Re: [PATCH 02/19] gpio: altera: make use of raw_spinlock variants
From: Linus Walleij
Date: Wed Mar 15 2017 - 05:53:34 EST
On Thu, Mar 9, 2017 at 5:21 PM, Julia Cartwright <julia@xxxxxx> wrote:
> The altera gpio driver currently implements an irq_chip for handling
> interrupts; due to how irq_chip handling is done, it's necessary for the
> irq_chip methods to be invoked from hardirq context, even on a a real-time
> kernel. Because the spinlock_t type becomes a "sleeping" spinlock w/ RT
> kernels, it is not suitable to be used with irq_chips.
> A quick audit of the operations under the lock reveal that they do only
> minimal, bounded work, and are therefore safe to do under a raw spinlock.
> Signed-off-by: Julia Cartwright <julia@xxxxxx>