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>
39 #include <linux/iio/iio.h>
40 #include <linux/iio/buffer.h>
41 #include <linux/iio/trigger.h>
42 #include <linux/iio/trigger_consumer.h>
43 #include <linux/iio/triggered_buffer.h>
45 #define DRIVER_NAME "mxs-lradc"
47 #define LRADC_MAX_DELAY_CHANS 4
48 #define LRADC_MAX_MAPPED_CHANS 8
49 #define LRADC_MAX_TOTAL_CHANS 16
51 #define LRADC_DELAY_TIMER_HZ 2000
54 * Make this runtime configurable if necessary. Currently, if the buffered mode
55 * is enabled, the LRADC takes LRADC_DELAY_TIMER_LOOP samples of data before
56 * triggering IRQ. The sampling happens every (LRADC_DELAY_TIMER_PER / 2000)
57 * seconds. The result is that the samples arrive every 500mS.
59 #define LRADC_DELAY_TIMER_PER 200
60 #define LRADC_DELAY_TIMER_LOOP 5
63 * Once the pen touches the touchscreen, the touchscreen switches from
64 * IRQ-driven mode to polling mode to prevent interrupt storm. The polling
65 * is realized by worker thread, which is called every 20 or so milliseconds.
66 * This gives the touchscreen enough fluence and does not strain the system
69 #define LRADC_TS_SAMPLE_DELAY_MS 5
72 * The LRADC reads the following amount of samples from each touchscreen
73 * channel and the driver then computes avarage of these.
75 #define LRADC_TS_SAMPLE_AMOUNT 4
82 static const char * const mx23_lradc_irq_names[] = {
83 "mxs-lradc-touchscreen",
94 static const char * const mx28_lradc_irq_names[] = {
95 "mxs-lradc-touchscreen",
100 "mxs-lradc-channel2",
101 "mxs-lradc-channel3",
102 "mxs-lradc-channel4",
103 "mxs-lradc-channel5",
104 "mxs-lradc-channel6",
105 "mxs-lradc-channel7",
110 struct mxs_lradc_of_config {
112 const char * const *irq_name;
115 static const struct mxs_lradc_of_config mxs_lradc_of_config[] = {
117 .irq_count = ARRAY_SIZE(mx23_lradc_irq_names),
118 .irq_name = mx23_lradc_irq_names,
121 .irq_count = ARRAY_SIZE(mx28_lradc_irq_names),
122 .irq_name = mx28_lradc_irq_names,
127 MXS_LRADC_TOUCHSCREEN_NONE = 0,
128 MXS_LRADC_TOUCHSCREEN_4WIRE,
129 MXS_LRADC_TOUCHSCREEN_5WIRE,
138 struct iio_trigger *trig;
142 struct completion completion;
145 * Touchscreen LRADC channels receives a private slot in the CTRL4
146 * register, the slot #7. Therefore only 7 slots instead of 8 in the
147 * CTRL4 register can be mapped to LRADC channels when using the
150 * Furthermore, certain LRADC channels are shared between touchscreen
151 * and/or touch-buttons and generic LRADC block. Therefore when using
152 * either of these, these channels are not available for the regular
153 * sampling. The shared channels are as follows:
155 * CH0 -- Touch button #0
156 * CH1 -- Touch button #1
157 * CH2 -- Touch screen XPUL
158 * CH3 -- Touch screen YPLL
159 * CH4 -- Touch screen XNUL
160 * CH5 -- Touch screen YNLR
161 * CH6 -- Touch screen WIPER (5-wire only)
163 * The bitfields below represents which parts of the LRADC block are
164 * switched into special mode of operation. These channels can not
165 * be sampled as regular LRADC channels. The driver will refuse any
166 * attempt to sample these channels.
