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 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 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 DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend,
84 mcp4725_resume);
85
mcp4725_store_eeprom(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)86 static ssize_t mcp4725_store_eeprom(struct device *dev,
87 struct device_attribute *attr, const char *buf, size_t len)
88 {
89 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
90 struct mcp4725_data *data = iio_priv(indio_dev);
91 int tries = 20;
92 u8 inoutbuf[3];
93 bool state;
94 int ret;
95
96 ret = kstrtobool(buf, &state);
97 if (ret < 0)
98 return ret;
99
100 if (!state)
101 return 0;
102
103 inoutbuf[0] = 0x60; /* write EEPROM */
104 inoutbuf[0] |= data->ref_mode << 3;
105 inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
106 inoutbuf[1] = data->dac_value >> 4;
107 inoutbuf[2] = (data->dac_value & 0xf) << 4;
108
109 ret = i2c_master_send(data->client, inoutbuf, 3);
110 if (ret < 0)
111 return ret;
112 else if (ret != 3)
113 return -EIO;
114
115 /* wait for write complete, takes up to 50ms */
116 while (tries--) {
117 msleep(20);
118 ret = i2c_master_recv(data->client, inoutbuf, 3);
119 if (ret < 0)
120 return ret;
121 else if (ret != 3)
122 return -EIO;
123
124 if (inoutbuf[0] & 0x80)
125 break;
126 }
127
128 if (tries < 0) {
129 dev_err(&data->client->dev,
130 "mcp4725_store_eeprom() failed, incomplete\n");
131 return -EIO;
132 }
133
134 return len;
135 }
136
137 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
138
139 static struct attribute *mcp4725_attributes[] = {
140 &iio_dev_attr_store_eeprom.dev_attr.attr,
141 NULL,
142 };
143
144 static const struct attribute_group mcp4725_attribute_group = {
145 .attrs = mcp4725_attributes,
146 };
147
148 static const char * const mcp4725_powerdown_modes[] = {
149 "1kohm_to_gnd",
150 "100kohm_to_gnd",
151 "500kohm_to_gnd"
152 };
153
154 static const char * const mcp4726_powerdown_modes[] = {
155 "1kohm_to_gnd",
156 "125kohm_to_gnd",
157 "640kohm_to_gnd"
158 };
159
mcp4725_get_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan)160 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
161 const struct iio_chan_spec *chan)
162 {
163 struct mcp4725_data *data = iio_priv(indio_dev);
164
165 return data->powerdown_mode;
166 }
167
mcp4725_set_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,unsigned mode)168 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
169 const struct iio_chan_spec *chan, unsigned mode)
170 {
171 struct mcp4725_data *data = iio_priv(indio_dev);
172
173 data->powerdown_mode = mode;
174
175 return 0;
176 }
177
mcp4725_read_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)178 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
179 uintptr_t private, const struct iio_chan_spec *chan, char *buf)
180 {
181 struct mcp4725_data *data = iio_priv(indio_dev);
182
183 return sysfs_emit(buf, "%d\n", data->powerdown);
184 }
185
mcp4725_write_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)186 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
187 uintptr_t private, const struct iio_chan_spec *chan,
188 const char *buf, size_t len)
189 {
190 struct mcp4725_data *data = iio_priv(indio_dev);
191 bool state;
192 int ret;
193
194 ret = kstrtobool(buf, &state);
195 if (ret)
196 return ret;
197
198 if (state)
199 ret = mcp4725_suspend(&data->client->dev);
200 else
201 ret = mcp4725_resume(&data->client->dev);
202 if (ret < 0)
203 return ret;
204
205 return len;
206 }
207
208 enum chip_id {
209 MCP4725,
210 MCP4726,
211 };
212
213 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
214 [MCP4725] = {
215 .items = mcp4725_powerdown_modes,
216 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
217 .get = mcp4725_get_powerdown_mode,
218 .set = mcp4725_set_powerdown_mode,
219 },
220 [MCP4726] = {
221 .items = mcp4726_powerdown_modes,
222 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
223 .get = mcp4725_get_powerdown_mode,
224 .set = mcp4725_set_powerdown_mode,
225 },
226 };
227
228 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
229 {
230 .name = "powerdown",
231 .read = mcp4725_read_powerdown,
232 .write = mcp4725_write_powerdown,
233 .shared = IIO_SEPARATE,
234 },
235 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
236 &mcp472x_powerdown_mode_enum[MCP4725]),
237 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
238 &mcp472x_powerdown_mode_enum[MCP4725]),
239 { },
240 };
241
242 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
243 {
244 .name = "powerdown",
245 .read = mcp4725_read_powerdown,
246 .write = mcp4725_write_powerdown,
247 .shared = IIO_SEPARATE,
248 },
249 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
250 &mcp472x_powerdown_mode_enum[MCP4726]),
251 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
