ASoC: da7219: Add delays to capture path to remove DC offset noise

On some platforms it has been noted that a pop noise can be
witnessed when capturing audio, mainly for first time after a
headset jack has been inserted. This is due to a DC offset in the
Mic PGA and so to avoid this delays are required when powering
up the capture path.

This commit rectifies the problem by adding delays post Mic PGA and
post Mixin PGA. The post Mic PGA delay is determined based on
Mic Bias voltage, and is only applied the first time after a
headset jack is inserted.

Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/codecs/da7219-aad.c b/sound/soc/codecs/da7219-aad.c
index a49ab751a036c26ee89b414be0ba69f8b22db7aa..2c7d5088e6f2759aba90e469be2b3b8eb8b07dcb 100644 (file)
--- a/sound/soc/codecs/da7219-aad.c
+++ b/sound/soc/codecs/da7219-aad.c
@@ -59,6 +59,7 @@ static void da7219_aad_btn_det_work(struct work_struct *work)
                container_of(work, struct da7219_aad_priv, btn_det_work);
        struct snd_soc_component *component = da7219_aad->component;
        struct snd_soc_dapm_context *dapm = snd_soc_component_get_dapm(component);
+       struct da7219_priv *da7219 = snd_soc_component_get_drvdata(component);
        u8 statusa, micbias_ctrl;
        bool micbias_up = false;
        int retries = 0;
@@ -86,6 +87,8 @@ static void da7219_aad_btn_det_work(struct work_struct *work)
        if (retries >= DA7219_AAD_MICBIAS_CHK_RETRIES)
                dev_warn(component->dev, "Mic bias status check timed out");
 
+       da7219->micbias_on_event = true;
+
        /*
         * Mic bias pulse required to enable mic, must be done before enabling
         * button detection to prevent erroneous button readings.
@@ -439,6 +442,8 @@ static irqreturn_t da7219_aad_irq_thread(int irq, void *data)
                        snd_soc_component_update_bits(component, DA7219_ACCDET_CONFIG_1,
                                            DA7219_BUTTON_CONFIG_MASK, 0);
 
+                       da7219->micbias_on_event = false;
+
                        /* Disable mic bias */
                        snd_soc_dapm_disable_pin(dapm, "Mic Bias");
                        snd_soc_dapm_sync(dapm);

diff --git a/sound/soc/codecs/da7219.c b/sound/soc/codecs/da7219.c
index c0144f2f817468aaa1a7509e118c053f970a91c3..e46e9f4bc994681615b25066054d20867d3507cb 100644 (file)
--- a/sound/soc/codecs/da7219.c
+++ b/sound/soc/codecs/da7219.c
@@ -768,6 +768,30 @@ static const struct snd_kcontrol_new da7219_st_out_filtr_mix_controls[] = {
  * DAPM Events
  */
 
+static int da7219_mic_pga_event(struct snd_soc_dapm_widget *w,
+                               struct snd_kcontrol *kcontrol, int event)
+{
+       struct snd_soc_component *component = snd_soc_dapm_to_component(w->dapm);
+       struct da7219_priv *da7219 = snd_soc_component_get_drvdata(component);
+
+       switch (event) {
+       case SND_SOC_DAPM_POST_PMU:
+               if (da7219->micbias_on_event) {
+                       /*
+                        * Delay only for first capture after bias enabled to
+                        * avoid possible DC offset related noise.
+                        */
+                       da7219->micbias_on_event = false;
+                       msleep(da7219->mic_pga_delay);
+               }
+               break;
+       default:
+               break;
+       }
+
+       return 0;
+}
+
 static int da7219_dai_event(struct snd_soc_dapm_widget *w,
                            struct snd_kcontrol *kcontrol, int event)
 {
@@ -937,12 +961,12 @@ static const struct snd_soc_dapm_widget da7219_dapm_widgets[] = {
        SND_SOC_DAPM_INPUT("MIC"),
 
        /* Input PGAs */
-       SND_SOC_DAPM_PGA("Mic PGA", DA7219_MIC_1_CTRL,
-                        DA7219_MIC_1_AMP_EN_SHIFT, DA7219_NO_INVERT,
-                        NULL, 0),
-       SND_SOC_DAPM_PGA("Mixin PGA", DA7219_MIXIN_L_CTRL,
-                        DA7219_MIXIN_L_AMP_EN_SHIFT, DA7219_NO_INVERT,
-                        NULL, 0),
+       SND_SOC_DAPM_PGA_E("Mic PGA", DA7219_MIC_1_CTRL,
+                          DA7219_MIC_1_AMP_EN_SHIFT, DA7219_NO_INVERT,
+                          NULL, 0, da7219_mic_pga_event, SND_SOC_DAPM_POST_PMU),
+       SND_SOC_DAPM_PGA_E("Mixin PGA", DA7219_MIXIN_L_CTRL,
+                          DA7219_MIXIN_L_AMP_EN_SHIFT, DA7219_NO_INVERT,
+                          NULL, 0, da7219_settling_event, SND_SOC_DAPM_POST_PMU),
 
        /* Input Filters */
        SND_SOC_DAPM_ADC("ADC", NULL, DA7219_ADC_L_CTRL, DA7219_ADC_L_EN_SHIFT,
@@ -1847,6 +1871,14 @@ static void da7219_handle_pdata(struct snd_soc_component *component)
 
                snd_soc_component_write(component, DA7219_MICBIAS_CTRL, micbias_lvl);
 
+               /*
+                * Calculate delay required to compensate for DC offset in
+                * Mic PGA, based on Mic Bias voltage.
+                */
+               da7219->mic_pga_delay =  DA7219_MIC_PGA_BASE_DELAY +
+                                       (pdata->micbias_lvl *
+                                        DA7219_MIC_PGA_OFFSET_DELAY);
+
                /* Mic */
                switch (pdata->mic_amp_in_sel) {
                case DA7219_MIC_AMP_IN_SEL_DIFF:

diff --git a/sound/soc/codecs/da7219.h b/sound/soc/codecs/da7219.h
index 1b00023e33cd6761c2fac0c851eb040933c4ce74..3a006862f0e791b486ad009a83b1335a0a779c29 100644 (file)
--- a/sound/soc/codecs/da7219.h
+++ b/sound/soc/codecs/da7219.h
@@ -781,8 +781,10 @@
 #define DA7219_SYS_STAT_CHECK_DELAY    50
 
 /* Power up/down Delays */
-#define DA7219_SETTLING_DELAY  40
-#define DA7219_MIN_GAIN_DELAY  30
+#define DA7219_SETTLING_DELAY          40
+#define DA7219_MIN_GAIN_DELAY          30
+#define DA7219_MIC_PGA_BASE_DELAY      100
+#define DA7219_MIC_PGA_OFFSET_DELAY    40
 
 enum da7219_clk_src {
        DA7219_CLKSRC_MCLK = 0,
@@ -828,6 +830,8 @@ struct da7219_priv {
 
        bool master;
        bool alc_en;
+       bool micbias_on_event;
+       unsigned int mic_pga_delay;
        u8 gain_ramp_ctrl;
 };