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linux/drivers/hwmon/lm75.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* lm75.c - Part of lm_sensors, Linux kernel modules for hardware
* monitoring
* Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/of_device.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include "lm75.h"
/*
* This driver handles the LM75 and compatible digital temperature sensors.
*/
enum lm75_type { /* keep sorted in alphabetical order */
adt75,
ds1775,
ds75,
ds7505,
g751,
lm75,
lm75a,
lm75b,
max6625,
max6626,
max31725,
mcp980x,
stds75,
stlm75,
tcn75,
tmp100,
tmp101,
tmp105,
tmp112,
tmp175,
tmp275,
tmp75,
tmp75b,
tmp75c,
};
/* Addresses scanned */
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
/* The LM75 registers */
#define LM75_REG_TEMP 0x00
#define LM75_REG_CONF 0x01
#define LM75_REG_HYST 0x02
#define LM75_REG_MAX 0x03
/* Each client has this additional data */
struct lm75_data {
struct i2c_client *client;
struct regmap *regmap;
u8 orig_conf;
u8 resolution; /* In bits, between 9 and 16 */
u8 resolution_limits;
unsigned int sample_time; /* In ms */
};
/*-----------------------------------------------------------------------*/
static inline long lm75_reg_to_mc(s16 temp, u8 resolution)
{
return ((temp >> (16 - resolution)) * 1000) >> (resolution - 8);
}
static int lm75_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
struct lm75_data *data = dev_get_drvdata(dev);
unsigned int regval;
int err, reg;
switch (type) {
case hwmon_chip:
switch (attr) {
case hwmon_chip_update_interval:
*val = data->sample_time;
break;
default:
return -EINVAL;
}
break;
case hwmon_temp:
switch (attr) {
case hwmon_temp_input:
reg = LM75_REG_TEMP;
break;
case hwmon_temp_max:
reg = LM75_REG_MAX;
break;
case hwmon_temp_max_hyst:
reg = LM75_REG_HYST;
break;
default:
return -EINVAL;
}
err = regmap_read(data->regmap, reg, &regval);
if (err < 0)
return err;
*val = lm75_reg_to_mc(regval, data->resolution);
break;
default:
return -EINVAL;
}
return 0;
}
static int lm75_write(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long temp)
{
struct lm75_data *data = dev_get_drvdata(dev);
u8 resolution;
int reg;
if (type != hwmon_temp)
return -EINVAL;
switch (attr) {
case hwmon_temp_max:
reg = LM75_REG_MAX;
break;
case hwmon_temp_max_hyst:
reg = LM75_REG_HYST;
break;
default:
return -EINVAL;
}
/*
* Resolution of limit registers is assumed to be the same as the
* temperature input register resolution unless given explicitly.
*/
if (data->resolution_limits)
resolution = data->resolution_limits;
else
resolution = data->resolution;
temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
temp = DIV_ROUND_CLOSEST(temp << (resolution - 8),
1000) << (16 - resolution);
return regmap_write(data->regmap, reg, temp);
}
static umode_t lm75_is_visible(const void *data, enum hwmon_sensor_types type,
u32 attr, int channel)
{
switch (type) {
case hwmon_chip:
switch (attr) {
case hwmon_chip_update_interval:
return 0444;
}
break;
case hwmon_temp:
switch (attr) {
case hwmon_temp_input:
return 0444;
case hwmon_temp_max:
case hwmon_temp_max_hyst:
return 0644;
}
break;
default:
break;
}
return 0;
}
static const struct hwmon_channel_info *lm75_info[] = {
HWMON_CHANNEL_INFO(chip,
HWMON_C_REGISTER_TZ | HWMON_C_UPDATE_INTERVAL),
HWMON_CHANNEL_INFO(temp,
HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MAX_HYST),
NULL
};
static const struct hwmon_ops lm75_hwmon_ops = {
.is_visible = lm75_is_visible,
.read = lm75_read,
.write = lm75_write,
};
static const struct hwmon_chip_info lm75_chip_info = {
.ops = &lm75_hwmon_ops,
.info = lm75_info,
};
static bool lm75_is_writeable_reg(struct device *dev, unsigned int reg)
{
return reg != LM75_REG_TEMP;
}
static bool lm75_is_volatile_reg(struct device *dev, unsigned int reg)
{
return reg == LM75_REG_TEMP;
}
static const struct regmap_config lm75_regmap_config = {
.reg_bits = 8,
.val_bits = 16,
.max_register = LM75_REG_MAX,
.writeable_reg = lm75_is_writeable_reg,
.volatile_reg = lm75_is_volatile_reg,
.val_format_endian = REGMAP_ENDIAN_BIG,
.cache_type = REGCACHE_RBTREE,
.use_single_read = true,
.use_single_write = true,
};
static void lm75_remove(void *data)
{
struct lm75_data *lm75 = data;
struct i2c_client *client = lm75->client;
i2c_smbus_write_byte_data(client, LM75_REG_CONF, lm75->orig_conf);
}
static int
lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct device *hwmon_dev;
struct lm75_data *data;
int status, err;
u8 set_mask, clr_mask;
int new;
enum lm75_type kind;
if (client->dev.of_node)
kind = (enum lm75_type)of_device_get_match_data(&client->dev);
else
kind = id->driver_data;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
return -EIO;
data = devm_kzalloc(dev, sizeof(struct lm75_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = client;
data->regmap = devm_regmap_init_i2c(client, &lm75_regmap_config);
if (IS_ERR(data->regmap))
return PTR_ERR(data->regmap);
/* Set to LM75 resolution (9 bits, 1/2 degree C) and range.
