linux/drivers/hwmon/lm92.c
Julia Lawall 3dba95dfd4 hwmon: (lm92) use permission-specific DEVICE_ATTR variants
Use DEVICE_ATTR_RO for read-only attributes. This simplifies the source
code, improves readbility, and reduces the chance of inconsistencies.

The conversion was done automatically using coccinelle. It was validated
by compiling both the old and the new source code and comparing its text,
data, and bss size.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
[groeck: Update description]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-01-02 10:19:45 -08:00

412 lines
12 KiB
C

/*
* lm92 - Hardware monitoring driver
* Copyright (C) 2005-2008 Jean Delvare <jdelvare@suse.de>
*
* Based on the lm90 driver, with some ideas taken from the lm_sensors
* lm92 driver as well.
*
* The LM92 is a sensor chip made by National Semiconductor. It reports
* its own temperature with a 0.0625 deg resolution and a 0.33 deg
* accuracy. Complete datasheet can be obtained from National's website
* at:
* http://www.national.com/pf/LM/LM92.html
*
* This driver also supports the MAX6635 sensor chip made by Maxim.
* This chip is compatible with the LM92, but has a lesser accuracy
* (1.0 deg). Complete datasheet can be obtained from Maxim's website
* at:
* http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3074
*
* Since the LM92 was the first chipset supported by this driver, most
* comments will refer to this chipset, but are actually general and
* concern all supported chipsets, unless mentioned otherwise.
*
* Support could easily be added for the National Semiconductor LM76
* and Maxim MAX6633 and MAX6634 chips, which are mostly compatible
* with the LM92.
*
* 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/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/jiffies.h>
/*
* The LM92 and MAX6635 have 2 two-state pins for address selection,
* resulting in 4 possible addresses.
*/
static const unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b,
I2C_CLIENT_END };
/* The LM92 registers */
#define LM92_REG_CONFIG 0x01 /* 8-bit, RW */
#define LM92_REG_TEMP 0x00 /* 16-bit, RO */
#define LM92_REG_TEMP_HYST 0x02 /* 16-bit, RW */
#define LM92_REG_TEMP_CRIT 0x03 /* 16-bit, RW */
#define LM92_REG_TEMP_LOW 0x04 /* 16-bit, RW */
#define LM92_REG_TEMP_HIGH 0x05 /* 16-bit, RW */
#define LM92_REG_MAN_ID 0x07 /* 16-bit, RO, LM92 only */
/*
* The LM92 uses signed 13-bit values with LSB = 0.0625 degree Celsius,
* left-justified in 16-bit registers. No rounding is done, with such
* a resolution it's just not worth it. Note that the MAX6635 doesn't
* make use of the 4 lower bits for limits (i.e. effective resolution
* for limits is 1 degree Celsius).
*/
static inline int TEMP_FROM_REG(s16 reg)
{
return reg / 8 * 625 / 10;
}
static inline s16 TEMP_TO_REG(long val)
{
val = clamp_val(val, -60000, 160000);
return val * 10 / 625 * 8;
}
/* Alarm flags are stored in the 3 LSB of the temperature register */
static inline u8 ALARMS_FROM_REG(s16 reg)
{
return reg & 0x0007;
}
enum temp_index {
t_input,
t_crit,
t_min,
t_max,
t_hyst,
t_num_regs
};
static const u8 regs[t_num_regs] = {
[t_input] = LM92_REG_TEMP,
[t_crit] = LM92_REG_TEMP_CRIT,
[t_min] = LM92_REG_TEMP_LOW,
[t_max] = LM92_REG_TEMP_HIGH,
[t_hyst] = LM92_REG_TEMP_HYST,
};
/* Client data (each client gets its own) */
struct lm92_data {
struct i2c_client *client;
struct mutex update_lock;
char valid; /* zero until following fields are valid */
unsigned long last_updated; /* in jiffies */
/* registers values */
s16 temp[t_num_regs]; /* index with enum temp_index */
};
/*
* Sysfs attributes and callback functions
*/
static struct lm92_data *lm92_update_device(struct device *dev)
{
struct lm92_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int i;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ)
|| !data->valid) {
dev_dbg(&client->dev, "Updating lm92 data\n");
for (i = 0; i < t_num_regs; i++) {
data->temp[i] =
i2c_smbus_read_word_swapped(client, regs[i]);
}
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct lm92_data *data = lm92_update_device(dev);
return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index]));
}
static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
const char *buf, size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct lm92_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
int nr = attr->index;
long val;
int err;
err = kstrtol(buf, 10, &val);
if (err)
return err;
mutex_lock(&data->update_lock);
data->temp[nr] = TEMP_TO_REG(val);
i2c_smbus_write_word_swapped(client, regs[nr], data->temp[nr]);
mutex_unlock(&data->update_lock);
return count;
}
static ssize_t show_temp_hyst(struct device *dev,
struct device_attribute *devattr, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct lm92_data *data = lm92_update_device(dev);
return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[attr->index])
- TEMP_FROM_REG(data->temp[t_hyst]));
}
static ssize_t temp1_min_hyst_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct lm92_data *data = lm92_update_device(dev);
return sprintf(buf, "%d\n", TEMP_FROM_REG(data->temp[t_min])
+ TEMP_FROM_REG(data->temp[t_hyst]));
}
static ssize_t set_temp_hyst(struct device *dev,
struct device_attribute *devattr,
const char *buf, size_t count)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct lm92_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
long val;
int err;
err = kstrtol(buf, 10, &val);
if (err)
return err;
val = clamp_val(val, -120000, 220000);
mutex_lock(&data->update_lock);
data->temp[t_hyst] =
