drivers/iio/potentiometer/mcp4531.c

   1 /*
   2  * Industrial I/O driver for Microchip digital potentiometers
   3  * Copyright (c) 2015  Axentia Technologies AB
   4  * Author: Peter Rosin <peda@axentia.se>
   5  *
   6  * Datasheet: http://www.microchip.com/downloads/en/DeviceDoc/22096b.pdf
   7  *
   8  * DEVID        #Wipers #Positions      Resistor Opts (kOhm)    i2c address
   9  * mcp4531      1       129             5, 10, 50, 100          010111x
  10  * mcp4532      1       129             5, 10, 50, 100          01011xx
  11  * mcp4551      1       257             5, 10, 50, 100          010111x
  12  * mcp4552      1       257             5, 10, 50, 100          01011xx
  13  * mcp4631      2       129             5, 10, 50, 100          0101xxx
  14  * mcp4632      2       129             5, 10, 50, 100          01011xx
  15  * mcp4651      2       257             5, 10, 50, 100          0101xxx
  16  * mcp4652      2       257             5, 10, 50, 100          01011xx
  17  *
  18  * This program is free software; you can redistribute it and/or modify it
  19  * under the terms of the GNU General Public License version 2 as published by
  20  * the Free Software Foundation.
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/i2c.h>
  25 #include <linux/err.h>
  26
  27 #include <linux/iio/iio.h>
  28
  29 struct mcp4531_cfg {
  30         int wipers;
  31         int max_pos;
  32         int kohms;
  33 };
  34
  35 enum mcp4531_type {
  36         MCP453x_502,
  37         MCP453x_103,
  38         MCP453x_503,
  39         MCP453x_104,
  40         MCP455x_502,
  41         MCP455x_103,
  42         MCP455x_503,
  43         MCP455x_104,
  44         MCP463x_502,
  45         MCP463x_103,
  46         MCP463x_503,
  47         MCP463x_104,
  48         MCP465x_502,
  49         MCP465x_103,
  50         MCP465x_503,
  51         MCP465x_104,
  52 };
  53
  54 static const struct mcp4531_cfg mcp4531_cfg[] = {
  55         [MCP453x_502] = { .wipers = 1, .max_pos = 128, .kohms =   5, },
  56         [MCP453x_103] = { .wipers = 1, .max_pos = 128, .kohms =  10, },
  57         [MCP453x_503] = { .wipers = 1, .max_pos = 128, .kohms =  50, },
  58         [MCP453x_104] = { .wipers = 1, .max_pos = 128, .kohms = 100, },
  59         [MCP455x_502] = { .wipers = 1, .max_pos = 256, .kohms =   5, },
  60         [MCP455x_103] = { .wipers = 1, .max_pos = 256, .kohms =  10, },
  61         [MCP455x_503] = { .wipers = 1, .max_pos = 256, .kohms =  50, },
  62         [MCP455x_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, },
  63         [MCP463x_502] = { .wipers = 2, .max_pos = 128, .kohms =   5, },
  64         [MCP463x_103] = { .wipers = 2, .max_pos = 128, .kohms =  10, },
  65         [MCP463x_503] = { .wipers = 2, .max_pos = 128, .kohms =  50, },
  66         [MCP463x_104] = { .wipers = 2, .max_pos = 128, .kohms = 100, },
  67         [MCP465x_502] = { .wipers = 2, .max_pos = 256, .kohms =   5, },
  68         [MCP465x_103] = { .wipers = 2, .max_pos = 256, .kohms =  10, },
  69         [MCP465x_503] = { .wipers = 2, .max_pos = 256, .kohms =  50, },
  70         [MCP465x_104] = { .wipers = 2, .max_pos = 256, .kohms = 100, },
  71 };
  72
  73 #define MCP4531_WRITE (0 << 2)
  74 #define MCP4531_INCR  (1 << 2)
  75 #define MCP4531_DECR  (2 << 2)
  76 #define MCP4531_READ  (3 << 2)
  77
  78 #define MCP4531_WIPER_SHIFT (4)
  79
  80 struct mcp4531_data {
  81         struct i2c_client *client;
  82         const struct mcp4531_cfg *cfg;
  83 };
  84
  85 #define MCP4531_CHANNEL(ch) {                                   \
  86         .type = IIO_RESISTANCE,                                 \
  87         .indexed = 1,                                           \
  88         .output = 1,                                            \
  89         .channel = (ch),                                        \
  90         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  91         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  92 }
  93
  94 static const struct iio_chan_spec mcp4531_channels[] = {
  95         MCP4531_CHANNEL(0),
  96         MCP4531_CHANNEL(1),
  97 };
  98
  99 static int mcp4531_read_raw(struct iio_dev *indio_dev,
 100                             struct iio_chan_spec const *chan,
 101                             int *val, int *val2, long mask)
 102 {
 103         struct mcp4531_data *data = iio_priv(indio_dev);
 104         int address = chan->channel << MCP4531_WIPER_SHIFT;
 105         s32 ret;
 106
 107         switch (mask) {
 108         case IIO_CHAN_INFO_RAW:
 109                 ret = i2c_smbus_read_word_swapped(data->client,
