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 MCP472X_REF_VDD 0x00
28 #define MCP472X_REF_VREF_UNBUFFERED 0x02
29 #define MCP472X_REF_VREF_BUFFERED 0x03
30
31 struct mcp4725_chip_info {
32 const struct iio_chan_spec *chan_spec;
33 u8 dac_reg_offset;
34 bool use_ext_ref_voltage;
35 };
36
37 struct mcp4725_data {
38 struct i2c_client *client;
39 unsigned ref_mode;
40 bool vref_buffered;
41 u16 dac_value;
42 bool powerdown;
43 unsigned powerdown_mode;
44 struct regulator *vdd_reg;
45 struct regulator *vref_reg;
46 };
47
mcp4725_suspend(struct device * dev)48 static int mcp4725_suspend(struct device *dev)
49 {
50 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
51 to_i2c_client(dev)));
52 u8 outbuf[2];
53 int ret;
54
55 outbuf[0] = (data->powerdown_mode + 1) << 4;
56 outbuf[1] = 0;
57 data->powerdown = true;
58
59 ret = i2c_master_send(data->client, outbuf, 2);
60 if (ret < 0)
61 return ret;
62 else if (ret != 2)
63 return -EIO;
64 return 0;
65 }
66
mcp4725_resume(struct device * dev)67 static int mcp4725_resume(struct device *dev)
68 {
69 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
70 to_i2c_client(dev)));
71 u8 outbuf[2];
72 int ret;
73
74 /* restore previous DAC value */
75 outbuf[0] = (data->dac_value >> 8) & 0xf;
76 outbuf[1] = data->dac_value & 0xff;
77 data->powerdown = false;
78
79 ret = i2c_master_send(data->client, outbuf, 2);
80 if (ret < 0)
81 return ret;
82 else if (ret != 2)
83 return -EIO;
84 return 0;
85 }
86 static DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend,
87 mcp4725_resume);
88
mcp4725_store_eeprom(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)89 static ssize_t mcp4725_store_eeprom(struct device *dev,
90 struct device_attribute *attr, const char *buf, size_t len)
91 {
92 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
93 struct mcp4725_data *data = iio_priv(indio_dev);
94 int tries = 20;
95 u8 inoutbuf[3];
96 bool state;
97 int ret;
98
99 ret = kstrtobool(buf, &state);
100 if (ret < 0)
101 return ret;
102
103 if (!state)
104 return 0;
105
106 inoutbuf[0] = 0x60; /* write EEPROM */
107 inoutbuf[0] |= data->ref_mode << 3;
108 inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
109 inoutbuf[1] = data->dac_value >> 4;
110 inoutbuf[2] = (data->dac_value & 0xf) << 4;
111
112 ret = i2c_master_send(data->client, inoutbuf, 3);
113 if (ret < 0)
114 return ret;
115 else if (ret != 3)
116 return -EIO;
117
118 /* wait for write complete, takes up to 50ms */
119 while (tries--) {
120 msleep(20);
121 ret = i2c_master_recv(data->client, inoutbuf, 3);
122 if (ret < 0)
123 return ret;
124 else if (ret != 3)
125 return -EIO;
126
127 if (inoutbuf[0] & 0x80)
128 break;
129 }
130
131 if (tries < 0) {
132 dev_err(&data->client->dev,
133 "mcp4725_store_eeprom() failed, incomplete\n");
134 return -EIO;
135 }
136
137 return len;
138 }
139
140 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
141
142 static struct attribute *mcp4725_attributes[] = {
143 &iio_dev_attr_store_eeprom.dev_attr.attr,
144 NULL,
145 };
146
147 static const struct attribute_group mcp4725_attribute_group = {
148 .attrs = mcp4725_attributes,
149 };
150
151 static const char * const mcp4725_powerdown_modes[] = {
152 "1kohm_to_gnd",
153 "100kohm_to_gnd",
154 "500kohm_to_gnd"
155 };
156
157 static const char * const mcp4726_powerdown_modes[] = {
158 "1kohm_to_gnd",
159 "125kohm_to_gnd",
160 "640kohm_to_gnd"
161 };
162
mcp4725_get_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan)163 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
164 const struct iio_chan_spec *chan)
165 {
166 struct mcp4725_data *data = iio_priv(indio_dev);
167
168 return data->powerdown_mode;
