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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Analog Devices AD5110 digital potentiometer driver4 *5 * Copyright (C) 2021 Mugilraj Dhavachelvan <dmugil2000@gmail.com>6 *7 * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5110_5112_5114.pdf8 */9 10#include <linux/bitfield.h>11#include <linux/delay.h>12#include <linux/device.h>13#include <linux/i2c.h>14#include <linux/module.h>15 16#include <linux/iio/iio.h>17#include <linux/iio/sysfs.h>18 19/* AD5110 commands */20#define AD5110_EEPROM_WR 121#define AD5110_RDAC_WR 222#define AD5110_SHUTDOWN 323#define AD5110_RESET 424#define AD5110_RDAC_RD 525#define AD5110_EEPROM_RD 626 27/* AD5110_EEPROM_RD data */28#define AD5110_WIPER_POS 029#define AD5110_RESISTOR_TOL 130 31#define AD5110_WIPER_RESISTANCE 7032 33struct ad5110_cfg {34 int max_pos;35 int kohms;36 int shift;37};38 39enum ad5110_type {40 AD5110_10,41 AD5110_80,42 AD5112_05,43 AD5112_10,44 AD5112_80,45 AD5114_10,46 AD5114_80,47};48 49static const struct ad5110_cfg ad5110_cfg[] = {50 [AD5110_10] = { .max_pos = 128, .kohms = 10 },51 [AD5110_80] = { .max_pos = 128, .kohms = 80 },52 [AD5112_05] = { .max_pos = 64, .kohms = 5, .shift = 1 },53 [AD5112_10] = { .max_pos = 64, .kohms = 10, .shift = 1 },54 [AD5112_80] = { .max_pos = 64, .kohms = 80, .shift = 1 },55 [AD5114_10] = { .max_pos = 32, .kohms = 10, .shift = 2 },56 [AD5114_80] = { .max_pos = 32, .kohms = 80, .shift = 2 },57};58 59struct ad5110_data {60 struct i2c_client *client;61 s16 tol; /* resistor tolerance */62 bool enable;63 struct mutex lock;64 const struct ad5110_cfg *cfg;65 /*66 * DMA (thus cache coherency maintenance) may require the67 * transfer buffers to live in their own cache lines.68 */69 u8 buf[2] __aligned(IIO_DMA_MINALIGN);70};71 72static const struct iio_chan_spec ad5110_channels[] = {73 {74 .type = IIO_RESISTANCE,75 .output = 1,76 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_OFFSET) |77 BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_ENABLE),78 },79};80 81static int ad5110_read(struct ad5110_data *data, u8 cmd, int *val)82{83 int ret;84 85 mutex_lock(&data->lock);86 data->buf[0] = cmd;87 data->buf[1] = *val;88 89 ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));90 if (ret < 0) {91 goto error;92 } else if (ret != sizeof(data->buf)) {93 ret = -EIO;94 goto error;95 }96 97 ret = i2c_master_recv_dmasafe(data->client, data->buf, 1);98 if (ret < 0) {99 goto error;100 } else if (ret != 1) {101 ret = -EIO;102 goto error;103 }104 105 *val = data->buf[0];106 ret = 0;107 108error:109 mutex_unlock(&data->lock);110 return ret;111}112 113static int ad5110_write(struct ad5110_data *data, u8 cmd, u8 val)114{115 int ret;116 117 mutex_lock(&data->lock);118 data->buf[0] = cmd;119 data->buf[1] = val;120 121 ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));122 if (ret < 0) {123 goto error;124 } else if (ret != sizeof(data->buf)) {125 ret = -EIO;126 goto error;127 }128 129 ret = 0;130 131error:132 mutex_unlock(&data->lock);133 return ret;134}135 136static int ad5110_resistor_tol(struct ad5110_data *data, u8 cmd, int val)137{138 int ret;139 140 ret = ad5110_read(data, cmd, &val);141 if (ret)142 return ret;143 144 data->tol = data->cfg->kohms * (val & GENMASK(6, 0)) * 10 / 8;145 if (!(val & BIT(7)))146 data->tol *= -1;147 148 return 0;149}150 151static ssize_t store_eeprom_show(struct device *dev,152 struct device_attribute *attr,153 char *buf)154{155 struct iio_dev *indio_dev = dev_to_iio_dev(dev);156 struct ad5110_data *data = iio_priv(indio_dev);157 int val = AD5110_WIPER_POS;158 int ret;159 160 ret = ad5110_read(data, AD5110_EEPROM_RD, &val);161 if (ret)162 return ret;163 164 val = val >> data->cfg->shift;165 return iio_format_value(buf, IIO_VAL_INT, 1, &val);166}167 168static ssize_t store_eeprom_store(struct device *dev,169 struct device_attribute *attr,170 const char *buf, size_t len)171{172 struct iio_dev *indio_dev = dev_to_iio_dev(dev);173 struct ad5110_data *data = iio_priv(indio_dev);174 int ret;175 176 ret = ad5110_write(data, AD5110_EEPROM_WR, 0);177 if (ret) {178 dev_err(&data->client->dev, "RDAC to EEPROM write failed\n");179 return ret;180 }181 182 /* The storing of EEPROM data takes approximately 18 ms. */183 msleep(20);184 185 return len;186}187 188static IIO_DEVICE_ATTR_RW(store_eeprom, 0);189 190static struct attribute *ad5110_attributes[] = {191 &iio_dev_attr_store_eeprom.dev_attr.attr,192 NULL193};194 195static const struct attribute_group ad5110_attribute_group = {196 .attrs = ad5110_attributes,197};198 199static int ad5110_read_raw(struct iio_dev *indio_dev,200 struct iio_chan_spec const *chan,201 int *val, int *val2, long mask)202{203 struct ad5110_data *data = iio_priv(indio_dev);204 int ret;205 206 switch (mask) {207 case IIO_CHAN_INFO_RAW:208 ret = ad5110_read(data, AD5110_RDAC_RD, val);209 if (ret)210 return ret;211 212 *val = *val >> data->cfg->shift;213 return IIO_VAL_INT;214 case IIO_CHAN_INFO_OFFSET:215 *val = AD5110_WIPER_RESISTANCE * data->cfg->max_pos;216 *val2 = 1000 * data->cfg->kohms + data->tol;217 return IIO_VAL_FRACTIONAL;218 case IIO_CHAN_INFO_SCALE:219 *val = 1000 * data->cfg->kohms + data->tol;220 *val2 = data->cfg->max_pos;221 return IIO_VAL_FRACTIONAL;222 case IIO_CHAN_INFO_ENABLE:223 *val = data->enable;224 return IIO_VAL_INT;225 default:226 return -EINVAL;227 }228}229 230static int ad5110_write_raw(struct iio_dev *indio_dev,231 struct iio_chan_spec const *chan,232 int val, int val2, long mask)233{234 struct ad5110_data *data = iio_priv(indio_dev);235 int ret;236 237 switch (mask) {238 case IIO_CHAN_INFO_RAW:239 if (val > data->cfg->max_pos || val < 0)240 return -EINVAL;241 242 return ad5110_write(data, AD5110_RDAC_WR, val << data->cfg->shift);243 case IIO_CHAN_INFO_ENABLE:244 if (val < 0 || val > 1)245 return -EINVAL;246 if (data->enable == val)247 return 0;248 ret = ad5110_write(data, AD5110_SHUTDOWN, val ? 0 : 1);249 if (ret)250 return ret;251 data->enable = val;252 return 0;253 default:254 return -EINVAL;255 }256}257 258static const struct iio_info ad5110_info = {259 .read_raw = ad5110_read_raw,260 .write_raw = ad5110_write_raw,261 .attrs = &ad5110_attribute_group,262};263 264#define AD5110_COMPATIBLE(of_compatible, cfg) { \265 .compatible = of_compatible, \266 .data = &ad5110_cfg[cfg], \267}268 269static const struct of_device_id ad5110_of_match[] = {270 AD5110_COMPATIBLE("adi,ad5110-10", AD5110_10),271 AD5110_COMPATIBLE("adi,ad5110-80", AD5110_80),272 AD5110_COMPATIBLE("adi,ad5112-05", AD5112_05),273 AD5110_COMPATIBLE("adi,ad5112-10", AD5112_10),274 AD5110_COMPATIBLE("adi,ad5112-80", AD5112_80),275 AD5110_COMPATIBLE("adi,ad5114-10", AD5114_10),276 AD5110_COMPATIBLE("adi,ad5114-80", AD5114_80),277 { }278};279MODULE_DEVICE_TABLE(of, ad5110_of_match);280 281#define AD5110_ID_TABLE(_name, cfg) { \282 .name = _name, \283 .driver_data = (kernel_ulong_t)&ad5110_cfg[cfg], \284}285 286static const struct i2c_device_id ad5110_id[] = {287 AD5110_ID_TABLE("ad5110-10", AD5110_10),288 AD5110_ID_TABLE("ad5110-80", AD5110_80),289 AD5110_ID_TABLE("ad5112-05", AD5112_05),290 AD5110_ID_TABLE("ad5112-10", AD5112_10),291 AD5110_ID_TABLE("ad5112-80", AD5112_80),292 AD5110_ID_TABLE("ad5114-10", AD5114_10),293 AD5110_ID_TABLE("ad5114-80", AD5114_80),294 { }295};296MODULE_DEVICE_TABLE(i2c, ad5110_id);297 298static int ad5110_probe(struct i2c_client *client)299{300 struct device *dev = &client->dev;301 struct iio_dev *indio_dev;302 struct ad5110_data *data;303 int ret;304 305 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));306 if (!indio_dev)307 return -ENOMEM;308 309 data = iio_priv(indio_dev);310 data->client = client;311 mutex_init(&data->lock);312 data->enable = 1;313 data->cfg = i2c_get_match_data(client);314 315 /* refresh RDAC register with EEPROM */316 ret = ad5110_write(data, AD5110_RESET, 0);317 if (ret) {318 dev_err(dev, "Refresh RDAC with EEPROM failed\n");319 return ret;320 }321 322 ret = ad5110_resistor_tol(data, AD5110_EEPROM_RD, AD5110_RESISTOR_TOL);323 if (ret) {324 dev_err(dev, "Read resistor tolerance failed\n");325 return ret;326 }327 328 indio_dev->modes = INDIO_DIRECT_MODE;329 indio_dev->info = &ad5110_info;330 indio_dev->channels = ad5110_channels;331 indio_dev->num_channels = ARRAY_SIZE(ad5110_channels);332 indio_dev->name = client->name;333 334 return devm_iio_device_register(dev, indio_dev);335}336 337static struct i2c_driver ad5110_driver = {338 .driver = {339 .name = "ad5110",340 .of_match_table = ad5110_of_match,341 },342 .probe = ad5110_probe,343 .id_table = ad5110_id,344};345module_i2c_driver(ad5110_driver);346 347MODULE_AUTHOR("Mugilraj Dhavachelvan <dmugil2000@gmail.com>");348MODULE_DESCRIPTION("AD5110 digital potentiometer");349MODULE_LICENSE("GPL v2");350