From: Arnd Bergmann <arnd@arndb.de>
To: Peter Griffin <peter.griffin@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        srinivas.kandagatla@gmail.com, maxime.coquelin@st.com,
        patrice.chotard@st.com, vinod.koul@intel.com, lee.jones@linaro.org,
        dmaengine@vger.kernel.org, devicetree@vger.kernel.org,
        broonie@kernel.org, ludovic.barre@st.com, arnaud.pouliquen@st.com
Subject: Re: [PATCH 09/18] ASoC: sti: Update DT example to match the driver code
Date: Tue, 26 Apr 2016 13:44:02 +0200
Message-ID: <5608365.uloflbeuqO@wuerfel>
User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; )
In-Reply-To: <20160426111532.GA5457@griffinp-ThinkPad-X1-Carbon-2nd>
References: <1461236675-10176-1-git-send-email-peter.griffin@linaro.org> <6161197.8XCk69TI60@wuerfel> <20160426111532.GA5457@griffinp-ThinkPad-X1-Carbon-2nd>
MIME-Version: 1.0
Content-Transfer-Encoding: 7Bit
Content-Type: text/plain; charset="us-ascii"
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1015
Lines: 26

On Tuesday 26 April 2016 12:15:32 Peter Griffin wrote:
> > 
> > > If not what would you recommend instead? 
> > 
> > It's still not clear to me what that bit in the syscfg register
> > is for. Given the error message about "sti-audio-clk-glue",
> > I suspect that this is actually a clock controller and that
> > it should be using the clock binding with a separate driver
> > instead of manipulating the regmap directly from the audio driver.
> 
> Luckily I do have the datasheet for the audio-glue sysconf register.
> 
> It says: -
> 
> [11:8] PCM_CLK_SEL: Selects the frequency synthesizer clock or the external
> PCM clock for each channel.
> 
> The driver only ever sets this to 1 which selects the frequency synthesizer
> clock. So the bitfield of the register which the driver is using (PCM_CLK_SEL)
> is a clock mux.

Ok, that sounds like it could be either a really simple clock driver
with just a few lines, or integrated into an existing clock driver
if you already have one for this syscon node.

	Arnd