Dear Bjorn, Sorry for the late response and thanks for your comment. On Wed, 2023-01-11 at 16:14 -0600, Bjorn Helgaas wrote: > Hi, > > On Wed, Jan 11, 2023 at 11:25:41AM +0800, Jian Yang wrote: > > From: "jian.yang" <jian.yang@xxxxxxxxxxxx> > > > > 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. Yes. This delay was defined for a downstream device (e.g., a PCIe EP) which need an extra reset pin, not for Mediatek's PCIe controller itself. I suppose we need to add a property in devicetree to let user determine the delay time due to differences in requirements between various devices. Best regards, Jian Yang
