path: root/Documentation/devicetree
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authorThierry Reding <treding@nvidia.com>2014-01-09 17:08:36 +0100
committerThierry Reding <treding@nvidia.com>2014-01-23 15:51:32 +0100
commit13411ddd319057ae334a4084ebcf2c741b317f34 (patch)
tree9915698fb7fe169acd53b9b7f75347524ed04a98 /Documentation/devicetree
parent70bf6878a874523e4b62992d07b5739298f8c1eb (diff)
drm/tegra: Obtain head number from DT
The head number of a given display controller is fixed in hardware and required to program outputs appropriately. Relying on the driver probe order to determine this number will not work, since that could yield a situation where the second head was probed first and would be assigned head number 0 instead of 1. By explicitly specifying the head number in the device tree, it is no longer necessary to rely on these assumptions. As a fallback, if the property isn't available, derive the head number from the display controller node's position in the device tree. That's somewhat more reliable than the previous default but not a proper solution. Tested-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
Diffstat (limited to 'Documentation/devicetree')
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/gpu/nvidia,tegra20-host1x.txt b/Documentation/devicetree/bindings/gpu/nvidia,tegra20-host1x.txt
index 9e9008f8fa32..efaeec8961b6 100644
--- a/Documentation/devicetree/bindings/gpu/nvidia,tegra20-host1x.txt
+++ b/Documentation/devicetree/bindings/gpu/nvidia,tegra20-host1x.txt
@@ -118,6 +118,9 @@ of the following host1x client modules:
See ../reset/reset.txt for details.
- reset-names: Must include the following entries:
- dc
+ - nvidia,head: The number of the display controller head. This is used to
+ setup the various types of output to receive video data from the given
+ head.
Each display controller node has a child node, named "rgb", that represents
the RGB output associated with the controller. It can take the following

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