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linux/drivers/hwmon/lm95245.c
Guenter Roeck a41a8927e7 hwmon: (lm95245) Make temp2_crit_hyst read-only 
The hysteresis register is shared among both temperature sensors.
This means changing one also affects the other. To avoid confusion,
established way to express this is to make only the first instance writable
and keep all other instances as read-only. Otherwise users may be
confused that changing the second writable value also affects the first,
while it is more obvious that a writable value may affect a different
read-only value.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
2014-03-03 08:01:06 -08:00

508 lines
13 KiB
C
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/*
* Copyright (C) 2011 Alexander Stein <alexander.stein@systec-electronic.com>
*
* The LM95245 is a sensor chip made by National Semiconductors.
* It reports up to two temperatures (its own plus an external one).
* Complete datasheet can be obtained from National's website at:
* http://www.national.com/ds.cgi/LM/LM95245.pdf
*
* This driver is based on lm95241.c
*
* 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/sysfs.h>
#define DEVNAME "lm95245"
static const unsigned short normal_i2c[] = {
0x18, 0x19, 0x29, 0x4c, 0x4d, I2C_CLIENT_END };
/* LM95245 registers */
/* general registers */
#define LM95245_REG_RW_CONFIG1 0x03
#define LM95245_REG_RW_CONVERS_RATE 0x04
#define LM95245_REG_W_ONE_SHOT 0x0F
/* diode configuration */
#define LM95245_REG_RW_CONFIG2 0xBF
#define LM95245_REG_RW_REMOTE_OFFH 0x11
#define LM95245_REG_RW_REMOTE_OFFL 0x12
/* status registers */
#define LM95245_REG_R_STATUS1 0x02
#define LM95245_REG_R_STATUS2 0x33
/* limit registers */
#define LM95245_REG_RW_REMOTE_OS_LIMIT 0x07
#define LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT 0x20
#define LM95245_REG_RW_REMOTE_TCRIT_LIMIT 0x19
#define LM95245_REG_RW_COMMON_HYSTERESIS 0x21
/* temperature signed */
#define LM95245_REG_R_LOCAL_TEMPH_S 0x00
#define LM95245_REG_R_LOCAL_TEMPL_S 0x30
#define LM95245_REG_R_REMOTE_TEMPH_S 0x01
#define LM95245_REG_R_REMOTE_TEMPL_S 0x10
/* temperature unsigned */
#define LM95245_REG_R_REMOTE_TEMPH_U 0x31
#define LM95245_REG_R_REMOTE_TEMPL_U 0x32
/* id registers */
#define LM95245_REG_R_MAN_ID 0xFE
#define LM95245_REG_R_CHIP_ID 0xFF
/* LM95245 specific bitfields */
#define CFG_STOP 0x40
#define CFG_REMOTE_TCRIT_MASK 0x10
#define CFG_REMOTE_OS_MASK 0x08
#define CFG_LOCAL_TCRIT_MASK 0x04
#define CFG_LOCAL_OS_MASK 0x02
#define CFG2_OS_A0 0x40
#define CFG2_DIODE_FAULT_OS 0x20
#define CFG2_DIODE_FAULT_TCRIT 0x10
#define CFG2_REMOTE_TT 0x08
#define CFG2_REMOTE_FILTER_DIS 0x00
#define CFG2_REMOTE_FILTER_EN 0x06
/* conversation rate in ms */
#define RATE_CR0063 0x00
#define RATE_CR0364 0x01
#define RATE_CR1000 0x02
#define RATE_CR2500 0x03
#define STATUS1_DIODE_FAULT 0x04
#define STATUS1_RTCRIT 0x02
#define STATUS1_LOC 0x01
#define MANUFACTURER_ID 0x01
#define DEFAULT_REVISION 0xB3
static const u8 lm95245_reg_address[] = {
LM95245_REG_R_LOCAL_TEMPH_S,
LM95245_REG_R_LOCAL_TEMPL_S,
LM95245_REG_R_REMOTE_TEMPH_S,
LM95245_REG_R_REMOTE_TEMPL_S,
LM95245_REG_R_REMOTE_TEMPH_U,
LM95245_REG_R_REMOTE_TEMPL_U,
LM95245_REG_RW_LOCAL_OS_TCRIT_LIMIT,
LM95245_REG_RW_REMOTE_TCRIT_LIMIT,
LM95245_REG_RW_COMMON_HYSTERESIS,
LM95245_REG_R_STATUS1,
};
/* Client data (each client gets its own) */
struct lm95245_data {
struct i2c_client *client;
struct mutex update_lock;
unsigned long last_updated; /* in jiffies */
unsigned long interval; /* in msecs */
bool valid; /* zero until following fields are valid */
/* registers values */
u8 regs[ARRAY_SIZE(lm95245_reg_address)];
u8 config1, config2;
};
/* Conversions */
static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
{
return val_h * 1000 + val_l * 1000 / 256;
}
static int temp_from_reg_signed(u8 val_h, u8 val_l)
{
if (val_h & 0x80)
return (val_h - 0x100) * 1000;
return temp_from_reg_unsigned(val_h, val_l);
}
static struct lm95245_data *lm95245_update_device(struct device *dev)
{
struct lm95245_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated
