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/property.h>
20
21 #include <linux/iio/iio.h>
22 #include <linux/iio/sysfs.h>
23
24 #include <linux/iio/dac/mcp4725.h>
25
26 #define MCP472X_REF_VDD 0x00
27 #define MCP472X_REF_VREF_UNBUFFERED 0x02
28 #define MCP472X_REF_VREF_BUFFERED 0x03
29
30 struct mcp4725_chip_info {
31 const struct iio_chan_spec *chan_spec;
32 u8 dac_reg_offset;
33 bool use_ext_ref_voltage;
34 };
35
36 struct mcp4725_data {
37 struct i2c_client *client;
38 unsigned ref_mode;
39 bool vref_buffered;
40 u16 dac_value;
41 bool powerdown;
42 unsigned powerdown_mode;
43 struct regulator *vdd_reg;
44 struct regulator *vref_reg;
45 };
46
mcp4725_suspend(struct device * dev)47 static int mcp4725_suspend(struct device *dev)
48 {
49 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
50 to_i2c_client(dev)));
51 u8 outbuf[2];
52 int ret;
53
54 outbuf[0] = (data->powerdown_mode + 1) << 4;
55 outbuf[1] = 0;
56 data->powerdown = true;
57
58 ret = i2c_master_send(data->client, outbuf, 2);
59 if (ret < 0)
60 return ret;
61 else if (ret != 2)
62 return -EIO;
63 return 0;
64 }
65
mcp4725_resume(struct device * dev)66 static int mcp4725_resume(struct device *dev)
67 {
68 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
69 to_i2c_client(dev)));
70 u8 outbuf[2];
71 int ret;
72
73 /* restore previous DAC value */
74 outbuf[0] = (data->dac_value >> 8) & 0xf;
75 outbuf[1] = data->dac_value & 0xff;
76 data->powerdown = false;
77
78 ret = i2c_master_send(data->client, outbuf, 2);
79 if (ret < 0)
80 return ret;
81 else if (ret != 2)
82 return -EIO;
83 return 0;
84 }
85 static DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend,
86 mcp4725_resume);
87
mcp4725_store_eeprom(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)88 static ssize_t mcp4725_store_eeprom(struct device *dev,
89 struct device_attribute *attr, const char *buf, size_t len)
90 {
91 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
92 struct mcp4725_data *data = iio_priv(indio_dev);
93 int tries = 20;
94 u8 inoutbuf[3];
95 bool state;
96 int ret;
97
98 ret = kstrtobool(buf, &state);
99 if (ret < 0)
100 return ret;
101
102 if (!state)
103 return 0;
104
105 inoutbuf[0] = 0x60; /* write EEPROM */
106 inoutbuf[0] |= data->ref_mode << 3;
107 inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
108 inoutbuf[1] = data->dac_value >> 4;
109 inoutbuf[2] = (data->dac_value & 0xf) << 4;
110
111 ret = i2c_master_send(data->client, inoutbuf, 3);
112 if (ret < 0)
113 return ret;
114 else if (ret != 3)
115 return -EIO;
116
117 /* wait for write complete, takes up to 50ms */
118 while (tries--) {
119 msleep(20);
120 ret = i2c_master_recv(data->client, inoutbuf, 3);
121 if (ret < 0)
122 return ret;
123 else if (ret != 3)
124 return -EIO;
125
126 if (inoutbuf[0] & 0x80)
127 break;
128 }
129
130 if (tries < 0) {
131 dev_err(&data->client->dev,
132 "mcp4725_store_eeprom() failed, incomplete\n");
133 return -EIO;
134 }
135
136 return len;
137 }
138
139 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
140
141 static struct attribute *mcp4725_attributes[] = {
142 &iio_dev_attr_store_eeprom.dev_attr.attr,
143 NULL,
144 };
145
146 static const struct attribute_group mcp4725_attribute_group = {
147 .attrs = mcp4725_attributes,
148 };
149
150 static const char * const mcp4725_powerdown_modes[] = {
151 "1kohm_to_gnd",
152 "100kohm_to_gnd",
153 "500kohm_to_gnd"
154 };
155
156 static const char * const mcp4726_powerdown_modes[] = {
157 "1kohm_to_gnd",
158 "125kohm_to_gnd",
159 "640kohm_to_gnd"
160 };
161
mcp4725_get_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan)162 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
163 const struct iio_chan_spec *chan)
164 {
165 struct mcp4725_data *data = iio_priv(indio_dev);
166
167 return data->powerdown_mode;
168 }
169
mcp4725_set_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,unsigned mode)170 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
171 const struct iio_chan_spec *chan, unsigned mode)
