drm/imx: imx-ldb: disable LDB on driver bind
authorLucas Stach <l.stach@pengutronix.de>
Wed, 11 Apr 2018 15:31:35 +0000 (17:31 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 5 Sep 2018 07:26:24 +0000 (09:26 +0200)
commita43eac2d855be9f441b0c6e277bdaf878b07a370
tree25163760a37cd00e7a2b7ace4f6ffa794d1645d7
parent9ac1a4644bb8ff4343f9424ab6b3ab6db0f86c4a
drm/imx: imx-ldb: disable LDB on driver bind

[ Upstream commit b58262396fabd43dc869b576e3defdd23b32fe94 ]

The LVDS signal integrity is only guaranteed when the correct enable
sequence (first IPU DI, then LDB) is used. If the LDB display output was
active before the imx-drm driver is loaded (like when a bootsplash was
active) the DI will be disabled by the full IPU reset we do when loading
the driver. The LDB control registers are not part of the IPU range and
thus will remain unchanged.

This leads to the LDB still being active when the DI is getting enabled,
effectively reversing the required enable sequence. Fix this by also
disabling the LDB on driver bind.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/gpu/drm/imx/imx-ldb.c