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linux-next/drivers/hwmon/tmp108.c
John Muir 66e1c91713 hwmon: Add Texas Instruments TMP108 temperature sensor driver. 
Add support for the TI TMP108 temperature sensor with some device
configuration parameters.

Signed-off-by: John Muir <john@jmuir.com>
[groeck: Initialize of_match_table]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2016-12-09 21:54:25 -08:00

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/* Texas Instruments TMP108 SMBus temperature sensor driver
*
* Copyright (C) 2016 John Muir <john@jmuir.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#define DRIVER_NAME "tmp108"
#define TMP108_REG_TEMP 0x00
#define TMP108_REG_CONF 0x01
#define TMP108_REG_TLOW 0x02
#define TMP108_REG_THIGH 0x03
#define TMP108_TEMP_MIN_MC -50000 /* Minimum millicelcius. */
#define TMP108_TEMP_MAX_MC 127937 /* Maximum millicelcius. */
/* Configuration register bits.
* Note: these bit definitions are byte swapped.
*/
#define TMP108_CONF_M0 0x0100 /* Sensor mode. */
#define TMP108_CONF_M1 0x0200
#define TMP108_CONF_TM 0x0400 /* Thermostat mode. */
#define TMP108_CONF_FL 0x0800 /* Watchdog flag - TLOW */
#define TMP108_CONF_FH 0x1000 /* Watchdog flag - THIGH */
#define TMP108_CONF_CR0 0x2000 /* Conversion rate. */
#define TMP108_CONF_CR1 0x4000
#define TMP108_CONF_ID 0x8000
#define TMP108_CONF_HYS0 0x0010 /* Hysteresis. */
#define TMP108_CONF_HYS1 0x0020
#define TMP108_CONF_POL 0x0080 /* Polarity of alert. */
/* Defaults set by the hardware upon reset. */
#define TMP108_CONF_DEFAULTS (TMP108_CONF_CR0 | TMP108_CONF_TM |\
TMP108_CONF_HYS0 | TMP108_CONF_M1)
/* These bits are read-only. */
#define TMP108_CONF_READ_ONLY (TMP108_CONF_FL | TMP108_CONF_FH |\
TMP108_CONF_ID)
#define TMP108_CONF_MODE_MASK (TMP108_CONF_M0|TMP108_CONF_M1)
#define TMP108_MODE_SHUTDOWN 0x0000
#define TMP108_MODE_ONE_SHOT TMP108_CONF_M0
#define TMP108_MODE_CONTINUOUS TMP108_CONF_M1 /* Default */
/* When M1 is set, M0 is ignored. */
#define TMP108_CONF_CONVRATE_MASK (TMP108_CONF_CR0|TMP108_CONF_CR1)
#define TMP108_CONVRATE_0P25HZ 0x0000
#define TMP108_CONVRATE_1HZ TMP108_CONF_CR0 /* Default */
#define TMP108_CONVRATE_4HZ TMP108_CONF_CR1
#define TMP108_CONVRATE_16HZ (TMP108_CONF_CR0|TMP108_CONF_CR1)
#define TMP108_CONF_HYSTERESIS_MASK (TMP108_CONF_HYS0|TMP108_CONF_HYS1)
#define TMP108_HYSTERESIS_0C 0x0000
#define TMP108_HYSTERESIS_1C TMP108_CONF_HYS0 /* Default */
#define TMP108_HYSTERESIS_2C TMP108_CONF_HYS1
#define TMP108_HYSTERESIS_4C (TMP108_CONF_HYS0|TMP108_CONF_HYS1)
#define TMP108_CONVERSION_TIME_MS 30 /* in milli-seconds */
struct tmp108 {
struct regmap *regmap;
u16 orig_config;
unsigned long ready_time;
};
/* convert 12-bit TMP108 register value to milliCelsius */
static inline int tmp108_temp_reg_to_mC(s16 val)
{
return (val & ~0x0f) * 1000 / 256;
}
/* convert milliCelsius to left adjusted 12-bit TMP108 register value */
static inline u16 tmp108_mC_to_temp_reg(int val)
{
return (val * 256) / 1000;
}
static int tmp108_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *temp)
{
struct tmp108 *tmp108 = dev_get_drvdata(dev);
unsigned int regval;
int err, hyst;
if (type == hwmon_chip) {
if (attr == hwmon_chip_update_interval) {
err = regmap_read(tmp108->regmap, TMP108_REG_CONF,
&regval);
if (err < 0)
return err;
switch (regval & TMP108_CONF_CONVRATE_MASK) {
case TMP108_CONVRATE_0P25HZ:
default:
*temp = 4000;
break;
case TMP108_CONVRATE_1HZ:
*temp = 1000;
break;
case TMP108_CONVRATE_4HZ:
*temp = 250;
break;
case TMP108_CONVRATE_16HZ:
*temp = 63;
break;
}
return 0;
}
return -EOPNOTSUPP;
}
switch (attr) {
case hwmon_temp_input:
/* Is it too early to return a conversion ? */
if (time_before(jiffies, tmp108->ready_time)) {
dev_dbg(dev, "%s: Conversion not ready yet..\n",
__func__);
return -EAGAIN;
}
err = regmap_read(tmp108->regmap, TMP108_REG_TEMP, &regval);
if (err < 0)
return err;
*temp = tmp108_temp_reg_to_mC(regval);
break;
case hwmon_temp_min:
case hwmon_temp_max:
err = regmap_read(tmp108->regmap, attr == hwmon_temp_min ?
