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Date:   Tue, 11 Apr 2023 10:05:25 -0400
From:   William Breathitt Gray <william.gray@linaro.org>
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
        Johannes Berg <johannes.berg@intel.com>,
        Jonathan Cameron <jic23@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>
Subject: Re: [PATCH v3 3/3] counter: 104-quad-8: Utilize helper functions to
 handle PR, FLAG and PSC
Message-ID: <ZDVpJb9DyIU+5eJf@fedora>
References: <cover.1681134558.git.william.gray@linaro.org>
 <669c8f782f11fe27c4568e4fc3ba459c4f954874.1681134558.git.william.gray@linaro.org>
 <ZDVli05x7u/bg7Zc@smile.fi.intel.com>
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On Tue, Apr 11, 2023 at 04:50:03PM +0300, Andy Shevchenko wrote:
> On Mon, Apr 10, 2023 at 10:03:13AM -0400, William Breathitt Gray wrote:
> > The Preset Register (PR), Flag Register (FLAG), and Filter Clock
> > Prescaler (PSC) have common usage patterns. Wrap up such usage into
> > dedicated functions to improve code clarity.
>=20
> ...
>=20
> >  	*val =3D 0;
>=20
> Is not needed now as always being initialized by below call.

The regmap_noinc_read() call only reads the number of bytes requested.
Since we request 3 bytes, the upper bytes of the u64 val remain
uninitialized, so that is why we need to set *val =3D 0. This isn't
immediately clear in the code, so I can add a comment to make it
explicit.

>=20
> >  	spin_lock_irqsave(&priv->lock, irqflags);
> > =20
> >  	iowrite8(SELECT_RLD | RESET_BP | TRANSFER_CNTR_TO_OL, &chan->control);
> > -
> > -	for (i =3D 0; i < 3; i++)
> > -		*val |=3D (unsigned long)ioread8(&chan->data) << (8 * i);
> > +	ioread8_rep(&chan->data, val, 3);
> > =20
> >  	spin_unlock_irqrestore(&priv->lock, irqflags);
>=20
> ...
>=20
> > +	struct channel_reg __iomem *const chan =3D priv->reg->channel + id;
>=20
> Not sure if array representation will look better here and elsewhere.
>=20
> 	struct channel_reg __iomem *const chan =3D &priv->reg->channel[id];

Perhaps so, but all these struct channel_reg lines will go away in the
next patch [0] migrating to the regmap API, so for the sake of stability
of this patch I hesitate to change these lines.

William Breathitt Gray

[0] https://lore.kernel.org/all/20230410141252.143998-1-william.gray@linaro=
=2Eorg/

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