Re: [PATCH v1 1/3] drm/stm: ltdc: Add bridge support

[Eric Anholt]

Philippe CORNU  writes:

> Add the bridge support, used by DSI host and HDMI/LVDS bridges.
>
> Signed-off-by: Philippe CORNU 

> @@ -987,19 +1024,36 @@ static struct drm_panel *ltdc_get_panel(struct 
> drm_device *ddev)
>  
>   port = of_graph_get_remote_port_parent(entity);
>   if (port) {
> + struct drm_bridge *bridge;
> + struct drm_panel *panel;
> +
> + bridge = of_drm_find_bridge(port);
>   panel = of_drm_find_panel(port);
> - of_node_put(port);
> + if (!bridge && !panel) {
> + of_node_put(entity);
> + return -EPROBE_DEFER;
> + }
> +
> + if (bridge) {
> + if (!ldev->bridge) {
> + ldev->bridge = bridge;
> + DRM_INFO("remote bridge %s\n",
> +  port->full_name);
> + }
> + }
> +
>   if (panel) {
> - DRM_DEBUG_DRIVER("remote panel %s\n",
> + if (!ldev->panel) {
> + ldev->panel = panel;
> + DRM_INFO("remote panel %s\n",
>port->full_name);
> - } else {
> - DRM_DEBUG_DRIVER("panel missing\n");
> - of_node_put(entity);
> + }
>   }
> + of_node_put(port);

Is it possible to use drm_of_find_panel_or_bridge() instead?  I don't
think it makes sense to have both a bridge and a panel for the same
node, does it?


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[PATCH v1 1/3] drm/stm: ltdc: Add bridge support

[Philippe CORNU]

Add the bridge support, used by DSI host and HDMI/LVDS bridges.

Signed-off-by: Philippe CORNU 
---
 drivers/gpu/drm/stm/ltdc.c | 82 +++---
 drivers/gpu/drm/stm/ltdc.h |  1 +
 2 files changed, 72 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index 7b2d63b..b0d1fba 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -858,6 +858,43 @@ static struct drm_encoder *ltdc_rgb_encoder_create(struct 
drm_device *ddev)
return encoder;
 }
 
+static const struct drm_encoder_funcs bridge_encoder_funcs = {
+   .destroy = drm_encoder_cleanup,
+};
+
+struct drm_encoder *bridge_encoder_create(struct drm_device *ddev,
+ struct drm_bridge *bridge)
+{
+   struct drm_encoder *encoder;
+   int ret;
+
+   encoder = devm_kzalloc(ddev->dev, sizeof(*encoder), GFP_KERNEL);
+   if (!encoder)
+   return NULL;
+
+   encoder->possible_crtcs = CRTC_MASK;
+   encoder->possible_clones = 0; /* No cloning support */
+
+   drm_encoder_init(ddev, encoder, _encoder_funcs,
+DRM_MODE_ENCODER_TMDS, NULL);
+
+   drm_encoder_helper_add(encoder, NULL);
+
+   /* Link drm_bridge to encoder */
+   bridge->encoder = encoder;
+   encoder->bridge = bridge;
+
+   ret = drm_bridge_attach(encoder, bridge, NULL);
+   if (ret) {
+   drm_encoder_cleanup(encoder);
+   return NULL;
+   }
+
+   DRM_DEBUG_DRIVER("Bridge encoder:%d created\n", encoder->base.id);
+
+   return encoder;
+}
+
 /*
  * DRM_CONNECTOR
  */
@@ -967,12 +1004,12 @@ static int ltdc_get_caps(struct drm_device *ddev)
return 0;
 }
 
-static struct drm_panel *ltdc_get_panel(struct drm_device *ddev)
+static int ltdc_parse_dt(struct drm_device *ddev)
 {
+   struct ltdc_device *ldev = ddev->dev_private;
struct device *dev = ddev->dev;
struct device_node *np = dev->of_node;
struct device_node *entity, *port = NULL;
-   struct drm_panel *panel = NULL;
 
DRM_DEBUG_DRIVER("\n");
 
@@ -987,19 +1024,36 @@ static struct drm_panel *ltdc_get_panel(struct 
drm_device *ddev)
 
port = of_graph_get_remote_port_parent(entity);
if (port) {
+   struct drm_bridge *bridge;
+   struct drm_panel *panel;
+
+   bridge = of_drm_find_bridge(port);
panel = of_drm_find_panel(port);
-   of_node_put(port);
+   if (!bridge && !panel) {
+   of_node_put(entity);
+   return -EPROBE_DEFER;
+   }
+
+   if (bridge) {
+   if (!ldev->bridge) {
+   ldev->bridge = bridge;
+   DRM_INFO("remote bridge %s\n",
+port->full_name);
+   }
+   }
+
if (panel) {
-   DRM_DEBUG_DRIVER("remote panel %s\n",
+   if (!ldev->panel) {
+   ldev->panel = panel;
+   DRM_INFO("remote panel %s\n",
 port->full_name);
-   } else {
-   DRM_DEBUG_DRIVER("panel missing\n");
-   of_node_put(entity);
+   }
}
+   of_node_put(port);
}
}
 
-   return panel;
+   return 0;
 }
 
 int ltdc_load(struct drm_device *ddev)
@@ -1017,9 +1071,9 @@ int ltdc_load(struct drm_device *ddev)
 
DRM_DEBUG_DRIVER("\n");
 
-   ldev->panel = ltdc_get_panel(ddev);
-   if (!ldev->panel)
-   return -EPROBE_DEFER;
+   ret = ltdc_parse_dt(ddev);
+   if (ret)
+   return ret;
 
rstc = of_reset_control_get(np, NULL);
 
@@ -1077,6 +1131,12 @@ int ltdc_load(struct drm_device *ddev)
 
DRM_INFO("ltdc hw version 0x%08x - ready\n", ldev->caps.hw_version);
 
+   if (ldev->bridge) {
+   encoder = bridge_encoder_create(ddev, ldev->bridge);
+   if (!encoder)
+   return -EINVAL;
+   }
+
if (ldev->panel) {
encoder = ltdc_rgb_encoder_create(ddev);
if (!encoder) {
diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
index 5427ef4..0083cad 100644
--- a/drivers/gpu/drm/stm/ltdc.h
+++ b/drivers/gpu/drm/stm/ltdc.h
@@ -25,6 +25,7 @@ struct ltdc_device {
void __iomem *regs;
struct clk *pixel_clk;  /* lcd pixel clock */
struct drm_panel *panel;
+   struct