// SPDX-License-Identifier: GPL-2.0+
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/*
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* Analog Devices AD5272 digital potentiometer driver
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* Copyright (C) 2018 Phil Reid <preid@electromag.com.au>
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*
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* Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5272_5274.pdf
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*
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* DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address
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* ad5272 1 1024 20, 50, 100 01011xx
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* ad5274 1 256 20, 100 01011xx
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*/
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#include <linux/delay.h>
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#include <linux/gpio/consumer.h>
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#include <linux/i2c.h>
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#include <linux/iio/iio.h>
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#include <linux/module.h>
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#include <linux/mod_devicetable.h>
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#define AD5272_RDAC_WR 1
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#define AD5272_RDAC_RD 2
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#define AD5272_RESET 4
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#define AD5272_CTL 7
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#define AD5272_RDAC_WR_EN BIT(1)
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struct ad5272_cfg {
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int max_pos;
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int kohms;
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int shift;
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};
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enum ad5272_type {
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AD5272_020,
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AD5272_050,
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AD5272_100,
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AD5274_020,
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AD5274_100,
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};
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static const struct ad5272_cfg ad5272_cfg[] = {
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[AD5272_020] = { .max_pos = 1024, .kohms = 20 },
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[AD5272_050] = { .max_pos = 1024, .kohms = 50 },
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[AD5272_100] = { .max_pos = 1024, .kohms = 100 },
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[AD5274_020] = { .max_pos = 256, .kohms = 20, .shift = 2 },
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[AD5274_100] = { .max_pos = 256, .kohms = 100, .shift = 2 },
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};
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struct ad5272_data {
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struct i2c_client *client;
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struct mutex lock;
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const struct ad5272_cfg *cfg;
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u8 buf[2] ____cacheline_aligned;
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};
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static const struct iio_chan_spec ad5272_channel = {
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.type = IIO_RESISTANCE,
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.output = 1,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
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};
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static int ad5272_write(struct ad5272_data *data, int reg, int val)
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{
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int ret;
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data->buf[0] = (reg << 2) | ((val >> 8) & 0x3);
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data->buf[1] = (u8)val;
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mutex_lock(&data->lock);
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ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
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mutex_unlock(&data->lock);
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return ret < 0 ? ret : 0;
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}
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static int ad5272_read(struct ad5272_data *data, int reg, int *val)
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{
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int ret;
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data->buf[0] = reg << 2;
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data->buf[1] = 0;
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mutex_lock(&data->lock);
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ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
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if (ret < 0)
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goto error;
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ret = i2c_master_recv(data->client, data->buf, sizeof(data->buf));
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if (ret < 0)
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goto error;
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*val = ((data->buf[0] & 0x3) << 8) | data->buf[1];
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ret = 0;
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error:
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mutex_unlock(&data->lock);
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return ret;
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}
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static int ad5272_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct ad5272_data *data = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW: {
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ret = ad5272_read(data, AD5272_RDAC_RD, val);
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*val = *val >> data->cfg->shift;
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return ret ? ret : IIO_VAL_INT;
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}
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case IIO_CHAN_INFO_SCALE:
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*val = 1000 * data->cfg->kohms;
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*val2 = data->cfg->max_pos;
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return IIO_VAL_FRACTIONAL;
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}
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return -EINVAL;
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}
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static int ad5272_write_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int val, int val2, long mask)
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{
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struct ad5272_data *data = iio_priv(indio_dev);
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if (mask != IIO_CHAN_INFO_RAW)
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return -EINVAL;
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if (val >= data->cfg->max_pos || val < 0 || val2)
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return -EINVAL;
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return ad5272_write(data, AD5272_RDAC_WR, val << data->cfg->shift);
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}
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static const struct iio_info ad5272_info = {
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.read_raw = ad5272_read_raw,
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.write_raw = ad5272_write_raw,
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};
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static int ad5272_reset(struct ad5272_data *data)
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{
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struct gpio_desc *reset_gpio;
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reset_gpio = devm_gpiod_get_optional(&data->client->dev, "reset",
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GPIOD_OUT_LOW);
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if (IS_ERR(reset_gpio))
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return PTR_ERR(reset_gpio);
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if (reset_gpio) {
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udelay(1);
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gpiod_set_value(reset_gpio, 1);
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} else {
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ad5272_write(data, AD5272_RESET, 0);
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}
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usleep_range(1000, 2000);
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return 0;
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}
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static int ad5272_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct device *dev = &client->dev;
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struct iio_dev *indio_dev;
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struct ad5272_data *data;
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int ret;
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indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
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if (!indio_dev)
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return -ENOMEM;
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i2c_set_clientdata(client, indio_dev);
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data = iio_priv(indio_dev);
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data->client = client;
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mutex_init(&data->lock);
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data->cfg = &ad5272_cfg[id->driver_data];
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ret = ad5272_reset(data);
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if (ret)
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return ret;
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ret = ad5272_write(data, AD5272_CTL, AD5272_RDAC_WR_EN);
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if (ret < 0)
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return -ENODEV;
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indio_dev->info = &ad5272_info;
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indio_dev->channels = &ad5272_channel;
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indio_dev->num_channels = 1;
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indio_dev->name = client->name;
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return devm_iio_device_register(dev, indio_dev);
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}
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static const struct of_device_id ad5272_dt_ids[] = {
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{ .compatible = "adi,ad5272-020", .data = (void *)AD5272_020 },
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{ .compatible = "adi,ad5272-050", .data = (void *)AD5272_050 },
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{ .compatible = "adi,ad5272-100", .data = (void *)AD5272_100 },
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{ .compatible = "adi,ad5274-020", .data = (void *)AD5274_020 },
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{ .compatible = "adi,ad5274-100", .data = (void *)AD5274_100 },
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{}
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};
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MODULE_DEVICE_TABLE(of, ad5272_dt_ids);
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static const struct i2c_device_id ad5272_id[] = {
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{ "ad5272-020", AD5272_020 },
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{ "ad5272-050", AD5272_050 },
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{ "ad5272-100", AD5272_100 },
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{ "ad5274-020", AD5274_020 },
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{ "ad5274-100", AD5274_100 },
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{}
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};
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MODULE_DEVICE_TABLE(i2c, ad5272_id);
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static struct i2c_driver ad5272_driver = {
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.driver = {
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.name = "ad5272",
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.of_match_table = ad5272_dt_ids,
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},
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.probe = ad5272_probe,
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.id_table = ad5272_id,
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};
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module_i2c_driver(ad5272_driver);
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MODULE_AUTHOR("Phil Reid <preid@eletromag.com.au>");
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MODULE_DESCRIPTION("AD5272 digital potentiometer");
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MODULE_LICENSE("GPL v2");
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