Re: [PATCH 2/3] hwmon: (lm90) add support to handle irq

From: Guenter Roeck <linux-0h96xk9xTtrk1uMJSBkQmQ@public.gmane.org>
To: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
Cc: Wei Ni <wni-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>,
	khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org,
	acourbot-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org,
	MLongnecker-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org,
	lm-sensors-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org,
	linux-kernel-u79uwXL29TZX6JHB/w77yyCwEArCW2h5@public.gmane.org,
	linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 2/3] hwmon: (lm90) add support to handle irq
Date: Mon, 8 Jul 2013 13:06:23 -0700	[thread overview]
Message-ID: <20130708200623.GA1506@roeck-us.net> (raw)
In-Reply-To: <51DADEE1.1030408-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>

On Mon, Jul 08, 2013 at 09:46:41AM -0600, Stephen Warren wrote:
> On 07/05/2013 01:47 PM, Guenter Roeck wrote:
> > On Fri, Jul 05, 2013 at 11:35:05AM -0600, Stephen Warren wrote:
> >> On 07/04/2013 01:57 AM, Wei Ni wrote:
> >>> Add support to handle irq. When the temperature touch
> >>> the limit value, the driver can handle the interrupt.
> >>
> >>> +	if (client->irq >= 0) {
> >>
> >> 0 isn't a valid IRQ, so you can write that as simply if (client->irq).
> >>
> > If I recall correctly, it is valid on some platforms.
> 
> I thought ARM (just some ARM sub-architectures?) might have been the
> last architecture, and even irrespective of that, we were trying not to
> introduce any new code that relies on this strangeness, so it doesn't
> propagate?
> 
Sounds good to me. Another problem, though, may be that NO_IRQ is sometimes
defined as -1, sometimes as 0, sometimes as 0xffffffff, and sometimes as INT_MAX.
Which of course is another mess :(.

Guenter