[U-Boot] [PATCH 2/2] video: tegra: refuse to bind to disabled dcs

[Simon Glass]

On 19 April 2016 at 16:19, Stephen Warren <swarren at wwwdotorg.org> wrote:
> From: Stephen Warren <swarren at nvidia.com>
>
> This prevents the following boot-time message on any board where only the
> first DC is in use, yet the DC's DT node is enabled:
>
> stdio_add_devices: Video device failed (ret=-22)
>
> (This happens on at least Harmony, Ventana, and likely any other Tegra20
> board with display enabled other than Seaboard).
>
> The Tegra DC's DT node represents a display controller. It may itself
> drive an integrated RGB display output, or be used by some other display
> controller such as HDMI. For this reason the DC node itself is not
> enabled/disabled in DT; the DC itself is considered a shared resource, not
> the final (board-specific) display output. The node should instantiate a
> display output driver only if the rgb subnode is enabled. Other output
> drivers are free to use the DC if they are enabled and their DT node
> references the DC's DT node. Adapt the Tegra display drivers' bind()
> routine to only bind to the DC's DT node if the RGB subnode is enabled.
>
> Now that the display driver does the right thing, remove the workaround
> for this issue from Seaboard's DT file.
>
> Cc: Thierry Reding <treding at nvidia.com>
> Signed-off-by: Stephen Warren <swarren at nvidia.com>
> ---
> Thierry, I assume this is how the DC nodes are intended to be interpreted?
> It's certainly how the kernel's DT files and driver work, even if by
> accident.
> ---
> arch/arm/dts/tegra20-seaboard.dts | 4 ----
> drivers/video/tegra.c | 7 +++++++
> 2 files changed, 7 insertions(+), 4 deletions(-)

Well it seems reasonable to me.

Reviewed-by: Simon Glass <sjg at chromium.org>