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_chip_info {
34 const struct iio_chan_spec *chan_spec;
35 u8 dac_reg_offset;
36 bool use_ext_ref_voltage;
37 };
38
39 struct mcp4725_data {
40 struct i2c_client *client;
41 unsigned ref_mode;
42 bool vref_buffered;
43 u16 dac_value;
44 bool powerdown;
45 unsigned powerdown_mode;
46 struct regulator *vdd_reg;
47 struct regulator *vref_reg;
48 };
49
mcp4725_suspend(struct device * dev)50 static int mcp4725_suspend(struct device *dev)
51 {
52 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
53 to_i2c_client(dev)));
54 u8 outbuf[2];
55 int ret;
56
57 outbuf[0] = (data->powerdown_mode + 1) << 4;
58 outbuf[1] = 0;
59 data->powerdown = true;
60
61 ret = i2c_master_send(data->client, outbuf, 2);
62 if (ret < 0)
63 return ret;
64 else if (ret != 2)
65 return -EIO;
66 return 0;
67 }
68
mcp4725_resume(struct device * dev)69 static int mcp4725_resume(struct device *dev)
70 {
71 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
72 to_i2c_client(dev)));
73 u8 outbuf[2];
74 int ret;
75
76 /* restore previous DAC value */
77 outbuf[0] = (data->dac_value >> 8) & 0xf;
78 outbuf[1] = data->dac_value & 0xff;
79 data->powerdown = false;
80
81 ret = i2c_master_send(data->client, outbuf, 2);
82 if (ret < 0)
83 return ret;
84 else if (ret != 2)
85 return -EIO;
86 return 0;
87 }
88 static DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend,
89 mcp4725_resume);
90
mcp4725_store_eeprom(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)91 static ssize_t mcp4725_store_eeprom(struct device *dev,
92 struct device_attribute *attr, const char *buf, size_t len)
93 {
94 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
95 struct mcp4725_data *data = iio_priv(indio_dev);
96 int tries = 20;
97 u8 inoutbuf[3];
98 bool state;
99 int ret;
100
101 ret = kstrtobool(buf, &state);
102 if (ret < 0)
103 return ret;
104
105 if (!state)
106 return 0;
107
108 inoutbuf[0] = 0x60; /* write EEPROM */
109 inoutbuf[0] |= data->ref_mode << 3;
110 inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
111 inoutbuf[1] = data->dac_value >> 4;
112 inoutbuf[2] = (data->dac_value & 0xf) << 4;
113
114 ret = i2c_master_send(data->client, inoutbuf, 3);
115 if (ret < 0)
116 return ret;
117 else if (ret != 3)
118 return -EIO;
119
120 /* wait for write complete, takes up to 50ms */
121 while (tries--) {
122 msleep(20);
123 ret = i2c_master_recv(data->client, inoutbuf, 3);
124 if (ret < 0)
125 return ret;
126 else if (ret != 3)
127 return -EIO;
128
129 if (inoutbuf[0] & 0x80)
130 break;
131 }
132
133 if (tries < 0) {
134 dev_err(&data->client->dev,
135 "mcp4725_store_eeprom() failed, incomplete\n");
136 return -EIO;
137 }
138
139 return len;
140 }
141
142 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
143
144 static struct attribute *mcp4725_attributes[] = {
145 &iio_dev_attr_store_eeprom.dev_attr.attr,
146 NULL,
147 };
148
149 static const struct attribute_group mcp4725_attribute_group = {
150 .attrs = mcp4725_attributes,
151 };
152
153 static const char * const mcp4725_powerdown_modes[] = {
154 "1kohm_to_gnd",
155 "100kohm_to_gnd",
156 "500kohm_to_gnd"
157 };
158
159 static const char * const mcp4726_powerdown_modes[] = {
160 "1kohm_to_gnd",
161 "125kohm_to_gnd",
162 "640kohm_to_gnd"
163 };
164
mcp4725_get_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan)165 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
166 const struct iio_chan_spec *chan)
167 {
168 struct mcp4725_data *data = iio_priv(indio_dev);
169
170 return data->powerdown_mode;
171 }
172
