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treewide: remove redundant IS_ERR() before error code check
[linux/fpc-iii.git] / drivers / iio / adc / mcp320x.c
blob465c7625a55a4026888abdeba6c31aefdff14cea
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
4 * Copyright (C) 2014 Rose Technology
5 * Allan Bendorff Jensen <abj@rosetechnology.dk>
6 * Soren Andersen <san@rosetechnology.dk>
7 *
8 * Driver for following ADC chips from Microchip Technology's:
9 * 10 Bit converter
10 * MCP3001
11 * MCP3002
12 * MCP3004
13 * MCP3008
14 * ------------
15 * 12 bit converter
16 * MCP3201
17 * MCP3202
18 * MCP3204
19 * MCP3208
20 * ------------
21 * 13 bit converter
22 * MCP3301
23 * ------------
24 * 22 bit converter
25 * MCP3550
26 * MCP3551
27 * MCP3553
28 *
29 * Datasheet can be found here:
30 * http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf mcp3001
31 * http://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf mcp3002
32 * http://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf mcp3004/08
33 * http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf mcp3201
34 * http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf mcp3202
35 * http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf mcp3204/08
36 * http://ww1.microchip.com/downloads/en/DeviceDoc/21700E.pdf mcp3301
37 * http://ww1.microchip.com/downloads/en/DeviceDoc/21950D.pdf mcp3550/1/3
38 */
39
40 #include <linux/err.h>
41 #include <linux/delay.h>
42 #include <linux/spi/spi.h>
43 #include <linux/module.h>
44 #include <linux/iio/iio.h>
45 #include <linux/regulator/consumer.h>
46
47 enum {
48 mcp3001,
49 mcp3002,
50 mcp3004,
51 mcp3008,
52 mcp3201,
53 mcp3202,
54 mcp3204,
55 mcp3208,
56 mcp3301,
57 mcp3550_50,
58 mcp3550_60,
59 mcp3551,
60 mcp3553,
61 };
62
63 struct mcp320x_chip_info {
64 const struct iio_chan_spec *channels;
65 unsigned int num_channels;
66 unsigned int resolution;
67 unsigned int conv_time; /* usec */
68 };
69
70 /**
71 * struct mcp320x - Microchip SPI ADC instance
72 * @spi: SPI slave (parent of the IIO device)
73 * @msg: SPI message to select a channel and receive a value from the ADC
74 * @transfer: SPI transfers used by @msg
75 * @start_conv_msg: SPI message to start a conversion by briefly asserting CS
76 * @start_conv_transfer: SPI transfer used by @start_conv_msg
77 * @reg: regulator generating Vref
78 * @lock: protects read sequences
79 * @chip_info: ADC properties
80 * @tx_buf: buffer for @transfer[0] (not used on single-channel converters)
81 * @rx_buf: buffer for @transfer[1]
82 */
83 struct mcp320x {
84 struct spi_device *spi;
85 struct spi_message msg;
86 struct spi_transfer transfer[2];
87 struct spi_message start_conv_msg;
88 struct spi_transfer start_conv_transfer;
89
90 struct regulator *reg;
91 struct mutex lock;
92 const struct mcp320x_chip_info *chip_info;
93
94 u8 tx_buf ____cacheline_aligned;
95 u8 rx_buf[4];
96 };
97
98 static int mcp320x_channel_to_tx_data(int device_index,
99 const unsigned int channel, bool differential)
100 {
101 int start_bit = 1;
102
103 switch (device_index) {
104 case mcp3002:
105 case mcp3202:
