diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/device-tree-bindings/firmware/nvidia,tegra186-bpmp.txt | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/doc/device-tree-bindings/firmware/nvidia,tegra186-bpmp.txt b/doc/device-tree-bindings/firmware/nvidia,tegra186-bpmp.txt index 9a3864f569..447252e882 100644 --- a/doc/device-tree-bindings/firmware/nvidia,tegra186-bpmp.txt +++ b/doc/device-tree-bindings/firmware/nvidia,tegra186-bpmp.txt @@ -38,6 +38,24 @@ implemented by this node: - .../reset/reset.txt - <dt-bindings/reset/tegra186-reset.h> +The BPMP implements some services which must be represented by separate nodes. +For example, it can provide access to certain I2C controllers, and the I2C +bindings represent each I2C controller as a device tree node. Such nodes should +be nested directly inside the main BPMP node. + +Software can determine whether a child node of the BPMP node represents a device +by checking for a compatible property. Any node with a compatible property +represents a device that can be instantiated. Nodes without a compatible +property may be used to provide configuration information regarding the BPMP +itself, although no such configuration nodes are currently defined by this +binding. + +The BPMP firmware defines no single global name-/numbering-space for such +services. Put another way, the numbering scheme for I2C buses is distinct from +the numbering scheme for any other service the BPMP may provide (e.g. a future +hypothetical SPI bus service). As such, child device nodes will have no reg +property, and the BPMP node will have no #address-cells or #size-cells property. + The shared memory bindings for BPMP ----------------------------------- @@ -78,4 +96,9 @@ bpmp { #clock-cells = <1>; #power-domain-cells = <1>; #reset-cells = <1>; + + i2c { + compatible = "..."; + ... + }; }; |