max5821.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * iio/dac/max5821.c
  4  * Copyright (C) 2014 Philippe Reynes
  5  */
  6
  7#include <linux/kernel.h>
  8#include <linux/module.h>
  9#include <linux/i2c.h>
 10#include <linux/iio/iio.h>
 11#include <linux/regulator/consumer.h>
 12
 13#define MAX5821_MAX_DAC_CHANNELS		2
 14
 15/* command bytes */
 16#define MAX5821_LOAD_DAC_A_IN_REG_B		0x00
 17#define MAX5821_LOAD_DAC_B_IN_REG_A		0x10
 18#define MAX5821_EXTENDED_COMMAND_MODE		0xf0
 19#define MAX5821_READ_DAC_A_COMMAND		0xf1
 20#define MAX5821_READ_DAC_B_COMMAND		0xf2
 21
 22#define MAX5821_EXTENDED_POWER_UP		0x00
 23#define MAX5821_EXTENDED_POWER_DOWN_MODE0	0x01
 24#define MAX5821_EXTENDED_POWER_DOWN_MODE1	0x02
 25#define MAX5821_EXTENDED_POWER_DOWN_MODE2	0x03
 26#define MAX5821_EXTENDED_DAC_A			0x04
 27#define MAX5821_EXTENDED_DAC_B			0x08
 28
 29enum max5821_device_ids {
 30	ID_MAX5821,
 31};
 32
 33struct max5821_data {
 34	struct i2c_client	*client;
 35	unsigned short		vref_mv;
 36	bool			powerdown[MAX5821_MAX_DAC_CHANNELS];
 37	u8			powerdown_mode[MAX5821_MAX_DAC_CHANNELS];
 38	struct mutex		lock;
 39};
 40
 41static const char * const max5821_powerdown_modes[] = {
 42	"three_state",
 43	"1kohm_to_gnd",
 44	"100kohm_to_gnd",
 45};
 46
 47enum {
 48	MAX5821_THREE_STATE,
 49	MAX5821_1KOHM_TO_GND,
 50	MAX5821_100KOHM_TO_GND
 51};
 52
 53static int max5821_get_powerdown_mode(struct iio_dev *indio_dev,
 54				      const struct iio_chan_spec *chan)
 55{
 56	struct max5821_data *st = iio_priv(indio_dev);
 57
 58	return st->powerdown_mode[chan->channel];
 59}
 60
 61static int max5821_set_powerdown_mode(struct iio_dev *indio_dev,
 62				      const struct iio_chan_spec *chan,
 63				      unsigned int mode)
 64{
 65	struct max5821_data *st = iio_priv(indio_dev);
 66
 67	st->powerdown_mode[chan->channel] = mode;
 68
 69	return 0;
 70}
 71
 72static const struct iio_enum max5821_powerdown_mode_enum = {
 73	.items = max5821_powerdown_modes,
 74	.num_items = ARRAY_SIZE(max5821_powerdown_modes),
 75	.get = max5821_get_powerdown_mode,
 76	.set = max5821_set_powerdown_mode,
 77};
 78
 79static ssize_t max5821_read_dac_powerdown(struct iio_dev *indio_dev,
 80					  uintptr_t private,
 81					  const struct iio_chan_spec *chan,
 82					  char *buf)
 83{
 84	struct max5821_data *st = iio_priv(indio_dev);
 85
 86	return sysfs_emit(buf, "%d\n", st->powerdown[chan->channel]);
 87}
 88
 89static int max5821_sync_powerdown_mode(struct max5821_data *data,
 90				       const struct iio_chan_spec *chan)
 91{
 92	u8 outbuf[2];
 93
 94	outbuf[0] = MAX5821_EXTENDED_COMMAND_MODE;
 95
 96	if (chan->channel == 0)
 97		outbuf[1] = MAX5821_EXTENDED_DAC_A;
 98	else
 99		outbuf[1] = MAX5821_EXTENDED_DAC_B;
100
101	if (data->powerdown[chan->channel])
102		outbuf[1] |= data->powerdown_mode[chan->channel] + 1;
103	else
104		outbuf[1] |= MAX5821_EXTENDED_POWER_UP;
105
106	return i2c_master_send(data->client, outbuf, 2);
107}
108
109static ssize_t max5821_write_dac_powerdown(struct iio_dev *indio_dev,
110					   uintptr_t private,
111					   const struct iio_chan_spec *chan,
112					   const char *buf, size_t len)
113{
114	struct max5821_data *data = iio_priv(indio_dev);
