xref: /linux/drivers/iio/adc/ti_am335x_adc.c (revision a2a4ee550704901aa148b57a55cb73cc1e8ae9b1)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * TI ADC MFD driver
4  *
5  * Copyright (C) 2012 Texas Instruments Incorporated - https://www.ti.com/
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/err.h>
10 #include <linux/module.h>
11 #include <linux/slab.h>
12 #include <linux/interrupt.h>
13 #include <linux/platform_device.h>
14 #include <linux/io.h>
15 #include <linux/iio/iio.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/iio/machine.h>
19 #include <linux/iio/driver.h>
20 #include <linux/iopoll.h>
21 
22 #include <linux/mfd/ti_am335x_tscadc.h>
23 #include <linux/iio/buffer.h>
24 #include <linux/iio/kfifo_buf.h>
25 
26 #include <linux/dmaengine.h>
27 #include <linux/dma-mapping.h>
28 
29 #define DMA_BUFFER_SIZE		SZ_2K
30 
31 struct tiadc_dma {
32 	struct dma_slave_config	conf;
33 	struct dma_chan		*chan;
34 	dma_addr_t		addr;
35 	dma_cookie_t		cookie;
36 	u8			*buf;
37 	int			current_period;
38 	int			period_size;
39 	u8			fifo_thresh;
40 };
41 
42 struct tiadc_device {
43 	struct ti_tscadc_dev *mfd_tscadc;
44 	struct tiadc_dma dma;
45 	struct mutex fifo1_lock; /* to protect fifo access */
46 	int channels;
47 	int total_ch_enabled;
48 	u8 channel_line[8];
49 	u8 channel_step[8];
50 	int buffer_en_ch_steps;
51 	u16 data[8];
52 	u32 open_delay[8], sample_delay[8], step_avg[8];
53 };
54 
55 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
56 {
57 	return readl(adc->mfd_tscadc->tscadc_base + reg);
58 }
59 
60 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
61 			 unsigned int val)
62 {
63 	writel(val, adc->mfd_tscadc->tscadc_base + reg);
64 }
65 
66 static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
67 {
68 	u32 step_en;
69 
70 	step_en = ((1 << adc_dev->channels) - 1);
71 	step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
72 	return step_en;
73 }
74 
75 static u32 get_adc_chan_step_mask(struct tiadc_device *adc_dev,
76 				  struct iio_chan_spec const *chan)
77 {
78 	int i;
79 
80 	for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
81 		if (chan->channel == adc_dev->channel_line[i]) {
82 			u32 step;
83 
84 			step = adc_dev->channel_step[i];
85 			/* +1 for the charger */
86 			return 1 << (step + 1);
87 		}
88 	}
89 	WARN_ON(1);
90 	return 0;
91 }
92 
93 static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
94 {
95 	return 1 << adc_dev->channel_step[chan];
96 }
97 
98 static int tiadc_wait_idle(struct tiadc_device *adc_dev)
99 {
100 	u32 val;
101 
102 	return readl_poll_timeout(adc_dev->mfd_tscadc->tscadc_base + REG_ADCFSM,
103 				  val, !(val & SEQ_STATUS), 10,
104 				  IDLE_TIMEOUT_MS * 1000 * adc_dev->channels);
105 }
106 
107 static void tiadc_step_config(struct iio_dev *indio_dev)
108 {
109 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
110 	unsigned int stepconfig;
111 	int i, steps = 0;
112 
113 	/*
114 	 * There are 16 configurable steps and 8 analog input
115 	 * lines available which are shared between Touchscreen and ADC.
116 	 *
117 	 * Steps forwards i.e. from 0 towards 16 are used by ADC
118 	 * depending on number of input lines needed.
119 	 * Channel would represent which analog input
120 	 * needs to be given to ADC to digitalize data.
