xref: /openbmc/linux/drivers/iio/adc/sc27xx_adc.c (revision d0e22329)
1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (C) 2018 Spreadtrum Communications Inc.
3 
4 #include <linux/hwspinlock.h>
5 #include <linux/iio/iio.h>
6 #include <linux/interrupt.h>
7 #include <linux/module.h>
8 #include <linux/nvmem-consumer.h>
9 #include <linux/of.h>
10 #include <linux/of_device.h>
11 #include <linux/platform_device.h>
12 #include <linux/regmap.h>
13 #include <linux/slab.h>
14 
15 /* PMIC global registers definition */
16 #define SC27XX_MODULE_EN		0xc08
17 #define SC27XX_MODULE_ADC_EN		BIT(5)
18 #define SC27XX_ARM_CLK_EN		0xc10
19 #define SC27XX_CLK_ADC_EN		BIT(5)
20 #define SC27XX_CLK_ADC_CLK_EN		BIT(6)
21 
22 /* ADC controller registers definition */
23 #define SC27XX_ADC_CTL			0x0
24 #define SC27XX_ADC_CH_CFG		0x4
25 #define SC27XX_ADC_DATA			0x4c
26 #define SC27XX_ADC_INT_EN		0x50
27 #define SC27XX_ADC_INT_CLR		0x54
28 #define SC27XX_ADC_INT_STS		0x58
29 #define SC27XX_ADC_INT_RAW		0x5c
30 
31 /* Bits and mask definition for SC27XX_ADC_CTL register */
32 #define SC27XX_ADC_EN			BIT(0)
33 #define SC27XX_ADC_CHN_RUN		BIT(1)
34 #define SC27XX_ADC_12BIT_MODE		BIT(2)
35 #define SC27XX_ADC_RUN_NUM_MASK		GENMASK(7, 4)
36 #define SC27XX_ADC_RUN_NUM_SHIFT	4
37 
38 /* Bits and mask definition for SC27XX_ADC_CH_CFG register */
39 #define SC27XX_ADC_CHN_ID_MASK		GENMASK(4, 0)
40 #define SC27XX_ADC_SCALE_MASK		GENMASK(10, 8)
41 #define SC27XX_ADC_SCALE_SHIFT		8
42 
43 /* Bits definitions for SC27XX_ADC_INT_EN registers */
44 #define SC27XX_ADC_IRQ_EN		BIT(0)
45 
46 /* Bits definitions for SC27XX_ADC_INT_CLR registers */
47 #define SC27XX_ADC_IRQ_CLR		BIT(0)
48 
49 /* Mask definition for SC27XX_ADC_DATA register */
50 #define SC27XX_ADC_DATA_MASK		GENMASK(11, 0)
51 
52 /* Timeout (ms) for the trylock of hardware spinlocks */
53 #define SC27XX_ADC_HWLOCK_TIMEOUT	5000
54 
55 /* Timeout (ms) for ADC data conversion according to ADC datasheet */
56 #define SC27XX_ADC_RDY_TIMEOUT		100
57 
58 /* Maximum ADC channel number */
59 #define SC27XX_ADC_CHANNEL_MAX		32
60 
61 /* ADC voltage ratio definition */
62 #define SC27XX_VOLT_RATIO(n, d)		\
63 	(((n) << SC27XX_RATIO_NUMERATOR_OFFSET) | (d))
64 #define SC27XX_RATIO_NUMERATOR_OFFSET	16
65 #define SC27XX_RATIO_DENOMINATOR_MASK	GENMASK(15, 0)
66 
67 struct sc27xx_adc_data {
68 	struct device *dev;
69 	struct regmap *regmap;
70 	/*
71 	 * One hardware spinlock to synchronize between the multiple
72 	 * subsystems which will access the unique ADC controller.
73 	 */
74 	struct hwspinlock *hwlock;
75 	struct completion completion;
76 	int channel_scale[SC27XX_ADC_CHANNEL_MAX];
77 	u32 base;
78 	int value;
79 	int irq;
80 };
81 
82 struct sc27xx_adc_linear_graph {
83 	int volt0;
84 	int adc0;
85 	int volt1;
86 	int adc1;
87 };
88 
89 /*
90  * According to the datasheet, we can convert one ADC value to one voltage value
91  * through 2 points in the linear graph. If the voltage is less than 1.2v, we
92  * should use the small-scale graph, and if more than 1.2v, we should use the
93  * big-scale graph.
