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
51 outbuf[0] = (data->powerdown_mode + 1) << 4;
52 outbuf[1] = 0;
53 data->powerdown = true;
54
55 return i2c_master_send(data->client, outbuf, 2);
56 }
57
mcp4725_resume(struct device * dev)58 static int mcp4725_resume(struct device *dev)
59 {
60 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
61 to_i2c_client(dev)));
62 u8 outbuf[2];
63
64 /* restore previous DAC value */
65 outbuf[0] = (data->dac_value >> 8) & 0xf;
66 outbuf[1] = data->dac_value & 0xff;
67 data->powerdown = false;
68
69 return i2c_master_send(data->client, outbuf, 2);
70 }
71 static DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend,
72 mcp4725_resume);
73
mcp4725_store_eeprom(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)74 static ssize_t mcp4725_store_eeprom(struct device *dev,
75 struct device_attribute *attr, const char *buf, size_t len)
76 {
77 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
78 struct mcp4725_data *data = iio_priv(indio_dev);
79 int tries = 20;
80 u8 inoutbuf[3];
81 bool state;
82 int ret;
83
84 ret = kstrtobool(buf, &state);
85 if (ret < 0)
86 return ret;
87
88 if (!state)
89 return 0;
90
91 inoutbuf[0] = 0x60; /* write EEPROM */
92 inoutbuf[0] |= data->ref_mode << 3;
93 inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
94 inoutbuf[1] = data->dac_value >> 4;
95 inoutbuf[2] = (data->dac_value & 0xf) << 4;
96
97 ret = i2c_master_send(data->client, inoutbuf, 3);
98 if (ret < 0)
99 return ret;
100 else if (ret != 3)
101 return -EIO;
102
103 /* wait for write complete, takes up to 50ms */
104 while (tries--) {
105 msleep(20);
106 ret = i2c_master_recv(data->client, inoutbuf, 3);
107 if (ret < 0)
108 return ret;
109 else if (ret != 3)
110 return -EIO;
111
112 if (inoutbuf[0] & 0x80)
113 break;
114 }
115
116 if (tries < 0) {
117 dev_err(&data->client->dev,
118 "mcp4725_store_eeprom() failed, incomplete\n");
119 return -EIO;
120 }
121
122 return len;
123 }
124
125 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
126
127 static struct attribute *mcp4725_attributes[] = {
128 &iio_dev_attr_store_eeprom.dev_attr.attr,
129 NULL,
130 };
131
132 static const struct attribute_group mcp4725_attribute_group = {
133 .attrs = mcp4725_attributes,
134 };
135
136 static const char * const mcp4725_powerdown_modes[] = {
137 "1kohm_to_gnd",
138 "100kohm_to_gnd",
139 "500kohm_to_gnd"
140 };
141
142 static const char * const mcp4726_powerdown_modes[] = {
143 "1kohm_to_gnd",
144 "125kohm_to_gnd",
145 "640kohm_to_gnd"
146 };
147
mcp4725_get_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan)148 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
149 const struct iio_chan_spec *chan)
150 {
151 struct mcp4725_data *data = iio_priv(indio_dev);
152
153 return data->powerdown_mode;
154 }
155
mcp4725_set_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,unsigned mode)156 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
157 const struct iio_chan_spec *chan, unsigned mode)
158 {
159 struct mcp4725_data *data = iio_priv(indio_dev);
160
161 data->powerdown_mode = mode;
162
163 return 0;
164 }
165
mcp4725_read_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)166 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
167 uintptr_t private, const struct iio_chan_spec *chan, char *buf)
168 {
169 struct mcp4725_data *data = iio_priv(indio_dev);
170
171 return sysfs_emit(buf, "%d\n", data->powerdown);
172 }
173
mcp4725_write_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)174 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
175 uintptr_t private, const struct iio_chan_spec *chan,
176 const char *buf, size_t len)
177 {
178 struct mcp4725_data *data = iio_priv(indio_dev);
179 bool state;
180 int ret;
181
182 ret = kstrtobool(buf, &state);
183 if (ret)
184 return ret;
185
186 if (state)
187 ret = mcp4725_suspend(&data->client->dev);
188 else
189 ret = mcp4725_resume(&data->client->dev);
190 if (ret < 0)
191 return ret;
192
193 return len;
194 }
195
196 enum chip_id {
197 MCP4725,
198 MCP4726,
199 };
200
201 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
202 [MCP4725] = {
203 .items = mcp4725_powerdown_modes,
204 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
205 .get = mcp4725_get_powerdown_mode,
206 .set = mcp4725_set_powerdown_mode,
207 },
208 [MCP4726] = {
209 .items = mcp4726_powerdown_modes,
210 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
211 .get = mcp4725_get_powerdown_mode,
212 .set = mcp4725_set_powerdown_mode,
213 },
214 };
215
216 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
217 {
218 .name = "powerdown",
219 .read = mcp4725_read_powerdown,
220 .write = mcp4725_write_powerdown,
221 .shared = IIO_SEPARATE,
222 },
223 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
224 &mcp472x_powerdown_mode_enum[MCP4725]),
225 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
226 &mcp472x_powerdown_mode_enum[MCP4725]),
227 { },
228 };
229
230 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
231 {
232 .name = "powerdown",
233 .read = mcp4725_read_powerdown,
