Re: [PATCH v4 24/24] drm/exynos: dsi: Adjust probe order

[Andrzej Hajda <a.hajda@samsung.com>]

W dniu 10.09.2021 o 12:12, Maxime Ripard pisze:
> Without proper care and an agreement between how DSI hosts and devices
> drivers register their MIPI-DSI entities and potential components, we can
> end up in a situation where the drivers can never probe.
>
> Most drivers were taking evasive maneuvers to try to workaround this,
> but not all of them were following the same conventions, resulting in
> various incompatibilities between DSI hosts and devices.
>
> Now that we have a sequence agreed upon and documented, let's convert
> exynos to it.
>
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>

This patch should be dropped, as it will probably break the driver.

Exynos is already compatible with the pattern 
register-bus-then-get-sink, but it adds/removes panel/bridge 
dynamically, so it creates drm_device without waiting for downstream sink.


Regards

Andrzej


> ---
>   drivers/gpu/drm/exynos/exynos_drm_dsi.c | 19 ++++++++++++-------
>   1 file changed, 12 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> index e39fac889edc..dfda2b259c44 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> @@ -1529,6 +1529,7 @@ static const struct drm_encoder_helper_funcs exynos_dsi_encoder_helper_funcs = {
>   
>   MODULE_DEVICE_TABLE(of, exynos_dsi_of_match);
>   
> +static const struct component_ops exynos_dsi_component_ops;
>   static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
>   				  struct mipi_dsi_device *device)
>   {
> @@ -1536,6 +1537,7 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
>   	struct drm_encoder *encoder = &dsi->encoder;
>   	struct drm_device *drm = encoder->dev;
>   	struct drm_bridge *out_bridge;
> +	struct device *dev = host->dev;
>   
>   	out_bridge  = of_drm_find_bridge(device->dev.of_node);
>   	if (out_bridge) {
> @@ -1585,7 +1587,7 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
>   	if (drm->mode_config.poll_enabled)
>   		drm_kms_helper_hotplug_event(drm);
>   
> -	return 0;
> +	return component_add(dev, &exynos_dsi_component_ops);
>   }
>   
>   static int exynos_dsi_host_detach(struct mipi_dsi_host *host,
> @@ -1593,6 +1595,9 @@ static int exynos_dsi_host_detach(struct mipi_dsi_host *host,
>   {
>   	struct exynos_dsi *dsi = host_to_dsi(host);
>   	struct drm_device *drm = dsi->encoder.dev;
> +	struct device *dev = host->dev;
> +
> +	component_del(dev, &exynos_dsi_component_ops);
>   
>   	if (dsi->panel) {
>   		mutex_lock(&drm->mode_config.mutex);
> @@ -1716,7 +1721,7 @@ static int exynos_dsi_bind(struct device *dev, struct device *master,
>   		of_node_put(in_bridge_node);
>   	}
>   
> -	return mipi_dsi_host_register(&dsi->dsi_host);
> +	return 0;
>   }
>   
>   static void exynos_dsi_unbind(struct device *dev, struct device *master,
> @@ -1726,8 +1731,6 @@ static void exynos_dsi_unbind(struct device *dev, struct device *master,
>   	struct drm_encoder *encoder = &dsi->encoder;
>   
>   	exynos_dsi_disable(encoder);
> -
> -	mipi_dsi_host_unregister(&dsi->dsi_host);
>   }
>   
>   static const struct component_ops exynos_dsi_component_ops = {
> @@ -1821,7 +1824,7 @@ static int exynos_dsi_probe(struct platform_device *pdev)
>   
>   	pm_runtime_enable(dev);
>   
> -	ret = component_add(dev, &exynos_dsi_component_ops);
> +	ret = mipi_dsi_host_register(&dsi->dsi_host);
>   	if (ret)
>   		goto err_disable_runtime;
>   
> @@ -1835,10 +1838,12 @@ static int exynos_dsi_probe(struct platform_device *pdev)
>   
>   static int exynos_dsi_remove(struct platform_device *pdev)
>   {
> +	struct exynos_dsi *dsi = platform_get_drvdata(pdev);
> +
> +	mipi_dsi_host_unregister(&dsi->dsi_host);
> +
>   	pm_runtime_disable(&pdev->dev);
>   
> -	component_del(&pdev->dev, &exynos_dsi_component_ops);
> -
>   	return 0;
>   }
>