_T_MIN_ALARM |
HWMON_T_MAX | HWMON_T_MAX_HYST |
HWMON_T_MAX_ALARM),
HWMON_CHANNEL_INFO(chip, HWMON_C_UPDATE_INTERVAL),
NULL,
};
static const struct hwmon_ops max31827_hwmon_ops = {
.is_visible = max31827_is_visible,
.read = max31827_read,
.write = max31827_write,
};
static const struct hwmon_chip_info max31827_chip_info = {
.ops = &max31827_hwmon_ops,
.info = max31827_info,
};
static int max31827_probe(struct i2c_client *client)
{
struct device *dev = &client->dev;
struct device *hwmon_dev;
struct max31827_state *st;
int err;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
return -EOPNOTSUPP;
st = devm_kzalloc(dev, sizeof(*st), GFP_KERNEL);
if (!st)
return -ENOMEM;
mutex_init(&st->lock);
st->regmap = devm_regmap_init_i2c(client, &max31827_regmap);
if (IS_ERR(st->regmap))
return dev_err_probe(dev, PTR_ERR(st->regmap),
"Failed to allocate regmap.\n");
err = max31827_init_client(st);
if (err)
return err;
hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, st,
&max31827_chip_info,
NULL);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id max31827_i2c_ids[] = {
{ "max31827", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, max31827_i2c_ids);
static const struct of_device_id max31827_of_match[] = {
{ .compatible = "adi,max31827" },
{ }
};
MODULE_DEVICE_TABLE(of, max31827_of_match);
static struct i2c_driver max31827_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "max31827",
.of_match_table = max31827_of_match,
},
.probe_new = max31827_probe,
.id_table = max31827_i2c_ids,
};
module_i2c_driver(max31827_driver);
MODULE_AUTHOR("Daniel Matyas <daniel.matyas@analog.com>");
MODULE_DESCRIPTION("Maxim MAX31827 low-power temperature switch driver");
MODULE_LICENSE("GPL");
Reference in New Issue View Git Blame Copy Permalink