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
33struct 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
45static int __maybe_unused 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	int ret;
51
52	outbuf[0] = (data->powerdown_mode + 1) << 4;
53	outbuf[1] = 0;
54	data->powerdown = true;
55
56	ret = i2c_master_send(data->client, outbuf, 2);
57	if (ret < 0)
58		return ret;
59	else if (ret != 2)
60		return -EIO;
61	return 0;
62}
63
64static int __maybe_unused mcp4725_resume(struct device *dev)
65{
66	struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
67		to_i2c_client(dev)));
68	u8 outbuf[2];
69	int ret;
70
71	/* restore previous DAC value */
72	outbuf[0] = (data->dac_value >> 8) & 0xf;
73	outbuf[1] = data->dac_value & 0xff;
74	data->powerdown = false;
75
76	ret = i2c_master_send(data->client, outbuf, 2);
77	if (ret < 0)
78		return ret;
79	else if (ret != 2)
80		return -EIO;
81	return 0;
82}
83static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
84
85static ssize_t mcp4725_store_eeprom(struct device *dev,
86	struct device_attribute *attr, const char *buf, size_t len)
87{
88	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
89	struct mcp4725_data *data = iio_priv(indio_dev);
90	int tries = 20;
91	u8 inoutbuf[3];
92	bool state;
93	int ret;
94
95	ret = strtobool(buf, &state);
96	if (ret < 0)
97		return ret;
98
99	if (!state)
100		return 0;
101
102	inoutbuf[0] = 0x60; /* write EEPROM */
103	inoutbuf[0] |= data->ref_mode << 3;
104	inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
105	inoutbuf[1] = data->dac_value >> 4;
106	inoutbuf[2] = (data->dac_value & 0xf) << 4;
107
108	ret = i2c_master_send(data->client, inoutbuf, 3);
109	if (ret < 0)
110		return ret;
111	else if (ret != 3)
112		return -EIO;
113
114	/* wait for write complete, takes up to 50ms */
115	while (tries--) {
116		msleep(20);
117		ret = i2c_master_recv(data->client, inoutbuf, 3);
118		if (ret < 0)
119			return ret;
120		else if (ret != 3)
121			return -EIO;
122
123		if (inoutbuf[0] & 0x80)
124			break;
125	}
126
127	if (tries < 0) {
128		dev_err(&data->client->dev,
129			"mcp4725_store_eeprom() failed, incomplete\n");
130		return -EIO;
131	}
132
133	return len;
134}
135
136static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
137
138static struct attribute *mcp4725_attributes[] = {
139	&iio_dev_attr_store_eeprom.dev_attr.attr,
140	NULL,
141};
142
143static const struct attribute_group mcp4725_attribute_group = {
144	.attrs = mcp4725_attributes,
145};
146
147static const char * const mcp4725_powerdown_modes[] = {
148	"1kohm_to_gnd",
149	"100kohm_to_gnd",
150	"500kohm_to_gnd"
151};
152
153static const char * const mcp4726_powerdown_modes[] = {
154	"1kohm_to_gnd",
155	"125kohm_to_gnd",
156	"640kohm_to_gnd"
157};
158
159static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
160	const struct iio_chan_spec *chan)
161{
162	struct mcp4725_data *data = iio_priv(indio_dev);
163
164	return data->powerdown_mode;
165}
166
167static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
168	const struct iio_chan_spec *chan, unsigned mode)
169{
170	struct mcp4725_data *data = iio_priv(indio_dev);
171
172	data->powerdown_mode = mode;
173
174	return 0;
175}
176
177static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
178	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
179{
180	struct mcp4725_data *data = iio_priv(indio_dev);
181
182	return sprintf(buf, "%d\n", data->powerdown);
183}
184
185static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
186	 uintptr_t private, const struct iio_chan_spec *chan,
187	 const char *buf, size_t len)
188{
189	struct mcp4725_data *data = iio_priv(indio_dev);
190	bool state;
191	int ret;
192
193	ret = strtobool(buf, &state);
194	if (ret)
195		return ret;
196
197	if (state)
198		ret = mcp4725_suspend(&data->client->dev);
199	else
200		ret = mcp4725_resume(&data->client->dev);
201	if (ret < 0)
202		return ret;
203
204	return len;
205}
206
207enum chip_id {
208	MCP4725,
209	MCP4726,
210};
211
212static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
213	[MCP4725] = {
214		.items = mcp4725_powerdown_modes,
215		.num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
216		.get = mcp4725_get_powerdown_mode,
217		.set = mcp4725_set_powerdown_mode,
218	},
219	[MCP4726] = {
220		.items = mcp4726_powerdown_modes,
221		.num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
222		.get = mcp4725_get_powerdown_mode,
223		.set = mcp4725_set_powerdown_mode,
224	},
225};
226
227static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
228	{
229		.name = "powerdown",
230		.read = mcp4725_read_powerdown,
231		.write = mcp4725_write_powerdown,
232		.shared = IIO_SEPARATE,
233	},
234	IIO_ENUM("powerdown_mode", IIO_SEPARATE,
235			&mcp472x_powerdown_mode_enum[MCP4725]),
236	IIO_ENUM_AVAILABLE("powerdown_mode",
