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hwmon: Support for Dallas Semiconductor DS620

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Driver for Dallas Semiconductor DS620 temperature sensor and thermostat

Signed-off-by: Roland Stigge <stigge@antcom.de>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
This commit is contained in:
Roland Stigge 2011-01-09 09:31:39 -05:00 committed by Guenter Roeck
parent 430400b863
commit 6099469805
5 changed files with 403 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

34
Documentation/hwmon/ds620 Normal file
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Kernel driver ds620
===================
Supported chips:
* Dallas Semiconductor DS620
Prefix: 'ds620'
Datasheet: Publicly available at the Dallas Semiconductor website
http://www.dalsemi.com/
Authors:
Roland Stigge <stigge@antcom.de>
based on ds1621.c by
Christian W. Zuckschwerdt <zany@triq.net>
Description
-----------
The DS620 is a (one instance) digital thermometer and thermostat. It has both
high and low temperature limits which can be user defined (i.e. programmed
into non-volatile on-chip registers). Temperature range is -55 degree Celsius
to +125. Between 0 and 70 degree Celsius, accuracy is 0.5 Kelvin. The value
returned via sysfs displays post decimal positions.
The thermostat function works as follows: When configured via platform_data
(struct ds620_platform_data) .pomode == 0 (default), the thermostat output pin
PO is always low. If .pomode == 1, the thermostat is in PO_LOW mode. I.e., the
output pin PO becomes active when the temperature falls below temp1_min and
stays active until the temperature goes above temp1_max.
Likewise, with .pomode == 2, the thermostat is in PO_HIGH mode. I.e., the PO
output pin becomes active when the temperature goes above temp1_max and stays
active until the temperature falls below temp1_min.
The PO output pin of the DS620 operates active-low.

10
drivers/hwmon/Kconfig
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@ -274,6 +274,16 @@ config SENSORS_ATXP1
This driver can also be built as a module. If so, the module This driver can also be built as a module. If so, the module
will be called atxp1. will be called atxp1.
config SENSORS_DS620
tristate "Dallas Semiconductor DS620"
depends on I2C
help
If you say yes here you get support for Dallas Semiconductor
DS620 sensor chip.
This driver can also be built as a module. If so, the module
will be called ds620.
config SENSORS_DS1621 config SENSORS_DS1621
tristate "Dallas Semiconductor DS1621 and DS1625" tristate "Dallas Semiconductor DS1621 and DS1625"
depends on I2C depends on I2C

1
drivers/hwmon/Makefile
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@ -41,6 +41,7 @@ obj-$(CONFIG_SENSORS_ATXP1) += atxp1.o
obj-$(CONFIG_SENSORS_CORETEMP) += coretemp.o obj-$(CONFIG_SENSORS_CORETEMP) += coretemp.o
obj-$(CONFIG_SENSORS_PKGTEMP) += pkgtemp.o obj-$(CONFIG_SENSORS_PKGTEMP) += pkgtemp.o
obj-$(CONFIG_SENSORS_DME1737) += dme1737.o obj-$(CONFIG_SENSORS_DME1737) += dme1737.o
obj-$(CONFIG_SENSORS_DS620) += ds620.o
obj-$(CONFIG_SENSORS_DS1621) += ds1621.o obj-$(CONFIG_SENSORS_DS1621) += ds1621.o
obj-$(CONFIG_SENSORS_EMC1403) += emc1403.o obj-$(CONFIG_SENSORS_EMC1403) += emc1403.o
obj-$(CONFIG_SENSORS_EMC2103) += emc2103.o obj-$(CONFIG_SENSORS_EMC2103) += emc2103.o

