linux-kernel - Re: [PATCH 1/4] mfd: mc13783: Take care of semantic inversion between read and write value of two bits in POWER

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Date:	Tue, 5 Jan 2010 20:55:20 +0100
From:	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
To:	Samuel Ortiz <sameo@...ux.intel.com>
Cc:	Alberto Panizzo <maramaopercheseimorto@...il.com>,
	Sergei Shtylyov <sshtylyov@...mvista.com>,
	Sascha linux-arm <s.hauer@...gutronix.de>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	linux-arm-kernel-infradead <linux-arm-kernel@...ts.infradead.org>,
	Liam Girdwood <lrg@...mlogic.co.uk>
Subject: Re: [PATCH 1/4] mfd: mc13783: Take care of semantic inversion
	between read and write value of two bits in POWER_MISCELLANEUS
	register.

On Tue, Jan 05, 2010 at 07:15:42PM +0100, Samuel Ortiz wrote:
> > @@ -187,6 +190,13 @@ int mc13783_reg_write(struct mc13783 *mc13783, unsigned int offset, u32 val)
> >  
> >         buf = 1 << 31 | offset << MC13783_REGOFFSET_SHIFT | val;
> >  
> > +       /* Take care of table 4-24 in Freescale MC13783IGPLDRM.pdf making
> > +        * the assumption that PWGTnDRV signals controls core power supplies
> > +        * that software must not disable. */
> > +       if (offset == MC13783_REG_POWER_MISCELLANEOUS)
> > +               buf &= ~(MC13783_REGCTRL_PWGT1SPIEN |
> > +                        MC13783_REGCTRL_PWGT2SPIEN);
> > +
> Although I see where you want to go, I dont really enjoy that solution.
> I would prefere to have specific register write/rmw routines for
> MC13783_REG_POWER_MISCELLANEOUS, and at the same time forbid to access the
> latter from the current mc13783_reg_* API.
Ack.  This is what I already suggested in

	http://thread.gmane.org/gmane.linux.kernel/927112/focus=930317

(This happend to be a reply to patch 2/4 as I replied to Alberto's ping
for patches 1 and 2.)

Best regards
Uwe

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