[alsa-devel] [PATCH 2/2] ARM: dts: imx6: remove non-working spdif rxtx4 and rxtx6 clocks

[Nicolin Chen]

On Mon, Jun 16, 2014 at 02:39:45AM +0300, Anssi Hannula wrote:
> The S/PDIF rxtx4 and rxtx6 clock inputs are "ESAI_HCKT" and "MLB clock",
> respectively, according to the SoC documentation, and they are currently
> mapped to clocks "esai" and "mlb".
> 
> However, they do not seem to actually work correctly. Testing on a
> Cubox-i system with fsl_spdif driver forced to select one of those as
> input will result in I/O errors on audio playback, which I believe means
> missing clock signal.
> 
> Possibly the "ESAI_HCKT" and "MLB clock" refer to some other clocks
> related to ESAI and MLB, or we are missing something else.

Yes, they are actually the clocks from outside of SoC: HCKT of ESAI could
be set as an input PAD while MLB clock is the bit clock used by MLB.

> Since audio playback will not work if fsl_spdif selects these clocks
> (which happens rarely), set the inputs do dummy clocks, at least for
> now.
> 
> Signed-off-by: Anssi Hannula <anssi.hannula at iki.fi>
> Cc: Nicolin Chen <Guangyu.Chen at freescale.com>

Acked, thank you.
Nicolin

> Cc: Mark Brown <broonie at kernel.org>
> ---
> 
> Does anyone know what is wrong here? i.e. are the clocks actually wrong
> or are we maybe doing something wrong with their setup?
> 
> Also, is this the correct way to "fix" the issue, or should we rather
> modify the driver to not select rxtx4/rxtx6 for now (assuming no one knows
> how to fix this properly, of course)?
> (I haven't been involved with device trees before)
> 
> 
>  arch/arm/boot/dts/imx6qdl.dtsi | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/imx6qdl.dtsi b/arch/arm/boot/dts/imx6qdl.dtsi
> index 3aef9a2f5fda..f0d1c2334952 100644
> --- a/arch/arm/boot/dts/imx6qdl.dtsi
> +++ b/arch/arm/boot/dts/imx6qdl.dtsi
> @@ -182,8 +182,8 @@
>  					dma-names = "rx", "tx";
>  					clocks = <&clks 197>, <&clks 3>,
>  						 <&clks 197>, <&clks 0>,
> -						 <&clks 0>,   <&clks 118>,
> -						 <&clks 0>,  <&clks 139>,
> +						 <&clks 0>,   <&clks 0>,
> +						 <&clks 0>,  <&clks 0>,
>  						 <&clks 0>;
>  					clock-names = "core",  "rxtx0",
>  						      "rxtx1", "rxtx2",
> -- 
> 1.8.4.5
>