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ASoC: arizona: Implement stability check for LHPF coefficients

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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>
This commit is contained in:
Charles Keepax
2015-06-25 09:35:12 +01:00
committed by Mark Brown
parent c05d9a8c7f
commit 5f8e671a49
5 changed files with 38 additions and 12 deletions
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17
sound/soc/codecs/arizona.c
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@@ -2372,6 +2372,23 @@ out:
}
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");