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Commit fd746d54 authored by Eric Miao's avatar Eric Miao Committed by Dmitry Torokhov
Browse files

Input: ads7846 - introduce platform specific way to synchronize sampling 



Noises can be introduced when LCD signals are being driven, some platforms
provide a signal to assist the synchronization of this sampling procedure.

Signed-off-by: default avatarEric Miao <eric.miao@marvell.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent b79e83bd

drivers/input/touchscreen/ads7846.c

+10 −0
Original line number Diff line number Diff line
@@ -127,6 +127,8 @@ struct ads7846 { 
	void			(*filter_cleanup)(void *data);

	int			(*get_pendown_state)(void);

	int			gpio_pendown;



	void			(*wait_for_sync)(void);

};



/* leave chip selected when we're done, for quicker re-select? */
@@ -511,6 +513,10 @@ static int get_pendown_state(struct ads7846 *ts) 
	return !gpio_get_value(ts->gpio_pendown);

}



static void null_wait_for_sync(void)

{

}



/*

 * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,

 * to retrieve touchscreen status.
@@ -686,6 +692,7 @@ static void ads7846_rx_val(void *ads) 
	default:

		BUG();

	}

	ts->wait_for_sync();

	status = spi_async(ts->spi, m);

	if (status)

		dev_err(&ts->spi->dev, "spi_async --> %d\n",
@@ -723,6 +730,7 @@ static enum hrtimer_restart ads7846_timer(struct hrtimer *handle) 
	} else {

		/* pen is still down, continue with the measurement */

		ts->msg_idx = 0;

		ts->wait_for_sync();

		status = spi_async(ts->spi, &ts->msg[0]);

		if (status)

			dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
@@ -947,6 +955,8 @@ static int __devinit 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;



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



	input_dev->name = "ADS784x Touchscreen";

include/linux/spi/ads7846.h

+1 −0
Original line number Diff line number Diff line
@@ -51,5 +51,6 @@ struct ads7846_platform_data { 
				 void **filter_data);

	int	(*filter)	(void *filter_data, int data_idx, int *val);

	void	(*filter_cleanup)(void *filter_data);

	void	(*wait_for_sync)(void);

};