[PATCH 0/3] Simplify panel bridge cleanup

[PATCH 0/3] Simplify panel bridge cleanup

[Benjamin Gaignard]

The goal of this series is to simplify driver code when they need to clean up
a previously allocated panel bridge.
Few drivers have "is_panel_bridge" flag to be able to distinguish a
drm_panel_bridge from "simple" drm_bridge.
To remove this flag I propose to
- let drm_panel_bridge_remove() check if the bridge provided in parameter is
  really a drm_panel_bridge.
- add drm_of_panel_bridge_remove() to remove a bridge given DT port and
  endpoint
Finally that allow to remove drm_bridge structure and "is_panel_bridge" flag
from stm driver internal structure.

Benjamin Gaignard (3):
  drm/bridge: make drm_panel_bridge_remove more robust
  drm/drm_of: add drm_of_panel_bridge_remove function
  drm/stm: ltdc: remove bridge from driver internal structure

 drivers/gpu/drm/bridge/panel.c | 10 +++++++++-
 drivers/gpu/drm/drm_of.c       | 33 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/stm/ltdc.c     | 16 +++++-----------
 drivers/gpu/drm/stm/ltdc.h     |  2 --
 include/drm/drm_of.h           |  8 ++++++++
 5 files changed, 55 insertions(+), 14 deletions(-)

-- 
2.7.4

[PATCH 1/3] drm/bridge: make drm_panel_bridge_remove more robust

[Benjamin Gaignard]

Make sure that bridge parameter is not NULL and can be safely
cast into a panel_bridge structure.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
---
 drivers/gpu/drm/bridge/panel.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
index e0cca19..6d99d4a 100644
--- a/drivers/gpu/drm/bridge/panel.c
+++ b/drivers/gpu/drm/bridge/panel.c
@@ -188,7 +188,15 @@ EXPORT_SYMBOL(drm_panel_bridge_add);
  */
 void drm_panel_bridge_remove(struct drm_bridge *bridge)
 {
-	struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
+	struct panel_bridge *panel_bridge;
+
+	if (!bridge)
+		return;
+
+	if (bridge->funcs != &panel_bridge_bridge_funcs)
+		return;
+
+	panel_bridge = drm_bridge_to_panel_bridge(bridge);
 
 	drm_bridge_remove(bridge);
 	devm_kfree(panel_bridge->panel->dev, bridge);
-- 
2.7.4

[PATCH 2/3] drm/drm_of: add drm_of_panel_bridge_remove function

[Benjamin Gaignard]

This function is the pendant of drm_of_find_panel_or_bridge()
to remove a previously allocated panel_bridge.
Given a specific port and endpoint it remove the panel bridge.
Since drm_panel_bridge_remove() will check that bridge parameter
is not NULL and is a real drm_panel_bridge and no a simple bridge
it is safe to call it directly.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
---
 drivers/gpu/drm/drm_of.c | 33 +++++++++++++++++++++++++++++++++
 include/drm/drm_of.h     |  8 ++++++++
 2 files changed, 41 insertions(+)

diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
index 8dafbdf..6b54f17 100644
--- a/drivers/gpu/drm/drm_of.c
+++ b/drivers/gpu/drm/drm_of.c
@@ -260,3 +260,36 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
 	return ret;
 }
 EXPORT_SYMBOL_GPL(drm_of_find_panel_or_bridge);
+
+#ifdef CONFIG_DRM_PANEL_BRIDGE
+/*
+ * drm_of_panel_bridge_remove - remove panel bridge
+ * @np: device tree node containing panel bridge output ports
+ *
+ * Remove the panel bridge of a given DT node's port and endpoint number
+ *
+ * Returns zero if successful, or one of the standard error codes if it fails.
+ */
+int drm_of_panel_bridge_remove(const struct device_node *np,
+			       int port, int endpoint)
+{
+	struct drm_bridge *bridge;
+	struct device_node *remote;
+
+	remote = of_graph_get_remote_node(np, port, endpoint);
+	if (!remote)
+		return -ENODEV;
+
+	bridge = of_drm_find_bridge(remote);
+	drm_panel_bridge_remove(bridge);
+
+	return 0;
+}
+#else
+int drm_of_panel_bridge_remove(const struct device_node *np,
+			       int port, int endpoint)
+{
+	return -EINVAL;
+}
+#endif
+EXPORT_SYMBOL_GPL(drm_of_panel_bridge_remove);
diff --git a/include/drm/drm_of.h b/include/drm/drm_of.h
index 104dd51..390966e 100644
--- a/include/drm/drm_of.h
+++ b/include/drm/drm_of.h
@@ -29,6 +29,8 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
 				int port, int endpoint,
 				struct drm_panel **panel,
 				struct drm_bridge **bridge);
+int drm_of_panel_bridge_remove(const struct device_node *np,
+			       int port, int endpoint);
 #else
 static inline uint32_t drm_of_find_possible_crtcs(struct drm_device *dev,
 						  struct device_node *port)
@@ -65,6 +67,12 @@ static inline int drm_of_find_panel_or_bridge(const struct device_node *np,
 {
 	return -EINVAL;
 }
+
+static inline int drm_of_panel_bridge_remove(const struct device_node *np,
+					     int port, int endpoint)
+{
+	return -EINVAL;
+}
 #endif
 
