For correct operation of the digital filtering and other processing on the WM8741, the user must ensure the correct value of OSR[1:0] is set at all times.[1] Hence, depending the selected sampling rate, set the OSR (over- sampling rate) mode in hw_params().
References: [1] "WM8741 Data Sheet"
Signed-off-by: Sergej Sawazki sergej@taudac.com --- Changes in v2: * Using update_bits() rather than write().
sound/soc/codecs/wm8741.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/sound/soc/codecs/wm8741.c b/sound/soc/codecs/wm8741.c index fdda83b..a4b8c45 100644 --- a/sound/soc/codecs/wm8741.c +++ b/sound/soc/codecs/wm8741.c @@ -196,7 +196,7 @@ static int wm8741_hw_params(struct snd_pcm_substream *substream, { struct snd_soc_component *component = dai->component; struct wm8741_priv *wm8741 = snd_soc_component_get_drvdata(component); - unsigned int iface; + unsigned int iface, mode; int i;
/* The set of sample rates that can be supported depends on the @@ -240,11 +240,21 @@ static int wm8741_hw_params(struct snd_pcm_substream *substream, return -EINVAL; }
+ /* oversampling rate */ + if (params_rate(params) > 96000) + mode = 0x40; + else if (params_rate(params) > 48000) + mode = 0x20; + else + mode = 0x00; + dev_dbg(component->dev, "wm8741_hw_params: bit size param = %d, rate param = %d", params_width(params), params_rate(params));
snd_soc_component_update_bits(component, WM8741_FORMAT_CONTROL, WM8741_IWL_MASK, iface); + snd_soc_component_update_bits(component, WM8741_MODE_CONTROL_1, WM8741_OSR_MASK, + mode);
return 0; }