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