Re: [PATCH v4 08/15] drm/bridge: parade-ps8622: add drm_panel_bridge support

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sam,

Thank you for the patch.

On Sun, Jul 26, 2020 at 10:33:17PM +0200, Sam Ravnborg wrote:
> Prepare the bridge driver for use in a chained setup by
> replacing direct use of drm_panel with drm_panel_bridge support.
> 
> The connecter is now either created by the panel bridge or the display
> driver. So all code for connector creation in this driver is no longer
> relevant and thus dropped.
> 
> The connector code had some special polling handling:
>     connector.polled = DRM_CONNECTOR_POLL_HPD;
>     drm_helper_hpd_irq_event(ps8622->bridge.dev);
> 
> This code was most likely added to speed up detection of the connector.
> If really needed then this functionality belongs somewhere else.
> 
> Note: the bridge panel will use the connector type from the panel.
> 
> v2:
>   - Fix to avoid creating connector twice (Laurent)
>   - Drop all connector code - defer to bridge panel
>   - Use panel_bridge for local variable to align with other drivers
>   - Set bridge.type to DRM_MODE_CONNECTOR_LVDS;
> 
> Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
> Cc: Andrzej Hajda <a.hajda@samsung.com>
> Cc: Neil Armstrong <narmstrong@baylibre.com>
> Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com>
> Cc: Jonas Karlman <jonas@kwiboo.se>
> Cc: Jernej Skrabec <jernej.skrabec@siol.net>
> ---
>  drivers/gpu/drm/bridge/parade-ps8622.c | 100 ++++---------------------
>  1 file changed, 13 insertions(+), 87 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/parade-ps8622.c b/drivers/gpu/drm/bridge/parade-ps8622.c
> index d789ea2a7fb9..614b19f0f1b7 100644
> --- a/drivers/gpu/drm/bridge/parade-ps8622.c
> +++ b/drivers/gpu/drm/bridge/parade-ps8622.c
> @@ -42,10 +42,9 @@
>  #endif
>  
>  struct ps8622_bridge {
> -	struct drm_connector connector;
>  	struct i2c_client *client;
>  	struct drm_bridge bridge;
> -	struct drm_panel *panel;
> +	struct drm_bridge *panel_bridge;
>  	struct regulator *v12;
>  	struct backlight_device *bl;
>  
> @@ -64,12 +63,6 @@ static inline struct ps8622_bridge *
>  	return container_of(bridge, struct ps8622_bridge, bridge);
>  }
>  
> -static inline struct ps8622_bridge *
> -		connector_to_ps8622(struct drm_connector *connector)
> -{
> -	return container_of(connector, struct ps8622_bridge, connector);
> -}
> -
>  static int ps8622_set(struct i2c_client *client, u8 page, u8 reg, u8 val)
>  {
>  	int ret;
> @@ -365,11 +358,6 @@ static void ps8622_pre_enable(struct drm_bridge *bridge)
>  			DRM_ERROR("fails to enable ps8622->v12");
>  	}
>  
> -	if (drm_panel_prepare(ps8622->panel)) {
> -		DRM_ERROR("failed to prepare panel\n");
> -		return;
> -	}
> -
>  	gpiod_set_value(ps8622->gpio_slp, 1);
>  
>  	/*
> @@ -399,24 +387,9 @@ static void ps8622_pre_enable(struct drm_bridge *bridge)
>  	ps8622->enabled = true;
>  }
>  
> -static void ps8622_enable(struct drm_bridge *bridge)
> -{
> -	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
> -
> -	if (drm_panel_enable(ps8622->panel)) {
> -		DRM_ERROR("failed to enable panel\n");
> -		return;
> -	}
> -}
> -
>  static void ps8622_disable(struct drm_bridge *bridge)
>  {
> -	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
> -
> -	if (drm_panel_disable(ps8622->panel)) {
> -		DRM_ERROR("failed to disable panel\n");
> -		return;
> -	}
> +	/* Delay after panel is disabled */
>  	msleep(PS8622_PWMO_END_T12_MS);

I really don't understand why a delay would be needed here.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

