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_device.h>
  35 #include <linux/of.h>
  36
  37 #include <linux/platform_data/ads1015.h>
  38
  39 /* ADS1015 registers */
  40 enum {
  41         ADS1015_CONVERSION = 0,
  42         ADS1015_CONFIG = 1,
  43 };
  44
  45 /* PGA fullscale voltages in mV */
  46 static const unsigned int fullscale_table[8] = {
  47         6144, 4096, 2048, 1024, 512, 256, 256, 256 };
  48
  49 /* Data rates in samples per second */
  50 static const unsigned int data_rate_table_1015[8] = {
  51         128, 250, 490, 920, 1600, 2400, 3300, 3300
  52 };
  53
  54 static const unsigned int data_rate_table_1115[8] = {
  55         8, 16, 32, 64, 128, 250, 475, 860
  56 };
  57
  58 #define ADS1015_DEFAULT_CHANNELS 0xff
  59 #define ADS1015_DEFAULT_PGA 2
  60 #define ADS1015_DEFAULT_DATA_RATE 4
  61
  62 enum ads1015_chips {
  63         ads1015,
  64         ads1115,
  65 };
  66
  67 struct ads1015_data {
  68         struct device *hwmon_dev;
  69         struct mutex update_lock; /* mutex protect updates */
  70         struct ads1015_channel_data channel_data[ADS1015_CHANNELS];
  71         enum ads1015_chips id;
  72 };
  73
  74 static int ads1015_read_adc(struct i2c_client *client, unsigned int channel)
  75 {
  76         u16 config;
  77         struct ads1015_data *data = i2c_get_clientdata(client);
  78         unsigned int pga = data->channel_data[channel].pga;
  79         unsigned int data_rate = data->channel_data[channel].data_rate;
  80         unsigned int conversion_time_ms;
  81         const unsigned int * const rate_table = data->id == ads1115 ?
  82                 data_rate_table_1115 : data_rate_table_1015;
  83         int res;
  84
  85         mutex_lock(&data->update_lock);
  86
  87         /* get channel parameters */
  88         res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
  89         if (res < 0)
  90                 goto err_unlock;
  91         config = res;
  92         conversion_time_ms = DIV_ROUND_UP(1000, rate_table[data_rate]);
  93
  94         /* setup and start single conversion */
  95         config &= 0x001f;
  96         config |= (1 << 15) | (1 << 8);
  97         config |= (channel & 0x0007) << 12;
  98         config |= (pga & 0x0007) << 9;
  99         config |= (data_rate & 0x0007) << 5;
 100
 101         res = i2c_smbus_write_word_swapped(client, ADS1015_CONFIG, config);
 102         if (res < 0)
 103                 goto err_unlock;
 104
 105         /* wait until conversion finished */
 106         msleep(conversion_time_ms);
 107         res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
 108         if (res < 0)
 109                 goto err_unlock;
 110         config = res;
 111         if (!(config & (1 << 15))) {
 112                 /* conversion not finished in time */
 113                 res = -EIO;
 114                 goto err_unlock;
 115         }
 116
 117         res = i2c_smbus_read_word_swapped(client, ADS1015_CONVERSION);
 118
 119 err_unlock:
 120         mutex_unlock(&data->update_lock);
 121         return res;
 122 }
 123
 124 static int ads1015_reg_to_mv(struct i2c_client *client, unsigned int channel,
 125                              s16 reg)
 126 {
 127         struct ads1015_data *data = i2c_get_clientdata(client);
 128         unsigned int pga = data->channel_data[channel].pga;
 129         int fullscale = fullscale_table[pga];
 130         const int mask = data->id == ads1115 ? 0x7fff : 0x7ff0;
 131
 132         return DIV_ROUND_CLOSEST(reg * fullscale, mask);
 133 }
 134
 135 /* sysfs callback function */
 136 static ssize_t show_in(struct device *dev, struct device_attribute *da,
 137         char *buf)
 138 {
 139         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 140         struct i2c_client *client = to_i2c_client(dev);
 141         int res;
 142         int index = attr->index;
 143
 144         res = ads1015_read_adc(client, index);
 145         if (res < 0)
 146                 return res;
 147
 148         return sprintf(buf, "%d\n", ads1015_reg_to_mv(client, index, res));
 149 }
 150
 151 static const struct sensor_device_attribute ads1015_in[] = {
 152         SENSOR_ATTR(in0_input, S_IRUGO, show_in, NULL, 0),
 153         SENSOR_ATTR(in1_input, S_IRUGO, show_in, NULL, 1),
 154         SENSOR_ATTR(in2_input, S_IRUGO, show_in, NULL, 2),
 155         SENSOR_ATTR(in3_input, S_IRUGO, show_in, NULL, 3),
 156         SENSOR_ATTR(in4_input, S_IRUGO, show_in, NULL, 4),
 157         SENSOR_ATTR(in5_input, S_IRUGO, show_in, NULL, 5),
 158         SENSOR_ATTR(in6_input, S_IRUGO, show_in, NULL, 6),
 159         SENSOR_ATTR(in7_input, S_IRUGO, show_in, NULL, 7),
 160 };
 161
 162 /*
 163  * Driver interface
 164  */
 165
 166 static int ads1015_remove(struct i2c_client *client)
 167 {
 168         struct ads1015_data *data = i2c_get_clientdata(client);
 169         int k;
 170
 171         hwmon_device_unregister(data->hwmon_dev);
 172         for (k = 0; k < ADS1015_CHANNELS; ++k)
 173                 device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
 174         return 0;
 175 }
 176
 177 #ifdef CONFIG_OF
 178 static int ads1015_get_channels_config_of(struct i2c_client *client)
 179 {
 180         struct ads1015_data *data = i2c_get_clientdata(client);
 181         struct device_node *node;
 182
 183         if (!client->dev.of_node
 184             || !of_get_next_child(client->dev.of_node, NULL))
 185                 return -EINVAL;
 186
 187         for_each_child_of_node(client->dev.of_node, node) {
 188                 u32 pval;
