2 * Freescale i.MX28 LRADC driver
4 * Copyright (c) 2012 DENX Software Engineering, GmbH.
5 * Marek Vasut <marex@denx.de>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
18 #include <linux/err.h>
19 #include <linux/interrupt.h>
20 #include <linux/device.h>
21 #include <linux/kernel.h>
22 #include <linux/slab.h>
24 #include <linux/of_device.h>
25 #include <linux/sysfs.h>
26 #include <linux/list.h>
28 #include <linux/module.h>
29 #include <linux/platform_device.h>
30 #include <linux/spinlock.h>
31 #include <linux/wait.h>
32 #include <linux/sched.h>
33 #include <linux/stmp_device.h>
34 #include <linux/bitops.h>
35 #include <linux/completion.h>
36 #include <linux/delay.h>
37 #include <linux/input.h>
38 #include <linux/clk.h>
40 #include <linux/iio/iio.h>
41 #include <linux/iio/buffer.h>
42 #include <linux/iio/trigger.h>
43 #include <linux/iio/trigger_consumer.h>
44 #include <linux/iio/triggered_buffer.h>
46 #define DRIVER_NAME "mxs-lradc"
48 #define LRADC_MAX_DELAY_CHANS 4
49 #define LRADC_MAX_MAPPED_CHANS 8
50 #define LRADC_MAX_TOTAL_CHANS 16
52 #define LRADC_DELAY_TIMER_HZ 2000
55 * Make this runtime configurable if necessary. Currently, if the buffered mode
56 * is enabled, the LRADC takes LRADC_DELAY_TIMER_LOOP samples of data before
57 * triggering IRQ. The sampling happens every (LRADC_DELAY_TIMER_PER / 2000)
58 * seconds. The result is that the samples arrive every 500mS.
60 #define LRADC_DELAY_TIMER_PER 200
61 #define LRADC_DELAY_TIMER_LOOP 5
64 * Once the pen touches the touchscreen, the touchscreen switches from
65 * IRQ-driven mode to polling mode to prevent interrupt storm. The polling
66 * is realized by worker thread, which is called every 20 or so milliseconds.
67 * This gives the touchscreen enough fluence and does not strain the system
70 #define LRADC_TS_SAMPLE_DELAY_MS 5
73 * The LRADC reads the following amount of samples from each touchscreen
74 * channel and the driver then computes avarage of these.
76 #define LRADC_TS_SAMPLE_AMOUNT 4
83 static const char * const mx23_lradc_irq_names[] = {
84 "mxs-lradc-touchscreen",
95 static const char * const mx28_lradc_irq_names[] = {
96 "mxs-lradc-touchscreen",
100 "mxs-lradc-channel1",
101 "mxs-lradc-channel2",
102 "mxs-lradc-channel3",
103 "mxs-lradc-channel4",
104 "mxs-lradc-channel5",
105 "mxs-lradc-channel6",
106 "mxs-lradc-channel7",
111 struct mxs_lradc_of_config {
113 const char * const *irq_name;
116 static const struct mxs_lradc_of_config mxs_lradc_of_config[] = {
118 .irq_count = ARRAY_SIZE(mx23_lradc_irq_names),
119 .irq_name = mx23_lradc_irq_names,
122 .irq_count = ARRAY_SIZE(mx28_lradc_irq_names),
123 .irq_name = mx28_lradc_irq_names,
128 MXS_LRADC_TOUCHSCREEN_NONE = 0,
129 MXS_LRADC_TOUCHSCREEN_4WIRE,
130 MXS_LRADC_TOUCHSCREEN_5WIRE,
141 struct iio_trigger *trig;
145 struct completion completion;
148 * Touchscreen LRADC channels receives a private slot in the CTRL4
149 * register, the slot #7. Therefore only 7 slots instead of 8 in the
150 * CTRL4 register can be mapped to LRADC channels when using the
153 * Furthermore, certain LRADC channels are shared between touchscreen
154 * and/or touch-buttons and generic LRADC block. Therefore when using
155 * either of these, these channels are not available for the regular
156 * sampling. The shared channels are as follows:
158 * CH0 -- Touch button #0
159 * CH1 -- Touch button #1
160 * CH2 -- Touch screen XPUL
161 * CH3 -- Touch screen YPLL
162 * CH4 -- Touch screen XNUL
163 * CH5 -- Touch screen YNLR
164 * CH6 -- Touch screen WIPER (5-wire only)
166 * The bitfields below represents which parts of the LRADC block are
167 * switched into special mode of operation. These channels can not
168 * be sampled as regular LRADC channels. The driver will refuse any
169 * attempt to sample these channels.
