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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
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
32enum max5821_device_ids {
33 ID_MAX5821,
34};
35
36struct 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
45static const char * const max5821_powerdown_modes[] = {
46 "three_state",
47 "1kohm_to_gnd",
48 "100kohm_to_gnd",
49};
50
51enum {
52 MAX5821_THREE_STATE,
53 MAX5821_1KOHM_TO_GND,
54 MAX5821_100KOHM_TO_GND
55};
56
57static 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
65static 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
76static 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
83static 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
93static 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
113static 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
135static 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
157static const struct iio_chan_spec max5821_channels[] = {
158 MAX5821_CHANNEL(0),
159 MAX5821_CHANNEL(1)
160};
161
162static const u8 max5821_read_dac_command[] = {
163 MAX5821_READ_DAC_A_COMMAND,
164 MAX5821_READ_DAC_B_COMMAND
165};
166
167static const u8 max5821_load_dac_command[] = {
168 MAX5821_LOAD_DAC_A_IN_REG_B,
169 MAX5821_LOAD_DAC_B_IN_REG_A
170};
171
172static 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
213static 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
240static 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
258static 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
274static 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
284static 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
294static 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
299
300static const struct iio_info max5821_info = {
301 .read_raw = max5821_read_raw,
302 .write_raw = max5821_write_raw,
303 .driver_module = THIS_MODULE,
304};
305
306static int max5821_probe(struct i2c_client *client,
307 const struct i2c_device_id *id)
308{
309 struct max5821_data *data;
310 struct iio_dev *indio_dev;
311 u32 tmp;
312 int ret;
313
314 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
315 if (!indio_dev)
316 return -ENOMEM;
317 data = iio_priv(indio_dev);
318 i2c_set_clientdata(client, indio_dev);
319 data->client = client;
320 mutex_init(&data->lock);
321
322
323 for (tmp = 0; tmp < MAX5821_MAX_DAC_CHANNELS; tmp++) {
324 data->powerdown[tmp] = true;
325 data->powerdown_mode[tmp] = MAX5821_100KOHM_TO_GND;
326 }
327
328 data->vref_reg = devm_regulator_get(&client->dev, "vref");
329 if (IS_ERR(data->vref_reg)) {
330 ret = PTR_ERR(data->vref_reg);
331 dev_err(&client->dev,
332 "Failed to get vref regulator: %d\n", ret);
333 goto error_free_reg;
334 }
335
336 ret = regulator_enable(data->vref_reg);
337 if (ret) {
338 dev_err(&client->dev,
339 "Failed to enable vref regulator: %d\n", ret);
340 goto error_free_reg;
341 }
342
343 ret = regulator_get_voltage(data->vref_reg);
344 if (ret < 0) {
345 dev_err(&client->dev,
346 "Failed to get voltage on regulator: %d\n", ret);
347 goto error_disable_reg;
348 }
349
350 data->vref_mv = ret / 1000;
351
352 indio_dev->name = id->name;
353 indio_dev->dev.parent = &client->dev;
354 indio_dev->num_channels = ARRAY_SIZE(max5821_channels);
355 indio_dev->channels = max5821_channels;
356 indio_dev->modes = INDIO_DIRECT_MODE;
357 indio_dev->info = &max5821_info;
358
359 return iio_device_register(indio_dev);
360
361error_disable_reg:
362 regulator_disable(data->vref_reg);
363
364error_free_reg:
365
366 return ret;
367}
368
369static int max5821_remove(struct i2c_client *client)
370{
371 struct iio_dev *indio_dev = i2c_get_clientdata(client);
372 struct max5821_data *data = iio_priv(indio_dev);
373
374 iio_device_unregister(indio_dev);
375 regulator_disable(data->vref_reg);
376
377 return 0;
378}
379
380static const struct i2c_device_id max5821_id[] = {
381 { "max5821", ID_MAX5821 },
382 { }
383};
384MODULE_DEVICE_TABLE(i2c, max5821_id);
385
386static const struct of_device_id max5821_of_match[] = {
387 { .compatible = "maxim,max5821" },
388 { }
389};
390MODULE_DEVICE_TABLE(of, max5821_of_match);
391
392static struct i2c_driver max5821_driver = {
393 .driver = {
394 .name = "max5821",
395 .pm = MAX5821_PM_OPS,
396 },
397 .probe = max5821_probe,
398 .remove = max5821_remove,
399 .id_table = max5821_id,
400};
401module_i2c_driver(max5821_driver);
402
403MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
404MODULE_DESCRIPTION("MAX5821 DAC");
405MODULE_LICENSE("GPL v2");
406
