xref: /openbmc/linux/drivers/iio/adc/ti_am335x_adc.c (revision 6db6b729)
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/iio/machine.h>
18 #include <linux/iio/driver.h>
19 #include <linux/iopoll.h>
20 
21 #include <linux/mfd/ti_am335x_tscadc.h>
22 #include <linux/iio/buffer.h>
23 #include <linux/iio/kfifo_buf.h>
24 
25 #include <linux/dmaengine.h>
26 #include <linux/dma-mapping.h>
27 
28 #define DMA_BUFFER_SIZE		SZ_2K
29 
30 struct tiadc_dma {
31 	struct dma_slave_config	conf;
32 	struct dma_chan		*chan;
33 	dma_addr_t		addr;
34 	dma_cookie_t		cookie;
35 	u8			*buf;
36 	int			current_period;
37 	int			period_size;
38 	u8			fifo_thresh;
39 };
40 
41 struct tiadc_device {
42 	struct ti_tscadc_dev *mfd_tscadc;
43 	struct tiadc_dma dma;
44 	struct mutex fifo1_lock; /* to protect fifo access */
45 	int channels;
46 	int total_ch_enabled;
47 	u8 channel_line[8];
48 	u8 channel_step[8];
49 	int buffer_en_ch_steps;
50 	u16 data[8];
51 	u32 open_delay[8], sample_delay[8], step_avg[8];
52 };
53 
54 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
55 {
56 	return readl(adc->mfd_tscadc->tscadc_base + reg);
57 }
58 
59 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg,
60 			 unsigned int val)
61 {
62 	writel(val, adc->mfd_tscadc->tscadc_base + reg);
63 }
64 
65 static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
66 {
67 	u32 step_en;
68 
69 	step_en = ((1 << adc_dev->channels) - 1);
70 	step_en <<= TOTAL_STEPS - adc_dev->channels + 1;
71 	return step_en;
72 }
73 
74 static u32 get_adc_chan_step_mask(struct tiadc_device *adc_dev,
75 				  struct iio_chan_spec const *chan)
76 {
77 	int i;
78 
79 	for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
80 		if (chan->channel == adc_dev->channel_line[i]) {
81 			u32 step;
82 
83 			step = adc_dev->channel_step[i];
84 			/* +1 for the charger */
85 			return 1 << (step + 1);
86 		}
87 	}
88 	WARN_ON(1);
89 	return 0;
90 }
91 
92 static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan)
93 {
94 	return 1 << adc_dev->channel_step[chan];
95 }
96 
97 static int tiadc_wait_idle(struct tiadc_device *adc_dev)
98 {
99 	u32 val;
100 
101 	return readl_poll_timeout(adc_dev->mfd_tscadc->tscadc_base + REG_ADCFSM,
102 				  val, !(val & SEQ_STATUS), 10,
103 				  IDLE_TIMEOUT_MS * 1000 * adc_dev->channels);
104 }
105 
106 static void tiadc_step_config(struct iio_dev *indio_dev)
107 {
108 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
109 	unsigned int stepconfig;
110 	int i, steps = 0;
111 
112 	/*
113 	 * There are 16 configurable steps and 8 analog input
114 	 * lines available which are shared between Touchscreen and ADC.
115 	 *
116 	 * Steps forwards i.e. from 0 towards 16 are used by ADC
117 	 * depending on number of input lines needed.
118 	 * Channel would represent which analog input
119 	 * needs to be given to ADC to digitalize data.
120 	 */
121 	for (i = 0; i < adc_dev->channels; i++) {
122 		int chan;
123 
124 		chan = adc_dev->channel_line[i];
125 
126 		if (adc_dev->step_avg[i])
127 			stepconfig = STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) |
128 				     STEPCONFIG_FIFO1;
129 		else
130 			stepconfig = STEPCONFIG_FIFO1;
131 
132 		if (iio_buffer_enabled(indio_dev))
133 			stepconfig |= STEPCONFIG_MODE_SWCNT;
134 
135 		tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
136 			     stepconfig | STEPCONFIG_INP(chan) |
137 			     STEPCONFIG_INM_ADCREFM | STEPCONFIG_RFP_VREFP |
138 			     STEPCONFIG_RFM_VREFN);
139 
140 		tiadc_writel(adc_dev, REG_STEPDELAY(steps),
141 			     STEPDELAY_OPEN(adc_dev->open_delay[i]) |
142 			     STEPDELAY_SAMPLE(adc_dev->sample_delay[i]));
143 
144 		adc_dev->channel_step[i] = steps;
145 		steps++;
146 	}
147 }
148 
149 static irqreturn_t tiadc_irq_h(int irq, void *private)
150 {
151 	struct iio_dev *indio_dev = private;
152 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
153 	unsigned int status, config, adc_fsm;
154 	unsigned short count = 0;
155 
156 	status = tiadc_readl(adc_dev, REG_IRQSTATUS);
157 
158 	/*
159 	 * ADC and touchscreen share the IRQ line.