mcp4725_set_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,unsigned mode)173 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
174 const struct iio_chan_spec *chan, unsigned mode)
175 {
176 struct mcp4725_data *data = iio_priv(indio_dev);
177
178 data->powerdown_mode = mode;
179
180 return 0;
181 }
182
mcp4725_read_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)183 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
184 uintptr_t private, const struct iio_chan_spec *chan, char *buf)
185 {
186 struct mcp4725_data *data = iio_priv(indio_dev);
187
188 return sysfs_emit(buf, "%d\n", data->powerdown);
189 }
190
mcp4725_write_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)191 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
192 uintptr_t private, const struct iio_chan_spec *chan,
193 const char *buf, size_t len)
194 {
195 struct mcp4725_data *data = iio_priv(indio_dev);
196 bool state;
197 int ret;
198
199 ret = kstrtobool(buf, &state);
200 if (ret)
201 return ret;
202
203 if (state)
204 ret = mcp4725_suspend(&data->client->dev);
205 else
206 ret = mcp4725_resume(&data->client->dev);
207 if (ret < 0)
208 return ret;
209
210 return len;
211 }
212
213 enum chip_id {
214 MCP4725,
215 MCP4726,
216 };
217
218 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
219 [MCP4725] = {
220 .items = mcp4725_powerdown_modes,
221 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
222 .get = mcp4725_get_powerdown_mode,
223 .set = mcp4725_set_powerdown_mode,
224 },
225 [MCP4726] = {
226 .items = mcp4726_powerdown_modes,
227 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
228 .get = mcp4725_get_powerdown_mode,
229 .set = mcp4725_set_powerdown_mode,
230 },
231 };
232
233 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
234 {
235 .name = "powerdown",
236 .read = mcp4725_read_powerdown,
237 .write = mcp4725_write_powerdown,
238 .shared = IIO_SEPARATE,
239 },
240 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
241 &mcp472x_powerdown_mode_enum[MCP4725]),
242 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
243 &mcp472x_powerdown_mode_enum[MCP4725]),
244 { },
245 };
246
247 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
248 {
249 .name = "powerdown",
250 .read = mcp4725_read_powerdown,
251 .write = mcp4725_write_powerdown,
252 .shared = IIO_SEPARATE,
253 },
254 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
255 &mcp472x_powerdown_mode_enum[MCP4726]),
256 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
257 &mcp472x_powerdown_mode_enum[MCP4726]),
258 { },
259 };
260
261 static const struct iio_chan_spec mcp472x_channel[] = {
262 [MCP4725] = {
263 .type = IIO_VOLTAGE,
264 .indexed = 1,
265 .output = 1,
266 .channel = 0,
267 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
268 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
269 .ext_info = mcp4725_ext_info,
270 },
271 [MCP4726] = {
272 .type = IIO_VOLTAGE,
273 .indexed = 1,
274 .output = 1,
275 .channel = 0,
276 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
277 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
278 .ext_info = mcp4726_ext_info,
279 },
280 };
281
mcp4725_set_value(struct iio_dev * indio_dev,int val)282 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
283 {
284 struct mcp4725_data *data = iio_priv(indio_dev);
285 u8 outbuf[2];
286 int ret;
287
288 if (val >= (1 << 12) || val < 0)
289 return -EINVAL;
290
291 outbuf[0] = (val >> 8) & 0xf;
292 outbuf[1] = val & 0xff;
293
294 ret = i2c_master_send(data->client, outbuf, 2);
295 if (ret < 0)
296 return ret;
297 else if (ret != 2)
298 return -EIO;
299 else
300 return 0;
301 }
302
mcp4726_set_cfg(struct iio_dev * indio_dev)303 static int mcp4726_set_cfg(struct iio_dev *indio_dev)
