xref: /kernel/linux/linux-6.6/drivers/iio/dac/mcp4725.c (revision 62306a36) 
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 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 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 DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend,
84				mcp4725_resume);
85
86static ssize_t mcp4725_store_eeprom(struct device *dev,
87	struct device_attribute *attr, const char *buf, size_t len)
88{
89	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
90	struct mcp4725_data *data = iio_priv(indio_dev);
91	int tries = 20;
92	u8 inoutbuf[3];
93	bool state;
94	int ret;
95
96	ret = kstrtobool(buf, &state);
97	if (ret < 0)
98		return ret;
99
100	if (!state)
101		return 0;
102
103	inoutbuf[0] = 0x60; /* write EEPROM */
104	inoutbuf[0] |= data->ref_mode << 3;
105	inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0;
106	inoutbuf[1] = data->dac_value >> 4;
107	inoutbuf[2] = (data->dac_value & 0xf) << 4;
108
109	ret = i2c_master_send(data->client, inoutbuf, 3);
110	if (ret < 0)
111		return ret;
112	else if (ret != 3)
113		return -EIO;
114
115	/* wait for write complete, takes up to 50ms */
116	while (tries--) {
117		msleep(20);
118		ret = i2c_master_recv(data->client, inoutbuf, 3);
119		if (ret < 0)
120			return ret;
121		else if (ret != 3)
122			return -EIO;
123
124		if (inoutbuf[0] & 0x80)
125			break;
126	}
127
128	if (tries < 0) {
129		dev_err(&data->client->dev,
130			"mcp4725_store_eeprom() failed, incomplete\n");
131		return -EIO;
132	}
133
134	return len;
135}
136
137static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
138
139static struct attribute *mcp4725_attributes[] = {
140	&iio_dev_attr_store_eeprom.dev_attr.attr,
141	NULL,
142};
143
144static const struct attribute_group mcp4725_attribute_group = {
145	.attrs = mcp4725_attributes,
146};
147
148static const char * const mcp4725_powerdown_modes[] = {
149	"1kohm_to_gnd",
150	"100kohm_to_gnd",
151	"500kohm_to_gnd"
152};
153
154static const char * const mcp4726_powerdown_modes[] = {
155	"1kohm_to_gnd",
156	"125kohm_to_gnd",
157	"640kohm_to_gnd"
158};
159
160static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
161	const struct iio_chan_spec *chan)
162{
163	struct mcp4725_data *data = iio_priv(indio_dev);
164
165	return data->powerdown_mode;
166}
167
168static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
169	const struct iio_chan_spec *chan, unsigned mode)
170{
171	struct mcp4725_data *data = iio_priv(indio_dev);
172
173	data->powerdown_mode = mode;
174
175	return 0;
176}
177
178static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
179	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
180{
181	struct mcp4725_data *data = iio_priv(indio_dev);
182
183	return sysfs_emit(buf, "%d\n", data->powerdown);
184}
185
186static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
187	 uintptr_t private, const struct iio_chan_spec *chan,
188	 const char *buf, size_t len)
189{
190	struct mcp4725_data *data = iio_priv(indio_dev);
191	bool state;
192	int ret;
193
194	ret = kstrtobool(buf, &state);
195	if (ret)
196		return ret;
197
198	if (state)
199		ret = mcp4725_suspend(&data->client->dev);
200	else
201		ret = mcp4725_resume(&data->client->dev);
202	if (ret < 0)
203		return ret;
204
205	return len;
206}
207
208enum chip_id {
209	MCP4725,
210	MCP4726,
211};
212
213static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
214	[MCP4725] = {
215		.items = mcp4725_powerdown_modes,
216		.num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
217		.get = mcp4725_get_powerdown_mode,
218		.set = mcp4725_set_powerdown_mode,
219	},
220	[MCP4726] = {
221		.items = mcp4726_powerdown_modes,
222		.num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
223		.get = mcp4725_get_powerdown_mode,
224		.set = mcp4725_set_powerdown_mode,
225	},
226};
227
228static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
229	{
230		.name = "powerdown",
231		.read = mcp4725_read_powerdown,
232		.write = mcp4725_write_powerdown,
233		.shared = IIO_SEPARATE,
234	},
235	IIO_ENUM("powerdown_mode", IIO_SEPARATE,
236			&mcp472x_powerdown_mode_enum[MCP4725]),
237	IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
238			   &mcp472x_powerdown_mode_enum[MCP4725]),
239	{ },
240};
241
242static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
243	{
244		.name = "powerdown",
245		.read = mcp4725_read_powerdown,
246		.write = mcp4725_write_powerdown,
247		.shared = IIO_SEPARATE,
248	},
249	IIO_ENUM("powerdown_mode", IIO_SEPARATE,
250			&mcp472x_powerdown_mode_enum[MCP4726]),
251	IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE,
252			   &mcp472x_powerdown_mode_enum[MCP4726]),
253	{ },
254};
255
256static const struct iio_chan_spec mcp472x_channel[] = {
257	[MCP4725] = {
258		.type		= IIO_VOLTAGE,
259		.indexed	= 1,
260		.output		= 1,
261		.channel	= 0,
262		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
263		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
264		.ext_info	= mcp4725_ext_info,
265	},
266	[MCP4726] = {
267		.type		= IIO_VOLTAGE,
268		.indexed	= 1,