TMP108_REG_TLOW : TMP108_REG_THIGH, &regval);
if (err < 0)
return err;
*temp = tmp108_temp_reg_to_mC(regval);
break;
case hwmon_temp_min_alarm:
case hwmon_temp_max_alarm:
err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &regval);
if (err < 0)
return err;
*temp = !!(regval & (attr == hwmon_temp_min_alarm ?
TMP108_CONF_FL : TMP108_CONF_FH));
break;
case hwmon_temp_min_hyst:
case hwmon_temp_max_hyst:
err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &regval);
if (err < 0)
return err;
switch (regval & TMP108_CONF_HYSTERESIS_MASK) {
case TMP108_HYSTERESIS_0C:
default:
hyst = 0;
break;
case TMP108_HYSTERESIS_1C:
hyst = 1000;
break;
case TMP108_HYSTERESIS_2C:
hyst = 2000;
break;
case TMP108_HYSTERESIS_4C:
hyst = 4000;
break;
}
err = regmap_read(tmp108->regmap, attr == hwmon_temp_min_hyst ?
TMP108_REG_TLOW : TMP108_REG_THIGH, &regval);
if (err < 0)
return err;
*temp = tmp108_temp_reg_to_mC(regval);
if (attr == hwmon_temp_min_hyst)
*temp += hyst;
else
*temp -= hyst;
break;
default:
return -EOPNOTSUPP;
}
return 0;
}
static int tmp108_write(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long temp)
{
struct tmp108 *tmp108 = dev_get_drvdata(dev);
u32 regval, mask;
int err;
if (type == hwmon_chip) {
if (attr == hwmon_chip_update_interval) {
if (temp < 156)
mask = TMP108_CONVRATE_16HZ;
else if (temp < 625)
mask = TMP108_CONVRATE_4HZ;
else if (temp < 2500)
mask = TMP108_CONVRATE_1HZ;
else
mask = TMP108_CONVRATE_0P25HZ;
return regmap_update_bits(tmp108->regmap,
TMP108_REG_CONF,
TMP108_CONF_CONVRATE_MASK,
mask);
}
return -EOPNOTSUPP;
}
switch (attr) {
case hwmon_temp_min:
case hwmon_temp_max:
temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
return regmap_write(tmp108->regmap,
attr == hwmon_temp_min ?
TMP108_REG_TLOW : TMP108_REG_THIGH,
tmp108_mC_to_temp_reg(temp));
case hwmon_temp_min_hyst:
case hwmon_temp_max_hyst:
temp = clamp_val(temp, TMP108_TEMP_MIN_MC, TMP108_TEMP_MAX_MC);
err = regmap_read(tmp108->regmap,
attr == hwmon_temp_min_hyst ?
TMP108_REG_TLOW : TMP108_REG_THIGH,
&regval);
if (err < 0)
return err;
if (attr == hwmon_temp_min_hyst)
temp -= tmp108_temp_reg_to_mC(regval);
else
temp = tmp108_temp_reg_to_mC(regval) - temp;
if (temp < 500)
mask = TMP108_HYSTERESIS_0C;
else if (temp < 1500)
mask = TMP108_HYSTERESIS_1C;
else if (temp < 3000)
mask = TMP108_HYSTERESIS_2C;
else
mask = TMP108_HYSTERESIS_4C;
return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
TMP108_CONF_HYSTERESIS_MASK, mask);
default:
return -EOPNOTSUPP;
}
}
static umode_t tmp108_is_visible(const void *data, enum hwmon_sensor_types type,
u32 attr, int channel)
{
if (type == hwmon_chip && attr == hwmon_chip_update_interval)
return 0644;
if (type != hwmon_temp)
return 0;
switch (attr) {
case hwmon_temp_input:
case hwmon_temp_min_alarm:
case hwmon_temp_max_alarm:
return 0444;
case hwmon_temp_min:
case hwmon_temp_max:
case hwmon_temp_min_hyst:
case hwmon_temp_max_hyst:
return 0644;
default:
return 0;
}
}
static u32 tmp108_chip_config[] = {
HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL,
0
};
static const struct hwmon_channel_info tmp108_chip = {
.type = hwmon_chip,
.config = tmp108_chip_config,
};
static u32 tmp108_temp_config[] = {
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN | HWMON_T_MIN_HYST
| HWMON_T_MAX_HYST | HWMON_T_MIN_ALARM | HWMON_T_MAX_ALARM,
0
};
static const struct hwmon_channel_info tmp108_temp = {
.type = hwmon_temp,
.config = tmp108_temp_config,
};
static const struct hwmon_channel_info *tmp108_info[] = {
&tmp108_chip,
&tmp108_temp,
NULL
};
static const struct hwmon_ops tmp108_hwmon_ops = {
.is_visible = tmp108_is_visible,
.read = tmp108_read,
.write = tmp108_write,
};
static const struct hwmon_chip_info tmp108_chip_info = {