168 #define CHAN_MASK_TOUCHBUTTON (0x3 << 0)
169 #define CHAN_MASK_TOUCHSCREEN_4WIRE (0xf << 2)
170 #define CHAN_MASK_TOUCHSCREEN_5WIRE (0x1f << 2)
171 enum mxs_lradc_ts use_touchscreen;
172 bool stop_touchscreen;
173 bool use_touchbutton;
175 struct input_dev *ts_input;
176 struct work_struct ts_work;
179 #define LRADC_CTRL0 0x00
180 #define LRADC_CTRL0_TOUCH_DETECT_ENABLE (1 << 23)
181 #define LRADC_CTRL0_TOUCH_SCREEN_TYPE (1 << 22)
182 #define LRADC_CTRL0_YNNSW /* YM */ (1 << 21)
183 #define LRADC_CTRL0_YPNSW /* YP */ (1 << 20)
184 #define LRADC_CTRL0_YPPSW /* YP */ (1 << 19)
185 #define LRADC_CTRL0_XNNSW /* XM */ (1 << 18)
186 #define LRADC_CTRL0_XNPSW /* XM */ (1 << 17)
187 #define LRADC_CTRL0_XPPSW /* XP */ (1 << 16)
188 #define LRADC_CTRL0_PLATE_MASK (0x3f << 16)
190 #define LRADC_CTRL1 0x10
191 #define LRADC_CTRL1_TOUCH_DETECT_IRQ_EN (1 << 24)
192 #define LRADC_CTRL1_LRADC_IRQ_EN(n) (1 << ((n) + 16))
193 #define LRADC_CTRL1_LRADC_IRQ_EN_MASK (0x1fff << 16)
194 #define LRADC_CTRL1_LRADC_IRQ_EN_OFFSET 16
195 #define LRADC_CTRL1_TOUCH_DETECT_IRQ (1 << 8)
196 #define LRADC_CTRL1_LRADC_IRQ(n) (1 << (n))
197 #define LRADC_CTRL1_LRADC_IRQ_MASK 0x1fff
198 #define LRADC_CTRL1_LRADC_IRQ_OFFSET 0
200 #define LRADC_CTRL2 0x20
201 #define LRADC_CTRL2_TEMPSENSE_PWD (1 << 15)
203 #define LRADC_STATUS 0x40
204 #define LRADC_STATUS_TOUCH_DETECT_RAW (1 << 0)
206 #define LRADC_CH(n) (0x50 + (0x10 * (n)))
207 #define LRADC_CH_ACCUMULATE (1 << 29)
208 #define LRADC_CH_NUM_SAMPLES_MASK (0x1f << 24)
209 #define LRADC_CH_NUM_SAMPLES_OFFSET 24
210 #define LRADC_CH_VALUE_MASK 0x3ffff
211 #define LRADC_CH_VALUE_OFFSET 0
213 #define LRADC_DELAY(n) (0xd0 + (0x10 * (n)))
214 #define LRADC_DELAY_TRIGGER_LRADCS_MASK (0xff << 24)
215 #define LRADC_DELAY_TRIGGER_LRADCS_OFFSET 24
216 #define LRADC_DELAY_KICK (1 << 20)
217 #define LRADC_DELAY_TRIGGER_DELAYS_MASK (0xf << 16)
218 #define LRADC_DELAY_TRIGGER_DELAYS_OFFSET 16
219 #define LRADC_DELAY_LOOP_COUNT_MASK (0x1f << 11)
220 #define LRADC_DELAY_LOOP_COUNT_OFFSET 11
221 #define LRADC_DELAY_DELAY_MASK 0x7ff
222 #define LRADC_DELAY_DELAY_OFFSET 0
224 #define LRADC_CTRL4 0x140
225 #define LRADC_CTRL4_LRADCSELECT_MASK(n) (0xf << ((n) * 4))
226 #define LRADC_CTRL4_LRADCSELECT_OFFSET(n) ((n) * 4)
231 static int mxs_lradc_read_raw(struct iio_dev *iio_dev,
232 const struct iio_chan_spec *chan,
233 int *val, int *val2, long m)
235 struct mxs_lradc *lradc = iio_priv(iio_dev);
238 if (m != IIO_CHAN_INFO_RAW)
241 /* Check for invalid channel */
242 if (chan->channel > LRADC_MAX_TOTAL_CHANS)
246 * See if there is no buffered operation in progess. If there is, simply
247 * bail out. This can be improved to support both buffered and raw IO at
248 * the same time, yet the code becomes horribly complicated. Therefore I
249 * applied KISS principle here.
