Re: [PATCH 07/12] drm: drm_display_mode: add signal polarity flags

[Andrzej Hajda <a.hajda@samsung.com>]

Hi Denis,

Thanks for the patch.

On 03/13/2014 06:17 PM, Denis Carikli wrote:
> We need a way to pass signal polarity informations
>   between DRM panels, and the display drivers.
> 
> To do that, a pol_flags field was added to drm_display_mode.
> 
> Signed-off-by: Denis Carikli <denis@eukrea.com>
> ---
> ChangeLog v10->v11:
> - Since the imx-drm won't be able to retrive its regulators
>   from the device tree when using display-timings nodes,
>   and that I was told that the drm simple-panel driver 
>   already supported that, I then, instead, added what was
>   lacking to make the eukrea displays work with the
>   drm-simple-panel driver.
> 
>   That required a way to get back the display polarity
>   informations from the imx-drm driver without affecting
>   userspace.
> ---
>  include/drm/drm_crtc.h |    8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
> index f764654..61a4fe1 100644
> --- a/include/drm/drm_crtc.h
> +++ b/include/drm/drm_crtc.h
> @@ -131,6 +131,13 @@ enum drm_mode_status {
>  
>  #define DRM_MODE_FLAG_3D_MAX	DRM_MODE_FLAG_3D_SIDE_BY_SIDE_HALF
>  
> +#define DRM_MODE_FLAG_POL_PIXDATA_NEGEDGE	BIT(1)
> +#define DRM_MODE_FLAG_POL_PIXDATA_POSEDGE	BIT(2)
> +#define DRM_MODE_FLAG_POL_PIXDATA_PRESERVE	BIT(3)
> +#define DRM_MODE_FLAG_POL_DE_NEGEDGE		BIT(4)
> +#define DRM_MODE_FLAG_POL_DE_POSEDGE		BIT(5)
> +#define DRM_MODE_FLAG_POL_DE_PRESERVE		BIT(6)

Could you add some description to these flags.
What are *_PRESERVE flags for?
Are those flags 1:1 compatible with respective 'videomode:flags'?
I guess DE flags should be rather DRM_MODE_FLAG_POL_DE_(LOW|HIGH), am I
right?

Regards
Andrzej


> +
>  struct drm_display_mode {
>  	/* Header */
>  	struct list_head head;
> @@ -183,6 +190,7 @@ struct drm_display_mode {
>  	int vrefresh;		/* in Hz */
>  	int hsync;		/* in kHz */
>  	enum hdmi_picture_aspect picture_aspect_ratio;
> +	unsigned int pol_flags;
>  };
>  
>  static inline bool drm_mode_is_stereo(const struct drm_display_mode *mode)
>