320 lines
8.2 KiB
C
320 lines
8.2 KiB
C
/*
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* ads1015.c - lm_sensors driver for ads1015 12-bit 4-input ADC
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* (C) Copyright 2010
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* Dirk Eibach, Guntermann & Drunck GmbH <eibach@gdsys.de>
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*
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* Based on the ads7828 driver by Steve Hardy.
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*
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* Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads1015.pdf
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/delay.h>
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#include <linux/i2c.h>
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#include <linux/hwmon.h>
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#include <linux/hwmon-sysfs.h>
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#include <linux/err.h>
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#include <linux/mutex.h>
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#include <linux/of.h>
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#include <linux/i2c/ads1015.h>
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/* ADS1015 registers */
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enum {
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ADS1015_CONVERSION = 0,
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ADS1015_CONFIG = 1,
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};
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/* PGA fullscale voltages in mV */
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static const unsigned int fullscale_table[8] = {
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6144, 4096, 2048, 1024, 512, 256, 256, 256 };
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/* Data rates in samples per second */
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static const unsigned int data_rate_table_1015[8] = {
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128, 250, 490, 920, 1600, 2400, 3300, 3300
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};
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static const unsigned int data_rate_table_1115[8] = {
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8, 16, 32, 64, 128, 250, 475, 860
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};
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#define ADS1015_DEFAULT_CHANNELS 0xff
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#define ADS1015_DEFAULT_PGA 2
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#define ADS1015_DEFAULT_DATA_RATE 4
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enum ads1015_chips {
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ads1015,
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ads1115,
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};
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struct ads1015_data {
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struct device *hwmon_dev;
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struct mutex update_lock; /* mutex protect updates */
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struct ads1015_channel_data channel_data[ADS1015_CHANNELS];
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enum ads1015_chips id;
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};
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static int ads1015_read_adc(struct i2c_client *client, unsigned int channel)
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{
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u16 config;
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struct ads1015_data *data = i2c_get_clientdata(client);
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unsigned int pga = data->channel_data[channel].pga;
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unsigned int data_rate = data->channel_data[channel].data_rate;
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unsigned int conversion_time_ms;
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const unsigned int * const rate_table = data->id == ads1115 ?
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data_rate_table_1115 : data_rate_table_1015;
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int res;
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mutex_lock(&data->update_lock);
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/* get channel parameters */
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res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
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if (res < 0)
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goto err_unlock;
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config = res;
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conversion_time_ms = DIV_ROUND_UP(1000, rate_table[data_rate]);
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/* setup and start single conversion */
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config &= 0x001f;
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config |= (1 << 15) | (1 << 8);
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config |= (channel & 0x0007) << 12;
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config |= (pga & 0x0007) << 9;
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config |= (data_rate & 0x0007) << 5;
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res = i2c_smbus_write_word_swapped(client, ADS1015_CONFIG, config);
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if (res < 0)
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goto err_unlock;
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/* wait until conversion finished */
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msleep(conversion_time_ms);
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res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
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if (res < 0)
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goto err_unlock;
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config = res;
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if (!(config & (1 << 15))) {
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/* conversion not finished in time */
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res = -EIO;
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goto err_unlock;
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}
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res = i2c_smbus_read_word_swapped(client, ADS1015_CONVERSION);
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err_unlock:
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mutex_unlock(&data->update_lock);
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return res;
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}
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static int ads1015_reg_to_mv(struct i2c_client *client, unsigned int channel,
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s16 reg)
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{
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struct ads1015_data *data = i2c_get_clientdata(client);
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unsigned int pga = data->channel_data[channel].pga;
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int fullscale = fullscale_table[pga];
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const unsigned mask = data->id == ads1115 ? 0x7fff : 0x7ff0;
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return DIV_ROUND_CLOSEST(reg * fullscale, mask);
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}
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/* sysfs callback function */
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static ssize_t show_in(struct device *dev, struct device_attribute *da,
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char *buf)
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{
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
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struct i2c_client *client = to_i2c_client(dev);
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int res;
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int index = attr->index;
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res = ads1015_read_adc(client, index);
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if (res < 0)
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return res;
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return sprintf(buf, "%d\n", ads1015_reg_to_mv(client, index, res));
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}
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static const struct sensor_device_attribute ads1015_in[] = {
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SENSOR_ATTR(in0_input, S_IRUGO, show_in, NULL, 0),
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SENSOR_ATTR(in1_input, S_IRUGO, show_in, NULL, 1),
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SENSOR_ATTR(in2_input, S_IRUGO, show_in, NULL, 2),
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SENSOR_ATTR(in3_input, S_IRUGO, show_in, NULL, 3),
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SENSOR_ATTR(in4_input, S_IRUGO, show_in, NULL, 4),
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SENSOR_ATTR(in5_input, S_IRUGO, show_in, NULL, 5),
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SENSOR_ATTR(in6_input, S_IRUGO, show_in, NULL, 6),
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SENSOR_ATTR(in7_input, S_IRUGO, show_in, NULL, 7),
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};
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/*
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* Driver interface
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*/