171 #define CHAN_MASK_TOUCHBUTTON (0x3 << 0)
172 #define CHAN_MASK_TOUCHSCREEN_4WIRE (0xf << 2)
173 #define CHAN_MASK_TOUCHSCREEN_5WIRE (0x1f << 2)
174 enum mxs_lradc_ts use_touchscreen;
175 bool stop_touchscreen;
176 bool use_touchbutton;
178 struct input_dev *ts_input;
179 struct work_struct ts_work;
182 #define LRADC_CTRL0 0x00
183 #define LRADC_CTRL0_TOUCH_DETECT_ENABLE (1 << 23)
184 #define LRADC_CTRL0_TOUCH_SCREEN_TYPE (1 << 22)
185 #define LRADC_CTRL0_YNNSW /* YM */ (1 << 21)
186 #define LRADC_CTRL0_YPNSW /* YP */ (1 << 20)
187 #define LRADC_CTRL0_YPPSW /* YP */ (1 << 19)
188 #define LRADC_CTRL0_XNNSW /* XM */ (1 << 18)
189 #define LRADC_CTRL0_XNPSW /* XM */ (1 << 17)
190 #define LRADC_CTRL0_XPPSW /* XP */ (1 << 16)
191 #define LRADC_CTRL0_PLATE_MASK (0x3f << 16)
193 #define LRADC_CTRL1 0x10
194 #define LRADC_CTRL1_TOUCH_DETECT_IRQ_EN (1 << 24)
195 #define LRADC_CTRL1_LRADC_IRQ_EN(n) (1 << ((n) + 16))
196 #define LRADC_CTRL1_LRADC_IRQ_EN_MASK (0x1fff << 16)
197 #define LRADC_CTRL1_LRADC_IRQ_EN_OFFSET 16
198 #define LRADC_CTRL1_TOUCH_DETECT_IRQ (1 << 8)
199 #define LRADC_CTRL1_LRADC_IRQ(n) (1 << (n))
200 #define LRADC_CTRL1_LRADC_IRQ_MASK 0x1fff
201 #define LRADC_CTRL1_LRADC_IRQ_OFFSET 0
203 #define LRADC_CTRL2 0x20
204 #define LRADC_CTRL2_TEMPSENSE_PWD (1 << 15)
206 #define LRADC_STATUS 0x40
207 #define LRADC_STATUS_TOUCH_DETECT_RAW (1 << 0)
209 #define LRADC_CH(n) (0x50 + (0x10 * (n)))
210 #define LRADC_CH_ACCUMULATE (1 << 29)
211 #define LRADC_CH_NUM_SAMPLES_MASK (0x1f << 24)
212 #define LRADC_CH_NUM_SAMPLES_OFFSET 24
213 #define LRADC_CH_VALUE_MASK 0x3ffff
214 #define LRADC_CH_VALUE_OFFSET 0
216 #define LRADC_DELAY(n) (0xd0 + (0x10 * (n)))
217 #define LRADC_DELAY_TRIGGER_LRADCS_MASK (0xff << 24)
218 #define LRADC_DELAY_TRIGGER_LRADCS_OFFSET 24
219 #define LRADC_DELAY_KICK (1 << 20)
220 #define LRADC_DELAY_TRIGGER_DELAYS_MASK (0xf << 16)
221 #define LRADC_DELAY_TRIGGER_DELAYS_OFFSET 16
222 #define LRADC_DELAY_LOOP_COUNT_MASK (0x1f << 11)
223 #define LRADC_DELAY_LOOP_COUNT_OFFSET 11
224 #define LRADC_DELAY_DELAY_MASK 0x7ff
225 #define LRADC_DELAY_DELAY_OFFSET 0
227 #define LRADC_CTRL4 0x140
228 #define LRADC_CTRL4_LRADCSELECT_MASK(n) (0xf << ((n) * 4))
229 #define LRADC_CTRL4_LRADCSELECT_OFFSET(n) ((n) * 4)
231 #define LRADC_RESOLUTION 12
232 #define LRADC_SINGLE_SAMPLE_MASK ((1 << LRADC_RESOLUTION) - 1)
237 static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
238 const struct iio_chan_spec *chan,
239 int *val, int *val2, long m)
241 struct mxs_lradc *lradc = iio_priv(iio_dev);
244 if (m != IIO_CHAN_INFO_RAW)
247 /* Check for invalid channel */
248 if (chan->channel > LRADC_MAX_TOTAL_CHANS)
252 * See if there is no buffered operation in progess. If there is, simply
253 * bail out. This can be improved to support both buffered and raw IO at
254 * the same time, yet the code becomes horribly complicated. Therefore I
255 * applied KISS principle here.