251 ret = mutex_trylock(&lradc->lock);
255 INIT_COMPLETION(lradc->completion);
258 * No buffered operation in progress, map the channel and trigger it.
259 * Virtual channel 0 is always used here as the others are always not
260 * used if doing raw sampling.
262 writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
263 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
264 writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
266 /* Clean the slot's previous content, then set new one. */
267 writel(LRADC_CTRL4_LRADCSELECT_MASK(0),
268 lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
269 writel(chan->channel, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
271 writel(0, lradc->base + LRADC_CH(0));
273 /* Enable the IRQ and start sampling the channel. */
274 writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
275 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
276 writel(1 << 0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
278 /* Wait for completion on the channel, 1 second max. */
279 ret = wait_for_completion_killable_timeout(&lradc->completion, HZ);
286 *val = readl(lradc->base + LRADC_CH(0)) & LRADC_CH_VALUE_MASK;
290 writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
291 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
293 mutex_unlock(&lradc->lock);
298 static const struct iio_info mxs_lradc_iio_info = {
299 .driver_module = THIS_MODULE,
300 .read_raw = mxs_lradc_read_raw,
304 * Touchscreen handling
306 enum lradc_ts_plate {
309 LRADC_SAMPLE_PRESSURE,
312 static int mxs_lradc_ts_touched(struct mxs_lradc *lradc)
316 /* Enable touch detection. */
317 writel(LRADC_CTRL0_PLATE_MASK,
318 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
319 writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
320 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
322 msleep(LRADC_TS_SAMPLE_DELAY_MS);
324 reg = readl(lradc->base + LRADC_STATUS);
326 return reg & LRADC_STATUS_TOUCH_DETECT_RAW;
329 static int32_t mxs_lradc_ts_sample(struct mxs_lradc *lradc,
330 enum lradc_ts_plate plate, int change)
332 unsigned long delay, jiff;
333 uint32_t reg, ctrl0 = 0, chan = 0;
334 /* The touchscreen always uses CTRL4 slot #7. */
335 const uint8_t slot = 7;
339 * There are three correct configurations of the controller sampling
340 * the touchscreen, each of these configuration provides different
341 * information from the touchscreen.
343 * The following table describes the sampling configurations:
344 * +-------------+-------+-------+-------+
345 * | Wire \ Axis | X | Y | Z |
346 * +---------------------+-------+-------+
347 * | X+ (CH2) | HI | TS | TS |
348 * +-------------+-------+-------+-------+
349 * | X- (CH4) | LO | SH | HI |
350 * +-------------+-------+-------+-------+
351 * | Y+ (CH3) | SH | HI | HI |
352 * +-------------+-------+-------+-------+
353 * | Y- (CH5) | TS | LO | SH |
354 * +-------------+-------+-------+-------+
356 * HI ... strong '1' ; LO ... strong '0'
357 * SH ... sample here ; TS ... tri-state
359 * There are a few other ways of obtaining the Z coordinate
360 * (aka. pressure), but the one in the table seems to be the
365 ctrl0 = LRADC_CTRL0_XPPSW | LRADC_CTRL0_XNNSW;
369 ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_YNNSW;
372 case LRADC_SAMPLE_PRESSURE:
373 ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_XNNSW;
379 writel(LRADC_CTRL0_PLATE_MASK,
380 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
381 writel(ctrl0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
383 writel(LRADC_CTRL4_LRADCSELECT_MASK(slot),
384 lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
385 writel(chan << LRADC_CTRL4_LRADCSELECT_OFFSET(slot),
386 lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
389 writel(0xffffffff, lradc->base + LRADC_CH(slot) + STMP_OFFSET_REG_CLR);
390 writel(1 << slot, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
