On Thu, Dec 19, 2024 at 04:05:57PM +0800, Damon Ding wrote:
> The rockchip_dp_of_panel_on_aux_bus() helps to check whether the DT
> configurations related to the DP AUX bus are correct or not.
>
> If failed to get the panel from the platform bus, it is good to try
> the DP AUX bus. Then, the probing process will continue until it enters
> the analogix_dp_bind(), where devm_of_dp_aux_populate_bus() is called
> after &analogix_dp_device.aux has been initialized.
No. devm_of_dp_aux_populate_bus() should be called before bind(). And
bind should only be called from the done_probing() callback. The reason
is very simple: the panel driver might be built as a module and might be
not available when the analogix driver is being probed.
Also, please invert the logic of the commit message (and the driver).
The platform bus should be a fallback if there is no AUX bus panel, not
other way around.
>
> Signed-off-by: Damon Ding <damon.ding@xxxxxxxxxxxxxx>
> ---
> .../gpu/drm/rockchip/analogix_dp-rockchip.c | 24 +++++++++++++++++--
> 1 file changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
> index ba5263f85ee2..60c902abf40b 100644
> --- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
> +++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
> @@ -317,6 +317,24 @@ static const struct drm_encoder_helper_funcs rockchip_dp_encoder_helper_funcs =
> .atomic_check = rockchip_dp_drm_encoder_atomic_check,
> };
>
> +static bool rockchip_dp_of_panel_on_aux_bus(const struct device_node *np)
> +{
> + struct device_node *bus_node, *panel_node;
> +
> + bus_node = of_get_child_by_name(np, "aux-bus");
> + if (!bus_node)
> + return false;
> +
> + panel_node = of_get_child_by_name(bus_node, "panel");
> + of_node_put(bus_node);
> + if (!panel_node)
> + return false;
> +
> + of_node_put(panel_node);
> +
> + return true;
> +}
> +
> static int rockchip_dp_of_probe(struct rockchip_dp_device *dp)
> {
> struct device *dev = dp->dev;
> @@ -435,8 +453,10 @@ static int rockchip_dp_probe(struct platform_device *pdev)
> return -ENODEV;
>
> ret = drm_of_find_panel_or_bridge(dev->of_node, 1, 0, &panel, NULL);
> - if (ret < 0)
> - return ret;
> + if (ret < 0) {
> + if (!rockchip_dp_of_panel_on_aux_bus(dev->of_node))
> + return ret;
> + }
>
> dp = devm_kzalloc(dev, sizeof(*dp), GFP_KERNEL);
> if (!dp)
> --
> 2.34.1
>
--
With best wishes
Dmitry
