- 根目录:
- drivers
- hwmon
- ads1015.c
/*
* 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 };
/* Data rates in samples per second */
static const unsigned int data_rate_table[8] = {
128, 250, 490, 920, 1600, 2400, 3300, 3300 };
#define ADS1015_DEFAULT_CHANNELS 0xff
#define ADS1015_DEFAULT_PGA 2
#define ADS1015_DEFAULT_DATA_RATE 4
struct ads1015_data {
struct device *hwmon_dev;
struct mutex update_lock; /* mutex protect updates */
struct ads1015_channel_data channel_data[ADS1015_CHANNELS];
};
static int ads1015_read_adc(struct i2c_client *client, unsigned int channel)
{
u16 config;
struct ads1015_data *data = i2c_get_clientdata(client);
unsigned int pga = data->channel_data[channel].pga;
unsigned int data_rate = data->channel_data[channel].data_rate;
unsigned int conversion_time_ms;
int res;
mutex_lock(&data->update_lock);
/* get channel parameters */
res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
if (res < 0)
goto err_unlock;
config = res;
conversion_time_ms = DIV_ROUND_UP(1000, data_rate_table[data_rate]);
/* setup and start single conversion */
config &= 0x001f;
config |= (1 << 15) | (1 << 8);
config |= (channel & 0x0007) << 12;
config |= (pga & 0x0007) << 9;
config |= (data_rate & 0x0007) << 5;
res = i2c_smbus_write_word_swapped(client, ADS1015_CONFIG, config);
if (res < 0)
goto err_unlock;
/* wait until conversion finished */
msleep(conversion_time_ms);
res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
if (res < 0)
goto err_unlock;
config = res;
if (!(config & (1 << 15))) {
/* conversion not finished in time */
res = -EIO;
goto err_unlock;
}
res = i2c_smbus_read_word_swapped(client, ADS1015_CONVERSION);
err_unlock:
mutex_unlock(&data->update_lock);
return res;
}
static int ads1015_reg_to_mv(struct i2c_client *client, unsigned int channel,
s16 reg)
{
struct ads1015_data *data = i2c_get_clientdata(client);
unsigned int pga = data->channel_data[channel].pga;
int fullscale = fullscale_table[pga];
return DIV_ROUND_CLOSEST(reg * fullscale, 0x7ff0);
}
/* 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 res;
int index = attr->index;
res = ads1015_read_adc(client, index);
if (res < 0)
return res;
return sprintf(buf, "%d\n", ads1015_reg_to_mv(client, index, res));
}
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_CHANNELS; ++k)
device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
kfree(data);
return 0;
}
#ifdef CONFIG_OF
static int ads1015_get_channels_config_of(struct i2c_client *client)
{
struct ads1015_data *data = i2c_get_clientdata(client);
struct device_node *node;
if (!client->dev.of_node
|| !of_get_next_child(client->dev.of_node, NULL))
return -EINVAL;
for_each_child_of_node(client->dev.of_node, node) {
const __be32 *property;
int len;
unsigned int channel;
unsigned int pga = ADS1015_DEFAULT_PGA;
unsigned int data_rate = ADS1015_DEFAULT_DATA_RATE;
property = of_get_property(node, "reg", &len);
if (!property || len != sizeof(int)) {
dev_err(&client->dev, "invalid reg on %s\n",
node->full_name);
continue;
}
channel = be32_to_cpup(property);
if (channel > ADS1015_CHANNELS) {
dev_err(&client->dev,
"invalid channel index %d on %s\n",
channel, node->full_name);
continue;
}
property = of_get_property(node, "ti,gain", &len);
if (property && len == sizeof(int)) {
pga = be32_to_cpup(property);
if (pga > 6) {
dev_err(&client->dev,
"invalid gain on %s\n",
node->full_name);
}
}
property = of_get_property(node, "ti,datarate", &len);
if (property && len == sizeof(int)) {
data_rate = be32_to_cpup(property);
if (data_rate > 7) {
dev_err(&client->dev,
"invalid data_rate on %s\n",
node->full_name);
}
}
data->channel_data[channel].enabled = true;
data->channel_data[channel].pga = pga;
data->channel_data[channel].data_rate = data_rate;
}
return 0;
}
#endif
static void ads1015_get_channels_config(struct i2c_client *client)
{
unsigned int k;
struct ads1015_data *data = i2c_get_clientdata(client);
struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
/* prefer platform data */
if (pdata) {
memcpy(data->channel_data, pdata->channel_data,
sizeof(data->channel_data));
return;
}
#ifdef CONFIG_OF
if (!ads1015_get_channels_config_of(client))
return;
#endif
/* fallback on default configuration */
for (k = 0; k < ADS1015_CHANNELS; ++k) {
data->channel_data[k].enabled = true;
data->channel_data[k].pga = ADS1015_DEFAULT_PGA;
data->channel_data[k].data_rate = ADS1015_DEFAULT_DATA_RATE;
}
}
static int ads1015_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ads1015_data *data;
int err;
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 */
ads1015_get_channels_config(client);
for (k = 0; k < ADS1015_CHANNELS; ++k) {
if (!data->channel_data[k].enabled)
continue;
err = device_create_file(&client->dev, &ads1015_in[k].dev_attr);
if (err)
goto exit_remove;
}
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_CHANNELS; ++k)
device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
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,
};
module_i2c_driver(ads1015_driver);
MODULE_AUTHOR("Dirk Eibach <eibach@gdsys.de>");
MODULE_DESCRIPTION("ADS1015 driver");
MODULE_LICENSE("GPL");