252 &mcp472x_powerdown_mode_enum[MCP4726]),
253 { },
254 };
255
256 static const struct iio_chan_spec mcp472x_channel[] = {
257 [MCP4725] = {
258 .type = IIO_VOLTAGE,
259 .indexed = 1,
260 .output = 1,
261 .channel = 0,
262 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
263 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
264 .ext_info = mcp4725_ext_info,
265 },
266 [MCP4726] = {
267 .type = IIO_VOLTAGE,
268 .indexed = 1,
269 .output = 1,
270 .channel = 0,
271 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
272 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
273 .ext_info = mcp4726_ext_info,
274 },
275 };
276
mcp4725_set_value(struct iio_dev * indio_dev,int val)277 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
278 {
279 struct mcp4725_data *data = iio_priv(indio_dev);
280 u8 outbuf[2];
281 int ret;
282
283 if (val >= (1 << 12) || val < 0)
284 return -EINVAL;
285
286 outbuf[0] = (val >> 8) & 0xf;
287 outbuf[1] = val & 0xff;
288
289 ret = i2c_master_send(data->client, outbuf, 2);
290 if (ret < 0)
291 return ret;
292 else if (ret != 2)
293 return -EIO;
294 else
295 return 0;
296 }
297
mcp4726_set_cfg(struct iio_dev * indio_dev)298 static int mcp4726_set_cfg(struct iio_dev *indio_dev)
299 {
300 struct mcp4725_data *data = iio_priv(indio_dev);
301 u8 outbuf[3];
302 int ret;
303
304 outbuf[0] = 0x40;
305 outbuf[0] |= data->ref_mode << 3;
306 if (data->powerdown)
307 outbuf[0] |= data->powerdown << 1;
308 outbuf[1] = data->dac_value >> 4;
309 outbuf[2] = (data->dac_value & 0xf) << 4;
310
311 ret = i2c_master_send(data->client, outbuf, 3);
312 if (ret < 0)
313 return ret;
314 else if (ret != 3)
315 return -EIO;
316 else
317 return 0;
318 }
319
mcp4725_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)320 static int mcp4725_read_raw(struct iio_dev *indio_dev,
321 struct iio_chan_spec const *chan,
322 int *val, int *val2, long mask)
323 {
324 struct mcp4725_data *data = iio_priv(indio_dev);
325 int ret;
326
327 switch (mask) {
328 case IIO_CHAN_INFO_RAW:
329 *val = data->dac_value;
330 return IIO_VAL_INT;
331 case IIO_CHAN_INFO_SCALE:
332 if (data->ref_mode == MCP472X_REF_VDD)
333 ret = regulator_get_voltage(data->vdd_reg);
334 else
335 ret = regulator_get_voltage(data->vref_reg);
336
337 if (ret < 0)
338 return ret;
339
340 *val = ret / 1000;
341 *val2 = 12;
342 return IIO_VAL_FRACTIONAL_LOG2;
343 }
344 return -EINVAL;
345 }
346
mcp4725_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)347 static int mcp4725_write_raw(struct iio_dev *indio_dev,
348 struct iio_chan_spec const *chan,
349 int val, int val2, long mask)
350 {
351 struct mcp4725_data *data = iio_priv(indio_dev);
352 int ret;
353
354 switch (mask) {
355 case IIO_CHAN_INFO_RAW:
356 ret = mcp4725_set_value(indio_dev, val);
357 data->dac_value = val;
358 break;
359 default:
360 ret = -EINVAL;
361 break;
362 }
363
364 return ret;
365 }
366
367 static const struct iio_info mcp4725_info = {
368 .read_raw = mcp4725_read_raw,
369 .write_raw = mcp4725_write_raw,
370 .attrs = &mcp4725_attribute_group,
371 };
372
mcp4725_probe_dt(struct device * dev,struct mcp4725_platform_data * pdata)373 static int mcp4725_probe_dt(struct device *dev,
374 struct mcp4725_platform_data *pdata)
375 {
376 /* check if is the vref-supply defined */
377 pdata->use_vref = device_property_read_bool(dev, "vref-supply");
378 pdata->vref_buffered =
379 device_property_read_bool(dev, "microchip,vref-buffered");
380
381 return 0;
382 }
383
mcp4725_probe(struct i2c_client * client)384 static int mcp4725_probe(struct i2c_client *client)
385 {
386 const struct i2c_device_id *id = i2c_client_get_device_id(client);
387 struct mcp4725_data *data;
388 struct iio_dev *indio_dev;
389 struct mcp4725_platform_data *pdata, pdata_dt;
390 u8 inbuf[4];
391 u8 pd;
392 u8 ref;
393 int err;
394
395 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
396 if (indio_dev == NULL)
397 return -ENOMEM;
398 data = iio_priv(indio_dev);
399 i2c_set_clientdata(client, indio_dev);
400 data->client = client;
401 if (dev_fwnode(&client->dev))
402 data->id = (uintptr_t)device_get_match_data(&client->dev);
403 else
404 data->id = id->driver_data;
405 pdata = dev_get_platdata(&client->dev);
406
407 if (!pdata) {
408 err = mcp4725_probe_dt(&client->dev, &pdata_dt);
409 if (err) {
410 dev_err(&client->dev,
411 "invalid platform or devicetree data");
412 return err;
413 }
414 pdata = &pdata_dt;
415 }
416
417 if (data->id == MCP4725 && pdata->use_vref) {
418 dev_err(&client->dev,
419 "external reference is unavailable on MCP4725");
420 return -EINVAL;
421 }
422
423 if (!pdata->use_vref && pdata->vref_buffered) {
424 dev_err(&client->dev,
425 "buffering is unavailable on the internal reference");
426 return -EINVAL;
427 }
428
429 if (!pdata->use_vref)
430 data->ref_mode = MCP472X_REF_VDD;
431 else
432 data->ref_mode = pdata->vref_buffered ?
