4.14-stable review patch. If anyone has any objections, please let me know.
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From: Lucas Stach l.stach@pengutronix.de
[ 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 | 3 +++ 1 file changed, 3 insertions(+)
--- a/drivers/gpu/drm/imx/imx-ldb.c +++ b/drivers/gpu/drm/imx/imx-ldb.c @@ -612,6 +612,9 @@ static int imx_ldb_bind(struct device *d return PTR_ERR(imx_ldb->regmap); }
+ /* disable LDB by resetting the control register to POR default */ + regmap_write(imx_ldb->regmap, IOMUXC_GPR2, 0); + imx_ldb->dev = dev;
if (of_id)