diff options
| author | Oleksij Rempel <o.rempel@pengutronix.de> | 2021-10-15 21:12:06 -0700 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2021-10-15 22:11:03 -0700 |
| commit | fe0a7e3d012738b0034b3c97ddb0e8bc0a3ff0e6 (patch) | |
| tree | bdf797ed679a3639aa1053d51a5e8822a6611e36 | |
| parent | d997cc1715df7b6c3df798881fb9941acf0079f8 (diff) | |
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: 60b7db914ddd ("Input: resistive-adc-touch - rework mapping of channels")
Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20211007095727.29579-1-o.rempel@pengutronix.de
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
| -rw-r--r-- | drivers/input/touchscreen/resistive-adc-touch.c | 29 |
1 files changed, 16 insertions, 13 deletions
diff --git a/drivers/input/touchscreen/resistive-adc-touch.c b/drivers/input/touchscreen/resistive-adc-touch.c index 744544a723b7..6f754a8d30b1 100644 --- a/drivers/input/touchscreen/resistive-adc-touch.c +++ b/drivers/input/touchscreen/resistive-adc-touch.c @@ -71,19 +71,22 @@ static int grts_cb(const void *data, void *private) unsigned int z2 = touch_info[st->ch_map[GRTS_CH_Z2]]; unsigned int Rt; - Rt = z2; - Rt -= z1; - Rt *= st->x_plate_ohms; - Rt = DIV_ROUND_CLOSEST(Rt, 16); - Rt *= x; - 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. - */ - if (Rt < GRTS_DEFAULT_PRESSURE_MAX) - press = GRTS_DEFAULT_PRESSURE_MAX - Rt; + if (likely(x && z1)) { + Rt = z2; + Rt -= z1; + Rt *= st->x_plate_ohms; + Rt = DIV_ROUND_CLOSEST(Rt, 16); + Rt *= x; + 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. + */ + if (Rt < GRTS_DEFAULT_PRESSURE_MAX) + press = GRTS_DEFAULT_PRESSURE_MAX - Rt; + } } if ((!x && !y) || (st->pressure && (press < st->pressure_min))) { |