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

Archit Taneja <architt@xxxxxxxxxxxxxx> · Wed, 31 May 2017 13:31:16 +0530

Hi Boris,

On 05/31/2017 11:56 AM, Boris Brezillon wrote:
Hi Philippe,

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

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 :-).

I think the expectation is that there will be a follow-up patch that
would add bridge support. Philippe had posted a patch for adding bridges
to ltdc before:

https://patchwork.kernel.org/patch/9724835/

He can now redo his patch over Eric's panel-bridge patch-set.

Thanks,
Archit


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 */



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