From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 B5D302D839C; Thu, 9 Apr 2026 13:35:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775741752; cv=none; b=IWMJbtXskyJcD6aoKdeiYrM/u6DVoFbM5WEK3X0Asac7zWY7qZ1Y+mielIalLFz3bYcJjjIL1PXDV5+1VLKVnOcJQO5rzC49vOmhSrLWRUcJ2G25wZvWq/D8Pdr1V2FpzYTc0JyoC3NvSjmKWJkwlGG2aukQyQV3yFlCZJMBYdc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775741752; c=relaxed/simple; bh=MWnfDUX5Bn1amz9RWj+IvqpmjxnGH9WloQN74pV7aos=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Jyv9cUv73nfTQTJ0LbFV8h4eQ/PbTITi10C2xZH/THPzgg12pDYjBaaHjNNbO9IoRAEeB7WJYXA1Dd01LQ9pY+UsYbacKzWp6KN7Ylb3WqD/xTOmHnabJwv5SrvmRETBSsC+ZP4QRi/3o4yXlvQnWFa45w11ZjP/aaHTYtjDQj4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ir/bjUW9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ir/bjUW9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 24461C4CEF7; Thu, 9 Apr 2026 13:35:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775741752; bh=MWnfDUX5Bn1amz9RWj+IvqpmjxnGH9WloQN74pV7aos=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ir/bjUW9ThRhaZ203luNRVUsqGSeIUoUU8tPBLVV5ANuPqk/k7JlZVBb/Ns8U9dMB HJGs52+D01DoLh7gVyZTGuF4Ru1SNXfCPC3SMyXPx5vAMLF7qNJNEvQVI20VF6MglW iudkSFtfG4LeyqvRYqyLTYcaAL1KcvxJElPrmwsOg803b6DOdXu4CIs022WwhP0ytJ lBvCwRfx89GEbfJAJ6bsIHoWZUcdA8huRgoy9r7P4uJM7upGKGrMcu+dJs0UB3mRWN GQ3RPgwmWuSzJFx7RE91wPxdYcsd8LWR0JlQktEOlDoVSCT6mAHEiCIr8de//yssjs Vc+nGmeI0QGEQ== Date: Thu, 9 Apr 2026 08:35:48 -0500 From: Bjorn Andersson To: Ayushi Makhija Cc: konrad.dybcio@linaro.org, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, dmitry.baryshkov@linaro.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, quic_rajeevny@quicinc.com, quic_vproddut@quicinc.com Subject: Re: [PATCH] arm64: dts: qcom: sm8750-mtp: Set sufficient voltage for panel nt37801 Message-ID: References: <20260323102229.1546504-1-quic_amakhija@quicinc.com> <75d22f54-eb55-4e55-9582-5b407f41ee81@quicinc.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <75d22f54-eb55-4e55-9582-5b407f41ee81@quicinc.com> On Thu, Apr 09, 2026 at 11:14:10AM +0530, Ayushi Makhija wrote: > On 3/26/2026 9:28 PM, Bjorn Andersson wrote: > > On Thu, Mar 26, 2026 at 03:06:52PM +0530, Ayushi Makhija wrote: > >> On 3/24/2026 7:34 AM, Bjorn Andersson wrote: > >>> On Mon, Mar 23, 2026 at 03:52:29PM +0530, Ayushi Makhija wrote: > >>>> The NT37801 Sepc V1.0 chapter "5.7.1 Power On Sequence" states > >>>> VDDI=1.65V~1.95V, so set sufficient voltage for panel nt37801. > >>>> > >>> > >>> Please add Fixes: tag. > >>> > >> > >> Hi Bjorn, > >> > >> Sure, will add in new patchset. > >> > >>>> Signed-off-by: Ayushi Makhija > >>> > >>> Please start using your oss.qualcomm.com address. > >>> > >>>> --- > >>>> arch/arm64/boot/dts/qcom/sm8750-mtp.dts | 2 +- > >>>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>>> > >>>> diff --git a/arch/arm64/boot/dts/qcom/sm8750-mtp.dts b/arch/arm64/boot/dts/qcom/sm8750-mtp.dts > >>>> index 3837f6785320..6ba4e69bf377 100644 > >>>> --- a/arch/arm64/boot/dts/qcom/sm8750-mtp.dts > >>>> +++ b/arch/arm64/boot/dts/qcom/sm8750-mtp.dts > >>>> @@ -462,7 +462,7 @@ vreg_l11b_1p0: ldo11 { > >>>> > >>>> vreg_l12b_1p8: ldo12 { > >>>> regulator-name = "vreg_l12b_1p8"; > >>>> - regulator-min-microvolt = <1200000>; > >>>> + regulator-min-microvolt = <1650000>; > >>> > >>> Are you sure it's not supposed to be 1.8V, given the name of the rail? > >>> > >>> Regards, > >>> Bjorn > >> > >> There was already discussion regarding the minimum voltage for this regulator on sm8550 target > >> on other upstream patch. > >> > >> Link: https://lore.kernel.org/all/aQQdQoCLeKhYtY7W@yuanjiey.ap.qualcomm.com/ > >> > >> This values is according to the NT37801 panel sec > >> "The NT37801 Sepc V1.0 chapter "5.7.1 Power On Sequence" states > >> VDDI=1.65V~1.95V." > >> > > > > Yes, so the panel requires 1.65V, so regulator-min-microvolt needs to be > > at least that. But regulator-min-microvolt should account for all the > > consumers of the rail, are there any others? > > > > Which leads me to my question, the people designing the board named the > > rail VREG_L12B_1P8 in the schematics, why didn't they name it > > VREG_L12B_1P65? > > > > Please check all the consumers and make the regulator-min-microvolt work > > for all of them - if that's 1.65V, then your change is good. > > > > Regards, > > Bjorn > > Hi Bjorn, > > There is only one consumer of VREG_L12B_1P8 rail, i.e. NT37801 panel. > So regulator-min-microvolt as 1.65V should be fine for VREG_L12B_1P8 rail. > Had to look it up myself. MTP power grid says it should be 1.8V. Thank you, Bjorn > Thanks, > Ayushi >