304 {
305 struct mcp4725_data *data = iio_priv(indio_dev);
306 u8 outbuf[3];
307 int ret;
308
309 outbuf[0] = 0x40;
310 outbuf[0] |= data->ref_mode << 3;
311 if (data->powerdown)
312 outbuf[0] |= data->powerdown << 1;
313 outbuf[1] = data->dac_value >> 4;
314 outbuf[2] = (data->dac_value & 0xf) << 4;
315
316 ret = i2c_master_send(data->client, outbuf, 3);
317 if (ret < 0)
318 return ret;
319 else if (ret != 3)
320 return -EIO;
321 else
322 return 0;
323 }
324
mcp4725_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)325 static int mcp4725_read_raw(struct iio_dev *indio_dev,
326 struct iio_chan_spec const *chan,
327 int *val, int *val2, long mask)
328 {
329 struct mcp4725_data *data = iio_priv(indio_dev);
330 int ret;
331
332 switch (mask) {
333 case IIO_CHAN_INFO_RAW:
334 *val = data->dac_value;
335 return IIO_VAL_INT;
336 case IIO_CHAN_INFO_SCALE:
337 if (data->ref_mode == MCP472X_REF_VDD)
338 ret = regulator_get_voltage(data->vdd_reg);
339 else
340 ret = regulator_get_voltage(data->vref_reg);
341
342 if (ret < 0)
343 return ret;
344
345 *val = ret / 1000;
346 *val2 = 12;
347 return IIO_VAL_FRACTIONAL_LOG2;
348 }
349 return -EINVAL;
350 }
351
mcp4725_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)352 static int mcp4725_write_raw(struct iio_dev *indio_dev,
353 struct iio_chan_spec const *chan,
354 int val, int val2, long mask)
355 {
356 struct mcp4725_data *data = iio_priv(indio_dev);
357 int ret;
358
359 switch (mask) {
360 case IIO_CHAN_INFO_RAW:
361 ret = mcp4725_set_value(indio_dev, val);
362 data->dac_value = val;
363 break;
364 default:
365 ret = -EINVAL;
366 break;
367 }
368
369 return ret;
370 }
371
372 static const struct iio_info mcp4725_info = {
373 .read_raw = mcp4725_read_raw,
374 .write_raw = mcp4725_write_raw,
375 .attrs = &mcp4725_attribute_group,
376 };
377
mcp4725_probe_dt(struct device * dev,struct mcp4725_platform_data * pdata)378 static int mcp4725_probe_dt(struct device *dev,
379 struct mcp4725_platform_data *pdata)
380 {
381 /* check if is the vref-supply defined */
382 pdata->use_vref = device_property_read_bool(dev, "vref-supply");
383 pdata->vref_buffered =
384 device_property_read_bool(dev, "microchip,vref-buffered");
385
386 return 0;
387 }
388
mcp4725_probe(struct i2c_client * client)389 static int mcp4725_probe(struct i2c_client *client)
390 {
391 const struct i2c_device_id *id = i2c_client_get_device_id(client);
392 const struct mcp4725_chip_info *info;
393 struct mcp4725_data *data;
394 struct iio_dev *indio_dev;
395 struct mcp4725_platform_data *pdata, pdata_dt;
396 u8 inbuf[4];
397 u8 pd;
398 u8 ref;
399 int err;
400
401 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
402 if (indio_dev == NULL)
403 return -ENOMEM;
404 data = iio_priv(indio_dev);
405 i2c_set_clientdata(client, indio_dev);
406 data->client = client;
407 info = i2c_get_match_data(client);
408 pdata = dev_get_platdata(&client->dev);
409
410 if (!pdata) {
411 err = mcp4725_probe_dt(&client->dev, &pdata_dt);
412 if (err) {
413 dev_err(&client->dev,
414 "invalid platform or devicetree data");
415 return err;
416 }
417 pdata = &pdata_dt;
418 }
419
420 if (info->use_ext_ref_voltage && pdata->use_vref) {
421 dev_err(&client->dev,
422 "external reference is unavailable on MCP4725");
423 return -EINVAL;
424 }
425
426 if (!pdata->use_vref && pdata->vref_buffered) {
427 dev_err(&client->dev,
428 "buffering is unavailable on the internal reference");
429 return -EINVAL;
430 }
431
432 if (!pdata->use_vref)
433 data->ref_mode = MCP472X_REF_VDD;
434 else
435 data->ref_mode = pdata->vref_buffered ?
