> -----Original Message----- > From: Andrew Lunn <andrew@xxxxxxx> > Sent: Thursday, May 18, 2023 8:49 PM > To: Jiawen Wu <jiawenwu@xxxxxxxxxxxxxx> > Cc: 'Andy Shevchenko' <andy.shevchenko@xxxxxxxxx>; netdev@xxxxxxxxxxxxxxx; jarkko.nikula@xxxxxxxxxxxxxxx; > andriy.shevchenko@xxxxxxxxxxxxxxx; mika.westerberg@xxxxxxxxxxxxxxx; jsd@xxxxxxxxxxxx; Jose.Abreu@xxxxxxxxxxxx; > hkallweit1@xxxxxxxxx; linux@xxxxxxxxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx; linux-gpio@xxxxxxxxxxxxxxx; mengyuanlou@xxxxxxxxxxxxx > Subject: Re: [PATCH net-next v8 6/9] net: txgbe: Support GPIO to SFP socket > > > > 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. > > > > 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? > > That is your upstream IRQ, the interrupt indicating one of your GPIO > lines has changed state. > > > 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. > > Do you have one MSI-X dedicated for GPIOs. Or is it your general MAC > interrupt, and you need to read an interrupt controller register to > determine it was GPIOs which triggered the interrupt? I have one MSI-X interrupt for all general MAC interrupt (see TXGBE_PX_MISC_IEN_MASK). It has 32 bits to indicate various interrupts, GPIOs are the one of them. When GPIO interrupt is determined, GPIO_INT_STATUS register should be read to determine which GPIO line has changed state. > If you are getting errors when removing the driver it means you are > missing some level of undoing what us done in probe. Are you sure > regmap_del_irq_chip() is being called on unload? I used devm_* all when I registered them. > > 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... > > That is probably some sort of naming issue. You might want to add some > prints in swnode_find_gpio() and gpiochip_find() to see what it is > looking for vs what the name actually is. Thanks for the advice, I'll try again today.
