drivers/hwmon/ads1015.c

   1 /*
   2  * ads1015.c - lm_sensors driver for ads1015 12-bit 4-input ADC
   3  * (C) Copyright 2010
   4  * Dirk Eibach, Guntermann & Drunck GmbH <eibach@gdsys.de>
   5  *
   6  * Based on the ads7828 driver by Steve Hardy.
   7  *
   8  * Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads1015.pdf
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/init.h>
  27 #include <linux/slab.h>
  28 #include <linux/delay.h>
  29 #include <linux/i2c.h>
  30 #include <linux/hwmon.h>
  31 #include <linux/hwmon-sysfs.h>
  32 #include <linux/err.h>
  33 #include <linux/mutex.h>
  34 #include <linux/of.h>
  35
  36 #include <linux/i2c/ads1015.h>
  37
  38 /* ADS1015 registers */
  39 enum {
  40         ADS1015_CONVERSION = 0,
  41         ADS1015_CONFIG = 1,
  42 };
  43
  44 /* PGA fullscale voltages in mV */
  45 static const unsigned int fullscale_table[8] = {
  46         6144, 4096, 2048, 1024, 512, 256, 256, 256 };
  47
  48 /* Data rates in samples per second */
  49 static const unsigned int data_rate_table[8] = {
  50         128, 250, 490, 920, 1600, 2400, 3300, 3300 };
  51
  52 #define ADS1015_DEFAULT_CHANNELS 0xff
  53 #define ADS1015_DEFAULT_PGA 2
  54 #define ADS1015_DEFAULT_DATA_RATE 4
  55
  56 struct ads1015_data {
  57         struct device *hwmon_dev;
  58         struct mutex update_lock; /* mutex protect updates */
  59         struct ads1015_channel_data channel_data[ADS1015_CHANNELS];
  60 };
  61
  62 static int ads1015_read_value(struct i2c_client *client, unsigned int channel,
  63                               int *value)
  64 {
  65         u16 config;
  66         s16 conversion;
  67         struct ads1015_data *data = i2c_get_clientdata(client);
  68         unsigned int pga = data->channel_data[channel].pga;
  69         int fullscale;
  70         unsigned int data_rate = data->channel_data[channel].data_rate;
  71         unsigned int conversion_time_ms;
  72         int res;
  73
  74         mutex_lock(&data->update_lock);
  75
  76         /* get channel parameters */
  77         res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
  78         if (res < 0)
  79                 goto err_unlock;
  80         config = res;
  81         fullscale = fullscale_table[pga];
  82         conversion_time_ms = DIV_ROUND_UP(1000, data_rate_table[data_rate]);
  83
  84         /* setup and start single conversion */
  85         config &= 0x001f;
  86         config |= (1 << 15) | (1 << 8);
  87         config |= (channel & 0x0007) << 12;
  88         config |= (pga & 0x0007) << 9;
  89         config |= (data_rate & 0x0007) << 5;
  90
  91         res = i2c_smbus_write_word_swapped(client, ADS1015_CONFIG, config);
  92         if (res < 0)
  93                 goto err_unlock;
  94
  95         /* wait until conversion finished */
  96         msleep(conversion_time_ms);
  97         res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
  98         if (res < 0)
  99                 goto err_unlock;
 100         config = res;
 101         if (!(config & (1 << 15))) {
 102                 /* conversion not finished in time */
 103                 res = -EIO;
 104                 goto err_unlock;
 105         }
 106
 107         res = i2c_smbus_read_word_swapped(client, ADS1015_CONVERSION);
 108         if (res < 0)
 109                 goto err_unlock;
 110         conversion = res;
 111
 112         mutex_unlock(&data->update_lock);
 113
 114         *value = DIV_ROUND_CLOSEST(conversion * fullscale, 0x7ff0);
 115
 116         return 0;
 117
 118 err_unlock:
 119         mutex_unlock(&data->update_lock);
 120         return res;
 121 }
 122
 123 /* sysfs callback function */
 124 static ssize_t show_in(struct device *dev, struct device_attribute *da,
 125         char *buf)
 126 {
 127         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 128         struct i2c_client *client = to_i2c_client(dev);
 129         int in;
 130         int res;
 131
 132         res = ads1015_read_value(client, attr->index, &in);
 133
 134         return (res < 0) ? res : sprintf(buf, "%d\n", in);
 135 }
 136
 137 static const struct sensor_device_attribute ads1015_in[] = {
 138         SENSOR_ATTR(in0_input, S_IRUGO, show_in, NULL, 0),
 139         SENSOR_ATTR(in1_input, S_IRUGO, show_in, NULL, 1),
 140         SENSOR_ATTR(in2_input, S_IRUGO, show_in, NULL, 2),
 141         SENSOR_ATTR(in3_input, S_IRUGO, show_in, NULL, 3),
 142         SENSOR_ATTR(in4_input, S_IRUGO, show_in, NULL, 4),
 143         SENSOR_ATTR(in5_input, S_IRUGO, show_in, NULL, 5),
 144         SENSOR_ATTR(in6_input, S_IRUGO, show_in, NULL, 6),
 145         SENSOR_ATTR(in7_input, S_IRUGO, show_in, NULL, 7),
 146 };
 147
 148 /*
 149  * Driver interface
 150  */
 151
 152 static int ads1015_remove(struct i2c_client *client)
 153 {
 154         struct ads1015_data *data = i2c_get_clientdata(client);
 155         int k;
 156
 157         hwmon_device_unregister(data->hwmon_dev);
 158         for (k = 0; k < ADS1015_CHANNELS; ++k)
 159                 device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
 160         kfree(data);
 161         return 0;
 162 }
 163
 164 #ifdef CONFIG_OF
 165 static int ads1015_get_channels_config_of(struct i2c_client *client)
 166 {
 167         struct ads1015_data *data = i2c_get_clientdata(client);
 168         struct device_node *node;
