• Paul Walmsley's avatar
    ARM: 8335/1: Documentation: DT bindings: Tegra AHB: document the legacy base address · 38e42f12
    Paul Walmsley authored
    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: default avatarPaul Walmsley <paul@pwsan.com>
    Cc: Paul Walmsley <pwalmsley@nvidia.com>
    Cc: Stephen Warren <swarren@wwwdotorg.org>
    Cc: Alexandre Courbot <gnurou@gmail.com>
    Cc: Eduardo Valentin <edubezval@gmail.com>
    Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
    Cc: Kumar Gala <galak@codeaurora.org>
    Cc: Mark Rutland <mark.rutland@arm.com>
    Cc: Pawel Moll <pawel.moll@arm.com>
    Cc: Rob Herring <robh+dt@kernel.org>
    Cc: Thierry Reding <thierry.reding@gmail.com>
    Cc: devicetree@vger.kernel.org
    Cc: linux-kernel@vger.kernel.org
    Acked-by: default avatarStephen Warren <swarren@nvidia.com>
    Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
    38e42f12
nvidia,tegra20-ahb.txt 673 Bytes