106 return ((start_bit << 4) | (!differential << 3) |
107 (channel << 2));
108 case mcp3004:
109 case mcp3204:
110 case mcp3008:
111 case mcp3208:
112 return ((start_bit << 6) | (!differential << 5) |
113 (channel << 2));
114 default:
115 return -EINVAL;
116 }
117 }
118
119 static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
120 bool differential, int device_index, int *val)
121 {
122 int ret;
123
124 if (adc->chip_info->conv_time) {
125 ret = spi_sync(adc->spi, &adc->start_conv_msg);
126 if (ret < 0)
127 return ret;
128
129 usleep_range(adc->chip_info->conv_time,
130 adc->chip_info->conv_time + 100);
131 }
132
133 memset(&adc->rx_buf, 0, sizeof(adc->rx_buf));
134 if (adc->chip_info->num_channels > 1)
135 adc->tx_buf = mcp320x_channel_to_tx_data(device_index, channel,
136 differential);
137
138 ret = spi_sync(adc->spi, &adc->msg);
139 if (ret < 0)
140 return ret;
141
142 switch (device_index) {
143 case mcp3001:
144 *val = (adc->rx_buf[0] << 5 | adc->rx_buf[1] >> 3);
145 return 0;
146 case mcp3002:
147 case mcp3004:
148 case mcp3008:
149 *val = (adc->rx_buf[0] << 2 | adc->rx_buf[1] >> 6);
150 return 0;
151 case mcp3201:
152 *val = (adc->rx_buf[0] << 7 | adc->rx_buf[1] >> 1);
153 return 0;
154 case mcp3202:
155 case mcp3204:
156 case mcp3208:
157 *val = (adc->rx_buf[0] << 4 | adc->rx_buf[1] >> 4);
158 return 0;
159 case mcp3301:
160 *val = sign_extend32((adc->rx_buf[0] & 0x1f) << 8
161 | adc->rx_buf[1], 12);
162 return 0;
163 case mcp3550_50:
164 case mcp3550_60:
165 case mcp3551:
166 case mcp3553: {
167 u32 raw = be32_to_cpup((__be32 *)adc->rx_buf);
168
169 if (!(adc->spi->mode & SPI_CPOL))
170 raw <<= 1; /* strip Data Ready bit in SPI mode 0,0 */
171
172 /*
173 * If the input is within -vref and vref, bit 21 is the sign.
174 * Up to 12% overrange or underrange are allowed, in which case
175 * bit 23 is the sign and bit 0 to 21 is the value.
176 */
177 raw >>= 8;
178 if (raw & BIT(22) && raw & BIT(23))
179 return -EIO; /* cannot have overrange AND underrange */
180 else if (raw & BIT(22))
181 raw &= ~BIT(22); /* overrange */
182 else if (raw & BIT(23) || raw & BIT(21))
183 raw |= GENMASK(31, 22); /* underrange or negative */
184
185 *val = (s32)raw;
186 return 0;
187 }
188 default:
189 return -EINVAL;
190 }
191 }
192
193 static int mcp320x_read_raw(struct iio_dev *indio_dev,
194 struct iio_chan_spec const *channel, int *val,
195 int *val2, long mask)
196 {
197 struct mcp320x *adc = iio_priv(indio_dev);
198 int ret = -EINVAL;
199 int device_index = 0;
200
201 mutex_lock(&adc->lock);
202
203 device_index = spi_get_device_id(adc->spi)->driver_data;
204
205 switch (mask) {
206 case IIO_CHAN_INFO_RAW:
207 ret = mcp320x_adc_conversion(adc, channel->address,
208 channel->differential, device_index, val);
209 if (ret < 0)
210 goto out;
211
212 ret = IIO_VAL_INT;
213 break;
214
215 case IIO_CHAN_INFO_SCALE:
216 ret = regulator_get_voltage(adc->reg);
217 if (ret < 0)
218 goto out;
219
220 /* convert regulator output voltage to mV */
221 *val = ret / 1000;
222 *val2 = adc->chip_info->resolution;
223 ret = IIO_VAL_FRACTIONAL_LOG2;
224 break;
225 }
