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_1015[8] = {
  50         128, 250, 490, 920, 1600, 2400, 3300, 3300
  51 };
  52
  53 static const unsigned int data_rate_table_1115[8] = {
  54         8, 16, 32, 64, 128, 250, 475, 860
  55 };
  56
  57 #define ADS1015_DEFAULT_CHANNELS 0xff
  58 #define ADS1015_DEFAULT_PGA 2
  59 #define ADS1015_DEFAULT_DATA_RATE 4
  60
  61 enum ads1015_chips {
  62         ads1015,
  63         ads1115,
  64 };
  65
  66 struct ads1015_data {
  67         struct device *hwmon_dev;
  68         struct mutex update_lock; /* mutex protect updates */
  69         struct ads1015_channel_data channel_data[ADS1015_CHANNELS];
  70         enum ads1015_chips id;
  71 };
  72
  73 static int ads1015_read_adc(struct i2c_client *client, unsigned int channel)
  74 {
  75         u16 config;
  76         struct ads1015_data *data = i2c_get_clientdata(client);
  77         unsigned int pga = data->channel_data[channel].pga;
  78         unsigned int data_rate = data->channel_data[channel].data_rate;
  79         unsigned int conversion_time_ms;
  80         const unsigned int * const rate_table = data->id == ads1115 ?
  81                 data_rate_table_1115 : data_rate_table_1015;
  82         int res;
  83
  84         mutex_lock(&data->update_lock);
  85
  86         /* get channel parameters */
  87         res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
  88         if (res < 0)
  89                 goto err_unlock;
  90         config = res;
  91         conversion_time_ms = DIV_ROUND_UP(1000, rate_table[data_rate]);
  92
  93         /* setup and start single conversion */
  94         config &= 0x001f;
  95         config |= (1 << 15) | (1 << 8);
  96         config |= (channel & 0x0007) << 12;
  97         config |= (pga & 0x0007) << 9;
  98         config |= (data_rate & 0x0007) << 5;
  99
 100         res = i2c_smbus_write_word_swapped(client, ADS1015_CONFIG, config);
 101         if (res < 0)
 102                 goto err_unlock;
 103
 104         /* wait until conversion finished */
 105         msleep(conversion_time_ms);
 106         res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
 107         if (res < 0)
 108                 goto err_unlock;
 109         config = res;
 110         if (!(config & (1 << 15))) {
 111                 /* conversion not finished in time */
 112                 res = -EIO;
 113                 goto err_unlock;
 114         }
 115
 116         res = i2c_smbus_read_word_swapped(client, ADS1015_CONVERSION);
 117
 118 err_unlock:
 119         mutex_unlock(&data->update_lock);
 120         return res;
 121 }
 122
 123 static int ads1015_reg_to_mv(struct i2c_client *client, unsigned int channel,
 124                              s16 reg)
 125 {
 126         struct ads1015_data *data = i2c_get_clientdata(client);
 127         unsigned int pga = data->channel_data[channel].pga;
 128         int fullscale = fullscale_table[pga];
 129         const int mask = data->id == ads1115 ? 0x7fff : 0x7ff0;
 130
 131         return DIV_ROUND_CLOSEST(reg * fullscale, mask);
 132 }
 133
 134 /* sysfs callback function */
 135 static ssize_t show_in(struct device *dev, struct device_attribute *da,
 136         char *buf)
 137 {
 138         struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 139         struct i2c_client *client = to_i2c_client(dev);
 140         int res;
 141         int index = attr->index;
 142
 143         res = ads1015_read_adc(client, index);
 144         if (res < 0)
 145                 return res;
 146
 147         return sprintf(buf, "%d\n", ads1015_reg_to_mv(client, index, res));
 148 }
 149
 150 static const struct sensor_device_attribute ads1015_in[] = {
 151         SENSOR_ATTR(in0_input, S_IRUGO, show_in, NULL, 0),
 152         SENSOR_ATTR(in1_input, S_IRUGO, show_in, NULL, 1),
 153         SENSOR_ATTR(in2_input, S_IRUGO, show_in, NULL, 2),
 154         SENSOR_ATTR(in3_input, S_IRUGO, show_in, NULL, 3),
 155         SENSOR_ATTR(in4_input, S_IRUGO, show_in, NULL, 4),
 156         SENSOR_ATTR(in5_input, S_IRUGO, show_in, NULL, 5),
 157         SENSOR_ATTR(in6_input, S_IRUGO, show_in, NULL, 6),
 158         SENSOR_ATTR(in7_input, S_IRUGO, show_in, NULL, 7),
 159 };
 160
 161 /*
 162  * Driver interface
 163  */
 164
 165 static int ads1015_remove(struct i2c_client *client)
 166 {
 167         struct ads1015_data *data = i2c_get_clientdata(client);
 168         int k;
 169
 170         hwmon_device_unregister(data->hwmon_dev);
 171         for (k = 0; k < ADS1015_CHANNELS; ++k)
 172                 device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
 173         return 0;
 174 }
 175
 176 #ifdef CONFIG_OF
 177 static int ads1015_get_channels_config_of(struct i2c_client *client)
 178 {
 179         struct ads1015_data *data = i2c_get_clientdata(client);
 180         struct device_node *node;
 181
 182         if (!client->dev.of_node
 183             || !of_get_next_child(client->dev.of_node, NULL))
 184                 return -EINVAL;
 185
