ASoC: wm8994: Support constraining the maximum number of channels clocked
Some systems use the audio CODEC to clock a DAI with multiple data lines
in parallel, meaning that bit clocks are only required for a smaller number
of channels than data is sent for. In some cases providing the extra bit
clocks can take the other devices on the audio bus out of spec.
Support such systems by allowing a maximum number of channels to be
specified.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/codecs/wm8994.c b/sound/soc/codecs/wm8994.c
index c9bd445..318ea64 100644
--- a/sound/soc/codecs/wm8994.c
+++ b/sound/soc/codecs/wm8994.c
@@ -2656,6 +2656,8 @@
{
struct snd_soc_codec *codec = dai->codec;
struct wm8994_priv *wm8994 = snd_soc_codec_get_drvdata(codec);
+ struct wm8994 *control = wm8994->wm8994;
+ struct wm8994_pdata *pdata = &control->pdata;
int aif1_reg;
int aif2_reg;
int bclk_reg;
@@ -2723,7 +2725,14 @@
}
wm8994->channels[id] = params_channels(params);
- switch (params_channels(params)) {
+ if (pdata->max_channels_clocked[id] &&
+ wm8994->channels[id] > pdata->max_channels_clocked[id]) {
+ dev_dbg(dai->dev, "Constraining channels to %d from %d\n",
+ pdata->max_channels_clocked[id], wm8994->channels[id]);
+ wm8994->channels[id] = pdata->max_channels_clocked[id];
+ }
+
+ switch (wm8994->channels[id]) {
case 1:
case 2:
bclk_rate *= 2;
@@ -2745,7 +2754,7 @@
dev_dbg(dai->dev, "AIF%dCLK is %dHz, target BCLK %dHz\n",
dai->id, wm8994->aifclk[id], bclk_rate);
- if (params_channels(params) == 1 &&
+ if (wm8994->channels[id] == 1 &&
(snd_soc_read(codec, aif1_reg) & 0x18) == 0x18)
aif2 |= WM8994_AIF1_MONO;