1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * mcp4725.c - Support for Microchip MCP4725/6 |
4 | * |
5 | * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net> |
6 | * |
7 | * Based on max517 by Roland Stigge <stigge@antcom.de> |
8 | * |
9 | * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC) |
10 | * (7-bit I2C slave address 0x60, the three LSBs can be configured in |
11 | * hardware) |
12 | */ |
13 | |
14 | #include <linux/module.h> |
15 | #include <linux/i2c.h> |
16 | #include <linux/err.h> |
17 | #include <linux/delay.h> |
18 | #include <linux/regulator/consumer.h> |
19 | #include <linux/mod_devicetable.h> |
20 | #include <linux/property.h> |
21 | |
22 | #include <linux/iio/iio.h> |
23 | #include <linux/iio/sysfs.h> |
24 | |
25 | #include <linux/iio/dac/mcp4725.h> |
26 | |
27 | #define MCP4725_DRV_NAME "mcp4725" |
28 | |
29 | #define MCP472X_REF_VDD 0x00 |
30 | #define MCP472X_REF_VREF_UNBUFFERED 0x02 |
31 | #define MCP472X_REF_VREF_BUFFERED 0x03 |
32 | |
33 | struct mcp4725_chip_info { |
34 | const struct iio_chan_spec *chan_spec; |
35 | u8 dac_reg_offset; |
36 | bool use_ext_ref_voltage; |
37 | }; |
38 | |
39 | struct mcp4725_data { |
40 | struct i2c_client *client; |
41 | unsigned ref_mode; |
42 | bool vref_buffered; |
43 | u16 dac_value; |
44 | bool powerdown; |
45 | unsigned powerdown_mode; |
46 | struct regulator *vdd_reg; |
47 | struct regulator *vref_reg; |
48 | }; |
49 | |
50 | static int mcp4725_suspend(struct device *dev) |
51 | { |
52 | struct mcp4725_data *data = iio_priv(indio_dev: i2c_get_clientdata( |
53 | to_i2c_client(dev))); |
54 | u8 outbuf[2]; |
55 | int ret; |
56 | |
57 | outbuf[0] = (data->powerdown_mode + 1) << 4; |
58 | outbuf[1] = 0; |
59 | data->powerdown = true; |
60 | |
61 | ret = i2c_master_send(client: data->client, buf: outbuf, count: 2); |
62 | if (ret < 0) |
63 | return ret; |
64 | else if (ret != 2) |
65 | return -EIO; |
66 | return 0; |
67 | } |
68 | |
69 | static int mcp4725_resume(struct device *dev) |
70 | { |
71 | struct mcp4725_data *data = iio_priv(indio_dev: i2c_get_clientdata( |
72 | to_i2c_client(dev))); |
73 | u8 outbuf[2]; |
74 | int ret; |
75 | |
76 | /* restore previous DAC value */ |
77 | outbuf[0] = (data->dac_value >> 8) & 0xf; |
78 | outbuf[1] = data->dac_value & 0xff; |
79 | data->powerdown = false; |
80 | |
81 | ret = i2c_master_send(client: data->client, buf: outbuf, count: 2); |
82 | if (ret < 0) |
83 | return ret; |
84 | else if (ret != 2) |
85 | return -EIO; |
86 | return 0; |
87 | } |
88 | static DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, |
89 | mcp4725_resume); |
90 | |
91 | static ssize_t mcp4725_store_eeprom(struct device *dev, |
92 | struct device_attribute *attr, const char *buf, size_t len) |
93 | { |
94 | struct iio_dev *indio_dev = dev_to_iio_dev(dev); |
95 | struct mcp4725_data *data = iio_priv(indio_dev); |
96 | int tries = 20; |
97 | u8 inoutbuf[3]; |
98 | bool state; |
99 | int ret; |
100 | |
101 | ret = kstrtobool(s: buf, res: &state); |
102 | if (ret < 0) |
103 | return ret; |
104 | |
105 | if (!state) |
106 | return 0; |
107 | |
108 | inoutbuf[0] = 0x60; /* write EEPROM */ |
109 | inoutbuf[0] |= data->ref_mode << 3; |
110 | inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0; |
111 | inoutbuf[1] = data->dac_value >> 4; |
112 | inoutbuf[2] = (data->dac_value & 0xf) << 4; |
113 | |
114 | ret = i2c_master_send(client: data->client, buf: inoutbuf, count: 3); |
