1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * Analog Devices AD5110 digital potentiometer driver |
4 | * |
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.pdf |
8 | */ |
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 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 |
26 | |
27 | /* AD5110_EEPROM_RD data */ |
28 | #define AD5110_WIPER_POS 0 |
29 | #define AD5110_RESISTOR_TOL 1 |
30 | |
31 | #define AD5110_WIPER_RESISTANCE 70 |
32 | |
33 | struct ad5110_cfg { |
34 | int max_pos; |
35 | int kohms; |
36 | int shift; |
37 | }; |
38 | |
39 | enum 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 | |
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 }, |
57 | }; |
58 | |
59 | struct 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 the |
67 | * transfer buffers to live in their own cache lines. |
68 | */ |
69 | u8 buf[2] __aligned(IIO_DMA_MINALIGN); |
70 | }; |
71 | |
72 | static 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 | |
81 | static 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(client: data->client, buf: data->buf, count: 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(client: data->client, buf: data->buf, count: 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 | |
108 | error: |
109 | mutex_unlock(lock: &data->lock); |
110 | return ret; |
111 | } |
112 | |
113 | static 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(client: data->client, buf: data->buf, count: 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 | |
131 | error: |
132 | mutex_unlock(lock: &data->lock); |
133 | return ret; |
134 | } |
135 | |
136 | static int ad5110_resistor_tol(struct ad5110_data *data, u8 cmd, int val) |
137 | { |
138 | int ret; |
139 | |
140 | ret = ad5110_read(data, cmd, val: &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 | |
151 | static 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: &val); |
161 | if (ret) |
162 | return ret; |
163 | |
164 | val = val >> data->cfg->shift; |
165 | return iio_format_value(buf, IIO_VAL_INT, size: 1, vals: &val); |
166 | } |
167 | |
168 | static 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, val: 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(msecs: 20); |
184 | |
185 | return len; |
186 | } |
187 | |
188 | static IIO_DEVICE_ATTR_RW(store_eeprom, 0); |
189 | |
190 | static struct attribute *ad5110_attributes[] = { |
191 | &iio_dev_attr_store_eeprom.dev_attr.attr, |
192 | NULL |
193 | }; |
194 | |
195 | static const struct attribute_group ad5110_attribute_group = { |
196 | .attrs = ad5110_attributes, |
197 | }; |
198 | |
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) |
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 | |
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) |
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: 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: val ? 0 : 1); |
249 | if (ret) |
250 | return ret; |
251 | data->enable = val; |
252 | return 0; |
253 | default: |
254 | return -EINVAL; |
255 | } |
256 | } |
257 | |
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, |
262 | }; |
263 | |
264 | #define AD5110_COMPATIBLE(of_compatible, cfg) { \ |
265 | .compatible = of_compatible, \ |
266 | .data = &ad5110_cfg[cfg], \ |
267 | } |
268 | |
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), |
277 | { } |
278 | }; |
279 | MODULE_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 | |
286 | static 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 | }; |
296 | MODULE_DEVICE_TABLE(i2c, ad5110_id); |
297 | |
298 | static 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(parent: dev, sizeof_priv: 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, val: 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 | |
337 | static 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 | }; |
345 | module_i2c_driver(ad5110_driver); |
346 | |
347 | MODULE_AUTHOR("Mugilraj Dhavachelvan <dmugil2000@gmail.com>" ); |
348 | MODULE_DESCRIPTION("AD5110 digital potentiometer" ); |
349 | MODULE_LICENSE("GPL v2" ); |
350 | |