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);
239 if (m != IIO_CHAN_INFO_RAW)
242 /* Check for invalid channel */
243 if (chan->channel > LRADC_MAX_TOTAL_CHANS)
246 /* Validate the channel if it doesn't intersect with reserved chans. */
247 bitmap_set(&mask, chan->channel, 1);
248 ret = iio_validate_scan_mask_onehot(iio_dev, &mask);
253 * See if there is no buffered operation in progess. If there is, simply
254 * bail out. This can be improved to support both buffered and raw IO at
255 * the same time, yet the code becomes horribly complicated. Therefore I
256 * applied KISS principle here.
258 ret = mutex_trylock(&lradc->lock);
262 INIT_COMPLETION(lradc->completion);
265 * No buffered operation in progress, map the channel and trigger it.
266 * Virtual channel 0 is always used here as the others are always not
267 * used if doing raw sampling.
269 writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
270 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
271 writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
273 /* Clean the slot's previous content, then set new one. */
274 writel(LRADC_CTRL4_LRADCSELECT_MASK(0),
275 lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
276 writel(chan->channel, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
278 writel(0, lradc->base + LRADC_CH(0));
280 /* Enable the IRQ and start sampling the channel. */
281 writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
282 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
283 writel(1 << 0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
285 /* Wait for completion on the channel, 1 second max. */
286 ret = wait_for_completion_killable_timeout(&lradc->completion, HZ);
293 *val = readl(lradc->base + LRADC_CH(0)) & LRADC_CH_VALUE_MASK;
297 writel(LRADC_CTRL1_LRADC_IRQ_EN(0),
298 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
300 mutex_unlock(&lradc->lock);
305 static const struct iio_info mxs_lradc_iio_info = {
306 .driver_module = THIS_MODULE,
307 .read_raw = mxs_lradc_read_raw,
311 * Touchscreen handling
313 enum lradc_ts_plate {
316 LRADC_SAMPLE_PRESSURE,
319 static int mxs_lradc_ts_touched(struct mxs_lradc *lradc)
323 /* Enable touch detection. */
324 writel(LRADC_CTRL0_PLATE_MASK,
325 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
326 writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
327 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
329 msleep(LRADC_TS_SAMPLE_DELAY_MS);
331 reg = readl(lradc->base + LRADC_STATUS);
333 return reg & LRADC_STATUS_TOUCH_DETECT_RAW;
336 static int32_t mxs_lradc_ts_sample(struct mxs_lradc *lradc,
337 enum lradc_ts_plate plate, int change)
339 unsigned long delay, jiff;
340 uint32_t reg, ctrl0 = 0, chan = 0;
341 /* The touchscreen always uses CTRL4 slot #7. */
342 const uint8_t slot = 7;
346 * There are three correct configurations of the controller sampling
347 * the touchscreen, each of these configuration provides different
348 * information from the touchscreen.
350 * The following table describes the sampling configurations:
351 * +-------------+-------+-------+-------+
352 * | Wire \ Axis | X | Y | Z |
353 * +---------------------+-------+-------+
354 * | X+ (CH2) | HI | TS | TS |
355 * +-------------+-------+-------+-------+
356 * | X- (CH4) | LO | SH | HI |
357 * +-------------+-------+-------+-------+
358 * | Y+ (CH3) | SH | HI | HI |
359 * +-------------+-------+-------+-------+
360 * | Y- (CH5) | TS | LO | SH |
