ASoC: Implement interrupt driven microphone detection for WM8903

Support use of the WM8903 IRQ for reporting of microphone presence
and short detection.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>

3 files changed, 109 insertions, 3 deletions

diff --git a/include/sound/wm8903.h b/include/sound/wm8903.h
index 49bb1a844bfc..b4a0db2307ef 100644
--- a/include/sound/wm8903.h
+++ b/include/sound/wm8903.h
@@ -241,6 +241,8 @@ struct wm8903_platform_data {
          */
         u16 micdet_cfg;
 
+        int micdet_delay;      /* Delay after microphone detection (ms) */
+
         u32 gpio_cfg[5];       /* Default register values for GPIO pin mux */
 };
 
diff --git a/sound/soc/codecs/wm8903.c b/sound/soc/codecs/wm8903.c
index 7aa2adbe6fba..b5427b47d6fd 100644
--- a/sound/soc/codecs/wm8903.c
+++ b/sound/soc/codecs/wm8903.c
@@ -23,6 +23,7 @@
 #include <linux/i2c.h>
 #include <linux/platform_device.h>
 #include <sound/core.h>
+#include <sound/jack.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
 #include <sound/tlv.h>
@@ -223,6 +224,12 @@ struct wm8903_priv {
 
         struct completion wseq;
 
+        struct snd_soc_jack *mic_jack;
+        int mic_det;
+        int mic_short;
+        int mic_last_report;
+        int mic_delay;
+
         struct snd_pcm_substream *master_substream;
         struct snd_pcm_substream *slave_substream;
 };
@@ -1437,19 +1444,112 @@ static int wm8903_hw_params(struct snd_pcm_substream *substream,
         return 0;
 }
 
+/**
+ * wm8903_mic_detect - Enable microphone detection via the WM8903 IRQ
+ *
+ * @codec:  WM8903 codec
+ * @jack:   jack to report detection events on
+ * @det:    value to report for presence detection
+ * @shrt:   value to report for short detection
+ *
+ * Enable microphone detection via IRQ on the WM8903.  If GPIOs are
+ * being used to bring out signals to the processor then only platform
+ * data configuration is needed for WM8903 and processor GPIOs should
+ * be configured using snd_soc_jack_add_gpios() instead.
+ *
+ * The current threasholds for detection should be configured using
+ * micdet_cfg in the platform data.  Using this function will force on
+ * the microphone bias for the device.
+ */
+int wm8903_mic_detect(struct snd_soc_codec *codec, struct snd_soc_jack *jack,
+                      int det, int shrt)
+{
+        struct wm8903_priv *wm8903 = codec->private_data;
+        int irq_mask = 0;
+
+        dev_dbg(codec->dev, "Enabling microphone detection: %x %x\n",
+                det, shrt);
+
+        /* Store the configuration */
+        wm8903->mic_jack = jack;
+        wm8903->mic_det = det;
+        wm8903->mic_short = shrt;
+
+        /* Enable interrupts we've got a report configured for */
+        if (det)
+                irq_mask &= ~WM8903_MICDET_EINT;
+        if (shrt)
+                irq_mask &= ~WM8903_MICSHRT_EINT;
+
+        snd_soc_update_bits(codec, WM8903_INTERRUPT_STATUS_1_MASK,
+                            WM8903_MICDET_EINT | WM8903_MICSHRT_EINT,
+                            irq_mask);
+
+        /* Enable mic detection, this may not have been set through
+         * platform data (eg, if the defaults are OK). */
+        snd_soc_update_bits(codec, WM8903_WRITE_SEQUENCER_0,
+                            WM8903_WSEQ_ENA, WM8903_WSEQ_ENA);
+        snd_soc_update_bits(codec, WM8903_MIC_BIAS_CONTROL_0,
+                            WM8903_MICDET_ENA, WM8903_MICDET_ENA);
+
+        /* Force the microphone bias on; this will trigger an initial
+         * detection. */
+        snd_soc_dapm_force_enable_pin(codec, "Mic Bias");
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(wm8903_mic_detect);
+
 static irqreturn_t wm8903_irq(int irq, void *data)
 {
         struct wm8903_priv *wm8903 = data;
         struct snd_soc_codec *codec = &wm8903->codec;
-        int reg;
+        int mic_report;
+        int int_pol;
+        int int_val = 0;
+        int mask = ~snd_soc_read(codec, WM8903_INTERRUPT_STATUS_1_MASK);
 
-        reg = snd_soc_read(codec, WM8903_INTERRUPT_STATUS_1);
+        int_val = snd_soc_read(codec, WM8903_INTERRUPT_STATUS_1) & mask;
 
-        if (reg & WM8903_WSEQ_BUSY_EINT) {
+        if (int_val & WM8903_WSEQ_BUSY_EINT) {
                 dev_dbg(codec->dev, "Write sequencer done\n");
                 complete(&wm8903->wseq);
         }
 
+        /*
+         * The rest is microphone jack detection.  We need to manually
+         * invert the polarity of the interrupt after each event - to
+         * simplify the code keep track of the last state we reported
+         * and just invert the relevant bits in both the report and
+         * the polarity register.
+         */
+        mic_report = wm8903->mic_last_report;
+        int_pol = snd_soc_read(codec, WM8903_INTERRUPT_POLARITY_1);
+
+        if (int_val & WM8903_MICSHRT_EINT) {
+                dev_dbg(codec->dev, "Microphone short (pol=%x)\n", int_pol);
+
+                mic_report ^= wm8903->mic_short;
+                int_pol ^= WM8903_MICSHRT_INV;
+        }
+
+        if (int_val & WM8903_MICDET_EINT) {
+                dev_dbg(codec->dev, "Microphone detect (pol=%x)\n", int_pol);
+
+                mic_report ^= wm8903->mic_det;
+                int_pol ^= WM8903_MICDET_INV;
+
+                msleep(wm8903->mic_delay);
+        }
+
+        snd_soc_update_bits(codec, WM8903_INTERRUPT_POLARITY_1,
+                            WM8903_MICSHRT_INV | WM8903_MICDET_INV, int_pol);
+
+        snd_soc_jack_report(wm8903->mic_jack, mic_report,
+                            wm8903->mic_short | wm8903->mic_det);
+
+        wm8903->mic_last_report = mic_report;
+
         return IRQ_HANDLED;
 }
 
diff --git a/sound/soc/codecs/wm8903.h b/sound/soc/codecs/wm8903.h
index 8f19a2413785..ce384a2ad820 100644
--- a/sound/soc/codecs/wm8903.h
+++ b/sound/soc/codecs/wm8903.h
@@ -18,6 +18,10 @@
 extern struct snd_soc_dai wm8903_dai;
 extern struct snd_soc_codec_device soc_codec_dev_wm8903;
 
+extern int wm8903_mic_detect(struct snd_soc_codec *codec,
+                             struct snd_soc_jack *jack,
+                             int det, int shrt);
+
 #define WM8903_MCLK_DIV_2 1
 #define WM8903_CLK_SYS    2
 #define WM8903_BCLK       3