257 ret = mutex_trylock(&lradc->lock);
261 INIT_COMPLETION(lradc->completion);
264 * No buffered operation in progress, map the channel and trigger it.
265 * Virtual channel 0 is always used here as the others are always not
266 * used if doing raw sampling.
268 writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
269 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
270 writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
272 /* Clean the slot's previous content, then set new one. */
273 writel(LRADC_CTRL4_LRADCSELECT_MASK(0),
274 lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
275 writel(chan->channel, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
277 writel(0, lradc->base + LRADC_CH(0));
279 /* Enable the IRQ and start sampling the channel. */
280 writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
281 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
282 writel(1 << 0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
284 /* Wait for completion on the channel, 1 second max. */
285 ret = wait_for_completion_killable_timeout(&lradc->completion, HZ);
292 *val = readl(lradc->base + LRADC_CH(0)) & LRADC_CH_VALUE_MASK;
296 writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
297 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
299 mutex_unlock(&lradc->lock);
304 static const struct iio_info mxs_lradc_iio_info = {
305 .driver_module = THIS_MODULE,
306 .read_raw = mxs_lradc_read_raw,
310 * Touchscreen handling
312 enum lradc_ts_plate {
315 LRADC_SAMPLE_PRESSURE,
318 static int mxs_lradc_ts_touched(struct mxs_lradc *lradc)
322 /* Enable touch detection. */
323 writel(LRADC_CTRL0_PLATE_MASK,
324 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
325 writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
326 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
328 msleep(LRADC_TS_SAMPLE_DELAY_MS);
330 reg = readl(lradc->base + LRADC_STATUS);
332 return reg & LRADC_STATUS_TOUCH_DETECT_RAW;
335 static int32_t mxs_lradc_ts_sample(struct mxs_lradc *lradc,
336 enum lradc_ts_plate plate, int change)
338 unsigned long delay, jiff;
339 uint32_t reg, ctrl0 = 0, chan = 0;
340 /* The touchscreen always uses CTRL4 slot #7. */
341 const uint8_t slot = 7;
345 * There are three correct configurations of the controller sampling
346 * the touchscreen, each of these configuration provides different
347 * information from the touchscreen.