121 	 */
122 	for (i = 0; i < adc_dev->channels; i++) {
123 		int chan;
124 
125 		chan = adc_dev->channel_line[i];
126 
127 		if (adc_dev->step_avg[i])
128 			stepconfig = STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) |
129 				     STEPCONFIG_FIFO1;
130 		else
131 			stepconfig = STEPCONFIG_FIFO1;
132 
133 		if (iio_buffer_enabled(indio_dev))
134 			stepconfig |= STEPCONFIG_MODE_SWCNT;
135 
136 		tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
137 			     stepconfig | STEPCONFIG_INP(chan) |
138 			     STEPCONFIG_INM_ADCREFM | STEPCONFIG_RFP_VREFP |
139 			     STEPCONFIG_RFM_VREFN);
140 
141 		tiadc_writel(adc_dev, REG_STEPDELAY(steps),
142 			     STEPDELAY_OPEN(adc_dev->open_delay[i]) |
143 			     STEPDELAY_SAMPLE(adc_dev->sample_delay[i]));
144 
145 		adc_dev->channel_step[i] = steps;
146 		steps++;
147 	}
148 }
149 
150 static irqreturn_t tiadc_irq_h(int irq, void *private)
151 {
152 	struct iio_dev *indio_dev = private;
153 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
154 	unsigned int status, config, adc_fsm;
155 	unsigned short count = 0;
156 
157 	status = tiadc_readl(adc_dev, REG_IRQSTATUS);
158 
159 	/*
160 	 * ADC and touchscreen share the IRQ line.
161 	 * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
162 	 */
163 	if (status & IRQENB_FIFO1OVRRUN) {
164 		/* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
165 		config = tiadc_readl(adc_dev, REG_CTRL);
166 		config &= ~(CNTRLREG_SSENB);
167 		tiadc_writel(adc_dev, REG_CTRL, config);
168 		tiadc_writel(adc_dev, REG_IRQSTATUS,
169 			     IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW |
170 			     IRQENB_FIFO1THRES);
171 
172 		/*
173 		 * Wait for the idle state.
174 		 * ADC needs to finish the current conversion
175 		 * before disabling the module
176 		 */
177 		do {
178 			adc_fsm = tiadc_readl(adc_dev, REG_ADCFSM);
179 		} while (adc_fsm != 0x10 && count++ < 100);
180 
181 		tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_SSENB));
182 		return IRQ_HANDLED;
183 	} else if (status & IRQENB_FIFO1THRES) {
184 		/* Disable irq and wake worker thread */
185 		tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
186 		return IRQ_WAKE_THREAD;
187 	}
188 
189 	return IRQ_NONE;
190 }
191 
192 static irqreturn_t tiadc_worker_h(int irq, void *private)
193 {
194 	struct iio_dev *indio_dev = private;
195 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
196 	int i, k, fifo1count, read;
197 	u16 *data = adc_dev->data;
198 
199 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
200 	for (k = 0; k < fifo1count; k = k + i) {
201 		for (i = 0; i < indio_dev->scan_bytes / 2; i++) {
202 			read = tiadc_readl(adc_dev, REG_FIFO1);
203 			data[i] = read & FIFOREAD_DATA_MASK;
204 		}
205 		iio_push_to_buffers(indio_dev, (u8 *)data);
206 	}
207 
208 	tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
209 	tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);
210 
211 	return IRQ_HANDLED;
212 }
213 
214 static void tiadc_dma_rx_complete(void *param)
215 {
216 	struct iio_dev *indio_dev = param;
217 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
218 	struct tiadc_dma *dma = &adc_dev->dma;
219 	u8 *data;
220 	int i;
221 
222 	data = dma->buf + dma->current_period * dma->period_size;
223 	dma->current_period = 1 - dma->current_period; /* swap the buffer ID */
224 
225 	for (i = 0; i < dma->period_size; i += indio_dev->scan_bytes) {
226 		iio_push_to_buffers(indio_dev, data);
227 		data += indio_dev->scan_bytes;
228 	}
229 }
230 
231 static int tiadc_start_dma(struct iio_dev *indio_dev)
232 {
233 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
234 	struct tiadc_dma *dma = &adc_dev->dma;
235 	struct dma_async_tx_descriptor *desc;
236 
237 	dma->current_period = 0; /* We start to fill period 0 */
238 
239 	/*
240 	 * Make the fifo thresh as the multiple of total number of
241 	 * channels enabled, so make sure that cyclic DMA period
242 	 * length is also a multiple of total number of channels
243 	 * enabled. This ensures that no invalid data is reported
244 	 * to the stack via iio_push_to_buffers().
