From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 17 Jun 2019 10:48:39 +0100 From: Lorenzo Pieralisi Subject: Re: [PATCH V4 27/28] PCI: tegra: Add support for GPIO based PERST# Message-ID: <20190617094839.GE18020@e121166-lin.cambridge.arm.com> References: <20190613152404.GB30445@e121166-lin.cambridge.arm.com> <20190614143222.GB23116@e121166-lin.cambridge.arm.com> <1508173d-0ecc-f498-6ab2-78a718086b35@nvidia.com> <20190614145023.GA24588@e121166-lin.cambridge.arm.com> <20190614152304.GK15526@ulmo> <20190614155934.GA28253@e121166-lin.cambridge.arm.com> <51e4ae62-f842-1d2f-fbca-0b2063dd53a6@nvidia.com> <20190614165353.GB30511@e121166-lin.cambridge.arm.com> <1c662f82-8329-5e1b-58bf-b2fe1643adb0@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1c662f82-8329-5e1b-58bf-b2fe1643adb0@nvidia.com> To: Manikanta Maddireddy Cc: Thierry Reding , bhelgaas@google.com, robh+dt@kernel.org, mark.rutland@arm.com, jonathanh@nvidia.com, vidyas@nvidia.com, linux-tegra@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org List-ID: On Fri, Jun 14, 2019 at 10:53:13PM +0530, Manikanta Maddireddy wrote: [...] > > Ok. My point then is that you have no way to enforce this requirement on > > platforms that actually need it, I do not even know if there is a > > way you can do it (I was thinking along the lines of using a > > compatible string to detect whether the GPIO #PERST reset is mandatory) > > but maybe this is not even a SOC property. > > > > Maybe what I am asking is overkill, I just wanted to understand. > > > > I was just asking a question to understand how you handle the case > > where a GPIO pin definition is missing in DT for a platform that > > actually needs it, the driver will probe but nothing will work. > > > > It would be good to describe this and capture it in the commit log. > > > > Thanks, > > Lorenzo > > I can't think of a easy way to enforce this requirement. As you said > compatible string is per SOC, so we can't use it for a platform. > This issue is present on only one platform, so it is hard to miss the > DT property. That is the reason for publishing this patch with out this > enforcement in driver. > > I thought for changing PERST# to GPIO for all platform, but testing is > a tedious job. Also I don't have Tegra20 and Tegra30 platforms. I can't help with that. > Do you want me to drop the patch or update the limitation in the commit > log? It is Thierry's call, if he is OK with it fine by me, please do update the commit log, it will help everybody understand. Lorenzo