diff options
Diffstat (limited to 'drivers/hwmon/ads1015.c')
| -rw-r--r-- | drivers/hwmon/ads1015.c | 337 |
1 files changed, 337 insertions, 0 deletions
diff --git a/drivers/hwmon/ads1015.c b/drivers/hwmon/ads1015.c new file mode 100644 index 00000000000..e9beeda4cbe --- /dev/null +++ b/drivers/hwmon/ads1015.c @@ -0,0 +1,337 @@ +/* + * 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 s32 ads1015_read_reg(struct i2c_client *client, unsigned int reg) +{ + s32 data = i2c_smbus_read_word_data(client, reg); + + return (data < 0) ? data : swab16(data); +} + +static s32 ads1015_write_reg(struct i2c_client *client, unsigned int reg, + u16 val) +{ + return i2c_smbus_write_word_data(client, reg, swab16(val)); +} + +static int ads1015_read_value(struct i2c_client *client, unsigned int channel, + int *value) +{ + u16 config; + s16 conversion; + struct ads1015_data *data = i2c_get_clientdata(client); + 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; + int res; + + mutex_lock(&data->update_lock); + + /* get channel parameters */ + res = ads1015_read_reg(client, ADS1015_CONFIG); + if (res < 0) + goto err_unlock; + config = res; + fullscale = fullscale_table[pga]; + 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 = ads1015_write_reg(client, ADS1015_CONFIG, config); + if (res < 0) + goto err_unlock; + + /* wait until conversion finished */ + msleep(conversion_time_ms); + res = ads1015_read_reg(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 = ads1015_read_reg(client, ADS1015_CONVERSION); + 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\n", in); +} + +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_free; + } + + 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); +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); |