drm/bridge: adv7511: Re-write the i2c address before EDID probing
authorJohn Stultz <john.stultz@linaro.org>
Tue, 17 Jan 2017 00:52:52 +0000 (16:52 -0800)
committerArchit Taneja <architt@codeaurora.org>
Thu, 19 Jan 2017 03:46:58 +0000 (09:16 +0530)
commit3587c856675c45809010c2cee5b21096f6e8e938
tree6cc9d7490696173f5d624cf0c02ef032e5dac5c0
parent4226d9b127cf4758ba0e07931b3f0d59f1b1a50c
drm/bridge: adv7511: Re-write the i2c address before EDID probing

I've found that by just turning the chip on and off via the
POWER_DOWN register, I end up getting i2c_transfer errors on
HiKey.

Investigating further, it turns out that some of the register
state in hardware is getting lost, as the device registers are
reset when the chip is powered down.

Thus this patch simply re-writes the i2c address to the
ADV7511_REG_EDID_I2C_ADDR register to ensure its properly set
before we try to read the EDID data.

Cc: David Airlie <airlied@linux.ie>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Wolfram Sang <wsa+renesas@sang-engineering.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1484614372-15342-7-git-send-email-john.stultz@linaro.org
drivers/gpu/drm/bridge/adv7511/adv7511_drv.c