1 // SPDX-License-Identifier: GPL-2.0+
3 * Analog Devices AD5110 digital potentiometer driver
5 * Copyright (C) 2021 Mugilraj Dhavachelvan <dmugil2000@gmail.com>
7 * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5110_5112_5114.pdf
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>
16 #include <linux/iio/iio.h>
17 #include <linux/iio/sysfs.h>
20 #define AD5110_EEPROM_WR 1
21 #define AD5110_RDAC_WR 2
22 #define AD5110_SHUTDOWN 3
23 #define AD5110_RESET 4
24 #define AD5110_RDAC_RD 5
25 #define AD5110_EEPROM_RD 6
27 /* AD5110_EEPROM_RD data */
28 #define AD5110_WIPER_POS 0
29 #define AD5110_RESISTOR_TOL 1
31 #define AD5110_WIPER_RESISTANCE 70
49 static 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 },
60 struct i2c_client *client;
61 s16 tol; /* resistor tolerance */
64 const struct ad5110_cfg *cfg;
66 * DMA (thus cache coherency maintenance) requires the
67 * transfer buffers to live in their own cache lines.
69 u8 buf[2] ____cacheline_aligned;
72 static const struct iio_chan_spec ad5110_channels[] = {
74 .type = IIO_RESISTANCE,
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),
81 static int ad5110_read(struct ad5110_data *data, u8 cmd, int *val)
85 mutex_lock(&data->lock);
89 ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));
92 } else if (ret != sizeof(data->buf)) {
97 ret = i2c_master_recv_dmasafe(data->client, data->buf, 1);
100 } else if (ret != 1) {
109 mutex_unlock(&data->lock);
113 static int ad5110_write(struct ad5110_data *data, u8 cmd, u8 val)
117 mutex_lock(&data->lock);
121 ret = i2c_master_send_dmasafe(data->client, data->buf, sizeof(data->buf));
124 } else if (ret != sizeof(data->buf)) {
132 mutex_unlock(&data->lock);
136 static int ad5110_resistor_tol(struct ad5110_data *data, u8 cmd, int val)
140 ret = ad5110_read(data, cmd, &val);
144 data->tol = data->cfg->kohms * (val & GENMASK(6, 0)) * 10 / 8;
151 static ssize_t store_eeprom_show(struct device *dev,
152 struct device_attribute *attr,
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;
160 ret = ad5110_read(data, AD5110_EEPROM_RD, &val);
164 val = val >> data->cfg->shift;
165 return iio_format_value(buf, IIO_VAL_INT, 1, &val);
168 static ssize_t store_eeprom_store(struct device *dev,
169 struct device_attribute *attr,
170 const char *buf, size_t len)
172 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
173 struct ad5110_data *data = iio_priv(indio_dev);
176 ret = ad5110_write(data, AD5110_EEPROM_WR, 0);
178 dev_err(&data->client->dev, "RDAC to EEPROM write failed\n");
182 /* The storing of EEPROM data takes approximately 18 ms. */
188 static IIO_DEVICE_ATTR_RW(store_eeprom, 0);
190 static struct attribute *ad5110_attributes[] = {
191 &iio_dev_attr_store_eeprom.dev_attr.attr,
195 static const struct attribute_group ad5110_attribute_group = {
196 .attrs = ad5110_attributes,
199 static int ad5110_read_raw(struct iio_dev *indio_dev,
200 struct iio_chan_spec const *chan,
201 int *val, int *val2, long mask)
203 struct ad5110_data *data = iio_priv(indio_dev);
207 case IIO_CHAN_INFO_RAW:
208 ret = ad5110_read(data, AD5110_RDAC_RD, val);
212 *val = *val >> data->cfg->shift;
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:
230 static int ad5110_write_raw(struct iio_dev *indio_dev,
231 struct iio_chan_spec const *chan,
232 int val, int val2, long mask)
234 struct ad5110_data *data = iio_priv(indio_dev);
238 case IIO_CHAN_INFO_RAW:
239 if (val > data->cfg->max_pos || val < 0)
242 return ad5110_write(data, AD5110_RDAC_WR, val << data->cfg->shift);
243 case IIO_CHAN_INFO_ENABLE:
244 if (val < 0 || val > 1)
246 if (data->enable == val)
248 ret = ad5110_write(data, AD5110_SHUTDOWN, val ? 0 : 1);
258 static const struct iio_info ad5110_info = {
259 .read_raw = ad5110_read_raw,
260 .write_raw = ad5110_write_raw,
261 .attrs = &ad5110_attribute_group,
264 #define AD5110_COMPATIBLE(of_compatible, cfg) { \
265 .compatible = of_compatible, \
266 .data = &ad5110_cfg[cfg], \
269 static 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),
279 MODULE_DEVICE_TABLE(of, ad5110_of_match);
281 static const struct i2c_device_id ad5110_id[] = {
282 { "ad5110-10", AD5110_10 },
283 { "ad5110-80", AD5110_80 },
284 { "ad5112-05", AD5112_05 },
285 { "ad5112-10", AD5112_10 },
286 { "ad5112-80", AD5112_80 },
287 { "ad5114-10", AD5114_10 },
288 { "ad5114-80", AD5114_80 },
291 MODULE_DEVICE_TABLE(i2c, ad5110_id);
293 static int ad5110_probe(struct i2c_client *client)
295 struct device *dev = &client->dev;
296 struct iio_dev *indio_dev;
297 struct ad5110_data *data;
300 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
304 data = iio_priv(indio_dev);
305 data->client = client;
306 mutex_init(&data->lock);
308 data->cfg = device_get_match_data(dev);
310 /* refresh RDAC register with EEPROM */
311 ret = ad5110_write(data, AD5110_RESET, 0);
313 dev_err(dev, "Refresh RDAC with EEPROM failed\n");
317 ret = ad5110_resistor_tol(data, AD5110_EEPROM_RD, AD5110_RESISTOR_TOL);
319 dev_err(dev, "Read resistor tolerance failed\n");
323 indio_dev->modes = INDIO_DIRECT_MODE;
324 indio_dev->info = &ad5110_info;
325 indio_dev->channels = ad5110_channels;
326 indio_dev->num_channels = ARRAY_SIZE(ad5110_channels);
327 indio_dev->name = client->name;
329 return devm_iio_device_register(dev, indio_dev);
332 static struct i2c_driver ad5110_driver = {
335 .of_match_table = ad5110_of_match,
337 .probe_new = ad5110_probe,
338 .id_table = ad5110_id,
340 module_i2c_driver(ad5110_driver);
342 MODULE_AUTHOR("Mugilraj Dhavachelvan <dmugil2000@gmail.com>");
343 MODULE_DESCRIPTION("AD5110 digital potentiometer");
344 MODULE_LICENSE("GPL v2");