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"); 262