1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * mcp4725.c - Support for Microchip MCP4725/6
4 *
5 * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
6 *
7 * Based on max517 by Roland Stigge <stigge@antcom.de>
8 *
9 * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
10 * (7-bit I2C slave address 0x60, the three LSBs can be configured in
11 * hardware)
12 */
13
14 #include <linux/module.h>
15 #include <linux/i2c.h>
16 #include <linux/err.h>
17 #include <linux/delay.h>
18 #include <linux/regulator/consumer.h>
19 #include <linux/mod_devicetable.h>
20 #include <linux/property.h>
21
22 #include <linux/iio/iio.h>
23 #include <linux/iio/sysfs.h>
24
25 #include <linux/iio/dac/mcp4725.h>
26
27 #define MCP4725_DRV_NAME "mcp4725"
28
29 #define MCP472X_REF_VDD 0x00
30 #define MCP472X_REF_VREF_UNBUFFERED 0x02
31 #define MCP472X_REF_VREF_BUFFERED 0x03
32
33 struct mcp4725_data {
34 struct i2c_client *client;
35 int id;
36 unsigned ref_mode;
37 bool vref_buffered;
38 u16 dac_value;
39 bool powerdown;
40 unsigned powerdown_mode;
41 struct regulator *vdd_reg;
42 struct regulator *vref_reg;
43 };
44
mcp4725_suspend(struct device *dev)45 static int __maybe_unused mcp4725_suspend(struct device *dev)
46 {
47 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
48 to_i2c_client(dev)));
49 u8 outbuf[2];
50 int ret;
51
52 outbuf[0] = (data->powerdown_mode + 1) << 4;
53 outbuf[1] = 0;
54 data->powerdown = true;
55
56 ret = i2c_master_send(data->client, outbuf, 2);
57 if (ret < 0)
58 return ret;
59 else if (ret != 2)
60 return -EIO;
61 return 0;
62 }
63
mcp4725_resume(struct device *dev)64 static int __maybe_unused mcp4725_resume(struct device *dev)
65 {
66 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
67 to_i2c_client(dev)));
68 u8 outbuf[2];
69 int ret;
70
71 /* restore previous DAC value */
72 outbuf[0] = (data->dac_value >> 8) & 0xf;
73 outbuf[1] = data->dac_value & 0xff;
74 data->powerdown = false;
75
76 ret = i2c_master_send(data->client, outbuf, 2);
77 if (ret < 0)
78 return ret;
79 else if (ret != 2)
80 return -EIO;
81 return 0;
82 }
83 static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
84
mcp4725_store_eeprom(struct device *dev, struct device_attribute *attr, const char *buf, size_t len)85 static ssize_t mcp4725_store_eeprom(struct device *dev,
86 struct device_attribute *attr, const char *buf, size_t len)
87 {
88 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
89 struct mcp4725_data *data = iio_priv(indio_dev);
90 int tries = 20;
91 u8 inoutbuf[3];
92 bool state;
93 int ret;
94
95 ret = strtobool(buf, &state);
96 if (ret < 0)
97 return ret;
98
99 if (!state)
100 return 0;
101
102 inoutbuf[0] = 0x60; /* write EEPROM */
103 inoutbuf[0] |= data->ref_mode << 3;
104 inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
105 inoutbuf[1] = data->dac_value >> 4;
106 inoutbuf[2] = (data->dac_value & 0xf) << 4;
107
108 ret = i2c_master_send(data->client, inoutbuf, 3);
109 if (ret < 0)
110 return ret;
111 else if (ret != 3)
112 return -EIO;
113
114 /* wait for write complete, takes up to 50ms */
115 while (tries--) {
116 msleep(20);
117 ret = i2c_master_recv(data->client, inoutbuf, 3);
118 if (ret < 0)
119 return ret;
120 else if (ret != 3)
121 return -EIO;
122
123 if (inoutbuf[0] & 0x80)
124 break;
125 }
126
127 if (tries < 0) {
128 dev_err(&data->client->dev,
129 "mcp4725_store_eeprom() failed, incomplete\n");
130 return -EIO;
131 }
132
133 return len;
134 }
135
136 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
137
138 static struct attribute *mcp4725_attributes[] = {
139 &iio_dev_attr_store_eeprom.dev_attr.attr,
140 NULL,
141 };
142
143 static const struct attribute_group mcp4725_attribute_group = {
144 .attrs = mcp4725_attributes,
145 };
146
147 static const char * const mcp4725_powerdown_modes[] = {
148 "1kohm_to_gnd",
149 "100kohm_to_gnd",
150 "500kohm_to_gnd"
151 };
152
153 static const char * const mcp4726_powerdown_modes[] = {
