[PATCH] drm/bridge: dw-mipi-dsi: Find the possible DSI devices

[yannick Fertre]

Hi Jagan,

Sorry for the delay. Thanks for the patch.

Tested-by: Yannick Fertre <yannick.fertre at foss.st.com>




On 7/4/21 4:03 PM, Jagan Teki wrote:
> Finding panel_or_bridge might vary based on associated
> DSI devices like DSI panel, bridge, and I2C based DSI
> bridge.
> 
> 1. DSI panels and bridges will invoke the host attach
>     from probe in order to find the panel_or_bridge.
> 
>     chipone_probe()
>         dw_mipi_dsi_host_attach().start
> 	   dw_mipi_dsi_panel_or_bridge()
> 		...found the panel_or_bridge...
> 
>     ltdc_encoder_init().start
>         dw_mipi_dsi_bridge_attach().start
> 		   dw_mipi_dsi_host_attach().start
> 		       chipone_attach(). start
> 
> 	               chipone_attach(). done
> 		   dw_mipi_dsi_host_attach().done
>         dw_mipi_dsi_bridge_attach(). done
>     ltdc_encoder_init().done
> 
> 2. I2C based DSI bridge will invoke the drm_bridge_attach
>     from bridge attach in order to find the panel_or_bridge.
> 
>     ltdc_encoder_init().start
>         dw_mipi_dsi_bridge_attach().start
> 	   dw_mipi_dsi_panel_or_bridge()
> 		...found the panel_or_bridge...
> 		   dw_mipi_dsi_host_attach().start
> 		       sn65dsi83_attach(). start
> 
> 	               sn65dsi83_attach(). done
> 		   dw_mipi_dsi_host_attach().done
>         dw_mipi_dsi_bridge_attach(). done
>     ltdc_encoder_init().done
> 
> So, invoke the panel_or_bridge from host attach and
> bridge attach in order to find all possible DSI devices.
> 
> Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>
> ---
>   drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 58 ++++++++++++++-----
>   1 file changed, 43 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> index 6b268f9445b3..45f4515dda00 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -246,6 +246,7 @@ struct dw_mipi_dsi {
>   
>   	struct clk *pclk;
>   
> +	bool device_found;
>   	unsigned int lane_mbps; /* per lane */
>   	u32 channel;
>   	u32 lanes;
> @@ -309,13 +310,37 @@ static inline u32 dsi_read(struct dw_mipi_dsi *dsi, u32 reg)
>   	return readl(dsi->base + reg);
>   }
>   
> +static int dw_mipi_dsi_panel_or_bridge(struct dw_mipi_dsi *dsi,
> +				       struct device_node *node)
> +{
> +	struct drm_bridge *bridge;
> +	struct drm_panel *panel;
> +	int ret;
> +
> +	ret = drm_of_find_panel_or_bridge(node, 1, 0, &panel, &bridge);
> +	if (ret)
> +		return ret;
> +
> +	if (panel) {
> +		bridge = drm_panel_bridge_add_typed(panel,
> +						    DRM_MODE_CONNECTOR_DSI);
> +		if (IS_ERR(bridge))
> +			return PTR_ERR(bridge);
> +	}
> +
> +	dsi->panel_bridge = bridge;
> +
> +	if (!dsi->panel_bridge)
> +		return -EPROBE_DEFER;
> +
> +	return 0;
> +}
> +
>   static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
>   				   struct mipi_dsi_device *device)
>   {
>   	struct dw_mipi_dsi *dsi = host_to_dsi(host);
>   	const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
> -	struct drm_bridge *bridge;
> -	struct drm_panel *panel;
>   	int ret;
>   
>   	if (device->lanes > dsi->plat_data->max_data_lanes) {
> @@ -329,22 +354,14 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
>   	dsi->format = device->format;
>   	dsi->mode_flags = device->mode_flags;
>   
> -	ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0,
> -					  &panel, &bridge);
> -	if (ret)
> -		return ret;
> +	if (!dsi->device_found) {
> +		ret = dw_mipi_dsi_panel_or_bridge(dsi, host->dev->of_node);
> +		if (ret)
> +			return ret;
>   
> -	if (panel) {
> -		bridge = drm_panel_bridge_add_typed(panel,
> -						    DRM_MODE_CONNECTOR_DSI);
> -		if (IS_ERR(bridge))
> -			return PTR_ERR(bridge);
> +		dsi->device_found = true;
>   	}
>   
> -	dsi->panel_bridge = bridge;
> -
> -	drm_bridge_add(&dsi->bridge);
> -
>   	if (pdata->host_ops && pdata->host_ops->attach) {
>   		ret = pdata->host_ops->attach(pdata->priv_data, device);
>   		if (ret < 0)
> @@ -999,6 +1016,16 @@ static int dw_mipi_dsi_bridge_attach(struct drm_bridge *bridge,
>   	/* Set the encoder type as caller does not know it */
>   	bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
>   
> +	if (!dsi->device_found) {
> +		int ret;
> +
> +		ret = dw_mipi_dsi_panel_or_bridge(dsi, dsi->dev->of_node);
> +		if (ret)
> +			return ret;
> +
> +		dsi->device_found = true;
> +	}
> +
>   	/* Attach the panel-bridge to the dsi bridge */
>   	return drm_bridge_attach(bridge->encoder, dsi->panel_bridge, bridge,
>   				 flags);
> @@ -1181,6 +1208,7 @@ __dw_mipi_dsi_probe(struct platform_device *pdev,
>   #ifdef CONFIG_OF
>   	dsi->bridge.of_node = pdev->dev.of_node;
>   #endif
> +	drm_bridge_add(&dsi->bridge);
>   
>   	return dsi;
>   }
>