337
drivers/hwmon/ds620.c Normal file
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/*
* ds620.c - Support for temperature sensor and thermostat DS620
*
* Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
*
* based on ds1621.c by Christian W. Zuckschwerdt <zany@triq.net>
*
* 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>
#include <linux/i2c/ds620.h>
/*
* Many DS620 constants specified below
* 15 14 13 12 11 10 09 08
* |Done|NVB |THF |TLF |R1 |R0 |AUTOC|1SHOT|
*
* 07 06 05 04 03 02 01 00
* |PO2 |PO1 |A2 |A1 |A0 | | | |
*/
#define DS620_REG_CONFIG_DONE 0x8000
#define DS620_REG_CONFIG_NVB 0x4000
#define DS620_REG_CONFIG_THF 0x2000
#define DS620_REG_CONFIG_TLF 0x1000
#define DS620_REG_CONFIG_R1 0x0800
#define DS620_REG_CONFIG_R0 0x0400
#define DS620_REG_CONFIG_AUTOC 0x0200
#define DS620_REG_CONFIG_1SHOT 0x0100
#define DS620_REG_CONFIG_PO2 0x0080
#define DS620_REG_CONFIG_PO1 0x0040
#define DS620_REG_CONFIG_A2 0x0020
#define DS620_REG_CONFIG_A1 0x0010
#define DS620_REG_CONFIG_A0 0x0008
/* The DS620 registers */
static const u8 DS620_REG_TEMP[3] = {
0xAA, /* input, word, RO */
0xA2, /* min, word, RW */
0xA0, /* max, word, RW */
};
#define DS620_REG_CONF 0xAC /* word, RW */
#define DS620_COM_START 0x51 /* no data */
#define DS620_COM_STOP 0x22 /* no data */
/* Each client has this additional data */
struct ds620_data {
struct device *hwmon_dev;
struct mutex update_lock;
char valid; /* !=0 if following fields are valid */
unsigned long last_updated; /* In jiffies */
u16 temp[3]; /* Register values, word */
};
/*
* Temperature registers are word-sized.
* DS620 uses a high-byte first convention, which is exactly opposite to
* the SMBus standard.
*/
static int ds620_read_temp(struct i2c_client *client, u8 reg)
{
int ret;
ret = i2c_smbus_read_word_data(client, reg);
if (ret < 0)
return ret;
return swab16(ret);
}
static int ds620_write_temp(struct i2c_client *client, u8 reg, u16 value)
{
return i2c_smbus_write_word_data(client, reg, swab16(value));
}
static void ds620_init_client(struct i2c_client *client)
{
struct ds620_platform_data *ds620_info = client->dev.platform_data;
u16 conf, new_conf;
new_conf = conf =
swab16(i2c_smbus_read_word_data(client, DS620_REG_CONF));
/* switch to continuous conversion mode */
new_conf &= ~DS620_REG_CONFIG_1SHOT;
/* already high at power-on, but don't trust the BIOS! */
new_conf |= DS620_REG_CONFIG_PO2;
/* thermostat mode according to platform data */
if (ds620_info && ds620_info->pomode == 1)
new_conf &= ~DS620_REG_CONFIG_PO1; /* PO_LOW */
else if (ds620_info && ds620_info->pomode == 2)
new_conf |= DS620_REG_CONFIG_PO1; /* PO_HIGH */
else
new_conf &= ~DS620_REG_CONFIG_PO2; /* always low */
/* with highest precision */
new_conf |= DS620_REG_CONFIG_R1 | DS620_REG_CONFIG_R0;
if (conf != new_conf)
i2c_smbus_write_word_data(client, DS620_REG_CONF,
swab16(new_conf));
/* start conversion */
i2c_smbus_write_byte(client, DS620_COM_START);
}
static struct ds620_data *ds620_update_client(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds620_data *data = i2c_get_clientdata(client);
struct ds620_data *ret = data;
mutex_lock(&data->update_lock);
if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
|| !data->valid) {
int i;
int res;
dev_dbg(&client->dev, "Starting ds620 update\n");
for (i = 0; i < ARRAY_SIZE(data->temp); i++) {
res = ds620_read_temp(client,
DS620_REG_TEMP[i]);
if (res < 0) {
ret = ERR_PTR(res);
goto abort;
}
data->temp[i] = res;
}
data->last_updated = jiffies;
data->valid = 1;
}
abort:
mutex_unlock(&data->update_lock);
return ret;
}
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 ds620_data *data = ds620_update_client(dev);
if (IS_ERR(data))
return PTR_ERR(data);
return sprintf(buf, "%d\n", ((data->temp[attr->index] / 8) * 625) / 10);
}
static ssize_t set_temp(struct device *dev, struct device_attribute *da,