115 | if (ret < 0) |
116 | return ret; |
117 | else if (ret != 3) |
118 | return -EIO; |
119 | |
120 | /* wait for write complete, takes up to 50ms */ |
121 | while (tries--) { |
122 | msleep(msecs: 20); |
123 | ret = i2c_master_recv(client: data->client, buf: inoutbuf, count: 3); |
124 | if (ret < 0) |
125 | return ret; |
126 | else if (ret != 3) |
127 | return -EIO; |
128 | |
129 | if (inoutbuf[0] & 0x80) |
130 | break; |
131 | } |
132 | |
133 | if (tries < 0) { |
134 | dev_err(&data->client->dev, |
135 | "mcp4725_store_eeprom() failed, incomplete\n" ); |
136 | return -EIO; |
137 | } |
138 | |
139 | return len; |
140 | } |
141 | |
142 | static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0); |
143 | |
144 | static struct attribute *mcp4725_attributes[] = { |
145 | &iio_dev_attr_store_eeprom.dev_attr.attr, |
146 | NULL, |
147 | }; |
148 | |
149 | static const struct attribute_group mcp4725_attribute_group = { |
150 | .attrs = mcp4725_attributes, |
151 | }; |
152 | |
153 | static const char * const mcp4725_powerdown_modes[] = { |
154 | "1kohm_to_gnd" , |
155 | "100kohm_to_gnd" , |
156 | "500kohm_to_gnd" |
157 | }; |
158 | |
159 | static const char * const mcp4726_powerdown_modes[] = { |
160 | "1kohm_to_gnd" , |
161 | "125kohm_to_gnd" , |
162 | "640kohm_to_gnd" |
163 | }; |
164 | |
165 | static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev, |
166 | const struct iio_chan_spec *chan) |
167 | { |
168 | struct mcp4725_data *data = iio_priv(indio_dev); |
169 | |
170 | return data->powerdown_mode; |
171 | } |
172 | |
173 | static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev, |
174 | const struct iio_chan_spec *chan, unsigned mode) |
175 | { |
176 | struct mcp4725_data *data = iio_priv(indio_dev); |
177 | |
178 | data->powerdown_mode = mode; |
179 | |
180 | return 0; |
181 | } |
182 | |
183 | static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev, |
184 | uintptr_t private, const struct iio_chan_spec *chan, char *buf) |
185 | { |
186 | struct mcp4725_data *data = iio_priv(indio_dev); |
187 | |
188 | return sysfs_emit(buf, fmt: "%d\n" , data->powerdown); |
189 | } |
190 | |
191 | static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev, |
192 | uintptr_t private, const struct iio_chan_spec *chan, |
193 | const char *buf, size_t len) |
194 | { |
195 | struct mcp4725_data *data = iio_priv(indio_dev); |
196 | bool state; |
197 | int ret; |
198 | |
199 | ret = kstrtobool(s: buf, res: &state); |
200 | if (ret) |
201 | return ret; |
202 | |
203 | if (state) |
204 | ret = mcp4725_suspend(dev: &data->client->dev); |
205 | else |
206 | ret = mcp4725_resume(dev: &data->client->dev); |
207 | if (ret < 0) |
208 | return ret; |
209 | |
210 | return len; |
211 | } |
212 | |
213 | enum chip_id { |
214 | MCP4725, |
215 | MCP4726, |
216 | }; |
217 | |
218 | static const struct iio_enum mcp472x_powerdown_mode_enum[] = { |
219 | [MCP4725] = { |
220 | .items = mcp4725_powerdown_modes, |
221 | .num_items = ARRAY_SIZE(mcp4725_powerdown_modes), |
222 | .get = mcp4725_get_powerdown_mode, |
223 | .set = mcp4725_set_powerdown_mode, |
224 | }, |
225 | [MCP4726] = { |
226 | .items = mcp4726_powerdown_modes, |
227 | .num_items = ARRAY_SIZE(mcp4726_powerdown_modes), |
228 | .get = mcp4725_get_powerdown_mode, |
229 | .set = mcp4725_set_powerdown_mode, |
230 | }, |
231 | }; |
232 | |
233 | static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = { |
234 | { |
235 | .name = "powerdown" , |
236 | .read = mcp4725_read_powerdown, |
237 | .write = mcp4725_write_powerdown, |
238 | .shared = IIO_SEPARATE, |
239 | }, |
240 | IIO_ENUM("powerdown_mode" , IIO_SEPARATE, |
241 | &mcp472x_powerdown_mode_enum[MCP4725]), |
242 | IIO_ENUM_AVAILABLE("powerdown_mode" , IIO_SHARED_BY_TYPE, |
243 | &mcp472x_powerdown_mode_enum[MCP4725]), |
244 | { }, |
245 | }; |
246 | |
247 | static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = { |
248 | { |
249 | .name = "powerdown" , |
250 | .read = mcp4725_read_powerdown, |
251 | .write = mcp4725_write_powerdown, |
252 | .shared = IIO_SEPARATE, |
253 | }, |
254 | IIO_ENUM("powerdown_mode" , IIO_SEPARATE, |
255 | &mcp472x_powerdown_mode_enum[MCP4726]), |
256 | IIO_ENUM_AVAILABLE("powerdown_mode" , IIO_SHARED_BY_TYPE, |
257 | &mcp472x_powerdown_mode_enum[MCP4726]), |
258 | { }, |
259 | }; |
260 | |
261 | static const struct iio_chan_spec mcp472x_channel[] = { |
262 | [MCP4725] = { |
263 | .type = IIO_VOLTAGE, |
264 | .indexed = 1, |
265 | .output = 1, |
266 | .channel = 0, |
267 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), |
268 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), |
269 | .ext_info = mcp4725_ext_info, |
270 | }, |
271 | [MCP4726] = { |
272 | .type = IIO_VOLTAGE, |
273 | .indexed = 1, |
274 | .output = 1, |
275 | .channel = 0, |
276 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), |
277 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), |
278 | .ext_info = mcp4726_ext_info, |
279 | }, |
280 | }; |
281 | |
282 | static int mcp4725_set_value(struct iio_dev *indio_dev, int val) |
283 | { |
284 | struct mcp4725_data *data = iio_priv(indio_dev); |
285 | u8 outbuf[2]; |
286 | int ret; |
287 | |
288 | if (val >= (1 << 12) || val < 0) |
289 | return -EINVAL; |
290 | |
291 | outbuf[0] = (val >> 8) & 0xf; |
292 | outbuf[1] = val & 0xff; |
293 | |
294 | ret = i2c_master_send(client: data->client, buf: outbuf, count: 2); |
295 | if (ret < 0) |
296 | return ret; |
297 | else if (ret != 2) |
298 | return -EIO; |
299 | else |
300 | return 0; |
301 | } |
302 | |
303 | static int mcp4726_set_cfg(struct iio_dev *indio_dev) |
304 | { |
305 | struct mcp4725_data *data = iio_priv(indio_dev); |
306 | u8 outbuf[3]; |
307 | int ret; |
308 | |
309 | outbuf[0] = 0x40; |
310 | outbuf[0] |= data->ref_mode << 3; |
311 | if (data->powerdown) |
312 | outbuf[0] |= data->powerdown << 1; |
313 | outbuf[1] = data->dac_value >> 4; |
314 | outbuf[2] = (data->dac_value & 0xf) << 4; |
315 | |
316 | ret = i2c_master_send(client: data->client, buf: outbuf, count: 3); |
317 | if (ret < 0) |
318 | return ret; |
319 | else if (ret != 3) |
320 | return -EIO; |
321 | else |
322 | return 0; |
323 | } |
324 | |
325 | static int mcp4725_read_raw(struct iio_dev *indio_dev, |
326 | struct iio_chan_spec const *chan, |
327 | int *val, int *val2, long mask) |
328 | { |
329 | struct mcp4725_data *data = iio_priv(indio_dev); |
330 | int ret; |
331 | |
332 | switch (mask) { |
333 | case IIO_CHAN_INFO_RAW: |
334 | *val = data->dac_value; |
335 | return IIO_VAL_INT; |
336 | case IIO_CHAN_INFO_SCALE: |
337 | if (data->ref_mode == MCP472X_REF_VDD) |
338 | ret = regulator_get_voltage(regulator: data->vdd_reg); |
339 | else |
340 | ret = regulator_get_voltage(regulator: data->vref_reg); |
341 | |
342 | if (ret < 0) |
343 | return ret; |
344 | |
