1 /*
2 * mcp4725.c - Support for Microchip MCP4725/6
3 *
4 * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
5 *
6 * Based on max517 by Roland Stigge <stigge@antcom.de>
7 *
8 * This file is subject to the terms and conditions of version 2 of
9 * the GNU General Public License. See the file COPYING in the main
10 * directory of this archive for more details.
11 *
12 * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
13 * (7-bit I2C slave address 0x60, the three LSBs can be configured in
14 * hardware)
15 */
16
17 #include <linux/module.h>
18 #include <linux/i2c.h>
19 #include <linux/err.h>
20 #include <linux/delay.h>
21 #include <linux/regulator/consumer.h>
22 #include <linux/of_device.h>
23 #include <linux/of.h>
24
25 #include <linux/iio/iio.h>
26 #include <linux/iio/sysfs.h>
27
28 #include <linux/iio/dac/mcp4725.h>
29
30 #define MCP4725_DRV_NAME "mcp4725"
31
32 #define MCP472X_REF_VDD 0x00
33 #define MCP472X_REF_VREF_UNBUFFERED 0x02
34 #define MCP472X_REF_VREF_BUFFERED 0x03
35
36 struct mcp4725_data {
37 struct i2c_client *client;
38 int id;
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
87 #ifdef CONFIG_PM_SLEEP
88 static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
89 #define MCP4725_PM_OPS (&mcp4725_pm_ops)
90 #else
91 #define MCP4725_PM_OPS NULL
92 #endif
93
mcp4725_store_eeprom(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)94 static ssize_t mcp4725_store_eeprom(struct device *dev,
95 struct device_attribute *attr, const char *buf, size_t len)
96 {
97 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
98 struct mcp4725_data *data = iio_priv(indio_dev);
99 int tries = 20;
100 u8 inoutbuf[3];
101 bool state;
102 int ret;
103
104 ret = strtobool(buf, &state);
105 if (ret < 0)
106 return ret;
107
108 if (!state)
109 return 0;
110
111 inoutbuf[0] = 0x60; /* write EEPROM */
112 inoutbuf[0] |= data->ref_mode << 3;
113 inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
114 inoutbuf[1] = data->dac_value >> 4;
115 inoutbuf[2] = (data->dac_value & 0xf) << 4;
116
117 ret = i2c_master_send(data->client, inoutbuf, 3);
118 if (ret < 0)
119 return ret;
120 else if (ret != 3)
121 return -EIO;
122
123 /* wait for write complete, takes up to 50ms */
124 while (tries--) {
125 msleep(20);
126 ret = i2c_master_recv(data->client, inoutbuf, 3);
127 if (ret < 0)
128 return ret;
129 else if (ret != 3)
130 return -EIO;
131
132 if (inoutbuf[0] & 0x80)
133 break;
134 }
135
136 if (tries < 0) {
137 dev_err(&data->client->dev,
138 "mcp4725_store_eeprom() failed, incomplete\n");
139 return -EIO;
140 }
141
142 return len;
143 }
144
145 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
146
147 static struct attribute *mcp4725_attributes[] = {
148 &iio_dev_attr_store_eeprom.dev_attr.attr,
149 NULL,
150 };
151
152 static const struct attribute_group mcp4725_attribute_group = {
153 .attrs = mcp4725_attributes,
154 };
155
156 static const char * const mcp4725_powerdown_modes[] = {
157 "1kohm_to_gnd",
158 "100kohm_to_gnd",
159 "500kohm_to_gnd"
160 };
161
162 static const char * const mcp4726_powerdown_modes[] = {
163 "1kohm_to_gnd",
164 "125kohm_to_gnd",
165 "640kohm_to_gnd"
166 };
167
mcp4725_get_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan)168 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
169 const struct iio_chan_spec *chan)
170 {
171 struct mcp4725_data *data = iio_priv(indio_dev);
172
173 return data->powerdown_mode;
174 }
175
mcp4725_set_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,unsigned mode)176 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
177 const struct iio_chan_spec *chan, unsigned mode)
178 {
179 struct mcp4725_data *data = iio_priv(indio_dev);
180
