On 14/02/17 20:32, Charles Keepax wrote:
On Mon, Feb 13, 2017 at 10:27:15AM +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_minmax is used to set
max channels to 8 if both SND_SOC_DAIFMT_CBM_CFM and
SND_SOC_DAIFMT_DSP_A are set. Otherwise, max channels is set to 2.
Min channels is always set to 2. These settings are accomplished
using the SNDRV_PCM_HW_PARAM_CHANNELS variable.
In bcm2835_i2s_shutdown max channels is 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 expaneded later to accomodate other channel counts if
supported by the sound card hardware.
Signed-off-by: Matt Flax <flatmax@xxxxxxxxxxx>
---
<snip>
@@ -312,6 +313,7 @@ static int bcm2835_i2s_hw_params(struct snd_pcm_substream *substream,
switch (params_channels(params)) {
case 2:
+ case 8:
format = BCM2835_I2S_CH1(format) | BCM2835_I2S_CH2(format);
format |= BCM2835_I2S_CH1(BCM2835_I2S_CHPOS(ch1pos));
format |= BCM2835_I2S_CH2(BCM2835_I2S_CHPOS(ch2pos));
@@ -526,7 +528,16 @@ static int bcm2835_i2s_startup(struct snd_pcm_substream *substream,
regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
BCM2835_I2S_STBY, BCM2835_I2S_STBY);
- return 0;
+ /* Set the max channels to 8 if the codec is master and
+ * we are in DSP A mode. Otherwise only allow 2 channels.
+ */
+ if (dev->fmt &
+ (SND_SOC_DAIFMT_CBM_CFM | SND_SOC_DAIFMT_DSP_A))
+ return snd_pcm_hw_constraint_minmax(substream->runtime,
+ SNDRV_PCM_HW_PARAM_CHANNELS, 2, 8);
Would it be worth using snd_pcm_hw_constraint_list here? We are
going to error out of hw_params if the user requests anything
other than 2 or 8 channels so we should probably just constrain
to those two.
Actually, I didn't think of this, but there is no reason to have 2
channels available in DSP A mode with codec master. I will change this
to constrain the channels to 8.
+ else
+ return snd_pcm_hw_constraint_minmax(substream->runtime,
+ SNDRV_PCM_HW_PARAM_CHANNELS, 2, 2);
snd_pcm_hw_constraint_single, it's exactly the same thing but I
guess we should probably use the helper if it exists.
Will do.
}
static void bcm2835_i2s_shutdown(struct snd_pcm_substream *substream,
@@ -549,6 +560,10 @@ static void bcm2835_i2s_shutdown(struct snd_pcm_substream *substream,
* not stop the clock when SND_SOC_DAIFMT_CONT
*/
bcm2835_i2s_stop_clock(dev);
+
+ /* Default to 2 channels */
+ snd_pcm_hw_constraint_minmax(substream->runtime,
+ SNDRV_PCM_HW_PARAM_CHANNELS, 2, 2);
}
ditto.
Will do.
Thanks,
Charles
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