linux-kernel - Re: [PATCH v3] i2c: imx: make bus recovery through pinctrl optional

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Message-ID: <20160115090343.GK24441@pengutronix.de>
Date:	Fri, 15 Jan 2016 10:03:43 +0100
From:	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
To:	Li Yang <leoli@...escale.com>
Cc:	Li Yang <leoyang.li@....com>, Gao Pan <pandy.gao@....com>,
	Wolfram Sang <wsa@...-dreams.de>,
	Linus Walleij <linus.walleij@...aro.org>,
	lkml <linux-kernel@...r.kernel.org>, linux-gpio@...r.kernel.org,
	"linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v3] i2c: imx: make bus recovery through pinctrl optional

Hello Li,

On Fri, Jan 15, 2016 at 04:46:06PM +0800, Li Yang wrote:
> On Fri, Jan 15, 2016 at 3:53 PM, Uwe Kleine-König
> <u.kleine-koenig@...gutronix.de> wrote:
> >> -     i2c_imx_init_recovery_info(i2c_imx, pdev);
> >> +     if (IS_ERR_OR_NULL(i2c_imx->pinctrl))
> >
> > I'd prefer to set i2c_imx->pinctrl to NULL if it's not used and then use
> >
> >         if (!i2c_imx->pinctrl)
> >
> > here. (Or maybe make i2c_imx_init_recovery_info aware of this situation
> > to keep the caller simple?)
> 
> Setting not used pointer to NULL might be a good coding practice
> generally.  But in this case neither the driver nor gpio framework
> checks if the pinctrl is NULL before accessing it.  We still need the
> driver to make sure pinctrl is not used in this situation.  The
> benefit of the proposed change seems to be pretty limited.  :)

At least it gets rid of IS_ERR_OR_NULL which is used wrongly more often
than not.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |