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1// SPDX-License-Identifier: GPL-2.02/*3 * Industrial I/O driver for Microchip digital potentiometers4 * Copyright (c) 2018 Axentia Technologies AB5 * Author: Peter Rosin <peda@axentia.se>6 *7 * Datasheet: http://www.microchip.com/downloads/en/DeviceDoc/22147a.pdf8 *9 * DEVID #Wipers #Positions Resistor Opts (kOhm)10 * mcp4017 1 128 5, 10, 50, 10011 * mcp4018 1 128 5, 10, 50, 10012 * mcp4019 1 128 5, 10, 50, 10013 */14 15#include <linux/err.h>16#include <linux/i2c.h>17#include <linux/iio/iio.h>18#include <linux/module.h>19#include <linux/mod_devicetable.h>20#include <linux/property.h>21 22#define MCP4018_WIPER_MAX 12723 24struct mcp4018_cfg {25 int kohms;26};27 28enum mcp4018_type {29 MCP4018_502,30 MCP4018_103,31 MCP4018_503,32 MCP4018_104,33};34 35static const struct mcp4018_cfg mcp4018_cfg[] = {36 [MCP4018_502] = { .kohms = 5, },37 [MCP4018_103] = { .kohms = 10, },38 [MCP4018_503] = { .kohms = 50, },39 [MCP4018_104] = { .kohms = 100, },40};41 42struct mcp4018_data {43 struct i2c_client *client;44 const struct mcp4018_cfg *cfg;45};46 47static const struct iio_chan_spec mcp4018_channel = {48 .type = IIO_RESISTANCE,49 .indexed = 1,50 .output = 1,51 .channel = 0,52 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),53 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),54};55 56static int mcp4018_read_raw(struct iio_dev *indio_dev,57 struct iio_chan_spec const *chan,58 int *val, int *val2, long mask)59{60 struct mcp4018_data *data = iio_priv(indio_dev);61 s32 ret;62 63 switch (mask) {64 case IIO_CHAN_INFO_RAW:65 ret = i2c_smbus_read_byte(data->client);66 if (ret < 0)67 return ret;68 *val = ret;69 return IIO_VAL_INT;70 case IIO_CHAN_INFO_SCALE:71 *val = 1000 * data->cfg->kohms;72 *val2 = MCP4018_WIPER_MAX;73 return IIO_VAL_FRACTIONAL;74 }75 76 return -EINVAL;77}78 79static int mcp4018_write_raw(struct iio_dev *indio_dev,80 struct iio_chan_spec const *chan,81 int val, int val2, long mask)82{83 struct mcp4018_data *data = iio_priv(indio_dev);84 85 switch (mask) {86 case IIO_CHAN_INFO_RAW:87 if (val > MCP4018_WIPER_MAX || val < 0)88 return -EINVAL;89 break;90 default:91 return -EINVAL;92 }93 94 return i2c_smbus_write_byte(data->client, val);95}96 97static const struct iio_info mcp4018_info = {98 .read_raw = mcp4018_read_raw,99 .write_raw = mcp4018_write_raw,100};101 102#define MCP4018_ID_TABLE(_name, cfg) { \103 .name = _name, \104 .driver_data = (kernel_ulong_t)&mcp4018_cfg[cfg], \105}106 107static const struct i2c_device_id mcp4018_id[] = {108 MCP4018_ID_TABLE("mcp4017-502", MCP4018_502),109 MCP4018_ID_TABLE("mcp4017-103", MCP4018_103),110 MCP4018_ID_TABLE("mcp4017-503", MCP4018_503),111 MCP4018_ID_TABLE("mcp4017-104", MCP4018_104),112 MCP4018_ID_TABLE("mcp4018-502", MCP4018_502),113 MCP4018_ID_TABLE("mcp4018-103", MCP4018_103),114 MCP4018_ID_TABLE("mcp4018-503", MCP4018_503),115 MCP4018_ID_TABLE("mcp4018-104", MCP4018_104),116 MCP4018_ID_TABLE("mcp4019-502", MCP4018_502),117 MCP4018_ID_TABLE("mcp4019-103", MCP4018_103),118 MCP4018_ID_TABLE("mcp4019-503", MCP4018_503),119 MCP4018_ID_TABLE("mcp4019-104", MCP4018_104),120 { /* sentinel */ }121};122MODULE_DEVICE_TABLE(i2c, mcp4018_id);123 124#define MCP4018_COMPATIBLE(of_compatible, cfg) { \125 .compatible = of_compatible, \126 .data = &mcp4018_cfg[cfg], \127}128 129static const struct of_device_id mcp4018_of_match[] = {130 MCP4018_COMPATIBLE("microchip,mcp4017-502", MCP4018_502),131 MCP4018_COMPATIBLE("microchip,mcp4017-103", MCP4018_103),132 MCP4018_COMPATIBLE("microchip,mcp4017-503", MCP4018_503),133 MCP4018_COMPATIBLE("microchip,mcp4017-104", MCP4018_104),134 MCP4018_COMPATIBLE("microchip,mcp4018-502", MCP4018_502),135 MCP4018_COMPATIBLE("microchip,mcp4018-103", MCP4018_103),136 MCP4018_COMPATIBLE("microchip,mcp4018-503", MCP4018_503),137 MCP4018_COMPATIBLE("microchip,mcp4018-104", MCP4018_104),138 MCP4018_COMPATIBLE("microchip,mcp4019-502", MCP4018_502),139 MCP4018_COMPATIBLE("microchip,mcp4019-103", MCP4018_103),140 MCP4018_COMPATIBLE("microchip,mcp4019-503", MCP4018_503),141 MCP4018_COMPATIBLE("microchip,mcp4019-104", MCP4018_104),142 { /* sentinel */ }143};144MODULE_DEVICE_TABLE(of, mcp4018_of_match);145 146static int mcp4018_probe(struct i2c_client *client)147{148 struct device *dev = &client->dev;149 struct mcp4018_data *data;150 struct iio_dev *indio_dev;151 152 if (!i2c_check_functionality(client->adapter,153 I2C_FUNC_SMBUS_BYTE)) {154 dev_err(dev, "SMBUS Byte transfers not supported\n");155 return -EOPNOTSUPP;156 }157 158 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));159 if (!indio_dev)160 return -ENOMEM;161 data = iio_priv(indio_dev);162 i2c_set_clientdata(client, indio_dev);163 data->client = client;164 165 data->cfg = i2c_get_match_data(client);166 167 indio_dev->info = &mcp4018_info;168 indio_dev->channels = &mcp4018_channel;169 indio_dev->num_channels = 1;170 indio_dev->name = client->name;171 172 return devm_iio_device_register(dev, indio_dev);173}174 175static struct i2c_driver mcp4018_driver = {176 .driver = {177 .name = "mcp4018",178 .of_match_table = mcp4018_of_match,179 },180 .probe = mcp4018_probe,181 .id_table = mcp4018_id,182};183 184module_i2c_driver(mcp4018_driver);185 186MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");187MODULE_DESCRIPTION("MCP4018 digital potentiometer");188MODULE_LICENSE("GPL v2");189