237			&mcp472x_powerdown_mode_enum[MCP4725]),
238	{ },
239};
240
241static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
242	{
243		.name = "powerdown",
244		.read = mcp4725_read_powerdown,
245		.write = mcp4725_write_powerdown,
246		.shared = IIO_SEPARATE,
247	},
248	IIO_ENUM("powerdown_mode", IIO_SEPARATE,
249			&mcp472x_powerdown_mode_enum[MCP4726]),
250	IIO_ENUM_AVAILABLE("powerdown_mode",
251			&mcp472x_powerdown_mode_enum[MCP4726]),
252	{ },
253};
254
255static const struct iio_chan_spec mcp472x_channel[] = {
256	[MCP4725] = {
257		.type		= IIO_VOLTAGE,
258		.indexed	= 1,
259		.output		= 1,
260		.channel	= 0,
261		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
262		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
263		.ext_info	= mcp4725_ext_info,
264	},
265	[MCP4726] = {
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	= mcp4726_ext_info,
273	},
274};
275
276static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
277{
278	struct mcp4725_data *data = iio_priv(indio_dev);
279	u8 outbuf[2];
280	int ret;
281
282	if (val >= (1 << 12) || val < 0)
283		return -EINVAL;
284
285	outbuf[0] = (val >> 8) & 0xf;
286	outbuf[1] = val & 0xff;
287
288	ret = i2c_master_send(data->client, outbuf, 2);
289	if (ret < 0)
290		return ret;
291	else if (ret != 2)
292		return -EIO;
293	else
294		return 0;
295}
296
297static int mcp4726_set_cfg(struct iio_dev *indio_dev)
298{
299	struct mcp4725_data *data = iio_priv(indio_dev);
300	u8 outbuf[3];
301	int ret;
302
303	outbuf[0] = 0x40;
304	outbuf[0] |= data->ref_mode << 3;
305	if (data->powerdown)
306		outbuf[0] |= data->powerdown << 1;
307	outbuf[1] = data->dac_value >> 4;
308	outbuf[2] = (data->dac_value & 0xf) << 4;
309
310	ret = i2c_master_send(data->client, outbuf, 3);
311	if (ret < 0)
312		return ret;
313	else if (ret != 3)
314		return -EIO;
315	else
316		return 0;
317}
318
319static int mcp4725_read_raw(struct iio_dev *indio_dev,
320			   struct iio_chan_spec const *chan,
321			   int *val, int *val2, long mask)
322{
323	struct mcp4725_data *data = iio_priv(indio_dev);
324	int ret;
325
326	switch (mask) {
327	case IIO_CHAN_INFO_RAW:
328		*val = data->dac_value;
329		return IIO_VAL_INT;
330	case IIO_CHAN_INFO_SCALE:
331		if (data->ref_mode == MCP472X_REF_VDD)
332			ret = regulator_get_voltage(data->vdd_reg);
333		else
334			ret = regulator_get_voltage(data->vref_reg);
335
336		if (ret < 0)
337			return ret;
338
339		*val = ret / 1000;
340		*val2 = 12;
341		return IIO_VAL_FRACTIONAL_LOG2;
342	}
343	return -EINVAL;
344}
345
346static int mcp4725_write_raw(struct iio_dev *indio_dev,
347			       struct iio_chan_spec const *chan,
348			       int val, int val2, long mask)
349{
350	struct mcp4725_data *data = iio_priv(indio_dev);
351	int ret;
352
353	switch (mask) {
354	case IIO_CHAN_INFO_RAW:
355		ret = mcp4725_set_value(indio_dev, val);
356		data->dac_value = val;
357		break;
358	default:
359		ret = -EINVAL;
360		break;
361	}
362
363	return ret;
364}
365
366static const struct iio_info mcp4725_info = {
367	.read_raw = mcp4725_read_raw,
368	.write_raw = mcp4725_write_raw,
369	.attrs = &mcp4725_attribute_group,
370};
371
372static int mcp4725_probe_dt(struct device *dev,
373			    struct mcp4725_platform_data *pdata)
374{
375	/* check if is the vref-supply defined */
376	pdata->use_vref = device_property_read_bool(dev, "vref-supply");
377	pdata->vref_buffered =
378		device_property_read_bool(dev, "microchip,vref-buffered");
379
380	return 0;
381}
382
383static int mcp4725_probe(struct i2c_client *client,
384			 const struct i2c_device_id *id)
385{
386	struct mcp4725_data *data;
387	struct iio_dev *indio_dev;
388	struct mcp4725_platform_data *pdata, pdata_dt;
389	u8 inbuf[4];
390	u8 pd;
391	u8 ref;
392	int err;
393
394	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
395	if (indio_dev == NULL)
396		return -ENOMEM;
397	data = iio_priv(indio_dev);
398	i2c_set_clientdata(client, indio_dev);
399	data->client = client;
400	if (dev_fwnode(&client->dev))
401		data->id = (enum chip_id)device_get_match_data(&client->dev);
402	else
403		data->id = id->driver_data;
404	pdata = dev_get_platdata(&client->dev);
405
406	if (!pdata) {
407		err = mcp4725_probe_dt(&client->dev, &pdata_dt);
408		if (err) {
409			dev_err(&client->dev,
410				"invalid platform or devicetree data");
411			return err;
412		}
413		pdata = &pdata_dt;
414	}
415
416	if (data->id == MCP4725 && pdata->use_vref) {
417		dev_err(&client->dev,
418			"external reference is unavailable on MCP4725");
419		return -EINVAL;
420	}
421
422	if (!pdata->use_vref && pdata->vref_buffered) {
423		dev_err(&client->dev,
424			"buffering is unavailable on the internal reference");
425		return -EINVAL;
426	}
427
428	if (!pdata->use_vref)
429		data->ref_mode = MCP472X_REF_VDD;
430	else
431		data->ref_mode = pdata->vref_buffered ?
