drivers/iio/potentiometer/ds1803.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Maxim Integrated DS1803 and similar digital potentiometer driver
   4  * Copyright (c) 2016 Slawomir Stepien
   5  * Copyright (c) 2022 Jagath Jog J
   6  *
   7  * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS1803.pdf
   8  * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3502.pdf
   9  *
  10  * DEVID        #Wipers #Positions      Resistor Opts (kOhm)    i2c address
  11  * ds1803       2       256             10, 50, 100             0101xxx
  12  * ds3502       1       128             10                      01010xx
  13  */
  14
  15 #include <linux/err.h>
  16 #include <linux/export.h>
  17 #include <linux/i2c.h>
  18 #include <linux/iio/iio.h>
  19 #include <linux/module.h>
  20 #include <linux/mod_devicetable.h>
  21 #include <linux/property.h>
  22
  23 #define DS1803_WIPER_0         0xA9
  24 #define DS1803_WIPER_1         0xAA
  25 #define DS3502_WR_IVR          0x00
  26
  27 enum ds1803_type {
  28         DS1803_010,
  29         DS1803_050,
  30         DS1803_100,
  31         DS3502,
  32 };
  33
  34 struct ds1803_cfg {
  35         int wipers;
  36         int avail[3];
  37         int kohms;
  38         const struct iio_chan_spec *channels;
  39         u8 num_channels;
  40         int (*read)(struct iio_dev *indio_dev,
  41                     struct iio_chan_spec const *chan, int *val);
  42 };
  43
  44 struct ds1803_data {
  45         struct i2c_client *client;
  46         const struct ds1803_cfg *cfg;
  47 };
  48
  49 #define DS1803_CHANNEL(ch, addr) {                                      \
  50         .type = IIO_RESISTANCE,                                         \
  51         .indexed = 1,                                                   \
  52         .output = 1,                                                    \
  53         .channel = (ch),                                                \
  54         .address = (addr),                                              \
  55         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),                   \
  56         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),           \
  57         .info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_RAW),   \
  58 }
  59
  60 static const struct iio_chan_spec ds1803_channels[] = {
  61         DS1803_CHANNEL(0, DS1803_WIPER_0),
  62         DS1803_CHANNEL(1, DS1803_WIPER_1),
  63 };
  64
  65 static const struct iio_chan_spec ds3502_channels[] = {
  66         DS1803_CHANNEL(0, DS3502_WR_IVR),
  67 };
  68
  69 static int ds1803_read(struct iio_dev *indio_dev,
  70                        struct iio_chan_spec const *chan,
  71                        int *val)
  72 {
  73         struct ds1803_data *data = iio_priv(indio_dev);
  74         int ret;
  75         u8 result[ARRAY_SIZE(ds1803_channels)];
  76
  77         ret = i2c_master_recv(data->client, result, indio_dev->num_channels);
  78         if (ret < 0)
  79                 return ret;
  80
  81         *val = result[chan->channel];
  82         return ret;
  83 }
  84
  85 static int ds3502_read(struct iio_dev *indio_dev,
  86                        struct iio_chan_spec const *chan,
  87                        int *val)
  88 {
  89         struct ds1803_data *data = iio_priv(indio_dev);
  90         int ret;
  91
  92         ret = i2c_smbus_read_byte_data(data->client, chan->address);
  93         if (ret < 0)
  94                 return ret;
  95
  96         *val = ret;
  97         return ret;
  98 }
  99
 100 static const struct ds1803_cfg ds1803_cfg[] = {
 101         [DS1803_010] = {
 102                 .wipers = 2,
 103                 .avail = { 0, 1, 255 },
 104                 .kohms =  10,
 105                 .channels = ds1803_channels,
 106                 .num_channels = ARRAY_SIZE(ds1803_channels),
 107                 .read = ds1803_read,
 108         },
 109         [DS1803_050] = {
 110                 .wipers = 2,
 111                 .avail = { 0, 1, 255 },
 112                 .kohms =  50,
 113                 .channels = ds1803_channels,
 114                 .num_channels = ARRAY_SIZE(ds1803_channels),
 115                 .read = ds1803_read,
 116         },
 117         [DS1803_100] = {
 118                 .wipers = 2,
 119                 .avail = { 0, 1, 255 },
 120                 .kohms = 100,
 121                 .channels = ds1803_channels,
 122                 .num_channels = ARRAY_SIZE(ds1803_channels),
 123                 .read = ds1803_read,
 124         },
 125         [DS3502] = {
 126           .wipers = 1,
 127           .avail = { 0, 1, 127 },
 128           .kohms =  10,
 129           .channels = ds3502_channels,
