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1// SPDX-License-Identifier: GPL-2.02/*3 * Industrial I/O driver for Microchip digital potentiometers4 *5 * Copyright (c) 2018 Chris Coffey <cmc@babblebit.net>6 * Based on: Slawomir Stepien's code from mcp4131.c7 *8 * Datasheet: https://ww1.microchip.com/downloads/en/devicedoc/11195c.pdf9 *10 * DEVID #Wipers #Positions Resistance (kOhm)11 * mcp41010 1 256 1012 * mcp41050 1 256 5013 * mcp41100 1 256 10014 * mcp42010 2 256 1015 * mcp42050 2 256 5016 * mcp42100 2 256 10017 */18 19#include <linux/cache.h>20#include <linux/err.h>21#include <linux/iio/iio.h>22#include <linux/iio/types.h>23#include <linux/module.h>24#include <linux/mod_devicetable.h>25#include <linux/mutex.h>26#include <linux/property.h>27#include <linux/spi/spi.h>28 29#define MCP41010_MAX_WIPERS 230#define MCP41010_WRITE BIT(4)31#define MCP41010_WIPER_MAX 25532#define MCP41010_WIPER_CHANNEL BIT(0)33 34struct mcp41010_cfg {35 char name[16];36 int wipers;37 int kohms;38};39 40enum mcp41010_type {41 MCP41010,42 MCP41050,43 MCP41100,44 MCP42010,45 MCP42050,46 MCP42100,47};48 49static const struct mcp41010_cfg mcp41010_cfg[] = {50 [MCP41010] = { .name = "mcp41010", .wipers = 1, .kohms = 10, },51 [MCP41050] = { .name = "mcp41050", .wipers = 1, .kohms = 50, },52 [MCP41100] = { .name = "mcp41100", .wipers = 1, .kohms = 100, },53 [MCP42010] = { .name = "mcp42010", .wipers = 2, .kohms = 10, },54 [MCP42050] = { .name = "mcp42050", .wipers = 2, .kohms = 50, },55 [MCP42100] = { .name = "mcp42100", .wipers = 2, .kohms = 100, },56};57 58struct mcp41010_data {59 struct spi_device *spi;60 const struct mcp41010_cfg *cfg;61 struct mutex lock; /* Protect write sequences */62 unsigned int value[MCP41010_MAX_WIPERS]; /* Cache wiper values */63 u8 buf[2] __aligned(IIO_DMA_MINALIGN);64};65 66#define MCP41010_CHANNEL(ch) { \67 .type = IIO_RESISTANCE, \68 .indexed = 1, \69 .output = 1, \70 .channel = (ch), \71 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \72 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \73}74 75static const struct iio_chan_spec mcp41010_channels[] = {76 MCP41010_CHANNEL(0),77 MCP41010_CHANNEL(1),78};79 80static int mcp41010_read_raw(struct iio_dev *indio_dev,81 struct iio_chan_spec const *chan,82 int *val, int *val2, long mask)83{84 struct mcp41010_data *data = iio_priv(indio_dev);85 int channel = chan->channel;86 87 switch (mask) {88 case IIO_CHAN_INFO_RAW:89 *val = data->value[channel];90 return IIO_VAL_INT;91 92 case IIO_CHAN_INFO_SCALE:93 *val = 1000 * data->cfg->kohms;94 *val2 = MCP41010_WIPER_MAX;95 return IIO_VAL_FRACTIONAL;96 }97 98 return -EINVAL;99}100 101static int mcp41010_write_raw(struct iio_dev *indio_dev,102 struct iio_chan_spec const *chan,103 int val, int val2, long mask)104{105 int err;106 struct mcp41010_data *data = iio_priv(indio_dev);107 int channel = chan->channel;108 109 if (mask != IIO_CHAN_INFO_RAW)110 return -EINVAL;111 112 if (val > MCP41010_WIPER_MAX || val < 0)113 return -EINVAL;114 115 mutex_lock(&data->lock);116 117 data->buf[0] = MCP41010_WIPER_CHANNEL << channel;118 data->buf[0] |= MCP41010_WRITE;119 data->buf[1] = val & 0xff;120 121 err = spi_write(data->spi, data->buf, sizeof(data->buf));122 if (!err)123 data->value[channel] = val;124 125 mutex_unlock(&data->lock);126 127 return err;128}129 130static const struct iio_info mcp41010_info = {131 .read_raw = mcp41010_read_raw,132 .write_raw = mcp41010_write_raw,133};134 135static int mcp41010_probe(struct spi_device *spi)136{137 int err;138 struct device *dev = &spi->dev;139 struct mcp41010_data *data;140 struct iio_dev *indio_dev;141 142 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));143 if (!indio_dev)144 return -ENOMEM;145 146 data = iio_priv(indio_dev);147 spi_set_drvdata(spi, indio_dev);148 data->spi = spi;149 data->cfg = device_get_match_data(&spi->dev);150 if (!data->cfg)151 data->cfg = &mcp41010_cfg[spi_get_device_id(spi)->driver_data];152 153 mutex_init(&data->lock);154 155 indio_dev->info = &mcp41010_info;156 indio_dev->channels = mcp41010_channels;157 indio_dev->num_channels = data->cfg->wipers;158 indio_dev->name = data->cfg->name;159 160 err = devm_iio_device_register(dev, indio_dev);161 if (err)162 dev_info(&spi->dev, "Unable to register %s\n", indio_dev->name);163 164 return err;165}166 167static const struct of_device_id mcp41010_match[] = {168 { .compatible = "microchip,mcp41010", .data = &mcp41010_cfg[MCP41010] },169 { .compatible = "microchip,mcp41050", .data = &mcp41010_cfg[MCP41050] },170 { .compatible = "microchip,mcp41100", .data = &mcp41010_cfg[MCP41100] },171 { .compatible = "microchip,mcp42010", .data = &mcp41010_cfg[MCP42010] },172 { .compatible = "microchip,mcp42050", .data = &mcp41010_cfg[MCP42050] },173 { .compatible = "microchip,mcp42100", .data = &mcp41010_cfg[MCP42100] },174 {}175};176MODULE_DEVICE_TABLE(of, mcp41010_match);177 178static const struct spi_device_id mcp41010_id[] = {179 { "mcp41010", MCP41010 },180 { "mcp41050", MCP41050 },181 { "mcp41100", MCP41100 },182 { "mcp42010", MCP42010 },183 { "mcp42050", MCP42050 },184 { "mcp42100", MCP42100 },185 {}186};187MODULE_DEVICE_TABLE(spi, mcp41010_id);188 189static struct spi_driver mcp41010_driver = {190 .driver = {191 .name = "mcp41010",192 .of_match_table = mcp41010_match,193 },194 .probe = mcp41010_probe,195 .id_table = mcp41010_id,196};197 198module_spi_driver(mcp41010_driver);199 200MODULE_AUTHOR("Chris Coffey <cmc@babblebit.net>");201MODULE_DESCRIPTION("MCP41010 digital potentiometer");202MODULE_LICENSE("GPL v2");203