[v4] Add a panel API to return panel orientation

[PATCH v4 1/8] drm/panel: Add an API drm_panel_get_orientation() to return panel orientation

Posted by Hsin-Yi Wang 3 years, 8 months ago

Panels usually call drm_connector_set_panel_orientation(), which is
later than drm/kms driver calling drm_dev_register(). This leads to a
WARN().

The orientation property is known earlier. For example, some panels
parse the property through device tree during probe.

Add an API to return the property from panel to drm/kms driver, so the
drivers are able to call drm_connector_set_panel_orientation() before
drm_dev_register().

Suggested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
---
v3->v4: Add a blank line.
---
 drivers/gpu/drm/drm_panel.c |  9 +++++++++
 include/drm/drm_panel.h     | 10 ++++++++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index f634371c717a..e12056cfeca8 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -223,6 +223,15 @@ int drm_panel_get_modes(struct drm_panel *panel,
 }
 EXPORT_SYMBOL(drm_panel_get_modes);
 
+enum drm_panel_orientation drm_panel_get_orientation(struct drm_panel *panel)
+{
+	if (panel && panel->funcs && panel->funcs->get_orientation)
+		return panel->funcs->get_orientation(panel);
+
+	return DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
+}
+EXPORT_SYMBOL(drm_panel_get_orientation);
+
 #ifdef CONFIG_OF
 /**
  * of_drm_find_panel - look up a panel using a device tree node
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index d279ee455f01..5dadbf3b0370 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -133,6 +133,15 @@ struct drm_panel_funcs {
 	 * Allows panels to create panels-specific debugfs files.
 	 */
 	void (*debugfs_init)(struct drm_panel *panel, struct dentry *root);
+
+	/**
+	 * @get_orientation:
+	 *
+	 * Return the panel orientation set by device tree or EDID.
+	 *
+	 * This function is optional.
+	 */
+	enum drm_panel_orientation (*get_orientation)(struct drm_panel *panel);
 };
 
 /**
@@ -202,6 +211,7 @@ int drm_panel_enable(struct drm_panel *panel);
 int drm_panel_disable(struct drm_panel *panel);
 
 int drm_panel_get_modes(struct drm_panel *panel, struct drm_connector *connector);
+enum drm_panel_orientation drm_panel_get_orientation(struct drm_panel *panel);
 
 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
 struct drm_panel *of_drm_find_panel(const struct device_node *np);
-- 
2.36.1.255.ge46751e96f-goog

Re: [PATCH v4 1/8] drm/panel: Add an API drm_panel_get_orientation() to return panel orientation

Posted by Sam Ravnborg 3 years, 8 months ago

Hi Hsin-Yi,
On Mon, Jun 06, 2022 at 11:24:24PM +0800, Hsin-Yi Wang wrote:
> Panels usually call drm_connector_set_panel_orientation(), which is
> later than drm/kms driver calling drm_dev_register(). This leads to a
> WARN().
> 
> The orientation property is known earlier. For example, some panels
> parse the property through device tree during probe.
> 
> Add an API to return the property from panel to drm/kms driver, so the
> drivers are able to call drm_connector_set_panel_orientation() before
> drm_dev_register().
> 
> Suggested-by: Hans de Goede <hdegoede@redhat.com>
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
> Reviewed-by: Hans de Goede <hdegoede@redhat.com>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>
> ---
> v3->v4: Add a blank line.
> ---
>  drivers/gpu/drm/drm_panel.c |  9 +++++++++
>  include/drm/drm_panel.h     | 10 ++++++++++
>  2 files changed, 19 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
> index f634371c717a..e12056cfeca8 100644
> --- a/drivers/gpu/drm/drm_panel.c
> +++ b/drivers/gpu/drm/drm_panel.c
> @@ -223,6 +223,15 @@ int drm_panel_get_modes(struct drm_panel *panel,
>  }
>  EXPORT_SYMBOL(drm_panel_get_modes);
>  
> +enum drm_panel_orientation drm_panel_get_orientation(struct drm_panel *panel)
const as mentioned by Stephen.

