From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?=
	<u.kleine-koenig@pengutronix.de>
Subject: Re: [PATCH 3/3] hwrng: mxc-fsl - add support for Freescale RNGC
Date: Tue, 1 Mar 2016 08:49:37 +0100
Message-ID: <20160301074937.GU2613@pengutronix.de>
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Cc: Steffen Trumtrar <s.trumtrar@pengutronix.de>,
	Mark Rutland <mark.rutland@arm.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Pawel Moll <pawel.moll@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Kumar Gala <galak@codeaurora.org>,
	Rob Herring <robh+dt@kernel.org>, linux-crypto@vger.kernel.org,
	Sascha Hauer <kernel@pengutronix.de>,
	Matt Mackall <mpm@selenic.com>,
	Shawn Guo <shawnguo@kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>
To: Fabio Estevam <festevam@gmail.com>
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In-Reply-To: <CAOMZO5BLYumOrBuoB5-RgzLAJ=o4zp9ocv4jcZRy=p6Pky1SyQ@mail.gmail.com>
Sender: linux-crypto-owner@vger.kernel.org

Hello Fabio,

On Mon, Feb 29, 2016 at 08:54:19PM -0300, Fabio Estevam wrote:
> On Mon, Feb 29, 2016 at 6:38 PM, Uwe Kleine-K=F6nig
> <u.kleine-koenig@pengutronix.de> wrote:
> > On Mon, Feb 29, 2016 at 06:16:50PM -0300, Fabio Estevam wrote:
> >> On Mon, Feb 29, 2016 at 12:52 PM, Steffen Trumtrar
> >> <s.trumtrar@pengutronix.de> wrote:
> >>
> >> > +       ret =3D clk_prepare_enable(rngc->clk);
> >> > +       if (ret)
> >> > +               return ret;
> >> > +
> >> > +       rngc->irq =3D platform_get_irq(pdev, 0);
> >> > +       if (!rngc->irq) {
> >> > +               dev_err(&pdev->dev, "FSL RNGC couldn't get irq\n=
");
> >> > +               clk_disable_unprepare(rngc->clk);
> >> > +
> >> > +               return ret;
> >>
> >> You are returning the wrong error code here:
> >>
> >> Better do like this:
> >>
> >>        rngc->irq =3D platform_get_irq(pdev, 0);
> >>        if (rngc->irq < 0) {
> >
> > rngc->irq is unsigned, so this is never true.
> >
> >>                dev_err(&pdev->dev, "FSL RNGC couldn't get irq\n");
> >>                clk_disable_unprepare(rngc->clk);
> >>                return rngc->irq;
> >>        }
> >
> > So here comes my better approach:
>=20
> As irq is only used inside probe it can be removed from struct mxc_rn=
gc.

Good idea.

> Or maybe like this:
>=20
>          ret =3D platform_get_irq(pdev, 0);
>          if (ret < 0) {
>                  dev_err(&pdev->dev, "FSL RNGC couldn't get irq\n");
>                  clk_disable_unprepare(rngc->clk);
>                  return ret;
>          }

Some people think platform_get_irq returning 0 should be handled as
error.

Best regards
Uwe

--=20
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