169 }
170
mcp4725_set_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,unsigned mode)171 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
172 const struct iio_chan_spec *chan, unsigned mode)
173 {
174 struct mcp4725_data *data = iio_priv(indio_dev);
175
176 data->powerdown_mode = mode;
177
178 return 0;
179 }
180
mcp4725_read_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)181 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
182 uintptr_t private, const struct iio_chan_spec *chan, char *buf)
183 {
184 struct mcp4725_data *data = iio_priv(indio_dev);
185
186 return sysfs_emit(buf, "%d\n", data->powerdown);
187 }
188
mcp4725_write_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)189 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
190 uintptr_t private, const struct iio_chan_spec *chan,
191 const char *buf, size_t len)
192 {
193 struct mcp4725_data *data = iio_priv(indio_dev);
194 bool state;
195 int ret;
196
197 ret = kstrtobool(buf, &state);
198 if (ret)
199 return ret;
200
201 if (state)
202 ret = mcp4725_suspend(&data->client->dev);
203 else
204 ret = mcp4725_resume(&data->client->dev);
205 if (ret < 0)
206 return ret;
207
208 return len;
209 }
210
211 enum chip_id {
212 MCP4725,
213 MCP4726,
214 };
215
216 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
217 [MCP4725] = {
218 .items = mcp4725_powerdown_modes,
219 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
220 .get = mcp4725_get_powerdown_mode,
221 .set = mcp4725_set_powerdown_mode,
222 },
223 [MCP4726] = {
224 .items = mcp4726_powerdown_modes,
225 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
226 .get = mcp4725_get_powerdown_mode,
227 .set = mcp4725_set_powerdown_mode,
228 },
229 };
230
231 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
232 {
233 .name = "powerdown",
234 .read = mcp4725_read_powerdown,
235 .write = mcp4725_write_powerdown,
236 .shared = IIO_SEPARATE,
237 },
238 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
239 &mcp472x_powerdown_mode_enum[MCP4725]),
240 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
241 &mcp472x_powerdown_mode_enum[MCP4725]),
242 { }
243 };
244
245 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
246 {
247 .name = "powerdown",
248 .read = mcp4725_read_powerdown,
249 .write = mcp4725_write_powerdown,
250 .shared = IIO_SEPARATE,
251 },
252 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
253 &mcp472x_powerdown_mode_enum[MCP4726]),
254 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
255 &mcp472x_powerdown_mode_enum[MCP4726]),
256 { }
257 };
258
259 static const struct iio_chan_spec mcp472x_channel[] = {
260 [MCP4725] = {
261 .type = IIO_VOLTAGE,
262 .indexed = 1,
263 .output = 1,
264 .channel = 0,
265 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
266 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
267 .ext_info = mcp4725_ext_info,
268 },
269 [MCP4726] = {
270 .type = IIO_VOLTAGE,
271 .indexed = 1,
272 .output = 1,
273 .channel = 0,
274 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
275 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
276 .ext_info = mcp4726_ext_info,
277 },
278 };
279
mcp4725_set_value(struct iio_dev * indio_dev,int val)280 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
281 {
282 struct mcp4725_data *data = iio_priv(indio_dev);
283 u8 outbuf[2];
284 int ret;
285
286 if (val >= (1 << 12) || val < 0)
287 return -EINVAL;
288
289 outbuf[0] = (val >> 8) & 0xf;
290 outbuf[1] = val & 0xff;
291
292 ret = i2c_master_send(data->client, outbuf, 2);
293 if (ret < 0)
294 return ret;
295 else if (ret != 2)
296 return -EIO;
297 else
298 return 0;
299 }
300