* Then tweak to be more precise when appropriate.
*/
set_mask = 0;
clr_mask = LM75_SHUTDOWN; /* continuous conversions */
switch (kind) {
case adt75:
clr_mask |= 1 << 5; /* not one-shot mode */
data->resolution = 12;
data->sample_time = MSEC_PER_SEC / 8;
break;
case ds1775:
case ds75:
case stds75:
clr_mask |= 3 << 5;
set_mask |= 2 << 5; /* 11-bit mode */
data->resolution = 11;
data->sample_time = MSEC_PER_SEC;
break;
case stlm75:
data->resolution = 9;
data->sample_time = MSEC_PER_SEC / 5;
break;
case ds7505:
set_mask |= 3 << 5; /* 12-bit mode */
data->resolution = 12;
data->sample_time = MSEC_PER_SEC / 4;
break;
case g751:
case lm75:
case lm75a:
data->resolution = 9;
data->sample_time = MSEC_PER_SEC / 2;
break;
case lm75b:
data->resolution = 11;
data->sample_time = MSEC_PER_SEC / 4;
break;
case max6625:
data->resolution = 9;
data->sample_time = MSEC_PER_SEC / 4;
break;
case max6626:
data->resolution = 12;
data->resolution_limits = 9;
data->sample_time = MSEC_PER_SEC / 4;
break;
case max31725:
data->resolution = 16;
data->sample_time = MSEC_PER_SEC / 8;
break;
case tcn75:
data->resolution = 9;
data->sample_time = MSEC_PER_SEC / 8;
break;
case mcp980x:
data->resolution_limits = 9;
/* fall through */
case tmp100:
case tmp101:
set_mask |= 3 << 5; /* 12-bit mode */
data->resolution = 12;
data->sample_time = MSEC_PER_SEC;
clr_mask |= 1 << 7; /* not one-shot mode */
break;
case tmp112:
set_mask |= 3 << 5; /* 12-bit mode */
clr_mask |= 1 << 7; /* not one-shot mode */
data->resolution = 12;
data->sample_time = MSEC_PER_SEC / 4;
break;
case tmp105:
case tmp175:
case tmp275:
case tmp75:
set_mask |= 3 << 5; /* 12-bit mode */
clr_mask |= 1 << 7; /* not one-shot mode */
data->resolution = 12;
data->sample_time = MSEC_PER_SEC / 2;
break;
case tmp75b: /* not one-shot mode, Conversion rate 37Hz */
clr_mask |= 1 << 7 | 0x3 << 5;
data->resolution = 12;
data->sample_time = MSEC_PER_SEC / 37;
break;
case tmp75c:
clr_mask |= 1 << 5; /* not one-shot mode */
data->resolution = 12;
data->sample_time = MSEC_PER_SEC / 4;
break;
}
/* configure as specified */
status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
if (status < 0) {
dev_dbg(dev, "Can't read config? %d\n", status);
return status;
}
data->orig_conf = status;
new = status & ~clr_mask;
new |= set_mask;
if (status != new)
i2c_smbus_write_byte_data(client, LM75_REG_CONF, new);
err = devm_add_action_or_reset(dev, lm75_remove, data);
if (err)
return err;
dev_dbg(dev, "Config %02x\n", new);
hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
data, &lm75_chip_info,
NULL);
if (IS_ERR(hwmon_dev))
return PTR_ERR(hwmon_dev);
dev_info(dev, "%s: sensor '%s'\n", dev_name(hwmon_dev), client->name);
return 0;
}
static const struct i2c_device_id lm75_ids[] = {
{ "adt75", adt75, },
{ "ds1775", ds1775, },
{ "ds75", ds75, },
{ "ds7505", ds7505, },
{ "g751", g751, },
{ "lm75", lm75, },
{ "lm75a", lm75a, },
{ "lm75b", lm75b, },
{ "max6625", max6625, },
