[PATCH v2 1/2] Documentation: dt: add bindings for ti-cpufreq
From: robh@kernel.org (Rob Herring)
Date: 2016-09-19 21:14:00
Also in:
linux-devicetree, linux-omap, linux-pm
Possibly related (same subject, not in this thread)
- 2016-09-12 · Re: [PATCH v2 1/2] Documentation: dt: add bindings for ti-cpufreq · Dave Gerlach <hidden>
- 2016-09-08 · Re: [PATCH v2 1/2] Documentation: dt: add bindings for ti-cpufreq · Viresh Kumar <viresh.kumar@linaro.org>
- 2016-09-07 · Re: [PATCH v2 1/2] Documentation: dt: add bindings for ti-cpufreq · Dave Gerlach <hidden>
- 2016-09-07 · Re: [PATCH v2 1/2] Documentation: dt: add bindings for ti-cpufreq · Viresh Kumar <viresh.kumar@linaro.org>
- 2016-09-01 · [PATCH v2 1/2] Documentation: dt: add bindings for ti-cpufreq · Dave Gerlach <hidden>
On Wed, Aug 31, 2016 at 09:53:27PM -0500, Dave Gerlach wrote:
Add the device tree bindings document for the TI CPUFreq/OPP driver on AM33xx, AM43xx, DRA7, and AM57 SoCs. The operating-points-v2 binding allows us to provide an opp-supported-hw property for each OPP to define when it is available. This driver is responsible for reading and parsing registers to determine which OPPs can be selectively enabled based on the specific SoC in use by matching against the opp-supported-hw data.
Sorry, for the delay. Missed this somehow.
quoted hunk
Signed-off-by: Dave Gerlach <redacted> --- v1->v2: - Dropped all driver/linux specific documentation - Fixed some typos - Add new compatibles for each SoC family to match against - Switched to use am335x example to better demonstrate field one of opp-supported-hw. .../devicetree/bindings/cpufreq/ti-cpufreq.txt | 130 +++++++++++++++++++++ 1 file changed, 130 insertions(+) create mode 100644 Documentation/devicetree/bindings/cpufreq/ti-cpufreq.txtdiff --git a/Documentation/devicetree/bindings/cpufreq/ti-cpufreq.txt b/Documentation/devicetree/bindings/cpufreq/ti-cpufreq.txt new file mode 100644 index 000000000000..6276ae494121 --- /dev/null +++ b/Documentation/devicetree/bindings/cpufreq/ti-cpufreq.txt@@ -0,0 +1,130 @@ +TI CPUFreq and OPP bindings +================================ + +Certain TI SoCs, like those in the am335x, am437x, am57xx, and dra7xx +families support different OPPs depending on the silicon variant in use. +The ti_cpufreq driver can use revision and an efuse value from the SoC to +provide the OPP framework with supported hardware information. This is +used to determine which OPPs from the operating-points-v2 table get enabled +when it is parsed by the OPP framework. + +Required properties: +-------------------- +In 'cpus' nodes: +- operating-points-v2: Phandle to the operating-points-v2 table to use. +- ti,syscon-efuse: Syscon phandle, offset to efuse register, efuse register + mask, and efuse register shift to get the relevant bits + that describe OPP availability. +- ti,syscon-rev: Syscon and offset used to look up revision value on SoC.
These have nothing to do with a cpu, so they don't belong here. Maybe the first is a property of an OPP table, but the second certainly is not.
+ +In 'operating-points-v2' table: +- compatible: Should be + - 'operating-points-v2-ti-am3352-cpu' for am335x SoCs + - 'operating-points-v2-ti-am4372-cpu' for am43xx SoCs + - 'operating-points-v2-ti-dra7-cpu' for dra7xx/am57xx SoCs + +- opp-supported-hw: Two bitfields indicating: + 1. Which revision of the SoC the OPP is supported by + 2. Which eFuse bits indicate this OPP is available
I tend to think you should handle this with kernel code (bootloader really) fixing up the OPP table as necessary rather than putting in DT. Rob