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

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Date:	Mon, 16 Apr 2007 21:16:15 +0100
From:	Russell King <rmk+lkml@....linux.org.uk>
To:	Anton Vorontsov <cbou@...l.ru>
Cc:	linux-kernel@...r.kernel.org, kernel-discuss@...dhelds.org
Subject: Re: [PATCH 2/7] [RFC] Common power driver for Linux gadgets

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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