From 9ee4cd1aa3eec2f405652dc51779612104feebef Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Fri, 14 Nov 2014 13:26:47 +0100 Subject: dt-bindings: Add a clocks property to the simple-framebuffer binding A simple-framebuffer node represents a framebuffer setup by the firmware / bootloader. Such a framebuffer may have a number of clocks in use, add a property to communicate this to the OS. Signed-off-by: Hans de Goede Reviewed-by: Mike Turquette Acked-by: Geert Uytterhoeven Reviewed-by: Maxime Ripard Acked-by: Grant Likely Signed-off-by: Tomi Valkeinen --- .../devicetree/bindings/video/simple-framebuffer.txt | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/video/simple-framebuffer.txt b/Documentation/devicetree/bindings/video/simple-framebuffer.txt index 70c26f3a5b9a..8f35718f4f5b 100644 --- a/Documentation/devicetree/bindings/video/simple-framebuffer.txt +++ b/Documentation/devicetree/bindings/video/simple-framebuffer.txt @@ -1,8 +1,8 @@ Simple Framebuffer -A simple frame-buffer describes a raw memory region that may be rendered to, -with the assumption that the display hardware has already been set up to scan -out from that buffer. +A simple frame-buffer describes a frame-buffer setup by firmware or +the bootloader, with the assumption that the display hardware has already +been set up to scan out from the memory pointed to by the reg property. Required properties: - compatible: "simple-framebuffer" @@ -14,6 +14,12 @@ Required properties: - r5g6b5 (16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b). - a8b8g8r8 (32-bit pixels, d[31:24]=a, d[23:16]=b, d[15:8]=g, d[7:0]=r). +Optional properties: +- clocks : List of clocks used by the framebuffer. Clocks listed here + are expected to already be configured correctly. The OS must + ensure these clocks are not modified or disabled while the + simple framebuffer remains active. + Example: framebuffer { -- cgit v1.2.3 From 9bb5b20f5d983e98d9a1cc7b7af5877b0f1c791b Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Fri, 14 Nov 2014 13:26:51 +0100 Subject: dt-bindings: simplefb: Specify node location and handoff related properties Since simplefb nodes do not relate directly to hw typically they have been placed in the root of the devicetree. As the represent runtime information having them as sub-nodes of /chosen is more logical, specify this. Also specify when to set the chosen stdout-path property to a simplefb node. For reliable handover to a hardware specific driver, that driver needs to know which simplefb to unregister when taking over, specify how the hw driver can find the matching simplefb node. Last add some advice on how to fill and use simplefb nodes from a firmware pov. Signed-off-by: Hans de Goede Acked-by: Geert Uytterhoeven Acked-by: Maxime Ripard Signed-off-by: Tomi Valkeinen --- .../bindings/video/simple-framebuffer.txt | 58 +++++++++++++++++++++- 1 file changed, 57 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/video/simple-framebuffer.txt b/Documentation/devicetree/bindings/video/simple-framebuffer.txt index 8f35718f4f5b..f8fb7e6e5609 100644 --- a/Documentation/devicetree/bindings/video/simple-framebuffer.txt +++ b/Documentation/devicetree/bindings/video/simple-framebuffer.txt @@ -4,6 +4,40 @@ A simple frame-buffer describes a frame-buffer setup by firmware or the bootloader, with the assumption that the display hardware has already been set up to scan out from the memory pointed to by the reg property. +Since simplefb nodes represent runtime information they must be sub-nodes of +the chosen node (*). Simplefb nodes must be named "framebuffer@
". + +If the devicetree contains nodes for the display hardware used by a simplefb, +then the simplefb node must contain a property called "display", which +contains a phandle pointing to the primary display hw node, so that the OS +knows which simplefb to disable when handing over control to a driver for the +real hardware. The bindings for the hw nodes must specify which node is +considered the primary node. + +It is advised to add display# aliases to help the OS determine how to number +things. If display# aliases are used, then if the simplefb node contains a +"display" property then the /aliases/display# path must point to the display +hw node the "display" property points to, otherwise it must point directly +to the simplefb node. + +If a simplefb node represents the preferred console for user interaction, +then the chosen node's stdout-path property should point to it, or to the +primary display hw node, as with display# aliases. If display aliases are +used then it should be set to the alias instead. + +It is advised that devicetree files contain pre-filled, disabled framebuffer +nodes, so that the firmware only needs to update the mode information and +enable them. This way if e.g. later on support for more display clocks get +added, the simplefb nodes will already contain this info and the firmware +does not need to be updated. + +If pre-filled framebuffer nodes are used, they should be named +"framebuffer#-", e.g. "framebuffer0-hdmi". The output should be +included in the name since different outputs typically require different +clocks and the clocks are part of the pre-populated nodes. The firmware must +rename the nodes to the standard "framebuffer@
