xref: /linux/drivers/iio/dac/max5821.c (revision 13845bdc869f136f92ad3d40ea09b867bb4ce467)
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 
29 enum max5821_device_ids {
30 	ID_MAX5821,
31 };
32 
33 struct 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 
41 static const char * const max5821_powerdown_modes[] = {
42 	"three_state",
43 	"1kohm_to_gnd",
44 	"100kohm_to_gnd",
45 };
46 
47 enum {
48 	MAX5821_THREE_STATE,
49 	MAX5821_1KOHM_TO_GND,
50 	MAX5821_100KOHM_TO_GND
51 };
52 
53 static 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 
61 static 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 
72 static 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 
79 static 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 
89 static 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 
109 static 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 
131 static 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 
153 static const struct iio_chan_spec max5821_channels[] = {
154 	MAX5821_CHANNEL(0),
155 	MAX5821_CHANNEL(1)
156 };
157 
158 static const u8 max5821_read_dac_command[] = {
159 	MAX5821_READ_DAC_A_COMMAND,
160 	MAX5821_READ_DAC_B_COMMAND
161 };
162 
163 static const u8 max5821_load_dac_command[] = {
164 	MAX5821_LOAD_DAC_A_IN_REG_B,
165 	MAX5821_LOAD_DAC_B_IN_REG_A
166 };
167 
168 static 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 
209 static 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 
236 static 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 
254 static 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 
269 static 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 
279 static 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 
289 static DEFINE_SIMPLE_DEV_PM_OPS(max5821_pm_ops, max5821_suspend,
290 				max5821_resume);
291 
292 static const struct iio_info max5821_info = {
293 	.read_raw = max5821_read_raw,
294 	.write_raw = max5821_write_raw,
295 };
296 
297 static 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 
334 static const struct i2c_device_id max5821_id[] = {
335 	{ "max5821", ID_MAX5821 },
336 	{ }
337 };
338 MODULE_DEVICE_TABLE(i2c, max5821_id);
339 
340 static const struct of_device_id max5821_of_match[] = {
341 	{ .compatible = "maxim,max5821" },
342 	{ }
343 };
344 MODULE_DEVICE_TABLE(of, max5821_of_match);
345 
346 static 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 };
355 module_i2c_driver(max5821_driver);
356 
357 MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
358 MODULE_DESCRIPTION("MAX5821 DAC");
359 MODULE_LICENSE("GPL v2");
360