linux/drivers/hwmon/lm75.c
Eduardo Valentin 22e731838b hwmon: lm75: expose to thermal fw via DT nodes
This patch adds to lm75 temperature sensor the possibility
to expose itself as thermal zone device, registered on the
thermal framework.

The thermal zone is built only if a device tree node
describing a thermal zone for this sensor is present
inside the lm75 DT node. Otherwise, the driver behavior
will be the same.

Note: This patch has also been reviewed by Jean D. He has
requested to perform a wider inspection of possible
users of thermal and hwmon interaction API. On the other
hand, the change on this patch is acceptable on first
step of overall code change.

Cc: Jean Delvare <khali@linux-fr.org>
Cc: lm-sensors@lm-sensors.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
2013-12-04 09:34:24 -04:00

549 lines
14 KiB
C

/*
* 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/mutex.h>
#include <linux/of.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,
max6625,
max6626,
mcp980x,
stds75,
tcn75,
tmp100,
tmp101,
tmp105,
tmp175,
tmp275,
tmp75,
};
/* 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_CONF 0x01
static const u8 LM75_REG_TEMP[3] = {
0x00, /* input */
0x03, /* max */
0x02, /* hyst */
};
/* Each client has this additional data */
struct lm75_data {
struct device *hwmon_dev;
struct thermal_zone_device *tz;
struct mutex update_lock;
u8 orig_conf;
u8 resolution; /* In bits, between 9 and 12 */
u8 resolution_limits;
char valid; /* !=0 if registers are valid */
unsigned long last_updated; /* In jiffies */
unsigned long sample_time; /* In jiffies */
s16 temp[3]; /* Register values,
0 = input
1 = max
2 = hyst */
};
static int lm75_read_value(struct i2c_client *client, u8 reg);
static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value);
static struct lm75_data *lm75_update_device(struct device *dev);
/*-----------------------------------------------------------------------*/
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, long *temp)
{
struct lm75_data *data = lm75_update_device(dev);
if (IS_ERR(data))
return PTR_ERR(data);
*temp = lm75_reg_to_mc(data->temp[0], 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 = lm75_update_device(dev);
if (IS_ERR(data))
return PTR_ERR(data);
return sprintf(buf, "%ld\n", lm75_reg_to_mc(data->temp[attr->index],
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 i2c_client *client = to_i2c_client(dev);
struct lm75_data *data = i2c_get_clientdata(client);
int nr = attr->index;
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;
mutex_lock(&data->update_lock);
temp = clamp_val(temp, LM75_TEMP_MIN, LM75_TEMP_MAX);
data->temp[nr] = DIV_ROUND_CLOSEST(temp << (resolution - 8),
1000) << (16 - resolution);
lm75_write_value(client, LM75_REG_TEMP[nr], data->temp[nr]);
mutex_unlock(&data->update_lock);
return count;
}
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
show_temp, set_temp, 1);
static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
show_temp, set_temp, 2);
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static struct attribute *lm75_attributes[] = {
&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,
NULL
};
static const struct attribute_group lm75_group = {
.attrs = lm75_attributes,
};
/*-----------------------------------------------------------------------*/
/* device probe and removal */
static int
lm75_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
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(&client->dev, sizeof(struct lm75_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
/* 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 = HZ / 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 = HZ;
break;
case ds7505:
set_mask |= 3 << 5; /* 12-bit mode */
data->resolution = 12;
data->sample_time = HZ / 4;
break;
case g751:
case lm75:
case lm75a:
data->resolution = 9;
data->sample_time = HZ / 2;
break;
case max6625:
data->resolution = 9;
data->sample_time = HZ / 4;
break;
case max6626:
data->resolution = 12;
data->resolution_limits = 9;
data->sample_time = HZ / 4;
break;
case tcn75:
data->resolution = 9;