392 delay = jiffies + msecs_to_jiffies(LRADC_TS_SAMPLE_DELAY_MS);
395 reg = readl_relaxed(lradc->base + LRADC_CTRL1);
396 if (reg & LRADC_CTRL1_LRADC_IRQ(slot))
398 } while (time_before(jiff, delay));
400 writel(LRADC_CTRL1_LRADC_IRQ(slot),
401 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
403 if (time_after_eq(jiff, delay))
406 val = readl(lradc->base + LRADC_CH(slot));
407 val &= LRADC_CH_VALUE_MASK;
412 static int32_t mxs_lradc_ts_sample_filter(struct mxs_lradc *lradc,
413 enum lradc_ts_plate plate)
415 int32_t val, tot = 0;
418 val = mxs_lradc_ts_sample(lradc, plate, 1);
420 /* Delay a bit so the touchscreen is stable. */
423 for (i = 0; i < LRADC_TS_SAMPLE_AMOUNT; i++) {
424 val = mxs_lradc_ts_sample(lradc, plate, 0);
428 return tot / LRADC_TS_SAMPLE_AMOUNT;
431 static void mxs_lradc_ts_work(struct work_struct *ts_work)
433 struct mxs_lradc *lradc = container_of(ts_work,
434 struct mxs_lradc, ts_work);
435 int val_x, val_y, val_p;
438 while (mxs_lradc_ts_touched(lradc)) {
439 /* Disable touch detector so we can sample the touchscreen. */
440 writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
441 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
444 input_report_abs(lradc->ts_input, ABS_X, val_x);
445 input_report_abs(lradc->ts_input, ABS_Y, val_y);
446 input_report_abs(lradc->ts_input, ABS_PRESSURE, val_p);
447 input_report_key(lradc->ts_input, BTN_TOUCH, 1);
448 input_sync(lradc->ts_input);
453 val_x = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_X);
456 val_y = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_Y);
459 val_p = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_PRESSURE);
466 input_report_abs(lradc->ts_input, ABS_PRESSURE, 0);
467 input_report_key(lradc->ts_input, BTN_TOUCH, 0);
468 input_sync(lradc->ts_input);
470 /* Do not restart the TS IRQ if the driver is shutting down. */
471 if (lradc->stop_touchscreen)
474 /* Restart the touchscreen interrupts. */
475 writel(LRADC_CTRL1_TOUCH_DETECT_IRQ,
476 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
477 writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
478 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
481 static int mxs_lradc_ts_open(struct input_dev *dev)
483 struct mxs_lradc *lradc = input_get_drvdata(dev);
485 /* The touchscreen is starting. */
486 lradc->stop_touchscreen = false;
488 /* Enable the touch-detect circuitry. */
489 writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
490 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
492 /* Enable the touch-detect IRQ. */
493 writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
494 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
499 static void mxs_lradc_ts_close(struct input_dev *dev)
501 struct mxs_lradc *lradc = input_get_drvdata(dev);
503 /* Indicate the touchscreen is stopping. */
504 lradc->stop_touchscreen = true;
507 /* Wait until touchscreen thread finishes any possible remnants. */
508 cancel_work_sync(&lradc->ts_work);
510 /* Disable touchscreen touch-detect IRQ. */
511 writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
512 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
514 /* Power-down touchscreen touch-detect circuitry. */
515 writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
516 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
519 static int mxs_lradc_ts_register(struct mxs_lradc *lradc)
521 struct input_dev *input;
522 struct device *dev = lradc->dev;
525 if (!lradc->use_touchscreen)
528 input = input_allocate_device();
530 dev_err(dev, "Failed to allocate TS device!\n");
534 input->name = DRIVER_NAME;
535 input->id.bustype = BUS_HOST;
536 input->dev.parent = dev;
537 input->open = mxs_lradc_ts_open;
538 input->close = mxs_lradc_ts_close;
540 __set_bit(EV_ABS, input->evbit);
541 __set_bit(EV_KEY, input->evbit);
542 __set_bit(BTN_TOUCH, input->keybit);
