From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Lars-Peter Clausen <lars@metafoo.de>
Cc: Mark Brown <broonie@kernel.org>,
Manuel Lauss <manuel.lauss@gmail.com>,
alsa-devel <alsa-devel@alsa-project.org>,
Richard Purdie <richard@openedhand.com>,
patches@opensource.wolfsonmicro.com,
LKML <linux-kernel@vger.kernel.org>,
linux-sound@vger.kernel.org,
Manuel Lauss <manuel.lauss@googlemail.com>,
Bo Shen <voice.shen@atmel.com>,
linux-arm-kernel@lists.infradead.org,
Liam Girdwood <lrg@slimlogic.co.uk>
Subject: Re: [alsa-devel] [RFC PATCH] ASoC: wm8731: let codec to manage clock by itself
Date: Tue, 3 Feb 2015 17:17:33 +0000 [thread overview]
Message-ID: <20150203171733.GY8656@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <54D0FD1C.9020305@metafoo.de>
On Tue, Feb 03, 2015 at 05:53:48PM +0100, Lars-Peter Clausen wrote:
> On 02/03/2015 01:44 PM, Mark Brown wrote:
> >On Tue, Feb 03, 2015 at 08:54:57AM +0100, Manuel Lauss wrote:
> >
> >>+ wm8731->mclk = devm_clk_get(&spi->dev, "mclk");
> >>+ if (IS_ERR(wm8731->mclk)) {
> >>+ wm8731->mclk = NULL;
> >>+ dev_warn(&spi->dev, "assuming static MCLK\n");
> >>+ }
> >
> >This is broken for both deferred probe and in the case where the clock
> >API genuinely returns a NULL clock. Other than that it's the kind of
> >thing that we've done for some other drivers, though it's not good to
> >have to do this. Check them for correct behaviour.
>
> Ideally we'd introduce a {devm_}clk_get_optional(), with the same semantics
> as gpiod_get_optional(), which handles the finer details of differentiating
> between clock specified, but not yet probed, clock specified, but
> incorrectly and no clock specified, so this doesn't have to be done over and
> over by each driver.
No, we don't need to. It clk_get() already knows this distinction, and
it appropriately returns -ENOENT vs -EPROBE_DEFER according to whether
there's a clock specified in DT or not.
--
FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2015-02-03 17:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-03 3:33 [RFC PATCH] ASoC: wm8731: let codec to manage clock by itself Bo Shen
2015-02-03 7:54 ` Manuel Lauss
2015-02-03 12:44 ` Mark Brown
2015-02-03 14:40 ` Manuel Lauss
2015-02-03 16:21 ` Mark Brown
2015-02-04 3:45 ` Bo Shen
2015-02-04 11:13 ` Mark Brown
2015-02-03 16:53 ` [alsa-devel] " Lars-Peter Clausen
2015-02-03 17:17 ` Russell King - ARM Linux [this message]
2015-02-03 17:26 ` Lars-Peter Clausen
2015-02-03 17:49 ` Lars-Peter Clausen
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