const char *buf, size_t count)
{
int res;
long val;
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct i2c_client *client = to_i2c_client(dev);
struct ds620_data *data = i2c_get_clientdata(client);
res = strict_strtol(buf, 10, &val);
if (res)
return res;
val = (val * 10 / 625) * 8;
mutex_lock(&data->update_lock);
data->temp[attr->index] = val;
ds620_write_temp(client, DS620_REG_TEMP[attr->index],
data->temp[attr->index]);
mutex_unlock(&data->update_lock);
return count;
}
static ssize_t show_alarm(struct device *dev, struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct ds620_data *data = ds620_update_client(dev);
struct i2c_client *client = to_i2c_client(dev);
u16 conf, new_conf;
int res;
if (IS_ERR(data))
return PTR_ERR(data);
/* reset alarms if necessary */
res = i2c_smbus_read_word_data(client, DS620_REG_CONF);
if (res < 0)
return res;
conf = swab16(res);
new_conf = conf;
new_conf &= ~attr->index;
if (conf != new_conf) {
res = i2c_smbus_write_word_data(client, DS620_REG_CONF,
swab16(new_conf));
if (res < 0)
return res;
}
return sprintf(buf, "%d\n", !!(conf & attr->index));
}
static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO, show_temp, set_temp, 1);
static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, show_temp, set_temp, 2);
static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL,
DS620_REG_CONFIG_TLF);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL,
DS620_REG_CONFIG_THF);
static struct attribute *ds620_attributes[] = {
&sensor_dev_attr_temp1_input.dev_attr.attr,
&sensor_dev_attr_temp1_min.dev_attr.attr,
&sensor_dev_attr_temp1_max.dev_attr.attr,
&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
NULL
};
static const struct attribute_group ds620_group = {
.attrs = ds620_attributes,
};
static int ds620_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ds620_data *data;
int err;
data = kzalloc(sizeof(struct ds620_data), GFP_KERNEL);
if (!data) {
err = -ENOMEM;
goto exit;
}
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
/* Initialize the DS620 chip */
ds620_init_client(client);
/* Register sysfs hooks */
err = sysfs_create_group(&client->dev.kobj, &ds620_group);
if (err)
goto exit_free;
data->hwmon_dev = hwmon_device_register(&client->dev);
if (IS_ERR(data->hwmon_dev)) {
err = PTR_ERR(data->hwmon_dev);
goto exit_remove_files;
}
dev_info(&client->dev, "temperature sensor found\n");
return 0;
exit_remove_files:
sysfs_remove_group(&client->dev.kobj, &ds620_group);
exit_free:
kfree(data);
exit:
return err;
}
static int ds620_remove(struct i2c_client *client)
{
struct ds620_data *data = i2c_get_clientdata(client);
hwmon_device_unregister(data->hwmon_dev);
sysfs_remove_group(&client->dev.kobj, &ds620_group);
kfree(data);
return 0;
}
static const struct i2c_device_id ds620_id[] = {
{"ds620", 0},
{}
};
MODULE_DEVICE_TABLE(i2c, ds620_id);
/* This is the driver that will be inserted */
static struct i2c_driver ds620_driver = {
.class = I2C_CLASS_HWMON,
.driver = {
.name = "ds620",
},
.probe = ds620_probe,
.remove = ds620_remove,
.id_table = ds620_id,
};
static int __init ds620_init(void)
{
return i2c_add_driver(&ds620_driver);
}
static void __exit ds620_exit(void)
{
i2c_del_driver(&ds620_driver);
}
MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
MODULE_DESCRIPTION("DS620 driver");
MODULE_LICENSE("GPL");
module_init(ds620_init);
module_exit(ds620_exit);

21
include/linux/i2c/ds620.h Normal file
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#ifndef _LINUX_DS620_H
#define _LINUX_DS620_H
#include <linux/types.h>
#include <linux/i2c.h>
/* platform data for the DS620 temperature sensor and thermostat */
struct ds620_platform_data {
/*
* Thermostat output pin PO mode:
* 0 = always low (default)
* 1 = PO_LOW
* 2 = PO_HIGH
*
* (see Documentation/hwmon/ds620)
*/
int pomode;
};
#endif /* _LINUX_DS620_H */