1 /*
2 * iio/dac/max5821.c
3 * Copyright (C) 2014 Philippe Reynes
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 */
9
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/i2c.h>
13 #include <linux/iio/iio.h>
14 #include <linux/regulator/consumer.h>
15
16 #define MAX5821_MAX_DAC_CHANNELS 2
17
18 /* command bytes */
19 #define MAX5821_LOAD_DAC_A_IN_REG_B 0x00
20 #define MAX5821_LOAD_DAC_B_IN_REG_A 0x10
21 #define MAX5821_EXTENDED_COMMAND_MODE 0xf0
22 #define MAX5821_READ_DAC_A_COMMAND 0xf1
23 #define MAX5821_READ_DAC_B_COMMAND 0xf2
24
25 #define MAX5821_EXTENDED_POWER_UP 0x00
26 #define MAX5821_EXTENDED_POWER_DOWN_MODE0 0x01
27 #define MAX5821_EXTENDED_POWER_DOWN_MODE1 0x02
28 #define MAX5821_EXTENDED_POWER_DOWN_MODE2 0x03
29 #define MAX5821_EXTENDED_DAC_A 0x04
30 #define MAX5821_EXTENDED_DAC_B 0x08
31
32 enum max5821_device_ids {
33 ID_MAX5821,
34 };
35
36 struct max5821_data {
37 struct i2c_client *client;
38 struct regulator *vref_reg;
39 unsigned short vref_mv;
40 bool powerdown[MAX5821_MAX_DAC_CHANNELS];
41 u8 powerdown_mode[MAX5821_MAX_DAC_CHANNELS];
42 struct mutex lock;
43 };
44
45 static const char * const max5821_powerdown_modes[] = {
46 "three_state",
47 "1kohm_to_gnd",
48 "100kohm_to_gnd",
49 };
50
51 enum {
52 MAX5821_THREE_STATE,
53 MAX5821_1KOHM_TO_GND,
54 MAX5821_100KOHM_TO_GND
55 };
56
max5821_get_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan)57 static int max5821_get_powerdown_mode(struct iio_dev *indio_dev,
58 const struct iio_chan_spec *chan)
59 {
60 struct max5821_data *st = iio_priv(indio_dev);
61
62 return st->powerdown_mode[chan->channel];
63 }
64
max5821_set_powerdown_mode(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,unsigned int mode)65 static int max5821_set_powerdown_mode(struct iio_dev *indio_dev,
66 const struct iio_chan_spec *chan,
67 unsigned int mode)
68 {
69 struct max5821_data *st = iio_priv(indio_dev);
70
71 st->powerdown_mode[chan->channel] = mode;
72
73 return 0;
74 }
75
76 static const struct iio_enum max5821_powerdown_mode_enum = {
77 .items = max5821_powerdown_modes,
78 .num_items = ARRAY_SIZE(max5821_powerdown_modes),
79 .get = max5821_get_powerdown_mode,
80 .set = max5821_set_powerdown_mode,
81 };
82
max5821_read_dac_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,char * buf)83 static ssize_t max5821_read_dac_powerdown(struct iio_dev *indio_dev,
84 uintptr_t private,
85 const struct iio_chan_spec *chan,
86 char *buf)
87 {
88 struct max5821_data *st = iio_priv(indio_dev);
89
90 return sprintf(buf, "%d\n", st->powerdown[chan->channel]);
91 }
92
max5821_sync_powerdown_mode(struct max5821_data * data,const struct iio_chan_spec * chan)93 static int max5821_sync_powerdown_mode(struct max5821_data *data,
94 const struct iio_chan_spec *chan)
95 {
96 u8 outbuf[2];
97
98 outbuf[0] = MAX5821_EXTENDED_COMMAND_MODE;
99
100 if (chan->channel == 0)
101 outbuf[1] = MAX5821_EXTENDED_DAC_A;
102 else
103 outbuf[1] = MAX5821_EXTENDED_DAC_B;
104
105 if (data->powerdown[chan->channel])
106 outbuf[1] |= data->powerdown_mode[chan->channel] + 1;
107 else
108 outbuf[1] |= MAX5821_EXTENDED_POWER_UP;
109
110 return i2c_master_send(data->client, outbuf, 2);
111 }
112
max5821_write_dac_powerdown(struct iio_dev * indio_dev,uintptr_t private,const struct iio_chan_spec * chan,const char * buf,size_t len)113 static ssize_t max5821_write_dac_powerdown(struct iio_dev *indio_dev,
114 uintptr_t private,
115 const struct iio_chan_spec *chan,
116 const char *buf, size_t len)
117 {
118 struct max5821_data *data = iio_priv(indio_dev);
119 bool powerdown;
120 int ret;
121
122 ret = strtobool(buf, &powerdown);
123 if (ret)
124 return ret;
125
126 data->powerdown[chan->channel] = powerdown;
127
128 ret = max5821_sync_powerdown_mode(data, chan);
129 if (ret < 0)