+ msecs_to_jiffies(data->interval)) || !data->valid) {
int i;
for (i = 0; i < ARRAY_SIZE(lm95245_reg_address); i++)
data->regs[i]
= i2c_smbus_read_byte_data(client,
lm95245_reg_address[i]);
data->last_updated = jiffies;
data->valid = 1;
}
mutex_unlock(&data->update_lock);
return data;
}
static unsigned long lm95245_read_conversion_rate(struct i2c_client *client)
{
int rate;
unsigned long interval;
rate = i2c_smbus_read_byte_data(client, LM95245_REG_RW_CONVERS_RATE);
switch (rate) {
case RATE_CR0063:
interval = 63;
break;
case RATE_CR0364:
interval = 364;
break;
case RATE_CR1000:
interval = 1000;
break;
case RATE_CR2500:
default:
interval = 2500;
break;
}
return interval;
}
static unsigned long lm95245_set_conversion_rate(struct i2c_client *client,
unsigned long interval)
{
int rate;
if (interval <= 63) {
interval = 63;
rate = RATE_CR0063;
} else if (interval <= 364) {
interval = 364;
rate = RATE_CR0364;
} else if (interval <= 1000) {
interval = 1000;
rate = RATE_CR1000;
} else {
interval = 2500;
rate = RATE_CR2500;
}
i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONVERS_RATE, rate);
return interval;
}
/* Sysfs stuff */
static ssize_t show_input(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct lm95245_data *data = lm95245_update_device(dev);
int temp;
int index = to_sensor_dev_attr(attr)->index;
/*
* Index 0 (Local temp) is always signed
* Index 2 (Remote temp) has both signed and unsigned data
* use signed calculation for remote if signed bit is set
*/
if (index == 0 || data->regs[index] & 0x80)
temp = temp_from_reg_signed(data->regs[index],
data->regs[index + 1]);
else
temp = temp_from_reg_unsigned(data->regs[index + 2],
data->regs[index + 3]);
return snprintf(buf, PAGE_SIZE - 1, "%d\n", temp);
}
static ssize_t show_limit(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct lm95245_data *data = lm95245_update_device(dev);
int index = to_sensor_dev_attr(attr)->index;
return snprintf(buf, PAGE_SIZE - 1, "%d\n",
data->regs[index] * 1000);
}
static ssize_t set_limit(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct lm95245_data *data = dev_get_drvdata(dev);
int index = to_sensor_dev_attr(attr)->index;
struct i2c_client *client = data->client;
unsigned long val;
if (kstrtoul(buf, 10, &val) < 0)
return -EINVAL;
val /= 1000;
val = clamp_val(val, 0, (index == 6 ? 127 : 255));
mutex_lock(&data->update_lock);
data->valid = 0;
i2c_smbus_write_byte_data(client, lm95245_reg_address[index], val);
mutex_unlock(&data->update_lock);
return count;
}
static ssize_t show_crit_hyst(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct lm95245_data *data = lm95245_update_device(dev);
int index = to_sensor_dev_attr(attr)->index;
int hyst = data->regs[index] - data->regs[8];
return snprintf(buf, PAGE_SIZE - 1, "%d\n", hyst * 1000);
}
static ssize_t set_crit_hyst(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct lm95245_data *data = dev_get_drvdata(dev);
int index = to_sensor_dev_attr(attr)->index;
struct i2c_client *client = data->client;
unsigned long val;
int hyst, limit;
if (kstrtoul(buf, 10, &val) < 0)
return -EINVAL;
mutex_lock(&data->update_lock);
limit = i2c_smbus_read_byte_data(client, lm95245_reg_address[index]);
hyst = limit - val / 1000;
hyst = clamp_val(hyst, 0, 31);
data->regs[8] = hyst;
/* shared crit hysteresis */
i2c_smbus_write_byte_data(client, LM95245_REG_RW_COMMON_HYSTERESIS,
hyst);
mutex_unlock(&data->update_lock);
return count;
}
static ssize_t show_type(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct lm95245_data *data = dev_get_drvdata(dev);
return snprintf(buf, PAGE_SIZE - 1,
data->config2 & CFG2_REMOTE_TT ? "1\n" : "2\n");
}
static ssize_t set_type(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct lm95245_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
unsigned long val;
if (kstrtoul(buf, 10, &val) < 0)
return -EINVAL;
if (val != 1 && val != 2)
return -EINVAL;
mutex_lock(&data->update_lock);
if (val == 1)
data->config2 |= CFG2_REMOTE_TT;
else
data->config2 &= ~CFG2_REMOTE_TT;
data->valid = 0;
i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG2,
data->config2);
mutex_unlock(&data->update_lock);
