Patchwork [RFC,3/4] drm: tegra: use the Common Display Framework

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Submitter Alexandre Courbot
Date Jan. 30, 2013, 3:02 a.m.
Message ID <1359514939-15653-4-git-send-email-acourbot@nvidia.com>
Download mbox | patch
Permalink /patch/216757/
State Changes Requested, archived
Headers show

Comments

Alexandre Courbot - Jan. 30, 2013, 3:02 a.m.
Make the tegra-drm driver use the Common Display Framework, letting it
control the panel state according to the DPMS status.

A "nvidia,panel" property is added to the output node of the Tegra DC
that references the panel connected to a given output.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
 .../bindings/gpu/nvidia,tegra20-host1x.txt         |   2 +
 drivers/gpu/drm/tegra/drm.h                        |  16 +++
 drivers/gpu/drm/tegra/output.c                     | 118 ++++++++++++++++++++-
 3 files changed, 134 insertions(+), 2 deletions(-)
Mark Zhang - Jan. 30, 2013, 6:50 a.m.
On 01/30/2013 11:02 AM, Alexandre Courbot wrote:
> Make the tegra-drm driver use the Common Display Framework, letting it
> control the panel state according to the DPMS status.
> 
> A "nvidia,panel" property is added to the output node of the Tegra DC
> that references the panel connected to a given output.
> 
> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
> ---
[...]
> diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
> index 741b5dc..5e63c56 100644
> --- a/drivers/gpu/drm/tegra/drm.h
> +++ b/drivers/gpu/drm/tegra/drm.h
> @@ -17,6 +17,7 @@
>  #include <drm/drm_gem_cma_helper.h>
>  #include <drm/drm_fb_cma_helper.h>
>  #include <drm/drm_fixed.h>
> +#include <video/display.h>
>  
>  struct tegra_framebuffer {
>  	struct drm_framebuffer base;
> @@ -147,6 +148,9 @@ struct tegra_output {
>  
>  	struct drm_encoder encoder;
>  	struct drm_connector connector;
> +	struct display_entity this;
> +	struct display_entity *output;

Could you pick up a somewhat meaningful name? You know, there are too
many variables with name "drm/connector/output/encoder"... :)

> +	struct display_entity_notifier display_notifier;
>  };
>  
[...]
> +static int display_notify_callback(struct display_entity_notifier *notifier,
> +				   struct display_entity *entity, int event)
> +{
> +	struct tegra_output *output = display_notifier_to_output(notifier);
> +	struct device_node *pnode;
> +
> +	switch (event) {
> +	case DISPLAY_ENTITY_NOTIFIER_CONNECT:
> +		if (output->output)
> +			break;
> +
> +		pnode = of_parse_phandle(output->of_node, "nvidia,panel", 0);
> +		if (!pnode)
> +			break;
> +
> +		if (entity->dev && entity->dev->of_node == pnode) {
> +			dev_dbg(output->dev, "connecting panel\n");
> +			output->output = display_entity_get(entity);
> +			display_entity_connect(&output->this, output->output);
> +		}
> +		of_node_put(pnode);
> +
> +		break;
> +
> +	case DISPLAY_ENTITY_NOTIFIER_DISCONNECT:
> +		if (!output->output || output->output != entity)
> +			break;
> +
> +		dev_dbg(output->dev, "disconnecting panel\n");
> +		display_entity_disconnect(&output->this, output->output);
> +		output->output = NULL;
> +		display_entity_put(&output->this);

No "display_entity_get" for "output->this", so I don't think we need
"display_entity_put" here. If you register this entity with "release"
callback and you wanna release "output->this", call the "release"
function manually.

Only when you have "display_entity_get", use "display_entity_put" to
release.

> +
> +		break;
> +
> +	default:
> +		dev_dbg(output->dev, "unhandled display event\n");
> +		break;
> +	}
> +
> +	return 0;
> +}
> +
[...]
>  int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
>  {
>  	int connector, encoder, err;
> @@ -250,6 +341,23 @@ int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
>  
>  	output->encoder.possible_crtcs = 0x3;
>  
> +	/* register display entity */
> +	memset(&output->this, 0, sizeof(output->this));
> +	output->this.dev = drm->dev;

Use "output->dev" here. Actually the device you wanna register it to
display entity is the "encoder"(in drm terms), not "drm->dev". If we use
"drm->dev" here, we will have all same device for all encoders(HDMI,
DSI...).

> +	output->this.ops.video = &tegra_output_video_ops;
> +	err = display_entity_register(&output->this);
> +	if (err) {
> +		dev_err(output->dev, "cannot register display entity\n");
> +		return err;
> +	}
> +
> +	/* register display notifier */
> +	output->display_notifier.dev = NULL;

Set "display_notifier.dev" to NULL makes we have to compare with every
display entity, just like what you do in "display_notify_callback":

entity->dev && entity->dev->of_node == pnode

So can we get the "struct device *" of panel here? Seems currently the
"of" framework doesn't allow "device_node -> device".

