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 63309302CDF; Wed, 26 Nov 2025 14:44:11 +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=1764168251; cv=none; b=D7K1kUMy2xVGiOaEWMOdFwE6z2VzLDdezaLXe2U/QGgFvqJg6WOPaM3v3oNT0gUEYtb/9nvPka7Jyyqc+IPNYxwTTYOYjwbT+7QrQY8kRB8FfM3SFVEhfsJNl6RqH+jPTlq8XVOgt3xw0CLkmnI5uk5ssTuAAVX18tO0aPrWj+o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764168251; c=relaxed/simple; bh=CaXdK+vzZdACfgHpBANqiwt7O2iyXlQl5re8FsK88co=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=dBmJVFrcmOV0pg0/aWfTSZHnqWD/ZWGE3DQrOosCQziADs1Sat36on9v8qYAsPWDHcWusdkyuLVNloeugkm45vJfy+6GsgXDL/5w4nK9yZhFZ8anlUVjZ+ttUWwCEKf6+Ji8KuBv9MtWW/IbYVii6V090e5/b1SBtA88NUjbSQc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ssx6gYoB; 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="Ssx6gYoB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C96B8C4CEF7; Wed, 26 Nov 2025 14:44:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764168250; bh=CaXdK+vzZdACfgHpBANqiwt7O2iyXlQl5re8FsK88co=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=Ssx6gYoBmcnMtyX1VwaoNqJ/PBMS9NEkbNm8RP2uOl0B6VQhn+duPP8p7OziVpHEH /vGRvFBUrt850rzDHIUGr80SxUGHpLsDxFAoRPPhpUohkCcKPY6PTqUR6dHTvcKMJ1 LWqc7Ss/wSHgp4ffrVoTfYeCXo/Gj7CbRMJw56n+4vY1GZHXYtK/etbsRKR5kFepXG zKERq7Bgc0TK9Narnaap9m6f4r+U+xKsEVt+GP8IPQ1uZtXZQVdehIDGDRWWRzMgMW OyS+BRsc1fdQOJIEtq/keFqx1RVT/kPV5Vwv7CrzGwKusHR1myhZHVwnp0QZnHlqFH 65HLeFzy03sIA== Date: Wed, 26 Nov 2025 08:44:09 -0600 From: Bjorn Helgaas To: Krishna Chaitanya Chundru Cc: andersson@kernel.org, robh@kernel.org, mani@kernel.org, krzk@kernel.org, linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, lpieralisi@kernel.org, kw@linux.com, conor+dt@kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree-spec@vger.kernel.org, quic_vbadigan@quicinc.com, lukas@wunner.de Subject: Re: [PATCH v3] schemas: pci: Document PCIe T_POWER_ON Message-ID: <20251126144409.GA2825768@bhelgaas> Precedence: bulk X-Mailing-List: devicetree-spec@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: <20251126103112.838549-1-krishna.chundru@oss.qualcomm.com> On Wed, Nov 26, 2025 at 04:01:12PM +0530, Krishna Chaitanya Chundru wrote: > From PCIe r7, sec 5.5.4 & Table 5-11 in sec 5.5.5 T_POWER_ON is the > minimum amount of time(in us) that each component must wait in L1.2.Exit > after sampling CLKREQ# asserted before actively driving the interface to > ensure no device is ever actively driving into an unpowered component and > these values are based on the components and AC coupling capacitors used > in the connection linking the two components. > > This property should be used to indicate the T_POWER_ON and drivers using > this property are responsible for parsing both the scale and the value of > T_POWER_ON to comply with the PCIe specification. Add space before open "(" above and in description below. > Signed-off-by: Krishna Chaitanya Chundru > --- > Changes in v2: > - Move the property to pci-device.yaml so that it will be applicable to > endpoint devices also (Mani). > - Use latest spec (Lukas) > - Link to v2: https://lore.kernel.org/all/20251110112947.2071036-1-krishna.chundru@oss.qualcomm.com/ > Changes in v1: > - Updated the commiit text (Mani). > - Link to v1: https://lore.kernel.org/all/20251110112550.2070659-1-krishna.chundru@oss.qualcomm.com/#t > > dtschema/schemas/pci/pci-device.yaml | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/dtschema/schemas/pci/pci-device.yaml b/dtschema/schemas/pci/pci-device.yaml > index ca094a0..4baab71 100644 > --- a/dtschema/schemas/pci/pci-device.yaml > +++ b/dtschema/schemas/pci/pci-device.yaml > @@ -63,6 +63,15 @@ properties: > description: GPIO controlled connection to WAKE# signal > maxItems: 1 > > + t-power-on-us: > + description: > + The minimum amount of time that each component must wait in > + L1.2.Exit after sampling CLKREQ# asserted before actively driving > + the interface to ensure no device is ever actively driving into an > + unpowered component. This value is based on the components and AC > + coupling capacitors used in the connection linking the two > + components(PCIe r7.0, sec 5.5.4). > + > required: > - reg > > -- > 2.34.1 >