Re: [RFC PATCH 01/17] drm/exynos: dsi: Convert to bridge driver

[Sam Ravnborg <sam@ravnborg.org>]

Hi Jagan,

See a few comments below.

	Sam

On Sun, Jul 04, 2021 at 02:32:14PM +0530, Jagan Teki wrote:
> DRM bridge drivers have built-in handling of treating
> all display pipeline components as bridges.
> 
> Convert exynos_drm_dsi to a bridge driver with built-in
> encoder support for compatibility with existing component
> drivers.
> 
> This keeps switching the driver into the bridge in a more
> feasible manner.
> 
> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> ---
>  drivers/gpu/drm/exynos/exynos_drm_dsi.c | 57 +++++++++++++++++--------
>  1 file changed, 39 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> index 1d777d8c1a83..90d2ce2c3055 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> @@ -257,6 +257,7 @@ struct exynos_dsi {
>  	struct drm_connector connector;
>  	struct drm_panel *panel;
>  	struct list_head bridge_chain;
> +	struct drm_bridge bridge;
>  	struct drm_bridge *out_bridge;
>  	struct device *dev;
>  
> @@ -287,9 +288,9 @@ struct exynos_dsi {
>  #define host_to_dsi(host) container_of(host, struct exynos_dsi, dsi_host)
>  #define connector_to_dsi(c) container_of(c, struct exynos_dsi, connector)
>  
> -static inline struct exynos_dsi *encoder_to_dsi(struct drm_encoder *e)
> +static inline struct exynos_dsi *bridge_to_dsi(struct drm_bridge *b)
>  {
> -	return container_of(e, struct exynos_dsi, encoder);
> +	return container_of(b, struct exynos_dsi, bridge);
>  }
>  
>  enum reg_idx {
> @@ -1374,9 +1375,9 @@ static void exynos_dsi_unregister_te_irq(struct exynos_dsi *dsi)
>  	}
>  }
>  
> -static void exynos_dsi_enable(struct drm_encoder *encoder)
> +static void exynos_dsi_bridge_enable(struct drm_bridge *bridge)
>  {
> -	struct exynos_dsi *dsi = encoder_to_dsi(encoder);
> +	struct exynos_dsi *dsi = bridge_to_dsi(bridge);
>  	struct drm_bridge *iter;
>  	int ret;
>  
> @@ -1429,9 +1430,9 @@ static void exynos_dsi_enable(struct drm_encoder *encoder)
>  	pm_runtime_put(dsi->dev);
>  }
>  
> -static void exynos_dsi_disable(struct drm_encoder *encoder)
> +static void exynos_dsi_bridge_disable(struct drm_bridge *bridge)
>  {
> -	struct exynos_dsi *dsi = encoder_to_dsi(encoder);
> +	struct exynos_dsi *dsi = bridge_to_dsi(bridge);
>  	struct drm_bridge *iter;
>  
>  	if (!(dsi->state & DSIM_STATE_ENABLED))
> @@ -1494,9 +1495,9 @@ static const struct drm_connector_helper_funcs exynos_dsi_connector_helper_funcs
>  	.get_modes = exynos_dsi_get_modes,
>  };
>  
> -static int exynos_dsi_create_connector(struct drm_encoder *encoder)
> +static int exynos_dsi_create_connector(struct exynos_dsi *dsi)
>  {
> -	struct exynos_dsi *dsi = encoder_to_dsi(encoder);
> +	struct drm_encoder *encoder = &dsi->encoder;
>  	struct drm_connector *connector = &dsi->connector;
>  	struct drm_device *drm = encoder->dev;
>  	int ret;
> @@ -1522,9 +1523,16 @@ static int exynos_dsi_create_connector(struct drm_encoder *encoder)
>  	return 0;
>  }
>  
> -static const struct drm_encoder_helper_funcs exynos_dsi_encoder_helper_funcs = {
> -	.enable = exynos_dsi_enable,
> -	.disable = exynos_dsi_disable,
> +static int exynos_dsi_bridge_attach(struct drm_bridge *bridge,
> +				    enum drm_bridge_attach_flags flags)
> +{
> +	return 0;
> +}
> +
> +static const struct drm_bridge_funcs exynos_dsi_bridge_funcs = {
> +	.enable = exynos_dsi_bridge_enable,
> +	.disable = exynos_dsi_bridge_disable,
> +	.attach = exynos_dsi_bridge_attach,
>  };
For new bridge drivers please use atomic_{enable,disable}.
The non-atomic variants are deprecated and it is now also documneted.
It was not documented when you wrote this patch!