return count;
}
static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct lm95245_data *data = lm95245_update_device(dev);
int index = to_sensor_dev_attr(attr)->index;
return snprintf(buf, PAGE_SIZE - 1, "%d\n",
!!(data->regs[9] & index));
}
static ssize_t show_interval(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct lm95245_data *data = lm95245_update_device(dev);
return snprintf(buf, PAGE_SIZE - 1, "%lu\n", data->interval);
}
static ssize_t set_interval(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct lm95245_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
unsigned long val;
if (kstrtoul(buf, 10, &val) < 0)
return -EINVAL;
mutex_lock(&data->update_lock);
data->interval = lm95245_set_conversion_rate(client, val);
mutex_unlock(&data->update_lock);
return count;
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_input, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO, show_limit,
set_limit, 6);
static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IWUSR | S_IRUGO, show_crit_hyst,
set_crit_hyst, 6);
static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
STATUS1_LOC);
static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_limit,
set_limit, 7);
static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IRUGO, show_crit_hyst, NULL, 7);
static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL,
STATUS1_RTCRIT);
static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type,
set_type, 0);
static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_alarm, NULL,
STATUS1_DIODE_FAULT);
static DEVICE_ATTR(update_interval, S_IWUSR | S_IRUGO, show_interval,
set_interval);
static struct attribute *lm95245_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_crit_alarm.dev_attr.attr,
&sensor_dev_attr_temp2_input.dev_attr.attr,
&sensor_dev_attr_temp2_crit.dev_attr.attr,
&sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
&sensor_dev_attr_temp2_crit_alarm.dev_attr.attr,
&sensor_dev_attr_temp2_type.dev_attr.attr,
&sensor_dev_attr_temp2_fault.dev_attr.attr,
&dev_attr_update_interval.attr,
NULL
};
ATTRIBUTE_GROUPS(lm95245);
/* Return 0 if detection is successful, -ENODEV otherwise */
static int lm95245_detect(struct i2c_client *new_client,
struct i2c_board_info *info)
{
struct i2c_adapter *adapter = new_client->adapter;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
return -ENODEV;
if (i2c_smbus_read_byte_data(new_client, LM95245_REG_R_MAN_ID)
!= MANUFACTURER_ID
|| i2c_smbus_read_byte_data(new_client, LM95245_REG_R_CHIP_ID)
!= DEFAULT_REVISION)
return -ENODEV;
strlcpy(info->type, DEVNAME, I2C_NAME_SIZE);
return 0;
}
static void lm95245_init_client(struct i2c_client *client,
struct lm95245_data *data)
{
data->interval = lm95245_read_conversion_rate(client);
data->config1 = i2c_smbus_read_byte_data(client,
LM95245_REG_RW_CONFIG1);
data->config2 = i2c_smbus_read_byte_data(client,
LM95245_REG_RW_CONFIG2);
if (data->config1 & CFG_STOP) {
/* Clear the standby bit */
data->config1 &= ~CFG_STOP;
i2c_smbus_write_byte_data(client, LM95245_REG_RW_CONFIG1,
data->config1);
}
}
static int lm95245_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct lm95245_data *data;
struct device *hwmon_dev;
data = devm_kzalloc(dev, sizeof(struct lm95245_data), GFP_KERNEL);
if (!data)
return -ENOMEM;
data->client = client;
mutex_init(&data->update_lock);
/* Initialize the LM95245 chip */
lm95245_init_client(client, data);
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
data,
lm95245_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
/* Driver data (common to all clients) */
static const struct i2c_device_id lm95245_id[] = {
{ DEVNAME, 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, lm95245_id);
static struct i2c_driver lm95245_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = DEVNAME,
},
.probe = lm95245_probe,
.id_table = lm95245_id,
.detect = lm95245_detect,
.address_list = normal_i2c,
};
module_i2c_driver(lm95245_driver);
MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
MODULE_DESCRIPTION("LM95245 sensor driver");
MODULE_LICENSE("GPL");
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