Re: [PATCH v3 1/2] gpio: mlxbf2: Introduce IRQ support
From: Andrew Lunn <andrew@lunn.ch>
Date: 2021-09-27 19:10:53
Also in:
linux-acpi, linux-gpio, lkml
From: Andrew Lunn <andrew@lunn.ch>
Date: 2021-09-27 19:10:53
Also in:
linux-acpi, linux-gpio, lkml
Asmaa>> Thank you very much for the detailed and clear explanation! we only enable/support link up/down interrupts. QA has tested bringing up/down the network interface +200 times in a loop.
The micrel driver currently only uses two interrupts of the available 8. So it will be hard to trigger the problem with the current driver. Your best way to trigger it is going to bring the link down as soon as it goes up. So you get first a link up, and then a link down very shortly afterwards. There is however nothing stopping developers making use of the other interrupts. That will then increase the likelihood of problems. What does help you is that the interrupt register is clear on read. So the race condition window is small.
The software interrupt and handler is not registered
based on the GPIO interrupt but rather a HW interrupt which is
common to all GPIO pins (irrelevant here, but this is edge triggered):
ret = devm_request_irq(dev, irq, mlxbf2_gpio_irq_handler,
IRQF_SHARED, name, gs);
IRQF_SHARED implied level. You cannot have a shared interrupt which is
using edges.
Andrew