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From: Bjorn Helgaas <helgaas@kernel.org>
To: Jian Yang <jian.yang@mediatek.com>
Cc: "Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Jianjun Wang" <jianjun.wang@mediatek.com>,
	"Rob Herring" <robh@kernel.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"Ryder Lee" <ryder.lee@mediatek.com>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
	devicetree@vger.kernel.org,
	Project_Global_Chrome_Upstream_Group@mediatek.com,
	chuanjia.liu@mediatek.com, jieyy.yang@mediatek.com,
	qizhong.cheng@mediatek.com, rex-bc.chen@mediatek.com,
	david-yh.chiu@mediatek.com
Subject: Re: [PATCH 1/2] PCI: mediatek-gen3: Add power and reset control feature for downstream component
Date: Wed, 11 Jan 2023 16:14:19 -0600	[thread overview]
Message-ID: <20230111221419.GA1710905@bhelgaas> (raw)
In-Reply-To: <20230111032542.20306-2-jian.yang@mediatek.com>

Hi,

On Wed, Jan 11, 2023 at 11:25:41AM +0800, Jian Yang wrote:
> From: "jian.yang" <jian.yang@mediatek.com>
> 
> Make MediaTek's controller driver capable of controlling power
> supplies and reset pin of a downstream component in power-on and
> power-off flow.
> 
> Some downstream components (e.g., a WIFI chip) may need an extra
> reset other than of PERST# and their power supplies, depending on
> the requirements of platform, may need to controlled by their
> parent's driver. To meet the requirements described above, I add this
> feature to MediaTek's PCIe controller driver as a optional feature.

Is this delay (dsc-reset-msleep) specific to a device downstream from
the MediaTek controller, not to the MediaTek controller itself?  If
so, it sounds like it should be a generic value that could be used by
other drivers, too.

How do you determine the value?  If there's some PCIe spec that
determines this, please include a citation to it.  

Bjorn

  reply	other threads:[~2023-01-11 22:14 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-11  3:25 [PATCH 0/2] PCI: mediatek-gen3: Support controlling power supplies Jian Yang
2023-01-11  3:25 ` [PATCH 1/2] PCI: mediatek-gen3: Add power and reset control feature for downstream component Jian Yang
2023-01-11 22:14   ` Bjorn Helgaas [this message]
2023-02-03  3:27     ` Jian Yang (杨戬)
2023-01-11  3:28 [PATCH 0/2] PCI: mediatek-gen3: Support controlling power and reset of downstream componennt Jian Yang
2023-01-11  3:28 ` [PATCH 1/2] PCI: mediatek-gen3: Add power and reset control feature for downstream component Jian Yang

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