227 lines
7.0 KiB
C
227 lines
7.0 KiB
C
/*
|
|
* ads7828.c - driver for TI ADS7828 8-channel A/D converter and compatibles
|
|
* (C) 2007 EADS Astrium
|
|
*
|
|
* This driver is based on the lm75 and other lm_sensors/hwmon drivers
|
|
*
|
|
* Written by Steve Hardy <shardy@redhat.com>
|
|
*
|
|
* ADS7830 support, by Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>
|
|
*
|
|
* For further information, see the Documentation/hwmon/ads7828 file.
|
|
*
|
|
* 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/err.h>
|
|
#include <linux/hwmon.h>
|
|
#include <linux/hwmon-sysfs.h>
|
|
#include <linux/i2c.h>
|
|
#include <linux/init.h>
|
|
#include <linux/jiffies.h>
|
|
#include <linux/module.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/platform_data/ads7828.h>
|
|
#include <linux/slab.h>
|
|
|
|
/* The ADS7828 registers */
|
|
#define ADS7828_NCH 8 /* 8 channels supported */
|
|
#define ADS7828_CMD_SD_SE 0x80 /* Single ended inputs */
|
|
#define ADS7828_CMD_PD1 0x04 /* Internal vref OFF && A/D ON */
|
|
#define ADS7828_CMD_PD3 0x0C /* Internal vref ON && A/D ON */
|
|
#define ADS7828_INT_VREF_MV 2500 /* Internal vref is 2.5V, 2500mV */
|
|
#define ADS7828_EXT_VREF_MV_MIN 50 /* External vref min value 0.05V */
|
|
#define ADS7828_EXT_VREF_MV_MAX 5250 /* External vref max value 5.25V */
|
|
|
|
/* List of supported devices */
|
|
enum ads7828_chips { ads7828, ads7830 };
|
|
|
|
/* Client specific data */
|
|
struct ads7828_data {
|
|
struct device *hwmon_dev;
|
|
struct mutex update_lock; /* Mutex protecting updates */
|
|
unsigned long last_updated; /* Last updated time (in jiffies) */
|
|
u16 adc_input[ADS7828_NCH]; /* ADS7828_NCH samples */
|
|
bool valid; /* Validity flag */
|
|
bool diff_input; /* Differential input */
|
|
bool ext_vref; /* External voltage reference */
|
|
unsigned int vref_mv; /* voltage reference value */
|
|
u8 cmd_byte; /* Command byte without channel bits */
|
|
unsigned int lsb_resol; /* Resolution of the ADC sample LSB */
|
|
s32 (*read_channel)(const struct i2c_client *client, u8 command);
|
|
};
|
|
|
|
/* Command byte C2,C1,C0 - see datasheet */
|
|
static inline u8 ads7828_cmd_byte(u8 cmd, int ch)
|
|
{
|
|
return cmd | (((ch >> 1) | (ch & 0x01) << 2) << 4);
|
|
}
|
|
|
|
/* Update data for the device (all 8 channels) */
|
|
static struct ads7828_data *ads7828_update_device(struct device *dev)
|
|
{
|
|
struct i2c_client *client = to_i2c_client(dev);
|
|
struct ads7828_data *data = i2c_get_clientdata(client);
|
|
|
|
mutex_lock(&data->update_lock);
|
|
|
|
if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
|
|
|| !data->valid) {
|
|
unsigned int ch;
|
|
dev_dbg(&client->dev, "Starting ads7828 update\n");
|
|
|
|
for (ch = 0; ch < ADS7828_NCH; ch++) {
|
|
u8 cmd = ads7828_cmd_byte(data->cmd_byte, ch);
|
|
data->adc_input[ch] = data->read_channel(client, cmd);
|
|
}
|
|
data->last_updated = jiffies;
|
|
data->valid = true;
|
|
}
|
|
|
|
mutex_unlock(&data->update_lock);
|
|
|
|
return data;
|
|
}
|
|
|
|
/* sysfs callback function */
|
|
static ssize_t ads7828_show_in(struct device *dev, struct device_attribute *da,
|
|
char *buf)
|
|
{
|
|
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
|
|
struct ads7828_data *data = ads7828_update_device(dev);
|
|
unsigned int value = DIV_ROUND_CLOSEST(data->adc_input[attr->index] *
|
|
data->lsb_resol, 1000);
|
|
|
|
return sprintf(buf, "%d\n", value);
|
|
}
|
|
|
|
static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ads7828_show_in, NULL, 0);
|
|
static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ads7828_show_in, NULL, 1);
|
|
