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
  26 #include <linux/iio/iio.h>
  27 #include <linux/iio/buffer.h>
  28 #include <linux/iio/trigger_consumer.h>
  29 #include <linux/iio/triggered_buffer.h>
  30 #include <linux/regulator/consumer.h>
  31
  32 struct adc081c {
  33         struct i2c_client *i2c;
  34         struct regulator *ref;
  35
  36         /* 8, 10 or 12 */
  37         int bits;
  38 };
  39
  40 #define REG_CONV_RES 0x00
  41
  42 static int adc081c_read_raw(struct iio_dev *iio,
  43                             struct iio_chan_spec const *channel, int *value,
  44                             int *shift, long mask)
  45 {
  46         struct adc081c *adc = iio_priv(iio);
  47         int err;
  48
  49         switch (mask) {
  50         case IIO_CHAN_INFO_RAW:
  51                 err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
  52                 if (err < 0)
  53                         return err;
  54
  55                 *value = (err & 0xFFF) >> (12 - adc->bits);
  56                 return IIO_VAL_INT;
  57
  58         case IIO_CHAN_INFO_SCALE:
  59                 err = regulator_get_voltage(adc->ref);
  60                 if (err < 0)
  61                         return err;
  62
  63                 *value = err / 1000;
  64                 *shift = adc->bits;
  65
  66                 return IIO_VAL_FRACTIONAL_LOG2;
  67
  68         default:
  69                 break;
  70         }
  71
  72         return -EINVAL;
  73 }
  74
  75 #define ADCxx1C_CHAN(_bits) {                                   \
  76         .type = IIO_VOLTAGE,                                    \
  77         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  78         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  79         .scan_type = {                                          \
  80                 .sign = 'u',                                    \
  81                 .realbits = (_bits),                            \
  82                 .storagebits = 16,                              \
  83                 .shift = 12 - (_bits),                          \
  84                 .endianness = IIO_CPU,                          \
  85         },                                                      \
  86 }
  87
  88 #define DEFINE_ADCxx1C_CHANNELS(_name, _bits)                           \
  89         static const struct iio_chan_spec _name ## _channels[] = {      \
  90                 ADCxx1C_CHAN((_bits)),                                  \
  91                 IIO_CHAN_SOFT_TIMESTAMP(1),                             \
  92         };                                                              \
  93
  94 #define ADC081C_NUM_CHANNELS 2
  95
  96 struct adcxx1c_model {
  97         const struct iio_chan_spec* channels;
  98         int bits;
  99 };
 100
 101 #define ADCxx1C_MODEL(_name, _bits)                                     \
 102         {                                                               \
 103                 .channels = _name ## _channels,                         \
 104                 .bits = (_bits),                                        \
 105         }
 106
 107 DEFINE_ADCxx1C_CHANNELS(adc081c,  8);
 108 DEFINE_ADCxx1C_CHANNELS(adc101c, 10);
 109 DEFINE_ADCxx1C_CHANNELS(adc121c, 12);
 110
 111 /* Model ids are indexes in _models array */
 112 enum adcxx1c_model_id {
 113         ADC081C = 0,
 114         ADC101C = 1,
 115         ADC121C = 2,
 116 };
 117
 118 static struct adcxx1c_model adcxx1c_models[] = {
 119         ADCxx1C_MODEL(adc081c,  8),
 120         ADCxx1C_MODEL(adc101c, 10),
 121         ADCxx1C_MODEL(adc121c, 12),
 122 };
 123
 124 static const struct iio_info adc081c_info = {
 125         .read_raw = adc081c_read_raw,
 126         .driver_module = THIS_MODULE,
 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, iio_get_time_ns());
 142 out:
 143         iio_trigger_notify_done(indio_dev->trig);
 144         return IRQ_HANDLED;
 145 }
 146
 147 static int adc081c_probe(struct i2c_client *client,
 148                          const struct i2c_device_id *id)
 149 {
 150         struct iio_dev *iio;
 151         struct adc081c *adc;
 152         struct adcxx1c_model *model = &adcxx1c_models[id->driver_data];
 153         int err;
 154
 155         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 156                 return -EOPNOTSUPP;
 157
 158         iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
 159         if (!iio)
 160                 return -ENOMEM;
 161
 162         adc = iio_priv(iio);
 163         adc->i2c = client;
 164         adc->bits = model->bits;
 165
 166         adc->ref = devm_regulator_get(&client->dev, "vref");
 167         if (IS_ERR(adc->ref))
 168                 return PTR_ERR(adc->ref);
 169
 170         err = regulator_enable(adc->ref);
 171         if (err < 0)
 172                 return err;
 173
 174         iio->dev.parent = &client->dev;
 175         iio->name = dev_name(&client->dev);
 176         iio->modes = INDIO_DIRECT_MODE;
 177         iio->info = &adc081c_info;
 178
 179         iio->channels = model->channels;
 180         iio->num_channels = ADC081C_NUM_CHANNELS;
 181
 182         err = iio_triggered_buffer_setup(iio, NULL, adc081c_trigger_handler, NULL);
 183         if (err < 0) {
 184                 dev_err(&client->dev, "iio triggered buffer setup failed\n");
 185                 goto err_regulator_disable;
 186         }
 187
 188         err = iio_device_register(iio);
 189         if (err < 0)
 190                 goto err_buffer_cleanup;
 191
 192         i2c_set_clientdata(client, iio);
 193
 194         return 0;
 195
 196 err_buffer_cleanup:
 197         iio_triggered_buffer_cleanup(iio);
 198 err_regulator_disable:
 199         regulator_disable(adc->ref);
 200
 201         return err;
 202 }
 203
 204 static int adc081c_remove(struct i2c_client *client)
 205 {
 206         struct iio_dev *iio = i2c_get_clientdata(client);
 207         struct adc081c *adc = iio_priv(iio);
 208
 209         iio_device_unregister(iio);
 210         iio_triggered_buffer_cleanup(iio);
 211         regulator_disable(adc->ref);
 212
 213         return 0;
 214 }
 215
 216 static const struct i2c_device_id adc081c_id[] = {
 217         { "adc081c", ADC081C },
 218         { "adc101c", ADC101C },
 219         { "adc121c", ADC121C },
 220         { }
 221 };
 222 MODULE_DEVICE_TABLE(i2c, adc081c_id);
 223
 224 #ifdef CONFIG_OF
 225 static const struct of_device_id adc081c_of_match[] = {
 226         { .compatible = "ti,adc081c" },
 227         { .compatible = "ti,adc101c" },
 228         { .compatible = "ti,adc121c" },
 229         { }
 230 };
 231 MODULE_DEVICE_TABLE(of, adc081c_of_match);
 232 #endif
 233
 234 static struct i2c_driver adc081c_driver = {
 235         .driver = {
 236                 .name = "adc081c",
 237                 .of_match_table = of_match_ptr(adc081c_of_match),
 238         },
 239         .probe = adc081c_probe,
 240         .remove = adc081c_remove,
 241         .id_table = adc081c_id,
 242 };
 243 module_i2c_driver(adc081c_driver);
 244
 245 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
 246 MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver");
 247 MODULE_LICENSE("GPL v2");