361 * +-------------+-------+-------+-------+
363 * HI ... strong '1' ; LO ... strong '0'
364 * SH ... sample here ; TS ... tri-state
366 * There are a few other ways of obtaining the Z coordinate
367 * (aka. pressure), but the one in the table seems to be the
372 ctrl0 = LRADC_CTRL0_XPPSW | LRADC_CTRL0_XNNSW;
376 ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_YNNSW;
379 case LRADC_SAMPLE_PRESSURE:
380 ctrl0 = LRADC_CTRL0_YPPSW | LRADC_CTRL0_XNNSW;
386 writel(LRADC_CTRL0_PLATE_MASK,
387 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
388 writel(ctrl0, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
390 writel(LRADC_CTRL4_LRADCSELECT_MASK(slot),
391 lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
392 writel(chan << LRADC_CTRL4_LRADCSELECT_OFFSET(slot),
393 lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
396 writel(0xffffffff, lradc->base + LRADC_CH(slot) + STMP_OFFSET_REG_CLR);
397 writel(1 << slot, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
399 delay = jiffies + msecs_to_jiffies(LRADC_TS_SAMPLE_DELAY_MS);
402 reg = readl_relaxed(lradc->base + LRADC_CTRL1);
403 if (reg & LRADC_CTRL1_LRADC_IRQ(slot))
405 } while (time_before(jiff, delay));
407 writel(LRADC_CTRL1_LRADC_IRQ(slot),
408 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
410 if (time_after_eq(jiff, delay))
413 val = readl(lradc->base + LRADC_CH(slot));
414 val &= LRADC_CH_VALUE_MASK;
419 static int32_t mxs_lradc_ts_sample_filter(struct mxs_lradc *lradc,
420 enum lradc_ts_plate plate)
422 int32_t val, tot = 0;
425 val = mxs_lradc_ts_sample(lradc, plate, 1);
427 /* Delay a bit so the touchscreen is stable. */
430 for (i = 0; i < LRADC_TS_SAMPLE_AMOUNT; i++) {
431 val = mxs_lradc_ts_sample(lradc, plate, 0);
435 return tot / LRADC_TS_SAMPLE_AMOUNT;
438 static void mxs_lradc_ts_work(struct work_struct *ts_work)
440 struct mxs_lradc *lradc = container_of(ts_work,
441 struct mxs_lradc, ts_work);
442 int val_x, val_y, val_p;
445 while (mxs_lradc_ts_touched(lradc)) {
446 /* Disable touch detector so we can sample the touchscreen. */
447 writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
448 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
451 input_report_abs(lradc->ts_input, ABS_X, val_x);
452 input_report_abs(lradc->ts_input, ABS_Y, val_y);
453 input_report_abs(lradc->ts_input, ABS_PRESSURE, val_p);
454 input_report_key(lradc->ts_input, BTN_TOUCH, 1);
455 input_sync(lradc->ts_input);
460 val_x = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_X);
463 val_y = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_Y);
466 val_p = mxs_lradc_ts_sample_filter(lradc, LRADC_SAMPLE_PRESSURE);
473 input_report_abs(lradc->ts_input, ABS_PRESSURE, 0);
474 input_report_key(lradc->ts_input, BTN_TOUCH, 0);
475 input_sync(lradc->ts_input);
477 /* Do not restart the TS IRQ if the driver is shutting down. */
478 if (lradc->stop_touchscreen)
481 /* Restart the touchscreen interrupts. */
482 writel(LRADC_CTRL1_TOUCH_DETECT_IRQ,
483 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
484 writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
485 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
488 static int mxs_lradc_ts_open(struct input_dev *dev)
490 struct mxs_lradc *lradc = input_get_drvdata(dev);
492 /* The touchscreen is starting. */
493 lradc->stop_touchscreen = false;
495 /* Enable the touch-detect circuitry. */
496 writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