160 	 * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only
161 	 */
162 	if (status & IRQENB_FIFO1OVRRUN) {
163 		/* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */
164 		config = tiadc_readl(adc_dev, REG_CTRL);
165 		config &= ~(CNTRLREG_SSENB);
166 		tiadc_writel(adc_dev, REG_CTRL, config);
167 		tiadc_writel(adc_dev, REG_IRQSTATUS,
168 			     IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW |
169 			     IRQENB_FIFO1THRES);
170 
171 		/*
172 		 * Wait for the idle state.
173 		 * ADC needs to finish the current conversion
174 		 * before disabling the module
175 		 */
176 		do {
177 			adc_fsm = tiadc_readl(adc_dev, REG_ADCFSM);
178 		} while (adc_fsm != 0x10 && count++ < 100);
179 
180 		tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_SSENB));
181 		return IRQ_HANDLED;
182 	} else if (status & IRQENB_FIFO1THRES) {
183 		/* Disable irq and wake worker thread */
184 		tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES);
185 		return IRQ_WAKE_THREAD;
186 	}
187 
188 	return IRQ_NONE;
189 }
190 
191 static irqreturn_t tiadc_worker_h(int irq, void *private)
192 {
193 	struct iio_dev *indio_dev = private;
194 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
195 	int i, k, fifo1count, read;
196 	u16 *data = adc_dev->data;
197 
198 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
199 	for (k = 0; k < fifo1count; k = k + i) {
200 		for (i = 0; i < indio_dev->scan_bytes / 2; i++) {
201 			read = tiadc_readl(adc_dev, REG_FIFO1);
202 			data[i] = read & FIFOREAD_DATA_MASK;
203 		}
204 		iio_push_to_buffers(indio_dev, (u8 *)data);
205 	}
206 
207 	tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES);
208 	tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);
209 
210 	return IRQ_HANDLED;
211 }
212 
213 static void tiadc_dma_rx_complete(void *param)
214 {
215 	struct iio_dev *indio_dev = param;
216 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
217 	struct tiadc_dma *dma = &adc_dev->dma;
218 	u8 *data;
219 	int i;
220 
221 	data = dma->buf + dma->current_period * dma->period_size;
222 	dma->current_period = 1 - dma->current_period; /* swap the buffer ID */
223 
224 	for (i = 0; i < dma->period_size; i += indio_dev->scan_bytes) {
225 		iio_push_to_buffers(indio_dev, data);
226 		data += indio_dev->scan_bytes;
227 	}
228 }
229 
230 static int tiadc_start_dma(struct iio_dev *indio_dev)
231 {
232 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
233 	struct tiadc_dma *dma = &adc_dev->dma;
234 	struct dma_async_tx_descriptor *desc;
235 
236 	dma->current_period = 0; /* We start to fill period 0 */
237 
238 	/*
239 	 * Make the fifo thresh as the multiple of total number of
240 	 * channels enabled, so make sure that cyclic DMA period
241 	 * length is also a multiple of total number of channels
242 	 * enabled. This ensures that no invalid data is reported
243 	 * to the stack via iio_push_to_buffers().
