From: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
To: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: <linux-clk@vger.kernel.org>,
Michal Simek <michal.simek@xilinx.com>,
<devicetree@vger.kernel.org>,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@codeaurora.org>,
<linux-kernel@vger.kernel.org>,
"Rob Herring" <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] clk: zynq: avoid retrieving clock names from DT property
Date: Mon, 18 Jul 2016 10:22:44 -0700 [thread overview]
Message-ID: <20160718172244.GF3847@xsjsorenbubuntu> (raw)
In-Reply-To: <20160717161110.GY3847@xsjsorenbubuntu>
On Sun, 2016-07-17 at 09:11:10 -0700, Sören Brinkmann wrote:
> On Sun, 2016-07-17 at 00:15:23 +0900, Masahiro Yamada wrote:
> > The "clock-output-names" property is useful for generic clock
> > providers such as fixed-clock, fixed-factor-clock, etc.
> >
> > On the other hand, it should not be used for really SoC-specific
> > clock providers like this one. As you see in "enum zynq_clk" in
> > this driver, it is written as if it already knows all the clock
> > names. Besides, this is instantiated only once, so no clock name
> > conflict would happen even if the clock names are hard-coded in the
> > driver.
> >
> > The device tree (arch/arm/boot/dts/zynq-7000.dtsi) will be fixed
> > later.
> >
> > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
>
> IIRC, this was the only way to allow circular clock routing. E.g. there
> are use-cases that route an FCLK back into the PS to use it as input for
> the GEM. With the introduction of deferred probing this might all be
> possible now but it would be good to verify that this kind of circular
> clock routing still works with this change.
Yep, this breaks this kind of routing. E.g. if you remove the
clk-output-names from the DT and add an EMIO clock input like this:
clocks = <&clkc 15>;
clock-names = "gem1_emio_clk";
the code will no longer be able to correctly obtain the clock name for that input.
Sören
next prev parent reply other threads:[~2016-07-18 17:39 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-16 15:15 [PATCH] clk: zynq: avoid retrieving clock names from DT property Masahiro Yamada
2016-07-17 16:11 ` Sören Brinkmann
2016-07-18 17:22 ` Sören Brinkmann [this message]
2016-07-17 20:53 ` Rob Herring
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