ASoC: Enhance default WM8958 microphone detection

Actively manage the detection rate for microphones with WM8958, providing
improved power consumption and maximising the benefit from the hardware
debounce.

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

2 files changed, 111 insertions, 11 deletions

diff --git a/sound/soc/codecs/wm8994.c b/sound/soc/codecs/wm8994.c
index 207bccd156f1..027bf683efce 100644
--- a/sound/soc/codecs/wm8994.c
+++ b/sound/soc/codecs/wm8994.c
@@ -53,6 +53,56 @@ static int wm8994_retune_mobile_base[] = {
         WM8994_AIF2_EQ_GAINS_1,
 };
 
+static void wm8958_default_micdet(u16 status, void *data);
+
+static const struct {
+        int sysclk;
+        bool idle;
+        int start;
+        int rate;
+} wm8958_micd_rates[] = {
+        { 32768,       true,  1, 4 },
+        { 32768,       false, 1, 1 },
+        { 44100 * 256, true,  7, 6 },
+        { 44100 * 256, false, 7, 6 },
+};
+
+static void wm8958_micd_set_rate(struct snd_soc_codec *codec)
+{
+        struct wm8994_priv *wm8994 = snd_soc_codec_get_drvdata(codec);
+        int best, i, sysclk, val;
+        bool idle;
+
+        if (wm8994->jack_cb != wm8958_default_micdet)
+                return;
+
+        idle = !wm8994->jack_mic;
+
+        sysclk = snd_soc_read(codec, WM8994_CLOCKING_1);
+        if (sysclk & WM8994_SYSCLK_SRC)
+                sysclk = wm8994->aifclk[1];
+        else
+                sysclk = wm8994->aifclk[0];
+
+        best = 0;
+        for (i = 0; i < ARRAY_SIZE(wm8958_micd_rates); i++) {
+                if (wm8958_micd_rates[i].idle != idle)
+                        continue;
+                if (abs(wm8958_micd_rates[i].sysclk - sysclk) <
+                    abs(wm8958_micd_rates[best].sysclk - sysclk))
+                        best = i;
+                else if (wm8958_micd_rates[best].idle != idle)
+                        best = i;
+        }
+
+        val = wm8958_micd_rates[best].start << WM8958_MICD_BIAS_STARTTIME_SHIFT
+                | wm8958_micd_rates[best].rate << WM8958_MICD_RATE_SHIFT;
+
+        snd_soc_update_bits(codec, WM8958_MIC_DETECT_1,
+                            WM8958_MICD_BIAS_STARTTIME_MASK |
+                            WM8958_MICD_RATE_MASK, val);
+}
+
 static int wm8994_readable(struct snd_soc_codec *codec, unsigned int reg)
 {
         struct wm8994_priv *wm8994 = snd_soc_codec_get_drvdata(codec);
@@ -221,8 +271,10 @@ static int configure_clock(struct snd_soc_codec *codec)
          */
 
         /* If they're equal it doesn't matter which is used */
-        if (wm8994->aifclk[0] == wm8994->aifclk[1])
+        if (wm8994->aifclk[0] == wm8994->aifclk[1]) {
+                wm8958_micd_set_rate(codec);
                 return 0;
+        }
 
         if (wm8994->aifclk[0] < wm8994->aifclk[1])
                 new = WM8994_SYSCLK_SRC;
@@ -236,6 +288,8 @@ static int configure_clock(struct snd_soc_codec *codec)
 
         snd_soc_dapm_sync(&codec->dapm);
 
+        wm8958_micd_set_rate(codec);
+
         return 0;
 }
 
@@ -2987,21 +3041,56 @@ static void wm8958_default_micdet(u16 status, void *data)
 {
         struct snd_soc_codec *codec = data;
         struct wm8994_priv *wm8994 = snd_soc_codec_get_drvdata(codec);
-        int report = 0;
 
         /* If nothing present then clear our statuses */
-        if (!(status & WM8958_MICD_STS))
-                goto done;
+        if (!(status & WM8958_MICD_STS)) {
+                dev_dbg(codec->dev, "Detected open circuit\n");
+                wm8994->jack_mic = false;
+                wm8994->detecting = true;
+
+                wm8958_micd_set_rate(codec);
 
-        report = SND_JACK_MICROPHONE;
+                snd_soc_jack_report(wm8994->micdet[0].jack, 0,
+                                    SND_JACK_BTN_0 | SND_JACK_HEADSET);
+
+                return;
+        }
 
-        /* Everything else is buttons; just assign slots */
-        if (status & 0x1c)
-                report |= SND_JACK_BTN_0;
+        /* If the measurement is showing a high impedence we've got a
+         * microphone.
+         */
+        if (wm8994->detecting && (status & 0x600)) {
+                dev_dbg(codec->dev, "Detected microphone\n");
+
+                wm8994->detecting = false;
+                wm8994->jack_mic = true;
+
+                wm8958_micd_set_rate(codec);
+
+                snd_soc_jack_report(wm8994->micdet[0].jack, SND_JACK_HEADSET,
+                                    SND_JACK_HEADSET);
+        }
 
-done:
-        snd_soc_jack_report(wm8994->micdet[0].jack, report,
-                            SND_JACK_BTN_0 | SND_JACK_MICROPHONE);
+
+        if (wm8994->detecting && status & 0x4) {
+                dev_dbg(codec->dev, "Detected headphone\n");
+                wm8994->detecting = false;
+
+                wm8958_micd_set_rate(codec);
+
+                snd_soc_jack_report(wm8994->micdet[0].jack, SND_JACK_HEADPHONE,
+                                    SND_JACK_HEADSET);
+        }
+
+        /* Report short circuit as a button */
+        if (wm8994->jack_mic) {
+                if (status & 0x4)
+                        snd_soc_jack_report(wm8994->micdet[0].jack,
+                                            SND_JACK_BTN_0, SND_JACK_BTN_0);
+                else
+                        snd_soc_jack_report(wm8994->micdet[0].jack,
+                                            0, SND_JACK_BTN_0);
+        }
 }
 
 /**
@@ -3047,6 +3136,15 @@ int wm8958_mic_detect(struct snd_soc_codec *codec, struct snd_soc_jack *jack,
                 wm8994->jack_cb = cb;
                 wm8994->jack_cb_data = cb_data;
 
+                wm8994->detecting = true;
+                wm8994->jack_mic = false;
+
+                wm8958_micd_set_rate(codec);
+
+                /* Detect microphones and short circuits */
+                snd_soc_update_bits(codec, WM8958_MIC_DETECT_2,
+                                    WM8958_MICD_LVL_SEL_MASK, 0x41);
+
                 snd_soc_update_bits(codec, WM8958_MIC_DETECT_1,
                                     WM8958_MICD_ENA, WM8958_MICD_ENA);
         } else {
diff --git a/sound/soc/codecs/wm8994.h b/sound/soc/codecs/wm8994.h
index f4f1355efc82..1087425cbac0 100644
--- a/sound/soc/codecs/wm8994.h
+++ b/sound/soc/codecs/wm8994.h
@@ -126,6 +126,8 @@ struct wm8994_priv {
         struct soc_enum enh_eq_enum;
 
         struct wm8994_micdet micdet[2];
+        bool detecting;
+        bool jack_mic;
 
         wm8958_micdet_cb jack_cb;
         void *jack_cb_data;