[PATCH v3 3/7] drm: exynos: dsi: Convert to bridge driver

[Andrzej Hajda]

On 12.12.2021 19:14, Jagan Teki wrote:
> Convert the encoders to bridge drivers in order to standardize on
> a single API with built-in dumb encoder support for compatibility
> with existing component drivers.
>
> Driver bridge conversion will help to reuse the same bridge on
> different platforms as exynos dsi driver can be used as a Samsung
> DSIM and use it for i.MX8MM platform.
>
> Bridge conversion,
>
> - Drops drm_encoder_helper_funcs,
> bridge_chain.


I wonder how it will behave on setup with two bridges after exynos_dsi.


>
> - Adds drm_bridge_funcs and register a drm bridge.
>
> Convert it.
>
> Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>
> ---
> Changes for v3:
> - move bridge add in host_attach
> - move bridge remove in host_detach
> - use flags, bridge in drm_bridge_attach in attch
> Changes for v2:
> - drop bridge_chain
>
>   drivers/gpu/drm/exynos/exynos_drm_dsi.c | 82 +++++++++++++------------
>   1 file changed, 43 insertions(+), 39 deletions(-)
>
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> index d1039628b6f2..1450187c1edc 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> @@ -259,7 +259,7 @@ struct exynos_dsi_driver_data {
>   struct exynos_dsi {
>   	struct drm_encoder encoder;
>   	struct mipi_dsi_host dsi_host;
> -	struct list_head bridge_chain;
> +	struct drm_bridge bridge;
>   	struct drm_bridge *out_bridge;
>   	struct device *dev;
>   
> @@ -289,9 +289,9 @@ struct exynos_dsi {
>   
>   #define host_to_dsi(host) container_of(host, struct exynos_dsi, dsi_host)
>   
> -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 {
> @@ -882,9 +882,10 @@ static int exynos_dsi_init_link(struct exynos_dsi *dsi)
>   	return 0;
>   }
>   
> -static void exynos_dsi_set_display_mode(struct exynos_dsi *dsi)
> +static void exynos_dsi_set_display_mode(struct drm_bridge *bridge)
>   {
> -	struct drm_display_mode *m = &dsi->encoder.crtc->state->adjusted_mode;
> +	struct exynos_dsi *dsi = bridge_to_dsi(bridge);
> +	struct drm_display_mode *m = &bridge->encoder->crtc->state->adjusted_mode;
>   	unsigned int num_bits_resol = dsi->driver_data->num_bits_resol;
>   	u32 reg;
>   
> @@ -1376,10 +1377,10 @@ static void exynos_dsi_unregister_te_irq(struct exynos_dsi *dsi)
>   	}
>   }
>   
> -static void exynos_dsi_enable(struct drm_encoder *encoder)
> +static void exynos_dsi_enable(struct drm_bridge *bridge)
>   {
> -	struct exynos_dsi *dsi = encoder_to_dsi(encoder);
> -	struct drm_bridge *iter;
> +	struct exynos_dsi *dsi = bridge_to_dsi(bridge);
> +	const struct drm_bridge_funcs *funcs = dsi->out_bridge->funcs;


It will blow up in case there is no dsi->out_bridge, the same case in 
code below.

Beside this the conversion looks quite well, I hope tests will pass well :)


