linux-kernel - RE: [PATCH v2 1/4] MFD: Palmas: Check if interrupts property exists and then only request irq

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Message-ID: <DC88CAD03C0052499C1907B327FC63229EC563@DBDE04.ent.ti.com>
Date:	Tue, 18 Jun 2013 16:54:28 +0000
From:	"J, KEERTHY" <j-keerthy@...com>
To:	Stephen Warren <swarren@...dotorg.org>
CC:	"linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
	"broonie@...nel.org" <broonie@...nel.org>,
	"ldewangan@...dia.com" <ldewangan@...dia.com>,
	"sameo@...ux.intel.com" <sameo@...ux.intel.com>,
	"grant.likely@...retlab.ca" <grant.likely@...retlab.ca>,
	"swarren@...dia.com" <swarren@...dia.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
	"gg@...mlogic.co.uk" <gg@...mlogic.co.uk>
Subject: RE: [PATCH v2 1/4] MFD: Palmas: Check if interrupts property exists
 and then only request irq

Hi Stephen,

> -----Original Message-----
> From: Stephen Warren [mailto:swarren@...dotorg.org]
> Sent: Tuesday, June 18, 2013 9:22 PM
> To: J, KEERTHY
> Cc: linux-omap@...r.kernel.org; broonie@...nel.org;
> ldewangan@...dia.com; sameo@...ux.intel.com; grant.likely@...retlab.ca;
> swarren@...dia.com; linux-kernel@...r.kernel.org; linux-
> doc@...r.kernel.org; gg@...mlogic.co.uk
> Subject: Re: [PATCH v2 1/4] MFD: Palmas: Check if interrupts property
> exists and then only request irq
> 
> On 06/18/2013 04:01 AM, J Keerthy wrote:
> > Check if interrupts property exists and then only request irq.
> > On some boards INT line might not be connected to a valid irq line on
> > the application processor. Hence keeping a check before requesting
> > irq.
> 
> When there is no interrupts property, surely i2c->irq == 0, which is an
> invalid IRQ, and hence there's no need to check this before copying the
> value?

The intent here is NOT to request irq with 0 or Invalid IRQ. The board
File will not populate the interrupts entry if the INT line is not
Connected. Hence the patch checks for the 'interrupts' property.

This is essential since I do not want the probe to return error
Just because the i2c->irq == 0. The explicit check for the property
Ensures that the board does not have the INT line connected to
A valid interrupt line on the other side.

> 
> In other words, I think this whole patch could just be:
> 
> + 	palmas->irq = i2c->irq;
> 
> right?

Just this will cause a probe failure. That is not what is needed.
Instead the probe should continue skipping irq part.

Regards,
Keerthy
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