Re: [PATCH v2 5/7] drm/ltdc: Use the panel-bridge helper.

[Boris Brezillon]

Hi Philippe,

Le Tue, 30 May 2017 16:55:42 +0000,
Philippe CORNU <philippe.cornu@xxxxxx> a Ãcrit :

> Hi Eric,
> 
> I took your patch for the panel-bridge and it works perfectly in both 
> DPI mode (panel RGB //) and DSI mode (bridge dw mipi dsi), bravo :-)

I still don't understand how it can work without a call to
drm_bridge_attach() (which is used to link the RGB encoder to the DPI
connector). I'm probably missing something obvious. Maybe someone can
point it out :-).

Thanks,

Boris

> 
> ~160 lines have been removed from ltdc.c thanks to your panel-bridge code!
> 
> Many thanks
> Philippe
> 
> On 05/11/2017 08:31 PM, Eric Anholt wrote:
> > Another 100 lines of boilerplate gone.  Bridges aren't supported yet,
> > but will be trivial to add later.
> > 
> > Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
> > ---
> > 
> > Also untested.
> > 
> >   drivers/gpu/drm/stm/ltdc.c | 128 +++++----------------------------------------
> >   drivers/gpu/drm/stm/ltdc.h |   2 +-
> >   2 files changed, 13 insertions(+), 117 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
> > index a40418cda74a..41a1c5d68f5b 100644
> > --- a/drivers/gpu/drm/stm/ltdc.c
> > +++ b/drivers/gpu/drm/stm/ltdc.c
> > @@ -269,11 +269,6 @@ static inline struct ltdc_device *encoder_to_ltdc(struct drm_encoder *enc)
> >   	return (struct ltdc_device *)enc->dev->dev_private;
> >   }
> >   
> > -static inline struct ltdc_device *connector_to_ltdc(struct drm_connector *con)
> > -{
> > -	return (struct ltdc_device *)con->dev->dev_private;
> > -}
> > -
> >   static inline enum ltdc_pix_fmt to_ltdc_pixelformat(u32 drm_fmt)
> >   {
> >   	enum ltdc_pix_fmt pf;
> > @@ -815,22 +810,12 @@ static int ltdc_crtc_init(struct drm_device *ddev, struct drm_crtc *crtc)
> >   
> >   static void ltdc_rgb_encoder_enable(struct drm_encoder *encoder)
> >   {
> > -	struct ltdc_device *ldev = encoder_to_ltdc(encoder);
> > -
> >   	DRM_DEBUG_DRIVER("\n");
> > -
> > -	drm_panel_prepare(ldev->panel);
> > -	drm_panel_enable(ldev->panel);
> >   }
> >   
> >   static void ltdc_rgb_encoder_disable(struct drm_encoder *encoder)
> >   {
> > -	struct ltdc_device *ldev = encoder_to_ltdc(encoder);
> > -
> >   	DRM_DEBUG_DRIVER("\n");
> > -
> > -	drm_panel_disable(ldev->panel);
> > -	drm_panel_unprepare(ldev->panel);
> >   }
> >   
> >   static const struct drm_encoder_helper_funcs ltdc_rgb_encoder_helper_funcs = {
> > @@ -863,82 +848,6 @@ static struct drm_encoder *ltdc_rgb_encoder_create(struct drm_device *ddev)
> >   	return encoder;
> >   }
> >   
> > -/*
> > - * DRM_CONNECTOR
> > - */
> > -
> > -static int ltdc_rgb_connector_get_modes(struct drm_connector *connector)
> > -{
> > -	struct drm_device *ddev = connector->dev;
> > -	struct ltdc_device *ldev = ddev->dev_private;
> > -	int ret = 0;
> > -
> > -	DRM_DEBUG_DRIVER("\n");
> > -
> > -	if (ldev->panel)
> > -		ret = drm_panel_get_modes(ldev->panel);
> > -
> > -	return ret < 0 ? 0 : ret;
> > -}
> > -
> > -static struct drm_connector_helper_funcs ltdc_rgb_connector_helper_funcs = {
> > -	.get_modes = ltdc_rgb_connector_get_modes,
> > -};
> > -
> > -static enum drm_connector_status
> > -ltdc_rgb_connector_detect(struct drm_connector *connector, bool force)
> > -{
> > -	struct ltdc_device *ldev = connector_to_ltdc(connector);
> > -
> > -	return ldev->panel ? connector_status_connected :
> > -	       connector_status_disconnected;
> > -}
> > -
> > -static void ltdc_rgb_connector_destroy(struct drm_connector *connector)
> > -{
> > -	DRM_DEBUG_DRIVER("\n");
> > -
> > -	drm_connector_unregister(connector);
> > -	drm_connector_cleanup(connector);
> > -}
> > -
> > -static const struct drm_connector_funcs ltdc_rgb_connector_funcs = {
> > -	.dpms = drm_atomic_helper_connector_dpms,
> > -	.fill_modes = drm_helper_probe_single_connector_modes,
> > -	.detect = ltdc_rgb_connector_detect,
> > -	.destroy = ltdc_rgb_connector_destroy,
> > -	.reset = drm_atomic_helper_connector_reset,
> > -	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> > -	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> > -};
> > -
> > -struct drm_connector *ltdc_rgb_connector_create(struct drm_device *ddev)
