[PATCH v4] ASoC: bcm2835: Add 8 channel (multitrack) capability

Charles Keepax ckeepax at opensource.wolfsonmicro.com
Wed Feb 15 01:24:39 PST 2017

On Wed, Feb 15, 2017 at 08:04:35AM +1100, Matt Flax wrote:
> This patch adds multitrack capability if in DSP mode A and the
> codec is master.
> In bcm2835_i2s_startup, snd_pcm_hw_constraint_single is used to set
> channels to 8 if both SND_SOC_DAIFMT_CBM_CFM and SND_SOC_DAIFMT_DSP_A
> are set. Otherwise, channels are set to 2. These settings are
> accomplished using the SNDRV_PCM_HW_PARAM_CHANNELS variable.
> In bcm2835_i2s_shutdown the channels are set to 2 by default.
> In bcm2835_i2s_hw_params, DSP mode A format is now an option.
> Before replicating the format variable (from ch2 to ch1) for
> register loading, requested channels are checked to be either 2 or 8.
> This can be expanded later to accomodate other channel counts if
> supported by the sound card hardware.
> Signed-off-by: Matt Flax <flatmax at flatmax.org>
> ---

Reviewed-by: Charles Keepax <ckeepax at opensource.wolfsonmicro.com>


More information about the linux-rpi-kernel mailing list