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         .driver_module = THIS_MODULE,
 128 };
 129
 130 static irqreturn_t adc081c_trigger_handler(int irq, void *p)
 131 {
 132         struct iio_poll_func *pf = p;
 133         struct iio_dev *indio_dev = pf->indio_dev;
 134         struct adc081c *data = iio_priv(indio_dev);
 135         u16 buf[8]; /* 2 bytes data + 6 bytes padding + 8 bytes timestamp */
 136         int ret;
 137
 138         ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES);
 139         if (ret < 0)
 140                 goto out;
 141         buf[0] = ret;
 142         iio_push_to_buffers_with_timestamp(indio_dev, buf,
 143                                            iio_get_time_ns(indio_dev));
 144 out:
 145         iio_trigger_notify_done(indio_dev->trig);
 146         return IRQ_HANDLED;
 147 }
 148
 149 static int adc081c_probe(struct i2c_client *client,
 150                          const struct i2c_device_id *id)
 151 {
 152         struct iio_dev *iio;
 153         struct adc081c *adc;
 154         struct adcxx1c_model *model;
 155         int err;
 156
 157         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 158                 return -EOPNOTSUPP;
 159
 160         if (ACPI_COMPANION(&client->dev)) {
 161                 const struct acpi_device_id *ad_id;
 162
 163                 ad_id = acpi_match_device(client->dev.driver->acpi_match_table,
 164                                           &client->dev);
 165                 if (!ad_id)
 166                         return -ENODEV;
 167                 model = &adcxx1c_models[ad_id->driver_data];
 168         } else {
 169                 model = &adcxx1c_models[id->driver_data];
 170         }
 171
 172         iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
 173         if (!iio)
 174                 return -ENOMEM;
 175
 176         adc = iio_priv(iio);
 177         adc->i2c = client;
 178         adc->bits = model->bits;
 179
 180         adc->ref = devm_regulator_get(&client->dev, "vref");
 181         if (IS_ERR(adc->ref))
 182                 return PTR_ERR(adc->ref);
 183
 184         err = regulator_enable(adc->ref);
 185         if (err < 0)
 186                 return err;
 187
 188         iio->dev.parent = &client->dev;
 189         iio->dev.of_node = client->dev.of_node;
 190         iio->name = dev_name(&client->dev);
 191         iio->modes = INDIO_DIRECT_MODE;
 192         iio->info = &adc081c_info;
 193
 194         iio->channels = model->channels;
 195         iio->num_channels = ADC081C_NUM_CHANNELS;
 196
 197         err = iio_triggered_buffer_setup(iio, NULL, adc081c_trigger_handler, NULL);
 198         if (err < 0) {
 199                 dev_err(&client->dev, "iio triggered buffer setup failed\n");
 200                 goto err_regulator_disable;
 201         }
 202
 203         err = iio_device_register(iio);
 204         if (err < 0)
 205                 goto err_buffer_cleanup;
 206
 207         i2c_set_clientdata(client, iio);
 208
 209         return 0;
 210
 211 err_buffer_cleanup:
 212         iio_triggered_buffer_cleanup(iio);
 213 err_regulator_disable:
 214         regulator_disable(adc->ref);
 215
 216         return err;
 217 }
 218
 219 static int adc081c_remove(struct i2c_client *client)
 220 {
 221         struct iio_dev *iio = i2c_get_clientdata(client);
 222         struct adc081c *adc = iio_priv(iio);
 223
 224         iio_device_unregister(iio);
 225         iio_triggered_buffer_cleanup(iio);
 226         regulator_disable(adc->ref);
 227
 228         return 0;
 229 }
 230
 231 static const struct i2c_device_id adc081c_id[] = {
 232         { "adc081c", ADC081C },
 233         { "adc101c", ADC101C },
 234         { "adc121c", ADC121C },
 235         { }
 236 };
 237 MODULE_DEVICE_TABLE(i2c, adc081c_id);
 238
 239 #ifdef CONFIG_OF
 240 static const struct of_device_id adc081c_of_match[] = {
 241         { .compatible = "ti,adc081c" },
 242         { .compatible = "ti,adc101c" },
 243         { .compatible = "ti,adc121c" },
 244         { }
 245 };
 246 MODULE_DEVICE_TABLE(of, adc081c_of_match);
 247 #endif
 248
 249 #ifdef CONFIG_ACPI
 250 static const struct acpi_device_id adc081c_acpi_match[] = {
 251         { "ADC081C", ADC081C },
 252         { "ADC101C", ADC101C },
 253         { "ADC121C", ADC121C },
 254         { }
 255 };
 256 MODULE_DEVICE_TABLE(acpi, adc081c_acpi_match);
 257 #endif
 258
 259 static struct i2c_driver adc081c_driver = {
 260         .driver = {
 261                 .name = "adc081c",
 262                 .of_match_table = of_match_ptr(adc081c_of_match),
 263                 .acpi_match_table = ACPI_PTR(adc081c_acpi_match),
 264         },
 265         .probe = adc081c_probe,
 266         .remove = adc081c_remove,
 267         .id_table = adc081c_id,
 268 };
 269 module_i2c_driver(adc081c_driver);
 270
 271 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
 272 MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver");
 273 MODULE_LICENSE("GPL v2");