drm/bridge: lt9611: Use both bits for HDMI sensing

In commit 19cf41b64e3b ("lontium-lt9611: check a different
register bit for HDMI sensing"), the bit flag used to detect
HDMI cable connect was switched from BIT(2) to BIT(0) to improve
compatibility with some monitors that didn't seem to set BIT(2).

However, with that change, I've seen occasional issues where the
detection failed, because BIT(2) was set, but not BIT(0).

Unfortunately, as I understand it, the bits and their function
was never clearly documented. So lets instead check both
(BIT(2) | BIT(0)) when checking the register.

Cc: Yongqin Liu <yongqin.liu@linaro.org>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Robert Foss <robert.foss@linaro.org>
Cc: kernel-team@android.com
Fixes: 19cf41b64e3b ("lontium-lt9611: check a different register bit for HDMI sensing")
Signed-off-by: John Stultz <jstultz@google.com>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Signed-off-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220511012612.3297577-2-jstultz@google.com

diff --git a/drivers/gpu/drm/bridge/lontium-lt9611.c b/drivers/gpu/drm/bridge/lontium-lt9611.c
index 08a9b60..88f2a4f 100644 (file)
--- a/drivers/gpu/drm/bridge/lontium-lt9611.c
+++ b/drivers/gpu/drm/bridge/lontium-lt9611.c
@@ -584,7 +584,7 @@ static enum drm_connector_status __lt9611_detect(struct lt9611 *lt9611)
        int connected = 0;
 
        regmap_read(lt9611->regmap, 0x825e, &reg_val);
-       connected  = (reg_val & BIT(0));
+       connected  = (reg_val & (BIT(2) | BIT(0)));
 
        lt9611->status = connected ?  connector_status_connected :
                                connector_status_disconnected;