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

On Wed, Jul 26, 2017 at 3:16 PM, Icenowy Zheng [off-list ref] wrote:

于 2017年7月26日 GMT+08:00 下午3:08:06, Chen-Yu Tsai [off-list ref] 写到:

quoted

On Sun, Jul 23, 2017 at 6:27 PM, Icenowy Zheng [off-list ref] wrote:

quoted

From: Ondrej Jirman <redacted>

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 <redacted>
[Icenowy: Enable DVFS in this patch, slight changes and change commit
 message]
Signed-off-by: Icenowy Zheng <icenowy@aosc.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

quoted

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.

Even then you should still leave a note describing why we allow
voltages below the recommended range.

ChenYu

quoted

Otherwse

quoted

+               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).

ChenYu

quoted

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