 static inline int drm_of_encoder_active_endpoint_id(struct device_node *node,
-- 
2.7.4

[PATCH 3/3] drm/stm: ltdc: remove bridge from driver internal structure

[Benjamin Gaignard]

With a call to drm_of_panel_bridge_remove() we could remove the bridge
without store it in ldtc internal driver structure.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
---
 drivers/gpu/drm/stm/ltdc.c | 16 +++++-----------
 drivers/gpu/drm/stm/ltdc.h |  2 --
 2 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index d394a03..735c908 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -791,9 +791,8 @@ static const struct drm_encoder_funcs ltdc_encoder_funcs = {
 	.destroy = drm_encoder_cleanup,
 };
 
-static int ltdc_encoder_init(struct drm_device *ddev)
+static int ltdc_encoder_init(struct drm_device *ddev, struct drm_bridge *bridge)
 {
-	struct ltdc_device *ldev = ddev->dev_private;
 	struct drm_encoder *encoder;
 	int ret;
 
@@ -807,7 +806,7 @@ static int ltdc_encoder_init(struct drm_device *ddev)
 	drm_encoder_init(ddev, encoder, &ltdc_encoder_funcs,
 			 DRM_MODE_ENCODER_DPI, NULL);
 
-	ret = drm_bridge_attach(encoder, ldev->bridge, NULL);
+	ret = drm_bridge_attach(encoder, bridge, NULL);
 	if (ret) {
 		drm_encoder_cleanup(encoder);
 		return -EINVAL;
@@ -936,12 +935,9 @@ int ltdc_load(struct drm_device *ddev)
 			ret = PTR_ERR(bridge);
 			goto err;
 		}
-		ldev->is_panel_bridge = true;
 	}
 
-	ldev->bridge = bridge;
-
-	ret = ltdc_encoder_init(ddev);
+	ret = ltdc_encoder_init(ddev, bridge);
 	if (ret) {
 		DRM_ERROR("Failed to init encoder\n");
 		goto err;
@@ -972,8 +968,7 @@ int ltdc_load(struct drm_device *ddev)
 	return 0;
 
 err:
-	if (ldev->is_panel_bridge)
-		drm_panel_bridge_remove(bridge);
+	drm_panel_bridge_remove(bridge);
 
 	clk_disable_unprepare(ldev->pixel_clk);
 
@@ -986,8 +981,7 @@ void ltdc_unload(struct drm_device *ddev)
 
 	DRM_DEBUG_DRIVER("\n");
 
-	if (ldev->is_panel_bridge)
-		drm_panel_bridge_remove(ldev->bridge);
+	drm_of_panel_bridge_remove(ddev->dev->of_node, 0, 0);
 
 	clk_disable_unprepare(ldev->pixel_clk);
 }
diff --git a/drivers/gpu/drm/stm/ltdc.h b/drivers/gpu/drm/stm/ltdc.h
index bc6d6f6..ae43755 100644
--- a/drivers/gpu/drm/stm/ltdc.h
+++ b/drivers/gpu/drm/stm/ltdc.h
@@ -24,8 +24,6 @@ struct ltdc_device {
 	struct drm_fbdev_cma *fbdev;
 	void __iomem *regs;
 	struct clk *pixel_clk;	/* lcd pixel clock */
-	struct drm_bridge *bridge;
-	bool is_panel_bridge;
 	struct mutex err_lock;	/* protecting error_status */
 	struct ltdc_caps caps;
 	u32 error_status;
-- 
2.7.4

Re: [PATCH 0/3] Simplify panel bridge cleanup

[Philippe CORNU]

Hi Benjamin,
and many thanks for this cleanup patchset.

