> -----Original Message----- > From: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx> > Sent: 2022年3月4日 15:46 > To: Hongxing Zhu <hongxing.zhu@xxxxxxx> > Cc: Francesco Dolcini <francesco.dolcini@xxxxxxxxxxx>; > l.stach@xxxxxxxxxxxxxx; bhelgaas@xxxxxxxxxx; broonie@xxxxxxxxxx; > lorenzo.pieralisi@xxxxxxx; jingoohan1@xxxxxxxxx; festevam@xxxxxxxxx; > linux-pci@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; dl-linux-imx > <linux-imx@xxxxxxx> > Subject: Re: [PATCH v8 5/8] PCI: imx6: Refine the regulator usage > > On Mon, Feb 28, 2022 at 03:43:03AM +0000, Hongxing Zhu wrote: > > > 2. We are playing around with vpcie during regulator during > > > suspend/resume, why? We currently have issue with suspend/resume > > > when a PCIe switch is there, with the final effect of PCIe being not > > > usable afterward. I fear like this is related to our issue. > > > > > To my understands, the VPCIE is the abstract of the DIESABLE# signal. > > Refer to the Chapter 3.1.12.3 W_DISABLE# Signal of PCI Express M.2 SPEC. > > These signals are used to disable the Adapter's radio operation to > > meet public Safety regulations or when otherwise desired. > > It's reasonable to assert/de-assert W_DISABLE# signal during > suspend/resume. > > > > > What about vpcie enable in probe, and vpcie disable in shutdown and > > > that's all? > > The W_DISABLE# Signal is used to control the radios on the Adapters. > > I think you can do that, if the radios are always on in your system. > > According to the binding documentation (imx6q-pcie.yaml) > > vpcie-supply: > description: Should specify the regulator in charge of PCIe port power. > The regulator will be enabled when initializing the PCIe host and > disabled either as part of the init process or when shutting down > the host (optional required). > > This is how it's documented to be used, if this is used according to the > documentation (and this is happening) what you are already doing (not > changed in this patch, you are right) is not correct. > > Abusing this for the W_DISABLE# disable is new to me and does not look legit. The vpcie-supply is one gpio regulator actually, used to control remote Endpoint device, through the DISABLE# signal (defined in Mini CEM/M.2 SPEC) of the port. Best Regards Richard Zhu > > Francesco
