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/*
* lm75.c - Part of lm_sensors, Linux kernel modules for hardware
* monitoring
* Copyright (c) 1998, 1999 Frodo Looijaard <frodol@dds.nl>
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#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.h>
#include <linux/regmap.h>
#include <linux/thermal.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,
mcp980x,
stds75,
tcn75,
tmp100,
tmp101,
tmp105,
tmp112,
tmp175,
tmp275,
tmp75,
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 12 */
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);
}
/* sysfs attributes for hwmon */
static int lm75_read_temp(void *dev, int *temp)
{
struct lm75_data *data = dev_get_drvdata(dev);
unsigned int _temp;
int err;
err = regmap_read(data->regmap, LM75_REG_TEMP, &_temp);
if (err < 0)
return err;
*temp = lm75_reg_to_mc(_temp, data->resolution);
return 0;
}
static ssize_t show_temp(struct device *dev, struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct lm75_data *data = dev_get_drvdata(dev);
unsigned int temp = 0;
int err;
err = regmap_read(data->regmap, attr->index, &temp);
if (err < 0)
return err;
return sprintf(buf, "%ld\n", lm75_reg_to_mc(temp, data->resolution));
}
static ssize_t set_temp(struct device *dev, struct device_attribute *da,
const char *buf, size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct lm75_data *data = dev_get_drvdata(dev);
long temp;
int error;
u8 resolution;
error = kstrtol(buf, 10, &temp);
if (error)
return error;
/*
* Resolution of limit registers is assumed to be the same as the
* temperature input register resolution unless given explicitly.
*/
if (attr->index && 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);
error = regmap_write(data->regmap, attr->index, temp);
if (error < 0)
return error;
return count;
}
static ssize_t show_update_interval(struct device *dev,
struct device_attribute *da, char *buf)
{
struct lm75_data *data = dev_get_drvdata(dev);
return sprintf(buf, "%u\n", data->sample_time);
}
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
show_temp, set_temp, LM75_REG_MAX);
static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
show_temp, set_temp, LM75_REG_HYST);
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, LM75_REG_TEMP);
static DEVICE_ATTR(update_interval, S_IRUGO, show_update_interval, NULL);
static struct attribute *lm75_attrs[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp1_max.dev_attr.attr,
&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
&dev_attr_update_interval.attr,
NULL
};
ATTRIBUTE_GROUPS(lm75);
static const struct thermal_zone_of_device_ops lm75_of_thermal_ops = {
.get_temp = lm75_read_temp,
};
/*-----------------------------------------------------------------------*/
/* device probe and removal */
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_rw = 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;
u8 set_mask, clr_mask;
int new;
enum lm75_type 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 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 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 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);
devm_add_action(dev, lm75_remove, data);
dev_dbg(dev, "Config %02x\n", new);
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
data, lm75_groups);
if (IS_ERR(hwmon_dev))
return PTR_ERR(hwmon_dev);
devm_thermal_zone_of_sensor_register(hwmon_dev, 0,
hwmon_dev,
&lm75_of_thermal_ops);
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, },
{ "mcp980x", mcp980x, },
{ "stds75", stds75, },
{ "tcn75", tcn75, },
{ "tmp100", tmp100, },
{ "tmp101", tmp101, },
{ "tmp105", tmp105, },
{ "tmp112", tmp112, },
{ "tmp175", tmp175, },
{ "tmp275", tmp275, },
{ "tmp75", tmp75, },
{ "tmp75c", tmp75c, },
{ /* LIST END */ }
};
MODULE_DEVICE_TABLE(i2c, lm75_ids);
#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",
.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");