345 | *val = ret / 1000; |
346 | *val2 = 12; |
347 | return IIO_VAL_FRACTIONAL_LOG2; |
348 | } |
349 | return -EINVAL; |
350 | } |
351 | |
352 | static int mcp4725_write_raw(struct iio_dev *indio_dev, |
353 | struct iio_chan_spec const *chan, |
354 | int val, int val2, long mask) |
355 | { |
356 | struct mcp4725_data *data = iio_priv(indio_dev); |
357 | int ret; |
358 | |
359 | switch (mask) { |
360 | case IIO_CHAN_INFO_RAW: |
361 | ret = mcp4725_set_value(indio_dev, val); |
362 | data->dac_value = val; |
363 | break; |
364 | default: |
365 | ret = -EINVAL; |
366 | break; |
367 | } |
368 | |
369 | return ret; |
370 | } |
371 | |
372 | static const struct iio_info mcp4725_info = { |
373 | .read_raw = mcp4725_read_raw, |
374 | .write_raw = mcp4725_write_raw, |
375 | .attrs = &mcp4725_attribute_group, |
376 | }; |
377 | |
378 | static int mcp4725_probe_dt(struct device *dev, |
379 | struct mcp4725_platform_data *pdata) |
380 | { |
381 | /* check if is the vref-supply defined */ |
382 | pdata->use_vref = device_property_read_bool(dev, propname: "vref-supply" ); |
383 | pdata->vref_buffered = |
384 | device_property_read_bool(dev, propname: "microchip,vref-buffered" ); |
385 | |
386 | return 0; |
387 | } |
388 | |
389 | static int mcp4725_probe(struct i2c_client *client) |
390 | { |
391 | const struct i2c_device_id *id = i2c_client_get_device_id(client); |
392 | const struct mcp4725_chip_info *info; |
393 | struct mcp4725_data *data; |
394 | struct iio_dev *indio_dev; |
395 | struct mcp4725_platform_data *pdata, pdata_dt; |
396 | u8 inbuf[4]; |
397 | u8 pd; |
398 | u8 ref; |
399 | int err; |
400 | |
401 | indio_dev = devm_iio_device_alloc(parent: &client->dev, sizeof_priv: sizeof(*data)); |
402 | if (indio_dev == NULL) |
403 | return -ENOMEM; |
404 | data = iio_priv(indio_dev); |
405 | i2c_set_clientdata(client, data: indio_dev); |
406 | data->client = client; |
407 | info = i2c_get_match_data(client); |
408 | pdata = dev_get_platdata(dev: &client->dev); |
409 | |
410 | if (!pdata) { |
411 | err = mcp4725_probe_dt(dev: &client->dev, pdata: &pdata_dt); |
412 | if (err) { |
413 | dev_err(&client->dev, |
414 | "invalid platform or devicetree data" ); |
415 | return err; |
416 | } |
417 | pdata = &pdata_dt; |
418 | } |
419 | |
420 | if (info->use_ext_ref_voltage && pdata->use_vref) { |
421 | dev_err(&client->dev, |
422 | "external reference is unavailable on MCP4725" ); |
423 | return -EINVAL; |
424 | } |
425 | |
426 | if (!pdata->use_vref && pdata->vref_buffered) { |
427 | dev_err(&client->dev, |
428 | "buffering is unavailable on the internal reference" ); |
429 | return -EINVAL; |
430 | } |
431 | |
432 | if (!pdata->use_vref) |
433 | data->ref_mode = MCP472X_REF_VDD; |
434 | else |
435 | data->ref_mode = pdata->vref_buffered ? |
436 | MCP472X_REF_VREF_BUFFERED : |
437 | MCP472X_REF_VREF_UNBUFFERED; |
438 | |
439 | data->vdd_reg = devm_regulator_get(dev: &client->dev, id: "vdd" ); |
440 | if (IS_ERR(ptr: data->vdd_reg)) |
441 | return PTR_ERR(ptr: data->vdd_reg); |
442 | |
443 | err = regulator_enable(regulator: data->vdd_reg); |
444 | if (err) |
445 | return err; |
446 | |
447 | if (pdata->use_vref) { |
448 | data->vref_reg = devm_regulator_get(dev: &client->dev, id: "vref" ); |
449 | if (IS_ERR(ptr: data->vref_reg)) { |
450 | err = PTR_ERR(ptr: data->vref_reg); |
451 | goto err_disable_vdd_reg; |
452 | } |
453 | |
454 | err = regulator_enable(regulator: data->vref_reg); |
