Il 14/03/24 10:59, Pin-yen Lin ha scritto:
Hi Angelo,
On Wed, Mar 13, 2024 at 10:36 PM AngeloGioacchino Del Regno <
angelogioacchino.delregno@xxxxxxxxxxxxx> wrote:
Il 13/03/24 14:51, Pin-yen Lin ha scritto:
Although the minimum voltage listed on the GPU OPP table is 606250 uV,
the actual requested voltage could be even lower when the MTK Smart
Voltage Scaling (SVS) driver is enabled.
Set the minimum voltage to 300000 uV because it's supported by the
regulator.
Fixes: 3183cb62b033 ("arm64: dts: mediatek: asurada: Add SPMI
regulators")
Signed-off-by: Pin-yen Lin <treapking@xxxxxxxxxxxx>
Okay, that makes sense, I agree.
...but.
The datasheet never mentions 0.3V as vmin - infact, it does mention that
the
vsel is selected as (0V +) 6250 * Vsel, but the brief spec says that for
the
standard configuration (in terms of HW), the Vmin is 0.4V and not 0.3.
Reading through makes me think that it's not much about the buck providing
an
unstable output, but more about it starting to become inefficient under
that
value.
This means that it is sensible to set, instead:
regulator-min-microvolt = <400000>;
Also, this is repeated on multiple platforms: can you please perform the
same
change also on MT8183, MT8186 and MT8195?
P.S.: For MT6358, the Vmin for VGPU is 0.5V :-)
Thanks for checking! I'll update the values on other platforms as well.
I assume that we also want to update other mt6315 nodes listing 300000 uV
as the min voltage, so I'll update them as well.
Yes, didn't notice that, nice catch. Please do!
Cheers,
Angelo
---
arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi
b/arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi
index 43d80334610a..5cc5100a7c40 100644
--- a/arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi
@@ -1448,7 +1448,7 @@ regulators {
mt6315_7_vbuck1: vbuck1 {
regulator-compatible = "vbuck1";
regulator-name = "Vgpu";
- regulator-min-microvolt = <606250>;
+ regulator-min-microvolt = <300000>;
regulator-max-microvolt = <800000>;
regulator-enable-ramp-delay = <256>;
regulator-allowed-modes = <0 1 2>;