245 	 */
246 	dma->fifo_thresh = rounddown(FIFO1_THRESHOLD + 1,
247 				     adc_dev->total_ch_enabled) - 1;
248 
249 	/* Make sure that period length is multiple of fifo thresh level */
250 	dma->period_size = rounddown(DMA_BUFFER_SIZE / 2,
251 				     (dma->fifo_thresh + 1) * sizeof(u16));
252 
253 	dma->conf.src_maxburst = dma->fifo_thresh + 1;
254 	dmaengine_slave_config(dma->chan, &dma->conf);
255 
256 	desc = dmaengine_prep_dma_cyclic(dma->chan, dma->addr,
257 					 dma->period_size * 2,
258 					 dma->period_size, DMA_DEV_TO_MEM,
259 					 DMA_PREP_INTERRUPT);
260 	if (!desc)
261 		return -EBUSY;
262 
263 	desc->callback = tiadc_dma_rx_complete;
264 	desc->callback_param = indio_dev;
265 
266 	dma->cookie = dmaengine_submit(desc);
267 
268 	dma_async_issue_pending(dma->chan);
269 
270 	tiadc_writel(adc_dev, REG_FIFO1THR, dma->fifo_thresh);
271 	tiadc_writel(adc_dev, REG_DMA1REQ, dma->fifo_thresh);
272 	tiadc_writel(adc_dev, REG_DMAENABLE_SET, DMA_FIFO1);
273 
274 	return 0;
275 }
276 
277 static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
278 {
279 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
280 	int i, fifo1count;
281 	int ret;
282 
283 	ret = tiadc_wait_idle(adc_dev);
284 	if (ret)
285 		return ret;
286 
287 	tiadc_writel(adc_dev, REG_IRQCLR,
288 		     IRQENB_FIFO1THRES | IRQENB_FIFO1OVRRUN |
289 		     IRQENB_FIFO1UNDRFLW);
290 
291 	/* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */
292 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
293 	for (i = 0; i < fifo1count; i++)
294 		tiadc_readl(adc_dev, REG_FIFO1);
295 
296 	return 0;
297 }
298 
299 static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
300 {
301 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
302 	struct tiadc_dma *dma = &adc_dev->dma;
303 	unsigned int irq_enable;
304 	unsigned int enb = 0;
305 	u8 bit;
306 
307 	tiadc_step_config(indio_dev);
308 	for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) {
309 		enb |= (get_adc_step_bit(adc_dev, bit) << 1);
310 		adc_dev->total_ch_enabled++;
311 	}
312 	adc_dev->buffer_en_ch_steps = enb;
313 
314 	if (dma->chan)
315 		tiadc_start_dma(indio_dev);
316 
317 	am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);
318 
319 	tiadc_writel(adc_dev, REG_IRQSTATUS,
320 		     IRQENB_FIFO1THRES | IRQENB_FIFO1OVRRUN |
321 		     IRQENB_FIFO1UNDRFLW);
322 
323 	irq_enable = IRQENB_FIFO1OVRRUN;
324 	if (!dma->chan)
325 		irq_enable |= IRQENB_FIFO1THRES;
326 	tiadc_writel(adc_dev,  REG_IRQENABLE, irq_enable);
327 
328 	return 0;
329 }
330 
331 static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
332 {
333 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
334 	struct tiadc_dma *dma = &adc_dev->dma;
335 	int fifo1count, i;
336 
337 	tiadc_writel(adc_dev, REG_IRQCLR,
338 		     IRQENB_FIFO1THRES | IRQENB_FIFO1OVRRUN |
339 		     IRQENB_FIFO1UNDRFLW);
340 	am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
341 	adc_dev->buffer_en_ch_steps = 0;
342 	adc_dev->total_ch_enabled = 0;
343 	if (dma->chan) {
344 		tiadc_writel(adc_dev, REG_DMAENABLE_CLEAR, 0x2);
345 		dmaengine_terminate_async(dma->chan);
346 	}
347 
348 	/* Flush FIFO of leftover data in the time it takes to disable adc */
349 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
350 	for (i = 0; i < fifo1count; i++)
351 		tiadc_readl(adc_dev, REG_FIFO1);
352 
353 	return 0;
354 }
355 
356 static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
357 {
358 	tiadc_step_config(indio_dev);
359 
360 	return 0;
361 }
362 
363 static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
364 	.preenable = &tiadc_buffer_preenable,
365 	.postenable = &tiadc_buffer_postenable,
366 	.predisable = &tiadc_buffer_predisable,
367 	.postdisable = &tiadc_buffer_postdisable,
368 };
369 