154 "1kohm_to_gnd",
155 "125kohm_to_gnd",
156 "640kohm_to_gnd"
157 };
158
mcp4725_get_powerdown_mode(struct iio_dev *indio_dev, const struct iio_chan_spec *chan)159 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
160 const struct iio_chan_spec *chan)
161 {
162 struct mcp4725_data *data = iio_priv(indio_dev);
163
164 return data->powerdown_mode;
165 }
166
mcp4725_set_powerdown_mode(struct iio_dev *indio_dev, const struct iio_chan_spec *chan, unsigned mode)167 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
168 const struct iio_chan_spec *chan, unsigned mode)
169 {
170 struct mcp4725_data *data = iio_priv(indio_dev);
171
172 data->powerdown_mode = mode;
173
174 return 0;
175 }
176
mcp4725_read_powerdown(struct iio_dev *indio_dev, uintptr_t private, const struct iio_chan_spec *chan, char *buf)177 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
178 uintptr_t private, const struct iio_chan_spec *chan, char *buf)
179 {
180 struct mcp4725_data *data = iio_priv(indio_dev);
181
182 return sprintf(buf, "%d\n", data->powerdown);
183 }
184
mcp4725_write_powerdown(struct iio_dev *indio_dev, uintptr_t private, const struct iio_chan_spec *chan, const char *buf, size_t len)185 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
186 uintptr_t private, const struct iio_chan_spec *chan,
187 const char *buf, size_t len)
188 {
189 struct mcp4725_data *data = iio_priv(indio_dev);
190 bool state;
191 int ret;
192
193 ret = strtobool(buf, &state);
194 if (ret)
195 return ret;
196
197 if (state)
198 ret = mcp4725_suspend(&data->client->dev);
199 else
200 ret = mcp4725_resume(&data->client->dev);
201 if (ret < 0)
202 return ret;
203
204 return len;
205 }
206
207 enum chip_id {
208 MCP4725,
209 MCP4726,
210 };
211
212 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
213 [MCP4725] = {
214 .items = mcp4725_powerdown_modes,
215 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
216 .get = mcp4725_get_powerdown_mode,
217 .set = mcp4725_set_powerdown_mode,
218 },
219 [MCP4726] = {
220 .items = mcp4726_powerdown_modes,
221 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
222 .get = mcp4725_get_powerdown_mode,
223 .set = mcp4725_set_powerdown_mode,
224 },
225 };
226
227 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
228 {
229 .name = "powerdown",
230 .read = mcp4725_read_powerdown,
231 .write = mcp4725_write_powerdown,
232 .shared = IIO_SEPARATE,
233 },
234 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
235 &mcp472x_powerdown_mode_enum[MCP4725]),
236 IIO_ENUM_AVAILABLE("powerdown_mode",
237 &mcp472x_powerdown_mode_enum[MCP4725]),
238 { },
239 };
240
241 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
242 {
243 .name = "powerdown",
244 .read = mcp4725_read_powerdown,
245 .write = mcp4725_write_powerdown,
246 .shared = IIO_SEPARATE,
247 },
248 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
249 &mcp472x_powerdown_mode_enum[MCP4726]),
250 IIO_ENUM_AVAILABLE("powerdown_mode",
251 &mcp472x_powerdown_mode_enum[MCP4726]),
252 { },
253 };
254
255 static const struct iio_chan_spec mcp472x_channel[] = {
256 [MCP4725] = {
257 .type = IIO_VOLTAGE,
258 .indexed = 1,
259 .output = 1,
260 .channel = 0,
261 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
262 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
263 .ext_info = mcp4725_ext_info,
264 },
265 [MCP4726] = {
266 .type = IIO_VOLTAGE,
267 .indexed = 1,
268 .output = 1,
269 .channel = 0,
270 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
271 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
272 .ext_info = mcp4726_ext_info,
273 },
274 };
275
mcp4725_set_value(struct iio_dev *indio_dev, int val)276 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
277 {
278 struct mcp4725_data *data = iio_priv(indio_dev);
279 u8 outbuf[2];
280 int ret;
281
282 if (val >= (1 << 12) || val < 0)
283 return -EINVAL;
284
285 outbuf[0] = (val >> 8) & 0xf;
286 outbuf[1] = val & 0xff;
287
