The direction detection logic in quarter-period mode was inconsistent
with half-period and full-period modes when using GRAY encoding.
According to the GRAY encoding state sequence for positive(clockwise)
rotation - 3->2->1->0 - in function get_state, the quarter-period mode
current interprets this as negative direction, while counter-clockwise
becomes positive. This leads to revesed interpretation compared to the
other 2 modes.
This patch corrects the quarter-period direction logic, maintaining
consistency across all encoding modes.
Tested on encoder with 2000 PPR, confirmed correct direction detection
after this patch.
Signed-off-by: Wang Peng <wangpeng@xxxxxxxxxxxx>
---
drivers/input/misc/rotary_encoder.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
index f706e1997..9be84380b 100644
--- a/drivers/input/misc/rotary_encoder.c
+++ b/drivers/input/misc/rotary_encoder.c
@@ -163,10 +163,10 @@ static irqreturn_t rotary_encoder_quarter_period_irq(int irq, void *dev_id)
state = rotary_encoder_get_state(encoder);
if ((encoder->last_stable + 1) % 4 == state) {
- encoder->dir = 1;
+ encoder->dir = -1;
rotary_encoder_report_event(encoder);
} else if (encoder->last_stable == (state + 1) % 4) {
- encoder->dir = -1;
+ encoder->dir = 1;
rotary_encoder_report_event(encoder);
}
--
2.50.0