497 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
499 /* Enable the touch-detect IRQ. */
500 writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
501 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
506 static void mxs_lradc_ts_close(struct input_dev *dev)
508 struct mxs_lradc *lradc = input_get_drvdata(dev);
510 /* Indicate the touchscreen is stopping. */
511 lradc->stop_touchscreen = true;
514 /* Wait until touchscreen thread finishes any possible remnants. */
515 cancel_work_sync(&lradc->ts_work);
517 /* Disable touchscreen touch-detect IRQ. */
518 writel(LRADC_CTRL1_TOUCH_DETECT_IRQ_EN,
519 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
521 /* Power-down touchscreen touch-detect circuitry. */
522 writel(LRADC_CTRL0_TOUCH_DETECT_ENABLE,
523 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
526 static int mxs_lradc_ts_register(struct mxs_lradc *lradc)
528 struct input_dev *input;
529 struct device *dev = lradc->dev;
532 if (!lradc->use_touchscreen)
535 input = input_allocate_device();
537 dev_err(dev, "Failed to allocate TS device!\n");
541 input->name = DRIVER_NAME;
542 input->id.bustype = BUS_HOST;
543 input->dev.parent = dev;
544 input->open = mxs_lradc_ts_open;
545 input->close = mxs_lradc_ts_close;
547 __set_bit(EV_ABS, input->evbit);
548 __set_bit(EV_KEY, input->evbit);
549 __set_bit(BTN_TOUCH, input->keybit);
550 input_set_abs_params(input, ABS_X, 0, LRADC_CH_VALUE_MASK, 0, 0);
551 input_set_abs_params(input, ABS_Y, 0, LRADC_CH_VALUE_MASK, 0, 0);
552 input_set_abs_params(input, ABS_PRESSURE, 0, LRADC_CH_VALUE_MASK, 0, 0);
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, iio->masklength) {
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 if (iio->scan_timestamp) {
632 s64 *timestamp = (s64 *)((u8 *)lradc->buffer +
633 ALIGN(j, sizeof(s64)));
634 *timestamp = pf->timestamp;
637 iio_push_to_buffers(iio, (u8 *)lradc->buffer);
639 iio_trigger_notify_done(iio->trig);
644 static int mxs_lradc_configure_trigger(struct iio_trigger *trig, bool state)
646 struct iio_dev *iio = iio_trigger_get_drvdata(trig);
647 struct mxs_lradc *lradc = iio_priv(iio);
648 const uint32_t st = state ? STMP_OFFSET_REG_SET : STMP_OFFSET_REG_CLR;
650 writel(LRADC_DELAY_KICK, lradc->base + LRADC_DELAY(0) + st);
655 static const struct iio_trigger_ops mxs_lradc_trigger_ops = {
656 .owner = THIS_MODULE,
657 .set_trigger_state = &mxs_lradc_configure_trigger,
660 static int mxs_lradc_trigger_init(struct iio_dev *iio)
663 struct iio_trigger *trig;
665 trig = iio_trigger_alloc("%s-dev%i", iio->name, iio->id);
669 trig->dev.parent = iio->dev.parent;
670 iio_trigger_set_drvdata(trig, iio);
671 trig->ops = &mxs_lradc_trigger_ops;
673 ret = iio_trigger_register(trig);
675 iio_trigger_free(trig);
684 static void mxs_lradc_trigger_remove(struct iio_dev *iio)
686 iio_trigger_unregister(iio->trig);
687 iio_trigger_free(iio->trig);
690 static int mxs_lradc_buffer_preenable(struct iio_dev *iio)
692 struct mxs_lradc *lradc = iio_priv(iio);
693 int ret = 0, chan, ofs = 0;
694 unsigned long enable = 0;
695 uint32_t ctrl4_set = 0;
696 uint32_t ctrl4_clr = 0;
697 uint32_t ctrl1_irq = 0;
698 const uint32_t chan_value = LRADC_CH_ACCUMULATE |
699 ((LRADC_DELAY_TIMER_LOOP - 1) << LRADC_CH_NUM_SAMPLES_OFFSET);
700 const int len = bitmap_weight(iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS);
706 * Lock the driver so raw access can not be done during buffered
707 * operation. This simplifies the code a lot.
