ASoC: arizona: Implement stability check for LHPF coefficients
Specifying unstable coefficients for the low/high pass filters can have
a severe impact on the audio. This patchs adds a stability check on the
coefficients written to the low/high pass filter block to prevent this.
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/codecs/arizona.c b/sound/soc/codecs/arizona.c
index 3996786..a88202d 100644
--- a/sound/soc/codecs/arizona.c
+++ b/sound/soc/codecs/arizona.c
@@ -2372,6 +2372,23 @@
}
EXPORT_SYMBOL_GPL(arizona_eq_coeff_put);
+int arizona_lhpf_coeff_put(struct snd_kcontrol *kcontrol,
+ struct snd_ctl_elem_value *ucontrol)
+{
+ struct snd_soc_codec *codec = snd_soc_kcontrol_codec(kcontrol);
+ struct arizona *arizona = dev_get_drvdata(codec->dev->parent);
+ __be16 *data = (__be16 *)ucontrol->value.bytes.data;
+ s16 val = be16_to_cpu(*data);
+
+ if (abs(val) >= 4096) {
+ dev_err(arizona->dev, "Rejecting unstable LHPF coefficients\n");
+ return -EINVAL;
+ }
+
+ return snd_soc_bytes_put(kcontrol, ucontrol);
+}
+EXPORT_SYMBOL_GPL(arizona_lhpf_coeff_put);
+
MODULE_DESCRIPTION("ASoC Wolfson Arizona class device support");
MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
MODULE_LICENSE("GPL");