94  */
95 static struct sc27xx_adc_linear_graph big_scale_graph = {
96 	4200, 3310,
97 	3600, 2832,
98 };
99 
100 static struct sc27xx_adc_linear_graph small_scale_graph = {
101 	1000, 3413,
102 	100, 341,
103 };
104 
105 static const struct sc27xx_adc_linear_graph big_scale_graph_calib = {
106 	4200, 856,
107 	3600, 733,
108 };
109 
110 static const struct sc27xx_adc_linear_graph small_scale_graph_calib = {
111 	1000, 833,
112 	100, 80,
113 };
114 
115 static int sc27xx_adc_get_calib_data(u32 calib_data, int calib_adc)
116 {
117 	return ((calib_data & 0xff) + calib_adc - 128) * 4;
118 }
119 
120 static int sc27xx_adc_scale_calibration(struct sc27xx_adc_data *data,
121 					bool big_scale)
122 {
123 	const struct sc27xx_adc_linear_graph *calib_graph;
124 	struct sc27xx_adc_linear_graph *graph;
125 	struct nvmem_cell *cell;
126 	const char *cell_name;
127 	u32 calib_data = 0;
128 	void *buf;
129 	size_t len;
130 
131 	if (big_scale) {
132 		calib_graph = &big_scale_graph_calib;
133 		graph = &big_scale_graph;
134 		cell_name = "big_scale_calib";
135 	} else {
136 		calib_graph = &small_scale_graph_calib;
137 		graph = &small_scale_graph;
138 		cell_name = "small_scale_calib";
139 	}
140 
141 	cell = nvmem_cell_get(data->dev, cell_name);
142 	if (IS_ERR(cell))
143 		return PTR_ERR(cell);
144 
145 	buf = nvmem_cell_read(cell, &len);
146 	nvmem_cell_put(cell);
147 
148 	if (IS_ERR(buf))
149 		return PTR_ERR(buf);
150 
151 	memcpy(&calib_data, buf, min(len, sizeof(u32)));
152 
153 	/* Only need to calibrate the adc values in the linear graph. */
154 	graph->adc0 = sc27xx_adc_get_calib_data(calib_data, calib_graph->adc0);
155 	graph->adc1 = sc27xx_adc_get_calib_data(calib_data >> 8,
156 						calib_graph->adc1);
157 
158 	kfree(buf);
159 	return 0;
160 }
161 
162 static int sc27xx_adc_get_ratio(int channel, int scale)
163 {
164 	switch (channel) {
165 	case 1:
166 	case 2:
167 	case 3:
168 	case 4:
169 		return scale ? SC27XX_VOLT_RATIO(400, 1025) :
170 			SC27XX_VOLT_RATIO(1, 1);
171 	case 5:
172 		return SC27XX_VOLT_RATIO(7, 29);
173 	case 6:
174 		return SC27XX_VOLT_RATIO(375, 9000);
175 	case 7:
176 	case 8:
177 		return scale ? SC27XX_VOLT_RATIO(100, 125) :
178 			SC27XX_VOLT_RATIO(1, 1);
179 	case 19:
180 		return SC27XX_VOLT_RATIO(1, 3);
181 	default:
182 		return SC27XX_VOLT_RATIO(1, 1);
183 	}
184 	return SC27XX_VOLT_RATIO(1, 1);
185 }
186 
187 static int sc27xx_adc_read(struct sc27xx_adc_data *data, int channel,
188 			   int scale, int *val)
189 {
190 	int ret;
191 	u32 tmp;
192 
193 	reinit_completion(&data->completion);
194 
195 	ret = hwspin_lock_timeout_raw(data->hwlock, SC27XX_ADC_HWLOCK_TIMEOUT);
196 	if (ret) {
197 		dev_err(data->dev, "timeout to get the hwspinlock\n");
198 		return ret;
199 	}
200 
201 	ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
202 				 SC27XX_ADC_EN, SC27XX_ADC_EN);
203 	if (ret)
204 		goto unlock_adc;
205 
206 	/* Configure the channel id and scale */