>  }
>  
> @@ -436,11 +409,6 @@ static void ps8622_post_disable(struct drm_bridge *bridge)
>  	 */
>  	gpiod_set_value(ps8622->gpio_slp, 0);
>  
> -	if (drm_panel_unprepare(ps8622->panel)) {
> -		DRM_ERROR("failed to unprepare panel\n");
> -		return;
> -	}
> -
>  	if (ps8622->v12)
>  		regulator_disable(ps8622->v12);
>  
> @@ -455,67 +423,17 @@ static void ps8622_post_disable(struct drm_bridge *bridge)
>  	msleep(PS8622_POWER_OFF_T17_MS);
>  }
>  
> -static int ps8622_get_modes(struct drm_connector *connector)
> -{
> -	struct ps8622_bridge *ps8622;
> -
> -	ps8622 = connector_to_ps8622(connector);
> -
> -	return drm_panel_get_modes(ps8622->panel, connector);
> -}
> -
> -static const struct drm_connector_helper_funcs ps8622_connector_helper_funcs = {
> -	.get_modes = ps8622_get_modes,
> -};
> -
> -static const struct drm_connector_funcs ps8622_connector_funcs = {
> -	.fill_modes = drm_helper_probe_single_connector_modes,
> -	.destroy = drm_connector_cleanup,
> -	.reset = drm_atomic_helper_connector_reset,
> -	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> -	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> -};
> -
>  static int ps8622_attach(struct drm_bridge *bridge,
>  			 enum drm_bridge_attach_flags flags)
>  {
>  	struct ps8622_bridge *ps8622 = bridge_to_ps8622(bridge);
> -	int ret;
> -
> -	if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) {
> -		DRM_ERROR("Fix bridge driver to make connector optional!");
> -		return -EINVAL;
> -	}
>  
> -	if (!bridge->encoder) {
> -		DRM_ERROR("Parent encoder object not found");
> -		return -ENODEV;
> -	}
> -
> -	ps8622->connector.polled = DRM_CONNECTOR_POLL_HPD;
> -	ret = drm_connector_init(bridge->dev, &ps8622->connector,
> -			&ps8622_connector_funcs, DRM_MODE_CONNECTOR_LVDS);
> -	if (ret) {
> -		DRM_ERROR("Failed to initialize connector with drm\n");
> -		return ret;
> -	}
> -	drm_connector_helper_add(&ps8622->connector,
> -					&ps8622_connector_helper_funcs);
> -	drm_connector_register(&ps8622->connector);
> -	drm_connector_attach_encoder(&ps8622->connector,
> -							bridge->encoder);
> -
> -	if (ps8622->panel)
> -		drm_panel_attach(ps8622->panel, &ps8622->connector);
> -
> -	drm_helper_hpd_irq_event(ps8622->connector.dev);
> -
> -	return ret;
> +	return drm_bridge_attach(ps8622->bridge.encoder, ps8622->panel_bridge,
> +				 &ps8622->bridge, flags);
>  }
>  
>  static const struct drm_bridge_funcs ps8622_bridge_funcs = {
>  	.pre_enable = ps8622_pre_enable,
> -	.enable = ps8622_enable,
>  	.disable = ps8622_disable,
>  	.post_disable = ps8622_post_disable,
>  	.attach = ps8622_attach,
> @@ -533,16 +451,23 @@ static int ps8622_probe(struct i2c_client *client,
>  {
>  	struct device *dev = &client->dev;
>  	struct ps8622_bridge *ps8622;
> +	struct drm_bridge *panel_bridge;
> +	struct drm_panel *panel;
>  	int ret;
>  
>  	ps8622 = devm_kzalloc(dev, sizeof(*ps8622), GFP_KERNEL);
>  	if (!ps8622)
>  		return -ENOMEM;
>  
> -	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &ps8622->panel, NULL);
> +	ret = drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &panel, NULL);
>  	if (ret)
>  		return ret;
>  
> +	panel_bridge = devm_drm_panel_bridge_add(dev, panel);
> +	if (IS_ERR(panel_bridge))
> +		return PTR_ERR(panel_bridge);
> +
> +	ps8622->panel_bridge = panel_bridge;
>  	ps8622->client = client;
>  
>  	ps8622->v12 = devm_regulator_get(dev, "vdd12");
> @@ -595,6 +520,7 @@ static int ps8622_probe(struct i2c_client *client,
>  	}
>  
>  	ps8622->bridge.funcs = &ps8622_bridge_funcs;
> +	ps8622->bridge.type = DRM_MODE_CONNECTOR_LVDS;
>  	ps8622->bridge.of_node = dev->of_node;
>  	drm_bridge_add(&ps8622->bridge);
>  

-- 
Regards,

Laurent Pinchart
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