 110                                                   MCP4531_READ | address);
 111                 if (ret < 0)
 112                         return ret;
 113                 *val = ret;
 114                 return IIO_VAL_INT;
 115         case IIO_CHAN_INFO_SCALE:
 116                 *val = 1000 * data->cfg->kohms;
 117                 *val2 = data->cfg->max_pos;
 118                 return IIO_VAL_FRACTIONAL;
 119         }
 120
 121         return -EINVAL;
 122 }
 123
 124 static int mcp4531_write_raw(struct iio_dev *indio_dev,
 125                              struct iio_chan_spec const *chan,
 126                              int val, int val2, long mask)
 127 {
 128         struct mcp4531_data *data = iio_priv(indio_dev);
 129         int address = chan->channel << MCP4531_WIPER_SHIFT;
 130
 131         switch (mask) {
 132         case IIO_CHAN_INFO_RAW:
 133                 if (val > data->cfg->max_pos || val < 0)
 134                         return -EINVAL;
 135                 break;
 136         default:
 137                 return -EINVAL;
 138         }
 139
 140         return i2c_smbus_write_byte_data(data->client,
 141                                          MCP4531_WRITE | address | (val >> 8),
 142                                          val & 0xff);
 143 }
 144
 145 static const struct iio_info mcp4531_info = {
 146         .read_raw = mcp4531_read_raw,
 147         .write_raw = mcp4531_write_raw,
 148         .driver_module = THIS_MODULE,
 149 };
 150
 151 static int mcp4531_probe(struct i2c_client *client,
 152                          const struct i2c_device_id *id)
 153 {
 154         struct device *dev = &client->dev;
 155         struct mcp4531_data *data;
 156         struct iio_dev *indio_dev;
 157
 158         if (!i2c_check_functionality(client->adapter,
 159                                      I2C_FUNC_SMBUS_WORD_DATA)) {
 160                 dev_err(dev, "SMBUS Word Data not supported\n");
 161                 return -EOPNOTSUPP;
 162         }
 163
 164         indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 165         if (!indio_dev)
 166                 return -ENOMEM;
 167         data = iio_priv(indio_dev);
 168         i2c_set_clientdata(client, indio_dev);
 169         data->client = client;
 170         data->cfg = &mcp4531_cfg[id->driver_data];
 171
 172         indio_dev->dev.parent = dev;
 173         indio_dev->info = &mcp4531_info;
 174         indio_dev->channels = mcp4531_channels;
 175         indio_dev->num_channels = data->cfg->wipers;
 176         indio_dev->name = client->name;
 177
 178         return devm_iio_device_register(dev, indio_dev);
 179 }
 180
 181 static const struct i2c_device_id mcp4531_id[] = {
 182         { "mcp4531-502", MCP453x_502 },
 183         { "mcp4531-103", MCP453x_103 },
 184         { "mcp4531-503", MCP453x_503 },
 185         { "mcp4531-104", MCP453x_104 },
 186         { "mcp4532-502", MCP453x_502 },
 187         { "mcp4532-103", MCP453x_103 },
 188         { "mcp4532-503", MCP453x_503 },
 189         { "mcp4532-104", MCP453x_104 },
 190         { "mcp4551-502", MCP455x_502 },
 191         { "mcp4551-103", MCP455x_103 },
 192         { "mcp4551-503", MCP455x_503 },
 193         { "mcp4551-104", MCP455x_104 },
 194         { "mcp4552-502", MCP455x_502 },
 195         { "mcp4552-103", MCP455x_103 },
 196         { "mcp4552-503", MCP455x_503 },
 197         { "mcp4552-104", MCP455x_104 },
 198         { "mcp4631-502", MCP463x_502 },
 199         { "mcp4631-103", MCP463x_103 },
 200         { "mcp4631-503", MCP463x_503 },
 201         { "mcp4631-104", MCP463x_104 },
 202         { "mcp4632-502", MCP463x_502 },
 203         { "mcp4632-103", MCP463x_103 },
 204         { "mcp4632-503", MCP463x_503 },
 205         { "mcp4632-104", MCP463x_104 },
 206         { "mcp4651-502", MCP465x_502 },
 207         { "mcp4651-103", MCP465x_103 },
 208         { "mcp4651-503", MCP465x_503 },
 209         { "mcp4651-104", MCP465x_104 },
 210         { "mcp4652-502", MCP465x_502 },
 211         { "mcp4652-103", MCP465x_103 },
 212         { "mcp4652-503", MCP465x_503 },
 213         { "mcp4652-104", MCP465x_104 },
 214         {}
 215 };
 216 MODULE_DEVICE_TABLE(i2c, mcp4531_id);
 217
 218 static struct i2c_driver mcp4531_driver = {
 219         .driver = {
 220                 .name   = "mcp4531",
 221         },
 222         .probe          = mcp4531_probe,
 223         .id_table       = mcp4531_id,
 224 };
 225
 226 module_i2c_driver(mcp4531_driver);
 227
 228 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
 229 MODULE_DESCRIPTION("MCP4531 digital potentiometer");
 230 MODULE_LICENSE("GPL");