433 MCP472X_REF_VREF_BUFFERED :
434 MCP472X_REF_VREF_UNBUFFERED;
435
436 data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
437 if (IS_ERR(data->vdd_reg))
438 return PTR_ERR(data->vdd_reg);
439
440 err = regulator_enable(data->vdd_reg);
441 if (err)
442 return err;
443
444 if (pdata->use_vref) {
445 data->vref_reg = devm_regulator_get(&client->dev, "vref");
446 if (IS_ERR(data->vref_reg)) {
447 err = PTR_ERR(data->vref_reg);
448 goto err_disable_vdd_reg;
449 }
450
451 err = regulator_enable(data->vref_reg);
452 if (err)
453 goto err_disable_vdd_reg;
454 }
455
456 indio_dev->name = id->name;
457 indio_dev->info = &mcp4725_info;
458 indio_dev->channels = &mcp472x_channel[id->driver_data];
459 indio_dev->num_channels = 1;
460 indio_dev->modes = INDIO_DIRECT_MODE;
461
462 /* read current DAC value and settings */
463 err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4);
464
465 if (err < 0) {
466 dev_err(&client->dev, "failed to read DAC value");
467 goto err_disable_vref_reg;
468 }
469 pd = (inbuf[0] >> 1) & 0x3;
470 data->powerdown = pd > 0;
471 data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
472 data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
473 if (data->id == MCP4726)
474 ref = (inbuf[3] >> 3) & 0x3;
475
476 if (data->id == MCP4726 && ref != data->ref_mode) {
477 dev_info(&client->dev,
478 "voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
479 data->ref_mode, ref, data->ref_mode);
480 err = mcp4726_set_cfg(indio_dev);
481 if (err < 0)
482 goto err_disable_vref_reg;
483 }
484
485 err = iio_device_register(indio_dev);
486 if (err)
487 goto err_disable_vref_reg;
488
489 return 0;
490
491 err_disable_vref_reg:
492 if (data->vref_reg)
493 regulator_disable(data->vref_reg);
494
495 err_disable_vdd_reg:
496 regulator_disable(data->vdd_reg);
497
498 return err;
499 }
500
mcp4725_remove(struct i2c_client * client)501 static void mcp4725_remove(struct i2c_client *client)
502 {
503 struct iio_dev *indio_dev = i2c_get_clientdata(client);
504 struct mcp4725_data *data = iio_priv(indio_dev);
505
506 iio_device_unregister(indio_dev);
507
508 if (data->vref_reg)
509 regulator_disable(data->vref_reg);
510 regulator_disable(data->vdd_reg);
511 }
512
513 static const struct i2c_device_id mcp4725_id[] = {
514 { "mcp4725", MCP4725 },
515 { "mcp4726", MCP4726 },
516 { }
517 };
518 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
519
520 static const struct of_device_id mcp4725_of_match[] = {
521 {
522 .compatible = "microchip,mcp4725",
523 .data = (void *)MCP4725
524 },
525 {
526 .compatible = "microchip,mcp4726",
527 .data = (void *)MCP4726
528 },
529 { }
530 };
531 MODULE_DEVICE_TABLE(of, mcp4725_of_match);
532
533 static struct i2c_driver mcp4725_driver = {
534 .driver = {
535 .name = MCP4725_DRV_NAME,
536 .of_match_table = mcp4725_of_match,
537 .pm = pm_sleep_ptr(&mcp4725_pm_ops),
538 },
539 .probe = mcp4725_probe,
540 .remove = mcp4725_remove,
541 .id_table = mcp4725_id,
542 };
543 module_i2c_driver(mcp4725_driver);
544
545 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
546 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
547 MODULE_LICENSE("GPL");
548