 130           .num_channels = ARRAY_SIZE(ds3502_channels),
 131           .read = ds3502_read,
 132         },
 133 };
 134
 135 static int ds1803_read_raw(struct iio_dev *indio_dev,
 136                            struct iio_chan_spec const *chan,
 137                            int *val, int *val2, long mask)
 138 {
 139         struct ds1803_data *data = iio_priv(indio_dev);
 140         int ret;
 141
 142         switch (mask) {
 143         case IIO_CHAN_INFO_RAW:
 144                 ret = data->cfg->read(indio_dev, chan, val);
 145                 if (ret < 0)
 146                         return ret;
 147
 148                 return IIO_VAL_INT;
 149
 150         case IIO_CHAN_INFO_SCALE:
 151                 *val = 1000 * data->cfg->kohms;
 152                 *val2 = data->cfg->avail[2]; /* Max wiper position */
 153                 return IIO_VAL_FRACTIONAL;
 154         }
 155
 156         return -EINVAL;
 157 }
 158
 159 static int ds1803_write_raw(struct iio_dev *indio_dev,
 160                             struct iio_chan_spec const *chan,
 161                             int val, int val2, long mask)
 162 {
 163         struct ds1803_data *data = iio_priv(indio_dev);
 164         u8 addr = chan->address;
 165         int max_pos = data->cfg->avail[2];
 166
 167         if (val2 != 0)
 168                 return -EINVAL;
 169
 170         switch (mask) {
 171         case IIO_CHAN_INFO_RAW:
 172                 if (val > max_pos || val < 0)
 173                         return -EINVAL;
 174                 break;
 175         default:
 176                 return -EINVAL;
 177         }
 178
 179         return i2c_smbus_write_byte_data(data->client, addr, val);
 180 }
 181
 182 static int ds1803_read_avail(struct iio_dev *indio_dev,
 183                              struct iio_chan_spec const *chan,
 184                              const int **vals, int *type,
 185                              int *length, long mask)
 186 {
 187         struct ds1803_data *data = iio_priv(indio_dev);
 188
 189         switch (mask) {
 190         case IIO_CHAN_INFO_RAW:
 191                 *vals = data->cfg->avail;
 192                 *length = ARRAY_SIZE(data->cfg->avail);
 193                 *type = IIO_VAL_INT;
 194                 return IIO_AVAIL_RANGE;
 195         }
 196         return -EINVAL;
 197 }
 198
 199 static const struct iio_info ds1803_info = {
 200         .read_raw = ds1803_read_raw,
 201         .write_raw = ds1803_write_raw,
 202         .read_avail = ds1803_read_avail,
 203 };
 204
 205 static int ds1803_probe(struct i2c_client *client)
 206 {
 207         struct device *dev = &client->dev;
 208         struct ds1803_data *data;
 209         struct iio_dev *indio_dev;
 210
 211         indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 212         if (!indio_dev)
 213                 return -ENOMEM;
 214
 215         i2c_set_clientdata(client, indio_dev);
 216
 217         data = iio_priv(indio_dev);
 218         data->client = client;
 219         data->cfg = i2c_get_match_data(client);
 220
 221         indio_dev->info = &ds1803_info;
 222         indio_dev->channels = data->cfg->channels;
 223         indio_dev->num_channels = data->cfg->num_channels;
 224         indio_dev->name = client->name;
 225
 226         return devm_iio_device_register(dev, indio_dev);
 227 }
 228
 229 static const struct of_device_id ds1803_dt_ids[] = {
 230         { .compatible = "maxim,ds1803-010", .data = &ds1803_cfg[DS1803_010] },
 231         { .compatible = "maxim,ds1803-050", .data = &ds1803_cfg[DS1803_050] },
 232         { .compatible = "maxim,ds1803-100", .data = &ds1803_cfg[DS1803_100] },
 233         { .compatible = "maxim,ds3502", .data = &ds1803_cfg[DS3502] },
 234         {}
 235 };
 236 MODULE_DEVICE_TABLE(of, ds1803_dt_ids);
 237
 238 static const struct i2c_device_id ds1803_id[] = {
 239         { "ds1803-010", (kernel_ulong_t)&ds1803_cfg[DS1803_010] },
 240         { "ds1803-050", (kernel_ulong_t)&ds1803_cfg[DS1803_050] },
 241         { "ds1803-100", (kernel_ulong_t)&ds1803_cfg[DS1803_100] },
 242         { "ds3502", (kernel_ulong_t)&ds1803_cfg[DS3502] },
 243         {}
 244 };
 245 MODULE_DEVICE_TABLE(i2c, ds1803_id);
 246
 247 static struct i2c_driver ds1803_driver = {
 248         .driver = {
 249                 .name   = "ds1803",
 250                 .of_match_table = ds1803_dt_ids,
 251         },
 252         .probe          = ds1803_probe,
 253         .id_table       = ds1803_id,
 254 };
 255
 256 module_i2c_driver(ds1803_driver);
 257
 258 MODULE_AUTHOR("Slawomir Stepien <sst@poczta.fm>");
 259 MODULE_AUTHOR("Jagath Jog J <jagathjog1996@gmail.com>");
 260 MODULE_DESCRIPTION("DS1803 digital potentiometer");
 261 MODULE_LICENSE("GPL v2");