From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from madrid.collaboradmins.com (madrid.collaboradmins.com [46.235.227.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F2F814A07; Wed, 13 Mar 2024 14:36:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=46.235.227.194 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710340615; cv=none; b=lGraK+qijlyPcSHMvPS0K8le/63rAFsBxgc2bI8K4VKE6GZ/b/p4QkYGOt/cvMZQhunmZySPzhiOtOFGtirxQzLtgyTMplPVN90czdnEr34mnVoJrPeOTnm5R46MQdW6YrpjgPeMhBKYvLRjvyA6vJhbA9Jttm16SCRIdSh5TGE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710340615; c=relaxed/simple; bh=aBISMkyzcuXC4tndXkf0VYcmI9kprzzcj/ehlqHMdAQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=CrJxc8VdFGc0tfJXf3KQviAC2BKw5mQ3bkbX6pT2yuBOOXbc9CNtxX62X/xLdXRGFosMuDgRZGbUBDfRdlsv/AkM3pGQhwPF6U4BTb7NVvpEzf7hL7vTpIO55dYyYh3TnRt8hVVX7o6L1fvJt0osuoQsgsEqoZ4uknNANYUvRSo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=wV45Rr4v; arc=none smtp.client-ip=46.235.227.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="wV45Rr4v" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1710340612; bh=aBISMkyzcuXC4tndXkf0VYcmI9kprzzcj/ehlqHMdAQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=wV45Rr4voGJHrKXICE5+Eye7hrS2Pjf//lLfPMsweUmrMtaGowHMg8I1ftEp0aoc6 vVBZcOLf4o11Mg5tTnufw6SyfR0TmnYh7euYN5U/mbmh4D+veduK3L1cVcQzJtfwf8 3xTrl9JpUKtiEXdqBnujwEENhAYfYbBGvY78+vuV4+LxRKjiguO64XhrhCNeecyRoN QZR3ZhhDixM01wErO5qokiWMlKaRyx4SfSpnoi9s4eVgvGyGB75R5QPDv7h5kpVTPk 4auppMOqkpTTs4wsJ/OuuvWTViAs6wdbnrHFPzTu7gtp0SfvfQWyasvBTJhcjCEcls O/G14egc519mg== Received: from [100.113.186.2] (cola.collaboradmins.com [195.201.22.229]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: kholk11) by madrid.collaboradmins.com (Postfix) with ESMTPSA id 9A15437813C4; Wed, 13 Mar 2024 14:36:51 +0000 (UTC) Message-ID: Date: Wed, 13 Mar 2024 15:36:50 +0100 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] arm64: dts: mediatek: mt8192-asurada: Update min voltage constraint for Vgpu Content-Language: en-US To: Pin-yen Lin , Matthias Brugger Cc: Chen-Yu Tsai , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, =?UTF-8?Q?N=C3=ADcolas_F_=2E_R_=2E_A_=2E_Prado?= , devicetree@vger.kernel.org References: <20240313135157.98989-1-treapking@chromium.org> From: AngeloGioacchino Del Regno In-Reply-To: <20240313135157.98989-1-treapking@chromium.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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 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 :-) 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>;