172 {
173 struct mcp4725_data *data = iio_priv(indio_dev);
174
175 data->powerdown_mode = mode;
176
177 return 0;
178 }
179
mcp4725_read_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)180 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
181 uintptr_t private, const struct iio_chan_spec *chan, char *buf)
182 {
183 struct mcp4725_data *data = iio_priv(indio_dev);
184
185 return sysfs_emit(buf, "%d\n", data->powerdown);
186 }
187
mcp4725_write_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)188 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
189 uintptr_t private, const struct iio_chan_spec *chan,
190 const char *buf, size_t len)
191 {
192 struct mcp4725_data *data = iio_priv(indio_dev);
193 bool state;
194 int ret;
195
196 ret = kstrtobool(buf, &state);
197 if (ret)
198 return ret;
199
200 if (state)
201 ret = mcp4725_suspend(&data->client->dev);
202 else
203 ret = mcp4725_resume(&data->client->dev);
204 if (ret < 0)
205 return ret;
206
207 return len;
208 }
209
210 enum chip_id {
211 MCP4725,
212 MCP4726,
213 };
214
215 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
216 [MCP4725] = {
217 .items = mcp4725_powerdown_modes,
218 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
219 .get = mcp4725_get_powerdown_mode,
220 .set = mcp4725_set_powerdown_mode,
221 },
222 [MCP4726] = {
223 .items = mcp4726_powerdown_modes,
224 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
225 .get = mcp4725_get_powerdown_mode,
226 .set = mcp4725_set_powerdown_mode,
227 },
228 };
229
230 static const struct iio_chan_spec_ext_info mcp4725_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[MCP4725]),
239 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
240 &mcp472x_powerdown_mode_enum[MCP4725]),
241 { }
242 };
243
244 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
245 {
246 .name = "powerdown",
247 .read = mcp4725_read_powerdown,
248 .write = mcp4725_write_powerdown,
249 .shared = IIO_SEPARATE,
250 },
251 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
252 &mcp472x_powerdown_mode_enum[MCP4726]),
253 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
254 &mcp472x_powerdown_mode_enum[MCP4726]),
255 { }
256 };
257
258 static const struct iio_chan_spec mcp472x_channel[] = {
259 [MCP4725] = {
260 .type = IIO_VOLTAGE,
261 .indexed = 1,
262 .output = 1,
263 .channel = 0,
264 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
265 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
266 .ext_info = mcp4725_ext_info,
267 },
268 [MCP4726] = {
269 .type = IIO_VOLTAGE,
270 .indexed = 1,
271 .output = 1,
272 .channel = 0,
273 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
274 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
275 .ext_info = mcp4726_ext_info,
276 },
277 };
278
mcp4725_set_value(struct iio_dev * indio_dev,int val)279 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
280 {
281 struct mcp4725_data *data = iio_priv(indio_dev);
282 u8 outbuf[2];
283 int ret;
284
285 if (val >= (1 << 12) || val < 0)
286 return -EINVAL;
287
288 outbuf[0] = (val >> 8) & 0xf;
289 outbuf[1] = val & 0xff;
290
291 ret = i2c_master_send(data->client, outbuf, 2);
292 if (ret < 0)
293 return ret;
294 else if (ret != 2)
295 return -EIO;
296 else
297 return 0;
298 }
299
mcp4726_set_cfg(struct iio_dev * indio_dev)300 static int mcp4726_set_cfg(struct iio_dev *indio_dev)
301 {
302 struct mcp4725_data *data = iio_priv(indio_dev);
303 u8 outbuf[3];
304 int ret;
305
306 outbuf[0] = 0x40;
307 outbuf[0] |= data->ref_mode << 3;
308 if (data->powerdown)
309 outbuf[0] |= data->powerdown << 1;
310 outbuf[1] = data->dac_value >> 4;
311 outbuf[2] = (data->dac_value & 0xf) << 4;
312
313 ret = i2c_master_send(data->client, outbuf, 3);
314 if (ret < 0)
315 return ret;
316 else if (ret != 3)
317 return -EIO;
318 else
319 return 0;
320 }
321
mcp4725_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)322 static int mcp4725_read_raw(struct iio_dev *indio_dev,
