drivers/iio/potentiometer/tpl0102.c

   1 /*
   2  * tpl0102.c - Support for Texas Instruments digital potentiometers
   3  *
   4  * Copyright (C) 2016 Matt Ranostay <mranostay@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * TODO: enable/disable hi-z output control
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/i2c.h>
  21 #include <linux/regmap.h>
  22 #include <linux/iio/iio.h>
  23
  24 struct tpl0102_cfg {
  25         int wipers;
  26         int max_pos;
  27         int kohms;
  28 };
  29
  30 enum tpl0102_type {
  31         CAT5140_503,
  32         CAT5140_104,
  33         TPL0102_104,
  34         TPL0401_103,
  35 };
  36
  37 static const struct tpl0102_cfg tpl0102_cfg[] = {
  38         /* on-semiconductor parts */
  39         [CAT5140_503] = { .wipers = 1, .max_pos = 256, .kohms = 50, },
  40         [CAT5140_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, },
  41         /* ti parts */
  42         [TPL0102_104] = { .wipers = 2, .max_pos = 256, .kohms = 100 },
  43         [TPL0401_103] = { .wipers = 1, .max_pos = 128, .kohms = 10, },
  44 };
  45
  46 struct tpl0102_data {
  47         struct regmap *regmap;
  48         unsigned long devid;
  49 };
  50
  51 static const struct regmap_config tpl0102_regmap_config = {
  52         .reg_bits = 8,
  53         .val_bits = 8,
  54 };
  55
  56 #define TPL0102_CHANNEL(ch) {                                   \
  57         .type = IIO_RESISTANCE,                                 \
  58         .indexed = 1,                                           \
  59         .output = 1,                                            \
  60         .channel = (ch),                                        \
  61         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  62         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  63 }
  64
  65 static const struct iio_chan_spec tpl0102_channels[] = {
  66         TPL0102_CHANNEL(0),
  67         TPL0102_CHANNEL(1),
  68 };
  69
  70 static int tpl0102_read_raw(struct iio_dev *indio_dev,
  71                             struct iio_chan_spec const *chan,
  72                             int *val, int *val2, long mask)
  73 {
  74         struct tpl0102_data *data = iio_priv(indio_dev);
  75
  76         switch (mask) {
  77         case IIO_CHAN_INFO_RAW: {
  78                 int ret = regmap_read(data->regmap, chan->channel, val);
  79
  80                 return ret ? ret : IIO_VAL_INT;
  81         }
  82         case IIO_CHAN_INFO_SCALE:
  83                 *val = 1000 * tpl0102_cfg[data->devid].kohms;
  84                 *val2 = tpl0102_cfg[data->devid].max_pos;
  85                 return IIO_VAL_FRACTIONAL;
  86         }
  87
  88         return -EINVAL;
  89 }
  90
  91 static int tpl0102_write_raw(struct iio_dev *indio_dev,
  92                              struct iio_chan_spec const *chan,
  93                              int val, int val2, long mask)
  94 {
  95         struct tpl0102_data *data = iio_priv(indio_dev);
  96
  97         if (mask != IIO_CHAN_INFO_RAW)
  98                 return -EINVAL;
  99
 100         if (val >= tpl0102_cfg[data->devid].max_pos || val < 0)
 101                 return -EINVAL;
 102
 103         return regmap_write(data->regmap, chan->channel, val);
 104 }
 105
 106 static const struct iio_info tpl0102_info = {
 107         .read_raw = tpl0102_read_raw,
 108         .write_raw = tpl0102_write_raw,
 109         .driver_module = THIS_MODULE,
 110 };
 111
 112 static int tpl0102_probe(struct i2c_client *client,
 113                          const struct i2c_device_id *id)
 114 {
 115         struct device *dev = &client->dev;
 116         struct tpl0102_data *data;
 117         struct iio_dev *indio_dev;
 118
 119         indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 120         if (!indio_dev)
 121                 return -ENOMEM;
 122         data = iio_priv(indio_dev);
 123         i2c_set_clientdata(client, indio_dev);
 124
 125         data->devid = id->driver_data;
 126         data->regmap = devm_regmap_init_i2c(client, &tpl0102_regmap_config);
 127         if (IS_ERR(data->regmap)) {
 128                 dev_err(dev, "regmap initialization failed\n");
 129                 return PTR_ERR(data->regmap);
 130         }
 131
 132         indio_dev->dev.parent = dev;
 133         indio_dev->info = &tpl0102_info;
 134         indio_dev->channels = tpl0102_channels;
 135         indio_dev->num_channels = tpl0102_cfg[data->devid].wipers;
 136         indio_dev->name = client->name;
 137
 138         return devm_iio_device_register(dev, indio_dev);
 139 }
 140
 141 static const struct i2c_device_id tpl0102_id[] = {
 142         { "cat5140-503", CAT5140_503 },
 143         { "cat5140-104", CAT5140_104 },
 144         { "tpl0102-104", TPL0102_104 },
 145         { "tpl0401-103", TPL0401_103 },
 146         {}
 147 };
 148 MODULE_DEVICE_TABLE(i2c, tpl0102_id);
 149
 150 static struct i2c_driver tpl0102_driver = {
 151         .driver = {
 152                 .name = "tpl0102",
 153         },
 154         .probe = tpl0102_probe,
 155         .id_table = tpl0102_id,
 156 };
 157
 158 module_i2c_driver(tpl0102_driver);
 159
 160 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
 161 MODULE_DESCRIPTION("TPL0102 digital potentiometer");
 162 MODULE_LICENSE("GPL");