ASoC: wm8994: Actively discharge idle MICBIAS with jack detect

This minimises the chance of any external capacitors that are fitted
being discharged into headphones as they insert.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

diff --git a/sound/soc/codecs/wm8994.c b/sound/soc/codecs/wm8994.c
index e9a405a..77085c1 100644 (file)
--- a/sound/soc/codecs/wm8994.c
+++ b/sound/soc/codecs/wm8994.c
@@ -3224,6 +3224,9 @@ static irqreturn_t wm1811_jackdet_irq(int irq, void *data)
                snd_soc_jack_report(wm8994->micdet[0].jack,
                                    SND_JACK_MECHANICAL, SND_JACK_MECHANICAL);
 
+               snd_soc_update_bits(codec, WM8958_MICBIAS2,
+                                   WM8958_MICB2_DISCH, 0);
+
                /*
                 * Start off measument of microphone impedence to find
                 * out what's actually there.
@@ -3235,6 +3238,9 @@ static irqreturn_t wm1811_jackdet_irq(int irq, void *data)
        } else {
                dev_dbg(codec->dev, "Jack not detected\n");
 
+               snd_soc_update_bits(codec, WM8958_MICBIAS2,
+                                   WM8958_MICB2_DISCH, WM8958_MICB2_DISCH);
+
                snd_soc_jack_report(wm8994->micdet[0].jack, 0,
                                    SND_JACK_MECHANICAL | SND_JACK_HEADSET |
                                    wm8994->btn_mask);
@@ -3320,6 +3326,9 @@ int wm8958_mic_detect(struct snd_soc_codec *codec, struct snd_soc_jack *jack,
                 * otherwise jump straight to microphone detection.
                 */
                if (wm8994->jackdet) {
+                       snd_soc_update_bits(codec, WM8958_MICBIAS2,
+                                           WM8958_MICB2_DISCH,
+                                           WM8958_MICB2_DISCH);
                        snd_soc_update_bits(codec, WM8994_LDO_1,
                                            WM8994_LDO1_DISCH, 0);
                        wm1811_jackdet_set_mode(codec,