207 	tmp = (scale << SC27XX_ADC_SCALE_SHIFT) & SC27XX_ADC_SCALE_MASK;
208 	tmp |= channel & SC27XX_ADC_CHN_ID_MASK;
209 	ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CH_CFG,
210 				 SC27XX_ADC_CHN_ID_MASK | SC27XX_ADC_SCALE_MASK,
211 				 tmp);
212 	if (ret)
213 		goto disable_adc;
214 
215 	/* Select 12bit conversion mode, and only sample 1 time */
216 	tmp = SC27XX_ADC_12BIT_MODE;
217 	tmp |= (0 << SC27XX_ADC_RUN_NUM_SHIFT) & SC27XX_ADC_RUN_NUM_MASK;
218 	ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
219 				 SC27XX_ADC_RUN_NUM_MASK | SC27XX_ADC_12BIT_MODE,
220 				 tmp);
221 	if (ret)
222 		goto disable_adc;
223 
224 	ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
225 				 SC27XX_ADC_CHN_RUN, SC27XX_ADC_CHN_RUN);
226 	if (ret)
227 		goto disable_adc;
228 
229 	ret = wait_for_completion_timeout(&data->completion,
230 				msecs_to_jiffies(SC27XX_ADC_RDY_TIMEOUT));
231 	if (!ret) {
232 		dev_err(data->dev, "read ADC data timeout\n");
233 		ret = -ETIMEDOUT;
234 	} else {
235 		ret = 0;
236 	}
237 
238 disable_adc:
239 	regmap_update_bits(data->regmap, data->base + SC27XX_ADC_CTL,
240 			   SC27XX_ADC_EN, 0);
241 unlock_adc:
242 	hwspin_unlock_raw(data->hwlock);
243 
244 	if (!ret)
245 		*val = data->value;
246 
247 	return ret;
248 }
249 
250 static irqreturn_t sc27xx_adc_isr(int irq, void *dev_id)
251 {
252 	struct sc27xx_adc_data *data = dev_id;
253 	int ret;
254 
255 	ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_CLR,
256 				 SC27XX_ADC_IRQ_CLR, SC27XX_ADC_IRQ_CLR);
257 	if (ret)
258 		return IRQ_RETVAL(ret);
259 
260 	ret = regmap_read(data->regmap, data->base + SC27XX_ADC_DATA,
261 			  &data->value);
262 	if (ret)
263 		return IRQ_RETVAL(ret);
264 
265 	data->value &= SC27XX_ADC_DATA_MASK;
266 	complete(&data->completion);
267 
268 	return IRQ_HANDLED;
269 }
270 
271 static void sc27xx_adc_volt_ratio(struct sc27xx_adc_data *data,
272 				  int channel, int scale,
273 				  u32 *div_numerator, u32 *div_denominator)
274 {
275 	u32 ratio = sc27xx_adc_get_ratio(channel, scale);
276 
277 	*div_numerator = ratio >> SC27XX_RATIO_NUMERATOR_OFFSET;
278 	*div_denominator = ratio & SC27XX_RATIO_DENOMINATOR_MASK;
279 }
280 
281 static int sc27xx_adc_to_volt(struct sc27xx_adc_linear_graph *graph,
282 			      int raw_adc)
283 {
284 	int tmp;
285 
286 	tmp = (graph->volt0 - graph->volt1) * (raw_adc - graph->adc1);
287 	tmp /= (graph->adc0 - graph->adc1);
288 	tmp += graph->volt1;
289 
290 	return tmp < 0 ? 0 : tmp;
291 }
292 
293 static int sc27xx_adc_convert_volt(struct sc27xx_adc_data *data, int channel,
294 				   int scale, int raw_adc)
295 {
296 	u32 numerator, denominator;
297 	u32 volt;
298 
299 	/*
300 	 * Convert ADC values to voltage values according to the linear graph,
301 	 * and channel 5 and channel 1 has been calibrated, so we can just
302 	 * return the voltage values calculated by the linear graph. But other
303 	 * channels need be calculated to the real voltage values with the
304 	 * voltage ratio.