370 static int tiadc_iio_buffered_hardware_setup(struct device *dev,
371 					     struct iio_dev *indio_dev,
372 					     irqreturn_t (*pollfunc_bh)(int irq, void *p),
373 					     irqreturn_t (*pollfunc_th)(int irq, void *p),
374 					     int irq, unsigned long flags,
375 					     const struct iio_buffer_setup_ops *setup_ops)
376 {
377 	int ret;
378 
379 	ret = devm_iio_kfifo_buffer_setup(dev, indio_dev, setup_ops);
380 	if (ret)
381 		return ret;
382 
383 	return devm_request_threaded_irq(dev, irq, pollfunc_th, pollfunc_bh,
384 					 flags, indio_dev->name, indio_dev);
385 }
386 
387 static const char * const chan_name_ain[] = {
388 	"AIN0",
389 	"AIN1",
390 	"AIN2",
391 	"AIN3",
392 	"AIN4",
393 	"AIN5",
394 	"AIN6",
395 	"AIN7",
396 };
397 
398 static int tiadc_channel_init(struct device *dev, struct iio_dev *indio_dev,
399 			      int channels)
400 {
401 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
402 	struct iio_chan_spec *chan_array;
403 	struct iio_chan_spec *chan;
404 	int i;
405 
406 	indio_dev->num_channels = channels;
407 	chan_array = devm_kcalloc(dev, channels, sizeof(*chan_array),
408 				  GFP_KERNEL);
409 	if (!chan_array)
410 		return -ENOMEM;
411 
412 	chan = chan_array;
413 	for (i = 0; i < channels; i++, chan++) {
414 		chan->type = IIO_VOLTAGE;
415 		chan->indexed = 1;
416 		chan->channel = adc_dev->channel_line[i];
417 		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
418 		chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
419 		chan->datasheet_name = chan_name_ain[chan->channel];
420 		chan->scan_index = i;
421 		chan->scan_type.sign = 'u';
422 		chan->scan_type.realbits = 12;
423 		chan->scan_type.storagebits = 16;
424 	}
425 
426 	indio_dev->channels = chan_array;
427 
428 	return 0;
429 }
430 
431 static int tiadc_read_raw(struct iio_dev *indio_dev,
432 			  struct iio_chan_spec const *chan, int *val, int *val2,
433 			  long mask)
434 {
435 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
436 	int i, map_val;
437 	unsigned int fifo1count, read, stepid;
438 	bool found = false;
439 	u32 step_en;
440 	unsigned long timeout;
441 	int ret;
442 
443 	switch (mask) {
444 	case IIO_CHAN_INFO_RAW:
445 		break;
446 	case IIO_CHAN_INFO_SCALE:
447 		switch (chan->type) {
448 		case IIO_VOLTAGE:
449 			*val = 1800;
450 			*val2 = chan->scan_type.realbits;
451 			return IIO_VAL_FRACTIONAL_LOG2;
452 		default:
453 			return -EINVAL;
454 		}
455 		break;
456 	default:
457 		return -EINVAL;
458 	}
459 
460 	if (iio_buffer_enabled(indio_dev))
461 		return -EBUSY;
462 
463 	step_en = get_adc_chan_step_mask(adc_dev, chan);
464 	if (!step_en)
465 		return -EINVAL;
466 
467 	mutex_lock(&adc_dev->fifo1_lock);
468 
469 	ret = tiadc_wait_idle(adc_dev);
470 	if (ret)
471 		goto err_unlock;
472 
473 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
474 	while (fifo1count--)
475 		tiadc_readl(adc_dev, REG_FIFO1);
476 
477 	am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);
478 
479 	/* Wait for Fifo threshold interrupt */
480 	timeout = jiffies + msecs_to_jiffies(IDLE_TIMEOUT_MS * adc_dev->channels);
481 	while (1) {
482 		fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
483 		if (fifo1count)
484 			break;
485 
486 		if (time_after(jiffies, timeout)) {
487 			am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
488 			ret = -EAGAIN;
489 			goto err_unlock;
490 		}
491 	}
492 
493 	map_val = adc_dev->channel_step[chan->scan_index];
494 
495 	/*
496 	 * We check the complete FIFO. We programmed just one entry but in case
497 	 * something went wrong we left empty handed (-EAGAIN previously) and
498 	 * then the value apeared somehow in the FIFO we would have two entries.
499 	 * Therefore we read every item and keep only the latest version of the
500 	 * requested channel.