" name using the +runtime chosen address when enabling the nodes. + Required properties: - compatible: "simple-framebuffer" - reg: Should contain the location and size of the framebuffer memory. @@ -19,14 +53,36 @@ Optional properties: are expected to already be configured correctly. The OS must ensure these clocks are not modified or disabled while the simple framebuffer remains active. +- display : phandle pointing to the primary display hardware node Example: - framebuffer { +aliases { + display0 = &lcdc0; +} + +chosen { + framebuffer0: framebuffer@1d385000 { compatible = "simple-framebuffer"; reg = <0x1d385000 (1600 * 1200 * 2)>; width = <1600>; height = <1200>; stride = <(1600 * 2)>; format = "r5g6b5"; + clocks = <&ahb_gates 36>, <&ahb_gates 43>, <&ahb_gates 44>; + display = <&lcdc0>; + }; + stdout-path = "display0"; +}; + +soc@01c00000 { + lcdc0: lcdc@1c0c000 { + compatible = "allwinner,sun4i-a10-lcdc"; + ... }; +}; + + +*) Older devicetree files may have a compatible = "simple-framebuffer" node +in a different place, operating systems must first enumerate any compatible +nodes found under chosen and then check for other compatible nodes. -- cgit v1.2.3 From 5d85a8478ec8a1956f08ad72d1601a3c5cb60b1e Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Tue, 18 Nov 2014 12:10:50 +0100 Subject: dt-bindings: simplefb: Drop the advice about using a specific path for nodes This goes contrary to how devicetree usually works, so drop it. Instead if the firmware needs to be able to find a specific node it should use a platform specific compatible + properties for this. Signed-off-by: Hans de Goede Acked-by: Grant Likely Signed-off-by: Tomi Valkeinen --- Documentation/devicetree/bindings/video/simple-framebuffer.txt | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/video/simple-framebuffer.txt b/Documentation/devicetree/bindings/video/simple-framebuffer.txt index f8fb7e6e5609..4474ef6e0b95 100644 --- a/Documentation/devicetree/bindings/video/simple-framebuffer.txt +++ b/Documentation/devicetree/bindings/video/simple-framebuffer.txt @@ -31,12 +31,10 @@ enable them. This way if e.g. later on support for more display clocks get added, the simplefb nodes will already contain this info and the firmware does not need to be updated. -If pre-filled framebuffer nodes are used, they should be named -"framebuffer#-", e.g. "framebuffer0-hdmi". The output should be -included in the name since different outputs typically require different -clocks and the clocks are part of the pre-populated nodes. The firmware must -rename the nodes to the standard "framebuffer@
" name using the -runtime chosen address when enabling the nodes. +If pre-filled framebuffer nodes are used, the firmware may need extra +information to find the right node. In that case an extra platform specific +compatible and platform specific properties should be used and documented, +see e.g. simple-framebuffer-sunxi.txt . Required properties: - compatible: "simple-framebuffer" -- cgit v1.2.3 From b14c99299b9e11615f512ddadd6ca98dc41f2cb8 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Tue, 18 Nov 2014 12:10:51 +0100 Subject: dt-bindings: simplefb-sunxi: Add sunxi simplefb extensions If pre-filled framebuffer nodes are used, the firmware may need extra properties to find the right node. This documents the properties to use for this on sunxi platforms. Signed-off-by: Hans de Goede Acked-by: Grant Likely Signed-off-by: Tomi Valkeinen --- .../bindings/video/simple-framebuffer-sunxi.txt | 33 ++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 Documentation/devicetree/bindings/video/simple-framebuffer-sunxi.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/video/simple-framebuffer-sunxi.txt b/Documentation/devicetree/bindings/video/simple-framebuffer-sunxi.txt new file mode 100644 index 000000000000..c46ba641a1df --- /dev/null +++ b/Documentation/devicetree/bindings/video/simple-framebuffer-sunxi.txt @@ -0,0 +1,33 @@ +Sunxi specific Simple Framebuffer bindings + +This binding documents sunxi specific extensions to the simple-framebuffer +bindings. The sunxi simplefb u-boot code relies on the devicetree containing +pre-populated simplefb nodes. + +These extensions are intended so that u-boot can select the right node based +on which pipeline is being used. As such they are solely intended for +firmware / bootloader use, and the OS should ignore them. + +Required properties: +- compatible: "allwinner,simple-framebuffer" +- allwinner,pipeline, one of: + "de_be0-lcd0" + "de_be1-lcd1" + "de_be0-lcd0-hdmi" + "de_be1-lcd1-hdmi" + +Example: + +chosen { + #address-cells = <1>; + #size-cells = <1>; + ranges; + + framebuffer@0 { + compatible = "allwinner,simple-framebuffer", "simple-framebuffer"; + allwinner,pipeline = "de_be0-lcd0-hdmi"; + clocks = <&pll5 1>, <&ahb_gates 36>, <&ahb_gates 43>, + <&ahb_gates 44>; + status = "disabled"; + }; +}; -- cgit v1.2.3