130 return ret;
131
132 return len;
133 }
134
135 static const struct iio_chan_spec_ext_info max5821_ext_info[] = {
136 {
137 .name = "powerdown",
138 .read = max5821_read_dac_powerdown,
139 .write = max5821_write_dac_powerdown,
140 .shared = IIO_SEPARATE,
141 },
142 IIO_ENUM("powerdown_mode", IIO_SEPARATE, &max5821_powerdown_mode_enum),
143 IIO_ENUM_AVAILABLE("powerdown_mode", &max5821_powerdown_mode_enum),
144 { },
145 };
146
147 #define MAX5821_CHANNEL(chan) { \
148 .type = IIO_VOLTAGE, \
149 .indexed = 1, \
150 .output = 1, \
151 .channel = (chan), \
152 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
153 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE), \
154 .ext_info = max5821_ext_info, \
155 }
156
157 static const struct iio_chan_spec max5821_channels[] = {
158 MAX5821_CHANNEL(0),
159 MAX5821_CHANNEL(1)
160 };
161
162 static const u8 max5821_read_dac_command[] = {
163 MAX5821_READ_DAC_A_COMMAND,
164 MAX5821_READ_DAC_B_COMMAND
165 };
166
167 static const u8 max5821_load_dac_command[] = {
168 MAX5821_LOAD_DAC_A_IN_REG_B,
169 MAX5821_LOAD_DAC_B_IN_REG_A
170 };
171
max5821_get_value(struct iio_dev * indio_dev,int * val,int channel)172 static int max5821_get_value(struct iio_dev *indio_dev,
173 int *val, int channel)
174 {
175 struct max5821_data *data = iio_priv(indio_dev);
176 struct i2c_client *client = data->client;
177 u8 outbuf[1];
178 u8 inbuf[2];
179 int ret;
180
181 if ((channel != 0) && (channel != 1))
182 return -EINVAL;
183
184 outbuf[0] = max5821_read_dac_command[channel];
185
186 mutex_lock(&data->lock);
187
188 ret = i2c_master_send(client, outbuf, 1);
189 if (ret < 0) {
190 mutex_unlock(&data->lock);
191 return ret;
192 } else if (ret != 1) {
193 mutex_unlock(&data->lock);
194 return -EIO;
195 }
196
197 ret = i2c_master_recv(client, inbuf, 2);
198 if (ret < 0) {
199 mutex_unlock(&data->lock);
200 return ret;
201 } else if (ret != 2) {
202 mutex_unlock(&data->lock);
203 return -EIO;
204 }
205
206 mutex_unlock(&data->lock);
207
208 *val = ((inbuf[0] & 0x0f) << 6) | (inbuf[1] >> 2);
209
210 return IIO_VAL_INT;
211 }
212
max5821_set_value(struct iio_dev * indio_dev,int val,int channel)213 static int max5821_set_value(struct iio_dev *indio_dev,
214 int val, int channel)
215 {
216 struct max5821_data *data = iio_priv(indio_dev);
217 struct i2c_client *client = data->client;
218 u8 outbuf[2];
219 int ret;
220
221 if ((val < 0) || (val > 1023))
222 return -EINVAL;
223
224 if ((channel != 0) && (channel != 1))
225 return -EINVAL;
226
227 outbuf[0] = max5821_load_dac_command[channel];
228 outbuf[0] |= val >> 6;
229 outbuf[1] = (val & 0x3f) << 2;
230
231 ret = i2c_master_send(client, outbuf, 2);
232 if (ret < 0)
233 return ret;
234 else if (ret != 2)
235 return -EIO;
236 else
237 return 0;
238 }
239
max5821_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)240 static int max5821_read_raw(struct iio_dev *indio_dev,
241 struct iio_chan_spec const *chan,
242 int *val, int *val2, long mask)
243 {
244 struct max5821_data *data = iio_priv(indio_dev);
245
246 switch (mask) {
247 case IIO_CHAN_INFO_RAW:
248 return max5821_get_value(indio_dev, val, chan->channel);
249 case IIO_CHAN_INFO_SCALE:
250 *val = data->vref_mv;
251 *val2 = 10;
252 return IIO_VAL_FRACTIONAL_LOG2;
253 default:
254 return -EINVAL;
255 }
256 }
257
max5821_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)258 static int max5821_write_raw(struct iio_dev *indio_dev,
259 struct iio_chan_spec const *chan,
260 int val, int val2, long mask)
261 {
262 if (val2 != 0)
263 return -EINVAL;
264
265 switch (mask) {
266 case IIO_CHAN_INFO_RAW:
267 return max5821_set_value(indio_dev, val, chan->channel);
268 default:
269 return -EINVAL;
270 }
271 }
272
273 #ifdef CONFIG_PM_SLEEP
max5821_suspend(struct device * dev)274 static int max5821_suspend(struct device *dev)