234 .write = mcp4725_write_powerdown,
235 .shared = IIO_SEPARATE,
236 },
237 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
238 &mcp472x_powerdown_mode_enum[MCP4726]),
239 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
240 &mcp472x_powerdown_mode_enum[MCP4726]),
241 { },
242 };
243
244 static const struct iio_chan_spec mcp472x_channel[] = {
245 [MCP4725] = {
246 .type = IIO_VOLTAGE,
247 .indexed = 1,
248 .output = 1,
249 .channel = 0,
250 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
251 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
252 .ext_info = mcp4725_ext_info,
253 },
254 [MCP4726] = {
255 .type = IIO_VOLTAGE,
256 .indexed = 1,
257 .output = 1,
258 .channel = 0,
259 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
260 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
261 .ext_info = mcp4726_ext_info,
262 },
263 };
264
mcp4725_set_value(struct iio_dev * indio_dev,int val)265 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
266 {
267 struct mcp4725_data *data = iio_priv(indio_dev);
268 u8 outbuf[2];
269 int ret;
270
271 if (val >= (1 << 12) || val < 0)
272 return -EINVAL;
273
274 outbuf[0] = (val >> 8) & 0xf;
275 outbuf[1] = val & 0xff;
276
277 ret = i2c_master_send(data->client, outbuf, 2);
278 if (ret < 0)
279 return ret;
280 else if (ret != 2)
281 return -EIO;
282 else
283 return 0;
284 }
285
mcp4726_set_cfg(struct iio_dev * indio_dev)286 static int mcp4726_set_cfg(struct iio_dev *indio_dev)
287 {
288 struct mcp4725_data *data = iio_priv(indio_dev);
289 u8 outbuf[3];
290 int ret;
291
292 outbuf[0] = 0x40;
293 outbuf[0] |= data->ref_mode << 3;
294 if (data->powerdown)
295 outbuf[0] |= data->powerdown << 1;
296 outbuf[1] = data->dac_value >> 4;
297 outbuf[2] = (data->dac_value & 0xf) << 4;
298
299 ret = i2c_master_send(data->client, outbuf, 3);
300 if (ret < 0)
301 return ret;
302 else if (ret != 3)
303 return -EIO;
304 else
305 return 0;
306 }
307
mcp4725_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)308 static int mcp4725_read_raw(struct iio_dev *indio_dev,
309 struct iio_chan_spec const *chan,
310 int *val, int *val2, long mask)
311 {
312 struct mcp4725_data *data = iio_priv(indio_dev);
313 int ret;
314
315 switch (mask) {
316 case IIO_CHAN_INFO_RAW:
317 *val = data->dac_value;
318 return IIO_VAL_INT;
319 case IIO_CHAN_INFO_SCALE:
320 if (data->ref_mode == MCP472X_REF_VDD)
321 ret = regulator_get_voltage(data->vdd_reg);
322 else
323 ret = regulator_get_voltage(data->vref_reg);
324
325 if (ret < 0)
326 return ret;
327
328 *val = ret / 1000;
329 *val2 = 12;
330 return IIO_VAL_FRACTIONAL_LOG2;
331 }
332 return -EINVAL;
333 }
334
mcp4725_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)335 static int mcp4725_write_raw(struct iio_dev *indio_dev,
336 struct iio_chan_spec const *chan,
337 int val, int val2, long mask)
338 {
339 struct mcp4725_data *data = iio_priv(indio_dev);
340 int ret;
341
342 switch (mask) {
343 case IIO_CHAN_INFO_RAW:
344 ret = mcp4725_set_value(indio_dev, val);
345 data->dac_value = val;
346 break;
347 default:
348 ret = -EINVAL;
349 break;
350 }
351
352 return ret;
353 }
354
355 static const struct iio_info mcp4725_info = {
356 .read_raw = mcp4725_read_raw,
357 .write_raw = mcp4725_write_raw,
358 .attrs = &mcp4725_attribute_group,
359 };
360
mcp4725_probe_dt(struct device * dev,struct mcp4725_platform_data * pdata)361 static int mcp4725_probe_dt(struct device *dev,
362 struct mcp4725_platform_data *pdata)
363 {
364 /* check if is the vref-supply defined */
365 pdata->use_vref = device_property_read_bool(dev, "vref-supply");
366 pdata->vref_buffered =
367 device_property_read_bool(dev, "microchip,vref-buffered");
368
369 return 0;
370 }
371
mcp4725_probe(struct i2c_client * client)372 static int mcp4725_probe(struct i2c_client *client)
373 {
374 const struct i2c_device_id *id = i2c_client_get_device_id(client);
375 struct mcp4725_data *data;
376 struct iio_dev *indio_dev;
377 struct mcp4725_platform_data *pdata, pdata_dt;
378 u8 inbuf[4];
379 u8 pd;
380 u8 ref;
381 int err;
382
383 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
384 if (indio_dev == NULL)
385 return -ENOMEM;
386 data = iio_priv(indio_dev);
387 i2c_set_clientdata(client, indio_dev);
388 data->client = client;
389 if (dev_fwnode(&client->dev))
390 data->id = (uintptr_t)device_get_match_data(&client->dev);
391 else
392 data->id = id->driver_data;
393 pdata = dev_get_platdata(&client->dev);
394
395 if (!pdata) {
396 err = mcp4725_probe_dt(&client->dev, &pdata_dt);
397 if (err) {
398 dev_err(&client->dev,
399 "invalid platform or devicetree data");
400 return err;
401 }
402 pdata = &pdata_dt;
403 }
404
405 if (data->id == MCP4725 && pdata->use_vref) {
406 dev_err(&client->dev,
407 "external reference is unavailable on MCP4725");
408 return -EINVAL;
409 }
410
411 if (!pdata->use_vref && pdata->vref_buffered) {
412 dev_err(&client->dev,
413 "buffering is unavailable on the internal reference");
414 return -EINVAL;
415 }
416
417 if (!pdata->use_vref)
418 data->ref_mode = MCP472X_REF_VDD;
419 else
420 data->ref_mode = pdata->vref_buffered ?
