drm/msm/dsi: set default num_data_lanes

[ Upstream commit cd92cc187c053ab010a1570e2d61d68394a5c725 ]

If "data_lanes" property of the dsi output endpoint is missing in
the DT, num_data_lanes would be 0 by default, which could cause
dsi_host_attach() to fail if dsi->lanes is set to a non-zero value
by the bridge driver.

According to the binding document of msm dsi controller, the
input/output endpoint of the controller is expected to have 4 lanes.
So let's set num_data_lanes to 4 by default.

Signed-off-by: Philip Chen <philipchen@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20211030100812.1.I6cd9af36b723fed277d34539d3b2ba4ca233ad2d@changeid
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index ef4e81d7744646763880a27e41d6d17d8c3a9201..d49f1774811950504069eb81679217f07e864209 100644 (file)
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1563,6 +1563,8 @@ static int dsi_host_parse_lane_data(struct msm_dsi_host *msm_host,
        if (!prop) {
                dev_dbg(dev,
                        "failed to find data lane mapping, using default\n");
+               /* Set the number of date lanes to 4 by default. */
+               msm_host->num_data_lanes = 4;
                return 0;
        }