[PATCH 5.16 0797/1039] Input: ti_am335x_tsc - set ADCREFM for X configuration

[Greg Kroah-Hartman]

From: Dario Binacchi <dariobin@xxxxxxxxx>

[ Upstream commit 73cca71a903202cddc8279fc76b2da4995da5bea ]

As reported by the STEPCONFIG[1-16] registered field descriptions of the
TI reference manual, for the ADC "in single ended, SEL_INM_SWC_3_0 must
be 1xxx".

Unlike the Y and Z coordinates, this bit has not been set for the step
configuration registers used to sample the X coordinate.

Fixes: 1b8be32e6914 ("Input: add support for TI Touchscreen controller")
Signed-off-by: Dario Binacchi <dariobin@xxxxxxxxx>
Link: https://lore.kernel.org/r/20211212125358.14416-2-dariobin@xxxxxxxxx
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/input/touchscreen/ti_am335x_tsc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
index 83e685557a197..fd3ffdd23470b 100644
--- a/drivers/input/touchscreen/ti_am335x_tsc.c
+++ b/drivers/input/touchscreen/ti_am335x_tsc.c
@@ -131,7 +131,8 @@ static void titsc_step_config(struct titsc *ts_dev)
 	u32 stepenable;
 
 	config = STEPCONFIG_MODE_HWSYNC |
-			STEPCONFIG_AVG_16 | ts_dev->bit_xp;
+			STEPCONFIG_AVG_16 | ts_dev->bit_xp |
+			STEPCONFIG_INM_ADCREFM;
 	switch (ts_dev->wires) {
 	case 4:
 		config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
-- 
2.34.1