 169
 170         if (!client->dev.of_node
 171             || !of_get_next_child(client->dev.of_node, NULL))
 172                 return -EINVAL;
 173
 174         for_each_child_of_node(client->dev.of_node, node) {
 175                 const __be32 *property;
 176                 int len;
 177                 unsigned int channel;
 178                 unsigned int pga = ADS1015_DEFAULT_PGA;
 179                 unsigned int data_rate = ADS1015_DEFAULT_DATA_RATE;
 180
 181                 property = of_get_property(node, "reg", &len);
 182                 if (!property || len != sizeof(int)) {
 183                         dev_err(&client->dev, "invalid reg on %s\n",
 184                                 node->full_name);
 185                         continue;
 186                 }
 187
 188                 channel = be32_to_cpup(property);
 189                 if (channel > ADS1015_CHANNELS) {
 190                         dev_err(&client->dev,
 191                                 "invalid channel index %d on %s\n",
 192                                 channel, node->full_name);
 193                         continue;
 194                 }
 195
 196                 property = of_get_property(node, "ti,gain", &len);
 197                 if (property && len == sizeof(int)) {
 198                         pga = be32_to_cpup(property);
 199                         if (pga > 6) {
 200                                 dev_err(&client->dev,
 201                                         "invalid gain on %s\n",
 202                                         node->full_name);
 203                         }
 204                 }
 205
 206                 property = of_get_property(node, "ti,datarate", &len);
 207                 if (property && len == sizeof(int)) {
 208                         data_rate = be32_to_cpup(property);
 209                         if (data_rate > 7) {
 210                                 dev_err(&client->dev,
 211                                         "invalid data_rate on %s\n",
 212                                         node->full_name);
 213                         }
 214                 }
 215
 216                 data->channel_data[channel].enabled = true;
 217                 data->channel_data[channel].pga = pga;
 218                 data->channel_data[channel].data_rate = data_rate;
 219         }
 220
 221         return 0;
 222 }
 223 #endif
 224
 225 static void ads1015_get_channels_config(struct i2c_client *client)
 226 {
 227         unsigned int k;
 228         struct ads1015_data *data = i2c_get_clientdata(client);
 229         struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
 230
 231         /* prefer platform data */
 232         if (pdata) {
 233                 memcpy(data->channel_data, pdata->channel_data,
 234                        sizeof(data->channel_data));
 235                 return;
 236         }
 237
 238 #ifdef CONFIG_OF
 239         if (!ads1015_get_channels_config_of(client))
 240                 return;
 241 #endif
 242
 243         /* fallback on default configuration */
 244         for (k = 0; k < ADS1015_CHANNELS; ++k) {
 245                 data->channel_data[k].enabled = true;
 246                 data->channel_data[k].pga = ADS1015_DEFAULT_PGA;
 247                 data->channel_data[k].data_rate = ADS1015_DEFAULT_DATA_RATE;
 248         }
 249 }
 250
 251 static int ads1015_probe(struct i2c_client *client,
 252                          const struct i2c_device_id *id)
 253 {
 254         struct ads1015_data *data;
 255         int err;
 256         unsigned int k;
 257
 258         data = kzalloc(sizeof(struct ads1015_data), GFP_KERNEL);
 259         if (!data) {
 260                 err = -ENOMEM;
 261                 goto exit;
 262         }
 263
 264         i2c_set_clientdata(client, data);
 265         mutex_init(&data->update_lock);
 266
 267         /* build sysfs attribute group */
 268         ads1015_get_channels_config(client);
 269         for (k = 0; k < ADS1015_CHANNELS; ++k) {
 270                 if (!data->channel_data[k].enabled)
 271                         continue;
 272                 err = device_create_file(&client->dev, &ads1015_in[k].dev_attr);
 273                 if (err)
 274                         goto exit_remove;
 275         }
 276
 277         data->hwmon_dev = hwmon_device_register(&client->dev);
 278         if (IS_ERR(data->hwmon_dev)) {
 279                 err = PTR_ERR(data->hwmon_dev);
 280                 goto exit_remove;
 281         }
 282
 283         return 0;
 284
 285 exit_remove:
 286         for (k = 0; k < ADS1015_CHANNELS; ++k)
 287                 device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
 288         kfree(data);
 289 exit:
 290         return err;
 291 }
 292
 293 static const struct i2c_device_id ads1015_id[] = {
 294         { "ads1015", 0 },
 295         { }
 296 };
 297 MODULE_DEVICE_TABLE(i2c, ads1015_id);
 298
 299 static struct i2c_driver ads1015_driver = {
 300         .driver = {
 301                 .name = "ads1015",
 302         },
 303         .probe = ads1015_probe,
 304         .remove = ads1015_remove,
 305         .id_table = ads1015_id,
 306 };
 307
 308 module_i2c_driver(ads1015_driver);
 309
 310 MODULE_AUTHOR("Dirk Eibach <eibach@gdsys.de>");
 311 MODULE_DESCRIPTION("ADS1015 driver");
 312 MODULE_LICENSE("GPL");