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author | Steffen Trumtrar <s.trumtrar@pengutronix.de> | 2012-12-17 17:20:17 +0400 |
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committer | Steffen Trumtrar <s.trumtrar@pengutronix.de> | 2013-01-24 12:03:04 +0400 |
commit | 8714c0cecfc28f7ce73a520be4831f09743c4fd7 (patch) | |
tree | e0115b23586ce857c0a1257a7a26d638bf2aa3b3 /include/video | |
parent | ea4f3111ef0daffa1d11fded6f375227febca458 (diff) | |
download | linux-8714c0cecfc28f7ce73a520be4831f09743c4fd7.tar.xz |
video: add display_timing and videomode
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>
Diffstat (limited to 'include/video')
-rw-r--r-- | include/video/display_timing.h | 124 | ||||
-rw-r--r-- | include/video/videomode.h | 48 |
2 files changed, 172 insertions, 0 deletions
diff --git a/include/video/display_timing.h b/include/video/display_timing.h new file mode 100644 index 000000000000..71e9a383a981 --- /dev/null +++ b/include/video/display_timing.h @@ -0,0 +1,124 @@ +/* + * Copyright 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de> + * + * description of display timings + * + * This file is released under the GPLv2 + */ + +#ifndef __LINUX_DISPLAY_TIMING_H +#define __LINUX_DISPLAY_TIMING_H + +#include <linux/bitops.h> +#include <linux/types.h> + +/* VESA display monitor timing parameters */ +#define VESA_DMT_HSYNC_LOW BIT(0) +#define VESA_DMT_HSYNC_HIGH BIT(1) +#define VESA_DMT_VSYNC_LOW BIT(2) +#define VESA_DMT_VSYNC_HIGH BIT(3) + +/* display specific flags */ +#define DISPLAY_FLAGS_DE_LOW BIT(0) /* data enable flag */ +#define DISPLAY_FLAGS_DE_HIGH BIT(1) +#define DISPLAY_FLAGS_PIXDATA_POSEDGE BIT(2) /* drive data on pos. edge */ +#define DISPLAY_FLAGS_PIXDATA_NEGEDGE BIT(3) /* drive data on neg. edge */ +#define DISPLAY_FLAGS_INTERLACED BIT(4) +#define DISPLAY_FLAGS_DOUBLESCAN BIT(5) + +/* + * A single signal can be specified via a range of minimal and maximal values + * with a typical value, that lies somewhere inbetween. + */ +struct timing_entry { + u32 min; + u32 typ; + u32 max; +}; + +enum timing_entry_index { + TE_MIN = 0, + TE_TYP = 1, + TE_MAX = 2, +}; + +/* + * Single "mode" entry. This describes one set of signal timings a display can + * have in one setting. This struct can later be converted to struct videomode + * (see include/video/videomode.h). As each timing_entry can be defined as a + * range, one struct display_timing may become multiple struct videomodes. + * + * Example: hsync active high, vsync active low + * + * Active Video + * Video ______________________XXXXXXXXXXXXXXXXXXXXXX_____________________ + * |<- sync ->|<- back ->|<----- active ----->|<- front ->|<- sync.. + * | | porch | | porch | + * + * HSync _|¯¯¯¯¯¯¯¯¯¯|___________________________________________|¯¯¯¯¯¯¯¯¯ + * + * VSync ¯|__________|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|_________ + */ +struct display_timing { + struct timing_entry pixelclock; + + struct timing_entry hactive; /* hor. active video */ + struct timing_entry hfront_porch; /* hor. front porch */ + struct timing_entry hback_porch; /* hor. back porch */ + struct timing_entry hsync_len; /* hor. sync len */ + + struct timing_entry vactive; /* ver. active video */ + struct timing_entry vfront_porch; /* ver. front porch */ + struct timing_entry vback_porch; /* ver. back porch */ + struct timing_entry vsync_len; /* ver. sync len */ + + unsigned int dmt_flags; /* VESA DMT flags */ + unsigned int data_flags; /* video data flags */ +}; + +/* + * This describes all timing settings a display provides. + * The native_mode is the default setting for this display. + * Drivers that can handle multiple videomodes should work with this struct and + * convert each entry to the desired end result. + */ +struct display_timings { + unsigned int num_timings; + unsigned int native_mode; + + struct display_timing **timings; +}; + +/* get value specified by index from struct timing_entry */ +static inline u32 display_timing_get_value(const struct timing_entry *te, + enum timing_entry_index index) +{ + switch (index) { + case TE_MIN: + return te->min; + break; + case TE_TYP: + return te->typ; + break; + case TE_MAX: + return te->max; + break; + default: + return te->typ; + } +} + +/* get one entry from struct display_timings */ +static inline struct display_timing *display_timings_get(const struct + display_timings *disp, + unsigned int index) +{ + if (disp->num_timings > index) + return disp->timings[index]; + else + return NULL; +} + +void display_timings_release(struct display_timings *disp); + +#endif diff --git a/include/video/videomode.h b/include/video/videomode.h new file mode 100644 index 000000000000..a42156234dd4 --- /dev/null +++ b/include/video/videomode.h @@ -0,0 +1,48 @@ +/* + * 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 |