drivers/iio/adc/ti-adc081c.c

   1 /*
   2  * TI ADC081C/ADC101C/ADC121C 8/10/12-bit ADC driver
   3  *
   4  * Copyright (C) 2012 Avionic Design GmbH
   5  * Copyright (C) 2016 Intel
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * Datasheets:
  12  *      http://www.ti.com/lit/ds/symlink/adc081c021.pdf
  13  *      http://www.ti.com/lit/ds/symlink/adc101c021.pdf
  14  *      http://www.ti.com/lit/ds/symlink/adc121c021.pdf
  15  *
  16  * The devices have a very similar interface and differ mostly in the number of
  17  * bits handled. For the 8-bit and 10-bit models the least-significant 4 or 2
  18  * bits of value registers are reserved.
  19  */
  20
  21 #include <linux/err.h>
  22 #include <linux/i2c.h>
  23 #include <linux/module.h>
  24 #include <linux/of.h>
  25 #include <linux/acpi.h>
  26
  27 #include <linux/iio/iio.h>
  28 #include <linux/iio/buffer.h>
  29 #include <linux/iio/trigger_consumer.h>
  30 #include <linux/iio/triggered_buffer.h>
  31 #include <linux/regulator/consumer.h>
  32
  33 struct adc081c {
  34         struct i2c_client *i2c;
  35         struct regulator *ref;
  36
  37         /* 8, 10 or 12 */
  38         int bits;
  39
  40         /* Ensure natural alignment of buffer elements */
  41         struct {
  42                 u16 channel;
  43                 s64 ts __aligned(8);
  44         } scan;
  45 };
  46
  47 #define REG_CONV_RES 0x00
  48
  49 static int adc081c_read_raw(struct iio_dev *iio,
  50                             struct iio_chan_spec const *channel, int *value,
  51                             int *shift, long mask)
  52 {
  53         struct adc081c *adc = iio_priv(iio);
  54         int err;
  55
  56         switch (mask) {
  57         case IIO_CHAN_INFO_RAW:
  58                 err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
  59                 if (err < 0)
  60                         return err;
  61
  62                 *value = (err & 0xFFF) >> (12 - adc->bits);
  63                 return IIO_VAL_INT;
  64
  65         case IIO_CHAN_INFO_SCALE:
  66                 err = regulator_get_voltage(adc->ref);
  67                 if (err < 0)
  68                         return err;
  69
  70                 *value = err / 1000;
  71                 *shift = adc->bits;
  72
  73                 return IIO_VAL_FRACTIONAL_LOG2;
  74
  75         default:
  76                 break;
  77         }
  78
  79         return -EINVAL;
  80 }
  81
  82 #define ADCxx1C_CHAN(_bits) {                                   \
  83         .type = IIO_VOLTAGE,                                    \
  84         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  85         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  86         .scan_type = {                                          \
  87                 .sign = 'u',                                    \
  88                 .realbits = (_bits),                            \
  89                 .storagebits = 16,                              \
  90                 .shift = 12 - (_bits),                          \
  91                 .endianness = IIO_CPU,                          \
  92         },                                                      \
  93 }
  94
  95 #define DEFINE_ADCxx1C_CHANNELS(_name, _bits)                           \
  96         static const struct iio_chan_spec _name ## _channels[] = {      \
  97                 ADCxx1C_CHAN((_bits)),                                  \
  98                 IIO_CHAN_SOFT_TIMESTAMP(1),                             \
  99         };                                                              \
 100
 101 #define ADC081C_NUM_CHANNELS 2
 102
 103 struct adcxx1c_model {
 104         const struct iio_chan_spec* channels;
 105         int bits;
 106 };
 107
 108 #define ADCxx1C_MODEL(_name, _bits)                                     \
 109         {                                                               \
 110                 .channels = _name ## _channels,                         \
 111                 .bits = (_bits),                                        \
 112         }
 113
 114 DEFINE_ADCxx1C_CHANNELS(adc081c,  8);
 115 DEFINE_ADCxx1C_CHANNELS(adc101c, 10);
 116 DEFINE_ADCxx1C_CHANNELS(adc121c, 12);
 117
 118 /* Model ids are indexes in _models array */
 119 enum adcxx1c_model_id {
 120         ADC081C = 0,
 121         ADC101C = 1,
 122         ADC121C = 2,
 123 };
 124
 125 static struct adcxx1c_model adcxx1c_models[] = {
 126         ADCxx1C_MODEL(adc081c,  8),
 127         ADCxx1C_MODEL(adc101c, 10),
 128         ADCxx1C_MODEL(adc121c, 12),
 129 };
 130
 131 static const struct iio_info adc081c_info = {
 132         .read_raw = adc081c_read_raw,
 133 };
 134
 135 static irqreturn_t adc081c_trigger_handler(int irq, void *p)