{ "max6626", max6626, },
{ "max31725", max31725, },
{ "max31726", max31725, },
{ "mcp980x", mcp980x, },
{ "stds75", stds75, },
{ "stlm75", stlm75, },
{ "tcn75", tcn75, },
{ "tmp100", tmp100, },
{ "tmp101", tmp101, },
{ "tmp105", tmp105, },
{ "tmp112", tmp112, },
{ "tmp175", tmp175, },
{ "tmp275", tmp275, },
{ "tmp75", tmp75, },
{ "tmp75b", tmp75b, },
{ "tmp75c", tmp75c, },
{ /* LIST END */ }
};
MODULE_DEVICE_TABLE(i2c, lm75_ids);
static const struct of_device_id __maybe_unused lm75_of_match[] = {
{
.compatible = "adi,adt75",
.data = (void *)adt75
},
{
.compatible = "dallas,ds1775",
.data = (void *)ds1775
},
{
.compatible = "dallas,ds75",
.data = (void *)ds75
},
{
.compatible = "dallas,ds7505",
.data = (void *)ds7505
},
{
.compatible = "gmt,g751",
.data = (void *)g751
},
{
.compatible = "national,lm75",
.data = (void *)lm75
},
{
.compatible = "national,lm75a",
.data = (void *)lm75a
},
{
.compatible = "national,lm75b",
.data = (void *)lm75b
},
{
.compatible = "maxim,max6625",
.data = (void *)max6625
},
{
.compatible = "maxim,max6626",
.data = (void *)max6626
},
{
.compatible = "maxim,max31725",
.data = (void *)max31725
},
{
.compatible = "maxim,max31726",
.data = (void *)max31725
},
{
.compatible = "maxim,mcp980x",
.data = (void *)mcp980x
},
{
.compatible = "st,stds75",
.data = (void *)stds75
},
{
.compatible = "st,stlm75",
.data = (void *)stlm75
},
{
.compatible = "microchip,tcn75",
.data = (void *)tcn75
},
{
.compatible = "ti,tmp100",
.data = (void *)tmp100
},
{
.compatible = "ti,tmp101",
.data = (void *)tmp101
},
{
.compatible = "ti,tmp105",
.data = (void *)tmp105
},
{
.compatible = "ti,tmp112",
.data = (void *)tmp112
},
{
.compatible = "ti,tmp175",
.data = (void *)tmp175
},
{
.compatible = "ti,tmp275",
.data = (void *)tmp275
},
{
.compatible = "ti,tmp75",
.data = (void *)tmp75
},
{
.compatible = "ti,tmp75b",
.data = (void *)tmp75b
},
{
.compatible = "ti,tmp75c",
.data = (void *)tmp75c
},
{ },
};
MODULE_DEVICE_TABLE(of, lm75_of_match);
#define LM75A_ID 0xA1
/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm75_detect(struct i2c_client *new_client,
struct i2c_board_info *info)
{
struct i2c_adapter *adapter = new_client->adapter;
int i;
int conf, hyst, os;
bool is_lm75a = 0;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
/*
* Now, we do the remaining detection. There is no identification-
* dedicated register so we have to rely on several tricks:
* unused bits, registers cycling over 8-address boundaries,
* addresses 0x04-0x07 returning the last read value.
* The cycling+unused addresses combination is not tested,
* since it would significantly slow the detection down and would
* hardly add any value.
*
* The National Semiconductor LM75A is different than earlier
* LM75s. It has an ID byte of 0xaX (where X is the chip
* revision, with 1 being the only revision in existence) in
* register 7, and unused registers return 0xff rather than the
* last read value.