709 ret = mutex_trylock(&lradc->lock);
713 lradc->buffer = kmalloc(len * sizeof(*lradc->buffer), GFP_KERNEL);
714 if (!lradc->buffer) {
719 ret = iio_sw_buffer_preenable(iio);
723 writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
724 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
725 writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
727 for_each_set_bit(chan, iio->active_scan_mask, LRADC_MAX_TOTAL_CHANS) {
728 ctrl4_set |= chan << LRADC_CTRL4_LRADCSELECT_OFFSET(ofs);
729 ctrl4_clr |= LRADC_CTRL4_LRADCSELECT_MASK(ofs);
730 ctrl1_irq |= LRADC_CTRL1_LRADC_IRQ_EN(ofs);
731 writel(chan_value, lradc->base + LRADC_CH(ofs));
732 bitmap_set(&enable, ofs, 1);
736 writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
737 lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
739 writel(ctrl4_clr, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_CLR);
740 writel(ctrl4_set, lradc->base + LRADC_CTRL4 + STMP_OFFSET_REG_SET);
742 writel(ctrl1_irq, lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_SET);
744 writel(enable << LRADC_DELAY_TRIGGER_LRADCS_OFFSET,
745 lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_SET);
750 kfree(lradc->buffer);
752 mutex_unlock(&lradc->lock);
756 static int mxs_lradc_buffer_postdisable(struct iio_dev *iio)
758 struct mxs_lradc *lradc = iio_priv(iio);
760 writel(LRADC_DELAY_TRIGGER_LRADCS_MASK | LRADC_DELAY_KICK,
761 lradc->base + LRADC_DELAY(0) + STMP_OFFSET_REG_CLR);
763 writel(0xff, lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
764 writel(LRADC_CTRL1_LRADC_IRQ_EN_MASK,
765 lradc->base + LRADC_CTRL1 + STMP_OFFSET_REG_CLR);
767 kfree(lradc->buffer);
768 mutex_unlock(&lradc->lock);
773 static bool mxs_lradc_validate_scan_mask(struct iio_dev *iio,
774 const unsigned long *mask)
776 struct mxs_lradc *lradc = iio_priv(iio);
777 const int len = iio->masklength;
778 const int map_chans = bitmap_weight(mask, len);
780 unsigned long rsvd_mask = 0;
782 if (lradc->use_touchbutton)
783 rsvd_mask |= CHAN_MASK_TOUCHBUTTON;
784 if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_4WIRE)
785 rsvd_mask |= CHAN_MASK_TOUCHSCREEN_4WIRE;
786 if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE)
787 rsvd_mask |= CHAN_MASK_TOUCHSCREEN_5WIRE;
789 if (lradc->use_touchbutton)
791 if (lradc->use_touchscreen)
794 /* Test for attempts to map channels with special mode of operation. */
795 if (bitmap_intersects(mask, &rsvd_mask, len))
798 /* Test for attempts to map more channels then available slots. */
799 if (map_chans + rsvd_chans > LRADC_MAX_MAPPED_CHANS)
805 static const struct iio_buffer_setup_ops mxs_lradc_buffer_ops = {
806 .preenable = &mxs_lradc_buffer_preenable,
807 .postenable = &iio_triggered_buffer_postenable,
808 .predisable = &iio_triggered_buffer_predisable,
809 .postdisable = &mxs_lradc_buffer_postdisable,
810 .validate_scan_mask = &mxs_lradc_validate_scan_mask,
814 * Driver initialization
817 #define MXS_ADC_CHAN(idx, chan_type) { \
818 .type = (chan_type), \
820 .scan_index = (idx), \
821 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
830 static const struct iio_chan_spec mxs_lradc_chan_spec[] = {
831 MXS_ADC_CHAN(0, IIO_VOLTAGE),
832 MXS_ADC_CHAN(1, IIO_VOLTAGE),
833 MXS_ADC_CHAN(2, IIO_VOLTAGE),
834 MXS_ADC_CHAN(3, IIO_VOLTAGE),
835 MXS_ADC_CHAN(4, IIO_VOLTAGE),
836 MXS_ADC_CHAN(5, IIO_VOLTAGE),
837 MXS_ADC_CHAN(6, IIO_VOLTAGE),
838 MXS_ADC_CHAN(7, IIO_VOLTAGE), /* VBATT */
839 MXS_ADC_CHAN(8, IIO_TEMP), /* Temp sense 0 */
840 MXS_ADC_CHAN(9, IIO_TEMP), /* Temp sense 1 */
841 MXS_ADC_CHAN(10, IIO_VOLTAGE), /* VDDIO */
842 MXS_ADC_CHAN(11, IIO_VOLTAGE), /* VTH */
843 MXS_ADC_CHAN(12, IIO_VOLTAGE), /* VDDA */
