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_chip_info {
34	const struct iio_chan_spec *chan_spec;
35	u8 dac_reg_offset;
36	bool use_ext_ref_voltage;
37};
38
39struct 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
50static 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
69static 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}
88static DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend,
89				mcp4725_resume);
90
91static 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
142static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
143
144static struct attribute *mcp4725_attributes[] = {
145	&iio_dev_attr_store_eeprom.dev_attr.attr,
146	NULL,
147};
148
149static const struct attribute_group mcp4725_attribute_group = {
150	.attrs = mcp4725_attributes,
151};
152
153static const char * const mcp4725_powerdown_modes[] = {
154	"1kohm_to_gnd",
155	"100kohm_to_gnd",
156	"500kohm_to_gnd"
157};
158
159static const char * const mcp4726_powerdown_modes[] = {
160	"1kohm_to_gnd",
161	"125kohm_to_gnd",
162	"640kohm_to_gnd"
163};
164
165static 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
173static 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
183static 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
191static 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
213enum chip_id {
214	MCP4725,
215	MCP4726,
216};
217
218static 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
233static 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
247static 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
261static 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
282static 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
303static 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
325static 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
352static 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
372static 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
378static 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
389static 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
494err_disable_vref_reg:
495	if (data->vref_reg)
496		regulator_disable(data->vref_reg);
497
498err_disable_vdd_reg:
499	regulator_disable(data->vdd_reg);
500
501	return err;
502}
503
504static 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
516static 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
522static const struct mcp4725_chip_info mcp4726 = {
523	.chan_spec = &mcp472x_channel[MCP4726],
524	.dac_reg_offset = 4,
525};
526
527static const struct i2c_device_id mcp4725_id[] = {
528	{ "mcp4725", (kernel_ulong_t)&mcp4725 },
529	{ "mcp4726", (kernel_ulong_t)&mcp4726 },
530	{ }
531};
532MODULE_DEVICE_TABLE(i2c, mcp4725_id);
533
534static 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};
545MODULE_DEVICE_TABLE(of, mcp4725_of_match);
546
547static 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};
557module_i2c_driver(mcp4725_driver);
558
559MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
560MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
561MODULE_LICENSE("GPL");
562