> +	output->display_notifier.notify = display_notify_callback;
> +	err = display_entity_register_notifier(&output->display_notifier);
> +	if (err)
> +		return err;
> +
>  	return 0;
>  
>  free_hpd:
> @@ -260,6 +368,12 @@ free_hpd:
>  
>  int tegra_output_exit(struct tegra_output *output)
>  {
> +	if (output->output)
> +		display_entity_put(output->output);
> +
> +	display_entity_unregister_notifier(&output->display_notifier);
> +	display_entity_unregister(&output->this);
> +
>  	if (gpio_is_valid(output->hpd_gpio)) {
>  		free_irq(output->hpd_irq, output);
>  		gpio_free(output->hpd_gpio);
> 
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Alexandre Courbot - Jan. 30, 2013, 7:01 a.m.
On 01/30/2013 03:50 PM, Mark Zhang wrote:
>> @@ -147,6 +148,9 @@ struct tegra_output {
>>
>>   	struct drm_encoder encoder;
>>   	struct drm_connector connector;
>> +	struct display_entity this;
>> +	struct display_entity *output;
>
> Could you pick up a somewhat meaningful name? You know, there are too
> many variables with name "drm/connector/output/encoder"... :)

Well, it's supposed to be abstract. From the CDF point of view it could 
be anything besides a panel. I know this makes it an output of an 
output, but I can't think of anything better right now.

>> +		if (entity->dev && entity->dev->of_node == pnode) {
>> +			dev_dbg(output->dev, "connecting panel\n");
>> +			output->output = display_entity_get(entity);
>> +			display_entity_connect(&output->this, output->output);
>> +		}
>> +		of_node_put(pnode);
>> +
>> +		break;
>> +
>> +	case DISPLAY_ENTITY_NOTIFIER_DISCONNECT:
>> +		if (!output->output || output->output != entity)
>> +			break;
>> +
>> +		dev_dbg(output->dev, "disconnecting panel\n");
>> +		display_entity_disconnect(&output->this, output->output);
>> +		output->output = NULL;
>> +		display_entity_put(&output->this);
>
> No "display_entity_get" for "output->this", so I don't think we need
> "display_entity_put" here. If you register this entity with "release"
> callback and you wanna release "output->this", call the "release"
> function manually.

Oh, this was supposed to be called on output->output actually, to 
balance the display_entity_get() of the connect event. Thanks for 
catching this.

>> +	/* register display entity */
>> +	memset(&output->this, 0, sizeof(output->this));
>> +	output->this.dev = drm->dev;
>
> Use "output->dev" here. Actually the device you wanna register it to
> display entity is the "encoder"(in drm terms), not "drm->dev". If we use
> "drm->dev" here, we will have all same device for all encoders(HDMI,
> DSI...).

Yes, that's absolutely right.

>> +	/* register display notifier */
>> +	output->display_notifier.dev = NULL;
>
> Set "display_notifier.dev" to NULL makes we have to compare with every
> display entity, just like what you do in "display_notify_callback":
>
> entity->dev && entity->dev->of_node == pnode
>
> So can we get the "struct device *" of panel here? Seems currently the
> "of" framework doesn't allow "device_node -> device".

Nope. AFAICT the device might not be instanciated at this point. We 
become aware of it for the first time in the callback function. We also 
don't want to defer probing until the panel is parsed first, since the 
panel might also depend on resources of the display device.

Thanks,
Alex.

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Thierry Reding - Jan. 30, 2013, 7:24 a.m.
On Wed, Jan 30, 2013 at 04:01:48PM +0900, Alex Courbot wrote:
> On 01/30/2013 03:50 PM, Mark Zhang wrote:
> >>@@ -147,6 +148,9 @@ struct tegra_output {
> >>
> >>  	struct drm_encoder encoder;
> >>  	struct drm_connector connector;
> >>+	struct display_entity this;
> >>+	struct display_entity *output;
> >
> >Could you pick up a somewhat meaningful name? You know, there are too
> >many variables with name "drm/connector/output/encoder"... :)
> 
> Well, it's supposed to be abstract. From the CDF point of view it
> could be anything besides a panel. I know this makes it an output of
> an output, but I can't think of anything better right now.

How about renaming "this" to stream to match with what the output is in
CDF speak. And the output's output is the panel, right? Why not just
call it that? Even if it isn't directly connected to a panel entity but
has indeed a whole pipeline in between, for tegra-drm it is still a
panel.