115	bool powerdown;
116	int ret;
117
118	ret = kstrtobool(buf, &powerdown);
119	if (ret)
120		return ret;
121
122	data->powerdown[chan->channel] = powerdown;
123
124	ret = max5821_sync_powerdown_mode(data, chan);
125	if (ret < 0)
126		return ret;
127
128	return len;
129}
130
131static const struct iio_chan_spec_ext_info max5821_ext_info[] = {
132	{
133		.name = "powerdown",
134		.read = max5821_read_dac_powerdown,
135		.write = max5821_write_dac_powerdown,
136		.shared = IIO_SEPARATE,
137	},
138	IIO_ENUM("powerdown_mode", IIO_SEPARATE, &max5821_powerdown_mode_enum),
139	IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &max5821_powerdown_mode_enum),
140	{ }
141};
142
143#define MAX5821_CHANNEL(chan) {					\
144	.type = IIO_VOLTAGE,					\
145	.indexed = 1,						\
146	.output = 1,						\
147	.channel = (chan),					\
148	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
149	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),	\
150	.ext_info = max5821_ext_info,				\
151}
152
153static const struct iio_chan_spec max5821_channels[] = {
154	MAX5821_CHANNEL(0),
155	MAX5821_CHANNEL(1)
156};
157
158static const u8 max5821_read_dac_command[] = {
159	MAX5821_READ_DAC_A_COMMAND,
160	MAX5821_READ_DAC_B_COMMAND
161};
162
163static const u8 max5821_load_dac_command[] = {
164	MAX5821_LOAD_DAC_A_IN_REG_B,
165	MAX5821_LOAD_DAC_B_IN_REG_A
166};
167
168static int max5821_get_value(struct iio_dev *indio_dev,
169			     int *val, int channel)
170{
171	struct max5821_data *data = iio_priv(indio_dev);
172	struct i2c_client *client = data->client;
173	u8 outbuf[1];
174	u8 inbuf[2];
175	int ret;
176
177	if ((channel != 0) && (channel != 1))
178		return -EINVAL;
179
180	outbuf[0] = max5821_read_dac_command[channel];
181
182	mutex_lock(&data->lock);
183
184	ret = i2c_master_send(client, outbuf, 1);
185	if (ret < 0) {
186		mutex_unlock(&data->lock);
187		return ret;
188	} else if (ret != 1) {
189		mutex_unlock(&data->lock);
190		return -EIO;
191	}
192
193	ret = i2c_master_recv(client, inbuf, 2);
194	if (ret < 0) {
195		mutex_unlock(&data->lock);
196		return ret;
197	} else if (ret != 2) {
198		mutex_unlock(&data->lock);
199		return -EIO;
200	}
201
202	mutex_unlock(&data->lock);
203
204	*val = ((inbuf[0] & 0x0f) << 6) | (inbuf[1] >> 2);
205
206	return IIO_VAL_INT;
207}
208
209static int max5821_set_value(struct iio_dev *indio_dev,
210			     int val, int channel)
211{
212	struct max5821_data *data = iio_priv(indio_dev);
213	struct i2c_client *client = data->client;
214	u8 outbuf[2];
215	int ret;
216
217	if ((val < 0) || (val > 1023))
218		return -EINVAL;
219
220	if ((channel != 0) && (channel != 1))
221		return -EINVAL;
222
223	outbuf[0] = max5821_load_dac_command[channel];
224	outbuf[0] |= val >> 6;
225	outbuf[1] = (val & 0x3f) << 2;
226
227	ret = i2c_master_send(client, outbuf, 2);
228	if (ret < 0)
229		return ret;
230	else if (ret != 2)
231		return -EIO;
232	else
233		return 0;
234}
235
236static int max5821_read_raw(struct iio_dev *indio_dev,
237			   struct iio_chan_spec const *chan,
238			   int *val, int *val2, long mask)
239{
240	struct max5821_data *data = iio_priv(indio_dev);
241
242	switch (mask) {
243	case IIO_CHAN_INFO_RAW:
244		return max5821_get_value(indio_dev, val, chan->channel);