mcp4726_set_cfg(struct iio_dev * indio_dev)301 static int mcp4726_set_cfg(struct iio_dev *indio_dev)
302 {
303 struct mcp4725_data *data = iio_priv(indio_dev);
304 u8 outbuf[3];
305 int ret;
306
307 outbuf[0] = 0x40;
308 outbuf[0] |= data->ref_mode << 3;
309 if (data->powerdown)
310 outbuf[0] |= data->powerdown << 1;
311 outbuf[1] = data->dac_value >> 4;
312 outbuf[2] = (data->dac_value & 0xf) << 4;
313
314 ret = i2c_master_send(data->client, outbuf, 3);
315 if (ret < 0)
316 return ret;
317 else if (ret != 3)
318 return -EIO;
319 else
320 return 0;
321 }
322
mcp4725_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)323 static int mcp4725_read_raw(struct iio_dev *indio_dev,
324 struct iio_chan_spec const *chan,
325 int *val, int *val2, long mask)
326 {
327 struct mcp4725_data *data = iio_priv(indio_dev);
328 int ret;
329
330 switch (mask) {
331 case IIO_CHAN_INFO_RAW:
332 *val = data->dac_value;
333 return IIO_VAL_INT;
334 case IIO_CHAN_INFO_SCALE:
335 if (data->ref_mode == MCP472X_REF_VDD)
336 ret = regulator_get_voltage(data->vdd_reg);
337 else
338 ret = regulator_get_voltage(data->vref_reg);
339
340 if (ret < 0)
341 return ret;
342
343 *val = ret / 1000;
344 *val2 = 12;
345 return IIO_VAL_FRACTIONAL_LOG2;
346 }
347 return -EINVAL;
348 }
349
mcp4725_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)350 static int mcp4725_write_raw(struct iio_dev *indio_dev,
351 struct iio_chan_spec const *chan,
352 int val, int val2, long mask)
353 {
354 struct mcp4725_data *data = iio_priv(indio_dev);
355 int ret;
356
357 switch (mask) {
358 case IIO_CHAN_INFO_RAW:
359 ret = mcp4725_set_value(indio_dev, val);
360 data->dac_value = val;
361 break;
362 default:
363 ret = -EINVAL;
364 break;
365 }
366
367 return ret;
368 }
369
370 static const struct iio_info mcp4725_info = {
371 .read_raw = mcp4725_read_raw,
372 .write_raw = mcp4725_write_raw,
373 .attrs = &mcp4725_attribute_group,
374 };
375
mcp4725_probe_dt(struct device * dev,struct mcp4725_platform_data * pdata)376 static int mcp4725_probe_dt(struct device *dev,
377 struct mcp4725_platform_data *pdata)
378 {
379 /* check if is the vref-supply defined */
380 pdata->use_vref = device_property_present(dev, "vref-supply");
381 pdata->vref_buffered =
382 device_property_read_bool(dev, "microchip,vref-buffered");
383
384 return 0;
385 }
386
mcp4725_probe(struct i2c_client * client)387 static int mcp4725_probe(struct i2c_client *client)
388 {
389 const struct i2c_device_id *id = i2c_client_get_device_id(client);
390 const struct mcp4725_chip_info *info;
391 struct mcp4725_data *data;
392 struct iio_dev *indio_dev;
393 struct mcp4725_platform_data *pdata, pdata_dt;
394 u8 inbuf[4];
395 u8 pd;
396 u8 ref;
397 int err;
398
399 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
400 if (indio_dev == NULL)
401 return -ENOMEM;
402 data = iio_priv(indio_dev);
403 i2c_set_clientdata(client, indio_dev);
404 data->client = client;
405 info = i2c_get_match_data(client);
406 pdata = dev_get_platdata(&client->dev);
407
408 if (!pdata) {
409 err = mcp4725_probe_dt(&client->dev, &pdata_dt);
410 if (err) {
411 dev_err(&client->dev,
412 "invalid platform or devicetree data");
413 return err;
414 }
415 pdata = &pdata_dt;
416 }
417
418 if (info->use_ext_ref_voltage && pdata->use_vref) {
419 dev_err(&client->dev,
420 "external reference is unavailable on MCP4725");
421 return -EINVAL;
422 }
423
424 if (!pdata->use_vref && pdata->vref_buffered) {
425 dev_err(&client->dev,
426 "buffering is unavailable on the internal reference");
427 return -EINVAL;
428 }
429
430 if (!pdata->use_vref)
431 data->ref_mode = MCP472X_REF_VDD;
432 else
433 data->ref_mode = pdata->vref_buffered ?
