linux-kernel - Re: [PATCH v2] ARM: dts: sun8i: add opp-v2 table for A33

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Date:   Mon, 19 Dec 2016 15:30:10 +0100
From:   Quentin Schulz <quentin.schulz@...e-electrons.com>
To:     Icenowy Zheng <icenowy@...c.xyz>, Chen-Yu Tsai <wens@...e.org>,
        Maxime Ripard <maxime.ripard@...e-electrons.com>
Cc:     Hans de Goede <hdegoede@...hat.com>,
        devicetree <devicetree@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-clk <linux-clk@...r.kernel.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>
Subject: Re: [PATCH v2] ARM: dts: sun8i: add opp-v2 table for A33

On 19/12/2016 15:06, Icenowy Zheng wrote:
> 
> 
> 19.12.2016, 16:54, "Chen-Yu Tsai" <wens@...e.org>:
>> On Mon, Dec 19, 2016 at 4:46 PM, Maxime Ripard
>> <maxime.ripard@...e-electrons.com> wrote:
>>>  On Fri, Dec 16, 2016 at 02:27:54AM +0800, Icenowy Zheng wrote:
>>>>  An operating point table is needed for the cpu frequency adjusting to
>>>>  work.
>>>>
>>>>  The operating point table is converted from the common value in
>>>>  extracted script.fex from many A33 board/tablets.
>>>>
>>>>  Signed-off-by: Icenowy Zheng <icenowy@...c.xyz>
>>>>  ---
>>>>  Changes since v1:
>>>>  - Fix format problem (blank lines).
>>>>  - Removed the 1.344GHz operating point, as it's overvoltage and overclocked.
>>>>
>>>>  This patch depends on the following patchset:
>>>>
>>>>  http://lists.infradead.org/pipermail/linux-arm-kernel/2016-December/473962.html
>>>>
>>>>  It's the v2 of the [PATCH 4/6] in this patchset.
>>>>
>>>>  I think this operating point table may also apply to A23, as there's no
>>>>  difference except the points over 1.2GHz between A23 and A33's stock dvfs table.
>>>>
>>>>  But as A23 CCU may not have the necessary fixes, I won't add the table to A23
>>>>  now.
>>>>
>>>>  Chen-Yu, could you test the CCU fixes I described in the patchset above on A23,
>>>>  then test this operating points table?
>>>>
>>>>  If it's necessary, you can send out the CCU fixes and add one more patch that
>>>>  moves this opp-v2 table to sun8i-a23-a33.dtsi .
>>>>
>>>>   arch/arm/boot/dts/sun8i-a33.dtsi | 35 +++++++++++++++++++++++++++++++++++
>>>>   1 file changed, 35 insertions(+)
>>>>
>>>>  diff --git a/arch/arm/boot/dts/sun8i-a33.dtsi b/arch/arm/boot/dts/sun8i-a33.dtsi
>>>>  index 504996cbee29..0f5b2af72981 100644
>>>>  --- a/arch/arm/boot/dts/sun8i-a33.dtsi
>>>>  +++ b/arch/arm/boot/dts/sun8i-a33.dtsi
>>>>  @@ -46,7 +46,42 @@
>>>>   #include <dt-bindings/dma/sun4i-a10.h>
>>>>
>>>>   / {
>>>>  + cpu0_opp_table: opp_table0 {
>>>>  + compatible = "operating-points-v2";
>>>>  + opp-shared;
>>>>  +
>>>>  + opp@...000000 {
>>>>  + opp-hz = /bits/ 64 <648000000>;
>>>>  + opp-microvolt = <1040000>;
>>>>  + clock-latency-ns = <244144>; /* 8 32k periods */
>>>>  + };
>>>>  +
>>>>  + opp@...000000 {
>>>>  + opp-hz = /bits/ 64 <816000000>;
>>>>  + opp-microvolt = <1100000>;
>>>>  + clock-latency-ns = <244144>; /* 8 32k periods */
>>>>  + };
>>>>  +
>>>>  + opp@...8000000 {
>>>>  + opp-hz = /bits/ 64 <1008000000>;
>>>>  + opp-microvolt = <1200000>;
>>>>  + clock-latency-ns = <244144>; /* 8 32k periods */
>>>>  + };
>>>>  +
>>>>  + opp@...0000000 {
>>>>  + opp-hz = /bits/ 64 <1200000000>;
>>>>  + opp-microvolt = <1320000>;
>>>>  + clock-latency-ns = <244144>; /* 8 32k periods */
>>>>  + };
>>>>  + };
>>>>  +

Also, there are a lot more operating points for the A33, see:
https://github.com/QSchulz/linux/blob/v4.9-rc4_adc_a31_v7/cpufreq_a33/arch/arm/boot/dts/sun8i-a33.dtsi#L323-L340

They are present in the Allwinner Linux source code and in the fex of
all A33-based boards.

Is there a reason for not adding all opp?

Quentin

-- 
Quentin Schulz, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com