181 data->powerdown_mode = mode;
182
183 return 0;
184 }
185
mcp4725_read_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)186 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
187 uintptr_t private, const struct iio_chan_spec *chan, char *buf)
188 {
189 struct mcp4725_data *data = iio_priv(indio_dev);
190
191 return sprintf(buf, "%d\n", data->powerdown);
192 }
193
mcp4725_write_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)194 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
195 uintptr_t private, const struct iio_chan_spec *chan,
196 const char *buf, size_t len)
197 {
198 struct mcp4725_data *data = iio_priv(indio_dev);
199 bool state;
200 int ret;
201
202 ret = strtobool(buf, &state);
203 if (ret)
204 return ret;
205
206 if (state)
207 ret = mcp4725_suspend(&data->client->dev);
208 else
209 ret = mcp4725_resume(&data->client->dev);
210 if (ret < 0)
211 return ret;
212
213 return len;
214 }
215
216 enum chip_id {
217 MCP4725,
218 MCP4726,
219 };
220
221 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
222 [MCP4725] = {
223 .items = mcp4725_powerdown_modes,
224 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
225 .get = mcp4725_get_powerdown_mode,
226 .set = mcp4725_set_powerdown_mode,
227 },
228 [MCP4726] = {
229 .items = mcp4726_powerdown_modes,
230 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
231 .get = mcp4725_get_powerdown_mode,
232 .set = mcp4725_set_powerdown_mode,
233 },
234 };
235
236 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
237 {
238 .name = "powerdown",
239 .read = mcp4725_read_powerdown,
240 .write = mcp4725_write_powerdown,
241 .shared = IIO_SEPARATE,
242 },
243 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
244 &mcp472x_powerdown_mode_enum[MCP4725]),
245 IIO_ENUM_AVAILABLE("powerdown_mode",
246 &mcp472x_powerdown_mode_enum[MCP4725]),
247 { },
248 };
249
250 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
251 {
252 .name = "powerdown",
253 .read = mcp4725_read_powerdown,
254 .write = mcp4725_write_powerdown,
255 .shared = IIO_SEPARATE,
256 },
257 IIO_ENUM("powerdown_mode", IIO_SEPARATE,
258 &mcp472x_powerdown_mode_enum[MCP4726]),
259 IIO_ENUM_AVAILABLE("powerdown_mode",
260 &mcp472x_powerdown_mode_enum[MCP4726]),
261 { },
262 };
263
264 static const struct iio_chan_spec mcp472x_channel[] = {
265 [MCP4725] = {
266 .type = IIO_VOLTAGE,
267 .indexed = 1,
268 .output = 1,
269 .channel = 0,
270 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
271 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
272 .ext_info = mcp4725_ext_info,
273 },
274 [MCP4726] = {
275 .type = IIO_VOLTAGE,
276 .indexed = 1,
277 .output = 1,
278 .channel = 0,
279 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
280 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
281 .ext_info = mcp4726_ext_info,
282 },
283 };
284
mcp4725_set_value(struct iio_dev * indio_dev,int val)285 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
286 {
287 struct mcp4725_data *data = iio_priv(indio_dev);
288 u8 outbuf[2];
289 int ret;
290
291 if (val >= (1 << 12) || val < 0)
292 return -EINVAL;
293
294 outbuf[0] = (val >> 8) & 0xf;
295 outbuf[1] = val & 0xff;
296
297 ret = i2c_master_send(data->client, outbuf, 2);
298 if (ret < 0)
299 return ret;
300 else if (ret != 2)
301 return -EIO;
302 else
303 return 0;
304 }
305
mcp4726_set_cfg(struct iio_dev * indio_dev)306 static int mcp4726_set_cfg(struct iio_dev *indio_dev)
307 {
308 struct mcp4725_data *data = iio_priv(indio_dev);
309 u8 outbuf[3];
310 int ret;
311
312 outbuf[0] = 0x40;
313 outbuf[0] |= data->ref_mode << 3;
314 if (data->powerdown)
315 outbuf[0] |= data->powerdown << 1;
316 outbuf[1] = data->dac_value >> 4;