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static int ads1015_remove(struct i2c_client *client)
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{
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struct ads1015_data *data = i2c_get_clientdata(client);
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int k;
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hwmon_device_unregister(data->hwmon_dev);
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for (k = 0; k < ADS1015_CHANNELS; ++k)
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device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
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return 0;
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}
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#ifdef CONFIG_OF
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static int ads1015_get_channels_config_of(struct i2c_client *client)
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{
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struct ads1015_data *data = i2c_get_clientdata(client);
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struct device_node *node;
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if (!client->dev.of_node
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|| !of_get_next_child(client->dev.of_node, NULL))
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return -EINVAL;
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for_each_child_of_node(client->dev.of_node, node) {
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u32 pval;
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unsigned int channel;
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unsigned int pga = ADS1015_DEFAULT_PGA;
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unsigned int data_rate = ADS1015_DEFAULT_DATA_RATE;
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if (of_property_read_u32(node, "reg", &pval)) {
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dev_err(&client->dev, "invalid reg on %s\n",
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node->full_name);
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continue;
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}
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channel = pval;
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if (channel >= ADS1015_CHANNELS) {
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dev_err(&client->dev,
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"invalid channel index %d on %s\n",
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channel, node->full_name);
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continue;
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}
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if (!of_property_read_u32(node, "ti,gain", &pval)) {
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pga = pval;
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if (pga > 6) {
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dev_err(&client->dev, "invalid gain on %s\n",
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node->full_name);
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return -EINVAL;
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}
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}
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if (!of_property_read_u32(node, "ti,datarate", &pval)) {
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data_rate = pval;
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if (data_rate > 7) {
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dev_err(&client->dev,
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"invalid data_rate on %s\n",
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node->full_name);
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return -EINVAL;
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}
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}
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data->channel_data[channel].enabled = true;
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data->channel_data[channel].pga = pga;
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data->channel_data[channel].data_rate = data_rate;
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}
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return 0;
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}
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#endif
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static void ads1015_get_channels_config(struct i2c_client *client)
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{
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unsigned int k;
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struct ads1015_data *data = i2c_get_clientdata(client);
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struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
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/* prefer platform data */
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if (pdata) {
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memcpy(data->channel_data, pdata->channel_data,
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sizeof(data->channel_data));
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return;
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}
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#ifdef CONFIG_OF
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if (!ads1015_get_channels_config_of(client))
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return;
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#endif
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/* fallback on default configuration */
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for (k = 0; k < ADS1015_CHANNELS; ++k) {
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data->channel_data[k].enabled = true;
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data->channel_data[k].pga = ADS1015_DEFAULT_PGA;
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data->channel_data[k].data_rate = ADS1015_DEFAULT_DATA_RATE;
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}
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}
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static int ads1015_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct ads1015_data *data;
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int err;
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unsigned int k;
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data = devm_kzalloc(&client->dev, sizeof(struct ads1015_data),
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GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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data->id = id->driver_data;
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i2c_set_clientdata(client, data);
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mutex_init(&data->update_lock);
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/* build sysfs attribute group */
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ads1015_get_channels_config(client);
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for (k = 0; k < ADS1015_CHANNELS; ++k) {
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if (!data->channel_data[k].enabled)
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continue;
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err = device_create_file(&client->dev, &ads1015_in[k].dev_attr);
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if (err)
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goto exit_remove;
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}
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data->hwmon_dev = hwmon_device_register(&client->dev);
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if (IS_ERR(data->hwmon_dev)) {
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err = PTR_ERR(data->hwmon_dev);
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goto exit_remove;
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}
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return 0;
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exit_remove:
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for (k = 0; k < ADS1015_CHANNELS; ++k)
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device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
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return err;
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}
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static const struct i2c_device_id ads1015_id[] = {
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{ "ads1015", ads1015},
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{ "ads1115", ads1115},
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{ }
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};
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MODULE_DEVICE_TABLE(i2c, ads1015_id);
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static struct i2c_driver ads1015_driver = {
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.driver = {
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.name = "ads1015",
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},
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.probe = ads1015_probe,
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.remove = ads1015_remove,
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.id_table = ads1015_id,
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};
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module_i2c_driver(ads1015_driver);
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MODULE_AUTHOR("Dirk Eibach <eibach@gdsys.de>");
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MODULE_DESCRIPTION("ADS1015 driver");
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MODULE_LICENSE("GPL");
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