linux-kernel - Re: [linux-sunxi] [PATCH 10/10] ARM: dts: sun8i: Add SY8106A regulator to Orange Pi PC

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Message-ID: <82507f40a1ddba8517cf09f51d3afa33@aosc.io>
Date:   Wed, 26 Jul 2017 15:36:27 +0800
From:   icenowy@...c.io
To:     wens@...e.org
Cc:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Maxime Ripard <maxime.ripard@...e-electrons.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-clk <linux-clk@...r.kernel.org>,
        "open list:THERMAL" <linux-pm@...r.kernel.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>,
        Ondrej Jirman <megous@...ous.com>
Subject: Re: [linux-sunxi] [PATCH 10/10] ARM: dts: sun8i: Add SY8106A
 regulator to Orange Pi PC

在 2017-07-26 15:30，Chen-Yu Tsai 写道：
> On Wed, Jul 26, 2017 at 3:16 PM, Icenowy Zheng <icenowy@...c.io> wrote:
>> 
>> 
>> 于 2017年7月26日 GMT+08:00 下午3:08:06, Chen-Yu Tsai <wens@...e.org> 写到:
>>> On Sun, Jul 23, 2017 at 6:27 PM, Icenowy Zheng <icenowy@...c.io> 
>>> wrote:
>>>> From: Ondrej Jirman <megous@...ous.com>
>>>> 
>>>> Add SY8106A regulator to r_i2c bus and enable the r_i2c bus on
>>>> Orange Pi PC, then set the power supply of the ARM cores to this
>>>> regulator, in order to enable DVFS.
>>>> 
>>>> Signed-off-by: Ondrej Jirman <megous@...ous.com>
>>>> [Icenowy: Enable DVFS in this patch, slight changes and change 
>>>> commit
>>>>  message]
>>>> Signed-off-by: Icenowy Zheng <icenowy@...c.io>
>>>> ---
>>>>  arch/arm/boot/dts/sun8i-h3-orangepi-pc.dts | 19 +++++++++++++++++++
>>>>  1 file changed, 19 insertions(+)
>>>> 
>>>> diff --git a/arch/arm/boot/dts/sun8i-h3-orangepi-pc.dts
>>> b/arch/arm/boot/dts/sun8i-h3-orangepi-pc.dts
>>>> index 998b60f8d295..d855f8b6254e 100644
>>>> --- a/arch/arm/boot/dts/sun8i-h3-orangepi-pc.dts
>>>> +++ b/arch/arm/boot/dts/sun8i-h3-orangepi-pc.dts
>>>> @@ -98,6 +98,10 @@
>>>>         status = "okay";
>>>>  };
>>>> 
>>>> +&cpu0 {
>>>> +       cpu-supply = <&reg_sy8106a>;
>>>> +};
>>>> +
>>>>  &ehci0 {
>>>>         status = "okay";
>>>>  };
>>>> @@ -160,6 +164,21 @@
>>>>         };
>>>>  };
>>>> 
>>>> +&r_i2c {
>>>> +       status = "okay";
>>>> +
>>>> +       reg_sy8106a: regulator@65 {
>>>> +               compatible = "silergy,sy8106a";
>>>> +               reg = <0x65>;
>>>> +               regulator-name = "vdd-cpux";
>>>> +               regulator-min-microvolt = <1000000>;
>>> 
>>> According to the H3 datasheet, the minimum voltage is 1.1V, not 1V.
>> 
>> But the Armbian OPP table for H3 contains several
>> OPP under 1.1V...
> 
> Can you provide a link?
> 
> If Armbian users have actually field tested this (a big if),
> then I would like to see some evidence of the SoC running
> stably at those OPPs with those lower voltages under full load.

See [1].

[1] 
https://github.com/armbian/build/blob/master/config/fex/orangepipc.fex#L736

> 
> Even then you should still leave a note describing why we allow
> voltages below the recommended range.
> 
> ChenYu
> 
>> 
>>> 
>>> Otherwse
>>> 
>>>> +               regulator-max-microvolt = <1400000>;
>>>> +               regulator-ramp-delay = <200>;
>>> 
>>> Is this an actual constraint of the SoC? Or is it a characteristic
>>> of the regulator? If it is the latter, it belongs in the driver.
>>> AFAIK the regulator supports varying the ramp delay (slew rate).

I don't know...

Maybe I should ask Ondrej?

>>> 
>>> ChenYu
>>> 
>>>> +               regulator-boot-on;
>>>> +               regulator-always-on;
>>>> +       };
>>>> +};
>>>> +
>>>>  &r_pio {
>>>>         leds_r_opc: led_pins@0 {
>>>>                 pins = "PL10";
>>>> --
>>>> 2.13.0
>>>>