Regards

Andrzej



>   	int ret;
>   
>   	if (dsi->state & DSIM_STATE_ENABLED)
> @@ -1393,52 +1394,53 @@ static void exynos_dsi_enable(struct drm_encoder *encoder)
>   
>   	dsi->state |= DSIM_STATE_ENABLED;
>   
> -	list_for_each_entry_reverse(iter, &dsi->bridge_chain, chain_node) {
> -		if (iter->funcs->pre_enable)
> -			iter->funcs->pre_enable(iter);
> -	}
> +	if (dsi->out_bridge)
> +		funcs->pre_enable(dsi->out_bridge);
>   
> -	exynos_dsi_set_display_mode(dsi);
> +	exynos_dsi_set_display_mode(bridge);
>   	exynos_dsi_set_display_enable(dsi, true);
>   
> -	list_for_each_entry(iter, &dsi->bridge_chain, chain_node) {
> -		if (iter->funcs->enable)
> -			iter->funcs->enable(iter);
> -	}
> +	if (dsi->out_bridge)
> +		funcs->enable(dsi->out_bridge);
>   
>   	dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE;
>   	return;
>   }
>   
> -static void exynos_dsi_disable(struct drm_encoder *encoder)
> +static void exynos_dsi_disable(struct drm_bridge *bridge)
>   {
> -	struct exynos_dsi *dsi = encoder_to_dsi(encoder);
> -	struct drm_bridge *iter;
> +	struct exynos_dsi *dsi = bridge_to_dsi(bridge);
> +	const struct drm_bridge_funcs *funcs = dsi->out_bridge->funcs;
>   
>   	if (!(dsi->state & DSIM_STATE_ENABLED))
>   		return;
>   
>   	dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE;
>   
> -	list_for_each_entry_reverse(iter, &dsi->bridge_chain, chain_node) {
> -		if (iter->funcs->disable)
> -			iter->funcs->disable(iter);
> -	}
> +	if (dsi->out_bridge)
> +		funcs->disable(dsi->out_bridge);
>   
>   	exynos_dsi_set_display_enable(dsi, false);
>   
> -	list_for_each_entry(iter, &dsi->bridge_chain, chain_node) {
> -		if (iter->funcs->post_disable)
> -			iter->funcs->post_disable(iter);
> -	}
> +	if (dsi->out_bridge)
> +		funcs->post_disable(dsi->out_bridge);
>   
>   	dsi->state &= ~DSIM_STATE_ENABLED;
>   	pm_runtime_put_sync(dsi->dev);
>   }
>   
> -static const struct drm_encoder_helper_funcs exynos_dsi_encoder_helper_funcs = {
> -	.enable = exynos_dsi_enable,
> -	.disable = exynos_dsi_disable,
> +static int exynos_dsi_attach(struct drm_bridge *bridge,
> +			     enum drm_bridge_attach_flags flags)
> +{
> +	struct exynos_dsi *dsi = bridge_to_dsi(bridge);
> +
> +	return drm_bridge_attach(bridge->encoder, dsi->out_bridge, bridge, flags);
> +}
> +
> +static const struct drm_bridge_funcs exynos_dsi_bridge_funcs = {
> +	.enable				= exynos_dsi_enable,
> +	.disable			= exynos_dsi_disable,
> +	.attach				= exynos_dsi_attach,
>   };
>   
>   MODULE_DEVICE_TABLE(of, exynos_dsi_of_match);
> @@ -1460,8 +1462,9 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
>   
>   	DRM_DEV_INFO(dsi->dev, "Attached %s device\n", device->name);
>   
> -	drm_bridge_attach(encoder, dsi->out_bridge, NULL, 0);
> -	list_splice_init(&encoder->bridge_chain, &dsi->bridge_chain);
> +	drm_bridge_add(&dsi->bridge);
> +
> +	drm_bridge_attach(encoder, &dsi->bridge, NULL, 0);
>   
>   	/*
>   	 * This is a temporary solution and should be made by more generic way.
> @@ -1499,13 +1502,14 @@ static int exynos_dsi_host_detach(struct mipi_dsi_host *host,
>   
>   	if (dsi->out_bridge->funcs->detach)
>   		dsi->out_bridge->funcs->detach(dsi->out_bridge);
> -	INIT_LIST_HEAD(&dsi->bridge_chain);
>   
>   	if (drm->mode_config.poll_enabled)
>   		drm_kms_helper_hotplug_event(drm);
>   
>   	exynos_dsi_unregister_te_irq(dsi);
>   
> +	drm_bridge_remove(&dsi->bridge);
> +
>   	return 0;
>   }
>   
> @@ -1591,8 +1595,6 @@ 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;
> @@ -1612,9 +1614,8 @@ 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_disable(&dsi->bridge);
>   
>   	mipi_dsi_host_unregister(&dsi->dsi_host);
>   }
> @@ -1640,7 +1641,6 @@ static int exynos_dsi_probe(struct platform_device *pdev)
>   	init_completion(&dsi->completed);
>   	spin_lock_init(&dsi->transfer_lock);
>   	INIT_LIST_HEAD(&dsi->transfer_list);
> -	INIT_LIST_HEAD(&dsi->bridge_chain);
>   
>   	dsi->dsi_host.ops = &exynos_dsi_ops;
>   	dsi->dsi_host.dev = dev;
> @@ -1708,6 +1708,10 @@ 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;
> +
>   	ret = component_add(dev, &exynos_dsi_component_ops);
>   	if (ret)
>   		goto err_disable_runtime;