 186         for_each_child_of_node(client->dev.of_node, node) {
 187                 u32 pval;
 188                 unsigned int channel;
 189                 unsigned int pga = ADS1015_DEFAULT_PGA;
 190                 unsigned int data_rate = ADS1015_DEFAULT_DATA_RATE;
 191
 192                 if (of_property_read_u32(node, "reg", &pval)) {
 193                         dev_err(&client->dev, "invalid reg on %s\n",
 194                                 node->full_name);
 195                         continue;
 196                 }
 197
 198                 channel = pval;
 199                 if (channel >= ADS1015_CHANNELS) {
 200                         dev_err(&client->dev,
 201                                 "invalid channel index %d on %s\n",
 202                                 channel, node->full_name);
 203                         continue;
 204                 }
 205
 206                 if (!of_property_read_u32(node, "ti,gain", &pval)) {
 207                         pga = pval;
 208                         if (pga > 6) {
 209                                 dev_err(&client->dev, "invalid gain on %s\n",
 210                                         node->full_name);
 211                                 return -EINVAL;
 212                         }
 213                 }
 214
 215                 if (!of_property_read_u32(node, "ti,datarate", &pval)) {
 216                         data_rate = pval;
 217                         if (data_rate > 7) {
 218                                 dev_err(&client->dev,
 219                                         "invalid data_rate on %s\n",
 220                                         node->full_name);
 221                                 return -EINVAL;
 222                         }
 223                 }
 224
 225                 data->channel_data[channel].enabled = true;
 226                 data->channel_data[channel].pga = pga;
 227                 data->channel_data[channel].data_rate = data_rate;
 228         }
 229
 230         return 0;
 231 }
 232 #endif
 233
 234 static void ads1015_get_channels_config(struct i2c_client *client)
 235 {
 236         unsigned int k;
 237         struct ads1015_data *data = i2c_get_clientdata(client);
 238         struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
 239
 240         /* prefer platform data */
 241         if (pdata) {
 242                 memcpy(data->channel_data, pdata->channel_data,
 243                        sizeof(data->channel_data));
 244                 return;
 245         }
 246
 247 #ifdef CONFIG_OF
 248         if (!ads1015_get_channels_config_of(client))
 249                 return;
 250 #endif
 251
 252         /* fallback on default configuration */
 253         for (k = 0; k < ADS1015_CHANNELS; ++k) {
 254                 data->channel_data[k].enabled = true;
 255                 data->channel_data[k].pga = ADS1015_DEFAULT_PGA;
 256                 data->channel_data[k].data_rate = ADS1015_DEFAULT_DATA_RATE;
 257         }
 258 }
 259
 260 static int ads1015_probe(struct i2c_client *client,
 261                          const struct i2c_device_id *id)
 262 {
 263         struct ads1015_data *data;
 264         int err;
 265         unsigned int k;
 266
 267         data = devm_kzalloc(&client->dev, sizeof(struct ads1015_data),
 268                             GFP_KERNEL);
 269         if (!data)
 270                 return -ENOMEM;
 271         data->id = id->driver_data;
 272         i2c_set_clientdata(client, data);
 273         mutex_init(&data->update_lock);
 274
 275         /* build sysfs attribute group */
 276         ads1015_get_channels_config(client);
 277         for (k = 0; k < ADS1015_CHANNELS; ++k) {
 278                 if (!data->channel_data[k].enabled)
 279                         continue;
 280                 err = device_create_file(&client->dev, &ads1015_in[k].dev_attr);
 281                 if (err)
 282                         goto exit_remove;
 283         }
 284
 285         data->hwmon_dev = hwmon_device_register(&client->dev);
 286         if (IS_ERR(data->hwmon_dev)) {
 287                 err = PTR_ERR(data->hwmon_dev);
 288                 goto exit_remove;
 289         }
 290
 291         return 0;
 292
 293 exit_remove:
 294         for (k = 0; k < ADS1015_CHANNELS; ++k)
 295                 device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
 296         return err;
 297 }
 298
 299 static const struct i2c_device_id ads1015_id[] = {
 300         { "ads1015",  ads1015},
 301         { "ads1115",  ads1115},
 302         { }
 303 };
 304 MODULE_DEVICE_TABLE(i2c, ads1015_id);
 305
 306 static struct i2c_driver ads1015_driver = {
 307         .driver = {
 308                 .name = "ads1015",
 309         },
 310         .probe = ads1015_probe,
 311         .remove = ads1015_remove,
 312         .id_table = ads1015_id,
 313 };
 314
 315 module_i2c_driver(ads1015_driver);
 316
 317 MODULE_AUTHOR("Dirk Eibach <eibach@gdsys.de>");
 318 MODULE_DESCRIPTION("ADS1015 driver");
 319 MODULE_LICENSE("GPL");