226
227 out:
228 mutex_unlock(&adc->lock);
229
230 return ret;
231 }
232
233 #define MCP320X_VOLTAGE_CHANNEL(num) \
234 { \
235 .type = IIO_VOLTAGE, \
236 .indexed = 1, \
237 .channel = (num), \
238 .address = (num), \
239 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
240 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
241 }
242
243 #define MCP320X_VOLTAGE_CHANNEL_DIFF(chan1, chan2) \
244 { \
245 .type = IIO_VOLTAGE, \
246 .indexed = 1, \
247 .channel = (chan1), \
248 .channel2 = (chan2), \
249 .address = (chan1), \
250 .differential = 1, \
251 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
252 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
253 }
254
255 static const struct iio_chan_spec mcp3201_channels[] = {
256 MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
257 };
258
259 static const struct iio_chan_spec mcp3202_channels[] = {
260 MCP320X_VOLTAGE_CHANNEL(0),
261 MCP320X_VOLTAGE_CHANNEL(1),
262 MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
263 MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
264 };
265
266 static const struct iio_chan_spec mcp3204_channels[] = {
267 MCP320X_VOLTAGE_CHANNEL(0),
268 MCP320X_VOLTAGE_CHANNEL(1),
269 MCP320X_VOLTAGE_CHANNEL(2),
270 MCP320X_VOLTAGE_CHANNEL(3),
271 MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
272 MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
273 MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
274 MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
275 };
276
277 static const struct iio_chan_spec mcp3208_channels[] = {
278 MCP320X_VOLTAGE_CHANNEL(0),
279 MCP320X_VOLTAGE_CHANNEL(1),
280 MCP320X_VOLTAGE_CHANNEL(2),
281 MCP320X_VOLTAGE_CHANNEL(3),
282 MCP320X_VOLTAGE_CHANNEL(4),
283 MCP320X_VOLTAGE_CHANNEL(5),
284 MCP320X_VOLTAGE_CHANNEL(6),
285 MCP320X_VOLTAGE_CHANNEL(7),
286 MCP320X_VOLTAGE_CHANNEL_DIFF(0, 1),
287 MCP320X_VOLTAGE_CHANNEL_DIFF(1, 0),
288 MCP320X_VOLTAGE_CHANNEL_DIFF(2, 3),
289 MCP320X_VOLTAGE_CHANNEL_DIFF(3, 2),
290 MCP320X_VOLTAGE_CHANNEL_DIFF(4, 5),
291 MCP320X_VOLTAGE_CHANNEL_DIFF(5, 4),
292 MCP320X_VOLTAGE_CHANNEL_DIFF(6, 7),
293 MCP320X_VOLTAGE_CHANNEL_DIFF(7, 6),
294 };
295
296 static const struct iio_info mcp320x_info = {
297 .read_raw = mcp320x_read_raw,
298 };
299
300 static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
301 [mcp3001] = {
302 .channels = mcp3201_channels,
303 .num_channels = ARRAY_SIZE(mcp3201_channels),
304 .resolution = 10
305 },
306 [mcp3002] = {
307 .channels = mcp3202_channels,
308 .num_channels = ARRAY_SIZE(mcp3202_channels),
309 .resolution = 10
310 },
311 [mcp3004] = {
312 .channels = mcp3204_channels,
313 .num_channels = ARRAY_SIZE(mcp3204_channels),
314 .resolution = 10
315 },
316 [mcp3008] = {
317 .channels = mcp3208_channels,
318 .num_channels = ARRAY_SIZE(mcp3208_channels),
319 .resolution = 10
320 },
321 [mcp3201] = {
322 .channels = mcp3201_channels,
323 .num_channels = ARRAY_SIZE(mcp3201_channels),
324 .resolution = 12
325 },
326 [mcp3202] = {
327 .channels = mcp3202_channels,
328 .num_channels = ARRAY_SIZE(mcp3202_channels),
329 .resolution = 12
330 },
