1 // SPDX-License-Identifier: GPL-2.0+
3 * Analog Devices AD5272 digital potentiometer driver
4 * Copyright (C) 2018 Phil Reid <preid@electromag.com.au>
6 * Datasheet: http://www.analog.com/media/en/technical-documentation/data-sheets/AD5272_5274.pdf
8 * DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address
9 * ad5272 1 1024 20, 50, 100 01011xx
10 * ad5274 1 256 20, 100 01011xx
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>
19 #define AD5272_RDAC_WR 1
20 #define AD5272_RDAC_RD 2
21 #define AD5272_RESET 4
24 #define AD5272_RDAC_WR_EN BIT(1)
40 static const struct ad5272_cfg ad5272_cfg[] = {
41 [AD5272_020] = { .max_pos = 1024, .kohms = 20 },
42 [AD5272_050] = { .max_pos = 1024, .kohms = 50 },
43 [AD5272_100] = { .max_pos = 1024, .kohms = 100 },
44 [AD5274_020] = { .max_pos = 256, .kohms = 20, .shift = 2 },
45 [AD5274_100] = { .max_pos = 256, .kohms = 100, .shift = 2 },
49 struct i2c_client *client;
51 const struct ad5272_cfg *cfg;
52 u8 buf[2] ____cacheline_aligned;
55 static const struct iio_chan_spec ad5272_channel = {
56 .type = IIO_RESISTANCE,
58 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
59 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
62 static int ad5272_write(struct ad5272_data *data, int reg, int val)
66 data->buf[0] = (reg << 2) | ((val >> 8) & 0x3);
67 data->buf[1] = (u8)val;
69 mutex_lock(&data->lock);
70 ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
71 mutex_unlock(&data->lock);
72 return ret < 0 ? ret : 0;
75 static int ad5272_read(struct ad5272_data *data, int reg, int *val)
79 data->buf[0] = reg << 2;
82 mutex_lock(&data->lock);
83 ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
87 ret = i2c_master_recv(data->client, data->buf, sizeof(data->buf));
91 *val = ((data->buf[0] & 0x3) << 8) | data->buf[1];
94 mutex_unlock(&data->lock);
98 static int ad5272_read_raw(struct iio_dev *indio_dev,
99 struct iio_chan_spec const *chan,
100 int *val, int *val2, long mask)
102 struct ad5272_data *data = iio_priv(indio_dev);
106 case IIO_CHAN_INFO_RAW: {
107 ret = ad5272_read(data, AD5272_RDAC_RD, val);
108 *val = *val >> data->cfg->shift;
109 return ret ? ret : IIO_VAL_INT;
111 case IIO_CHAN_INFO_SCALE:
112 *val = 1000 * data->cfg->kohms;
113 *val2 = data->cfg->max_pos;
114 return IIO_VAL_FRACTIONAL;
120 static int ad5272_write_raw(struct iio_dev *indio_dev,
121 struct iio_chan_spec const *chan,
122 int val, int val2, long mask)
124 struct ad5272_data *data = iio_priv(indio_dev);
126 if (mask != IIO_CHAN_INFO_RAW)
129 if (val >= data->cfg->max_pos || val < 0 || val2)
132 return ad5272_write(data, AD5272_RDAC_WR, val << data->cfg->shift);
135 static const struct iio_info ad5272_info = {
136 .read_raw = ad5272_read_raw,
137 .write_raw = ad5272_write_raw,
140 static int ad5272_reset(struct ad5272_data *data)
142 struct gpio_desc *reset_gpio;
144 reset_gpio = devm_gpiod_get_optional(&data->client->dev, "reset",
146 if (IS_ERR(reset_gpio))
147 return PTR_ERR(reset_gpio);
151 gpiod_set_value(reset_gpio, 1);
153 ad5272_write(data, AD5272_RESET, 0);
155 usleep_range(1000, 2000);
160 static int ad5272_probe(struct i2c_client *client,
161 const struct i2c_device_id *id)
163 struct device *dev = &client->dev;
164 struct iio_dev *indio_dev;
165 struct ad5272_data *data;
168 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
172 i2c_set_clientdata(client, indio_dev);
174 data = iio_priv(indio_dev);
175 data->client = client;
176 mutex_init(&data->lock);
177 data->cfg = &ad5272_cfg[id->driver_data];
179 ret = ad5272_reset(data);
183 ret = ad5272_write(data, AD5272_CTL, AD5272_RDAC_WR_EN);
187 indio_dev->dev.parent = dev;
188 indio_dev->info = &ad5272_info;
189 indio_dev->channels = &ad5272_channel;
190 indio_dev->num_channels = 1;
191 indio_dev->name = client->name;
193 return devm_iio_device_register(dev, indio_dev);
196 #if defined(CONFIG_OF)
197 static const struct of_device_id ad5272_dt_ids[] = {
198 { .compatible = "adi,ad5272-020", .data = (void *)AD5272_020 },
199 { .compatible = "adi,ad5272-050", .data = (void *)AD5272_050 },
200 { .compatible = "adi,ad5272-100", .data = (void *)AD5272_100 },
201 { .compatible = "adi,ad5274-020", .data = (void *)AD5274_020 },
202 { .compatible = "adi,ad5274-100", .data = (void *)AD5274_100 },
205 MODULE_DEVICE_TABLE(of, ad5272_dt_ids);
206 #endif /* CONFIG_OF */
208 static const struct i2c_device_id ad5272_id[] = {
209 { "ad5272-020", AD5272_020 },
210 { "ad5272-050", AD5272_050 },
211 { "ad5272-100", AD5272_100 },
212 { "ad5274-020", AD5274_020 },
213 { "ad5274-100", AD5274_100 },
216 MODULE_DEVICE_TABLE(i2c, ad5272_id);
218 static struct i2c_driver ad5272_driver = {
221 .of_match_table = of_match_ptr(ad5272_dt_ids),
223 .probe = ad5272_probe,
224 .id_table = ad5272_id,
227 module_i2c_driver(ad5272_driver);
229 MODULE_AUTHOR("Phil Reid <preid@eletromag.com.au>");
230 MODULE_DESCRIPTION("AD5272 digital potentiometer");
231 MODULE_LICENSE("GPL v2");