From: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
To: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: megous@megous.com, mark.rutland@arm.com, arnd@arndb.de,
devicetree@vger.kernel.org, gregkh@linuxfoundation.org,
linux-kernel@vger.kernel.org,
Rikard Falkeborn <rikard.falkeborn@gmail.com>,
kishon@ti.com, linux-sunxi@googlegroups.com, robh+dt@kernel.org,
mripard@kernel.org, tglx@linutronix.de, wens@csie.org,
linux-arm-kernel@lists.infradead.org, icenowy@aosc.io
Subject: Re: [PATCH] phy: allwinner: Fix GENMASK misuse
Date: Fri, 8 Nov 2019 09:29:07 +0100 [thread overview]
Message-ID: <20191108082907.GA848664@aptenodytes> (raw)
In-Reply-To: <20191107233914.GW25745@shell.armlinux.org.uk>
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Hi,
On Thu 07 Nov 19, 23:39, Russell King - ARM Linux admin wrote:
> On Thu, Nov 07, 2019 at 09:46:45PM +0100, Rikard Falkeborn wrote:
> > Arguments are supposed to be ordered high then low.
> >
> > Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
> > ---
> > Spotted while trying to add compile time checks of GENMASK arguments.
> > Patch has only been compile tested.
>
> My feeling, personally, is that GENMASK() really isn't worth the pain
> it causes. Can we instead get rid of this thing and just use easier
> to understand and less error-prone hex masks please?
One advantage it has is that is matches the order in which bit fields are
usually given in datasheets, so I personally found that it makes verification
of fields much more straightforward and immediate.
My 2 cents are that it makes sense for hardware registers.
Note that I have recently introduced a SHIFT_AND_MASK_BITS macro[0] for a V4L2
driver, that I (and Mauro) would like to move to linux/bits.h eventually.
> I don't care what anyone else says, personally I'm going to stick with
> using hex masks as I find them way easier to get right first time than
> a problematical opaque macro - and I really don't want the effort of
> finding out that I've got the arguments wrong when I build it. It's
> just _way_ easier and less error prone to use a hex mask straight off.
I guess it's a matter of personal habit.
[0]: https://git.linuxtv.org/media_tree.git/commit/?id=06eff2150d4db991ca236f3d05a9dc0101475aea
Cheers,
Paul
--
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com
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next prev parent reply other threads:[~2019-11-08 8:29 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-20 13:42 [PATCH 0/4] Add USB 3 support for H6 and Orange Pi 3 megous
2019-10-20 13:42 ` [PATCH 1/4] dt-bindings: Add bindings for USB3 phy on Allwinner H6 megous
2019-10-21 11:06 ` Maxime Ripard
2019-10-20 13:42 ` [PATCH 2/4] phy: allwinner: add phy driver for USB3 PHY on Allwinner H6 SoC megous
2019-10-21 11:08 ` Maxime Ripard
2019-11-07 20:46 ` [PATCH] phy: allwinner: Fix GENMASK misuse Rikard Falkeborn
2019-11-07 21:45 ` Ondřej Jirman
2019-11-08 11:29 ` Icenowy Zheng
2019-11-08 11:41 ` Ondřej Jirman
2019-11-08 11:43 ` Ondřej Jirman
2019-11-07 23:39 ` Russell King - ARM Linux admin
2019-11-08 1:46 ` Joe Perches
2019-11-08 8:29 ` Paul Kocialkowski [this message]
2019-11-10 12:43 ` [PATCH v2] " Rikard Falkeborn
2019-11-24 22:10 ` Rikard Falkeborn
2019-12-09 20:18 ` Rikard Falkeborn
2020-02-22 23:41 ` [PATCH v2 RESEND] " Ondrej Jirman
2020-02-23 3:23 ` [linux-sunxi] " Chen-Yu Tsai
2020-02-24 9:18 ` Maxime Ripard
2019-10-20 13:42 ` [PATCH 3/4] arm64: dts: allwinner: h6: add USB3 device nodes megous
2019-10-20 13:42 ` [PATCH 4/4] arm64: dts: allwinner: orange-pi-3: Enable USB 3.0 host support megous
2019-10-21 11:09 ` Maxime Ripard
2019-11-04 12:16 ` Ondřej Jirman
2019-11-05 10:45 ` Maxime Ripard
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