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 CE3C330B53A; Wed, 17 Sep 2025 10:10:40 +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=1758103840; cv=none; b=qqxxwt3J0Bbhw5ddjJdTwCONJm/NSR6BvjSF/+jsP9infQGTz7hR5bmiVOG7wwYcINVd4nx12+zo4weARK/VQ+T0R5OYhNu8Mwnlbf4/NZkepSOyUFuVcd+Kg+Eb98Hx6K/Qte7AHjR9UDf/WwJqbu08jXBM7nt14eBQiG1jNlI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758103840; c=relaxed/simple; bh=fxBhSVRS6bOcA+leORFJ7MYoYKjXLh84X9wt1eKH1Rs=; h=From:To:Cc:In-Reply-To:References:Subject:Message-Id:Date: MIME-Version:Content-Type; b=Hy1bSFc5LgsklH5YvKyYIeWkQEz+mHsgYCWjHzHRZmZLsftVmbSn6mkjCmMU7gS4nhmSNmsvcuz7ayuPZ7/OSpe9zgDF9/QN5YjQymvyZ6M8ymDVQlZya/PlDaiWr0I5rVEKj6EF1brJpHMpooLsg+dKIqvoI3KuBZ+eliz4Hb0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dCxD/Qso; 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="dCxD/Qso" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7448C4CEF0; Wed, 17 Sep 2025 10:10:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758103840; bh=fxBhSVRS6bOcA+leORFJ7MYoYKjXLh84X9wt1eKH1Rs=; h=From:To:Cc:In-Reply-To:References:Subject:Date:From; b=dCxD/QsoJpVub0T44kKAemN+6+9BP0qsd0yiyTWphn1SNJpmT768/IGiPvbsLlFr8 2CxRJ4ZeSSyq6YfI9tzCq9QsLnAgglEWRbaBMfJMNTERD6+u1PSyPAk8NhEqEZ+9vd qHt9e6Dv4HnQR+IKixDefLcpMI0mz+uW4Wo5e8Wkx2CU5U64DvpxQiHFN/KslkbcXD 5dEgNRDMZv2bRtdKY26PtAGgzUuu3+7917+/93PGWrgluhjUJXI6JTeiT8GMBDBzvV 0a1MzKpad/RIc/jkG7a+AApACp5bh8tJC/ALL13zyHsq3rtTs/tAVPnFyi4447h3mg z1nBtV3JIRO5g== From: Manivannan Sadhasivam To: Lorenzo Pieralisi , =?utf-8?q?Krzysztof_Wilczy=C5=84ski?= , Rob Herring , Bjorn Helgaas , Bartosz Golaszewski , Saravana Kannan , Manivannan Sadhasivam Cc: linux-pci@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Krishna Chaitanya Chundru , Brian Norris , Bjorn Helgaas In-Reply-To: <20250912-pci-pwrctrl-perst-v3-0-3c0ac62b032c@oss.qualcomm.com> References: <20250912-pci-pwrctrl-perst-v3-0-3c0ac62b032c@oss.qualcomm.com> Subject: Re: (subset) [PATCH v3 0/4] PCI/pwrctrl: Allow pwrctrl framework to control PERST# if available Message-Id: <175810383525.37722.6338178642788441926.b4-ty@kernel.org> Date: Wed, 17 Sep 2025 15:40:35 +0530 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Mailer: b4 0.14.2 On Fri, 12 Sep 2025 14:05:00 +0530, Manivannan Sadhasivam wrote: > This series is the proper version for toggling PERST# from the pwrctrl > framework after the initial RFC posted earlier [1]. > > Problem statement > ================= > > Pwrctrl framework is intented to control the supplies to the components on the > PCI bus. However, if the platform supports the PERST# signal, it should be > toggled as per the requirements in the electromechanical specifications like > PCIe CEM, Mini, and M.2. Since the pwrctrl framework is controlling the power > supplies, it should also toggle PERST# as per the requirements in the above > mentioned specifications. Right now, it is just controlling the power to the > components and rely on controller drivers to toggle PERST#, which goes against > the specs. For instance, controller drivers will deassert PERST# even before the > pwrctrl driver enables the supplies. This causes the device to see PERST# > deassert immediately after power on, thereby violating the delay requirements in > the PCI Electromechanical specs. > > [...] Applied, thanks! [2/4] PCI: qcom: Move host bridge 'phy' and 'reset' pointers to struct qcom_pcie_port commit: af8df709bf365f5583d31091280354e1ef0b201f Best regards, -- Manivannan Sadhasivam