Commit 8685f22b authored by Linus Walleij's avatar Linus Walleij Committed by Dmitry Torokhov
Browse files

Input: ads7846 - handle HSYNC GPIO 



Add handling of HSYNC signal emitted by the TI ADS7846 if it is hooked
up to a GPIO.

Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20240430-gpio-leds-miscarm-v1-3-9c94d7711f6c@linaro.org


[dtor: dropped Spitz changes, kept platform data wait_for_sync option]
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent e7202f64

drivers/input/touchscreen/ads7846.c

+29 −6
Original line number Diff line number Diff line
@@ -138,6 +138,7 @@ struct ads7846 { 
	void			*filter_data;

	int			(*get_pendown_state)(void);

	struct gpio_desc	*gpio_pendown;

	struct gpio_desc	*gpio_hsync;



	void			(*wait_for_sync)(void);

};
@@ -634,10 +635,6 @@ ATTRIBUTE_GROUPS(ads784x); 


/*--------------------------------------------------------------------------*/



static void null_wait_for_sync(void)

{

}



static int ads7846_debounce_filter(void *ads, int data_idx, int *val)

{

	struct ads7846 *ts = ads;
@@ -790,6 +787,28 @@ static int ads7846_filter(struct ads7846 *ts) 
	return 0;

}



static void ads7846_wait_for_hsync(struct ads7846 *ts)

{

	if (ts->wait_for_sync) {

		ts->wait_for_sync();

		return;

	}



	if (!ts->gpio_hsync)

		return;



	/*

	 * Wait for HSYNC to assert the line should be flagged

	 * as active low so here we are waiting for it to assert

	 */

	while (!gpiod_get_value(ts->gpio_hsync))

		cpu_relax();



	/* Then we wait for it do de-assert */

	while (gpiod_get_value(ts->gpio_hsync))

		cpu_relax();

}



static void ads7846_read_state(struct ads7846 *ts)

{

	struct ads7846_packet *packet = ts->packet;
@@ -800,7 +819,7 @@ static void ads7846_read_state(struct ads7846 *ts) 
	packet->last_cmd_idx = 0;



	while (true) {

		ts->wait_for_sync();

		ads7846_wait_for_hsync(ts);



		m = &ts->msg[msg_idx];

		error = spi_sync(ts->spi, m);
@@ -1258,7 +1277,11 @@ static int ads7846_probe(struct spi_device *spi) 
		ts->penirq_recheck_delay_usecs =

				pdata->penirq_recheck_delay_usecs;



	ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;

	ts->wait_for_sync = pdata->wait_for_sync;



	ts->gpio_hsync = devm_gpiod_get_optional(dev, "ti,hsync", GPIOD_IN);

	if (IS_ERR(ts->gpio_hsync))

		return PTR_ERR(ts->gpio_hsync);



	snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev));

	snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);