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video: add display_timing and videomode

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Add display_timing structure and the according helper functions. This allows
the description of a display via its supported timing parameters.

Also, add helper functions to convert from display timings to a generic videomode
structure.

The struct display_timing specifies all needed parameters to describe the signal
properties of a display in one mode. This includes
    - ranges for signals that may have min-, max- and typical values
    - single integers for signals that can be on, off or are ignored
    - booleans for signals that are either on or off

As a display may support multiple modes like this, a struct display_timings is
added, that holds all given struct display_timing pointers and declares the
native mode of the display.

Although a display may state that a signal can be in a range, it is driven with
fixed values that indicate a videomode. Therefore graphic drivers don't need all
the information of struct display_timing, but would generate a videomode from
the given set of supported signal timings and work with that.

The video subsystems all define their own structs that describe a mode and work
with that (e.g. fb_videomode or drm_display_mode). To slowly replace all those
various structures and allow code reuse across those subsystems, add struct
videomode as a generic description.

This patch only includes the most basic fields in struct videomode. All missing
fields that are needed to have a really generic video mode description can be
added at a later stage.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de>
Acked-by: Thierry Reding <thierry.reding@avionic-design.de>
Tested-by: Thierry Reding <thierry.reding@avionic-design.de>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Afzal Mohammed <Afzal@ti.com>
Tested-by: Rob Clark <robclark@gmail.com>
Tested-by: Leela Krishna Amudala <leelakrishna.a@gmail.com>
This commit is contained in:
Steffen Trumtrar
2012-12-17 14:20:17 +01:00
parent ea4f3111ef
commit 8714c0cecf
6 changed files with 243 additions and 0 deletions
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include/video/videomode.h
+48
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/*
* Copyright 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>
*
* generic videomode description
*
* This file is released under the GPLv2
*/
#ifndef __LINUX_VIDEOMODE_H
#define __LINUX_VIDEOMODE_H
#include <linux/types.h>
#include <video/display_timing.h>
/*
* Subsystem independent description of a videomode.
* Can be generated from struct display_timing.
*/
struct videomode {
unsigned long pixelclock; /* pixelclock in Hz */
u32 hactive;
u32 hfront_porch;
u32 hback_porch;
u32 hsync_len;
u32 vactive;
u32 vfront_porch;
u32 vback_porch;
u32 vsync_len;
unsigned int dmt_flags; /* VESA DMT flags */
unsigned int data_flags; /* video data flags */
};
/**
* videomode_from_timing - convert display timing to videomode
* @disp: structure with all possible timing entries
* @vm: return value
* @index: index into the list of display timings in devicetree
*
* DESCRIPTION:
* This function converts a struct display_timing to a struct videomode.
*/
int videomode_from_timing(const struct display_timings *disp,
struct videomode *vm, unsigned int index);
#endif