305 	 */
306 	switch (channel) {
307 	case 5:
308 		return sc27xx_adc_to_volt(&big_scale_graph, raw_adc);
309 
310 	case 1:
311 		return sc27xx_adc_to_volt(&small_scale_graph, raw_adc);
312 
313 	default:
314 		volt = sc27xx_adc_to_volt(&small_scale_graph, raw_adc);
315 		break;
316 	}
317 
318 	sc27xx_adc_volt_ratio(data, channel, scale, &numerator, &denominator);
319 
320 	return (volt * denominator + numerator / 2) / numerator;
321 }
322 
323 static int sc27xx_adc_read_processed(struct sc27xx_adc_data *data,
324 				     int channel, int scale, int *val)
325 {
326 	int ret, raw_adc;
327 
328 	ret = sc27xx_adc_read(data, channel, scale, &raw_adc);
329 	if (ret)
330 		return ret;
331 
332 	*val = sc27xx_adc_convert_volt(data, channel, scale, raw_adc);
333 	return 0;
334 }
335 
336 static int sc27xx_adc_read_raw(struct iio_dev *indio_dev,
337 			       struct iio_chan_spec const *chan,
338 			       int *val, int *val2, long mask)
339 {
340 	struct sc27xx_adc_data *data = iio_priv(indio_dev);
341 	int scale = data->channel_scale[chan->channel];
342 	int ret, tmp;
343 
344 	switch (mask) {
345 	case IIO_CHAN_INFO_RAW:
346 		mutex_lock(&indio_dev->mlock);
347 		ret = sc27xx_adc_read(data, chan->channel, scale, &tmp);
348 		mutex_unlock(&indio_dev->mlock);
349 
350 		if (ret)
351 			return ret;
352 
353 		*val = tmp;
354 		return IIO_VAL_INT;
355 
356 	case IIO_CHAN_INFO_PROCESSED:
357 		mutex_lock(&indio_dev->mlock);
358 		ret = sc27xx_adc_read_processed(data, chan->channel, scale,
359 						&tmp);
360 		mutex_unlock(&indio_dev->mlock);
361 
362 		if (ret)
363 			return ret;
364 
365 		*val = tmp;
366 		return IIO_VAL_INT;
367 
368 	case IIO_CHAN_INFO_SCALE:
369 		*val = scale;
370 		return IIO_VAL_INT;
371 
372 	default:
373 		return -EINVAL;
374 	}
375 }
376 
377 static int sc27xx_adc_write_raw(struct iio_dev *indio_dev,
378 				struct iio_chan_spec const *chan,
379 				int val, int val2, long mask)
380 {
381 	struct sc27xx_adc_data *data = iio_priv(indio_dev);
382 
383 	switch (mask) {
384 	case IIO_CHAN_INFO_SCALE:
385 		data->channel_scale[chan->channel] = val;
386 		return IIO_VAL_INT;
387 
388 	default:
389 		return -EINVAL;
390 	}
391 }
392 
393 static const struct iio_info sc27xx_info = {
394 	.read_raw = &sc27xx_adc_read_raw,
395 	.write_raw = &sc27xx_adc_write_raw,
396 };
397 
398 #define SC27XX_ADC_CHANNEL(index, mask) {			\
399 	.type = IIO_VOLTAGE,					\
400 	.channel = index,					\
401 	.info_mask_separate = mask | BIT(IIO_CHAN_INFO_SCALE),	\
402 	.datasheet_name = "CH##index",				\
403 	.indexed = 1,						\
404 }
405 
406 static const struct iio_chan_spec sc27xx_channels[] = {
407 	SC27XX_ADC_CHANNEL(0, BIT(IIO_CHAN_INFO_PROCESSED)),
408 	SC27XX_ADC_CHANNEL(1, BIT(IIO_CHAN_INFO_PROCESSED)),
409 	SC27XX_ADC_CHANNEL(2, BIT(IIO_CHAN_INFO_PROCESSED)),
410 	SC27XX_ADC_CHANNEL(3, BIT(IIO_CHAN_INFO_PROCESSED)),
411 	SC27XX_ADC_CHANNEL(4, BIT(IIO_CHAN_INFO_PROCESSED)),
412 	SC27XX_ADC_CHANNEL(5, BIT(IIO_CHAN_INFO_PROCESSED)),
413 	SC27XX_ADC_CHANNEL(6, BIT(IIO_CHAN_INFO_PROCESSED)),
414 	SC27XX_ADC_CHANNEL(7, BIT(IIO_CHAN_INFO_PROCESSED)),
415 	SC27XX_ADC_CHANNEL(8, BIT(IIO_CHAN_INFO_PROCESSED)),
416 	SC27XX_ADC_CHANNEL(9, BIT(IIO_CHAN_INFO_PROCESSED)),
