On Fri, Mar 22, 2024 at 03:22:22PM +0200, Abel Vesa wrote:
> Instead of relying on different compatibles for eDP and DP, lookup
> the panel node in devicetree to figure out the connector type and
> then pass on that information to the PHY. External DP is not described
> in DT, therefore, assume it's eDP if panel node is present.
>
> Signed-off-by: Abel Vesa <abel.v...@linaro.org>
> ---
> drivers/gpu/drm/msm/dp/dp_display.c | 43
> +++++++++++++++++++++++++++++++++----
> 1 file changed, 39 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c
> b/drivers/gpu/drm/msm/dp/dp_display.c
> index c4cb82af5c2f..c9763f77c832 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -726,6 +726,14 @@ static int dp_init_sub_modules(struct dp_display_private
> *dp)
> if (IS_ERR(phy))
> return PTR_ERR(phy);
>
> + rc = phy_set_mode_ext(phy, PHY_MODE_DP,
> + dp->dp_display.is_edp ? PHY_SUBMODE_EDP :
> PHY_SUBMODE_DP);
> + if (rc) {
> + DRM_ERROR("failed to set phy submode, rc = %d\n", rc);
> + dp->catalog = NULL;
> + goto error;
> + }
> +
> dp->catalog = dp_catalog_get(dev);
> if (IS_ERR(dp->catalog)) {
> rc = PTR_ERR(dp->catalog);
> @@ -734,9 +742,7 @@ static int dp_init_sub_modules(struct dp_display_private
> *dp)
> goto error;
> }
>
> - dp->aux = dp_aux_get(dev, dp->catalog,
> - phy,
> - dp->dp_display.is_edp);
> + dp->aux = dp_aux_get(dev, dp->catalog, phy, dp->dp_display.is_edp);
> if (IS_ERR(dp->aux)) {
> rc = PTR_ERR(dp->aux);
> DRM_ERROR("failed to initialize aux, rc = %d\n", rc);
> @@ -1241,6 +1247,35 @@ static int dp_auxbus_done_probe(struct drm_dp_aux *aux)
> return dp_display_probe_tail(aux->dev);
> }
>
> +static int dp_display_get_connector_type(struct platform_device *pdev,
> + const struct msm_dp_desc *desc)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *aux_bus;
> + struct device_node *panel;
> + int ret = DRM_MODE_CONNECTOR_DisplayPort;
> +
> + /* legacy platforms specify connector type in match data */
> + if (desc->connector_type == DRM_MODE_CONNECTOR_eDP ||
> + desc->connector_type == DRM_MODE_CONNECTOR_DisplayPort)
> + return desc->connector_type;
> +
> + aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
> + if (!aux_bus)
> + goto out;
My compiler warns that if we take this code path, then you will
of_node_put(<uninitialized panel>) below.
> +
> + panel = of_get_child_by_name(aux_bus, "panel");
> + if (!panel)
> + goto out;
> +
> + ret = DRM_MODE_CONNECTOR_eDP;
My brain read this function as:
check something
if (error)
bailout!
check something
if (error)
bailout!
ret should be edp
I then have to scan the code again to figure out what ret is otherwise,
and convince myself that the error path is never an error, but a totally
normal case.
If you instead rely on the fact that both of_get_child_by_name() and
of_node_put() can be passed NULL, you can write this as:
static int fn(..) {
aux_bus = of_get_child_by_name(dev->of_node, "aux-bus");
panel = of_get_child_by_name(aux_bus, "panel");
if (panel)
connector_type = DRM_MODE_CONNECTOR_eDP;
else
connector_type = DRM_MODE_CONNECTOR_DisplayPort;
of_node_put(panel);
of_node_put(aux_bus);
return connector_type;
}
Much easier to read, and you don't even have to zero-initialize panel to
avoid that compiler warning.
Regards,
Bjorn
> +
> +out:
> + of_node_put(panel);
> + of_node_put(aux_bus);
> + return ret;
> +}
> +
> static int dp_display_probe(struct platform_device *pdev)
> {
> int rc = 0;
> @@ -1263,7 +1298,7 @@ static int dp_display_probe(struct platform_device
> *pdev)
> dp->dp_display.pdev = pdev;
> dp->name = "drm_dp";
> dp->id = desc->id;
> - dp->dp_display.connector_type = desc->connector_type;
> + dp->dp_display.connector_type = dp_display_get_connector_type(pdev,
> desc);
> dp->wide_bus_supported = desc->wide_bus_supported;
> dp->dp_display.is_edp =
> (dp->dp_display.connector_type == DRM_MODE_CONNECTOR_eDP);
>
> --
> 2.34.1
>
