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
  41 #define REG_CONV_RES 0x00
  42
  43 static int adc081c_read_raw(struct iio_dev *iio,
  44                             struct iio_chan_spec const *channel, int *value,
  45                             int *shift, long mask)
  46 {
  47         struct adc081c *adc = iio_priv(iio);
  48         int err;
  49
  50         switch (mask) {
  51         case IIO_CHAN_INFO_RAW:
  52                 err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
  53                 if (err < 0)
  54                         return err;
  55
  56                 *value = (err & 0xFFF) >> (12 - adc->bits);
  57                 return IIO_VAL_INT;
  58
  59         case IIO_CHAN_INFO_SCALE:
  60                 err = regulator_get_voltage(adc->ref);
  61                 if (err < 0)
  62                         return err;
  63
  64                 *value = err / 1000;
  65                 *shift = adc->bits;
  66
  67                 return IIO_VAL_FRACTIONAL_LOG2;
  68
  69         default:
  70                 break;
  71         }
  72
  73         return -EINVAL;
  74 }
  75
  76 #define ADCxx1C_CHAN(_bits) {                                   \
  77         .type = IIO_VOLTAGE,                                    \
  78         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  79         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  80         .scan_type = {                                          \
  81                 .sign = 'u',                                    \
  82                 .realbits = (_bits),                            \
  83                 .storagebits = 16,                              \
  84                 .shift = 12 - (_bits),                          \
  85                 .endianness = IIO_CPU,                          \
  86         },                                                      \
  87 }
  88
  89 #define DEFINE_ADCxx1C_CHANNELS(_name, _bits)                           \
  90         static const struct iio_chan_spec _name ## _channels[] = {      \
  91                 ADCxx1C_CHAN((_bits)),                                  \
  92                 IIO_CHAN_SOFT_TIMESTAMP(1),                             \
  93         };                                                              \
  94
  95 #define ADC081C_NUM_CHANNELS 2
  96
  97 struct adcxx1c_model {
  98         const struct iio_chan_spec* channels;
  99         int bits;
 100 };
 101
 102 #define ADCxx1C_MODEL(_name, _bits)                                     \
 103         {                                                               \
 104                 .channels = _name ## _channels,                         \
 105                 .bits = (_bits),                                        \
 106         }
 107
 108 DEFINE_ADCxx1C_CHANNELS(adc081c,  8);
 109 DEFINE_ADCxx1C_CHANNELS(adc101c, 10);
 110 DEFINE_ADCxx1C_CHANNELS(adc121c, 12);
 111
 112 /* Model ids are indexes in _models array */
 113 enum adcxx1c_model_id {
 114         ADC081C = 0,
 115         ADC101C = 1,
 116         ADC121C = 2,
 117 };
 118
 119 static struct adcxx1c_model adcxx1c_models[] = {
 120         ADCxx1C_MODEL(adc081c,  8),
 121         ADCxx1C_MODEL(adc101c, 10),
 122         ADCxx1C_MODEL(adc121c, 12),
 123 };
 124
 125 static const struct iio_info adc081c_info = {
 126         .read_raw = adc081c_read_raw,
 127 };
 128
 129 static irqreturn_t adc081c_trigger_handler(int irq, void *p)
 130 {
 131         struct iio_poll_func *pf = p;
 132         struct iio_dev *indio_dev = pf->indio_dev;
 133         struct adc081c *data = iio_priv(indio_dev);
 134         u16 buf[8]; /* 2 bytes data + 6 bytes padding + 8 bytes timestamp */
 135         int ret;
 136
 137         ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES);
 138         if (ret < 0)
 139                 goto out;
 140         buf[0] = ret;
 141         iio_push_to_buffers_with_timestamp(indio_dev, buf,
 142                                            iio_get_time_ns(indio_dev));
 143 out:
 144         iio_trigger_notify_done(indio_dev->trig);
 145         return IRQ_HANDLED;
 146 }
 147
