Cc'ing few more people who were involved in opp-v2 discussions.
Guys, please take a closer look as this is the first user platform
that wants to extend opp-v2 bindings with platform specific stuff.
On 21-07-15, 12:33, Lee Jones wrote:
> Cc: devicetree@xxxxxxxxxxxxxxx
> Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx>
> ---
>
> Only submitting the binding document as requested by Viresh.
>
> v2 => v3:
> - Using OPP v2
> - Moved OPPs out of the CPU node into their own one
> - Using generic 'opp-hz' property
>
> .../devicetree/bindings/cpufreq/cpufreq-st.txt | 77 ++++++++++++++++++++++
> 1 file changed, 77 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
>
> diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
> new file mode 100644
> index 0000000..a478eec
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-st.txt
These are used by cpufreq, but they aren't really cpufreq bindings.
These are opp bindings and must present at:
Documentation/devicetree/bindings/power/opp/st.txt and we should move
opp.txt in that folder as well..
> @@ -0,0 +1,77 @@
> +Binding for ST's CPUFreq driver
> +===============================
> +
> +Required properties [for working voltage scaling]:
> +-------------------------------------------------
> +
> +Located in CPU's node:
I hope below registers are used to define which OPPs are valid for the
CPU and so shouldn't these be present under opp node instead of CPU?
> +- st,syscfg : Phandle to Major number register
> + First cell: offset to major number
> +- st,syscfg-eng : Phandle to Minor number and Pcode registers
> + First cell: offset to process code
> + Second cell: offset to minor number
> +
> +Located in 'cpu0-opp-list' node [to be provided ONLY by the bootloader]:
> +
> + - opp{1..N} : Each 'oppX' subnode will contain the following properties:
> + - opp-hz : CPU frequency [Hz] for this OPP
Not sure if you are required to re define it. In case you want to, the
please add a link here to the bindings that define it. So that we
don't think they are newer bindings.
> + - st,avs : List of available voltages [uV] indexed by process code
> + - st,cuts : Cut version this OPP is suitable for [0xFF means ALL]
> + - st,substrate : Substrate version this OPP is suitable for [0xFF means ALL]
@Stephen: Any idea if these can be relevant for other platforms and we
can move them to generic bindings?
> +WARNING: The cpu0-opp-list will be provided by the bootloader. Do not attempt to
> + artificially synthesise the cpu0-opp-list node or any of its descendants.
> + They are very platform specific and may damage the hardware if created
> + incorrectly.
> +
> +Required properties [if voltage scaling properties are missing]:
> +-------------------------------------------------------------------
> +
> +Located in CPU's node:
> +
> +- operating-points : [See: ../power/opp.txt]
> +
> +Example [safe]:
> +--------------
> +
> +cpus {
> + cpu@0 {
> + /* kHz uV */
> + operating-points = <1500000 0
> + 1200000 0
> + 800000 0
> + 500000 0>;
> + };
> +};
Why do you want to keep these as well?
> +Example [unsafe]:
> +----------------
> +
> +cpus {
> + cpu@0 {
> + st,syscfg = <&syscfg [major_offset]>;
> + st,syscfg-eng = <&syscfg_eng [pcode_offset] [minor_offset]>;
> + operating-points-v2 = <&cpu0_opp_list>;
> + };
> +};
> +
> +/* ############################################################ */
> +/* # WARNING: Do not attempt to copy/replicate this node, # */
> +/* # it is only to be supplied by the bootloader !!! # */
> +/* ############################################################ */
> +cpu0-opp-list {
> + compatible = "operating-points-v2-sti";
> + opp0 {
> + opp-hz = <1200000000>;
> + st,avs = <1110 1150 1100 1080 1040 1020 980 930>;
> + st,substrate = <0xff>;
> + st,cuts = <0xff>;
> + };
> + opp1 {
> + opp-hz = <1500000000>;
> + st,avs = <1200 1200 1200 1200 1170 1140 1100 1070>;
> + st,substrate = <0xff>;
> + st,cuts = <0x2>;
> + };
> +};
--
viresh
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