> +{
> +	if (panel && panel->funcs && panel->funcs->get_orientation)
> +		return panel->funcs->get_orientation(panel);
> +
> +	return DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
> +}
> +EXPORT_SYMBOL(drm_panel_get_orientation);
> +
>  #ifdef CONFIG_OF
>  /**
>   * of_drm_find_panel - look up a panel using a device tree node
> diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
> index d279ee455f01..5dadbf3b0370 100644
> --- a/include/drm/drm_panel.h
> +++ b/include/drm/drm_panel.h
> @@ -133,6 +133,15 @@ struct drm_panel_funcs {
>  	 * Allows panels to create panels-specific debugfs files.
>  	 */
>  	void (*debugfs_init)(struct drm_panel *panel, struct dentry *root);
> +
> +	/**
> +	 * @get_orientation:
> +	 *
> +	 * Return the panel orientation set by device tree or EDID.
> +	 *
> +	 * This function is optional.
> +	 */
> +	enum drm_panel_orientation (*get_orientation)(struct drm_panel *panel);

Please move this up so it is together with the other get_* methods, in
alphabetic order. That is, right after get_modes(), and then this also
matches the order in the .c file with is extra bonus.

With the two fixes:
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>

>  };
>  
>  /**
> @@ -202,6 +211,7 @@ int drm_panel_enable(struct drm_panel *panel);
>  int drm_panel_disable(struct drm_panel *panel);
>  
>  int drm_panel_get_modes(struct drm_panel *panel, struct drm_connector *connector);
> +enum drm_panel_orientation drm_panel_get_orientation(struct drm_panel *panel);
>  
>  #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
>  struct drm_panel *of_drm_find_panel(const struct device_node *np);
> -- 
> 2.36.1.255.ge46751e96f-goog

Re: [PATCH v4 1/8] drm/panel: Add an API drm_panel_get_orientation() to return panel orientation

Posted by Hans de Goede 3 years, 8 months ago

Hi,

On 6/6/22 21:20, Sam Ravnborg wrote:
> Hi Hsin-Yi,
> On Mon, Jun 06, 2022 at 11:24:24PM +0800, Hsin-Yi Wang wrote:
>> Panels usually call drm_connector_set_panel_orientation(), which is
>> later than drm/kms driver calling drm_dev_register(). This leads to a
>> WARN().
>>
>> The orientation property is known earlier. For example, some panels
>> parse the property through device tree during probe.
>>
>> Add an API to return the property from panel to drm/kms driver, so the
>> drivers are able to call drm_connector_set_panel_orientation() before
>> drm_dev_register().
>>
>> Suggested-by: Hans de Goede <hdegoede@redhat.com>
>> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
>> Reviewed-by: Hans de Goede <hdegoede@redhat.com>
>> Reviewed-by: Douglas Anderson <dianders@chromium.org>
>> ---
>> v3->v4: Add a blank line.
>> ---
>>  drivers/gpu/drm/drm_panel.c |  9 +++++++++
>>  include/drm/drm_panel.h     | 10 ++++++++++
>>  2 files changed, 19 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
>> index f634371c717a..e12056cfeca8 100644
>> --- a/drivers/gpu/drm/drm_panel.c
>> +++ b/drivers/gpu/drm/drm_panel.c
>> @@ -223,6 +223,15 @@ int drm_panel_get_modes(struct drm_panel *panel,
>>  }
>>  EXPORT_SYMBOL(drm_panel_get_modes);
>>  
>> +enum drm_panel_orientation drm_panel_get_orientation(struct drm_panel *panel)
> const as mentioned by Stephen.
> 
>> +{
>> +	if (panel && panel->funcs && panel->funcs->get_orientation)
>> +		return panel->funcs->get_orientation(panel);
>> +
>> +	return DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
>> +}
>> +EXPORT_SYMBOL(drm_panel_get_orientation);
>> +
>>  #ifdef CONFIG_OF
>>  /**
>>   * of_drm_find_panel - look up a panel using a device tree node
>> diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
>> index d279ee455f01..5dadbf3b0370 100644
>> --- a/include/drm/drm_panel.h
>> +++ b/include/drm/drm_panel.h
>> @@ -133,6 +133,15 @@ struct drm_panel_funcs {
>>  	 * Allows panels to create panels-specific debugfs files.
>>  	 */
>>  	void (*debugfs_init)(struct drm_panel *panel, struct dentry *root);
>> +
>> +	/**
>> +	 * @get_orientation:
>> +	 *
>> +	 * Return the panel orientation set by device tree or EDID.
>> +	 *
>> +	 * This function is optional.
>> +	 */
>> +	enum drm_panel_orientation (*get_orientation)(struct drm_panel *panel);
> 
> Please move this up so it is together with the other get_* methods, in
> alphabetic order. That is, right after get_modes(), and then this also
> matches the order in the .c file with is extra bonus.

