diff options
Diffstat (limited to 'drivers/hwmon/ads1015.c')
| -rw-r--r-- | drivers/hwmon/ads1015.c | 282 |
1 files changed, 282 insertions, 0 deletions
diff --git a/drivers/hwmon/ads1015.c b/drivers/hwmon/ads1015.c new file mode 100644 index 00000000000..9e1585c3152 --- /dev/null +++ b/drivers/hwmon/ads1015.c @@ -0,0 +1,282 @@ +/* + * 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 }; + +#define ADS1015_CONFIG_CHANNELS 8 +#define ADS1015_DEFAULT_CHANNELS 0xff + +struct ads1015_data { + struct device *hwmon_dev; + struct mutex update_lock; /* mutex protect updates */ + struct attribute *attr_table[ADS1015_CONFIG_CHANNELS + 1]; + struct attribute_group attr_group; +}; + +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; + unsigned int pga; + int fullscale; + unsigned int k; + struct ads1015_data *data = i2c_get_clientdata(client); + int res; + + mutex_lock(&data->update_lock); + + /* get fullscale voltage */ + res = ads1015_read_reg(client, ADS1015_CONFIG); + if (res < 0) + goto err_unlock; + config = res; + pga = (config >> 9) & 0x0007; + fullscale = fullscale_table[pga]; + + /* set channel and start single conversion */ + config &= ~(0x0007 << 12); + config |= (1 << 15) | (1 << 8) | (channel & 0x0007) << 12; + + /* wait until conversion finished */ + res = ads1015_write_reg(client, ADS1015_CONFIG, config); + if (res < 0) + goto err_unlock; + for (k = 0; k < 5; ++k) { + msleep(1); + res = ads1015_read_reg(client, ADS1015_CONFIG); + if (res < 0) + goto err_unlock; + config = res; + if (config & (1 << 15)) + break; + } + if (k == 5) { + 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); +} + +#define in_reg(offset)\ +static SENSOR_DEVICE_ATTR(in##offset##_input, S_IRUGO, show_in,\ + NULL, offset) + +in_reg(0); +in_reg(1); +in_reg(2); +in_reg(3); +in_reg(4); +in_reg(5); +in_reg(6); +in_reg(7); + +static struct attribute *all_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, +}; + +/* + * Driver interface + */ + +static int ads1015_remove(struct i2c_client *client) +{ + struct ads1015_data *data = i2c_get_clientdata(client); + hwmon_device_unregister(data->hwmon_dev); + sysfs_remove_group(&client->dev.kobj, &data->attr_group); + kfree(data); + return 0; +} + +static unsigned int ads1015_get_exported_channels(struct i2c_client *client) +{ + struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev); +#ifdef CONFIG_OF + struct device_node *np = client->dev.of_node; + const __be32 *of_channels; + int of_channels_size; +#endif + + /* prefer platform data */ + if (pdata) + return pdata->exported_channels; + +#ifdef CONFIG_OF + /* fallback on OF */ + of_channels = of_get_property(np, "exported-channels", + &of_channels_size); + if (of_channels && (of_channels_size == sizeof(*of_channels))) + return be32_to_cpup(of_channels); +#endif + + /* fallback on default configuration */ + return ADS1015_DEFAULT_CHANNELS; +} + +static int ads1015_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct ads1015_data *data; + int err; + unsigned int exported_channels; + unsigned int k; + unsigned int n = 0; + + 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 */ + data->attr_group.attrs = data->attr_table; + exported_channels = ads1015_get_exported_channels(client); + for (k = 0; k < ADS1015_CONFIG_CHANNELS; ++k) { + if (!(exported_channels & (1<<k))) + continue; + data->attr_table[n++] = all_attributes[k]; + } + err = sysfs_create_group(&client->dev.kobj, &data->attr_group); + 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: + sysfs_remove_group(&client->dev.kobj, &data->attr_group); +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); |