417 	SC27XX_ADC_CHANNEL(10, BIT(IIO_CHAN_INFO_PROCESSED)),
418 	SC27XX_ADC_CHANNEL(11, BIT(IIO_CHAN_INFO_PROCESSED)),
419 	SC27XX_ADC_CHANNEL(12, BIT(IIO_CHAN_INFO_PROCESSED)),
420 	SC27XX_ADC_CHANNEL(13, BIT(IIO_CHAN_INFO_PROCESSED)),
421 	SC27XX_ADC_CHANNEL(14, BIT(IIO_CHAN_INFO_PROCESSED)),
422 	SC27XX_ADC_CHANNEL(15, BIT(IIO_CHAN_INFO_PROCESSED)),
423 	SC27XX_ADC_CHANNEL(16, BIT(IIO_CHAN_INFO_PROCESSED)),
424 	SC27XX_ADC_CHANNEL(17, BIT(IIO_CHAN_INFO_PROCESSED)),
425 	SC27XX_ADC_CHANNEL(18, BIT(IIO_CHAN_INFO_PROCESSED)),
426 	SC27XX_ADC_CHANNEL(19, BIT(IIO_CHAN_INFO_PROCESSED)),
427 	SC27XX_ADC_CHANNEL(20, BIT(IIO_CHAN_INFO_RAW)),
428 	SC27XX_ADC_CHANNEL(21, BIT(IIO_CHAN_INFO_PROCESSED)),
429 	SC27XX_ADC_CHANNEL(22, BIT(IIO_CHAN_INFO_PROCESSED)),
430 	SC27XX_ADC_CHANNEL(23, BIT(IIO_CHAN_INFO_PROCESSED)),
431 	SC27XX_ADC_CHANNEL(24, BIT(IIO_CHAN_INFO_PROCESSED)),
432 	SC27XX_ADC_CHANNEL(25, BIT(IIO_CHAN_INFO_PROCESSED)),
433 	SC27XX_ADC_CHANNEL(26, BIT(IIO_CHAN_INFO_PROCESSED)),
434 	SC27XX_ADC_CHANNEL(27, BIT(IIO_CHAN_INFO_PROCESSED)),
435 	SC27XX_ADC_CHANNEL(28, BIT(IIO_CHAN_INFO_PROCESSED)),
436 	SC27XX_ADC_CHANNEL(29, BIT(IIO_CHAN_INFO_PROCESSED)),
437 	SC27XX_ADC_CHANNEL(30, BIT(IIO_CHAN_INFO_PROCESSED)),
438 	SC27XX_ADC_CHANNEL(31, BIT(IIO_CHAN_INFO_PROCESSED)),
439 };
440 
441 static int sc27xx_adc_enable(struct sc27xx_adc_data *data)
442 {
443 	int ret;
444 
445 	ret = regmap_update_bits(data->regmap, SC27XX_MODULE_EN,
446 				 SC27XX_MODULE_ADC_EN, SC27XX_MODULE_ADC_EN);
447 	if (ret)
448 		return ret;
449 
450 	/* Enable ADC work clock and controller clock */
451 	ret = regmap_update_bits(data->regmap, SC27XX_ARM_CLK_EN,
452 				 SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN,
453 				 SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN);
454 	if (ret)
455 		goto disable_adc;
456 
457 	ret = regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_EN,
458 				 SC27XX_ADC_IRQ_EN, SC27XX_ADC_IRQ_EN);
459 	if (ret)
460 		goto disable_clk;
461 
462 	/* ADC channel scales' calibration from nvmem device */
463 	ret = sc27xx_adc_scale_calibration(data, true);
464 	if (ret)
465 		goto disable_clk;
466 
467 	ret = sc27xx_adc_scale_calibration(data, false);
468 	if (ret)
469 		goto disable_clk;
470 
471 	return 0;
472 
473 disable_clk:
474 	regmap_update_bits(data->regmap, SC27XX_ARM_CLK_EN,
475 			   SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN, 0);
476 disable_adc:
477 	regmap_update_bits(data->regmap, SC27XX_MODULE_EN,
478 			   SC27XX_MODULE_ADC_EN, 0);
479 
480 	return ret;
481 }
482 
483 static void sc27xx_adc_disable(void *_data)
484 {
485 	struct sc27xx_adc_data *data = _data;
486 
487 	regmap_update_bits(data->regmap, data->base + SC27XX_ADC_INT_EN,
488 			   SC27XX_ADC_IRQ_EN, 0);
489 
490 	/* Disable ADC work clock and controller clock */
491 	regmap_update_bits(data->regmap, SC27XX_ARM_CLK_EN,
492 			   SC27XX_CLK_ADC_EN | SC27XX_CLK_ADC_CLK_EN, 0);
493 
494 	regmap_update_bits(data->regmap, SC27XX_MODULE_EN,
495 			   SC27XX_MODULE_ADC_EN, 0);
496 }
497 
498 static void sc27xx_adc_free_hwlock(void *_data)
499 {
500 	struct hwspinlock *hwlock = _data;
501 
502 	hwspin_lock_free(hwlock);
503 }
504 