Thierry
Alexandre Courbot - Jan. 30, 2013, 7:30 a.m.
On 01/30/2013 04:24 PM, Thierry Reding wrote:
>>> Could you pick up a somewhat meaningful name? You know, there are too
>>> many variables with name "drm/connector/output/encoder"... :)
>>
>> Well, it's supposed to be abstract. From the CDF point of view it
>> could be anything besides a panel. I know this makes it an output of
>> an output, but I can't think of anything better right now.
>
> How about renaming "this" to stream to match with what the output is in
> CDF speak.

Good idea.

> And the output's output is the panel, right? Why not just
> call it that? Even if it isn't directly connected to a panel entity but
> has indeed a whole pipeline in between, for tegra-drm it is still a
> panel.

Makes sense indeed. Besides the DT refer it as "panel" already.

Thanks,
Alex.
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Mark Zhang - Jan. 30, 2013, 7:46 a.m.
On 01/30/2013 03:01 PM, Alex Courbot wrote:
> On 01/30/2013 03:50 PM, Mark Zhang wrote:
[...]
> 
>>> +    /* register display notifier */
>>> +    output->display_notifier.dev = NULL;
>>
>> Set "display_notifier.dev" to NULL makes we have to compare with every
>> display entity, just like what you do in "display_notify_callback":
>>
>> entity->dev && entity->dev->of_node == pnode
>>
>> So can we get the "struct device *" of panel here? Seems currently the
>> "of" framework doesn't allow "device_node -> device".
> 
> Nope. AFAICT the device might not be instanciated at this point. We
> become aware of it for the first time in the callback function. We also
> don't want to defer probing until the panel is parsed first, since the
> panel might also depend on resources of the display device.
> 

Agree.

> Thanks,
> Alex.
> 
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Patch

diff --git a/Documentation/devicetree/bindings/gpu/nvidia,tegra20-host1x.txt b/Documentation/devicetree/bindings/gpu/nvidia,tegra20-host1x.txt
index b4fa934..9c65e8e 100644
--- a/Documentation/devicetree/bindings/gpu/nvidia,tegra20-host1x.txt
+++ b/Documentation/devicetree/bindings/gpu/nvidia,tegra20-host1x.txt
@@ -67,6 +67,7 @@  of the following host1x client modules:
   - nvidia,ddc-i2c-bus: phandle of an I2C controller used for DDC EDID probing
   - nvidia,hpd-gpio: specifies a GPIO used for hotplug detection
   - nvidia,edid: supplies a binary EDID blob
+  - nvidia,panel: phandle of a display entity connected to this output
 
 - hdmi: High Definition Multimedia Interface
 
@@ -81,6 +82,7 @@  of the following host1x client modules:
   - nvidia,ddc-i2c-bus: phandle of an I2C controller used for DDC EDID probing
   - nvidia,hpd-gpio: specifies a GPIO used for hotplug detection
   - nvidia,edid: supplies a binary EDID blob
+  - nvidia,panel: phandle of a display entity connected to this output
 
 - tvo: TV encoder output
 
diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index 741b5dc..5e63c56 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -17,6 +17,7 @@ 
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_fixed.h>
+#include <video/display.h>
 
 struct tegra_framebuffer {
 	struct drm_framebuffer base;
@@ -147,6 +148,9 @@  struct tegra_output {
 
 	struct drm_encoder encoder;
 	struct drm_connector connector;
+	struct display_entity this;
+	struct display_entity *output;
+	struct display_entity_notifier display_notifier;
 };
 
 static inline struct tegra_output *encoder_to_output(struct drm_encoder *e)
@@ -159,6 +163,18 @@  static inline struct tegra_output *connector_to_output(struct drm_connector *c)
 	return container_of(c, struct tegra_output, connector);
 }
 
+static inline
+struct tegra_output *display_entity_to_output(struct display_entity *e)
+{
+	return container_of(e, struct tegra_output, this);
+}
+
+static inline struct tegra_output *
+display_notifier_to_output(struct display_entity_notifier *n)
+{
+	return container_of(n, struct tegra_output, display_notifier);
+}
+
 static inline int tegra_output_enable(struct tegra_output *output)
 {
 	if (output && output->ops && output->ops->enable)
diff --git a/drivers/gpu/drm/tegra/output.c b/drivers/gpu/drm/tegra/output.c
index 8140fc6..d5bf37a 100644
--- a/drivers/gpu/drm/tegra/output.c
+++ b/drivers/gpu/drm/tegra/output.c
@@ -105,6 +105,29 @@  static const struct drm_encoder_funcs encoder_funcs = {
 