static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ads7828_show_in, NULL, 2);
|
|
static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ads7828_show_in, NULL, 3);
|
|
static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ads7828_show_in, NULL, 4);
|
|
static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO, ads7828_show_in, NULL, 5);
|
|
static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO, ads7828_show_in, NULL, 6);
|
|
static SENSOR_DEVICE_ATTR(in7_input, S_IRUGO, ads7828_show_in, NULL, 7);
|
|
|
|
static struct attribute *ads7828_attributes[] = {
|
|
&sensor_dev_attr_in0_input.dev_attr.attr,
|
|
&sensor_dev_attr_in1_input.dev_attr.attr,
|
|
&sensor_dev_attr_in2_input.dev_attr.attr,
|
|
&sensor_dev_attr_in3_input.dev_attr.attr,
|
|
&sensor_dev_attr_in4_input.dev_attr.attr,
|
|
&sensor_dev_attr_in5_input.dev_attr.attr,
|
|
&sensor_dev_attr_in6_input.dev_attr.attr,
|
|
&sensor_dev_attr_in7_input.dev_attr.attr,
|
|
NULL
|
|
};
|
|
|
|
static const struct attribute_group ads7828_group = {
|
|
.attrs = ads7828_attributes,
|
|
};
|
|
|
|
static int ads7828_remove(struct i2c_client *client)
|
|
{
|
|
struct ads7828_data *data = i2c_get_clientdata(client);
|
|
|
|
hwmon_device_unregister(data->hwmon_dev);
|
|
sysfs_remove_group(&client->dev.kobj, &ads7828_group);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int ads7828_probe(struct i2c_client *client,
|
|
const struct i2c_device_id *id)
|
|
{
|
|
struct ads7828_platform_data *pdata = dev_get_platdata(&client->dev);
|
|
struct ads7828_data *data;
|
|
int err;
|
|
|
|
data = devm_kzalloc(&client->dev, sizeof(struct ads7828_data),
|
|
GFP_KERNEL);
|
|
if (!data)
|
|
return -ENOMEM;
|
|
|
|
if (pdata) {
|
|
data->diff_input = pdata->diff_input;
|
|
data->ext_vref = pdata->ext_vref;
|
|
if (data->ext_vref)
|
|
data->vref_mv = pdata->vref_mv;
|
|
}
|
|
|
|
/* Bound Vref with min/max values if it was provided */
|
|
if (data->vref_mv)
|
|
data->vref_mv = clamp_val(data->vref_mv,
|
|
ADS7828_EXT_VREF_MV_MIN,
|
|
ADS7828_EXT_VREF_MV_MAX);
|
|
else
|
|
data->vref_mv = ADS7828_INT_VREF_MV;
|
|
|
|
/* ADS7828 uses 12-bit samples, while ADS7830 is 8-bit */
|
|
if (id->driver_data == ads7828) {
|
|
data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 4096);
|
|
data->read_channel = i2c_smbus_read_word_swapped;
|
|
} else {
|
|
data->lsb_resol = DIV_ROUND_CLOSEST(data->vref_mv * 1000, 256);
|
|
data->read_channel = i2c_smbus_read_byte_data;
|
|
}
|
|
|
|
data->cmd_byte = data->ext_vref ? ADS7828_CMD_PD1 : ADS7828_CMD_PD3;
|
|
if (!data->diff_input)
|
|
data->cmd_byte |= ADS7828_CMD_SD_SE;
|
|
|
|
i2c_set_clientdata(client, data);
|
|
mutex_init(&data->update_lock);
|
|
|
|
err = sysfs_create_group(&client->dev.kobj, &ads7828_group);
|
|
if (err)
|
|
return err;
|
|
|
|
data->hwmon_dev = hwmon_device_register(&client->dev);
|
|
if (IS_ERR(data->hwmon_dev)) {
|
|
err = PTR_ERR(data->hwmon_dev);
|
|
goto error;
|
|
}
|
|
|
|
return 0;
|
|
|
|
error:
|
|
sysfs_remove_group(&client->dev.kobj, &ads7828_group);
|
|
return err;
|
|
}
|
|
|
|
static const struct i2c_device_id ads7828_device_ids[] = {
|
|
{ "ads7828", ads7828 },
|
|
{ "ads7830", ads7830 },
|
|
{ }
|
|
};
|
|
MODULE_DEVICE_TABLE(i2c, ads7828_device_ids);
|
|
|
|
static struct i2c_driver ads7828_driver = {
|
|
.driver = {
|
|
.name = "ads7828",
|
|
},
|
|
|
|
.id_table = ads7828_device_ids,
|
|
.probe = ads7828_probe,
|
|
.remove = ads7828_remove,
|
|
};
|
|
|
|
module_i2c_driver(ads7828_driver);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Steve Hardy <shardy@redhat.com>");
|
|
MODULE_DESCRIPTION("Driver for TI ADS7828 A/D converter and compatibles");
|