On 07/06/16 14:22, Mark Rutland wrote:
On Mon, Jun 06, 2016 at 04:53:58PM +0100, Sudeep Holla wrote:
The System Control Processor (SCP) provides peripheral devices with
power domains that can be enabled and disabled viathe System Control
and Power Interface (SCPI) Message Protocol. Add bindings to allow
probing of these device power domians.
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: devicetree@xxxxxxxxxxxxxxx
Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
---
Documentation/devicetree/bindings/arm/arm,scpi.txt | 34 ++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/Documentation/devicetree/bindings/arm/arm,scpi.txt b/Documentation/devicetree/bindings/arm/arm,scpi.txt
index 313dabdc14f9..7141670d649b 100644
--- a/Documentation/devicetree/bindings/arm/arm,scpi.txt
+++ b/Documentation/devicetree/bindings/arm/arm,scpi.txt
@@ -87,10 +87,33 @@ SCPI provides an API to access the various sensors on the SoC.
implementation for the IDs to use. For Juno
R0 and Juno R1 refer to [3].
+Power domain bindings for the power domains based on SCPI Message Protocol
+------------------------------------------------------------
+
+This binding uses the generic power domain binding[4].
+
+PM domain providers
+===================
+
+Required properties:
+ - #power-domain-cells : Should be 1. Contains the device or the power
+ domain ID value used by SCPI commands.
+ - num-domains: Total number of power domains provided by SCPI. This is
+ needed as the SCPI message protocol lacks a mechanism to
+ query this information runtime.
^
I guess there should be an 'at' here.
Will fix.
Are domain IDs zero-based and definitely non-sparse?
Yes
What exactly does this matter for? Just for validation at parsing time,
or is this strictly required for correctness?
This is mainly to know the maximum number of power domains that firmware
supports. This will help the software handling the provider part to
setup the information in advance before any consumer request for the
service.
If we send a command with an invalid domain ID, would the FW reliably
report an error that we can recover from?
Yes for anything above this value, firmware returns invalid parameter
error. It's would be good to have that as a separate command instead
of getting it via DT. We already have that for OPPs and clocks. Just
this lacks that feature.
Otherwise, this looks ok. I'd just like to make sure I've understood
correctly.
Sure, thanks for the review.
--
Regards,
Sudeep
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