244 	 */
245 	dma->fifo_thresh = rounddown(FIFO1_THRESHOLD + 1,
246 				     adc_dev->total_ch_enabled) - 1;
247 
248 	/* Make sure that period length is multiple of fifo thresh level */
249 	dma->period_size = rounddown(DMA_BUFFER_SIZE / 2,
250 				     (dma->fifo_thresh + 1) * sizeof(u16));
251 
252 	dma->conf.src_maxburst = dma->fifo_thresh + 1;
253 	dmaengine_slave_config(dma->chan, &dma->conf);
254 
255 	desc = dmaengine_prep_dma_cyclic(dma->chan, dma->addr,
256 					 dma->period_size * 2,
257 					 dma->period_size, DMA_DEV_TO_MEM,
258 					 DMA_PREP_INTERRUPT);
259 	if (!desc)
260 		return -EBUSY;
261 
262 	desc->callback = tiadc_dma_rx_complete;
263 	desc->callback_param = indio_dev;
264 
265 	dma->cookie = dmaengine_submit(desc);
266 
267 	dma_async_issue_pending(dma->chan);
268 
269 	tiadc_writel(adc_dev, REG_FIFO1THR, dma->fifo_thresh);
270 	tiadc_writel(adc_dev, REG_DMA1REQ, dma->fifo_thresh);
271 	tiadc_writel(adc_dev, REG_DMAENABLE_SET, DMA_FIFO1);
272 
273 	return 0;
274 }
275 
276 static int tiadc_buffer_preenable(struct iio_dev *indio_dev)
277 {
278 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
279 	int i, fifo1count;
280 	int ret;
281 
282 	ret = tiadc_wait_idle(adc_dev);
283 	if (ret)
284 		return ret;
285 
286 	tiadc_writel(adc_dev, REG_IRQCLR,
287 		     IRQENB_FIFO1THRES | IRQENB_FIFO1OVRRUN |
288 		     IRQENB_FIFO1UNDRFLW);
289 
290 	/* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */
291 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
292 	for (i = 0; i < fifo1count; i++)
293 		tiadc_readl(adc_dev, REG_FIFO1);
294 
295 	return 0;
296 }
297 
298 static int tiadc_buffer_postenable(struct iio_dev *indio_dev)
299 {
300 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
301 	struct tiadc_dma *dma = &adc_dev->dma;
302 	unsigned int irq_enable;
303 	unsigned int enb = 0;
304 	u8 bit;
305 
306 	tiadc_step_config(indio_dev);
307 	for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) {
308 		enb |= (get_adc_step_bit(adc_dev, bit) << 1);
309 		adc_dev->total_ch_enabled++;
310 	}
311 	adc_dev->buffer_en_ch_steps = enb;
312 
313 	if (dma->chan)
314 		tiadc_start_dma(indio_dev);
315 
316 	am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb);
317 
318 	tiadc_writel(adc_dev, REG_IRQSTATUS,
319 		     IRQENB_FIFO1THRES | IRQENB_FIFO1OVRRUN |
320 		     IRQENB_FIFO1UNDRFLW);
321 
322 	irq_enable = IRQENB_FIFO1OVRRUN;
323 	if (!dma->chan)
324 		irq_enable |= IRQENB_FIFO1THRES;
325 	tiadc_writel(adc_dev,  REG_IRQENABLE, irq_enable);
326 
327 	return 0;
328 }
329 
330 static int tiadc_buffer_predisable(struct iio_dev *indio_dev)
331 {
332 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
333 	struct tiadc_dma *dma = &adc_dev->dma;
334 	int fifo1count, i;
335 
336 	tiadc_writel(adc_dev, REG_IRQCLR,
337 		     IRQENB_FIFO1THRES | IRQENB_FIFO1OVRRUN |
338 		     IRQENB_FIFO1UNDRFLW);
339 	am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps);
340 	adc_dev->buffer_en_ch_steps = 0;
341 	adc_dev->total_ch_enabled = 0;
342 	if (dma->chan) {
343 		tiadc_writel(adc_dev, REG_DMAENABLE_CLEAR, 0x2);
344 		dmaengine_terminate_async(dma->chan);
345 	}
346 
347 	/* Flush FIFO of leftover data in the time it takes to disable adc */
348 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
349 	for (i = 0; i < fifo1count; i++)
350 		tiadc_readl(adc_dev, REG_FIFO1);
351 
352 	return 0;
353 }
354 
355 static int tiadc_buffer_postdisable(struct iio_dev *indio_dev)
356 {
357 	tiadc_step_config(indio_dev);
358 
359 	return 0;
360 }
361 
362 static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
363 	.preenable = &tiadc_buffer_preenable,
364 	.postenable = &tiadc_buffer_postenable,
365 	.predisable = &tiadc_buffer_predisable,
366 	.postdisable = &tiadc_buffer_postdisable,
367 };
368 