*
* Note that this function only detects the original National
* Semiconductor LM75 and the LM75A. Clones from other vendors
* aren't detected, on purpose, because they are typically never
* found on PC hardware. They are found on embedded designs where
* they can be instantiated explicitly so detection is not needed.
* The absence of identification registers on all these clones
* would make their exhaustive detection very difficult and weak,
* and odds are that the driver would bind to unsupported devices.
*/
/* Unused bits */
conf = i2c_smbus_read_byte_data(new_client, 1);
if (conf & 0xe0)
return -ENODEV;
/* First check for LM75A */
if (i2c_smbus_read_byte_data(new_client, 7) == LM75A_ID) {
/* LM75A returns 0xff on unused registers so
just to be sure we check for that too. */
if (i2c_smbus_read_byte_data(new_client, 4) != 0xff
|| i2c_smbus_read_byte_data(new_client, 5) != 0xff
|| i2c_smbus_read_byte_data(new_client, 6) != 0xff)
return -ENODEV;
is_lm75a = 1;
hyst = i2c_smbus_read_byte_data(new_client, 2);
os = i2c_smbus_read_byte_data(new_client, 3);
} else { /* Traditional style LM75 detection */
/* Unused addresses */
hyst = i2c_smbus_read_byte_data(new_client, 2);
if (i2c_smbus_read_byte_data(new_client, 4) != hyst
|| i2c_smbus_read_byte_data(new_client, 5) != hyst
|| i2c_smbus_read_byte_data(new_client, 6) != hyst
|| i2c_smbus_read_byte_data(new_client, 7) != hyst)
return -ENODEV;
os = i2c_smbus_read_byte_data(new_client, 3);
if (i2c_smbus_read_byte_data(new_client, 4) != os
|| i2c_smbus_read_byte_data(new_client, 5) != os
|| i2c_smbus_read_byte_data(new_client, 6) != os
|| i2c_smbus_read_byte_data(new_client, 7) != os)
return -ENODEV;
}
/*
* It is very unlikely that this is a LM75 if both
* hysteresis and temperature limit registers are 0.
*/
if (hyst == 0 && os == 0)
return -ENODEV;
/* Addresses cycling */
for (i = 8; i <= 248; i += 40) {
if (i2c_smbus_read_byte_data(new_client, i + 1) != conf
|| i2c_smbus_read_byte_data(new_client, i + 2) != hyst
|| i2c_smbus_read_byte_data(new_client, i + 3) != os)
return -ENODEV;
if (is_lm75a && i2c_smbus_read_byte_data(new_client, i + 7)
!= LM75A_ID)
return -ENODEV;
}
strlcpy(info->type, is_lm75a ? "lm75a" : "lm75", I2C_NAME_SIZE);
return 0;
}
#ifdef CONFIG_PM
static int lm75_suspend(struct device *dev)
{
int status;
struct i2c_client *client = to_i2c_client(dev);
status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
if (status < 0) {
dev_dbg(&client->dev, "Can't read config? %d\n", status);
return status;
}
status = status | LM75_SHUTDOWN;
i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
return 0;
}
static int lm75_resume(struct device *dev)
{
int status;
struct i2c_client *client = to_i2c_client(dev);
status = i2c_smbus_read_byte_data(client, LM75_REG_CONF);
if (status < 0) {
dev_dbg(&client->dev, "Can't read config? %d\n", status);
return status;
}
status = status & ~LM75_SHUTDOWN;
i2c_smbus_write_byte_data(client, LM75_REG_CONF, status);
return 0;
}
static const struct dev_pm_ops lm75_dev_pm_ops = {
.suspend = lm75_suspend,
.resume = lm75_resume,
};
#define LM75_DEV_PM_OPS (&lm75_dev_pm_ops)
#else
#define LM75_DEV_PM_OPS NULL
#endif /* CONFIG_PM */
static struct i2c_driver lm75_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "lm75",
.of_match_table = of_match_ptr(lm75_of_match),
.pm = LM75_DEV_PM_OPS,
},
.probe = lm75_probe,
.id_table = lm75_ids,
.detect = lm75_detect,
.address_list = normal_i2c,
};
module_i2c_driver(lm75_driver);
MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
MODULE_DESCRIPTION("LM75 driver");
MODULE_LICENSE("GPL");
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