432			MCP472X_REF_VREF_BUFFERED :
433			MCP472X_REF_VREF_UNBUFFERED;
434
435	data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
436	if (IS_ERR(data->vdd_reg))
437		return PTR_ERR(data->vdd_reg);
438
439	err = regulator_enable(data->vdd_reg);
440	if (err)
441		return err;
442
443	if (pdata->use_vref) {
444		data->vref_reg = devm_regulator_get(&client->dev, "vref");
445		if (IS_ERR(data->vref_reg)) {
446			err = PTR_ERR(data->vref_reg);
447			goto err_disable_vdd_reg;
448		}
449
450		err = regulator_enable(data->vref_reg);
451		if (err)
452			goto err_disable_vdd_reg;
453	}
454
455	indio_dev->name = id->name;
456	indio_dev->info = &mcp4725_info;
457	indio_dev->channels = &mcp472x_channel[id->driver_data];
458	indio_dev->num_channels = 1;
459	indio_dev->modes = INDIO_DIRECT_MODE;
460
461	/* read current DAC value and settings */
462	err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4);
463
464	if (err < 0) {
465		dev_err(&client->dev, "failed to read DAC value");
466		goto err_disable_vref_reg;
467	}
468	pd = (inbuf[0] >> 1) & 0x3;
469	data->powerdown = pd > 0;
470	data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
471	data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
472	if (data->id == MCP4726)
473		ref = (inbuf[3] >> 3) & 0x3;
474
475	if (data->id == MCP4726 && ref != data->ref_mode) {
476		dev_info(&client->dev,
477			"voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
478			data->ref_mode, ref, data->ref_mode);
479		err = mcp4726_set_cfg(indio_dev);
480		if (err < 0)
481			goto err_disable_vref_reg;
482	}
483
484	err = iio_device_register(indio_dev);
485	if (err)
486		goto err_disable_vref_reg;
487
488	return 0;
489
490err_disable_vref_reg:
491	if (data->vref_reg)
492		regulator_disable(data->vref_reg);
493
494err_disable_vdd_reg:
495	regulator_disable(data->vdd_reg);
496
497	return err;
498}
499
500static int mcp4725_remove(struct i2c_client *client)
501{
502	struct iio_dev *indio_dev = i2c_get_clientdata(client);
503	struct mcp4725_data *data = iio_priv(indio_dev);
504
505	iio_device_unregister(indio_dev);
506
507	if (data->vref_reg)
508		regulator_disable(data->vref_reg);
509	regulator_disable(data->vdd_reg);
510
511	return 0;
512}
513
514static const struct i2c_device_id mcp4725_id[] = {
515	{ "mcp4725", MCP4725 },
516	{ "mcp4726", MCP4726 },
517	{ }
518};
519MODULE_DEVICE_TABLE(i2c, mcp4725_id);
520
521static const struct of_device_id mcp4725_of_match[] = {
522	{
523		.compatible = "microchip,mcp4725",
524		.data = (void *)MCP4725
525	},
526	{
527		.compatible = "microchip,mcp4726",
528		.data = (void *)MCP4726
529	},
530	{ }
531};
532MODULE_DEVICE_TABLE(of, mcp4725_of_match);
533
534static struct i2c_driver mcp4725_driver = {
535	.driver = {
536		.name	= MCP4725_DRV_NAME,
537		.of_match_table = mcp4725_of_match,
538		.pm	= &mcp4725_pm_ops,
539	},
540	.probe		= mcp4725_probe,
541	.remove		= mcp4725_remove,
542	.id_table	= mcp4725_id,
543};
544module_i2c_driver(mcp4725_driver);
545
546MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
547MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
548MODULE_LICENSE("GPL");
549