[alsa-devel] [PATCH] ASoC: omap-mcbsp: On OMAP1 and OMAP2420 only 16bit format is supported

[Jarkko Nikula]

On Thu, Oct 25, 2018 at 04:48:24PM +0300, Peter Ujfalusi wrote:
> For samples sizes of 20/24/32 bit the DRR2/DXR2 registers must be used to
> receive or transmit the most significant part of the 32bit sample.
> We can not trick the system by using the DRR2/DXR2 register offset and use
> 32bit element size since these (and other McBSP) registers are 16bit ones.
> 
> We would need support for port_window in cyclic mode from the sDMA driver,
> but it is not straight forward as we would need to have the sDMA frame to
> cover the 32bit (DRR2+DRR1/DXR2+DXR1), but the frames must cover the ALSA
> period to be able to receive periodic interrupts.
> 
> Since the 32bit samples are not working (DMA timeout), just remove it in
> case we have McBSP with reg_size of 2.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi at ti.com>
> ---
> Hi,
> 
> I have noticed that on Nokia n810 32bit samples just don't work at all for audio
> 
> Regards,
> Peter
> 
>  sound/soc/omap/omap-mcbsp.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
I guess this same holds for OMAP1 too as it has 16-bit McBSP registers
too.

Acked-by: Jarkko Nikula <jarkko.nikula at bitmer.com>