543 input_set_abs_params(input, ABS_X, 0, LRADC_CH_VALUE_MASK, 0, 0);
544 input_set_abs_params(input, ABS_Y, 0, LRADC_CH_VALUE_MASK, 0, 0);
545 input_set_abs_params(input, ABS_PRESSURE, 0, LRADC_CH_VALUE_MASK, 0, 0);
547 lradc->ts_input = input;
548 input_set_drvdata(input, lradc);
549 ret = input_register_device(input);
551 input_free_device(lradc->ts_input);
556 static void mxs_lradc_ts_unregister(struct mxs_lradc *lradc)
558 if (!lradc->use_touchscreen)
561 cancel_work_sync(&lradc->ts_work);
563 input_unregister_device(lradc->ts_input);
569 static irqreturn_t mxs_lradc_handle_irq(int irq, void *data)
571 struct iio_dev *iio = data;
572 struct mxs_lradc *lradc = iio_priv(iio);
573 unsigned long reg = readl(lradc->base + LRADC_CTRL1);
574 const uint32_t ts_irq_mask =
575 LRADC_CTRL1_TOUCH_DETECT_IRQ_EN |
576 LRADC_CTRL1_TOUCH_DETECT_IRQ;
578 if (!(reg & LRADC_CTRL1_LRADC_IRQ_MASK))
582 * Touchscreen IRQ handling code has priority and therefore
583 * is placed here. In case touchscreen IRQ arrives, disable
586 if (reg & LRADC_CTRL1_TOUCH_DETECT_IRQ) {
588 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
589 if (!lradc->stop_touchscreen)
590 schedule_work(&lradc->ts_work);
593 if (iio_buffer_enabled(iio))
594 iio_trigger_poll(iio->trig, iio_get_time_ns());
595 else if (reg & LRADC_CTRL1_LRADC_IRQ(0))
596 complete(&lradc->completion);
598 writel(reg & LRADC_CTRL1_LRADC_IRQ_MASK,
599 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
607 static irqreturn_t mxs_lradc_trigger_handler(int irq, void *p)
609 struct iio_poll_func *pf = p;
610 struct iio_dev *iio = pf->indio_dev;
611 struct mxs_lradc *lradc = iio_priv(iio);
612 const uint32_t chan_value = LRADC_CH_ACCUMULATE |
613 ((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
614 unsigned int i, j = 0;
616 for_each_set_bit(i, iio->active_scan_mask, iio->masklength) {
617 lradc->buffer[j] = readl(lradc->base + LRADC_CH(j));
618 writel(chan_value, lradc->base + LRADC_CH(j));
619 lradc->buffer[j] &= LRADC_CH_VALUE_MASK;
620 lradc->buffer[j] /= LRADC_DELAY_TIMER_LOOP;
624 if (iio->scan_timestamp) {
625 s64 *timestamp = (s64 *)((u8 *)lradc->buffer +
626 ALIGN(j, sizeof(s64)));
627 *timestamp = pf->timestamp;
630 iio_push_to_buffers(iio, (u8 *)lradc->buffer);
632 iio_trigger_notify_done(iio->trig);
637 static int mxs_lradc_configure_trigger(struct iio_trigger *trig, bool state)
639 struct iio_dev *iio = iio_trigger_get_drvdata(trig);
640 struct mxs_lradc *lradc = iio_priv(iio);
641 const uint32_t st = state ? STMP_OFFSET_REG_SET : STMP_OFFSET_REG_CLR;
643 writel(LRADC_DELAY_KICK, lradc->base + LRADC_DELAY(0) + st);
648 static const struct iio_trigger_ops mxs_lradc_trigger_ops = {
649 .owner = THIS_MODULE,
650 .set_trigger_state = &mxs_lradc_configure_trigger,
653 static int mxs_lradc_trigger_init(struct iio_dev *iio)
656 struct iio_trigger *trig;
657 struct mxs_lradc *lradc = iio_priv(iio);
659 trig = iio_trigger_alloc("%s-dev%i", iio->name, iio->id);
663 trig->dev.parent = lradc->dev;
664 iio_trigger_set_drvdata(trig, iio);
665 trig->ops = &mxs_lradc_trigger_ops;
667 ret = iio_trigger_register(trig);
669 iio_trigger_free(trig);
678 static void mxs_lradc_trigger_remove(struct iio_dev *iio)
680 struct mxs_lradc *lradc = iio_priv(iio);
682 iio_trigger_unregister(lradc->trig);
683 iio_trigger_free(lradc->trig);
686 static int mxs_lradc_buffer_preenable(struct iio_dev *iio)
688 struct mxs_lradc *lradc = iio_priv(iio);
689 int ret = 0, chan, ofs = 0;
690 unsigned long enable = 0;
691 uint32_t ctrl4_set = 0;
692 uint32_t ctrl4_clr = 0;
693 uint32_t ctrl1_irq = 0;
694 const uint32_t chan_value = LRADC_CH_ACCUMULATE |
695 ((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
696 const int len = bitmap_weight(iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS);
702 * Lock the driver so raw access can not be done during buffered
703 * operation. This simplifies the code a lot.
