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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Analog Devices AD5272 digital potentiometer driver4 * Copyright (C) 2018 Phil Reid <preid@electromag.com.au>5 *6 * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5272_5274.pdf7 *8 * DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address9 * ad5272 1 1024 20, 50, 100 01011xx10 * ad5274 1 256 20, 100 01011xx11 */12 13#include <linux/delay.h>14#include <linux/gpio/consumer.h>15#include <linux/i2c.h>16#include <linux/iio/iio.h>17#include <linux/module.h>18#include <linux/mod_devicetable.h>19 20#define AD5272_RDAC_WR 121#define AD5272_RDAC_RD 222#define AD5272_RESET 423#define AD5272_CTL 724 25#define AD5272_RDAC_WR_EN BIT(1)26 27struct ad5272_cfg {28 int max_pos;29 int kohms;30 int shift;31};32 33enum ad5272_type {34 AD5272_020,35 AD5272_050,36 AD5272_100,37 AD5274_020,38 AD5274_100,39};40 41static const struct ad5272_cfg ad5272_cfg[] = {42 [AD5272_020] = { .max_pos = 1024, .kohms = 20 },43 [AD5272_050] = { .max_pos = 1024, .kohms = 50 },44 [AD5272_100] = { .max_pos = 1024, .kohms = 100 },45 [AD5274_020] = { .max_pos = 256, .kohms = 20, .shift = 2 },46 [AD5274_100] = { .max_pos = 256, .kohms = 100, .shift = 2 },47};48 49struct ad5272_data {50 struct i2c_client *client;51 struct mutex lock;52 const struct ad5272_cfg *cfg;53 u8 buf[2] __aligned(IIO_DMA_MINALIGN);54};55 56static const struct iio_chan_spec ad5272_channel = {57 .type = IIO_RESISTANCE,58 .output = 1,59 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),60 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),61};62 63static int ad5272_write(struct ad5272_data *data, int reg, int val)64{65 int ret;66 67 data->buf[0] = (reg << 2) | ((val >> 8) & 0x3);68 data->buf[1] = (u8)val;69 70 mutex_lock(&data->lock);71 ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));72 mutex_unlock(&data->lock);73 return ret < 0 ? ret : 0;74}75 76static int ad5272_read(struct ad5272_data *data, int reg, int *val)77{78 int ret;79 80 data->buf[0] = reg << 2;81 data->buf[1] = 0;82 83 mutex_lock(&data->lock);84 ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));85 if (ret < 0)86 goto error;87 88 ret = i2c_master_recv(data->client, data->buf, sizeof(data->buf));89 if (ret < 0)90 goto error;91 92 *val = ((data->buf[0] & 0x3) << 8) | data->buf[1];93 ret = 0;94error:95 mutex_unlock(&data->lock);96 return ret;97}98 99static int ad5272_read_raw(struct iio_dev *indio_dev,100 struct iio_chan_spec const *chan,101 int *val, int *val2, long mask)102{103 struct ad5272_data *data = iio_priv(indio_dev);104 int ret;105 106 switch (mask) {107 case IIO_CHAN_INFO_RAW: {108 ret = ad5272_read(data, AD5272_RDAC_RD, val);109 *val = *val >> data->cfg->shift;110 return ret ? ret : IIO_VAL_INT;111 }112 case IIO_CHAN_INFO_SCALE:113 *val = 1000 * data->cfg->kohms;114 *val2 = data->cfg->max_pos;115 return IIO_VAL_FRACTIONAL;116 }117 118 return -EINVAL;119}120 121static int ad5272_write_raw(struct iio_dev *indio_dev,122 struct iio_chan_spec const *chan,123 int val, int val2, long mask)124{125 struct ad5272_data *data = iio_priv(indio_dev);126 127 if (mask != IIO_CHAN_INFO_RAW)128 return -EINVAL;129 130 if (val >= data->cfg->max_pos || val < 0 || val2)131 return -EINVAL;132 133 return ad5272_write(data, AD5272_RDAC_WR, val << data->cfg->shift);134}135 136static const struct iio_info ad5272_info = {137 .read_raw = ad5272_read_raw,138 .write_raw = ad5272_write_raw,139};140 141static int ad5272_reset(struct ad5272_data *data)142{143 struct gpio_desc *reset_gpio;144 145 reset_gpio = devm_gpiod_get_optional(&data->client->dev, "reset",146 GPIOD_OUT_HIGH);147 if (IS_ERR(reset_gpio))148 return PTR_ERR(reset_gpio);149 150 if (reset_gpio) {151 udelay(1);152 gpiod_set_value(reset_gpio, 0);153 } else {154 ad5272_write(data, AD5272_RESET, 0);155 }156 usleep_range(1000, 2000);157 158 return 0;159}160 161static int ad5272_probe(struct i2c_client *client)162{163 const struct i2c_device_id *id = i2c_client_get_device_id(client);164 struct device *dev = &client->dev;165 struct iio_dev *indio_dev;166 struct ad5272_data *data;167 int ret;168 169 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));170 if (!indio_dev)171 return -ENOMEM;172 173 i2c_set_clientdata(client, indio_dev);174 175 data = iio_priv(indio_dev);176 data->client = client;177 mutex_init(&data->lock);178 data->cfg = &ad5272_cfg[id->driver_data];179 180 ret = ad5272_reset(data);181 if (ret)182 return ret;183 184 ret = ad5272_write(data, AD5272_CTL, AD5272_RDAC_WR_EN);185 if (ret < 0)186 return -ENODEV;187 188 indio_dev->info = &ad5272_info;189 indio_dev->channels = &ad5272_channel;190 indio_dev->num_channels = 1;191 indio_dev->name = client->name;192 193 return devm_iio_device_register(dev, indio_dev);194}195 196static const struct of_device_id ad5272_dt_ids[] = {197 { .compatible = "adi,ad5272-020", .data = (void *)AD5272_020 },198 { .compatible = "adi,ad5272-050", .data = (void *)AD5272_050 },199 { .compatible = "adi,ad5272-100", .data = (void *)AD5272_100 },200 { .compatible = "adi,ad5274-020", .data = (void *)AD5274_020 },201 { .compatible = "adi,ad5274-100", .data = (void *)AD5274_100 },202 {}203};204MODULE_DEVICE_TABLE(of, ad5272_dt_ids);205 206static const struct i2c_device_id ad5272_id[] = {207 { "ad5272-020", AD5272_020 },208 { "ad5272-050", AD5272_050 },209 { "ad5272-100", AD5272_100 },210 { "ad5274-020", AD5274_020 },211 { "ad5274-100", AD5274_100 },212 {}213};214MODULE_DEVICE_TABLE(i2c, ad5272_id);215 216static struct i2c_driver ad5272_driver = {217 .driver = {218 .name = "ad5272",219 .of_match_table = ad5272_dt_ids,220 },221 .probe = ad5272_probe,222 .id_table = ad5272_id,223};224 225module_i2c_driver(ad5272_driver);226 227MODULE_AUTHOR("Phil Reid <preid@eletromag.com.au>");228MODULE_DESCRIPTION("AD5272 digital potentiometer");229MODULE_LICENSE("GPL v2");230