349 * The following table describes the sampling configurations:
350 * +-------------+-------+-------+-------+
351 * | Wire \ Axis | X | Y | Z |
352 * +---------------------+-------+-------+
353 * | X+ (CH2) | HI | TS | TS |
354 * +-------------+-------+-------+-------+
355 * | X- (CH4) | LO | SH | HI |
356 * +-------------+-------+-------+-------+
357 * | Y+ (CH3) | SH | HI | HI |
358 * +-------------+-------+-------+-------+
359 * | Y- (CH5) | TS | LO | SH |
360 * +-------------+-------+-------+-------+
362 * HI ... strong '1' ; LO ... strong '0'
363 * SH ... sample here ; TS ... tri-state
365 * There are a few other ways of obtaining the Z coordinate
366 * (aka. pressure), but the one in the table seems to be the
371 ctrl0 = LRADC_CTRL0_XPPSW | LRADC_CTRL0_XNNSW;
375 ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_YNNSW;
378 case LRADC_SAMPLE_PRESSURE:
379 ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_XNNSW;
385 writel(LRADC_CTRL0_PLATE_MASK,
386 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
387 writel(ctrl0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
389 writel(LRADC_CTRL4_LRADCSELECT_MASK(slot),
390 lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
391 writel(chan << LRADC_CTRL4_LRADCSELECT_OFFSET(slot),
392 lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
395 writel(0xffffffff, lradc->base + LRADC_CH(slot) + STMP_OFFSET_REG_CLR);
396 writel(1 << slot, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
398 delay = jiffies + msecs_to_jiffies(LRADC_TS_SAMPLE_DELAY_MS);
401 reg = readl_relaxed(lradc->base + LRADC_CTRL1);
402 if (reg & LRADC_CTRL1_LRADC_IRQ(slot))
404 } while (time_before(jiff, delay));
406 writel(LRADC_CTRL1_LRADC_IRQ(slot),
407 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
409 if (time_after_eq(jiff, delay))
412 val = readl(lradc->base + LRADC_CH(slot));
413 val &= LRADC_CH_VALUE_MASK;
418 static int32_t mxs_lradc_ts_sample_filter(struct mxs_lradc *lradc,
419 enum lradc_ts_plate plate)
421 int32_t val, tot = 0;
424 val = mxs_lradc_ts_sample(lradc, plate, 1);
426 /* Delay a bit so the touchscreen is stable. */
429 for (i = 0; i < LRADC_TS_SAMPLE_AMOUNT; i++) {
430 val = mxs_lradc_ts_sample(lradc, plate, 0);
434 return tot / LRADC_TS_SAMPLE_AMOUNT;
437 static void mxs_lradc_ts_work(struct work_struct *ts_work)
439 struct mxs_lradc *lradc = container_of(ts_work,
440 struct mxs_lradc, ts_work);
441 int val_x, val_y, val_p;
444 while (mxs_lradc_ts_touched(lradc)) {
445 /* Disable touch detector so we can sample the touchscreen. */
446 writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
447 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
450 input_report_abs(lradc->ts_input, ABS_X, val_x);
451 input_report_abs(lradc->ts_input, ABS_Y, val_y);
452 input_report_abs(lradc->ts_input, ABS_PRESSURE, val_p);
453 input_report_key(lradc->ts_input, BTN_TOUCH, 1);
454 input_sync(lradc->ts_input);
459 val_x = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_X);
462 val_y = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_Y);
465 val_p = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_PRESSURE);
472 input_report_abs(lradc->ts_input, ABS_PRESSURE, 0);
473 input_report_key(lradc->ts_input, BTN_TOUCH, 0);
474 input_sync(lradc->ts_input);
476 /* Do not restart the TS IRQ if the driver is shutting down. */
477 if (lradc->stop_touchscreen)
480 /* Restart the touchscreen interrupts. */
481 writel(LRADC_CTRL1_TOUCH_DETECT_IRQ,
482 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
483 writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
484 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