705 ret = mutex_trylock(&lradc->lock);
709 lradc->buffer = kmalloc(len * sizeof(*lradc->buffer), GFP_KERNEL);
710 if (!lradc->buffer) {
715 ret = iio_sw_buffer_preenable(iio);
719 writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
720 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
721 writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
723 for_each_set_bit(chan, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) {
724 ctrl4_set |= chan << LRADC_CTRL4_LRADCSELECT_OFFSET(ofs);
725 ctrl4_clr |= LRADC_CTRL4_LRADCSELECT_MASK(ofs);
726 ctrl1_irq |= LRADC_CTRL1_LRADC_IRQ_EN(ofs);
727 writel(chan_value, lradc->base + LRADC_CH(ofs));
728 bitmap_set(&enable, ofs, 1);
732 writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
733 lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
735 writel(ctrl4_clr, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
736 writel(ctrl4_set, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
738 writel(ctrl1_irq, lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
740 writel(enable << LRADC_DELAY_TRIGGER_LRADCS_OFFSET,
741 lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_SET);
746 kfree(lradc->buffer);
748 mutex_unlock(&lradc->lock);
752 static int mxs_lradc_buffer_postdisable(struct iio_dev *iio)
754 struct mxs_lradc *lradc = iio_priv(iio);
756 writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
757 lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
759 writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
760 writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
761 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
763 kfree(lradc->buffer);
764 mutex_unlock(&lradc->lock);
769 static bool mxs_lradc_validate_scan_mask(struct iio_dev *iio,
770 const unsigned long *mask)
772 struct mxs_lradc *lradc = iio_priv(iio);
773 const int len = iio->masklength;
774 const int map_chans = bitmap_weight(mask, len);
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, len))
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), \
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 void 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 stmp_reset_block(lradc->base);
854 /* Configure DELAY CHANNEL 0 for generic ADC sampling. */
855 writel(adc_cfg, lradc->base + LRADC_DELAY(0));
857 /* Disable remaining DELAY CHANNELs */
858 writel(0, lradc->base + LRADC_DELAY(1));
859 writel(0, lradc->base + LRADC_DELAY(2));
860 writel(0, lradc->base + LRADC_DELAY(3));
862 /* Configure the touchscreen type */
863 writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE,
864 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
866 if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE) {
867 writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE,
868 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
871 /* Start internal temperature sensing. */
872 writel(0, lradc->base + LRADC_CTRL2);
875 static void mxs_lradc_hw_stop(struct mxs_lradc *lradc)
879 writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
880 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
882 for (i = 0; i < LRADC_MAX_DELAY_CHANS; i++)
883 writel(0, lradc->base + LRADC_DELAY(i));
886 static const struct of_device_id mxs_lradc_dt_ids[] = {
887 { .compatible = "fsl,imx23-lradc", .data = (void *)IMX23_LRADC, },
