[PATCH v13 04/18] drm: exynos: dsi: Switch to DSI panel or bridge find helper

[Marek Vasut]

On 2/27/23 12:39, Jagan Teki wrote:
> drm_of_dsi_find_panel_or_bridge is capable of looking up the
> downstream DSI bridge and panel and trying to add a panel bridge
> if the panel is found.
> 
> Replace explicit finding calls with drm_of_dsi_find_panel_or_bridge
> followed with drmm_panel_bridge_add.
> 
> Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>
> ---
> Changes for v13, v12, v11:
> - none
> Changes for v10:
> - new patch
> 
>   drivers/gpu/drm/exynos/exynos_drm_dsi.c | 25 +++++++++++++------------
>   1 file changed, 13 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> index df15501b1075..12a6dd987e8f 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> @@ -25,6 +25,7 @@
>   #include <drm/drm_atomic_helper.h>
>   #include <drm/drm_bridge.h>
>   #include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_of.h>
>   #include <drm/drm_panel.h>
>   #include <drm/drm_print.h>
>   #include <drm/drm_probe_helper.h>
> @@ -1470,24 +1471,26 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
>   	struct device *dev = dsi->dev;
>   	struct drm_encoder *encoder = &dsi->encoder;
>   	struct drm_device *drm = encoder->dev;
> +	struct drm_bridge *bridge;
>   	struct drm_panel *panel;
>   	int ret;
>   
> -	panel = of_drm_find_panel(device->dev.of_node);
> -	if (!IS_ERR(panel)) {
> -		dsi->out_bridge = devm_drm_panel_bridge_add(dev, panel);
> -	} else {
> -		dsi->out_bridge = of_drm_find_bridge(device->dev.of_node);
> -		if (!dsi->out_bridge)
> -			dsi->out_bridge = ERR_PTR(-EINVAL);
> -	}

As far as I understand this from my conversation with Maxime (please put 
him on CC of V15), the change here should instead perform the panel look 
up NOT in exynos_dsi_host_attach() , but in exynos_dsi_bind() , i.e. in 
the component_ops .bind callback . Here is an example of correct 
implementation:

https://cgit.freedesktop.org/drm-misc/tree/drivers/gpu/drm/vc4/vc4_dsi.c#n1805

In 14/18 patch, the same should be added to generic_dsim_register_host() 
, which is called from the driver .probe() callback, but that is OK.

With that implemented, you shouldn't need patches 1,2,3/18 anymore , so 
they can be dropped . And with this fixed, I think the driver should be 
good to be picked.

Please correct me if I'm wrong here.