	Sam
>  
>  MODULE_DEVICE_TABLE(of, exynos_dsi_of_match);
> @@ -1543,7 +1551,7 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
>  		dsi->out_bridge = out_bridge;
>  		list_splice_init(&encoder->bridge_chain, &dsi->bridge_chain);
>  	} else {
> -		int ret = exynos_dsi_create_connector(encoder);
> +		int ret = exynos_dsi_create_connector(dsi);
>  
>  		if (ret) {
>  			DRM_DEV_ERROR(dsi->dev,
> @@ -1596,7 +1604,7 @@ static int exynos_dsi_host_detach(struct mipi_dsi_host *host,
>  
>  	if (dsi->panel) {
>  		mutex_lock(&drm->mode_config.mutex);
> -		exynos_dsi_disable(&dsi->encoder);
> +		exynos_dsi_bridge_disable(&dsi->bridge);
>  		dsi->panel = NULL;
>  		dsi->connector.status = connector_status_disconnected;
>  		mutex_unlock(&drm->mode_config.mutex);
> @@ -1702,12 +1710,16 @@ static int exynos_dsi_bind(struct device *dev, struct device *master,
>  
>  	drm_simple_encoder_init(drm_dev, encoder, DRM_MODE_ENCODER_TMDS);
>  
> -	drm_encoder_helper_add(encoder, &exynos_dsi_encoder_helper_funcs);
> -
>  	ret = exynos_drm_set_possible_crtcs(encoder, EXYNOS_DISPLAY_TYPE_LCD);
>  	if (ret < 0)
>  		return ret;
>  
> +	ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL, 0);

I assume a later patch will move connector creation to the display
driver.


> +	if (ret) {
> +		drm_encoder_cleanup(&dsi->encoder);
> +		return ret;
> +	}
> +
>  	in_bridge_node = of_graph_get_remote_node(dev->of_node, DSI_PORT_IN, 0);
>  	if (in_bridge_node) {
>  		in_bridge = of_drm_find_bridge(in_bridge_node);
> @@ -1723,10 +1735,9 @@ static void exynos_dsi_unbind(struct device *dev, struct device *master,
>  				void *data)
>  {
>  	struct exynos_dsi *dsi = dev_get_drvdata(dev);
> -	struct drm_encoder *encoder = &dsi->encoder;
> -
> -	exynos_dsi_disable(encoder);
>  
> +	exynos_dsi_bridge_disable(&dsi->bridge);
> +	drm_encoder_cleanup(&dsi->encoder);
>  	mipi_dsi_host_unregister(&dsi->dsi_host);
>  }
>  
> @@ -1821,6 +1832,12 @@ static int exynos_dsi_probe(struct platform_device *pdev)
>  
>  	pm_runtime_enable(dev);
>  
> +	dsi->bridge.funcs = &exynos_dsi_bridge_funcs;
> +	dsi->bridge.of_node = dev->of_node;
> +	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
> +
> +	drm_bridge_add(&dsi->bridge);
> +
>  	ret = component_add(dev, &exynos_dsi_component_ops);
>  	if (ret)
>  		goto err_disable_runtime;
> @@ -1835,6 +1852,10 @@ 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);
> +
> +	drm_bridge_remove(&dsi->bridge);
> +
>  	pm_runtime_disable(&pdev->dev);
>  
>  	component_del(&pdev->dev, &exynos_dsi_component_ops);
> -- 
> 2.25.1

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