Commit fe0a7e3d authored by Oleksij Rempel's avatar Oleksij Rempel Committed by Dmitry Torokhov
Browse files

Input: resistive-adc-touch - fix division by zero error on z1 == 0 



For proper pressure calculation we need at least x and z1 to be non
zero. Even worse, in case z1 we may run in to division by zero
error.

Fixes: 60b7db91 ("Input: resistive-adc-touch - rework mapping of channels")
Signed-off-by: default avatarOleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20211007095727.29579-1-o.rempel@pengutronix.de


Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent d997cc17

drivers/input/touchscreen/resistive-adc-touch.c

+16 −13
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ static int grts_cb(const void *data, void *private) 
		unsigned int z2 = touch_info[st->ch_map[GRTS_CH_Z2]];

		unsigned int Rt;



		if (likely(x && z1)) {

			Rt = z2;

			Rt -= z1;

			Rt *= st->x_plate_ohms;
@@ -79,12 +80,14 @@ static int grts_cb(const void *data, void *private) 
			Rt /= z1;

			Rt = DIV_ROUND_CLOSEST(Rt, 256);

			/*

		 * On increased pressure the resistance (Rt) is decreasing

		 * so, convert values to make it looks as real pressure.

			 * On increased pressure the resistance (Rt) is

			 * decreasing so, convert values to make it looks as

			 * real pressure.

			 */

			if (Rt < GRTS_DEFAULT_PRESSURE_MAX)

				press = GRTS_DEFAULT_PRESSURE_MAX - Rt;

		}

	}



	if ((!x && !y) || (st->pressure && (press < st->pressure_min))) {

		/* report end of touch */