dt-bindings: chosen: Add "power-state-change-reason" nvmem property #174
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A lot of systems (especially embedded) store the last shutdown/reboot
reason in NVMEM. This could be anything from "over temperature" or
"brown-out" to an "EC panic" or watchdog reset.
There's currently no standard way for firmware to tell the kernel where
to find this information.
The /chosen node is already used for passing global, firmware-provided
data like 'bootargs' and 'stdout-path'. Let's use it for this, too.
This patch adds a binding for a new generic NVMEM cell name in /chosen:
"power-state-change-reason".
Example from the binding:
chosen {
nvmem-cells = <&pscr_cell>;
nvmem-cell-names = "power-state-change-reason";
};
Signed-off-by: Oleksij Rempel <[email protected]>
olerem
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Hi all,
I'm proposing a new generic property for the /chosen node to identify
an NVMEM cell containing the last system shutdown/reboot reason. Many
embedded systems record this (e.g., "over-temperature", "brown-out"),
but there's no standard way to pass this location to the OS.
I'm sending this as an RFC patch because I'm uncertain about a few points:
Is the /chosen node the right conceptual place for
this? It feels correct for a global, firmware-provided property,
much like 'stdout-path', but I'd
like to be sure.
Is this the right file to patch (
chosen.yaml)? Or should thisbe defined in a more central NVMEM binding?
Are the '$ref's correct? I'm referencing the existing meta-schema
nvmem.yaml from schema (feels wrong). Is this the standard way to re-use
properties from another schema?
Any feedback on the approach or the implementation would be greatly appreciated.
Thanks,
Oleksij