kernel/drivers/iio/adc/ti-adc081c.c

   1 /*
   2  * Copyright (C) 2012 Avionic Design GmbH
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8
   9 #include <linux/err.h>
  10 #include <linux/i2c.h>
  11 #include <linux/module.h>
  12 #include <linux/of.h>
  13
  14 #include <linux/iio/iio.h>
  15 #include <linux/regulator/consumer.h>
  16
  17 struct adc081c {
  18         struct i2c_client *i2c;
  19         struct regulator *ref;
  20 };
  21
  22 #define REG_CONV_RES 0x00
  23
  24 static int adc081c_read_raw(struct iio_dev *iio,
  25                             struct iio_chan_spec const *channel, int *value,
  26                             int *shift, long mask)
  27 {
  28         struct adc081c *adc = iio_priv(iio);
  29         int err;
  30
  31         switch (mask) {
  32         case IIO_CHAN_INFO_RAW:
  33                 err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
  34                 if (err < 0)
  35                         return err;
  36
  37                 *value = (err >> 4) & 0xff;
  38                 return IIO_VAL_INT;
  39
  40         case IIO_CHAN_INFO_SCALE:
  41                 err = regulator_get_voltage(adc->ref);
  42                 if (err < 0)
  43                         return err;
  44
  45                 *value = err / 1000;
  46                 *shift = 8;
  47
  48                 return IIO_VAL_FRACTIONAL_LOG2;
  49
  50         default:
  51                 break;
  52         }
  53
  54         return -EINVAL;
  55 }
  56
  57 static const struct iio_chan_spec adc081c_channel = {
  58         .type = IIO_VOLTAGE,
  59         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
  60         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
  61 };
  62
  63 static const struct iio_info adc081c_info = {
  64         .read_raw = adc081c_read_raw,
  65         .driver_module = THIS_MODULE,
  66 };
  67
  68 static int adc081c_probe(struct i2c_client *client,
  69                          const struct i2c_device_id *id)
  70 {
  71         struct iio_dev *iio;
  72         struct adc081c *adc;
  73         int err;
  74
  75         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
  76                 return -ENODEV;
  77
  78         iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
  79         if (!iio)
  80                 return -ENOMEM;
  81
  82         adc = iio_priv(iio);
  83         adc->i2c = client;
  84
  85         adc->ref = devm_regulator_get(&client->dev, "vref");
  86         if (IS_ERR(adc->ref))
  87                 return PTR_ERR(adc->ref);
  88
  89         err = regulator_enable(adc->ref);
  90         if (err < 0)
  91                 return err;
  92
  93         iio->dev.parent = &client->dev;
  94         iio->name = dev_name(&client->dev);
  95         iio->modes = INDIO_DIRECT_MODE;
  96         iio->info = &adc081c_info;
  97
  98         iio->channels = &adc081c_channel;
  99         iio->num_channels = 1;
 100
 101         err = iio_device_register(iio);
 102         if (err < 0)
 103                 goto regulator_disable;
 104
 105         i2c_set_clientdata(client, iio);
 106
 107         return 0;
 108
 109 regulator_disable:
 110         regulator_disable(adc->ref);
 111
 112         return err;
 113 }
 114
 115 static int adc081c_remove(struct i2c_client *client)
 116 {
 117         struct iio_dev *iio = i2c_get_clientdata(client);
 118         struct adc081c *adc = iio_priv(iio);
 119
 120         iio_device_unregister(iio);
 121         regulator_disable(adc->ref);
 122
 123         return 0;
 124 }
 125
 126 static const struct i2c_device_id adc081c_id[] = {
 127         { "adc081c", 0 },
 128         { }
 129 };
 130 MODULE_DEVICE_TABLE(i2c, adc081c_id);
 131
 132 #ifdef CONFIG_OF
 133 static const struct of_device_id adc081c_of_match[] = {
 134         { .compatible = "ti,adc081c" },
 135         { }
 136 };
 137 MODULE_DEVICE_TABLE(of, adc081c_of_match);
 138 #endif
 139
 140 static struct i2c_driver adc081c_driver = {
 141         .driver = {
 142                 .name = "adc081c",
 143                 .owner = THIS_MODULE,
 144                 .of_match_table = of_match_ptr(adc081c_of_match),
 145         },
 146         .probe = adc081c_probe,
 147         .remove = adc081c_remove,
 148         .id_table = adc081c_id,
 149 };
 150 module_i2c_driver(adc081c_driver);
 151
 152 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
 153 MODULE_DESCRIPTION("Texas Instruments ADC081C021/027 driver");
 154 MODULE_LICENSE("GPL v2");