434 MCP472X_REF_VREF_BUFFERED :
435 MCP472X_REF_VREF_UNBUFFERED;
436
437 data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
438 if (IS_ERR(data->vdd_reg))
439 return PTR_ERR(data->vdd_reg);
440
441 err = regulator_enable(data->vdd_reg);
442 if (err)
443 return err;
444
445 if (pdata->use_vref) {
446 data->vref_reg = devm_regulator_get(&client->dev, "vref");
447 if (IS_ERR(data->vref_reg)) {
448 err = PTR_ERR(data->vref_reg);
449 goto err_disable_vdd_reg;
450 }
451
452 err = regulator_enable(data->vref_reg);
453 if (err)
454 goto err_disable_vdd_reg;
455 }
456
457 indio_dev->name = id->name;
458 indio_dev->info = &mcp4725_info;
459 indio_dev->channels = info->chan_spec;
460 indio_dev->num_channels = 1;
461 indio_dev->modes = INDIO_DIRECT_MODE;
462
463 /* read current DAC value and settings */
464 err = i2c_master_recv(client, inbuf, info->dac_reg_offset);
465
466 if (err < 0) {
467 dev_err(&client->dev, "failed to read DAC value");
468 goto err_disable_vref_reg;
469 }
470 pd = (inbuf[0] >> 1) & 0x3;
471 data->powerdown = pd > 0;
472 data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
473 data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
474 if (!info->use_ext_ref_voltage)
475 ref = (inbuf[3] >> 3) & 0x3;
476
477 if (!info->use_ext_ref_voltage && ref != data->ref_mode) {
478 dev_info(&client->dev,
479 "voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
480 data->ref_mode, ref, data->ref_mode);
481 err = mcp4726_set_cfg(indio_dev);
482 if (err < 0)
483 goto err_disable_vref_reg;
484 }
485
486 err = iio_device_register(indio_dev);
487 if (err)
488 goto err_disable_vref_reg;
489
490 return 0;
491
492 err_disable_vref_reg:
493 if (data->vref_reg)
494 regulator_disable(data->vref_reg);
495
496 err_disable_vdd_reg:
497 regulator_disable(data->vdd_reg);
498
499 return err;
500 }
501
mcp4725_remove(struct i2c_client * client)502 static void mcp4725_remove(struct i2c_client *client)
503 {
504 struct iio_dev *indio_dev = i2c_get_clientdata(client);
505 struct mcp4725_data *data = iio_priv(indio_dev);
506
507 iio_device_unregister(indio_dev);
508
509 if (data->vref_reg)
510 regulator_disable(data->vref_reg);
511 regulator_disable(data->vdd_reg);
512 }
513
514 static const struct mcp4725_chip_info mcp4725 = {
515 .chan_spec = &mcp472x_channel[MCP4725],
516 .dac_reg_offset = 3,
517 .use_ext_ref_voltage = true,
518 };
519
520 static const struct mcp4725_chip_info mcp4726 = {
521 .chan_spec = &mcp472x_channel[MCP4726],
522 .dac_reg_offset = 4,
523 };
524
525 static const struct i2c_device_id mcp4725_id[] = {
526 { "mcp4725", (kernel_ulong_t)&mcp4725 },
527 { "mcp4726", (kernel_ulong_t)&mcp4726 },
528 { }
529 };
530 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
531
532 static const struct of_device_id mcp4725_of_match[] = {
533 {
534 .compatible = "microchip,mcp4725",
535 .data = &mcp4725
536 },
537 {
538 .compatible = "microchip,mcp4726",
539 .data = &mcp4726
540 },
541 { }
542 };
543 MODULE_DEVICE_TABLE(of, mcp4725_of_match);
544
545 static struct i2c_driver mcp4725_driver = {
546 .driver = {
547 .name = "mcp4725",
548 .of_match_table = mcp4725_of_match,
549 .pm = pm_sleep_ptr(&mcp4725_pm_ops),
550 },
551 .probe = mcp4725_probe,
552 .remove = mcp4725_remove,
553 .id_table = mcp4725_id,
554 };
555 module_i2c_driver(mcp4725_driver);
556
557 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
558 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
559 MODULE_LICENSE("GPL");
560