501 	 */
502 	for (i = 0; i < fifo1count; i++) {
503 		read = tiadc_readl(adc_dev, REG_FIFO1);
504 		stepid = read & FIFOREAD_CHNLID_MASK;
505 		stepid = stepid >> 0x10;
506 
507 		if (stepid == map_val) {
508 			read = read & FIFOREAD_DATA_MASK;
509 			found = true;
510 			*val = (u16)read;
511 		}
512 	}
513 
514 	am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
515 
516 	if (!found)
517 		ret = -EBUSY;
518 
519 err_unlock:
520 	mutex_unlock(&adc_dev->fifo1_lock);
521 	return ret ? ret : IIO_VAL_INT;
522 }
523 
524 static const struct iio_info tiadc_info = {
525 	.read_raw = &tiadc_read_raw,
526 };
527 
528 static int tiadc_request_dma(struct platform_device *pdev,
529 			     struct tiadc_device *adc_dev)
530 {
531 	struct tiadc_dma	*dma = &adc_dev->dma;
532 	dma_cap_mask_t		mask;
533 
534 	/* Default slave configuration parameters */
535 	dma->conf.direction = DMA_DEV_TO_MEM;
536 	dma->conf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
537 	dma->conf.src_addr = adc_dev->mfd_tscadc->tscadc_phys_base + REG_FIFO1;
538 
539 	dma_cap_zero(mask);
540 	dma_cap_set(DMA_CYCLIC, mask);
541 
542 	/* Get a channel for RX */
543 	dma->chan = dma_request_chan(adc_dev->mfd_tscadc->dev, "fifo1");
544 	if (IS_ERR(dma->chan)) {
545 		int ret = PTR_ERR(dma->chan);
546 
547 		dma->chan = NULL;
548 		return ret;
549 	}
550 
551 	/* RX buffer */
552 	dma->buf = dma_alloc_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
553 				      &dma->addr, GFP_KERNEL);
554 	if (!dma->buf)
555 		goto err;
556 
557 	return 0;
558 
559 err:
560 	dma_release_channel(dma->chan);
561 	return -ENOMEM;
562 }
563 
564 static int tiadc_parse_dt(struct platform_device *pdev,
565 			  struct tiadc_device *adc_dev)
566 {
567 	struct device_node *node = pdev->dev.of_node;
568 	struct property *prop;
569 	const __be32 *cur;
570 	int channels = 0;
571 	u32 val;
572 	int i;
573 
574 	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
575 		adc_dev->channel_line[channels] = val;
576 
577 		/* Set Default values for optional DT parameters */
578 		adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY;
579 		adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY;
580 		adc_dev->step_avg[channels] = 16;
581 
582 		channels++;
583 	}
584 
585 	adc_dev->channels = channels;
586 
587 	of_property_read_u32_array(node, "ti,chan-step-avg",
588 				   adc_dev->step_avg, channels);
589 	of_property_read_u32_array(node, "ti,chan-step-opendelay",
590 				   adc_dev->open_delay, channels);
591 	of_property_read_u32_array(node, "ti,chan-step-sampledelay",
592 				   adc_dev->sample_delay, channels);
593 
594 	for (i = 0; i < adc_dev->channels; i++) {
595 		int chan;
596 
597 		chan = adc_dev->channel_line[i];
598 
599 		if (adc_dev->step_avg[i] > STEPCONFIG_AVG_16) {
600 			dev_warn(&pdev->dev,
601 				 "chan %d: wrong step avg, truncated to %ld\n",
602 				 chan, STEPCONFIG_AVG_16);
603 			adc_dev->step_avg[i] = STEPCONFIG_AVG_16;
604 		}
605 
606 		if (adc_dev->open_delay[i] > STEPCONFIG_MAX_OPENDLY) {
607 			dev_warn(&pdev->dev,
608 				 "chan %d: wrong open delay, truncated to 0x%lX\n",
609 				 chan, STEPCONFIG_MAX_OPENDLY);
610 			adc_dev->open_delay[i] = STEPCONFIG_MAX_OPENDLY;
611 		}
612 
613 		if (adc_dev->sample_delay[i] > STEPCONFIG_MAX_SAMPLE) {
614 			dev_warn(&pdev->dev,
615 				 "chan %d: wrong sample delay, truncated to 0x%lX\n",
616 				 chan, STEPCONFIG_MAX_SAMPLE);
617 			adc_dev->sample_delay[i] = STEPCONFIG_MAX_SAMPLE;
618 		}
619 	}
620 
621 	return 0;
622 }
623 
624 static int tiadc_probe(struct platform_device *pdev)
625 {
626 	struct iio_dev		*indio_dev;
627 	struct tiadc_device	*adc_dev;
628 	struct device_node	*node = pdev->dev.of_node;