487 static int mxs_lradc_ts_open(struct input_dev *dev)
489 struct mxs_lradc *lradc = input_get_drvdata(dev);
491 /* The touchscreen is starting. */
492 lradc->stop_touchscreen = false;
494 /* Enable the touch-detect circuitry. */
495 writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
496 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
498 /* Enable the touch-detect IRQ. */
499 writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
500 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
505 static void mxs_lradc_ts_close(struct input_dev *dev)
507 struct mxs_lradc *lradc = input_get_drvdata(dev);
509 /* Indicate the touchscreen is stopping. */
510 lradc->stop_touchscreen = true;
513 /* Wait until touchscreen thread finishes any possible remnants. */
514 cancel_work_sync(&lradc->ts_work);
516 /* Disable touchscreen touch-detect IRQ. */
517 writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
518 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
520 /* Power-down touchscreen touch-detect circuitry. */
521 writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
522 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
525 static int mxs_lradc_ts_register(struct mxs_lradc *lradc)
527 struct input_dev *input;
528 struct device *dev = lradc->dev;
531 if (!lradc->use_touchscreen)
534 input = input_allocate_device();
536 dev_err(dev, "Failed to allocate TS device!\n");
540 input->name = DRIVER_NAME;
541 input->id.bustype = BUS_HOST;
542 input->dev.parent = dev;
543 input->open = mxs_lradc_ts_open;
544 input->close = mxs_lradc_ts_close;
546 __set_bit(EV_ABS, input->evbit);
547 __set_bit(EV_KEY, input->evbit);
548 __set_bit(BTN_TOUCH, input->keybit);
549 input_set_abs_params(input, ABS_X, 0, LRADC_SINGLE_SAMPLE_MASK, 0, 0);
550 input_set_abs_params(input, ABS_Y, 0, LRADC_SINGLE_SAMPLE_MASK, 0, 0);
551 input_set_abs_params(input, ABS_PRESSURE, 0, LRADC_SINGLE_SAMPLE_MASK,
554 lradc->ts_input = input;
555 input_set_drvdata(input, lradc);
556 ret = input_register_device(input);
558 input_free_device(lradc->ts_input);
563 static void mxs_lradc_ts_unregister(struct mxs_lradc *lradc)
565 if (!lradc->use_touchscreen)
568 cancel_work_sync(&lradc->ts_work);
570 input_unregister_device(lradc->ts_input);
576 static irqreturn_t mxs_lradc_handle_irq(int irq, void *data)
578 struct iio_dev *iio = data;
579 struct mxs_lradc *lradc = iio_priv(iio);
580 unsigned long reg = readl(lradc->base + LRADC_CTRL1);
581 const uint32_t ts_irq_mask =
582 LRADC_CTRL1_TOUCH_DETECT_IRQ_EN |
583 LRADC_CTRL1_TOUCH_DETECT_IRQ;
585 if (!(reg & LRADC_CTRL1_LRADC_IRQ_MASK))
589 * Touchscreen IRQ handling code has priority and therefore
590 * is placed here. In case touchscreen IRQ arrives, disable
593 if (reg & LRADC_CTRL1_TOUCH_DETECT_IRQ) {
595 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
596 if (!lradc->stop_touchscreen)
597 schedule_work(&lradc->ts_work);
600 if (iio_buffer_enabled(iio))
601 iio_trigger_poll(iio->trig, iio_get_time_ns());
602 else if (reg & LRADC_CTRL1_LRADC_IRQ(0))
603 complete(&lradc->completion);
605 writel(reg & LRADC_CTRL1_LRADC_IRQ_MASK,
606 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
614 static irqreturn_t mxs_lradc_trigger_handler(int irq, void *p)
616 struct iio_poll_func *pf = p;
617 struct iio_dev *iio = pf->indio_dev;
618 struct mxs_lradc *lradc = iio_priv(iio);
619 const uint32_t chan_value = LRADC_CH_ACCUMULATE |
620 ((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
621 unsigned int i, j = 0;
623 for_each_set_bit(i, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) {
624 lradc->buffer[j] = readl(lradc->base + LRADC_CH(j));
