From mboxrd@z Thu Jan 1 00:00:00 1970 From: swarren@wwwdotorg.org (Stephen Warren) Date: Fri, 09 Mar 2012 09:47:11 -0700 Subject: [PATCH 11/11] ARM: tegra: pcie: Add device tree support In-Reply-To: <20120309063115.GA25208@avionic-0098.mockup.avionic-design.de> References: <1331218291-16119-1-git-send-email-thierry.reding@avionic-design.de> <1331218291-16119-12-git-send-email-thierry.reding@avionic-design.de> <4F59253D.7070100@wwwdotorg.org> <20120309063115.GA25208@avionic-0098.mockup.avionic-design.de> Message-ID: <4F5A340F.6080303@wwwdotorg.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 03/08/2012 11:31 PM, Thierry Reding wrote: > * Stephen Warren wrote: >> On 03/08/2012 07:51 AM, Thierry Reding wrote: >>> This commit adds support for instantiating the Tegra PCIe controller >>> from a device tree. >>> >>> Signed-off-by: Thierry Reding >> >>> diff --git a/Documentation/devicetree/bindings/pci/tegra-pcie.txt b/Documentation/devicetree/bindings/pci/tegra-pcie.txt >> >>> +NVIDIA Tegra PCIe controller >>> + >>> +Required properties: >>> +- compatible: "nvidia,tegra20-pcie" >>> +- reg: physical base address and length of the controller's registers >>> +- interrupts: the interrupt outputs of the controller >>> + >>> +Optional properties: >>> +- pex-clk-supply: supply voltage for internal reference clock >>> +- vdd-supply: power supply for controller (1.05V) >> >> Mark, Liam, >> >> Should those *-supply properties really be optional? I got the >> impression talking to Mark in a different thread that all regulators >> should exist, although their implementation may be via a fixed >> regulator, with no GPIO, as determined by the board design. > > If I read the TrimSlice code correctly, there is no regulator setup required > to make PCIe work there presumably because they hardwire the proper voltages. Yes. I believe that's exactly what the fixed regulator is for. > On the other hand, maybe a better solution in this case would be to use the > dummy regulator in those cases. Mark indicated dummy regulators weren't the preferred mechanism: http://lkml.org/lkml/2012/2/25/30