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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Maxim Integrated DS1803 and similar digital potentiometer driver4 * Copyright (c) 2016 Slawomir Stepien5 * Copyright (c) 2022 Jagath Jog J6 *7 * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS1803.pdf8 * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3502.pdf9 *10 * DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address11 * ds1803 2 256 10, 50, 100 0101xxx12 * ds3502 1 128 10 01010xx13 */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 0xA924#define DS1803_WIPER_1 0xAA25#define DS3502_WR_IVR 0x0026 27enum ds1803_type {28 DS1803_010,29 DS1803_050,30 DS1803_100,31 DS3502,32};33 34struct 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 44struct 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 60static const struct iio_chan_spec ds1803_channels[] = {61 DS1803_CHANNEL(0, DS1803_WIPER_0),62 DS1803_CHANNEL(1, DS1803_WIPER_1),63};64 65static const struct iio_chan_spec ds3502_channels[] = {66 DS1803_CHANNEL(0, DS3502_WR_IVR),67};68 69static 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 85static 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 100static 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 135static 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 159static 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 182static 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 199static 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 205static 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 229static 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};236MODULE_DEVICE_TABLE(of, ds1803_dt_ids);237 238static 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};245MODULE_DEVICE_TABLE(i2c, ds1803_id);246 247static 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 256module_i2c_driver(ds1803_driver);257 258MODULE_AUTHOR("Slawomir Stepien <sst@poczta.fm>");259MODULE_AUTHOR("Jagath Jog J <jagathjog1996@gmail.com>");260MODULE_DESCRIPTION("DS1803 digital potentiometer");261MODULE_LICENSE("GPL v2");262