Re: [PATCH v4 12/19] arm64: dts: mediatek: mt8192-asurada: Couple VGPU and VSRAM_OTHER regulators
flat view
From: Chen-Yu Tsai <wenst@chromium.org>
Date: 2023-03-02 10:05:06
Also in:
linux-devicetree, linux-mediatek, lkml
On Wed, Mar 1, 2023 at 5:55 PM AngeloGioacchino Del Regno [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Add coupling for these regulators, as VSRAM_OTHER is used to power the GPU SRAM, and they have a strict voltage output relation to satisfy in order to ensure GPU stable operation. While at it, also add voltage constraint overrides for the GPU SRAM regulator "mt6359_vsram_others" so that we stay in a safe range of 0.75-0.80V. Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com> --- arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi | 9 +++++++++ 1 file changed, 9 insertions(+)diff --git a/arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi b/arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi index 8570b78c04a4..f858eca219d7 100644 --- a/arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi +++ b/arch/arm64/boot/dts/mediatek/mt8192-asurada.dtsi@@ -447,6 +447,13 @@ &mt6359_vrf12_ldo_reg { regulator-always-on; }; +&mt6359_vsram_others_ldo_reg { + regulator-min-microvolt = <750000>; + regulator-max-microvolt = <800000>; + regulator-coupled-with = <&mt6315_7_vbuck1>; + regulator-coupled-max-spread = <10000>;
Looking again at the downstream OPP table, it seems there's no voltage difference requirement. It only needs V_SRAM >= V_GPU. Same applies to MT8195. Looks like only MT8183 and MT8186 need V_SRAM - V_GPU >= 10000. Would setting max-spread to 0 work? I ask because with both regulator's maximum voltage set to 0.8V, there's no way we can reach the highest OPP. ChenYu
quoted hunk ↗ jump to hunk
+}; + &mt6359_vufs_ldo_reg { regulator-always-on; };@@ -1411,6 +1418,8 @@ mt6315_7_vbuck1: vbuck1 { regulator-max-microvolt = <800000>; regulator-enable-ramp-delay = <256>; regulator-allowed-modes = <0 1 2>; + regulator-coupled-with = <&mt6359_vsram_others_ldo_reg>; + regulator-coupled-max-spread = <10000>; }; }; }; --2.39.2
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