625 writel(chan_value, lradc->base + LRADC_CH(j));
626 lradc->buffer[j] &= LRADC_CH_VALUE_MASK;
627 lradc->buffer[j] /= LRADC_DELAY_TIMER_LOOP;
631 iio_push_to_buffers_with_timestamp(iio, lradc->buffer, pf->timestamp);
633 iio_trigger_notify_done(iio->trig);
638 static int mxs_lradc_configure_trigger(struct iio_trigger *trig, bool state)
640 struct iio_dev *iio = iio_trigger_get_drvdata(trig);
641 struct mxs_lradc *lradc = iio_priv(iio);
642 const uint32_t st = state ? STMP_OFFSET_REG_SET : STMP_OFFSET_REG_CLR;
644 writel(LRADC_DELAY_KICK, lradc->base + LRADC_DELAY(0) + st);
649 static const struct iio_trigger_ops mxs_lradc_trigger_ops = {
650 .owner = THIS_MODULE,
651 .set_trigger_state = &mxs_lradc_configure_trigger,
654 static int mxs_lradc_trigger_init(struct iio_dev *iio)
657 struct iio_trigger *trig;
658 struct mxs_lradc *lradc = iio_priv(iio);
660 trig = iio_trigger_alloc("%s-dev%i", iio->name, iio->id);
664 trig->dev.parent = lradc->dev;
665 iio_trigger_set_drvdata(trig, iio);
666 trig->ops = &mxs_lradc_trigger_ops;
668 ret = iio_trigger_register(trig);
670 iio_trigger_free(trig);
679 static void mxs_lradc_trigger_remove(struct iio_dev *iio)
681 struct mxs_lradc *lradc = iio_priv(iio);
683 iio_trigger_unregister(lradc->trig);
684 iio_trigger_free(lradc->trig);
687 static int mxs_lradc_buffer_preenable(struct iio_dev *iio)
689 struct mxs_lradc *lradc = iio_priv(iio);
690 int ret = 0, chan, ofs = 0;
691 unsigned long enable = 0;
692 uint32_t ctrl4_set = 0;
693 uint32_t ctrl4_clr = 0;
694 uint32_t ctrl1_irq = 0;
695 const uint32_t chan_value = LRADC_CH_ACCUMULATE |
696 ((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
697 const int len = bitmap_weight(iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS);
703 * Lock the driver so raw access can not be done during buffered
704 * operation. This simplifies the code a lot.
706 ret = mutex_trylock(&lradc->lock);
710 lradc->buffer = kmalloc(len * sizeof(*lradc->buffer), GFP_KERNEL);
711 if (!lradc->buffer) {
716 ret = iio_sw_buffer_preenable(iio);
720 writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
721 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
722 writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
724 for_each_set_bit(chan, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) {
725 ctrl4_set |= chan << LRADC_CTRL4_LRADCSELECT_OFFSET(ofs);
726 ctrl4_clr |= LRADC_CTRL4_LRADCSELECT_MASK(ofs);
727 ctrl1_irq |= LRADC_CTRL1_LRADC_IRQ_EN(ofs);
728 writel(chan_value, lradc->base + LRADC_CH(ofs));
729 bitmap_set(&enable, ofs, 1);
733 writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
734 lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
736 writel(ctrl4_clr, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
737 writel(ctrl4_set, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
739 writel(ctrl1_irq, lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
741 writel(enable << LRADC_DELAY_TRIGGER_LRADCS_OFFSET,
742 lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_SET);
747 kfree(lradc->buffer);
749 mutex_unlock(&lradc->lock);
753 static int mxs_lradc_buffer_postdisable(struct iio_dev *iio)
755 struct mxs_lradc *lradc = iio_priv(iio);
757 writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
758 lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
760 writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
761 writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
762 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
764 kfree(lradc->buffer);
765 mutex_unlock(&lradc->lock);
770 static bool mxs_lradc_validate_scan_mask(struct iio_dev *iio,