331 [mcp3204] = {
332 .channels = mcp3204_channels,
333 .num_channels = ARRAY_SIZE(mcp3204_channels),
334 .resolution = 12
335 },
336 [mcp3208] = {
337 .channels = mcp3208_channels,
338 .num_channels = ARRAY_SIZE(mcp3208_channels),
339 .resolution = 12
340 },
341 [mcp3301] = {
342 .channels = mcp3201_channels,
343 .num_channels = ARRAY_SIZE(mcp3201_channels),
344 .resolution = 13
345 },
346 [mcp3550_50] = {
347 .channels = mcp3201_channels,
348 .num_channels = ARRAY_SIZE(mcp3201_channels),
349 .resolution = 21,
350 /* 2% max deviation + 144 clock periods to exit shutdown */
351 .conv_time = 80000 * 1.02 + 144000 / 102.4,
352 },
353 [mcp3550_60] = {
354 .channels = mcp3201_channels,
355 .num_channels = ARRAY_SIZE(mcp3201_channels),
356 .resolution = 21,
357 .conv_time = 66670 * 1.02 + 144000 / 122.88,
358 },
359 [mcp3551] = {
360 .channels = mcp3201_channels,
361 .num_channels = ARRAY_SIZE(mcp3201_channels),
362 .resolution = 21,
363 .conv_time = 73100 * 1.02 + 144000 / 112.64,
364 },
365 [mcp3553] = {
366 .channels = mcp3201_channels,
367 .num_channels = ARRAY_SIZE(mcp3201_channels),
368 .resolution = 21,
369 .conv_time = 16670 * 1.02 + 144000 / 122.88,
370 },
371 };
372
373 static int mcp320x_probe(struct spi_device *spi)
374 {
375 struct iio_dev *indio_dev;
376 struct mcp320x *adc;
377 const struct mcp320x_chip_info *chip_info;
378 int ret, device_index;
379
380 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
381 if (!indio_dev)
382 return -ENOMEM;
383
384 adc = iio_priv(indio_dev);
385 adc->spi = spi;
386
387 indio_dev->dev.parent = &spi->dev;
388 indio_dev->dev.of_node = spi->dev.of_node;
389 indio_dev->name = spi_get_device_id(spi)->name;
390 indio_dev->modes = INDIO_DIRECT_MODE;
391 indio_dev->info = &mcp320x_info;
392 spi_set_drvdata(spi, indio_dev);
393
394 device_index = spi_get_device_id(spi)->driver_data;
395 chip_info = &mcp320x_chip_infos[device_index];
396 indio_dev->channels = chip_info->channels;
397 indio_dev->num_channels = chip_info->num_channels;
398
399 adc->chip_info = chip_info;
400
401 adc->transfer[0].tx_buf = &adc->tx_buf;
402 adc->transfer[0].len = sizeof(adc->tx_buf);
403 adc->transfer[1].rx_buf = adc->rx_buf;
404 adc->transfer[1].len = DIV_ROUND_UP(chip_info->resolution, 8);
405
406 if (chip_info->num_channels == 1)
407 /* single-channel converters are rx only (no MOSI pin) */
408 spi_message_init_with_transfers(&adc->msg,
409 &adc->transfer[1], 1);
410 else
411 spi_message_init_with_transfers(&adc->msg, adc->transfer,
412 ARRAY_SIZE(adc->transfer));
413
414 switch (device_index) {
415 case mcp3550_50:
416 case mcp3550_60:
417 case mcp3551:
418 case mcp3553:
419 /* rx len increases from 24 to 25 bit in SPI mode 0,0 */
420 if (!(spi->mode & SPI_CPOL))
421 adc->transfer[1].len++;
422
423 /* conversions are started by asserting CS pin for 8 usec */
424 adc->start_conv_transfer.delay_usecs = 8;
425 spi_message_init_with_transfers(&adc->start_conv_msg,
426 &adc->start_conv_transfer, 1);
427
428 /*
429 * If CS was previously kept low (continuous conversion mode)
430 * and then changed to high, the chip is in shutdown.
