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authorPaul Walmsley <[email protected]>2015-03-26 08:58:31 +0100
committerRussell King <[email protected]>2015-04-02 10:03:56 +0100
commit38e42f121601fc0640c032871a38efa5a59cff68 (patch)
tree3bd8c7a4f4d424edf82ce4f3081834efa2ca28bf
parentce7a10b0ff3db63a43d2d7885aa0f43dc8c96419 (diff)
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 <[email protected]> Cc: Paul Walmsley <[email protected]> Cc: Stephen Warren <[email protected]> Cc: Alexandre Courbot <[email protected]> Cc: Eduardo Valentin <[email protected]> Cc: Ian Campbell <[email protected]> Cc: Kumar Gala <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Pawel Moll <[email protected]> Cc: Rob Herring <[email protected]> Cc: Thierry Reding <[email protected]> Cc: [email protected] Cc: [email protected] Acked-by: Stephen Warren <[email protected]> Signed-off-by: Russell King <[email protected]>
-rw-r--r--Documentation/devicetree/bindings/arm/tegra/nvidia,tegra20-ahb.txt7
1 files 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,<chip>-ahb", "nvidia,tegra30-ahb"' where <chip> 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 */