455 | if (err) |
456 | goto err_disable_vdd_reg; |
457 | } |
458 | |
459 | indio_dev->name = id->name; |
460 | indio_dev->info = &mcp4725_info; |
461 | indio_dev->channels = info->chan_spec; |
462 | indio_dev->num_channels = 1; |
463 | indio_dev->modes = INDIO_DIRECT_MODE; |
464 | |
465 | /* read current DAC value and settings */ |
466 | err = i2c_master_recv(client, buf: inbuf, count: info->dac_reg_offset); |
467 | |
468 | if (err < 0) { |
469 | dev_err(&client->dev, "failed to read DAC value" ); |
470 | goto err_disable_vref_reg; |
471 | } |
472 | pd = (inbuf[0] >> 1) & 0x3; |
473 | data->powerdown = pd > 0; |
474 | data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */ |
475 | data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4); |
476 | if (!info->use_ext_ref_voltage) |
477 | ref = (inbuf[3] >> 3) & 0x3; |
478 | |
479 | if (!info->use_ext_ref_voltage && ref != data->ref_mode) { |
480 | dev_info(&client->dev, |
481 | "voltage reference mode differs (conf: %u, eeprom: %u), setting %u" , |
482 | data->ref_mode, ref, data->ref_mode); |
483 | err = mcp4726_set_cfg(indio_dev); |
484 | if (err < 0) |
485 | goto err_disable_vref_reg; |
486 | } |
487 | |
488 | err = iio_device_register(indio_dev); |
489 | if (err) |
490 | goto err_disable_vref_reg; |
491 | |
492 | return 0; |
493 | |
494 | err_disable_vref_reg: |
495 | if (data->vref_reg) |
496 | regulator_disable(regulator: data->vref_reg); |
497 | |
498 | err_disable_vdd_reg: |
499 | regulator_disable(regulator: data->vdd_reg); |
500 | |
501 | return err; |
502 | } |
503 | |
504 | static void mcp4725_remove(struct i2c_client *client) |
505 | { |
506 | struct iio_dev *indio_dev = i2c_get_clientdata(client); |
507 | struct mcp4725_data *data = iio_priv(indio_dev); |
508 | |
509 | iio_device_unregister(indio_dev); |
510 | |
511 | if (data->vref_reg) |
512 | regulator_disable(regulator: data->vref_reg); |
513 | regulator_disable(regulator: data->vdd_reg); |
514 | } |
515 | |
516 | static const struct mcp4725_chip_info mcp4725 = { |
517 | .chan_spec = &mcp472x_channel[MCP4725], |
518 | .dac_reg_offset = 3, |
519 | .use_ext_ref_voltage = true, |
520 | }; |
521 | |
522 | static const struct mcp4725_chip_info mcp4726 = { |
523 | .chan_spec = &mcp472x_channel[MCP4726], |
524 | .dac_reg_offset = 4, |
525 | }; |
526 | |
527 | static const struct i2c_device_id mcp4725_id[] = { |
528 | { "mcp4725" , (kernel_ulong_t)&mcp4725 }, |
529 | { "mcp4726" , (kernel_ulong_t)&mcp4726 }, |
530 | { } |
531 | }; |
532 | MODULE_DEVICE_TABLE(i2c, mcp4725_id); |
533 | |
534 | static const struct of_device_id mcp4725_of_match[] = { |
535 | { |
536 | .compatible = "microchip,mcp4725" , |
537 | .data = &mcp4725 |
538 | }, |
539 | { |
540 | .compatible = "microchip,mcp4726" , |
541 | .data = &mcp4726 |
542 | }, |
543 | { } |
544 | }; |
545 | MODULE_DEVICE_TABLE(of, mcp4725_of_match); |
546 | |
547 | static struct i2c_driver mcp4725_driver = { |
548 | .driver = { |
549 | .name = MCP4725_DRV_NAME, |
550 | .of_match_table = mcp4725_of_match, |
551 | .pm = pm_sleep_ptr(&mcp4725_pm_ops), |
552 | }, |
553 | .probe = mcp4725_probe, |
554 | .remove = mcp4725_remove, |
555 | .id_table = mcp4725_id, |
556 | }; |
557 | module_i2c_driver(mcp4725_driver); |
558 | |
559 | MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>" ); |
560 | MODULE_DESCRIPTION("MCP4725/6 12-bit DAC" ); |
561 | MODULE_LICENSE("GPL" ); |
562 | |