Re: [PATCH 2/7] [RFC] Common power driver for Linux gadgets

From: Russell King
Date: Mon Apr 16 2007 - 16:16:41 EST


On Fri, Apr 13, 2007 at 05:50:01PM +0400, Anton Vorontsov wrote:
> +/*
> + * include/linux/ioport.h does not provide flags for generic IRQ trigger
> + * types. So, we're using "ISA PnP IRQ specific bits", and converting them.
> + */
> +static unsigned int get_irq_flags(struct resource *res)
> +{
> + unsigned int flags = IRQF_DISABLED;
> +
> + if (res->flags & IORESOURCE_IRQ_HIGHEDGE)
> + flags |= IRQF_TRIGGER_RISING;
> + if (res->flags & IORESOURCE_IRQ_LOWEDGE)
> + flags |= IRQF_TRIGGER_FALLING;
> + if (res->flags & IORESOURCE_IRQ_HIGHLEVEL)
> + flags |= IRQF_TRIGGER_HIGH;
> + if (res->flags & IORESOURCE_IRQ_LOWLEVEL)
> + flags |= IRQF_TRIGGER_LOW;
> + if (res->flags & IORESOURCE_IRQ_SHAREABLE)
> + flags |= IRQF_SHARED;
> +
> + return flags;
> +}

Eww. The IORESOURCE IRQ bits are intentionally chosen to be the same as
the IRQF bits:

include/linux/interrupt.h:
/*
* These correspond to the IORESOURCE_IRQ_* defines in
* linux/ioport.h to select the interrupt line behaviour. When
* requesting an interrupt without specifying a IRQF_TRIGGER, the
* setting should be assumed to be "as already configured", which
* may be as per machine or firmware initialisation.
*/

The exception is IRQF_SHARED which should be a _driver_ choice not a
_platform_ choice, and therefore makes no sense in your "get_irq_flags"
definition.

Plus, if we ever did want to introduce such a function, it should be
a generic thing, not specific to some random power subsystem de jour.

--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of:
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