369 static int tiadc_iio_buffered_hardware_setup(struct device *dev,
370 					     struct iio_dev *indio_dev,
371 					     irqreturn_t (*pollfunc_bh)(int irq, void *p),
372 					     irqreturn_t (*pollfunc_th)(int irq, void *p),
373 					     int irq, unsigned long flags,
374 					     const struct iio_buffer_setup_ops *setup_ops)
375 {
376 	int ret;
377 
378 	ret = devm_iio_kfifo_buffer_setup(dev, indio_dev, setup_ops);
379 	if (ret)
380 		return ret;
381 
382 	return devm_request_threaded_irq(dev, irq, pollfunc_th, pollfunc_bh,
383 					 flags, indio_dev->name, indio_dev);
384 }
385 
386 static const char * const chan_name_ain[] = {
387 	"AIN0",
388 	"AIN1",
389 	"AIN2",
390 	"AIN3",
391 	"AIN4",
392 	"AIN5",
393 	"AIN6",
394 	"AIN7",
395 };
396 
397 static int tiadc_channel_init(struct device *dev, struct iio_dev *indio_dev,
398 			      int channels)
399 {
400 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
401 	struct iio_chan_spec *chan_array;
402 	struct iio_chan_spec *chan;
403 	int i;
404 
405 	indio_dev->num_channels = channels;
406 	chan_array = devm_kcalloc(dev, channels, sizeof(*chan_array),
407 				  GFP_KERNEL);
408 	if (!chan_array)
409 		return -ENOMEM;
410 
411 	chan = chan_array;
412 	for (i = 0; i < channels; i++, chan++) {
413 		chan->type = IIO_VOLTAGE;
414 		chan->indexed = 1;
415 		chan->channel = adc_dev->channel_line[i];
416 		chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
417 		chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE);
418 		chan->datasheet_name = chan_name_ain[chan->channel];
419 		chan->scan_index = i;
420 		chan->scan_type.sign = 'u';
421 		chan->scan_type.realbits = 12;
422 		chan->scan_type.storagebits = 16;
423 	}
424 
425 	indio_dev->channels = chan_array;
426 
427 	return 0;
428 }
429 
430 static int tiadc_read_raw(struct iio_dev *indio_dev,
431 			  struct iio_chan_spec const *chan, int *val, int *val2,
432 			  long mask)
433 {
434 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
435 	int i, map_val;
436 	unsigned int fifo1count, read, stepid;
437 	bool found = false;
438 	u32 step_en;
439 	unsigned long timeout;
440 	int ret;
441 
442 	switch (mask) {
443 	case IIO_CHAN_INFO_RAW:
444 		break;
445 	case IIO_CHAN_INFO_SCALE:
446 		switch (chan->type) {
447 		case IIO_VOLTAGE:
448 			*val = 1800;
449 			*val2 = chan->scan_type.realbits;
450 			return IIO_VAL_FRACTIONAL_LOG2;
451 		default:
452 			return -EINVAL;
453 		}
454 		break;
455 	default:
456 		return -EINVAL;
457 	}
458 
459 	if (iio_buffer_enabled(indio_dev))
460 		return -EBUSY;
461 
462 	step_en = get_adc_chan_step_mask(adc_dev, chan);
463 	if (!step_en)
464 		return -EINVAL;
465 
466 	mutex_lock(&adc_dev->fifo1_lock);
467 
468 	ret = tiadc_wait_idle(adc_dev);
469 	if (ret)
470 		goto err_unlock;
471 
472 	fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
473 	while (fifo1count--)
474 		tiadc_readl(adc_dev, REG_FIFO1);
475 
476 	am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en);
477 
478 	/* Wait for Fifo threshold interrupt */
479 	timeout = jiffies + msecs_to_jiffies(IDLE_TIMEOUT_MS * adc_dev->channels);
480 	while (1) {
481 		fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
482 		if (fifo1count)
483 			break;
484 
485 		if (time_after(jiffies, timeout)) {
486 			am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
487 			ret = -EAGAIN;
488 			goto err_unlock;
489 		}
490 	}
491 
492 	map_val = adc_dev->channel_step[chan->scan_index];
493 
494 	/*
495 	 * We check the complete FIFO. We programmed just one entry but in case
496 	 * something went wrong we left empty handed (-EAGAIN previously) and
497 	 * then the value apeared somehow in the FIFO we would have two entries.
498 	 * Therefore we read every item and keep only the latest version of the
499 	 * requested channel.