323 struct iio_chan_spec const *chan,
324 int *val, int *val2, long mask)
325 {
326 struct mcp4725_data *data = iio_priv(indio_dev);
327 int ret;
328
329 switch (mask) {
330 case IIO_CHAN_INFO_RAW:
331 *val = data->dac_value;
332 return IIO_VAL_INT;
333 case IIO_CHAN_INFO_SCALE:
334 if (data->ref_mode == MCP472X_REF_VDD)
335 ret = regulator_get_voltage(data->vdd_reg);
336 else
337 ret = regulator_get_voltage(data->vref_reg);
338
339 if (ret < 0)
340 return ret;
341
342 *val = ret / 1000;
343 *val2 = 12;
344 return IIO_VAL_FRACTIONAL_LOG2;
345 }
346 return -EINVAL;
347 }
348
mcp4725_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)349 static int mcp4725_write_raw(struct iio_dev *indio_dev,
350 struct iio_chan_spec const *chan,
351 int val, int val2, long mask)
352 {
353 struct mcp4725_data *data = iio_priv(indio_dev);
354 int ret;
355
356 switch (mask) {
357 case IIO_CHAN_INFO_RAW:
358 ret = mcp4725_set_value(indio_dev, val);
359 data->dac_value = val;
360 break;
361 default:
362 ret = -EINVAL;
363 break;
364 }
365
366 return ret;
367 }
368
369 static const struct iio_info mcp4725_info = {
370 .read_raw = mcp4725_read_raw,
371 .write_raw = mcp4725_write_raw,
372 .attrs = &mcp4725_attribute_group,
373 };
374
mcp4725_probe_dt(struct device * dev,struct mcp4725_platform_data * pdata)375 static int mcp4725_probe_dt(struct device *dev,
376 struct mcp4725_platform_data *pdata)
377 {
378 /* check if is the vref-supply defined */
379 pdata->use_vref = device_property_present(dev, "vref-supply");
380 pdata->vref_buffered =
381 device_property_read_bool(dev, "microchip,vref-buffered");
382
383 return 0;
384 }
385
mcp4725_probe(struct i2c_client * client)386 static int mcp4725_probe(struct i2c_client *client)
387 {
388 const struct i2c_device_id *id = i2c_client_get_device_id(client);
389 const struct mcp4725_chip_info *info;
390 struct mcp4725_data *data;
391 struct iio_dev *indio_dev;
392 struct mcp4725_platform_data *pdata, pdata_dt;
393 u8 inbuf[4];
394 u8 pd;
395 u8 ref;
396 int err;
397
398 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
399 if (indio_dev == NULL)
400 return -ENOMEM;
401 data = iio_priv(indio_dev);
402 i2c_set_clientdata(client, indio_dev);
403 data->client = client;
404 info = i2c_get_match_data(client);
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 (info->use_ext_ref_voltage && 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 = info->chan_spec;
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, info->dac_reg_offset);
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 (!info->use_ext_ref_voltage)
474 ref = (inbuf[3] >> 3) & 0x3;
475
476 if (!info->use_ext_ref_voltage && 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 mcp4725_chip_info mcp4725 = {
514 .chan_spec = &mcp472x_channel[MCP4725],
515 .dac_reg_offset = 3,
516 .use_ext_ref_voltage = true,
517 };
518
519 static const struct mcp4725_chip_info mcp4726 = {
520 .chan_spec = &mcp472x_channel[MCP4726],
521 .dac_reg_offset = 4,
522 };
523
524 static const struct i2c_device_id mcp4725_id[] = {
525 { .name = "mcp4725", .driver_data = (kernel_ulong_t)&mcp4725 },
526 { .name = "mcp4726", .driver_data = (kernel_ulong_t)&mcp4726 },
527 { }
528 };
529 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
530
531 static const struct of_device_id mcp4725_of_match[] = {
532 {
533 .compatible = "microchip,mcp4725",
534 .data = &mcp4725
535 },
536 {
537 .compatible = "microchip,mcp4726",
538 .data = &mcp4726
539 },
540 { }
541 };
542 MODULE_DEVICE_TABLE(of, mcp4725_of_match);
543
544 static struct i2c_driver mcp4725_driver = {
545 .driver = {
546 .name = "mcp4725",
547 .of_match_table = mcp4725_of_match,
548 .pm = pm_sleep_ptr(&mcp4725_pm_ops),
549 },
550 .probe = mcp4725_probe,
551 .remove = mcp4725_remove,
552 .id_table = mcp4725_id,
553 };
554 module_i2c_driver(mcp4725_driver);
555
556 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
557 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
558 MODULE_LICENSE("GPL");
559