431 * Sometimes it fails to wake from shutdown and clocks out
432 * only 0xffffff. The magic sequence of performing two
433 * conversions without delay between them resets the chip
434 * and ensures all subsequent conversions succeed.
435 */
436 mcp320x_adc_conversion(adc, 0, 1, device_index, &ret);
437 mcp320x_adc_conversion(adc, 0, 1, device_index, &ret);
438 }
439
440 adc->reg = devm_regulator_get(&spi->dev, "vref");
441 if (IS_ERR(adc->reg))
442 return PTR_ERR(adc->reg);
443
444 ret = regulator_enable(adc->reg);
445 if (ret < 0)
446 return ret;
447
448 mutex_init(&adc->lock);
449
450 ret = iio_device_register(indio_dev);
451 if (ret < 0)
452 goto reg_disable;
453
454 return 0;
455
456 reg_disable:
457 regulator_disable(adc->reg);
458
459 return ret;
460 }
461
462 static int mcp320x_remove(struct spi_device *spi)
463 {
464 struct iio_dev *indio_dev = spi_get_drvdata(spi);
465 struct mcp320x *adc = iio_priv(indio_dev);
466
467 iio_device_unregister(indio_dev);
468 regulator_disable(adc->reg);
469
470 return 0;
471 }
472
473 #if defined(CONFIG_OF)
474 static const struct of_device_id mcp320x_dt_ids[] = {
475 /* NOTE: The use of compatibles with no vendor prefix is deprecated. */
476 { .compatible = "mcp3001" },
477 { .compatible = "mcp3002" },
478 { .compatible = "mcp3004" },
479 { .compatible = "mcp3008" },
480 { .compatible = "mcp3201" },
481 { .compatible = "mcp3202" },
482 { .compatible = "mcp3204" },
483 { .compatible = "mcp3208" },
484 { .compatible = "mcp3301" },
485 { .compatible = "microchip,mcp3001" },
486 { .compatible = "microchip,mcp3002" },
487 { .compatible = "microchip,mcp3004" },
488 { .compatible = "microchip,mcp3008" },
489 { .compatible = "microchip,mcp3201" },
490 { .compatible = "microchip,mcp3202" },
491 { .compatible = "microchip,mcp3204" },
492 { .compatible = "microchip,mcp3208" },
493 { .compatible = "microchip,mcp3301" },
494 { .compatible = "microchip,mcp3550-50" },
495 { .compatible = "microchip,mcp3550-60" },
496 { .compatible = "microchip,mcp3551" },
497 { .compatible = "microchip,mcp3553" },
498 { }
499 };
500 MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
501 #endif
502
503 static const struct spi_device_id mcp320x_id[] = {
504 { "mcp3001", mcp3001 },
505 { "mcp3002", mcp3002 },
506 { "mcp3004", mcp3004 },
507 { "mcp3008", mcp3008 },
508 { "mcp3201", mcp3201 },
509 { "mcp3202", mcp3202 },
510 { "mcp3204", mcp3204 },
511 { "mcp3208", mcp3208 },
512 { "mcp3301", mcp3301 },
513 { "mcp3550-50", mcp3550_50 },
514 { "mcp3550-60", mcp3550_60 },
515 { "mcp3551", mcp3551 },
516 { "mcp3553", mcp3553 },
517 { }
518 };
519 MODULE_DEVICE_TABLE(spi, mcp320x_id);
520
521 static struct spi_driver mcp320x_driver = {
522 .driver = {
523 .name = "mcp320x",
524 .of_match_table = of_match_ptr(mcp320x_dt_ids),
525 },
526 .probe = mcp320x_probe,
527 .remove = mcp320x_remove,
528 .id_table = mcp320x_id,
529 };
530 module_spi_driver(mcp320x_driver);
531
532 MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
533 MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08 and MCP3550/1/3");
534 MODULE_LICENSE("GPL v2");
Linux with added FPC-III support