245	case IIO_CHAN_INFO_SCALE:
246		*val = data->vref_mv;
247		*val2 = 10;
248		return IIO_VAL_FRACTIONAL_LOG2;
249	default:
250		return -EINVAL;
251	}
252}
253
254static int max5821_write_raw(struct iio_dev *indio_dev,
255			     struct iio_chan_spec const *chan,
256			     int val, int val2, long mask)
257{
258	if (val2 != 0)
259		return -EINVAL;
260
261	switch (mask) {
262	case IIO_CHAN_INFO_RAW:
263		return max5821_set_value(indio_dev, val, chan->channel);
264	default:
265		return -EINVAL;
266	}
267}
268
269static int max5821_suspend(struct device *dev)
270{
271	u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
272			 MAX5821_EXTENDED_DAC_A |
273			 MAX5821_EXTENDED_DAC_B |
274			 MAX5821_EXTENDED_POWER_DOWN_MODE2 };
275
276	return i2c_master_send(to_i2c_client(dev), outbuf, 2);
277}
278
279static int max5821_resume(struct device *dev)
280{
281	u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
282			 MAX5821_EXTENDED_DAC_A |
283			 MAX5821_EXTENDED_DAC_B |
284			 MAX5821_EXTENDED_POWER_UP };
285
286	return i2c_master_send(to_i2c_client(dev), outbuf, 2);
287}
288
289static DEFINE_SIMPLE_DEV_PM_OPS(max5821_pm_ops, max5821_suspend,
290				max5821_resume);
291
292static const struct iio_info max5821_info = {
293	.read_raw = max5821_read_raw,
294	.write_raw = max5821_write_raw,
295};
296
297static int max5821_probe(struct i2c_client *client)
298{
299	const struct i2c_device_id *id = i2c_client_get_device_id(client);
300	struct max5821_data *data;
301	struct iio_dev *indio_dev;
302	u32 tmp;
303	int ret;
304
305	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
306	if (!indio_dev)
307		return -ENOMEM;
308	data = iio_priv(indio_dev);
309	data->client = client;
310	mutex_init(&data->lock);
311
312	/* max5821 start in powerdown mode 100Kohm to ground */
313	for (tmp = 0; tmp < MAX5821_MAX_DAC_CHANNELS; tmp++) {
314		data->powerdown[tmp] = true;
315		data->powerdown_mode[tmp] = MAX5821_100KOHM_TO_GND;
316	}
317
318	ret = devm_regulator_get_enable_read_voltage(&client->dev, "vref");
319	if (ret)
320		return dev_err_probe(&client->dev, ret,
321				     "Failed to get vref regulator voltage\n");
322
323	data->vref_mv = ret / 1000;
324
325	indio_dev->name = id->name;
326	indio_dev->num_channels = ARRAY_SIZE(max5821_channels);
327	indio_dev->channels = max5821_channels;
328	indio_dev->modes = INDIO_DIRECT_MODE;
329	indio_dev->info = &max5821_info;
330
331	return devm_iio_device_register(&client->dev, indio_dev);
332}
333
334static const struct i2c_device_id max5821_id[] = {
335	{ "max5821", ID_MAX5821 },
336	{ }
337};
338MODULE_DEVICE_TABLE(i2c, max5821_id);
339
340static const struct of_device_id max5821_of_match[] = {
341	{ .compatible = "maxim,max5821" },
342	{ }
343};
344MODULE_DEVICE_TABLE(of, max5821_of_match);
345
346static struct i2c_driver max5821_driver = {
347	.driver = {
348		.name	= "max5821",
349		.of_match_table = max5821_of_match,
350		.pm     = pm_sleep_ptr(&max5821_pm_ops),
351	},
352	.probe		= max5821_probe,
353	.id_table	= max5821_id,
354};
355module_i2c_driver(max5821_driver);
356
357MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
358MODULE_DESCRIPTION("MAX5821 DAC");
359MODULE_LICENSE("GPL v2");