Hi, I'm currently (and for the next three weeks) on vacation. Sorry in advanced if the format of the mail is wrong or similar. I just have access to my mobile. Am 18. Mai 2023 14:27:00 MESZ schrieb Andy Shevchenko <andy.shevchenko@xxxxxxxxx>: >On Thu, May 18, 2023 at 2:50 PM Jiawen Wu <jiawenwu@xxxxxxxxxxxxxx> wrote: >> On Wednesday, May 17, 2023 11:01 PM, Andrew Lunn wrote: >> > On Wed, May 17, 2023 at 10:55:01AM +0800, Jiawen Wu wrote: > >... > >> > > I should provide gpio_regmap_config.irq_domain if I want to add the gpio_irq_chip. >> > > But in this use, GPIO IRQs are requested by SFP driver. How can I get irq_domain >> > > before SFP probe? And where do I add IRQ parent handler? >> > >> > I _think_ you are mixing upstream IRQs and downstream IRQs. >> > >> > Interrupts are arranged in trees. The CPU itself only has one or two >> > interrupts. e.g. for ARM you have FIQ and IRQ. When the CPU gets an >> > interrupt, you look in the interrupt controller to see what external >> > or internal interrupt triggered the CPU interrupt. And that interrupt >> > controller might indicate the interrupt came from another interrupt >> > controller. Hence the tree structure. And each node in the tree is >> > considered an interrupt domain. >> > >> > A GPIO controller can also be an interrupt controller. It has an >> > upstream interrupt, going to the controller above it. And it has >> > downstream interrupts, the GPIO lines coming into it which can cause >> > an interrupt. And the GPIO interrupt controller is a domain. >> > >> > So what exactly does gpio_regmap_config.irq_domain mean? Is it the >> > domain of the upstream interrupt controller? Is it an empty domain >> > structure to be used by the GPIO interrupt controller? It is very >> > unlikely to have anything to do with the SFP devices below it. >> >> Sorry, since I don't know much about interrupt, it is difficult to understand >> regmap-irq in a short time. There are many questions about regmap-irq. > >That's why I Cc'ed to Michael who is the author of gpio-regmap to >probably get advice from. All gpio remap is doing is forwarding the IRQ domain from regmap-irq to the gpio subsystem. It's opaque to gpio-regmap and outside the scope of gpio-regmap. -michael >> When I want to add an IRQ chip for regmap, for the further irq_domain, >> I need to pass a parameter of IRQ, and this IRQ will be requested with handler: >> regmap_irq_thread(). Which IRQ does it mean? In the previous code of using >> devm_gpiochip_add_data(), I set the MSI-X interrupt as gpio-irq's parent, but >> it was used to set chained handler only. Should the parent be this IRQ? I found >> the error with irq_free_descs and irq_domain_remove when I remove txgbe.ko. >> >> As you said, the interrupt of each tree node has its domain. Can I understand >> that there are two layer in the interrupt tree for MSI-X and GPIOs, and requesting >> them separately is not conflicting? Although I thought so, but after I implement >> gpio-regmap, SFP driver even could not find gpio_desc. Maybe I missed something >> on registering gpio-regmap... >> >> Anyway it is a bit complicated, could I use this version of GPIO implementation if >> it's really tough? > >It's possible but from GPIO subsystem point of view it's discouraged >as long as there is no technical impediment to go the regmap way.