500 	 */
501 	for (i = 0; i < fifo1count; i++) {
502 		read = tiadc_readl(adc_dev, REG_FIFO1);
503 		stepid = read & FIFOREAD_CHNLID_MASK;
504 		stepid = stepid >> 0x10;
505 
506 		if (stepid == map_val) {
507 			read = read & FIFOREAD_DATA_MASK;
508 			found = true;
509 			*val = (u16)read;
510 		}
511 	}
512 
513 	am335x_tsc_se_adc_done(adc_dev->mfd_tscadc);
514 
515 	if (!found)
516 		ret = -EBUSY;
517 
518 err_unlock:
519 	mutex_unlock(&adc_dev->fifo1_lock);
520 	return ret ? ret : IIO_VAL_INT;
521 }
522 
523 static const struct iio_info tiadc_info = {
524 	.read_raw = &tiadc_read_raw,
525 };
526 
527 static int tiadc_request_dma(struct platform_device *pdev,
528 			     struct tiadc_device *adc_dev)
529 {
530 	struct tiadc_dma	*dma = &adc_dev->dma;
531 	dma_cap_mask_t		mask;
532 
533 	/* Default slave configuration parameters */
534 	dma->conf.direction = DMA_DEV_TO_MEM;
535 	dma->conf.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
536 	dma->conf.src_addr = adc_dev->mfd_tscadc->tscadc_phys_base + REG_FIFO1;
537 
538 	dma_cap_zero(mask);
539 	dma_cap_set(DMA_CYCLIC, mask);
540 
541 	/* Get a channel for RX */
542 	dma->chan = dma_request_chan(adc_dev->mfd_tscadc->dev, "fifo1");
543 	if (IS_ERR(dma->chan)) {
544 		int ret = PTR_ERR(dma->chan);
545 
546 		dma->chan = NULL;
547 		return ret;
548 	}
549 
550 	/* RX buffer */
551 	dma->buf = dma_alloc_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
552 				      &dma->addr, GFP_KERNEL);
553 	if (!dma->buf)
554 		goto err;
555 
556 	return 0;
557 
558 err:
559 	dma_release_channel(dma->chan);
560 	return -ENOMEM;
561 }
562 
563 static int tiadc_parse_dt(struct platform_device *pdev,
564 			  struct tiadc_device *adc_dev)
565 {
566 	struct device_node *node = pdev->dev.of_node;
567 	struct property *prop;
568 	const __be32 *cur;
569 	int channels = 0;
570 	u32 val;
571 	int i;
572 
573 	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
574 		adc_dev->channel_line[channels] = val;
575 
576 		/* Set Default values for optional DT parameters */
577 		adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY;
578 		adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY;
579 		adc_dev->step_avg[channels] = 16;
580 
581 		channels++;
582 	}
583 
584 	adc_dev->channels = channels;
585 
586 	of_property_read_u32_array(node, "ti,chan-step-avg",
587 				   adc_dev->step_avg, channels);
588 	of_property_read_u32_array(node, "ti,chan-step-opendelay",
589 				   adc_dev->open_delay, channels);
590 	of_property_read_u32_array(node, "ti,chan-step-sampledelay",
591 				   adc_dev->sample_delay, channels);
592 
593 	for (i = 0; i < adc_dev->channels; i++) {
594 		int chan;
595 
596 		chan = adc_dev->channel_line[i];
597 
598 		if (adc_dev->step_avg[i] > STEPCONFIG_AVG_16) {
599 			dev_warn(&pdev->dev,
600 				 "chan %d: wrong step avg, truncated to %ld\n",
601 				 chan, STEPCONFIG_AVG_16);
602 			adc_dev->step_avg[i] = STEPCONFIG_AVG_16;
603 		}
604 
605 		if (adc_dev->open_delay[i] > STEPCONFIG_MAX_OPENDLY) {
606 			dev_warn(&pdev->dev,
607 				 "chan %d: wrong open delay, truncated to 0x%lX\n",
608 				 chan, STEPCONFIG_MAX_OPENDLY);
609 			adc_dev->open_delay[i] = STEPCONFIG_MAX_OPENDLY;
610 		}
611 
612 		if (adc_dev->sample_delay[i] > STEPCONFIG_MAX_SAMPLE) {
613 			dev_warn(&pdev->dev,
614 				 "chan %d: wrong sample delay, truncated to 0x%lX\n",
615 				 chan, STEPCONFIG_MAX_SAMPLE);
616 			adc_dev->sample_delay[i] = STEPCONFIG_MAX_SAMPLE;
617 		}
618 	}
619 
620 	return 0;
621 }
622 
623 static int tiadc_probe(struct platform_device *pdev)
624 {
625 	struct iio_dev		*indio_dev;
626 	struct tiadc_device	*adc_dev;
627 	struct device_node	*node = pdev->dev.of_node;