771 const unsigned long *mask)
773 struct mxs_lradc *lradc = iio_priv(iio);
774 const int map_chans = bitmap_weight(mask, LRADC_MAX_TOTAL_CHANS);
776 unsigned long rsvd_mask = 0;
778 if (lradc->use_touchbutton)
779 rsvd_mask |= CHAN_MASK_TOUCHBUTTON;
780 if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_4WIRE)
781 rsvd_mask |= CHAN_MASK_TOUCHSCREEN_4WIRE;
782 if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE)
783 rsvd_mask |= CHAN_MASK_TOUCHSCREEN_5WIRE;
785 if (lradc->use_touchbutton)
787 if (lradc->use_touchscreen)
790 /* Test for attempts to map channels with special mode of operation. */
791 if (bitmap_intersects(mask, &rsvd_mask, LRADC_MAX_TOTAL_CHANS))
794 /* Test for attempts to map more channels then available slots. */
795 if (map_chans + rsvd_chans > LRADC_MAX_MAPPED_CHANS)
801 static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
802 .preenable = &mxs_lradc_buffer_preenable,
803 .postenable = &iio_triggered_buffer_postenable,
804 .predisable = &iio_triggered_buffer_predisable,
805 .postdisable = &mxs_lradc_buffer_postdisable,
806 .validate_scan_mask = &mxs_lradc_validate_scan_mask,
810 * Driver initialization
813 #define MXS_ADC_CHAN(idx, chan_type) { \
814 .type = (chan_type), \
816 .scan_index = (idx), \
817 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
821 .realbits = LRADC_RESOLUTION, \
826 static const struct iio_chan_spec mxs_lradc_chan_spec[] = {
827 MXS_ADC_CHAN(0, IIO_VOLTAGE),
828 MXS_ADC_CHAN(1, IIO_VOLTAGE),
829 MXS_ADC_CHAN(2, IIO_VOLTAGE),
830 MXS_ADC_CHAN(3, IIO_VOLTAGE),
831 MXS_ADC_CHAN(4, IIO_VOLTAGE),
832 MXS_ADC_CHAN(5, IIO_VOLTAGE),
833 MXS_ADC_CHAN(6, IIO_VOLTAGE),
834 MXS_ADC_CHAN(7, IIO_VOLTAGE), /* VBATT */
835 MXS_ADC_CHAN(8, IIO_TEMP), /* Temp sense 0 */
836 MXS_ADC_CHAN(9, IIO_TEMP), /* Temp sense 1 */
837 MXS_ADC_CHAN(10, IIO_VOLTAGE), /* VDDIO */
838 MXS_ADC_CHAN(11, IIO_VOLTAGE), /* VTH */
839 MXS_ADC_CHAN(12, IIO_VOLTAGE), /* VDDA */
840 MXS_ADC_CHAN(13, IIO_VOLTAGE), /* VDDD */
841 MXS_ADC_CHAN(14, IIO_VOLTAGE), /* VBG */
842 MXS_ADC_CHAN(15, IIO_VOLTAGE), /* VDD5V */
845 static int mxs_lradc_hw_init(struct mxs_lradc *lradc)
847 /* The ADC always uses DELAY CHANNEL 0. */
848 const uint32_t adc_cfg =
849 (1 << (LRADC_DELAY_TRIGGER_DELAYS_OFFSET + 0)) |
850 (LRADC_DELAY_TIMER_PER << LRADC_DELAY_DELAY_OFFSET);
852 int ret = stmp_reset_block(lradc->base);
856 /* Configure DELAY CHANNEL 0 for generic ADC sampling. */
857 writel(adc_cfg, lradc->base + LRADC_DELAY(0));
859 /* Disable remaining DELAY CHANNELs */
860 writel(0, lradc->base + LRADC_DELAY(1));
861 writel(0, lradc->base + LRADC_DELAY(2));
862 writel(0, lradc->base + LRADC_DELAY(3));
864 /* Configure the touchscreen type */
865 writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE,
866 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
868 if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE) {
869 writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE,
870 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
873 /* Start internal temperature sensing. */
874 writel(0, lradc->base + LRADC_CTRL2);
879 static void mxs_lradc_hw_stop(struct mxs_lradc *lradc)
883 writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
884 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
886 for (i = 0; i < LRADC_MAX_DELAY_CHANS; i++)
887 writel(0, lradc->base + LRADC_DELAY(i));
890 static const struct of_device_id mxs_lradc_dt_ids[] = {
891 { .compatible = "fsl,imx23-lradc", .data = (void *)IMX23_LRADC, },
892 { .compatible = "fsl,imx28-lradc", .data = (void *)IMX28_LRADC, },
895 MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
