linux-kernel - RE: [PATCH] regulator: Use bitfield values for range selectors

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Message-ID: <f5e6353f324343df8c289d8aed2a8930@AcuMS.aculab.com>
Date:   Mon, 12 Jun 2023 10:13:40 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Chen-Yu Tsai' <wenst@...omium.org>
CC:     Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Manivannan Sadhasivam <mani@...nel.org>,
        Cristian Ciocaltea <cristian.ciocaltea@...il.com>,
        Matti Vaittinen <mazziesaccount@...il.com>,
        "linux-actions@...ts.infradead.org" 
        <linux-actions@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: RE: [PATCH] regulator: Use bitfield values for range selectors

From: Chen-Yu Tsai
> Sent: 12 June 2023 10:27
> To: David Laight <David.Laight@...LAB.COM>
> Cc: Mark Brown <broonie@...nel.org>; Liam Girdwood <lgirdwood@...il.com>; Manivannan Sadhasivam
> <mani@...nel.org>; Cristian Ciocaltea <cristian.ciocaltea@...il.com>; Matti Vaittinen
> <mazziesaccount@...il.com>; linux-actions@...ts.infradead.org; linux-kernel@...r.kernel.org; linux-
> arm-kernel@...ts.infradead.org
> Subject: Re: [PATCH] regulator: Use bitfield values for range selectors
> 
> On Mon, Jun 12, 2023 at 3:48 PM David Laight <David.Laight@...lab.com> wrote:
> >
> > From: Chen-Yu Tsai
> > > Sent: 12 June 2023 04:39
> > >
> > > On Sun, Jun 11, 2023 at 1:10 AM David Laight <David.Laight@...lab.com> wrote:
> > > >
> > > > From: Chen-Yu Tsai
> > > > > Sent: 08 June 2023 08:57
> > > > >
> > > > > Right now the regulator helpers expect raw register values for the range
> > > > > selectors. This is different from the voltage selectors, which are
> > > > > normalized as bitfield values. This leads to a bit of confusion. Also,
> > > > > raw values are harder to copy from datasheets or match up with them,
> > > > > as datasheets will typically have bitfield values.
> > > > >
> > > > > Make the helpers expect bitfield values, and convert existing users.
> > > > > Include bitops.h explicitly for ffs(), and reorder the header include
> > > > > statements. While at it, also replace module.h with export.h, since the
> > > > > only use is EXPORT_SYMBOL_GPL.
> > > > >
> > > > ...
> > > > >  static const unsigned int atc260x_ldo_voltage_range_sel[] = {
> > > > > -     0x0, 0x20,
> > > > > +     0x0, 0x1,
> > > > >  };
> > > >
> > > > Is there any way the change can be done so that un-edited
> > > > modules fail to compile?
> > > > Otherwise the whole thing is an accident waiting to happen.
> > >
> > > I think we could change the field name in the regulator description?
> > > But unsuspecting end users / developers might just edit the name and not
> > > see that the scheme has changed.

Looking at it, that would seem to be needed.

	David

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