628 	int			err;
629 
630 	if (!node) {
631 		dev_err(&pdev->dev, "Could not find valid DT data.\n");
632 		return -EINVAL;
633 	}
634 
635 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc_dev));
636 	if (!indio_dev) {
637 		dev_err(&pdev->dev, "failed to allocate iio device\n");
638 		return -ENOMEM;
639 	}
640 	adc_dev = iio_priv(indio_dev);
641 
642 	adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
643 	tiadc_parse_dt(pdev, adc_dev);
644 
645 	indio_dev->name = dev_name(&pdev->dev);
646 	indio_dev->modes = INDIO_DIRECT_MODE;
647 	indio_dev->info = &tiadc_info;
648 
649 	tiadc_step_config(indio_dev);
650 	tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
651 	mutex_init(&adc_dev->fifo1_lock);
652 
653 	err = tiadc_channel_init(&pdev->dev, indio_dev, adc_dev->channels);
654 	if (err < 0)
655 		return err;
656 
657 	err = tiadc_iio_buffered_hardware_setup(&pdev->dev, indio_dev,
658 						&tiadc_worker_h,
659 						&tiadc_irq_h,
660 						adc_dev->mfd_tscadc->irq,
661 						IRQF_SHARED,
662 						&tiadc_buffer_setup_ops);
663 	if (err)
664 		return err;
665 
666 	err = iio_device_register(indio_dev);
667 	if (err)
668 		return err;
669 
670 	platform_set_drvdata(pdev, indio_dev);
671 
672 	err = tiadc_request_dma(pdev, adc_dev);
673 	if (err && err == -EPROBE_DEFER)
674 		goto err_dma;
675 
676 	return 0;
677 
678 err_dma:
679 	iio_device_unregister(indio_dev);
680 
681 	return err;
682 }
683 
684 static int tiadc_remove(struct platform_device *pdev)
685 {
686 	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
687 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
688 	struct tiadc_dma *dma = &adc_dev->dma;
689 	u32 step_en;
690 
691 	if (dma->chan) {
692 		dma_free_coherent(dma->chan->device->dev, DMA_BUFFER_SIZE,
693 				  dma->buf, dma->addr);
694 		dma_release_channel(dma->chan);
695 	}
696 	iio_device_unregister(indio_dev);
697 
698 	step_en = get_adc_step_mask(adc_dev);
699 	am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en);
700 
701 	return 0;
702 }
703 
704 static int tiadc_suspend(struct device *dev)
705 {
706 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
707 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
708 	unsigned int idle;
709 
710 	idle = tiadc_readl(adc_dev, REG_CTRL);
711 	idle &= ~(CNTRLREG_SSENB);
712 	tiadc_writel(adc_dev, REG_CTRL, idle | CNTRLREG_POWERDOWN);
713 
714 	return 0;
715 }
716 
717 static int tiadc_resume(struct device *dev)
718 {
719 	struct iio_dev *indio_dev = dev_get_drvdata(dev);
720 	struct tiadc_device *adc_dev = iio_priv(indio_dev);
721 	unsigned int restore;
722 
723 	/* Make sure ADC is powered up */
724 	restore = tiadc_readl(adc_dev, REG_CTRL);
725 	restore &= ~CNTRLREG_POWERDOWN;
726 	tiadc_writel(adc_dev, REG_CTRL, restore);
727 
728 	tiadc_step_config(indio_dev);
729 	am335x_tsc_se_set_cache(adc_dev->mfd_tscadc,
730 				adc_dev->buffer_en_ch_steps);
731 	return 0;
732 }
733 
734 static DEFINE_SIMPLE_DEV_PM_OPS(tiadc_pm_ops, tiadc_suspend, tiadc_resume);
735 
736 static const struct of_device_id ti_adc_dt_ids[] = {
737 	{ .compatible = "ti,am3359-adc", },
738 	{ .compatible = "ti,am4372-adc", },
739 	{ }
740 };
741 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids);
742 
743 static struct platform_driver tiadc_driver = {
744 	.driver = {
745 		.name   = "TI-am335x-adc",
746 		.pm	= pm_sleep_ptr(&tiadc_pm_ops),
747 		.of_match_table = ti_adc_dt_ids,
748 	},
749 	.probe	= tiadc_probe,
750 	.remove	= tiadc_remove,
751 };
752 module_platform_driver(tiadc_driver);
753 
754 MODULE_DESCRIPTION("TI ADC controller driver");
755 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
756 MODULE_LICENSE("GPL");
757