269		.output		= 1,
270		.channel	= 0,
271		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
272		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
273		.ext_info	= mcp4726_ext_info,
274	},
275};
276
277static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
278{
279	struct mcp4725_data *data = iio_priv(indio_dev);
280	u8 outbuf[2];
281	int ret;
282
283	if (val >= (1 << 12) || val < 0)
284		return -EINVAL;
285
286	outbuf[0] = (val >> 8) & 0xf;
287	outbuf[1] = val & 0xff;
288
289	ret = i2c_master_send(data->client, outbuf, 2);
290	if (ret < 0)
291		return ret;
292	else if (ret != 2)
293		return -EIO;
294	else
295		return 0;
296}
297
298static int mcp4726_set_cfg(struct iio_dev *indio_dev)
299{
300	struct mcp4725_data *data = iio_priv(indio_dev);
301	u8 outbuf[3];
302	int ret;
303
304	outbuf[0] = 0x40;
305	outbuf[0] |= data->ref_mode << 3;
306	if (data->powerdown)
307		outbuf[0] |= data->powerdown << 1;
308	outbuf[1] = data->dac_value >> 4;
309	outbuf[2] = (data->dac_value & 0xf) << 4;
310
311	ret = i2c_master_send(data->client, outbuf, 3);
312	if (ret < 0)
313		return ret;
314	else if (ret != 3)
315		return -EIO;
316	else
317		return 0;
318}
319
320static int mcp4725_read_raw(struct iio_dev *indio_dev,
321			   struct iio_chan_spec const *chan,
322			   int *val, int *val2, long mask)
323{
324	struct mcp4725_data *data = iio_priv(indio_dev);
325	int ret;
326
327	switch (mask) {
328	case IIO_CHAN_INFO_RAW:
329		*val = data->dac_value;
330		return IIO_VAL_INT;
331	case IIO_CHAN_INFO_SCALE:
332		if (data->ref_mode == MCP472X_REF_VDD)
333			ret = regulator_get_voltage(data->vdd_reg);
334		else
335			ret = regulator_get_voltage(data->vref_reg);
336
337		if (ret < 0)
338			return ret;
339
340		*val = ret / 1000;
341		*val2 = 12;
342		return IIO_VAL_FRACTIONAL_LOG2;
343	}
344	return -EINVAL;
345}
346
347static int mcp4725_write_raw(struct iio_dev *indio_dev,
348			       struct iio_chan_spec const *chan,
349			       int val, int val2, long mask)
350{
351	struct mcp4725_data *data = iio_priv(indio_dev);
352	int ret;
353
354	switch (mask) {
355	case IIO_CHAN_INFO_RAW:
356		ret = mcp4725_set_value(indio_dev, val);
357		data->dac_value = val;
358		break;
359	default:
360		ret = -EINVAL;
361		break;
362	}
363
364	return ret;
365}
366
367static const struct iio_info mcp4725_info = {
368	.read_raw = mcp4725_read_raw,
369	.write_raw = mcp4725_write_raw,
370	.attrs = &mcp4725_attribute_group,
371};
372
373static int mcp4725_probe_dt(struct device *dev,
374			    struct mcp4725_platform_data *pdata)
375{
376	/* check if is the vref-supply defined */
377	pdata->use_vref = device_property_read_bool(dev, "vref-supply");
378	pdata->vref_buffered =
379		device_property_read_bool(dev, "microchip,vref-buffered");
380
381	return 0;
382}
383
384static int mcp4725_probe(struct i2c_client *client)
385{
386	const struct i2c_device_id *id = i2c_client_get_device_id(client);
387	struct mcp4725_data *data;
388	struct iio_dev *indio_dev;
389	struct mcp4725_platform_data *pdata, pdata_dt;
390	u8 inbuf[4];
391	u8 pd;
392	u8 ref;
393	int err;
394
395	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
396	if (indio_dev == NULL)
397		return -ENOMEM;
398	data = iio_priv(indio_dev);
399	i2c_set_clientdata(client, indio_dev);
400	data->client = client;
401	if (dev_fwnode(&client->dev))
402		data->id = (uintptr_t)device_get_match_data(&client->dev);
403	else
404		data->id = id->driver_data;
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 (data->id == MCP4725 && 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 = &mcp472x_channel[id->driver_data];
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, data->id == MCP4725 ? 3 : 4);
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 (data->id == MCP4726)
474		ref = (inbuf[3] >> 3) & 0x3;
475
476	if (data->id == MCP4726 && 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
491err_disable_vref_reg:
492	if (data->vref_reg)
493		regulator_disable(data->vref_reg);
494
495err_disable_vdd_reg:
496	regulator_disable(data->vdd_reg);
497
498	return err;
499}
500
501static 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
513static const struct i2c_device_id mcp4725_id[] = {
514	{ "mcp4725", MCP4725 },
515	{ "mcp4726", MCP4726 },
516	{ }
517};
518MODULE_DEVICE_TABLE(i2c, mcp4725_id);
519
520static const struct of_device_id mcp4725_of_match[] = {
521	{
522		.compatible = "microchip,mcp4725",
523		.data = (void *)MCP4725
524	},
525	{
526		.compatible = "microchip,mcp4726",
527		.data = (void *)MCP4726
528	},
529	{ }
530};
531MODULE_DEVICE_TABLE(of, mcp4725_of_match);
532
533static struct i2c_driver mcp4725_driver = {
534	.driver = {
535		.name	= MCP4725_DRV_NAME,
536		.of_match_table = mcp4725_of_match,
537		.pm	= pm_sleep_ptr(&mcp4725_pm_ops),
538	},
539	.probe		= mcp4725_probe,
540	.remove		= mcp4725_remove,
541	.id_table	= mcp4725_id,
542};
543module_i2c_driver(mcp4725_driver);
544
545MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
546MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
547MODULE_LICENSE("GPL");
548