From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Jander <david.jander@protonic.nl>
Subject: Re: [PATCH] ASoC: imx-sgtl5000.c: Add support for
 specifying PDCR_TXRXEN
Date: Thu, 24 Apr 2014 15:35:48 +0200
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To: Markus Pargmann <mpa@pengutronix.de>
Cc: alsa-devel@alsa-project.org, Shawn Guo <shawn.guo@linaro.org>, Sascha Hauer <kernel@pengutronix.de>, David Jander <david@protonic.nl>
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On Thu, 24 Apr 2014 11:32:29 +0200
Markus Pargmann <mpa@pengutronix.de> wrote:

> On Thu, Apr 24, 2014 at 11:09:36AM +0200, David Jander wrote:
> > On Thu, 24 Apr 2014 10:46:30 +0200
> > Markus Pargmann <mpa@pengutronix.de> wrote:
> > 
> > > Hi,
> > > 
> > > On Wed, Apr 23, 2014 at 05:50:18PM +0200, David Jander wrote:
> > > > This enables effectively swapping RX/TX pins on the external audio port
> > > > 
> > > > Signed-off-by: David Jander <david@protonic.nl>
> > > > ---
> > > >  Documentation/devicetree/bindings/sound/imx-audio-sgtl5000.txt | 4
> > > > ++++ sound/soc/fsl/imx-sgtl5000.c                                   |
> > > > 5 ++++- 2 files changed, 8 insertions(+), 1 deletion(-)
> > > > 
> > > > diff --git
> > > > a/Documentation/devicetree/bindings/sound/imx-audio-sgtl5000.txt
> > > > b/Documentation/devicetree/bindings/sound/imx-audio-sgtl5000.txt index
> > > > e4acdd8..3afea85 100644 ---
> > > > a/Documentation/devicetree/bindings/sound/imx-audio-sgtl5000.txt +++
> > > > b/Documentation/devicetree/bindings/sound/imx-audio-sgtl5000.txt @@
> > > > -29,6 +29,10 @@ Required properties:
> > > >  - mux-int-port : The internal port of the i.MX audio muxer (AUDMUX)
> > > >  - mux-ext-port : The external port of the i.MX audio muxer
> > > >  
> > > > +Optional properties:
> > > > +- ext-port-txrxen : Flag. Set to swap RX/TX signals on external port
> > > > (set the
> > > > +  IMX_AUDMUX_V2_PDCR_TXRXEN bit in the PDC register of the external
> > > > port) +
> > > >  Note: The AUDMUX port numbering should start at 1, which is consistent
> > > > with hardware manual.
> > > 
> > > You could also try to use the simple sound card and use DT properties to
> > > setup audmux.
> > > 
> > > This is a configuration example for the audmux:
> > > &audmux {
> > >         status = "okay";
> > > 
> > >         aud4 {
> > >                 fsl,audmux-port = <MX31_AUDMUX_PORT4_SSI_PINS_4>;
> > >                 fsl,port-config = <
> > >                         (IMX_AUDMUX_V2_PTCR_SYN |
> > >                                 IMX_AUDMUX_V2_PTCR_TFSDIR |
> > >                                 IMX_AUDMUX_V2_PTCR_TFSEL(MX31_AUDMUX_PORT1_SSI0)
> > > | IMX_AUDMUX_V2_PTCR_TCLKDIR |
> > >                                 IMX_AUDMUX_V2_PTCR_TCSEL(MX31_AUDMUX_PORT1_SSI0))
> > >                         IMX_AUDMUX_V2_PDCR_RXDSEL(MX31_AUDMUX_PORT1_SSI0)
> > >                 >;
> > >         };
> > > };
> > 
> > I tried this, but the glue driver imx-sgtl5000.c changes the port settings
> > to its own knowledge.... and that includes hard-coded clearing of the
> > IMX_AUDMUX_V2_PDCR_TXRXEN bit.
> > 
> > How can I avoid the imx-sgtl5000.c driver from clearing the settings I
> > specify in the AUDMUX driver?
> 
> You can use the simple sound card (sound/soc/generic/simple-card.c). The
> sound card properties have to be described in the DT. See
> Documentation/devicetree/bindings/sound/simple-card.txt

This looks very interesting. I was not aware of this. Thanks!
I will see if this solves my problem.

Best regards,

-- 
David Jander
Protonic Holland.