 148 static int adc081c_probe(struct i2c_client *client,
 149                          const struct i2c_device_id *id)
 150 {
 151         struct iio_dev *iio;
 152         struct adc081c *adc;
 153         struct adcxx1c_model *model;
 154         int err;
 155
 156         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 157                 return -EOPNOTSUPP;
 158
 159         if (ACPI_COMPANION(&client->dev)) {
 160                 const struct acpi_device_id *ad_id;
 161
 162                 ad_id = acpi_match_device(client->dev.driver->acpi_match_table,
 163                                           &client->dev);
 164                 if (!ad_id)
 165                         return -ENODEV;
 166                 model = &adcxx1c_models[ad_id->driver_data];
 167         } else {
 168                 model = &adcxx1c_models[id->driver_data];
 169         }
 170
 171         iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
 172         if (!iio)
 173                 return -ENOMEM;
 174
 175         adc = iio_priv(iio);
 176         adc->i2c = client;
 177         adc->bits = model->bits;
 178
 179         adc->ref = devm_regulator_get(&client->dev, "vref");
 180         if (IS_ERR(adc->ref))
 181                 return PTR_ERR(adc->ref);
 182
 183         err = regulator_enable(adc->ref);
 184         if (err < 0)
 185                 return err;
 186
 187         iio->dev.parent = &client->dev;
 188         iio->dev.of_node = client->dev.of_node;
 189         iio->name = dev_name(&client->dev);
 190         iio->modes = INDIO_DIRECT_MODE;
 191         iio->info = &adc081c_info;
 192
 193         iio->channels = model->channels;
 194         iio->num_channels = ADC081C_NUM_CHANNELS;
 195
 196         err = iio_triggered_buffer_setup(iio, NULL, adc081c_trigger_handler, NULL);
 197         if (err < 0) {
 198                 dev_err(&client->dev, "iio triggered buffer setup failed\n");
 199                 goto err_regulator_disable;
 200         }
 201
 202         err = iio_device_register(iio);
 203         if (err < 0)
 204                 goto err_buffer_cleanup;
 205
 206         i2c_set_clientdata(client, iio);
 207
 208         return 0;
 209
 210 err_buffer_cleanup:
 211         iio_triggered_buffer_cleanup(iio);
 212 err_regulator_disable:
 213         regulator_disable(adc->ref);
 214
 215         return err;
 216 }
 217
 218 static int adc081c_remove(struct i2c_client *client)
 219 {
 220         struct iio_dev *iio = i2c_get_clientdata(client);
 221         struct adc081c *adc = iio_priv(iio);
 222
 223         iio_device_unregister(iio);
 224         iio_triggered_buffer_cleanup(iio);
 225         regulator_disable(adc->ref);
 226
 227         return 0;
 228 }
 229
 230 static const struct i2c_device_id adc081c_id[] = {
 231         { "adc081c", ADC081C },
 232         { "adc101c", ADC101C },
 233         { "adc121c", ADC121C },
 234         { }
 235 };
 236 MODULE_DEVICE_TABLE(i2c, adc081c_id);
 237
 238 #ifdef CONFIG_OF
 239 static const struct of_device_id adc081c_of_match[] = {
 240         { .compatible = "ti,adc081c" },
 241         { .compatible = "ti,adc101c" },
 242         { .compatible = "ti,adc121c" },
 243         { }
 244 };
 245 MODULE_DEVICE_TABLE(of, adc081c_of_match);
 246 #endif
 247
 248 #ifdef CONFIG_ACPI
 249 static const struct acpi_device_id adc081c_acpi_match[] = {
 250         { "ADC081C", ADC081C },
 251         { "ADC101C", ADC101C },
 252         { "ADC121C", ADC121C },
 253         { }
 254 };
 255 MODULE_DEVICE_TABLE(acpi, adc081c_acpi_match);
 256 #endif
 257
 258 static struct i2c_driver adc081c_driver = {
 259         .driver = {
 260                 .name = "adc081c",
 261                 .of_match_table = of_match_ptr(adc081c_of_match),
 262                 .acpi_match_table = ACPI_PTR(adc081c_acpi_match),
 263         },
 264         .probe = adc081c_probe,
 265         .remove = adc081c_remove,
 266         .id_table = adc081c_id,
 267 };
 268 module_i2c_driver(adc081c_driver);
 269
 270 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
 271 MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver");
 272 MODULE_LICENSE("GPL v2");