317 outbuf[2] = (data->dac_value & 0xf) << 4;
318
319 ret = i2c_master_send(data->client, outbuf, 3);
320 if (ret < 0)
321 return ret;
322 else if (ret != 3)
323 return -EIO;
324 else
325 return 0;
326 }
327
mcp4725_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)328 static int mcp4725_read_raw(struct iio_dev *indio_dev,
329 struct iio_chan_spec const *chan,
330 int *val, int *val2, long mask)
331 {
332 struct mcp4725_data *data = iio_priv(indio_dev);
333 int ret;
334
335 switch (mask) {
336 case IIO_CHAN_INFO_RAW:
337 *val = data->dac_value;
338 return IIO_VAL_INT;
339 case IIO_CHAN_INFO_SCALE:
340 if (data->ref_mode == MCP472X_REF_VDD)
341 ret = regulator_get_voltage(data->vdd_reg);
342 else
343 ret = regulator_get_voltage(data->vref_reg);
344
345 if (ret < 0)
346 return ret;
347
348 *val = ret / 1000;
349 *val2 = 12;
350 return IIO_VAL_FRACTIONAL_LOG2;
351 }
352 return -EINVAL;
353 }
354
mcp4725_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)355 static int mcp4725_write_raw(struct iio_dev *indio_dev,
356 struct iio_chan_spec const *chan,
357 int val, int val2, long mask)
358 {
359 struct mcp4725_data *data = iio_priv(indio_dev);
360 int ret;
361
362 switch (mask) {
363 case IIO_CHAN_INFO_RAW:
364 ret = mcp4725_set_value(indio_dev, val);
365 data->dac_value = val;
366 break;
367 default:
368 ret = -EINVAL;
369 break;
370 }
371
372 return ret;
373 }
374
375 static const struct iio_info mcp4725_info = {
376 .read_raw = mcp4725_read_raw,
377 .write_raw = mcp4725_write_raw,
378 .attrs = &mcp4725_attribute_group,
379 };
380
381 #ifdef CONFIG_OF
mcp4725_probe_dt(struct device * dev,struct mcp4725_platform_data * pdata)382 static int mcp4725_probe_dt(struct device *dev,
383 struct mcp4725_platform_data *pdata)
384 {
385 struct device_node *np = dev->of_node;
386
387 if (!np)
388 return -ENODEV;
389
390 /* check if is the vref-supply defined */
391 pdata->use_vref = of_property_read_bool(np, "vref-supply");
392 pdata->vref_buffered =
393 of_property_read_bool(np, "microchip,vref-buffered");
394
395 return 0;
396 }
397 #else
mcp4725_probe_dt(struct device * dev,struct mcp4725_platform_data * platform_data)398 static int mcp4725_probe_dt(struct device *dev,
399 struct mcp4725_platform_data *platform_data)
400 {
401 return -ENODEV;
402 }
403 #endif
404
mcp4725_probe(struct i2c_client * client,const struct i2c_device_id * id)405 static int mcp4725_probe(struct i2c_client *client,
406 const struct i2c_device_id *id)
407 {
408 struct mcp4725_data *data;
409 struct iio_dev *indio_dev;
410 struct mcp4725_platform_data *pdata, pdata_dt;
411 u8 inbuf[4];
412 u8 pd;
413 u8 ref;
414 int err;
415
416 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
417 if (indio_dev == NULL)
418 return -ENOMEM;
419 data = iio_priv(indio_dev);
420 i2c_set_clientdata(client, indio_dev);
421 data->client = client;
422 if (client->dev.of_node)
423 data->id = (enum chip_id)of_device_get_match_data(&client->dev);
424 else
425 data->id = id->driver_data;
426 pdata = dev_get_platdata(&client->dev);
427
428 if (!pdata) {
429 err = mcp4725_probe_dt(&client->dev, &pdata_dt);
430 if (err) {
431 dev_err(&client->dev,
432 "invalid platform or devicetree data");
433 return err;
434 }
435 pdata = &pdata_dt;
436 }
437
438 if (data->id == MCP4725 && pdata->use_vref) {
439 dev_err(&client->dev,
440 "external reference is unavailable on MCP4725");
441 return -EINVAL;
442 }
443
444 if (!pdata->use_vref && pdata->vref_buffered) {
445 dev_err(&client->dev,
446 "buffering is unavailable on the internal reference");
447 return -EINVAL;
448 }
449
450 if (!pdata->use_vref)
451 data->ref_mode = MCP472X_REF_VDD;
452 else
453 data->ref_mode = pdata->vref_buffered ?