421 MCP472X_REF_VREF_BUFFERED :
422 MCP472X_REF_VREF_UNBUFFERED;
423
424 data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
425 if (IS_ERR(data->vdd_reg))
426 return PTR_ERR(data->vdd_reg);
427
428 err = regulator_enable(data->vdd_reg);
429 if (err)
430 return err;
431
432 if (pdata->use_vref) {
433 data->vref_reg = devm_regulator_get(&client->dev, "vref");
434 if (IS_ERR(data->vref_reg)) {
435 err = PTR_ERR(data->vref_reg);
436 goto err_disable_vdd_reg;
437 }
438
439 err = regulator_enable(data->vref_reg);
440 if (err)
441 goto err_disable_vdd_reg;
442 }
443
444 indio_dev->name = id->name;
445 indio_dev->info = &mcp4725_info;
446 indio_dev->channels = &mcp472x_channel[id->driver_data];
447 indio_dev->num_channels = 1;
448 indio_dev->modes = INDIO_DIRECT_MODE;
449
450 /* read current DAC value and settings */
451 err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4);
452
453 if (err < 0) {
454 dev_err(&client->dev, "failed to read DAC value");
455 goto err_disable_vref_reg;
456 }
457 pd = (inbuf[0] >> 1) & 0x3;
458 data->powerdown = pd > 0;
459 data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
460 data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
461 if (data->id == MCP4726)
462 ref = (inbuf[3] >> 3) & 0x3;
463
464 if (data->id == MCP4726 && ref != data->ref_mode) {
465 dev_info(&client->dev,
466 "voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
467 data->ref_mode, ref, data->ref_mode);
468 err = mcp4726_set_cfg(indio_dev);
469 if (err < 0)
470 goto err_disable_vref_reg;
471 }
472
473 err = iio_device_register(indio_dev);
474 if (err)
475 goto err_disable_vref_reg;
476
477 return 0;
478
479 err_disable_vref_reg:
480 if (data->vref_reg)
481 regulator_disable(data->vref_reg);
482
483 err_disable_vdd_reg:
484 regulator_disable(data->vdd_reg);
485
486 return err;
487 }
488
mcp4725_remove(struct i2c_client * client)489 static void mcp4725_remove(struct i2c_client *client)
490 {
491 struct iio_dev *indio_dev = i2c_get_clientdata(client);
492 struct mcp4725_data *data = iio_priv(indio_dev);
493
494 iio_device_unregister(indio_dev);
495
496 if (data->vref_reg)
497 regulator_disable(data->vref_reg);
498 regulator_disable(data->vdd_reg);
499 }
500
501 static const struct i2c_device_id mcp4725_id[] = {
502 { "mcp4725", MCP4725 },
503 { "mcp4726", MCP4726 },
504 { }
505 };
506 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
507
508 static const struct of_device_id mcp4725_of_match[] = {
509 {
510 .compatible = "microchip,mcp4725",
511 .data = (void *)MCP4725
512 },
513 {
514 .compatible = "microchip,mcp4726",
515 .data = (void *)MCP4726
516 },
517 { }
518 };
519 MODULE_DEVICE_TABLE(of, mcp4725_of_match);
520
521 static struct i2c_driver mcp4725_driver = {
522 .driver = {
523 .name = MCP4725_DRV_NAME,
524 .of_match_table = mcp4725_of_match,
525 .pm = pm_sleep_ptr(&mcp4725_pm_ops),
526 },
527 .probe_new = mcp4725_probe,
528 .remove = mcp4725_remove,
529 .id_table = mcp4725_id,
530 };
531 module_i2c_driver(mcp4725_driver);
532
533 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
534 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
535 MODULE_LICENSE("GPL");
536