.ops = &tmp108_hwmon_ops,
.info = tmp108_info,
};
static void tmp108_restore_config(void *data)
{
struct tmp108 *tmp108 = data;
regmap_write(tmp108->regmap, TMP108_REG_CONF, tmp108->orig_config);
}
static bool tmp108_is_writeable_reg(struct device *dev, unsigned int reg)
{
return reg != TMP108_REG_TEMP;
}
static bool tmp108_is_volatile_reg(struct device *dev, unsigned int reg)
{
/* Configuration register must be volatile to enable FL and FH. */
return reg == TMP108_REG_TEMP || reg == TMP108_REG_CONF;
}
static const struct regmap_config tmp108_regmap_config = {
.reg_bits = 8,
.val_bits = 16,
.max_register = TMP108_REG_THIGH,
.writeable_reg = tmp108_is_writeable_reg,
.volatile_reg = tmp108_is_volatile_reg,
.val_format_endian = REGMAP_ENDIAN_BIG,
.cache_type = REGCACHE_RBTREE,
.use_single_rw = true,
};
static int tmp108_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct device *hwmon_dev;
struct tmp108 *tmp108;
int err;
u32 config;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_WORD_DATA)) {
dev_err(dev,
"adapter doesn't support SMBus word transactions\n");
return -ENODEV;
}
tmp108 = devm_kzalloc(dev, sizeof(*tmp108), GFP_KERNEL);
if (!tmp108)
return -ENOMEM;
dev_set_drvdata(dev, tmp108);
tmp108->regmap = devm_regmap_init_i2c(client, &tmp108_regmap_config);
if (IS_ERR(tmp108->regmap)) {
err = PTR_ERR(tmp108->regmap);
dev_err(dev, "regmap init failed: %d", err);
return err;
}
err = regmap_read(tmp108->regmap, TMP108_REG_CONF, &config);
if (err < 0) {
dev_err(dev, "error reading config register: %d", err);
return err;
}
tmp108->orig_config = config;
/* Only continuous mode is supported. */
config &= ~TMP108_CONF_MODE_MASK;
config |= TMP108_MODE_CONTINUOUS;
/* Only comparator mode is supported. */
config &= ~TMP108_CONF_TM;
err = regmap_write(tmp108->regmap, TMP108_REG_CONF, config);
if (err < 0) {
dev_err(dev, "error writing config register: %d", err);
return err;
}
tmp108->ready_time = jiffies;
if ((tmp108->orig_config & TMP108_CONF_MODE_MASK) ==
TMP108_MODE_SHUTDOWN)
tmp108->ready_time +=
msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
err = devm_add_action_or_reset(dev, tmp108_restore_config, tmp108);
if (err) {
dev_err(dev, "add action or reset failed: %d", err);
return err;
}
hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
tmp108,
&tmp108_chip_info,
NULL);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static int __maybe_unused tmp108_suspend(struct device *dev)
{
struct tmp108 *tmp108 = dev_get_drvdata(dev);
return regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
TMP108_CONF_MODE_MASK, TMP108_MODE_SHUTDOWN);
}
static int __maybe_unused tmp108_resume(struct device *dev)
{
struct tmp108 *tmp108 = dev_get_drvdata(dev);
int err;
err = regmap_update_bits(tmp108->regmap, TMP108_REG_CONF,
TMP108_CONF_MODE_MASK, TMP108_MODE_CONTINUOUS);
tmp108->ready_time = jiffies +
msecs_to_jiffies(TMP108_CONVERSION_TIME_MS);
return err;
}
static SIMPLE_DEV_PM_OPS(tmp108_dev_pm_ops, tmp108_suspend, tmp108_resume);
static const struct i2c_device_id tmp108_i2c_ids[] = {
{ "tmp108", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, tmp108_i2c_ids);
#ifdef CONFIG_OF
static const struct of_device_id tmp108_of_ids[] = {
{ .compatible = "ti,tmp108", },
{}
};
MODULE_DEVICE_TABLE(of, tmp108_of_ids);
#endif
static struct i2c_driver tmp108_driver = {
.driver = {
.name = DRIVER_NAME,
.pm = &tmp108_dev_pm_ops,
.of_match_table = of_match_ptr(tmp108_of_ids),
},
.probe = tmp108_probe,
.id_table = tmp108_i2c_ids,
};
module_i2c_driver(tmp108_driver);
MODULE_AUTHOR("John Muir <john@jmuir.com>");
MODULE_DESCRIPTION("Texas Instruments TMP108 temperature sensor driver");
MODULE_LICENSE("GPL");
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