[PATCH] drm/sun4i: rgb: add missing calls to drm_panel_{prepare,unprepare}

[PATCH] drm/sun4i: rgb: add missing calls to drm_panel_{prepare,unprepare}

[Jonathan Liu]

If the enable-gpios property of a simple panel in device tree is set,
the GPIO is not toggled on/off because of missing calls to
drm_panel_prepare and drm_panel_unprepare.

Signed-off-by: Jonathan Liu <net147@gmail.com>
---
 drivers/gpu/drm/sun4i/sun4i_rgb.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/sun4i/sun4i_rgb.c b/drivers/gpu/drm/sun4i/sun4i_rgb.c
index f5bbac6..d6943e9 100644
--- a/drivers/gpu/drm/sun4i/sun4i_rgb.c
+++ b/drivers/gpu/drm/sun4i/sun4i_rgb.c
@@ -151,6 +151,7 @@ static void sun4i_rgb_encoder_enable(struct drm_encoder *encoder)
 
 	DRM_DEBUG_DRIVER("Enabling RGB output\n");
 
+	drm_panel_prepare(tcon->panel);
 	drm_panel_enable(tcon->panel);
 	sun4i_tcon_channel_enable(tcon, 0);
 }
@@ -165,6 +166,7 @@ static void sun4i_rgb_encoder_disable(struct drm_encoder *encoder)
 
 	sun4i_tcon_channel_disable(tcon, 0);
 	drm_panel_disable(tcon->panel);
+	drm_panel_unprepare(tcon->panel);
 }
 
 static void sun4i_rgb_encoder_mode_set(struct drm_encoder *encoder,
-- 
2.9.3

Re: [PATCH] drm/sun4i: rgb: add missing calls to drm_panel_{prepare,unprepare}

[Maxime Ripard]

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Hi,

On Tue, Aug 30, 2016 at 04:55:00PM +1000, Jonathan Liu wrote:
> If the enable-gpios property of a simple panel in device tree is set,
> the GPIO is not toggled on/off because of missing calls to
> drm_panel_prepare and drm_panel_unprepare.
> 
> Signed-off-by: Jonathan Liu <net147@gmail.com>

This was not applying properly, but I merged it.

Please make sure that it applies on top of the current next branch.

Good catch, thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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Re: [PATCH] drm/sun4i: rgb: add missing calls to drm_panel_{prepare, unprepare}

[Emil Velikov]

On 30 August 2016 at 07:55, Jonathan Liu <net147@gmail.com> wrote:
> If the enable-gpios property of a simple panel in device tree is set,
> the GPIO is not toggled on/off because of missing calls to
> drm_panel_prepare and drm_panel_unprepare.
>
> Signed-off-by: Jonathan Liu <net147@gmail.com>
> ---
>  drivers/gpu/drm/sun4i/sun4i_rgb.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/sun4i/sun4i_rgb.c b/drivers/gpu/drm/sun4i/sun4i_rgb.c
> index f5bbac6..d6943e9 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_rgb.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_rgb.c
> @@ -151,6 +151,7 @@ static void sun4i_rgb_encoder_enable(struct drm_encoder *encoder)
>
>         DRM_DEBUG_DRIVER("Enabling RGB output\n");
>
> +       drm_panel_prepare(tcon->panel);
>         drm_panel_enable(tcon->panel);
IMHO it's worth having a _prepare_enable, and alike on the dtor side,
similar to clk. The clk helper attributes when .enable() fails, which
is a good idea. Looking on the drm side - all the users of such
helper(s) don't bother checking neither .prepare or .enable. So
updating that alongside the introduction would be a great move ;-)

Just an idea about another small task.
Emil

P.S. Skimming through v4.7 mediatek (mtk) driver looks a bit
assymetrical wrt using the drm_panel API. Worth checking if things
have improved with later versions ?