/* * 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); 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 = devm_kzalloc(&client->dev, sizeof(struct ads1015_data), GFP_KERNEL); if (!data) return -ENOMEM; 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); 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");