Reviewed-by: Philippe Cornu <philippe.cornu@st.com>
Tested-by: Philippe Cornu <philippe.cornu@st.com>

Philippe :-)

On 09/29/2017 02:59 PM, Benjamin Gaignard wrote:
> The goal of this series is to simplify driver code when they need to clean up
> a previously allocated panel bridge.
> Few drivers have "is_panel_bridge" flag to be able to distinguish a
> drm_panel_bridge from "simple" drm_bridge.
> To remove this flag I propose to
> - let drm_panel_bridge_remove() check if the bridge provided in parameter is
>    really a drm_panel_bridge.
> - add drm_of_panel_bridge_remove() to remove a bridge given DT port and
>    endpoint
> Finally that allow to remove drm_bridge structure and "is_panel_bridge" flag
> from stm driver internal structure.
> 
> Benjamin Gaignard (3):
>    drm/bridge: make drm_panel_bridge_remove more robust
>    drm/drm_of: add drm_of_panel_bridge_remove function
>    drm/stm: ltdc: remove bridge from driver internal structure
> 
>   drivers/gpu/drm/bridge/panel.c | 10 +++++++++-
>   drivers/gpu/drm/drm_of.c       | 33 +++++++++++++++++++++++++++++++++
>   drivers/gpu/drm/stm/ltdc.c     | 16 +++++-----------
>   drivers/gpu/drm/stm/ltdc.h     |  2 --
>   include/drm/drm_of.h           |  8 ++++++++
>   5 files changed, 55 insertions(+), 14 deletions(-)
> 

Re: [PATCH 0/3] Simplify panel bridge cleanup

[Daniel Vetter]

On Fri, Sep 29, 2017 at 03:03:54PM +0000, Philippe CORNU wrote:
> Hi Benjamin,
> and many thanks for this cleanup patchset.
> 
> Reviewed-by: Philippe Cornu <philippe.cornu@st.com>
> Tested-by: Philippe Cornu <philippe.cornu@st.com>

Can you pls either convert vc4 and dw-mipi too, or add an entry to our
todo list in Documentation/gpu/todo.rst?

Thanks, Daniel

> 
> Philippe :-)
> 
> On 09/29/2017 02:59 PM, Benjamin Gaignard wrote:
> > The goal of this series is to simplify driver code when they need to clean up
> > a previously allocated panel bridge.
> > Few drivers have "is_panel_bridge" flag to be able to distinguish a
> > drm_panel_bridge from "simple" drm_bridge.
> > To remove this flag I propose to
> > - let drm_panel_bridge_remove() check if the bridge provided in parameter is
> >    really a drm_panel_bridge.
> > - add drm_of_panel_bridge_remove() to remove a bridge given DT port and
> >    endpoint
> > Finally that allow to remove drm_bridge structure and "is_panel_bridge" flag
> > from stm driver internal structure.
> > 
> > Benjamin Gaignard (3):
> >    drm/bridge: make drm_panel_bridge_remove more robust
> >    drm/drm_of: add drm_of_panel_bridge_remove function
> >    drm/stm: ltdc: remove bridge from driver internal structure
> > 
> >   drivers/gpu/drm/bridge/panel.c | 10 +++++++++-
> >   drivers/gpu/drm/drm_of.c       | 33 +++++++++++++++++++++++++++++++++
> >   drivers/gpu/drm/stm/ltdc.c     | 16 +++++-----------
> >   drivers/gpu/drm/stm/ltdc.h     |  2 --
> >   include/drm/drm_of.h           |  8 ++++++++
> >   5 files changed, 55 insertions(+), 14 deletions(-)
> > 
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch