linux-kernel - Re: [PATCH v3 2/3] i2c: designware: detect when dynamic tar update is possible

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Message-ID: <1471438125.2406.6.camel@intel.com>
Date:	Wed, 17 Aug 2016 12:48:56 +0000
From:	"De Marchi, Lucas" <lucas.demarchi@...el.com>
To:	"jarkko.nikula@...ux.intel.com" <jarkko.nikula@...ux.intel.com>,
	"linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>
CC:	"mika.westerberg@...ux.intel.com" <mika.westerberg@...ux.intel.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"christian.ruppert@...tech.com" <christian.ruppert@...tech.com>,
	"Souza, Jose" <jose.souza@...el.com>
Subject: Re: [PATCH v3 2/3] i2c: designware: detect when dynamic tar update
 is possible

On Wed, 2016-08-17 at 11:05 +0300, Jarkko Nikula wrote:
> On 08/16/2016 05:07 PM, De Marchi, Lucas wrote:
> > 
> > On Tue, 2016-08-16 at 17:00 +0300, Jarkko Nikula wrote:
> > > 
> > > > 
> > > > +	 */
> > > > +	reg = dw_readl(dev, DW_IC_CON);
> > > > +	dw_writel(dev, reg ^ DW_IC_CON_10BITADDR_MASTER,
> > > > DW_IC_CON);
> > > > +
> > > > +	if ((dw_readl(dev, DW_IC_CON) &
> > > > DW_IC_CON_10BITADDR_MASTER) ==
> > > > +	    (reg & DW_IC_CON_10BITADDR_MASTER)) {
> > > > +		dev->dynamic_tar_update_enabled = true;
> > > > +		dev_dbg(dev->dev, "Dynamic TAR update
> > > > enabled");
> > > > +	}
> > > 
> > > Is this possible to move to i2c_dw_probe()? I guess the enabled
> > > status
> > > doesn't change runtime?
> > 
> > It was actually useful at this place during development of this
> > patch
> > because we could check any unexpected change in behavior when
> > resuming.
> > We did catch a bug because of this and fixed.
> > I'm not sure if now it makes more sense to move to probe method.
> > I'd
> > leave it where it is, but I'm open to move it there.
> > 
> Can you do a quick re-test that case to see does it change runtime?
> If 
> it does then this needs a comment why there is need to do this check 
> each time when HW is reinitialized. Otherwise there is chance
> someone 
> may move this code to probe time in the future.

I already tested and it doesn't change. I'll move it to i2c_dw_probe()
then.

thanks

Lucas De Marchi