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/*
* ads1015.c - lm_sensors driver for ads1015 12-bit 4-input ADC
* (C) Copyright 2010
* Dirk Eibach, Guntermann & Drunck GmbH <eibach@gdsys.de>
*
* Based on the ads7828 driver by Steve Hardy.
*
* Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads1015.pdf
*
* 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/delay.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/i2c/ads1015.h>
/* ADS1015 registers */
enum {
ADS1015_CONVERSION = 0,
ADS1015_CONFIG = 1,
};
/* PGA fullscale voltages in mV */
static const unsigned int fullscale_table[8] = {
6144, 4096, 2048, 1024, 512, 256, 256, 256 };
#define ADS1015_CONFIG_CHANNELS 8
#define ADS1015_DEFAULT_CHANNELS 0xff
struct ads1015_data {
struct device *hwmon_dev;
struct mutex update_lock; /* mutex protect updates */
};
static s32 ads1015_read_reg(struct i2c_client *client, unsigned int reg)
{
s32 data = i2c_smbus_read_word_data(client, reg);
return (data < 0) ? data : swab16(data);
}
static s32 ads1015_write_reg(struct i2c_client *client, unsigned int reg,
u16 val)
{
return i2c_smbus_write_word_data(client, reg, swab16(val));
}
static int ads1015_read_value(struct i2c_client *client, unsigned int channel,
int *value)
{
u16 config;
s16 conversion;
unsigned int pga;
int fullscale;
unsigned int k;
struct ads1015_data *data = i2c_get_clientdata(client);
int res;
mutex_lock(&data->update_lock);
/* get fullscale voltage */
res = ads1015_read_reg(client, ADS1015_CONFIG);
if (res < 0)
goto err_unlock;
config = res;
pga = (config >> 9) & 0x0007;
fullscale = fullscale_table[pga];
/* set channel and start single conversion */
config &= ~(0x0007 << 12);
config |= (1 << 15) | (1 << 8) | (channel & 0x0007) << 12;
/* wait until conversion finished */
res = ads1015_write_reg(client, ADS1015_CONFIG, config);
if (res < 0)
goto err_unlock;
for (k = 0; k < 5; ++k) {
msleep(1);
res = ads1015_read_reg(client, ADS1015_CONFIG);
if (res < 0)
goto err_unlock;
config = res;
if (config & (1 << 15))
break;
}
if (k == 5) {
res = -EIO;
goto err_unlock;
}
res = ads1015_read_reg(client, ADS1015_CONVERSION);
if (res < 0)
goto err_unlock;
conversion = res;
mutex_unlock(&data->update_lock);
*value = DIV_ROUND_CLOSEST(conversion * fullscale, 0x7ff0);
return 0;
err_unlock:
mutex_unlock(&data->update_lock);
return res;
}
/* sysfs callback function */
static ssize_t show_in(struct device *dev, struct device_attribute *da,
char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
struct i2c_client *client = to_i2c_client(dev);
int in;
int res;
res = ads1015_read_value(client, attr->index, &in);
return (res < 0) ? res : sprintf(buf, "%d\n", in);
}
static const struct sensor_device_attribute ads1015_in[] = {
SENSOR_ATTR(in0_input, S_IRUGO, show_in, NULL, 0),
SENSOR_ATTR(in1_input, S_IRUGO, show_in, NULL, 1),
SENSOR_ATTR(in2_input, S_IRUGO, show_in, NULL, 2),
SENSOR_ATTR(in3_input, S_IRUGO, show_in, NULL, 3),
SENSOR_ATTR(in4_input, S_IRUGO, show_in, NULL, 4),
SENSOR_ATTR(in5_input, S_IRUGO, show_in, NULL, 5),
SENSOR_ATTR(in6_input, S_IRUGO, show_in, NULL, 6),
SENSOR_ATTR(in7_input, S_IRUGO, show_in, NULL, 7),
};
/*
* Driver interface
*/
static int ads1015_remove(struct i2c_client *client)
{
struct ads1015_data *data = i2c_get_clientdata(client);
int k;
hwmon_device_unregister(data->hwmon_dev);
for (k = 0; k < ADS1015_CONFIG_CHANNELS; ++k)
device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
kfree(data);
return 0;
}
static unsigned int ads1015_get_exported_channels(struct i2c_client *client)
{
struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
#ifdef CONFIG_OF
struct device_node *np = client->dev.of_node;
const __be32 *of_channels;
int of_channels_size;
#endif
/* prefer platform data */
if (pdata)
return pdata->exported_channels;
#ifdef CONFIG_OF
/* fallback on OF */
of_channels = of_get_property(np, "exported-channels",
&of_channels_size);
if (of_channels && (of_channels_size == sizeof(*of_channels)))
return be32_to_cpup(of_channels);
#endif
/* fallback on default configuration */
return ADS1015_DEFAULT_CHANNELS;
}
static int ads1015_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ads1015_data *data;
int err;
unsigned int exported_channels;
unsigned int k;
data = kzalloc(sizeof(struct ads1015_data), GFP_KERNEL);
if (!data) {
err = -ENOMEM;
goto exit;
}
i2c_set_clientdata(client, data);
mutex_init(&data->update_lock);
/* build sysfs attribute group */
exported_channels = ads1015_get_exported_channels(client);
for (k = 0; k < ADS1015_CONFIG_CHANNELS; ++k) {
if (!(exported_channels & (1<<k)))
continue;
err = device_create_file(&client->dev, &ads1015_in[k].dev_attr);
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;
}
return 0;
exit_remove:
for (k = 0; k < ADS1015_CONFIG_CHANNELS; ++k)
device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
exit_free:
kfree(data);
exit:
return err;
}
static const struct i2c_device_id ads1015_id[] = {
{ "ads1015", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, ads1015_id);
static struct i2c_driver ads1015_driver = {
.driver = {
.name = "ads1015",
},
.probe = ads1015_probe,
.remove = ads1015_remove,
.id_table = ads1015_id,
};
static int __init sensors_ads1015_init(void)
{
return i2c_add_driver(&ads1015_driver);
}
static void __exit sensors_ads1015_exit(void)
{
i2c_del_driver(&ads1015_driver);
}
MODULE_AUTHOR("Dirk Eibach <eibach@gdsys.de>");
MODULE_DESCRIPTION("ADS1015 driver");
MODULE_LICENSE("GPL");
module_init(sensors_ads1015_init);
module_exit(sensors_ads1015_exit);
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