* [PATCH 2/2] Input: adafruit-seesaw: fix "flat" value to avoid drifting
[not found] <20250716174422.860500-1-michael.opdenacker@rootcommit.com>
@ 2025-07-16 17:44 ` michael.opdenacker
0 siblings, 0 replies; only message in thread
From: michael.opdenacker @ 2025-07-16 17:44 UTC (permalink / raw)
To: anshulusr, dmitry.torokhov; +Cc: linux-input, linux-kernel, Michael Opdenacker
From: Michael Opdenacker <michael.opdenacker@rootcommit.com>
Tests on 9 Adafruit Mini I2C Gamepad devices have shown that
the center X and Y values (when the joystick is left at its center position)
deviate from 511, which is the center of the [0, 1023] value range:
Device Center X Vs. Expected (511) Center Y Vs. Expected (511)
1 519 8 493 -18
2 524 13 518 7 Not very stable data!
3 508 -3 531 20
4 531 20 508 -3
5 505 -6 521 10
6 519 8 477 -34 Big outlier, ignored!
7 519 8 524 13
8 524 13 510 -1
9 517 6 511 0
This change causes any X and Y value that is withing a [-20, +20]
interval around 511, to be reported as centered. This avoids
unwanted drifting (towards left, right, top or bottom)
and makes playing with this device easier.
Signed-off-by: Michael Opdenacker <michael.opdenacker@rootcommit.com>
---
drivers/input/joystick/adafruit-seesaw.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/input/joystick/adafruit-seesaw.c b/drivers/input/joystick/adafruit-seesaw.c
index 2b18451a0953..03eb181d5aef 100644
--- a/drivers/input/joystick/adafruit-seesaw.c
+++ b/drivers/input/joystick/adafruit-seesaw.c
@@ -50,7 +50,7 @@
#define SEESAW_JOYSTICK_MAX_AXIS 1023
#define SEESAW_JOYSTICK_FUZZ 2
-#define SEESAW_JOYSTICK_FLAT 4
+#define SEESAW_JOYSTICK_FLAT 20
#define SEESAW_GAMEPAD_POLL_INTERVAL_MS 16
#define SEESAW_GAMEPAD_POLL_MIN 8
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