275 {
276 u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
277 MAX5821_EXTENDED_DAC_A |
278 MAX5821_EXTENDED_DAC_B |
279 MAX5821_EXTENDED_POWER_DOWN_MODE2 };
280
281 return i2c_master_send(to_i2c_client(dev), outbuf, 2);
282 }
283
max5821_resume(struct device * dev)284 static int max5821_resume(struct device *dev)
285 {
286 u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
287 MAX5821_EXTENDED_DAC_A |
288 MAX5821_EXTENDED_DAC_B |
289 MAX5821_EXTENDED_POWER_UP };
290
291 return i2c_master_send(to_i2c_client(dev), outbuf, 2);
292 }
293
294 static SIMPLE_DEV_PM_OPS(max5821_pm_ops, max5821_suspend, max5821_resume);
295 #define MAX5821_PM_OPS (&max5821_pm_ops)
296 #else
297 #define MAX5821_PM_OPS NULL
298 #endif /* CONFIG_PM_SLEEP */
299
300 static const struct iio_info max5821_info = {
301 .read_raw = max5821_read_raw,
302 .write_raw = max5821_write_raw,
303 };
304
max5821_probe(struct i2c_client * client,const struct i2c_device_id * id)305 static int max5821_probe(struct i2c_client *client,
306 const struct i2c_device_id *id)
307 {
308 struct max5821_data *data;
309 struct iio_dev *indio_dev;
310 u32 tmp;
311 int ret;
312
313 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
314 if (!indio_dev)
315 return -ENOMEM;
316 data = iio_priv(indio_dev);
317 i2c_set_clientdata(client, indio_dev);
318 data->client = client;
319 mutex_init(&data->lock);
320
321 /* max5821 start in powerdown mode 100Kohm to ground */
322 for (tmp = 0; tmp < MAX5821_MAX_DAC_CHANNELS; tmp++) {
323 data->powerdown[tmp] = true;
324 data->powerdown_mode[tmp] = MAX5821_100KOHM_TO_GND;
325 }
326
327 data->vref_reg = devm_regulator_get(&client->dev, "vref");
328 if (IS_ERR(data->vref_reg)) {
329 ret = PTR_ERR(data->vref_reg);
330 dev_err(&client->dev,
331 "Failed to get vref regulator: %d\n", ret);
332 goto error_free_reg;
333 }
334
335 ret = regulator_enable(data->vref_reg);
336 if (ret) {
337 dev_err(&client->dev,
338 "Failed to enable vref regulator: %d\n", ret);
339 goto error_free_reg;
340 }
341
342 ret = regulator_get_voltage(data->vref_reg);
343 if (ret < 0) {
344 dev_err(&client->dev,
345 "Failed to get voltage on regulator: %d\n", ret);
346 goto error_disable_reg;
347 }
348
349 data->vref_mv = ret / 1000;
350
351 indio_dev->name = id->name;
352 indio_dev->dev.parent = &client->dev;
353 indio_dev->num_channels = ARRAY_SIZE(max5821_channels);
354 indio_dev->channels = max5821_channels;
355 indio_dev->modes = INDIO_DIRECT_MODE;
356 indio_dev->info = &max5821_info;
357
358 return iio_device_register(indio_dev);
359
360 error_disable_reg:
361 regulator_disable(data->vref_reg);
362
363 error_free_reg:
364
365 return ret;
366 }
367
max5821_remove(struct i2c_client * client)368 static int max5821_remove(struct i2c_client *client)
369 {
370 struct iio_dev *indio_dev = i2c_get_clientdata(client);
371 struct max5821_data *data = iio_priv(indio_dev);
372
373 iio_device_unregister(indio_dev);
374 regulator_disable(data->vref_reg);
375
376 return 0;
377 }
378
379 static const struct i2c_device_id max5821_id[] = {
380 { "max5821", ID_MAX5821 },
381 { }
382 };
383 MODULE_DEVICE_TABLE(i2c, max5821_id);
384
385 static const struct of_device_id max5821_of_match[] = {
386 { .compatible = "maxim,max5821" },
387 { }
388 };
389 MODULE_DEVICE_TABLE(of, max5821_of_match);
390
391 static struct i2c_driver max5821_driver = {
392 .driver = {
393 .name = "max5821",
394 .of_match_table = max5821_of_match,
395 .pm = MAX5821_PM_OPS,
396 },
397 .probe = max5821_probe,
398 .remove = max5821_remove,
399 .id_table = max5821_id,
400 };
401 module_i2c_driver(max5821_driver);
402
403 MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
404 MODULE_DESCRIPTION("MAX5821 DAC");
405 MODULE_LICENSE("GPL v2");
406