 static void tegra_encoder_dpms(struct drm_encoder *encoder, int mode)
 {
+	struct tegra_output *output = encoder_to_output(encoder);
+	enum display_entity_state state;
+
+	if (!output->output)
+		return;
+
+	switch (mode) {
+	case DRM_MODE_DPMS_ON:
+		state = DISPLAY_ENTITY_STATE_ON;
+		break;
+	case DRM_MODE_DPMS_STANDBY:
+	case DRM_MODE_DPMS_SUSPEND:
+		state = DISPLAY_ENTITY_STATE_STANDBY;
+		break;
+	case DRM_MODE_DPMS_OFF:
+		state = DISPLAY_ENTITY_STATE_OFF;
+		break;
+	default:
+		dev_warn(output->dev, "unknown DPMS state, ignoring\n");
+		return;
+	}
+
+	display_entity_set_state(output->output, state);
 }
 
 static bool tegra_encoder_mode_fixup(struct drm_encoder *encoder,
@@ -129,9 +152,14 @@  static void tegra_encoder_mode_set(struct drm_encoder *encoder,
 	struct tegra_output *output = encoder_to_output(encoder);
 	int err;
 
-	err = tegra_output_enable(output);
+	if (output->output)
+		err = display_entity_set_state(output->output,
+					       DISPLAY_ENTITY_STATE_ON);
+	else
+		err = tegra_output_enable(output);
+
 	if (err < 0)
-		dev_err(encoder->dev->dev, "tegra_output_enable(): %d\n", err);
+		dev_err(encoder->dev->dev, "cannot enable output: %d\n", err);
 }
 
 static const struct drm_encoder_helper_funcs encoder_helper_funcs = {
@@ -185,6 +213,69 @@  int tegra_output_parse_dt(struct tegra_output *output)
 	return 0;
 }
 
+static int display_notify_callback(struct display_entity_notifier *notifier,
+				   struct display_entity *entity, int event)
+{
+	struct tegra_output *output = display_notifier_to_output(notifier);
+	struct device_node *pnode;
+
+	switch (event) {
+	case DISPLAY_ENTITY_NOTIFIER_CONNECT:
+		if (output->output)
+			break;
+
+		pnode = of_parse_phandle(output->of_node, "nvidia,panel", 0);
+		if (!pnode)
+			break;
+
+		if (entity->dev && entity->dev->of_node == pnode) {
+			dev_dbg(output->dev, "connecting panel\n");
+			output->output = display_entity_get(entity);
+			display_entity_connect(&output->this, output->output);
+		}
+		of_node_put(pnode);
+
+		break;
+
+	case DISPLAY_ENTITY_NOTIFIER_DISCONNECT:
+		if (!output->output || output->output != entity)
+			break;
+
+		dev_dbg(output->dev, "disconnecting panel\n");
+		display_entity_disconnect(&output->this, output->output);
+		output->output = NULL;
+		display_entity_put(&output->this);
+
+		break;
+
+	default:
+		dev_dbg(output->dev, "unhandled display event\n");
+		break;
+	}
+
+	return 0;
+}
+
+static int tegra_output_set_stream(struct display_entity *entity,
+				   enum display_entity_stream_state state)
+{
+	struct tegra_output *output = display_entity_to_output(entity);
+
+	switch (state) {
+	case DISPLAY_ENTITY_STATE_OFF:
+	case DISPLAY_ENTITY_STATE_STANDBY:
+		return output->ops->disable(output);
+	case DISPLAY_ENTITY_STATE_ON:
+		return output->ops->enable(output);
+	}
+
+	return 0;
+}
+
+static struct display_entity_video_ops tegra_output_video_ops = {
+	.set_stream = tegra_output_set_stream,
+};
+
 int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
 {
 	int connector, encoder, err;
@@ -250,6 +341,23 @@  int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
 
 	output->encoder.possible_crtcs = 0x3;
 
+	/* register display entity */
+	memset(&output->this, 0, sizeof(output->this));
+	output->this.dev = drm->dev;
+	output->this.ops.video = &tegra_output_video_ops;
+	err = display_entity_register(&output->this);
+	if (err) {
+		dev_err(output->dev, "cannot register display entity\n");
+		return err;
+	}
+
+	/* register display notifier */
+	output->display_notifier.dev = NULL;
+	output->display_notifier.notify = display_notify_callback;
+	err = display_entity_register_notifier(&output->display_notifier);
+	if (err)
+		return err;
+
 	return 0;
 
 free_hpd:
@@ -260,6 +368,12 @@  free_hpd:
 
 int tegra_output_exit(struct tegra_output *output)
 {
+	if (output->output)
+		display_entity_put(output->output);
+
+	display_entity_unregister_notifier(&output->display_notifier);
+	display_entity_unregister(&output->this);
+
 	if (gpio_is_valid(output->hpd_gpio)) {
 		free_irq(output->hpd_irq, output);
 		gpio_free(output->hpd_gpio);