The downside of moving this up is that it will break drivers which don't
use c99 style named-struct-field initializers for there drm_panel_funcs.

I admit that no drivers should be using the old style struct init, but
are we sure that that is the case?

Regards,

Hans



> 
> With the two fixes:
> Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
> 
>>  };
>>  
>>  /**
>> @@ -202,6 +211,7 @@ int drm_panel_enable(struct drm_panel *panel);
>>  int drm_panel_disable(struct drm_panel *panel);
>>  
>>  int drm_panel_get_modes(struct drm_panel *panel, struct drm_connector *connector);
>> +enum drm_panel_orientation drm_panel_get_orientation(struct drm_panel *panel);
>>  
>>  #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
>>  struct drm_panel *of_drm_find_panel(const struct device_node *np);
>> -- 
>> 2.36.1.255.ge46751e96f-goog
>

Re: [PATCH v4 1/8] drm/panel: Add an API drm_panel_get_orientation() to return panel orientation

Posted by Sam Ravnborg 3 years, 8 months ago

Hi Hans,

> > Please move this up so it is together with the other get_* methods, in
> > alphabetic order. That is, right after get_modes(), and then this also
> > matches the order in the .c file with is extra bonus.
> 
> The downside of moving this up is that it will break drivers which don't
> use c99 style named-struct-field initializers for there drm_panel_funcs.
> 
> I admit that no drivers should be using the old style struct init, but
> are we sure that that is the case?

There is no in-tree driver that uses old style struct init for
drm_panel_funcs - so we are safe here.

I just did a quick git grep -A 4 drm_panel_funcs to verify it,
browsing through the output did not reveal any old style users.

	Sam

Re: [PATCH v4 1/8] drm/panel: Add an API drm_panel_get_orientation() to return panel orientation

Posted by Stephen Boyd 3 years, 8 months ago

Quoting Hsin-Yi Wang (2022-06-06 08:24:24)
> diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
> index f634371c717a..e12056cfeca8 100644
> --- a/drivers/gpu/drm/drm_panel.c
> +++ b/drivers/gpu/drm/drm_panel.c
> @@ -223,6 +223,15 @@ int drm_panel_get_modes(struct drm_panel *panel,
>  }
>  EXPORT_SYMBOL(drm_panel_get_modes);
>
> +enum drm_panel_orientation drm_panel_get_orientation(struct drm_panel *panel)

Should 'panel' be marked const to indicate that it can't be modified?

> +{
> +       if (panel && panel->funcs && panel->funcs->get_orientation)
> +               return panel->funcs->get_orientation(panel);

Re: [PATCH v4 1/8] drm/panel: Add an API drm_panel_get_orientation() to return panel orientation

Posted by Hsin-Yi Wang 3 years, 8 months ago

On Tue, Jun 7, 2022 at 3:06 AM Stephen Boyd <swboyd@chromium.org> wrote:
>
> Quoting Hsin-Yi Wang (2022-06-06 08:24:24)
> > diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
> > index f634371c717a..e12056cfeca8 100644
> > --- a/drivers/gpu/drm/drm_panel.c
> > +++ b/drivers/gpu/drm/drm_panel.c
> > @@ -223,6 +223,15 @@ int drm_panel_get_modes(struct drm_panel *panel,
> >  }
> >  EXPORT_SYMBOL(drm_panel_get_modes);
> >
> > +enum drm_panel_orientation drm_panel_get_orientation(struct drm_panel *panel)
>
> Should 'panel' be marked const to indicate that it can't be modified?
>

But .get_orientation() will need to call to_XXX_panel, eg.
static inline struct boe_panel *to_boe_panel(struct drm_panel *panel)

==> .get_modes(panel) <-- can't be const.
==> drm_panel_get_orientation(panel) <-- can't be const.

We can definitely cast it in the functions, or make to_XXX_panel()
accept const, but I think this will lose the meaning of using const
anyway.

> > +{
> > +       if (panel && panel->funcs && panel->funcs->get_orientation)
> > +               return panel->funcs->get_orientation(panel);