From 38e42f121601fc0640c032871a38efa5a59cff68 Mon Sep 17 00:00:00 2001 From: Paul Walmsley Date: Thu, 26 Mar 2015 08:58:31 +0100 Subject: [PATCH] ARM: 8335/1: Documentation: DT bindings: Tegra AHB: document the legacy base address Documentation: DT bindings: Tegra AHB: require the legacy base address for existing chips Per Stephen Warren, note in the Tegra AHB DT binding documentation that we specifically deprecate any attempt to use the IP block's actual hardware base address, and advocate the use of the legacy "off-by-four" address in the 'regs' property, for Tegra chips with existing upstream Linux DT files that include a Tegra AHB node. This patch updates the documentation accordingly. Changing the existing kernel DT data isn't under consideration because Linux kernel DT data policy is to preserve compatibility between newer DT data files and older kernels. However, this additional step of changing the documentation should discourage others from sending kernel patches to try to change the legacy kernel DT data. Furthermore, for out-of-tree software (such as bootloaders or other operating systems) that may rely on Linux kernel DT binding documentation as an ABI (but not the Linux kernel DT data itself), such a change may allow future convergence with the Linux kernel DT data without additional code changes. Signed-off-by: Paul Walmsley Cc: Paul Walmsley Cc: Stephen Warren Cc: Alexandre Courbot Cc: Eduardo Valentin Cc: Ian Campbell Cc: Kumar Gala Cc: Mark Rutland Cc: Pawel Moll Cc: Rob Herring Cc: Thierry Reding Cc: devicetree@vger.kernel.org Cc: linux-kernel@vger.kernel.org Acked-by: Stephen Warren Signed-off-by: Russell King --- .../devicetree/bindings/arm/tegra/nvidia,tegra20-ahb.txt | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-ahb.txt b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-ahb.txt index 067c9790062f..9a4295b54539 100644 --- a/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-ahb.txt +++ b/Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-ahb.txt @@ -5,9 +5,12 @@ Required properties: Tegra30, must contain "nvidia,tegra30-ahb". Otherwise, must contain '"nvidia,-ahb", "nvidia,tegra30-ahb"' where is tegra124, tegra132, or tegra210. -- reg : Should contain 1 register ranges(address and length) +- reg : Should contain 1 register ranges(address and length). For + Tegra20, Tegra30, and Tegra114 chips, the value must be <0x6000c004 + 0x10c>. For Tegra124, Tegra132 and Tegra210 chips, the value should + be be <0x6000c000 0x150>. -Example: +Example (for a Tegra20 chip): ahb: ahb@6000c004 { compatible = "nvidia,tegra20-ahb"; reg = <0x6000c004 0x10c>; /* AHB Arbitration + Gizmo Controller */ -- 2.39.2