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. > 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. -- With Best Regards, Andy Shevchenko