629 	int			err;
630 
631 	if (!node) {
632 		dev_err(&pdev->dev, "Could not find valid DT data.\n");
633 		return -EINVAL;
634 	}
635 
636 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc_dev));
637 	if (!indio_dev) {
638 		dev_err(&pdev->dev, "failed to allocate iio device\n");
639 		return -ENOMEM;
640 	}
641 	adc_dev = iio_priv(indio_dev);
642 
643 	adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
644 	tiadc_parse_dt(pdev, adc_dev);
645 
646 	indio_dev->name = dev_name(&pdev->dev);
647 	indio_dev->modes = INDIO_DIRECT_MODE;
648 	indio_dev->info = &tiadc_info;
649 
650 	tiadc_step_config(indio_dev);
651 	tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
652 	mutex_init(&adc_dev->fifo1_lock);
653 
654 	err = tiadc_channel_init(&pdev->dev, indio_dev, adc_dev->channels);
655 	if (err < 0)
656 		return err;
657 
658 	err = tiadc_iio_buffered_hardware_setup(&pdev->dev, indio_dev,
659 						&tiadc_worker_h,
660 						&tiadc_irq_h,
661 						adc_dev->mfd_tscadc->irq,
662 						IRQF_SHARED,
663 						&tiadc_buffer_setup_ops);
664 	if (err)
665 		return err;
666 
667 	err = iio_device_register(indio_dev);
668 	if (err)
669 		return err;
670 
671 	platform_set_drvdata(pdev, indio_dev);
672 
673 	err = tiadc_request_dma(pdev, adc_dev);
674 	if (err && err == -EPROBE_DEFER)
675 		goto err_dma;
676 
677 	return 0;
678 
679 err_dma:
680 	iio_device_unregister(indio_dev);
681 
682 	return err;
683 }
684 
685 static int tiadc_remove(struct platform_device *pdev)
686 {
687 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
688 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
689 	struct tiadc_dma *dma = &adc_dev->dma;
690 	u32 step_en;
691 
692 	if (dma->chan) {
693 		dma_free_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
694 				  dma->buf, dma->addr);
695 		dma_release_channel(dma->chan);
696 	}
697 	iio_device_unregister(indio_dev);
698 
699 	step_en = get_adc_step_mask(adc_dev);
700 	am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
701 
702 	return 0;
703 }
704 
705 static int __maybe_unused tiadc_suspend(struct device *dev)
706 {
707 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
708 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
709 	unsigned int idle;
710 
711 	idle = tiadc_readl(adc_dev, REG_CTRL);
712 	idle &= ~(CNTRLREG_SSENB);
713 	tiadc_writel(adc_dev, REG_CTRL, idle | CNTRLREG_POWERDOWN);
714 
715 	return 0;
716 }
717 
718 static int __maybe_unused tiadc_resume(struct device *dev)
719 {
720 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
721 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
722 	unsigned int restore;
723 
724 	/* Make sure ADC is powered up */
725 	restore = tiadc_readl(adc_dev, REG_CTRL);
726 	restore &= ~CNTRLREG_POWERDOWN;
727 	tiadc_writel(adc_dev, REG_CTRL, restore);
728 
729 	tiadc_step_config(indio_dev);
730 	am335x_tsc_se_set_cache(adc_dev->mfd_tscadc,
731 				adc_dev->buffer_en_ch_steps);
732 	return 0;
733 }
734 
735 static SIMPLE_DEV_PM_OPS(tiadc_pm_ops, tiadc_suspend, tiadc_resume);
736 
737 static const struct of_device_id ti_adc_dt_ids[] = {
738 	{ .compatible = "ti,am3359-adc", },
739 	{ .compatible = "ti,am4372-adc", },
740 	{ }
741 };
742 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
743 
744 static struct platform_driver tiadc_driver = {
745 	.driver = {
746 		.name   = "TI-am335x-adc",
747 		.pm	= &tiadc_pm_ops,
748 		.of_match_table = ti_adc_dt_ids,
749 	},
750 	.probe	= tiadc_probe,
751 	.remove	= tiadc_remove,
752 };
753 module_platform_driver(tiadc_driver);
754 
755 MODULE_DESCRIPTION("TI ADC controller driver");
756 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
757 MODULE_LICENSE("GPL");
758