Re: [PATCH 1/3] dt: cpufreq: brcm: New binding document for brcm-avs-cpufreq
From: Rob Herring <robh@kernel.org>
Date: 2016-08-16 13:17:01
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On Fri, Aug 12, 2016 at 04:25:29PM -0700, Markus Mayer wrote:
quoted hunk ↗ jump to hunk
Add the binding document for the new brcm-avs-cpufreq driver. Signed-off-by: Markus Mayer <mmayer@broadcom.com> --- .../bindings/cpufreq/brcm-avs-cpufreq.txt | 84 ++++++++++++++++++++++ MAINTAINERS | 7 ++ 2 files changed, 91 insertions(+) create mode 100644 Documentation/devicetree/bindings/cpufreq/brcm-avs-cpufreq.txtdiff --git a/Documentation/devicetree/bindings/cpufreq/brcm-avs-cpufreq.txt b/Documentation/devicetree/bindings/cpufreq/brcm-avs-cpufreq.txt new file mode 100644 index 0000000..707ebe5 --- /dev/null +++ b/Documentation/devicetree/bindings/cpufreq/brcm-avs-cpufreq.txt@@ -0,0 +1,84 @@ +Broadcom AVS CPUfreq driver +=========================== + +This driver provides voltage and frequency scaling on Broadcom SoCs using
Bindings describe h/w (or firmware interfaces) not drivers. CPUFreq is a Linux term. Please re-word.
+the AVS firmware with DVFS support. The AVS firmware is running on its own +co-processor. The driver supports both uniprocessor (UP) and symmetric +multiprocessor (SMP) systems which share clock and voltage across all CPUs. + +Actual voltage and frequency scaling is done solely by the AVS firmware. +This driver does not change frequency or voltage itself. It provides a +standard CPUfreq interface to the rest of the kernel and to userland. It +interfaces with the AVS firmware to effect the requested changes and to +report back the current system status in a way that is expected by existing +tools. + +This driver requires two DT nodes. One node (brcm,avs-cpu-data-mem) +references the mailbox register used to communicate with the AVS CPU. The +second node (brcm,avs-cpu-l2-intr) is required to trigger an interrupt on +the AVS CPU. The interrupt tells the AVS CPU that it needs to process a +command sent to it by this driver. Interrupting the AVS CPU is mandatory for +commands to be processed.
The mailbox and interrupt to the AVS CPU are only for DVFS?