436 MCP472X_REF_VREF_BUFFERED :
437 MCP472X_REF_VREF_UNBUFFERED;
438
439 data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
440 if (IS_ERR(data->vdd_reg))
441 return PTR_ERR(data->vdd_reg);
442
443 err = regulator_enable(data->vdd_reg);
444 if (err)
445 return err;
446
447 if (pdata->use_vref) {
448 data->vref_reg = devm_regulator_get(&client->dev, "vref");
449 if (IS_ERR(data->vref_reg)) {
450 err = PTR_ERR(data->vref_reg);
451 goto err_disable_vdd_reg;
452 }
453
454 err = regulator_enable(data->vref_reg);
455 if (err)
456 goto err_disable_vdd_reg;
457 }
458
459 indio_dev->name = id->name;
460 indio_dev->info = &mcp4725_info;
461 indio_dev->channels = info->chan_spec;
462 indio_dev->num_channels = 1;
463 indio_dev->modes = INDIO_DIRECT_MODE;
464
465 /* read current DAC value and settings */
466 err = i2c_master_recv(client, inbuf, info->dac_reg_offset);
467
468 if (err < 0) {
469 dev_err(&client->dev, "failed to read DAC value");
470 goto err_disable_vref_reg;
471 }
472 pd = (inbuf[0] >> 1) & 0x3;
473 data->powerdown = pd > 0;
474 data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
475 data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
476 if (!info->use_ext_ref_voltage)
477 ref = (inbuf[3] >> 3) & 0x3;
478
479 if (!info->use_ext_ref_voltage && ref != data->ref_mode) {
480 dev_info(&client->dev,
481 "voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
482 data->ref_mode, ref, data->ref_mode);
483 err = mcp4726_set_cfg(indio_dev);
484 if (err < 0)
485 goto err_disable_vref_reg;
486 }
487
488 err = iio_device_register(indio_dev);
489 if (err)
490 goto err_disable_vref_reg;
491
492 return 0;
493
494 err_disable_vref_reg:
495 if (data->vref_reg)
496 regulator_disable(data->vref_reg);
497
498 err_disable_vdd_reg:
499 regulator_disable(data->vdd_reg);
500
501 return err;
502 }
503
mcp4725_remove(struct i2c_client * client)504 static void mcp4725_remove(struct i2c_client *client)
505 {
506 struct iio_dev *indio_dev = i2c_get_clientdata(client);
507 struct mcp4725_data *data = iio_priv(indio_dev);
508
509 iio_device_unregister(indio_dev);
510
511 if (data->vref_reg)
512 regulator_disable(data->vref_reg);
513 regulator_disable(data->vdd_reg);
514 }
515
516 static const struct mcp4725_chip_info mcp4725 = {
517 .chan_spec = &mcp472x_channel[MCP4725],
518 .dac_reg_offset = 3,
519 .use_ext_ref_voltage = true,
520 };
521
522 static const struct mcp4725_chip_info mcp4726 = {
523 .chan_spec = &mcp472x_channel[MCP4726],
524 .dac_reg_offset = 4,
525 };
526
527 static const struct i2c_device_id mcp4725_id[] = {
528 { "mcp4725", (kernel_ulong_t)&mcp4725 },
529 { "mcp4726", (kernel_ulong_t)&mcp4726 },
530 { }
531 };
532 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
533
534 static const struct of_device_id mcp4725_of_match[] = {
535 {
536 .compatible = "microchip,mcp4725",
537 .data = &mcp4725
538 },
539 {
540 .compatible = "microchip,mcp4726",
541 .data = &mcp4726
542 },
543 { }
544 };
545 MODULE_DEVICE_TABLE(of, mcp4725_of_match);
546
547 static struct i2c_driver mcp4725_driver = {
548 .driver = {
549 .name = MCP4725_DRV_NAME,
550 .of_match_table = mcp4725_of_match,
551 .pm = pm_sleep_ptr(&mcp4725_pm_ops),
552 },
553 .probe = mcp4725_probe,
554 .remove = mcp4725_remove,
555 .id_table = mcp4725_id,
556 };
557 module_i2c_driver(mcp4725_driver);
558
559 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
560 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
561 MODULE_LICENSE("GPL");
562