888 { .compatible = "fsl,imx28-lradc", .data = (void *)IMX28_LRADC, },
891 MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
893 static int mxs_lradc_probe(struct platform_device *pdev)
895 const struct of_device_id *of_id =
896 of_match_device(mxs_lradc_dt_ids, &pdev->dev);
897 const struct mxs_lradc_of_config *of_cfg =
898 &mxs_lradc_of_config[(enum mxs_lradc_id)of_id->data];
899 struct device *dev = &pdev->dev;
900 struct device_node *node = dev->of_node;
901 struct mxs_lradc *lradc;
903 struct resource *iores;
904 uint32_t ts_wires = 0;
908 /* Allocate the IIO device. */
909 iio = iio_device_alloc(sizeof(*lradc));
911 dev_err(dev, "Failed to allocate IIO device\n");
915 lradc = iio_priv(iio);
917 /* Grab the memory area */
918 iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
919 lradc->dev = &pdev->dev;
920 lradc->base = devm_ioremap_resource(dev, iores);
921 if (IS_ERR(lradc->base)) {
922 ret = PTR_ERR(lradc->base);
926 INIT_WORK(&lradc->ts_work, mxs_lradc_ts_work);
928 /* Check if touchscreen is enabled in DT. */
929 ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
932 dev_info(dev, "Touchscreen not enabled.\n");
933 else if (ts_wires == 4)
934 lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_4WIRE;
935 else if (ts_wires == 5)
936 lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_5WIRE;
938 dev_warn(dev, "Unsupported number of touchscreen wires (%d)\n",
941 /* Grab all IRQ sources */
942 for (i = 0; i < of_cfg->irq_count; i++) {
943 lradc->irq[i] = platform_get_irq(pdev, i);
944 if (lradc->irq[i] < 0) {
949 ret = devm_request_irq(dev, lradc->irq[i],
950 mxs_lradc_handle_irq, 0,
951 of_cfg->irq_name[i], iio);
956 platform_set_drvdata(pdev, iio);
958 init_completion(&lradc->completion);
959 mutex_init(&lradc->lock);
961 iio->name = pdev->name;
962 iio->dev.parent = &pdev->dev;
963 iio->info = &mxs_lradc_iio_info;
964 iio->modes = INDIO_DIRECT_MODE;
965 iio->channels = mxs_lradc_chan_spec;
966 iio->num_channels = ARRAY_SIZE(mxs_lradc_chan_spec);
968 ret = iio_triggered_buffer_setup(iio, &iio_pollfunc_store_time,
969 &mxs_lradc_trigger_handler,
970 &mxs_lradc_buffer_ops);
974 ret = mxs_lradc_trigger_init(iio);
978 /* Configure the hardware. */
979 mxs_lradc_hw_init(lradc);
981 /* Register the touchscreen input device. */
982 ret = mxs_lradc_ts_register(lradc);
986 /* Register IIO device. */
987 ret = iio_device_register(iio);
989 dev_err(dev, "Failed to register IIO device\n");
996 mxs_lradc_ts_unregister(lradc);
998 mxs_lradc_trigger_remove(iio);
1000 iio_triggered_buffer_cleanup(iio);
1002 iio_device_free(iio);
1006 static int mxs_lradc_remove(struct platform_device *pdev)
1008 struct iio_dev *iio = platform_get_drvdata(pdev);
1009 struct mxs_lradc *lradc = iio_priv(iio);
1011 mxs_lradc_ts_unregister(lradc);
1013 mxs_lradc_hw_stop(lradc);
1015 iio_device_unregister(iio);
1016 iio_triggered_buffer_cleanup(iio);
1017 mxs_lradc_trigger_remove(iio);
1018 iio_device_free(iio);
1023 static struct platform_driver mxs_lradc_driver = {
1025 .name = DRIVER_NAME,
1026 .owner = THIS_MODULE,
1027 .of_match_table = mxs_lradc_dt_ids,
1029 .probe = mxs_lradc_probe,
1030 .remove = mxs_lradc_remove,
1033 module_platform_driver(mxs_lradc_driver);
1035 MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
1036 MODULE_DESCRIPTION("Freescale i.MX28 LRADC driver");
1037 MODULE_LICENSE("GPL v2");