summaryrefslogtreecommitdiff
path: root/Documentation/devicetree
diff options
context:
space:
mode:
authorDave Airlie <airlied@redhat.com>2013-02-08 06:34:44 +0400
committerDave Airlie <airlied@redhat.com>2013-02-08 06:34:44 +0400
commited914f69f8f979ea2b664abc4f1437235cf3db35 (patch)
tree43d839d79d02f4a9415199a2db7a4b6cfeb281eb /Documentation/devicetree
parentbb0f78dd7ded88082b2430c43c65bc821c4ea360 (diff)
parentedb37a95c58147f89713e6c5cd220fa8fdfb4833 (diff)
downloadlinux-ed914f69f8f979ea2b664abc4f1437235cf3db35.tar.xz
Merge tag 'of_videomode_helper' of git://git.pengutronix.de/git/str/linux into drm-next
videomode helpers for of + devicetree stuff, required for new kms drivers (not the fbdev maintainer). * tag 'of_videomode_helper' of git://git.pengutronix.de/git/str/linux: drm_modes: add of_videomode helpers drm_modes: add videomode helpers fbmon: add of_videomode helpers fbmon: add videomode helpers video: add of helper for display timings/videomode video: add display_timing and videomode viafb: rename display_timing to via_display_timing
Diffstat (limited to 'Documentation/devicetree')
-rw-r--r--Documentation/devicetree/bindings/video/display-timing.txt109
1 files changed, 109 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/video/display-timing.txt b/Documentation/devicetree/bindings/video/display-timing.txt
new file mode 100644
index 000000000000..150038552bc3
--- /dev/null
+++ b/Documentation/devicetree/bindings/video/display-timing.txt
@@ -0,0 +1,109 @@
+display-timing bindings
+=======================
+
+display-timings node
+--------------------
+
+required properties:
+ - none
+
+optional properties:
+ - native-mode: The native mode for the display, in case multiple modes are
+ provided. When omitted, assume the first node is the native.
+
+timing subnode
+--------------
+
+required properties:
+ - hactive, vactive: display resolution
+ - hfront-porch, hback-porch, hsync-len: horizontal display timing parameters
+ in pixels
+ vfront-porch, vback-porch, vsync-len: vertical display timing parameters in
+ lines
+ - clock-frequency: display clock in Hz
+
+optional properties:
+ - hsync-active: hsync pulse is active low/high/ignored
+ - vsync-active: vsync pulse is active low/high/ignored
+ - de-active: data-enable pulse is active low/high/ignored
+ - pixelclk-active: with
+ - active high = drive pixel data on rising edge/
+ sample data on falling edge
+ - active low = drive pixel data on falling edge/
+ sample data on rising edge
+ - ignored = ignored
+ - interlaced (bool): boolean to enable interlaced mode
+ - doublescan (bool): boolean to enable doublescan mode
+
+All the optional properties that are not bool follow the following logic:
+ <1>: high active
+ <0>: low active
+ omitted: not used on hardware
+
+There are different ways of describing the capabilities of a display. The
+devicetree representation corresponds to the one commonly found in datasheets
+for displays. If a display supports multiple signal timings, the native-mode
+can be specified.
+
+The parameters are defined as:
+
+ +----------+-------------------------------------+----------+-------+
+ | | ↑ | | |
+ | | |vback_porch | | |
+ | | ↓ | | |
+ +----------#######################################----------+-------+
+ | # ↑ # | |
+ | # | # | |
+ | hback # | # hfront | hsync |
+ | porch # | hactive # porch | len |
+ |<-------->#<-------+--------------------------->#<-------->|<----->|
+ | # | # | |
+ | # |vactive # | |
+ | # | # | |
+ | # ↓ # | |
+ +----------#######################################----------+-------+
+ | | ↑ | | |
+ | | |vfront_porch | | |
+ | | ↓ | | |
+ +----------+-------------------------------------+----------+-------+
+ | | ↑ | | |
+ | | |vsync_len | | |
+ | | ↓ | | |
+ +----------+-------------------------------------+----------+-------+
+
+Example:
+
+ display-timings {
+ native-mode = <&timing0>;
+ timing0: 1080p24 {
+ /* 1920x1080p24 */
+ clock-frequency = <52000000>;
+ hactive = <1920>;
+ vactive = <1080>;
+ hfront-porch = <25>;
+ hback-porch = <25>;
+ hsync-len = <25>;
+ vback-porch = <2>;
+ vfront-porch = <2>;
+ vsync-len = <2>;
+ hsync-active = <1>;
+ };
+ };
+
+Every required property also supports the use of ranges, so the commonly used
+datasheet description with minimum, typical and maximum values can be used.
+
+Example:
+
+ timing1: timing {
+ /* 1920x1080p24 */
+ clock-frequency = <148500000>;
+ hactive = <1920>;
+ vactive = <1080>;
+ hsync-len = <0 44 60>;
+ hfront-porch = <80 88 95>;
+ hback-porch = <100 148 160>;
+ vfront-porch = <0 4 6>;
+ vback-porch = <0 36 50>;
+ vsync-len = <0 5 6>;
+ };