288 ret = i2c_master_send(data->client, outbuf, 2);
289 if (ret < 0)
290 return ret;
291 else if (ret != 2)
292 return -EIO;
293 else
294 return 0;
295 }
296
mcp4726_set_cfg(struct iio_dev *indio_dev)297 static int mcp4726_set_cfg(struct iio_dev *indio_dev)
298 {
299 struct mcp4725_data *data = iio_priv(indio_dev);
300 u8 outbuf[3];
301 int ret;
302
303 outbuf[0] = 0x40;
304 outbuf[0] |= data->ref_mode << 3;
305 if (data->powerdown)
306 outbuf[0] |= data->powerdown << 1;
307 outbuf[1] = data->dac_value >> 4;
308 outbuf[2] = (data->dac_value & 0xf) << 4;
309
310 ret = i2c_master_send(data->client, outbuf, 3);
311 if (ret < 0)
312 return ret;
313 else if (ret != 3)
314 return -EIO;
315 else
316 return 0;
317 }
318
mcp4725_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int *val, int *val2, long mask)319 static int mcp4725_read_raw(struct iio_dev *indio_dev,
320 struct iio_chan_spec const *chan,
321 int *val, int *val2, long mask)
322 {
323 struct mcp4725_data *data = iio_priv(indio_dev);
324 int ret;
325
326 switch (mask) {
327 case IIO_CHAN_INFO_RAW:
328 *val = data->dac_value;
329 return IIO_VAL_INT;
330 case IIO_CHAN_INFO_SCALE:
331 if (data->ref_mode == MCP472X_REF_VDD)
332 ret = regulator_get_voltage(data->vdd_reg);
333 else
334 ret = regulator_get_voltage(data->vref_reg);
335
336 if (ret < 0)
337 return ret;
338
339 *val = ret / 1000;
340 *val2 = 12;
341 return IIO_VAL_FRACTIONAL_LOG2;
342 }
343 return -EINVAL;
344 }
345
mcp4725_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan, int val, int val2, long mask)346 static int mcp4725_write_raw(struct iio_dev *indio_dev,
347 struct iio_chan_spec const *chan,
348 int val, int val2, long mask)
349 {
350 struct mcp4725_data *data = iio_priv(indio_dev);
351 int ret;
352
353 switch (mask) {
354 case IIO_CHAN_INFO_RAW:
355 ret = mcp4725_set_value(indio_dev, val);
356 data->dac_value = val;
357 break;
358 default:
359 ret = -EINVAL;
360 break;
361 }
362
363 return ret;
364 }
365
366 static const struct iio_info mcp4725_info = {
367 .read_raw = mcp4725_read_raw,
368 .write_raw = mcp4725_write_raw,
369 .attrs = &mcp4725_attribute_group,
370 };
371
mcp4725_probe_dt(struct device *dev, struct mcp4725_platform_data *pdata)372 static int mcp4725_probe_dt(struct device *dev,
373 struct mcp4725_platform_data *pdata)
374 {
375 /* check if is the vref-supply defined */
376 pdata->use_vref = device_property_read_bool(dev, "vref-supply");
377 pdata->vref_buffered =
378 device_property_read_bool(dev, "microchip,vref-buffered");
379
380 return 0;
381 }
382
mcp4725_probe(struct i2c_client *client, const struct i2c_device_id *id)383 static int mcp4725_probe(struct i2c_client *client,
384 const struct i2c_device_id *id)
385 {
386 struct mcp4725_data *data;
387 struct iio_dev *indio_dev;
388 struct mcp4725_platform_data *pdata, pdata_dt;
389 u8 inbuf[4];
390 u8 pd;
391 u8 ref;
392 int err;
393
394 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
395 if (indio_dev == NULL)
396 return -ENOMEM;
397 data = iio_priv(indio_dev);
398 i2c_set_clientdata(client, indio_dev);
399 data->client = client;
400 if (dev_fwnode(&client->dev))
401 data->id = (enum chip_id)device_get_match_data(&client->dev);
402 else
403 data->id = id->driver_data;
404 pdata = dev_get_platdata(&client->dev);
405
406 if (!pdata) {
407 err = mcp4725_probe_dt(&client->dev, &pdata_dt);
408 if (err) {
409 dev_err(&client->dev,
410 "invalid platform or devicetree data");
411 return err;
412 }
413 pdata = &pdata_dt;
414 }
415
416 if (data->id == MCP4725 && pdata->use_vref) {
417 dev_err(&client->dev,
418 "external reference is unavailable on MCP4725");
419 return -EINVAL;
420 }
421
422 if (!pdata->use_vref && pdata->vref_buffered) {
423 dev_err(&client->dev,
424 "buffering is unavailable on the internal reference");
425 return -EINVAL;
426 }
427
428 if (!pdata->use_vref)
429 data->ref_mode = MCP472X_REF_VDD;
430 else
431 data->ref_mode = pdata->vref_buffered ?