TEMP_TO_REG(TEMP_FROM_REG(data->temp[attr->index]) - val);
i2c_smbus_write_word_swapped(client, LM92_REG_TEMP_HYST,
data->temp[t_hyst]);
mutex_unlock(&data->update_lock);
return count;
}
static ssize_t alarms_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct lm92_data *data = lm92_update_device(dev);
return sprintf(buf, "%d\n", ALARMS_FROM_REG(data->temp[t_input]));
}
static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
char *buf)
{
int bitnr = to_sensor_dev_attr(attr)->index;
struct lm92_data *data = lm92_update_device(dev);
return sprintf(buf, "%d\n", (data->temp[t_input] >> bitnr) & 1);
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, t_input);
static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_temp, set_temp,
t_crit);
static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_temp_hyst,
set_temp_hyst, t_crit);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp,
t_min);
static DEVICE_ATTR_RO(temp1_min_hyst);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp,
t_max);
static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_temp_hyst, NULL, t_max);
static DEVICE_ATTR_RO(alarms);
static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 2);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
/*
* Detection and registration
*/
static void lm92_init_client(struct i2c_client *client)
{
u8 config;
/* Start the conversions if needed */
config = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
if (config & 0x01)
i2c_smbus_write_byte_data(client, LM92_REG_CONFIG,
config & 0xFE);
}
/*
* The MAX6635 has no identification register, so we have to use tricks
* to identify it reliably. This is somewhat slow.
* Note that we do NOT rely on the 2 MSB of the configuration register
* always reading 0, as suggested by the datasheet, because it was once
* reported not to be true.
*/
static int max6635_check(struct i2c_client *client)
{
u16 temp_low, temp_high, temp_hyst, temp_crit;
u8 conf;
int i;
/*
* No manufacturer ID register, so a read from this address will
* always return the last read value.
*/
temp_low = i2c_smbus_read_word_data(client, LM92_REG_TEMP_LOW);
if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_low)
return 0;
temp_high = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HIGH);
if (i2c_smbus_read_word_data(client, LM92_REG_MAN_ID) != temp_high)
return 0;
/* Limits are stored as integer values (signed, 9-bit). */
if ((temp_low & 0x7f00) || (temp_high & 0x7f00))
return 0;
temp_hyst = i2c_smbus_read_word_data(client, LM92_REG_TEMP_HYST);
temp_crit = i2c_smbus_read_word_data(client, LM92_REG_TEMP_CRIT);
if ((temp_hyst & 0x7f00) || (temp_crit & 0x7f00))
return 0;
/*
* Registers addresses were found to cycle over 16-byte boundaries.
* We don't test all registers with all offsets so as to save some
* reads and time, but this should still be sufficient to dismiss
* non-MAX6635 chips.
*/
conf = i2c_smbus_read_byte_data(client, LM92_REG_CONFIG);
for (i = 16; i < 96; i *= 2) {
if (temp_hyst != i2c_smbus_read_word_data(client,
LM92_REG_TEMP_HYST + i - 16)
|| temp_crit != i2c_smbus_read_word_data(client,
LM92_REG_TEMP_CRIT + i)
|| temp_low != i2c_smbus_read_word_data(client,
LM92_REG_TEMP_LOW + i + 16)
|| temp_high != i2c_smbus_read_word_data(client,
LM92_REG_TEMP_HIGH + i + 32)
|| conf != i2c_smbus_read_byte_data(client,
LM92_REG_CONFIG + i))
return 0;
}
return 1;
}
static struct attribute *lm92_attrs[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp1_crit.dev_attr.attr,
&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
&sensor_dev_attr_temp1_min.dev_attr.attr,
&dev_attr_temp1_min_hyst.attr,
&sensor_dev_attr_temp1_max.dev_attr.attr,
&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
&dev_attr_alarms.attr,
&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
NULL
};
ATTRIBUTE_GROUPS(lm92);
/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm92_detect(struct i2c_client *new_client,
struct i2c_board_info *info)
{
struct i2c_adapter *adapter = new_client->adapter;
u8 config;
u16 man_id;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
| I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
config = i2c_smbus_read_byte_data(new_client, LM92_REG_CONFIG);
man_id = i2c_smbus_read_word_data(new_client, LM92_REG_MAN_ID);
if ((config & 0xe0) == 0x00 && man_id == 0x0180)
pr_info("lm92: Found National Semiconductor LM92 chip\n");
else if (max6635_check(new_client))
pr_info("lm92: Found Maxim MAX6635 chip\n");
else
return -ENODEV;
strlcpy(info->type, "lm92", I2C_NAME_SIZE);
return 0;
}
static int lm92_probe(struct i2c_client *new_client,
const struct i2c_device_id *id)
{
struct device *hwmon_dev;
struct lm92_data *data;
data = devm_kzalloc(&new_client->dev, sizeof(struct lm92_data),
GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = new_client;
mutex_init(&data->update_lock);
/* Initialize the chipset */
lm92_init_client(new_client);
hwmon_dev = devm_hwmon_device_register_with_groups(&new_client->dev,
new_client->name,
data, lm92_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
/*
* Module and driver stuff
*/
static const struct i2c_device_id lm92_id[] = {
{ "lm92", 0 },
/* max6635 could be added here */
{ }
};
MODULE_DEVICE_TABLE(i2c, lm92_id);
static struct i2c_driver lm92_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "lm92",
},
.probe = lm92_probe,
.id_table = lm92_id,
.detect = lm92_detect,
.address_list = normal_i2c,
};
module_i2c_driver(lm92_driver);
MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
MODULE_DESCRIPTION("LM92/MAX6635 driver");
MODULE_LICENSE("GPL");