Re: [PATCH v9 3/4] ASoC: tda998x: add a codec to the HDMI transmitter

[Andrew Jackson <Andrew.Jackson@arm.com>]

On 01/07/15 10:51, Jean-Francois Moine wrote:
> This patch adds a CODEC to the NXP TDA998x HDMI transmitter.
> 
> The CODEC handles both I2S and S/PDIF inputs.
> It maintains the audio format and rate constraints according
> to the HDMI device parameters (EDID) and sets dynamically the input
> ports in the TDA998x I2C driver on start/stop audio streaming.
> 
> Signed-off-by: Jean-Francois Moine <moinejf@free.fr>
> ---

[snip]

> +static int tda998x_codec_startup(struct snd_pcm_substream *substream,
> +                                struct snd_soc_dai *dai)
> +{
> +       struct snd_pcm_runtime *runtime = substream->runtime;
> +       struct snd_pcm_hw_constraint_list *rate_constraints;
> +       u8 *sad;                /* Short Audio Descriptor (3 bytes) */

[...]

> +       snd_pcm_hw_constraint_minmax(runtime,
> +                               SNDRV_PCM_HW_PARAM_CHANNELS,
> +                               1, sad[SAD_MX_CHAN_I]);

In the light of our discussions elsewhere [1], shouldn't this
be constrained by the number of hardware channels that the TDA998x
supports too?  That is, the maximum number of channels should
be the lesser of sd[SAD_MX_CHAN_I] and number_of_I2S channels 
(or S/PDIF channels if so configured).

	Andrew

[1] http://mailman.alsa-project.org/pipermail/alsa-devel/2015-January/086090.html