> > -{
> > -	struct drm_connector *connector;
> > -	int err;
> > -
> > -	connector = devm_kzalloc(ddev->dev, sizeof(*connector), GFP_KERNEL);
> > -	if (!connector) {
> > -		DRM_ERROR("Failed to allocate connector\n");
> > -		return NULL;
> > -	}
> > -
> > -	connector->polled = DRM_CONNECTOR_POLL_HPD;
> > -
> > -	err = drm_connector_init(ddev, connector, &ltdc_rgb_connector_funcs,
> > -				 DRM_MODE_CONNECTOR_DPI);
> > -	if (err) {
> > -		DRM_ERROR("Failed to initialize connector\n");
> > -		return NULL;
> > -	}
> > -
> > -	drm_connector_helper_add(connector, &ltdc_rgb_connector_helper_funcs);
> > -
> > -	DRM_DEBUG_DRIVER("RGB connector:%d created\n", connector->base.id);
> > -
> > -	return connector;
> > -}
> > -
> >   static int ltdc_get_caps(struct drm_device *ddev)
> >   {
> >   	struct ltdc_device *ldev = ddev->dev_private;
> > @@ -972,7 +881,7 @@ static int ltdc_get_caps(struct drm_device *ddev)
> >   	return 0;
> >   }
> >   
> > -static struct drm_panel *ltdc_get_panel(struct drm_device *ddev)
> > +static struct drm_bridge *ltdc_get_bridge(struct drm_device *ddev)
> >   {
> >   	struct device *dev = ddev->dev;
> >   	struct device_node *np = dev->of_node;
> > @@ -1004,7 +913,10 @@ static struct drm_panel *ltdc_get_panel(struct drm_device *ddev)
> >   		}
> >   	}
> >   
> > -	return panel;
> > +	if (!panel)
> > +		return ERR_PTR(-ENODEV);
> > +
> > +	return drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_DPI);
> >   }
> >   
> >   int ltdc_load(struct drm_device *ddev)
> > @@ -1014,7 +926,6 @@ int ltdc_load(struct drm_device *ddev)
> >   	struct device *dev = ddev->dev;
> >   	struct device_node *np = dev->of_node;
> >   	struct drm_encoder *encoder;
> > -	struct drm_connector *connector = NULL;
> >   	struct drm_crtc *crtc;
> >   	struct reset_control *rstc;
> >   	struct resource res;
> > @@ -1022,8 +933,8 @@ int ltdc_load(struct drm_device *ddev)
> >   
> >   	DRM_DEBUG_DRIVER("\n");
> >   
> > -	ldev->panel = ltdc_get_panel(ddev);
> > -	if (!ldev->panel)
> > +	ldev->bridge = ltdc_get_bridge(ddev);
> > +	if (!ldev->bridge)
> >   		return -EPROBE_DEFER;
> >   
> >   	rstc = of_reset_control_get(np, NULL);
> > @@ -1082,28 +993,13 @@ int ltdc_load(struct drm_device *ddev)
> >   
> >   	DRM_INFO("ltdc hw version 0x%08x - ready\n", ldev->caps.hw_version);
> >   
> > -	if (ldev->panel) {
> > +	if (ldev->bridge) {
> >   		encoder = ltdc_rgb_encoder_create(ddev);
> >   		if (!encoder) {
> >   			DRM_ERROR("Failed to create RGB encoder\n");
> >   			ret = -EINVAL;
> >   			goto err;
> >   		}
> > -
> > -		connector = ltdc_rgb_connector_create(ddev);
> > -		if (!connector) {
> > -			DRM_ERROR("Failed to create RGB connector\n");
> > -			ret = -EINVAL;
> > -			goto err;
> > -		}
> > -
> > -		ret = drm_mode_connector_attach_encoder(connector, encoder);
> > -		if (ret) {
> > -			DRM_ERROR("Failed to attach connector to encoder\n");
> > -			goto err;
> > -		}
> > -
> > -		drm_panel_attach(ldev->panel, connector);
> >   	}
> >   
> >   	crtc = devm_kzalloc(dev, sizeof(*crtc), GFP_KERNEL);
> > @@ -1130,8 +1026,8 @@ int ltdc_load(struct drm_device *ddev)
> >   
> >   	return 0;
> >   err:
> > -	if (ldev->panel)
> > -		drm_panel_detach(ldev->panel);
> > +	if (ldev->bridge)
> > +		drm_panel_bridge_remove(ldev->bridge);
> >   
> >   	clk_disable_unprepare(ldev->pixel_clk);
> >   
> > @@ -1146,8 +1042,8 @@ void ltdc_unload(struct drm_device *ddev)
> >   
> >   	drm_vblank_cleanup(ddev);
> >   
> > -	if (ldev->panel)
> > -		drm_panel_detach(ldev->panel);
> > +	if (ldev->bridge)
> > +		drm_panel_bridge_remove(ldev->bridge);
> >   
> >   	clk_disable_unprepare(ldev->pixel_clk);
> >   }
> > diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
> > index d7a9c736ac1e..d78cb0dd3200 100644
> > --- a/drivers/gpu/drm/stm/ltdc.h
> > +++ b/drivers/gpu/drm/stm/ltdc.h
> > @@ -24,7 +24,7 @@ struct ltdc_device {
> >   	struct drm_fbdev_cma *fbdev;
> >   	void __iomem *regs;
> >   	struct clk *pixel_clk;	/* lcd pixel clock */
> > -	struct drm_panel *panel;
> > +	struct drm_bridge *bridge;
> >   	struct mutex err_lock;	/* protecting error_status */
> >   	struct ltdc_caps caps;
> >   	u32 clut[256];		/* color look up table */
> >