844 MXS_ADC_CHAN(13, IIO_VOLTAGE), /* VDDD */
845 MXS_ADC_CHAN(14, IIO_VOLTAGE), /* VBG */
846 MXS_ADC_CHAN(15, IIO_VOLTAGE), /* VDD5V */
849 static void mxs_lradc_hw_init(struct mxs_lradc *lradc)
851 /* The ADC always uses DELAY CHANNEL 0. */
852 const uint32_t adc_cfg =
853 (1 << (LRADC_DELAY_TRIGGER_DELAYS_OFFSET + 0)) |
854 (LRADC_DELAY_TIMER_PER << LRADC_DELAY_DELAY_OFFSET);
856 stmp_reset_block(lradc->base);
858 /* Configure DELAY CHANNEL 0 for generic ADC sampling. */
859 writel(adc_cfg, lradc->base + LRADC_DELAY(0));
861 /* Disable remaining DELAY CHANNELs */
862 writel(0, lradc->base + LRADC_DELAY(1));
863 writel(0, lradc->base + LRADC_DELAY(2));
864 writel(0, lradc->base + LRADC_DELAY(3));
866 /* Configure the touchscreen type */
867 writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE,
868 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_CLR);
870 if (lradc->use_touchscreen == MXS_LRADC_TOUCHSCREEN_5WIRE) {
871 writel(LRADC_CTRL0_TOUCH_SCREEN_TYPE,
872 lradc->base + LRADC_CTRL0 + STMP_OFFSET_REG_SET);
875 /* Start internal temperature sensing. */
876 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 = iio_device_alloc(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 ret = PTR_ERR(lradc->base);
930 INIT_WORK(&lradc->ts_work, mxs_lradc_ts_work);
932 /* Check if touchscreen is enabled in DT. */
933 ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
936 dev_info(dev, "Touchscreen not enabled.\n");
937 else if (ts_wires == 4)
938 lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_4WIRE;
939 else if (ts_wires == 5)
940 lradc->use_touchscreen = MXS_LRADC_TOUCHSCREEN_5WIRE;
942 dev_warn(dev, "Unsupported number of touchscreen wires (%d)\n",
945 /* Grab all IRQ sources */
946 for (i = 0; i < of_cfg->irq_count; i++) {
947 lradc->irq[i] = platform_get_irq(pdev, i);
948 if (lradc->irq[i] < 0) {
953 ret = devm_request_irq(dev, lradc->irq[i],
954 mxs_lradc_handle_irq, 0,
955 of_cfg->irq_name[i], iio);
960 platform_set_drvdata(pdev, iio);
962 init_completion(&lradc->completion);
963 mutex_init(&lradc->lock);
965 iio->name = pdev->name;
966 iio->dev.parent = &pdev->dev;
967 iio->info = &mxs_lradc_iio_info;
968 iio->modes = INDIO_DIRECT_MODE;
969 iio->channels = mxs_lradc_chan_spec;
970 iio->num_channels = ARRAY_SIZE(mxs_lradc_chan_spec);
972 ret = iio_triggered_buffer_setup(iio, &iio_pollfunc_store_time,
973 &mxs_lradc_trigger_handler,
974 &mxs_lradc_buffer_ops);
978 ret = mxs_lradc_trigger_init(iio);
982 /* Configure the hardware. */
983 mxs_lradc_hw_init(lradc);
985 /* Register the touchscreen input device. */
986 ret = mxs_lradc_ts_register(lradc);
990 /* Register IIO device. */
991 ret = iio_device_register(iio);
993 dev_err(dev, "Failed to register IIO device\n");
1000 mxs_lradc_ts_unregister(lradc);
1002 mxs_lradc_trigger_remove(iio);
1004 iio_triggered_buffer_cleanup(iio);
1006 iio_device_free(iio);
1010 static int mxs_lradc_remove(struct platform_device *pdev)
1012 struct iio_dev *iio = platform_get_drvdata(pdev);
1013 struct mxs_lradc *lradc = iio_priv(iio);
1015 mxs_lradc_ts_unregister(lradc);
1017 mxs_lradc_hw_stop(lradc);
1019 iio_device_unregister(iio);
1020 iio_triggered_buffer_cleanup(iio);
1021 mxs_lradc_trigger_remove(iio);
1022 iio_device_free(iio);
1027 static struct platform_driver mxs_lradc_driver = {
1029 .name = DRIVER_NAME,
1030 .owner = THIS_MODULE,
1031 .of_match_table = mxs_lradc_dt_ids,
1033 .probe = mxs_lradc_probe,
1034 .remove = mxs_lradc_remove,
1037 module_platform_driver(mxs_lradc_driver);
1039 MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
1040 MODULE_DESCRIPTION("Freescale i.MX28 LRADC driver");
1041 MODULE_LICENSE("GPL v2");