 189                 unsigned int channel;
 190                 unsigned int pga = ADS1015_DEFAULT_PGA;
 191                 unsigned int data_rate = ADS1015_DEFAULT_DATA_RATE;
 192
 193                 if (of_property_read_u32(node, "reg", &pval)) {
 194                         dev_err(&client->dev, "invalid reg on %s\n",
 195                                 node->full_name);
 196                         continue;
 197                 }
 198
 199                 channel = pval;
 200                 if (channel >= ADS1015_CHANNELS) {
 201                         dev_err(&client->dev,
 202                                 "invalid channel index %d on %s\n",
 203                                 channel, node->full_name);
 204                         continue;
 205                 }
 206
 207                 if (!of_property_read_u32(node, "ti,gain", &pval)) {
 208                         pga = pval;
 209                         if (pga > 6) {
 210                                 dev_err(&client->dev, "invalid gain on %s\n",
 211                                         node->full_name);
 212                                 return -EINVAL;
 213                         }
 214                 }
 215
 216                 if (!of_property_read_u32(node, "ti,datarate", &pval)) {
 217                         data_rate = pval;
 218                         if (data_rate > 7) {
 219                                 dev_err(&client->dev,
 220                                         "invalid data_rate on %s\n",
 221                                         node->full_name);
 222                                 return -EINVAL;
 223                         }
 224                 }
 225
 226                 data->channel_data[channel].enabled = true;
 227                 data->channel_data[channel].pga = pga;
 228                 data->channel_data[channel].data_rate = data_rate;
 229         }
 230
 231         return 0;
 232 }
 233 #endif
 234
 235 static void ads1015_get_channels_config(struct i2c_client *client)
 236 {
 237         unsigned int k;
 238         struct ads1015_data *data = i2c_get_clientdata(client);
 239         struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
 240
 241         /* prefer platform data */
 242         if (pdata) {
 243                 memcpy(data->channel_data, pdata->channel_data,
 244                        sizeof(data->channel_data));
 245                 return;
 246         }
 247
 248 #ifdef CONFIG_OF
 249         if (!ads1015_get_channels_config_of(client))
 250                 return;
 251 #endif
 252
 253         /* fallback on default configuration */
 254         for (k = 0; k < ADS1015_CHANNELS; ++k) {
 255                 data->channel_data[k].enabled = true;
 256                 data->channel_data[k].pga = ADS1015_DEFAULT_PGA;
 257                 data->channel_data[k].data_rate = ADS1015_DEFAULT_DATA_RATE;
 258         }
 259 }
 260
 261 static int ads1015_probe(struct i2c_client *client,
 262                          const struct i2c_device_id *id)
 263 {
 264         struct ads1015_data *data;
 265         int err;
 266         unsigned int k;
 267
 268         data = devm_kzalloc(&client->dev, sizeof(struct ads1015_data),
 269                             GFP_KERNEL);
 270         if (!data)
 271                 return -ENOMEM;
 272
 273         if (client->dev.of_node)
 274                 data->id = (enum ads1015_chips)
 275                         of_device_get_match_data(&client->dev);
 276         else
 277                 data->id = id->driver_data;
 278         i2c_set_clientdata(client, data);
 279         mutex_init(&data->update_lock);
 280
 281         /* build sysfs attribute group */
 282         ads1015_get_channels_config(client);
 283         for (k = 0; k < ADS1015_CHANNELS; ++k) {
 284                 if (!data->channel_data[k].enabled)
 285                         continue;
 286                 err = device_create_file(&client->dev, &ads1015_in[k].dev_attr);
 287                 if (err)
 288                         goto exit_remove;
 289         }
 290
 291         data->hwmon_dev = hwmon_device_register(&client->dev);
 292         if (IS_ERR(data->hwmon_dev)) {
 293                 err = PTR_ERR(data->hwmon_dev);
 294                 goto exit_remove;
 295         }
 296
 297         return 0;
 298
 299 exit_remove:
 300         for (k = 0; k < ADS1015_CHANNELS; ++k)
 301                 device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
 302         return err;
 303 }
 304
 305 static const struct i2c_device_id ads1015_id[] = {
 306         { "ads1015",  ads1015},
 307         { "ads1115",  ads1115},
 308         { }
 309 };
 310 MODULE_DEVICE_TABLE(i2c, ads1015_id);
 311
 312 static const struct of_device_id ads1015_of_match[] = {
 313         {
 314                 .compatible = "ti,ads1015",
 315                 .data = (void *)ads1015
 316         },
 317         {
 318                 .compatible = "ti,ads1115",
 319                 .data = (void *)ads1115
 320         },
 321         { },
 322 };
 323 MODULE_DEVICE_TABLE(of, ads1015_of_match);
 324
 325 static struct i2c_driver ads1015_driver = {
 326         .driver = {
 327                 .name = "ads1015",
 328                 .of_match_table = of_match_ptr(ads1015_of_match),
 329         },
 330         .probe = ads1015_probe,
 331         .remove = ads1015_remove,
 332         .id_table = ads1015_id,
 333 };
 334
 335 module_i2c_driver(ads1015_driver);
 336
 337 MODULE_AUTHOR("Dirk Eibach <eibach@gdsys.de>");
 338 MODULE_DESCRIPTION("ADS1015 driver");
 339 MODULE_LICENSE("GPL");