505 static int sc27xx_adc_probe(struct platform_device *pdev)
506 {
507 	struct device_node *np = pdev->dev.of_node;
508 	struct sc27xx_adc_data *sc27xx_data;
509 	struct iio_dev *indio_dev;
510 	int ret;
511 
512 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*sc27xx_data));
513 	if (!indio_dev)
514 		return -ENOMEM;
515 
516 	sc27xx_data = iio_priv(indio_dev);
517 
518 	sc27xx_data->regmap = dev_get_regmap(pdev->dev.parent, NULL);
519 	if (!sc27xx_data->regmap) {
520 		dev_err(&pdev->dev, "failed to get ADC regmap\n");
521 		return -ENODEV;
522 	}
523 
524 	ret = of_property_read_u32(np, "reg", &sc27xx_data->base);
525 	if (ret) {
526 		dev_err(&pdev->dev, "failed to get ADC base address\n");
527 		return ret;
528 	}
529 
530 	sc27xx_data->irq = platform_get_irq(pdev, 0);
531 	if (sc27xx_data->irq < 0) {
532 		dev_err(&pdev->dev, "failed to get ADC irq number\n");
533 		return sc27xx_data->irq;
534 	}
535 
536 	ret = of_hwspin_lock_get_id(np, 0);
537 	if (ret < 0) {
538 		dev_err(&pdev->dev, "failed to get hwspinlock id\n");
539 		return ret;
540 	}
541 
542 	sc27xx_data->hwlock = hwspin_lock_request_specific(ret);
543 	if (!sc27xx_data->hwlock) {
544 		dev_err(&pdev->dev, "failed to request hwspinlock\n");
545 		return -ENXIO;
546 	}
547 
548 	ret = devm_add_action(&pdev->dev, sc27xx_adc_free_hwlock,
549 			      sc27xx_data->hwlock);
550 	if (ret) {
551 		sc27xx_adc_free_hwlock(sc27xx_data->hwlock);
552 		dev_err(&pdev->dev, "failed to add hwspinlock action\n");
553 		return ret;
554 	}
555 
556 	init_completion(&sc27xx_data->completion);
557 	sc27xx_data->dev = &pdev->dev;
558 
559 	ret = sc27xx_adc_enable(sc27xx_data);
560 	if (ret) {
561 		dev_err(&pdev->dev, "failed to enable ADC module\n");
562 		return ret;
563 	}
564 
565 	ret = devm_add_action(&pdev->dev, sc27xx_adc_disable, sc27xx_data);
566 	if (ret) {
567 		sc27xx_adc_disable(sc27xx_data);
568 		dev_err(&pdev->dev, "failed to add ADC disable action\n");
569 		return ret;
570 	}
571 
572 	ret = devm_request_threaded_irq(&pdev->dev, sc27xx_data->irq, NULL,
573 					sc27xx_adc_isr, IRQF_ONESHOT,
574 					pdev->name, sc27xx_data);
575 	if (ret) {
576 		dev_err(&pdev->dev, "failed to request ADC irq\n");
577 		return ret;
578 	}
579 
580 	indio_dev->dev.parent = &pdev->dev;
581 	indio_dev->name = dev_name(&pdev->dev);
582 	indio_dev->modes = INDIO_DIRECT_MODE;
583 	indio_dev->info = &sc27xx_info;
584 	indio_dev->channels = sc27xx_channels;
585 	indio_dev->num_channels = ARRAY_SIZE(sc27xx_channels);
586 	ret = devm_iio_device_register(&pdev->dev, indio_dev);
587 	if (ret)
588 		dev_err(&pdev->dev, "could not register iio (ADC)");
589 
590 	return ret;
591 }
592 
593 static const struct of_device_id sc27xx_adc_of_match[] = {
594 	{ .compatible = "sprd,sc2731-adc", },
595 	{ }
596 };
597 
598 static struct platform_driver sc27xx_adc_driver = {
599 	.probe = sc27xx_adc_probe,
600 	.driver = {
601 		.name = "sc27xx-adc",
602 		.of_match_table = sc27xx_adc_of_match,
603 	},
604 };
605 
606 module_platform_driver(sc27xx_adc_driver);
607 
608 MODULE_AUTHOR("Freeman Liu <freeman.liu@spreadtrum.com>");
609 MODULE_DESCRIPTION("Spreadtrum SC27XX ADC Driver");
610 MODULE_LICENSE("GPL v2");
611