454 MCP472X_REF_VREF_BUFFERED :
455 MCP472X_REF_VREF_UNBUFFERED;
456
457 data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
458 if (IS_ERR(data->vdd_reg))
459 return PTR_ERR(data->vdd_reg);
460
461 err = regulator_enable(data->vdd_reg);
462 if (err)
463 return err;
464
465 if (pdata->use_vref) {
466 data->vref_reg = devm_regulator_get(&client->dev, "vref");
467 if (IS_ERR(data->vref_reg)) {
468 err = PTR_ERR(data->vref_reg);
469 goto err_disable_vdd_reg;
470 }
471
472 err = regulator_enable(data->vref_reg);
473 if (err)
474 goto err_disable_vdd_reg;
475 }
476
477 indio_dev->dev.parent = &client->dev;
478 indio_dev->name = id->name;
479 indio_dev->info = &mcp4725_info;
480 indio_dev->channels = &mcp472x_channel[id->driver_data];
481 indio_dev->num_channels = 1;
482 indio_dev->modes = INDIO_DIRECT_MODE;
483
484 /* read current DAC value and settings */
485 err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4);
486
487 if (err < 0) {
488 dev_err(&client->dev, "failed to read DAC value");
489 goto err_disable_vref_reg;
490 }
491 pd = (inbuf[0] >> 1) & 0x3;
492 data->powerdown = pd > 0;
493 data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
494 data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
495 if (data->id == MCP4726)
496 ref = (inbuf[3] >> 3) & 0x3;
497
498 if (data->id == MCP4726 && ref != data->ref_mode) {
499 dev_info(&client->dev,
500 "voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
501 data->ref_mode, ref, data->ref_mode);
502 err = mcp4726_set_cfg(indio_dev);
503 if (err < 0)
504 goto err_disable_vref_reg;
505 }
506
507 err = iio_device_register(indio_dev);
508 if (err)
509 goto err_disable_vref_reg;
510
511 return 0;
512
513 err_disable_vref_reg:
514 if (data->vref_reg)
515 regulator_disable(data->vref_reg);
516
517 err_disable_vdd_reg:
518 regulator_disable(data->vdd_reg);
519
520 return err;
521 }
522
mcp4725_remove(struct i2c_client * client)523 static int mcp4725_remove(struct i2c_client *client)
524 {
525 struct iio_dev *indio_dev = i2c_get_clientdata(client);
526 struct mcp4725_data *data = iio_priv(indio_dev);
527
528 iio_device_unregister(indio_dev);
529
530 if (data->vref_reg)
531 regulator_disable(data->vref_reg);
532 regulator_disable(data->vdd_reg);
533
534 return 0;
535 }
536
537 static const struct i2c_device_id mcp4725_id[] = {
538 { "mcp4725", MCP4725 },
539 { "mcp4726", MCP4726 },
540 { }
541 };
542 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
543
544 #ifdef CONFIG_OF
545 static const struct of_device_id mcp4725_of_match[] = {
546 {
547 .compatible = "microchip,mcp4725",
548 .data = (void *)MCP4725
549 },
550 {
551 .compatible = "microchip,mcp4726",
552 .data = (void *)MCP4726
553 },
554 { }
555 };
556 MODULE_DEVICE_TABLE(of, mcp4725_of_match);
557 #endif
558
559 static struct i2c_driver mcp4725_driver = {
560 .driver = {
561 .name = MCP4725_DRV_NAME,
562 .of_match_table = of_match_ptr(mcp4725_of_match),
563 .pm = MCP4725_PM_OPS,
564 },
565 .probe = mcp4725_probe,
566 .remove = mcp4725_remove,
567 .id_table = mcp4725_id,
568 };
569 module_i2c_driver(mcp4725_driver);
570
571 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
572 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
573 MODULE_LICENSE("GPL");
574