897 static int mxs_lradc_probe(struct platform_device *pdev)
899 const struct of_device_id *of_id =
900 of_match_device(mxs_lradc_dt_ids, &pdev->dev);
901 const struct mxs_lradc_of_config *of_cfg =
902 &mxs_lradc_of_config[(enum mxs_lradc_id)of_id->data];
903 struct device *dev = &pdev->dev;
904 struct device_node *node = dev->of_node;
905 struct mxs_lradc *lradc;
907 struct resource *iores;
908 uint32_t ts_wires = 0;
912 /* Allocate the IIO device. */
913 iio = devm_iio_device_alloc(dev, sizeof(*lradc));
915 dev_err(dev, "Failed to allocate IIO device\n");
919 lradc = iio_priv(iio);
921 /* Grab the memory area */
922 iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
923 lradc->dev = &pdev->dev;
924 lradc->base = devm_ioremap_resource(dev, iores);
925 if (IS_ERR(lradc->base))
926 return PTR_ERR(lradc->base);
928 lradc->clk = devm_clk_get(&pdev->dev, NULL);
929 if (IS_ERR(lradc->clk)) {
930 dev_err(dev, "Failed to get the delay unit clock\n");
931 return PTR_ERR(lradc->clk);
933 ret = clk_prepare_enable(lradc->clk);
935 dev_err(dev, "Failed to enable the delay unit clock\n");
939 INIT_WORK(&lradc->ts_work, mxs_lradc_ts_work);
941 /* Check if touchscreen is enabled in DT. */
942 ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
945 dev_info(dev, "Touchscreen not enabled.\n");
946 else if (ts_wires == 4)
947 lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_4WIRE;
948 else if (ts_wires == 5)
949 lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_5WIRE;
951 dev_warn(dev, "Unsupported number of touchscreen wires (%d)\n",
954 /* Grab all IRQ sources */
955 for (i = 0; i < of_cfg->irq_count; i++) {
956 lradc->irq[i] = platform_get_irq(pdev, i);
957 if (lradc->irq[i] < 0)
960 ret = devm_request_irq(dev, lradc->irq[i],
961 mxs_lradc_handle_irq, 0,
962 of_cfg->irq_name[i], iio);
967 platform_set_drvdata(pdev, iio);
969 init_completion(&lradc->completion);
970 mutex_init(&lradc->lock);
972 iio->name = pdev->name;
973 iio->dev.parent = &pdev->dev;
974 iio->info = &mxs_lradc_iio_info;
975 iio->modes = INDIO_DIRECT_MODE;
976 iio->channels = mxs_lradc_chan_spec;
977 iio->num_channels = ARRAY_SIZE(mxs_lradc_chan_spec);
978 iio->masklength = LRADC_MAX_TOTAL_CHANS;
980 ret = iio_triggered_buffer_setup(iio, &iio_pollfunc_store_time,
981 &mxs_lradc_trigger_handler,
982 &mxs_lradc_buffer_ops);
986 ret = mxs_lradc_trigger_init(iio);
990 /* Configure the hardware. */
991 ret = mxs_lradc_hw_init(lradc);
995 /* Register the touchscreen input device. */
996 ret = mxs_lradc_ts_register(lradc);
998 goto err_ts_register;
1000 /* Register IIO device. */
1001 ret = iio_device_register(iio);
1003 dev_err(dev, "Failed to register IIO device\n");
1010 mxs_lradc_ts_unregister(lradc);
1012 mxs_lradc_hw_stop(lradc);
1014 mxs_lradc_trigger_remove(iio);
1016 iio_triggered_buffer_cleanup(iio);
1020 static int mxs_lradc_remove(struct platform_device *pdev)
1022 struct iio_dev *iio = platform_get_drvdata(pdev);
1023 struct mxs_lradc *lradc = iio_priv(iio);
1025 iio_device_unregister(iio);
1026 mxs_lradc_ts_unregister(lradc);
1027 mxs_lradc_hw_stop(lradc);
1028 mxs_lradc_trigger_remove(iio);
1029 iio_triggered_buffer_cleanup(iio);
1031 clk_disable_unprepare(lradc->clk);
1035 static struct platform_driver mxs_lradc_driver = {
1037 .name = DRIVER_NAME,
1038 .owner = THIS_MODULE,
1039 .of_match_table = mxs_lradc_dt_ids,
1041 .probe = mxs_lradc_probe,
1042 .remove = mxs_lradc_remove,
1045 module_platform_driver(mxs_lradc_driver);
1047 MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
1048 MODULE_DESCRIPTION("Freescale i.MX28 LRADC driver");
1049 MODULE_LICENSE("GPL v2");
1050 MODULE_ALIAS("platform:" DRIVER_NAME);