 136 {
 137         struct iio_poll_func *pf = p;
 138         struct iio_dev *indio_dev = pf->indio_dev;
 139         struct adc081c *data = iio_priv(indio_dev);
 140         int ret;
 141
 142         ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES);
 143         if (ret < 0)
 144                 goto out;
 145         data->scan.channel = ret;
 146         iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 147                                            iio_get_time_ns(indio_dev));
 148 out:
 149         iio_trigger_notify_done(indio_dev->trig);
 150         return IRQ_HANDLED;
 151 }
 152
 153 static int adc081c_probe(struct i2c_client *client,
 154                          const struct i2c_device_id *id)
 155 {
 156         struct iio_dev *iio;
 157         struct adc081c *adc;
 158         struct adcxx1c_model *model;
 159         int err;
 160
 161         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 162                 return -EOPNOTSUPP;
 163
 164         if (ACPI_COMPANION(&client->dev)) {
 165                 const struct acpi_device_id *ad_id;
 166
 167                 ad_id = acpi_match_device(client->dev.driver->acpi_match_table,
 168                                           &client->dev);
 169                 if (!ad_id)
 170                         return -ENODEV;
 171                 model = &adcxx1c_models[ad_id->driver_data];
 172         } else {
 173                 model = &adcxx1c_models[id->driver_data];
 174         }
 175
 176         iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
 177         if (!iio)
 178                 return -ENOMEM;
 179
 180         adc = iio_priv(iio);
 181         adc->i2c = client;
 182         adc->bits = model->bits;
 183
 184         adc->ref = devm_regulator_get(&client->dev, "vref");
 185         if (IS_ERR(adc->ref))
 186                 return PTR_ERR(adc->ref);
 187
 188         err = regulator_enable(adc->ref);
 189         if (err < 0)
 190                 return err;
 191
 192         iio->dev.parent = &client->dev;
 193         iio->dev.of_node = client->dev.of_node;
 194         iio->name = dev_name(&client->dev);
 195         iio->modes = INDIO_DIRECT_MODE;
 196         iio->info = &adc081c_info;
 197
 198         iio->channels = model->channels;
 199         iio->num_channels = ADC081C_NUM_CHANNELS;
 200
 201         err = iio_triggered_buffer_setup(iio, NULL, adc081c_trigger_handler, NULL);
 202         if (err < 0) {
 203                 dev_err(&client->dev, "iio triggered buffer setup failed\n");
 204                 goto err_regulator_disable;
 205         }
 206
 207         err = iio_device_register(iio);
 208         if (err < 0)
 209                 goto err_buffer_cleanup;
 210
 211         i2c_set_clientdata(client, iio);
 212
 213         return 0;
 214
 215 err_buffer_cleanup:
 216         iio_triggered_buffer_cleanup(iio);
 217 err_regulator_disable:
 218         regulator_disable(adc->ref);
 219
 220         return err;
 221 }
 222
 223 static int adc081c_remove(struct i2c_client *client)
 224 {
 225         struct iio_dev *iio = i2c_get_clientdata(client);
 226         struct adc081c *adc = iio_priv(iio);
 227
 228         iio_device_unregister(iio);
 229         iio_triggered_buffer_cleanup(iio);
 230         regulator_disable(adc->ref);
 231
 232         return 0;
 233 }
 234
 235 static const struct i2c_device_id adc081c_id[] = {
 236         { "adc081c", ADC081C },
 237         { "adc101c", ADC101C },
 238         { "adc121c", ADC121C },
 239         { }
 240 };
 241 MODULE_DEVICE_TABLE(i2c, adc081c_id);
 242
 243 #ifdef CONFIG_OF
 244 static const struct of_device_id adc081c_of_match[] = {
 245         { .compatible = "ti,adc081c" },
 246         { .compatible = "ti,adc101c" },
 247         { .compatible = "ti,adc121c" },
 248         { }
 249 };
 250 MODULE_DEVICE_TABLE(of, adc081c_of_match);
 251 #endif
 252
 253 #ifdef CONFIG_ACPI
 254 static const struct acpi_device_id adc081c_acpi_match[] = {
 255         { "ADC081C", ADC081C },
 256         { "ADC101C", ADC101C },
 257         { "ADC121C", ADC121C },
 258         { }
 259 };
 260 MODULE_DEVICE_TABLE(acpi, adc081c_acpi_match);
 261 #endif
 262
 263 static struct i2c_driver adc081c_driver = {
 264         .driver = {
 265                 .name = "adc081c",
 266                 .of_match_table = of_match_ptr(adc081c_of_match),
 267                 .acpi_match_table = ACPI_PTR(adc081c_acpi_match),
 268         },
 269         .probe = adc081c_probe,
 270         .remove = adc081c_remove,
 271         .id_table = adc081c_id,
 272 };
 273 module_i2c_driver(adc081c_driver);
 274
 275 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
 276 MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver");
 277 MODULE_LICENSE("GPL v2");