Messages in this thread | | | Subject | Re: [PATCH v5 2/3] gpio: loongson: add gpio driver support | From | Yinbo Zhu <> | Date | Tue, 20 Dec 2022 11:27:00 +0800 |
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在 2022/12/13 下午5:36, Linus Walleij 写道: > On Mon, Dec 12, 2022 at 9:13 AM Yinbo Zhu <zhuyinbo@loongson.cn> wrote: > >> mask_irq/unmask_irq/irq_ack/ function always be called by >> handle_level_irq/handle_edge_irq in current irq domain. and the >> handle_level_irq/handle_edge_irq will be called by handle_irq_desc that >> ask know which irq is. >> >> when a peripheral need to use a gpio irq that gpio irq driver need know >> irq status and call irq desc->irq_handler. >> >> so I don't got it about which case it is unnecessary to know which irq. > > Sorry I don't understand what you are asking, can you elaborate? > > Do you mean that you don't know which driver will not call ->to_irq() > on the gpiochip? That would be any driver that takes an IRQ directly in > the device tree: > > gpio: gpio { > interrupt-controller; > #interrupt-cells = <2>; > .... > }; > > device { > interrupts = <&gpio 14 IRQ_TYPE_LEVEL_HIGH>; > .... > }; > > This case will only call the irqchip callbacks and will never call > the .to_irq() on the gpio_chip.
I mean that if the current domain is a valid doamin, every interrupt must have an interrupt status.
If there is no interrupt status, no one can cover the interrupt, and no one will call 14 irq's desc->handle_irq (handle_level_irq) and Loongson-2 gpio doesn't have irq status register, so Loongson-2 gpio irqchip shouldn't be implemented. > >>> You find an example of a hierarchical GPIO irqchip using the >>> GPIOLIB_IRQCHIP in drivers/gpio/gpio-ixp4xx.c. >> >> Loongson-2 gpio irq hardware only a enable register, and when a gpio irq >> happen, then will has a such flow: "cpuintc -> liointc -> gpioinc -> >> generic_handle_domain_irq -> handle_level_irq -> >> peripheral-action(action->handler)" >> >> generic_handle_domain_irq need rely on specific hwirq that ask gpio irq >> hardware has a status register but Loongson-2 gpio irq hardware doesn't >> have it. >> >> so I still think it wasn't appropriate that for loongson-2 gpio driver >> add a irq chip. > > generic_handle_domain_irq() is of no concern, what matters is if > your interrupt is hierarchical or not, the callback in the GPIO chip > can be a simple remapping of the numberspace followed by > a call to the parent callbacks. > > Yours, > Linus Walleij Hi
I think gpio irq domain should be a normal irq domain that like other irq domain. that need a function A to call virq desc handler in gpio irq domain. if no use generic_handler_domain_irq or similar interface, that will no one to call irq_desc->irq_handler.
"cpuintc -> liointc -> gpioinc -> generic_handle_domain_irq -> handle_level_irq -> peripheral-action(action->handler)" >
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