data->sample_time = HZ / 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 = HZ;
clr_mask |= 1 << 7; /* not one-shot mode */
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 = HZ / 2;
break;
}
/* configure as specified */
status = lm75_read_value(client, LM75_REG_CONF);
if (status < 0) {
dev_dbg(&client->dev, "Can't read config? %d\n", status);
return status;
}
data->orig_conf = status;
new = status & ~clr_mask;
new |= set_mask;
if (status != new)
lm75_write_value(client, LM75_REG_CONF, new);
dev_dbg(&client->dev, "Config %02x\n", new);
/* Register sysfs hooks */
status = sysfs_create_group(&client->dev.kobj, &lm75_group);
if (status)
return status;
data->hwmon_dev = hwmon_device_register(&client->dev);
if (IS_ERR(data->hwmon_dev)) {
status = PTR_ERR(data->hwmon_dev);
goto exit_remove;
}
data->tz = thermal_zone_of_sensor_register(&client->dev,
0,
&client->dev,
lm75_read_temp, NULL);
if (IS_ERR(data->tz))
data->tz = NULL;
dev_info(&client->dev, "%s: sensor '%s'\n",
dev_name(data->hwmon_dev), client->name);
return 0;
exit_remove:
sysfs_remove_group(&client->dev.kobj, &lm75_group);
return status;
}
static int lm75_remove(struct i2c_client *client)
{
struct lm75_data *data = i2c_get_clientdata(client);
thermal_zone_of_sensor_unregister(&client->dev, data->tz);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &lm75_group);
lm75_write_value(client, LM75_REG_CONF, data->orig_conf);
return 0;
}
static const struct i2c_device_id lm75_ids[] = {
{ "adt75", adt75, },
{ "ds1775", ds1775, },
{ "ds75", ds75, },
{ "ds7505", ds7505, },
{ "g751", g751, },
{ "lm75", lm75, },
{ "lm75a", lm75a, },
{ "max6625", max6625, },
{ "max6626", max6626, },
{ "mcp980x", mcp980x, },
{ "stds75", stds75, },
{ "tcn75", tcn75, },
{ "tmp100", tmp100, },
{ "tmp101", tmp101, },
{ "tmp105", tmp105, },
{ "tmp175", tmp175, },
{ "tmp275", tmp275, },
{ "tmp75", tmp75, },
{ /* 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;
}
/* 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 = lm75_read_value(client, LM75_REG_CONF);
if (status < 0) {
dev_dbg(&client->dev, "Can't read config? %d\n", status);
return status;
}
status = status | LM75_SHUTDOWN;
lm75_write_value(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 = lm75_read_value(client, LM75_REG_CONF);
if (status < 0) {
dev_dbg(&client->dev, "Can't read config? %d\n", status);
return status;
}
status = status & ~LM75_SHUTDOWN;
lm75_write_value(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,
.remove = lm75_remove,
.id_table = lm75_ids,
.detect = lm75_detect,
.address_list = normal_i2c,
};
/*-----------------------------------------------------------------------*/
/* register access */
/*
* All registers are word-sized, except for the configuration register.
* LM75 uses a high-byte first convention, which is exactly opposite to
* the SMBus standard.
*/
static int lm75_read_value(struct i2c_client *client, u8 reg)
{
if (reg == LM75_REG_CONF)
return i2c_smbus_read_byte_data(client, reg);
else
return i2c_smbus_read_word_swapped(client, reg);
}
static int lm75_write_value(struct i2c_client *client, u8 reg, u16 value)
{
if (reg == LM75_REG_CONF)
return i2c_smbus_write_byte_data(client, reg, value);
else
return i2c_smbus_write_word_swapped(client, reg, value);
}
static struct lm75_data *lm75_update_device(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct lm75_data *data = i2c_get_clientdata(client);
struct lm75_data *ret = data;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + data->sample_time)
|| !data->valid) {
int i;
dev_dbg(&client->dev, "Starting lm75 update\n");
for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
int status;
status = lm75_read_value(client, LM75_REG_TEMP[i]);
if (unlikely(status < 0)) {
dev_dbg(dev,
"LM75: Failed to read value: reg %d, error %d\n",
LM75_REG_TEMP[i], status);
ret = ERR_PTR(status);
data->valid = 0;
goto abort;
}
data->temp[i] = status;
}
data->last_updated = jiffies;
data->valid = 1;
}
abort:
mutex_unlock(&data->update_lock);
return ret;
}
module_i2c_driver(lm75_driver);
MODULE_AUTHOR("Frodo Looijaard <frodol@dds.nl>");
MODULE_DESCRIPTION("LM75 driver");
MODULE_LICENSE("GPL");