drivers/iio/adc/ti-adc081c.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * TI ADC081C/ADC101C/ADC121C 8/10/12-bit ADC driver
   4  *
   5  * Copyright (C) 2012 Avionic Design GmbH
   6  * Copyright (C) 2016 Intel
   7  *
   8  * Datasheets:
   9  *      https://www.ti.com/lit/ds/symlink/adc081c021.pdf
  10  *      https://www.ti.com/lit/ds/symlink/adc101c021.pdf
  11  *      https://www.ti.com/lit/ds/symlink/adc121c021.pdf
  12  *
  13  * The devices have a very similar interface and differ mostly in the number of
  14  * bits handled. For the 8-bit and 10-bit models the least-significant 4 or 2
  15  * bits of value registers are reserved.
  16  */
  17
  18 #include <linux/err.h>
  19 #include <linux/i2c.h>
  20 #include <linux/module.h>
  21 #include <linux/mod_devicetable.h>
  22
  23 #include <linux/iio/iio.h>
  24 #include <linux/iio/buffer.h>
  25 #include <linux/iio/trigger_consumer.h>
  26 #include <linux/iio/triggered_buffer.h>
  27 #include <linux/regulator/consumer.h>
  28
  29 struct adc081c {
  30         struct i2c_client *i2c;
  31         struct regulator *ref;
  32
  33         /* 8, 10 or 12 */
  34         int bits;
  35
  36         /* Ensure natural alignment of buffer elements */
  37         struct {
  38                 u16 channel;
  39                 s64 ts __aligned(8);
  40         } scan;
  41 };
  42
  43 #define REG_CONV_RES 0x00
  44
  45 static int adc081c_read_raw(struct iio_dev *iio,
  46                             struct iio_chan_spec const *channel, int *value,
  47                             int *shift, long mask)
  48 {
  49         struct adc081c *adc = iio_priv(iio);
  50         int err;
  51
  52         switch (mask) {
  53         case IIO_CHAN_INFO_RAW:
  54                 err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
  55                 if (err < 0)
  56                         return err;
  57
  58                 *value = (err & 0xFFF) >> (12 - adc->bits);
  59                 return IIO_VAL_INT;
  60
  61         case IIO_CHAN_INFO_SCALE:
  62                 err = regulator_get_voltage(adc->ref);
  63                 if (err < 0)
  64                         return err;
  65
  66                 *value = err / 1000;
  67                 *shift = adc->bits;
  68
  69                 return IIO_VAL_FRACTIONAL_LOG2;
  70
  71         default:
  72                 break;
  73         }
  74
  75         return -EINVAL;
  76 }
  77
  78 #define ADCxx1C_CHAN(_bits) {                                   \
  79         .type = IIO_VOLTAGE,                                    \
  80         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  81         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  82         .scan_type = {                                          \
  83                 .sign = 'u',                                    \
  84                 .realbits = (_bits),                            \
  85                 .storagebits = 16,                              \
  86                 .shift = 12 - (_bits),                          \
  87                 .endianness = IIO_CPU,                          \
  88         },                                                      \
  89 }
  90
  91 #define DEFINE_ADCxx1C_CHANNELS(_name, _bits)                           \
  92         static const struct iio_chan_spec _name ## _channels[] = {      \
  93                 ADCxx1C_CHAN((_bits)),                                  \
  94                 IIO_CHAN_SOFT_TIMESTAMP(1),                             \
  95         };                                                              \
  96
  97 #define ADC081C_NUM_CHANNELS 2
  98
  99 struct adcxx1c_model {
 100         const struct iio_chan_spec* channels;
 101         int bits;
 102 };
 103
 104 #define ADCxx1C_MODEL(_name, _bits)                                     \
 105         {                                                               \
 106                 .channels = _name ## _channels,                         \
 107                 .bits = (_bits),                                        \
