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drivers/hwmon/ads1015.c
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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 }; |
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/* Data rates in samples per second */ static const unsigned int data_rate_table[8] = { 128, 250, 490, 920, 1600, 2400, 3300, 3300 }; |
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#define ADS1015_DEFAULT_CHANNELS 0xff |
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#define ADS1015_DEFAULT_PGA 2 #define ADS1015_DEFAULT_DATA_RATE 4 |
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struct ads1015_data { struct device *hwmon_dev; struct mutex update_lock; /* mutex protect updates */ |
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struct ads1015_channel_data channel_data[ADS1015_CHANNELS]; |
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}; |
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static int ads1015_read_value(struct i2c_client *client, unsigned int channel, int *value) { u16 config; s16 conversion; |
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struct ads1015_data *data = i2c_get_clientdata(client); |
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unsigned int pga = data->channel_data[channel].pga; int fullscale; unsigned int data_rate = data->channel_data[channel].data_rate; unsigned int conversion_time_ms; |
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int res; 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) goto err_unlock; config = res; |
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fullscale = fullscale_table[pga]; |
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conversion_time_ms = DIV_ROUND_UP(1000, data_rate_table[data_rate]); |
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/* 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; |
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res = i2c_smbus_write_word_swapped(client, ADS1015_CONFIG, config); |
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if (res < 0) goto err_unlock; |
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/* wait until conversion finished */ msleep(conversion_time_ms); |
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res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG); |
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if (res < 0) goto err_unlock; config = res; if (!(config & (1 << 15))) { /* conversion not finished in time */ |
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res = -EIO; goto err_unlock; } |
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res = i2c_smbus_read_word_swapped(client, ADS1015_CONVERSION); |
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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 ", in); } |
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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), |
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}; /* * Driver interface */ static int ads1015_remove(struct i2c_client *client) { 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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kfree(data); return 0; } |
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#ifdef CONFIG_OF |
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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 ", node->full_name); continue; } channel = be32_to_cpup(property); if (channel > ADS1015_CHANNELS) { dev_err(&client->dev, "invalid channel index %d on %s ", 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 ", 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 ", 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; } |
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#endif |
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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); |
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/* prefer platform data */ |
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if (pdata) { memcpy(data->channel_data, pdata->channel_data, sizeof(data->channel_data)); return; } |
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#ifdef CONFIG_OF |
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if (!ads1015_get_channels_config_of(client)) return; |
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#endif /* fallback on default configuration */ |
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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; } |
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} static int ads1015_probe(struct i2c_client *client, const struct i2c_device_id *id) { struct ads1015_data *data; int err; |
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unsigned int k; |
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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 */ |
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ads1015_get_channels_config(client); for (k = 0; k < ADS1015_CHANNELS; ++k) { 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); if (err) goto exit_free; |
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} |
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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: |
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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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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); |