432 MCP472X_REF_VREF_BUFFERED :
433 MCP472X_REF_VREF_UNBUFFERED;
434
435 data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
436 if (IS_ERR(data->vdd_reg))
437 return PTR_ERR(data->vdd_reg);
438
439 err = regulator_enable(data->vdd_reg);
440 if (err)
441 return err;
442
443 if (pdata->use_vref) {
444 data->vref_reg = devm_regulator_get(&client->dev, "vref");
445 if (IS_ERR(data->vref_reg)) {
446 err = PTR_ERR(data->vref_reg);
447 goto err_disable_vdd_reg;
448 }
449
450 err = regulator_enable(data->vref_reg);
451 if (err)
452 goto err_disable_vdd_reg;
453 }
454
455 indio_dev->name = id->name;
456 indio_dev->info = &mcp4725_info;
457 indio_dev->channels = &mcp472x_channel[id->driver_data];
458 indio_dev->num_channels = 1;
459 indio_dev->modes = INDIO_DIRECT_MODE;
460
461 /* read current DAC value and settings */
462 err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4);
463
464 if (err < 0) {
465 dev_err(&client->dev, "failed to read DAC value");
466 goto err_disable_vref_reg;
467 }
468 pd = (inbuf[0] >> 1) & 0x3;
469 data->powerdown = pd > 0;
470 data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
471 data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
472 if (data->id == MCP4726)
473 ref = (inbuf[3] >> 3) & 0x3;
474
475 if (data->id == MCP4726 && ref != data->ref_mode) {
476 dev_info(&client->dev,
477 "voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
478 data->ref_mode, ref, data->ref_mode);
479 err = mcp4726_set_cfg(indio_dev);
480 if (err < 0)
481 goto err_disable_vref_reg;
482 }
483
484 err = iio_device_register(indio_dev);
485 if (err)
486 goto err_disable_vref_reg;
487
488 return 0;
489
490 err_disable_vref_reg:
491 if (data->vref_reg)
492 regulator_disable(data->vref_reg);
493
494 err_disable_vdd_reg:
495 regulator_disable(data->vdd_reg);
496
497 return err;
498 }
499
mcp4725_remove(struct i2c_client *client)500 static int mcp4725_remove(struct i2c_client *client)
501 {
502 struct iio_dev *indio_dev = i2c_get_clientdata(client);
503 struct mcp4725_data *data = iio_priv(indio_dev);
504
505 iio_device_unregister(indio_dev);
506
507 if (data->vref_reg)
508 regulator_disable(data->vref_reg);
509 regulator_disable(data->vdd_reg);
510
511 return 0;
512 }
513
514 static const struct i2c_device_id mcp4725_id[] = {
515 { "mcp4725", MCP4725 },
516 { "mcp4726", MCP4726 },
517 { }
518 };
519 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
520
521 static const struct of_device_id mcp4725_of_match[] = {
522 {
523 .compatible = "microchip,mcp4725",
524 .data = (void *)MCP4725
525 },
526 {
527 .compatible = "microchip,mcp4726",
528 .data = (void *)MCP4726
529 },
530 { }
531 };
532 MODULE_DEVICE_TABLE(of, mcp4725_of_match);
533
534 static struct i2c_driver mcp4725_driver = {
535 .driver = {
536 .name = MCP4725_DRV_NAME,
537 .of_match_table = mcp4725_of_match,
538 .pm = &mcp4725_pm_ops,
539 },
540 .probe = mcp4725_probe,
541 .remove = mcp4725_remove,
542 .id_table = mcp4725_id,
543 };
544 module_i2c_driver(mcp4725_driver);
545
546 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
547 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
548 MODULE_LICENSE("GPL");
549