 108         }
 109
 110 DEFINE_ADCxx1C_CHANNELS(adc081c,  8);
 111 DEFINE_ADCxx1C_CHANNELS(adc101c, 10);
 112 DEFINE_ADCxx1C_CHANNELS(adc121c, 12);
 113
 114 /* Model ids are indexes in _models array */
 115 enum adcxx1c_model_id {
 116         ADC081C = 0,
 117         ADC101C = 1,
 118         ADC121C = 2,
 119 };
 120
 121 static struct adcxx1c_model adcxx1c_models[] = {
 122         ADCxx1C_MODEL(adc081c,  8),
 123         ADCxx1C_MODEL(adc101c, 10),
 124         ADCxx1C_MODEL(adc121c, 12),
 125 };
 126
 127 static const struct iio_info adc081c_info = {
 128         .read_raw = adc081c_read_raw,
 129 };
 130
 131 static irqreturn_t adc081c_trigger_handler(int irq, void *p)
 132 {
 133         struct iio_poll_func *pf = p;
 134         struct iio_dev *indio_dev = pf->indio_dev;
 135         struct adc081c *data = iio_priv(indio_dev);
 136         int ret;
 137
 138         ret = i2c_smbus_read_word_swapped(data->i2c, REG_CONV_RES);
 139         if (ret < 0)
 140                 goto out;
 141         data->scan.channel = ret;
 142         iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 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 void adc081c_reg_disable(void *reg)
 150 {
 151         regulator_disable(reg);
 152 }
 153
 154 static int adc081c_probe(struct i2c_client *client,
 155                          const struct i2c_device_id *id)
 156 {
 157         struct iio_dev *iio;
 158         struct adc081c *adc;
 159         struct adcxx1c_model *model;
 160         int err;
 161
 162         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
 163                 return -EOPNOTSUPP;
 164
 165         model = &adcxx1c_models[id->driver_data];
 166
 167         iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
 168         if (!iio)
 169                 return -ENOMEM;
 170
 171         adc = iio_priv(iio);
 172         adc->i2c = client;
 173         adc->bits = model->bits;
 174
 175         adc->ref = devm_regulator_get(&client->dev, "vref");
 176         if (IS_ERR(adc->ref))
 177                 return PTR_ERR(adc->ref);
 178
 179         err = regulator_enable(adc->ref);
 180         if (err < 0)
 181                 return err;
 182
 183         err = devm_add_action_or_reset(&client->dev, adc081c_reg_disable,
 184                                        adc->ref);
 185         if (err)
 186                 return err;
 187
 188         iio->name = dev_name(&client->dev);
 189         iio->modes = INDIO_DIRECT_MODE;
 190         iio->info = &adc081c_info;
 191
 192         iio->channels = model->channels;
 193         iio->num_channels = ADC081C_NUM_CHANNELS;
 194
 195         err = devm_iio_triggered_buffer_setup(&client->dev, iio, NULL,
 196                                               adc081c_trigger_handler, NULL);
 197         if (err < 0) {
 198                 dev_err(&client->dev, "iio triggered buffer setup failed\n");
 199                 return err;
 200         }
 201
 202         return devm_iio_device_register(&client->dev, iio);
 203 }
 204
 205 static const struct i2c_device_id adc081c_id[] = {
 206         { "adc081c", ADC081C },
 207         { "adc101c", ADC101C },
 208         { "adc121c", ADC121C },
 209         { }
 210 };
 211 MODULE_DEVICE_TABLE(i2c, adc081c_id);
 212
 213 static const struct of_device_id adc081c_of_match[] = {
 214         { .compatible = "ti,adc081c" },
 215         { .compatible = "ti,adc101c" },
 216         { .compatible = "ti,adc121c" },
 217         { }
 218 };
 219 MODULE_DEVICE_TABLE(of, adc081c_of_match);
 220
 221 static struct i2c_driver adc081c_driver = {
 222         .driver = {
 223                 .name = "adc081c",
 224                 .of_match_table = adc081c_of_match,
 225         },
 226         .probe = adc081c_probe,
 227         .id_table = adc081c_id,
 228 };
 229 module_i2c_driver(adc081c_driver);
 230
 231 MODULE_AUTHOR("Thierry Reding <[email protected]>");
 232 MODULE_DESCRIPTION("Texas Instruments ADC081C/ADC101C/ADC121C driver");
 233 MODULE_LICENSE("GPL v2");