On Tue, 2020-01-07 at 11:20 +0100, Linus Walleij wrote: > On Mon, Dec 23, 2019 at 4:11 AM Hanks Chen <hanks.chen@xxxxxxxxxxxx> wrote: > > On Fri, 2019-08-23 at 10:57 +0200, Linus Walleij wrote: > > > On Mon, Aug 19, 2019 at 11:22 AM Mars Cheng <mars.cheng@xxxxxxxxxxxx> wrote: > > > > This does not explain what a "virtual GPIO" is in this > > > context, so please elaborate. What is this? Why does > > > it exist? What is it used for? > > > > > > GPIO is "general purpose input/output" and it is a > > > pretty rubbery category already as it is, so we need > > > to define our terms pretty strictly. > > > > > Virtual GPIO only used inside SOC and not being exported to outside SOC > > in MTK platform. Some modules use virtual GPIO as eint (e.g. pmic or > > usb). > > I would call that internal GPIOs, those are very real rails inside > the chip made with polysilicone so there is nothing "virtual" > about them. If the documentation for the chip calls them virtual > then explain in the driver that these are SoC-internal > lines so that everyone will get it. > Got it, I will add the info into the driver in v3 > Is the PMIC inside the SoC? I thought that was usually outside of it > in its own chip. > > But I suppose there could be some interface to it in the SoC and > then that interface has this EINT? > That's right. I use incorrect word. e.g. pmic interface inside the SOC (PMIF), not pmic... > > In MTK platform, external interrupt (EINT) and GPIO is 1-1 mapping and > > we can set GPIO as eint. > > But some modules use specific eint which doesn't have real GPIO pin. > > So we use virtual GPIO to map it. > > OK I get it I think... just put these comments into the code as well > so we understand when reading the code what is going on. Got it, will add the comments in v3. Thanks for reviewing. > > > > > + if (mtk_is_virt_gpio(hw, gpio)) > > > > + return 1; > > > > > > Why are "virtual GPIOs" always inputs? > > > > We set virtual GPIO as eint. > > It mean virtual GPIO only used inside SOC and not being exported to > > outside SOC. > > Are you saying that: > - "Virtual" GPIOs are always and only used for interrupts > - Since they are only used for interrupts, they are always inputs > > Then write that in a comment to the above change so we know > this context. > Yes, virtual GPIOs are always and only used for interrupts in mtk platform. I'll add the comments in v3. Thanks for reviewing > Yours, > Linus Walleij > > _______________________________________________ > Linux-mediatek mailing list > Linux-mediatek@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-mediatek
