ASoC: sgtl5000: Improve VAG power and mute control

VAG power control is improved to fit the manual [1]. This patch fixes as
minimum one bug: if customer muxes Headphone to Line-In right after boot,
the VAG power remains off that leads to poor sound quality from line-in.

I.e. after boot:
  - Connect sound source to Line-In jack;
  - Connect headphone to HP jack;
  - Run following commands:
  $ amixer set 'Headphone' 80%
  $ amixer set 'Headphone Mux' LINE_IN

Change VAG power on/off control according to the following algorithm:
  - turn VAG power ON on the 1st incoming event.
  - keep it ON if there is any active VAG consumer (ADC/DAC/HP/Line-In).
  - turn VAG power OFF when there is the latest consumer's pre-down event
    come.
  - always delay after VAG power OFF to avoid pop.
  - delay after VAG power ON if the initiative consumer is Line-In, this
    prevents pop during line-in muxing.

According to the data sheet [1], to avoid any pops/clicks,
the outputs should be muted during input/output
routing changes.

[1] https://www.nxp.com/docs/en/data-sheet/SGTL5000.pdf

Cc: stable@vger.kernel.org
Fixes: 9b34e6cc3bc2 ("ASoC: Add Freescale SGTL5000 codec support")
Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Reviewed-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20190719100524.23300-3-oleksandr.suvorov@toradex.com
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 194 insertions, 30 deletions

diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c
index a6a4748c97f9..34cc85e49003 100644
--- a/sound/soc/codecs/sgtl5000.c
+++ b/sound/soc/codecs/sgtl5000.c
@@ -31,6 +31,13 @@
 #define SGTL5000_DAP_REG_OFFSET 0x0100
 #define SGTL5000_MAX_REG_OFFSET 0x013A
 
+/* Delay for the VAG ramp up */
+#define SGTL5000_VAG_POWERUP_DELAY 500 /* ms */
+/* Delay for the VAG ramp down */
+#define SGTL5000_VAG_POWERDOWN_DELAY 500 /* ms */
+
+#define SGTL5000_OUTPUTS_MUTE (SGTL5000_HP_MUTE | SGTL5000_LINE_OUT_MUTE)
+
 /* default value of sgtl5000 registers */
 static const struct reg_default sgtl5000_reg_defaults[] = {
         { SGTL5000_CHIP_DIG_POWER,              0x0000 },
@@ -123,6 +130,13 @@ enum  {
         I2S_SCLK_STRENGTH_HIGH,
 };
 
+enum {
+        HP_POWER_EVENT,
+        DAC_POWER_EVENT,
+        ADC_POWER_EVENT,
+        LAST_POWER_EVENT = ADC_POWER_EVENT
+};
+
 /* sgtl5000 private structure in codec */
 struct sgtl5000_priv {
         int sysclk;     /* sysclk rate */
@@ -137,8 +151,109 @@ struct sgtl5000_priv {
         u8 micbias_voltage;
         u8 lrclk_strength;
         u8 sclk_strength;
+        u16 mute_state[LAST_POWER_EVENT + 1];
 };
 
+static inline int hp_sel_input(struct snd_soc_component *component)
+{
+        return (snd_soc_component_read32(component, SGTL5000_CHIP_ANA_CTRL) &
+                SGTL5000_HP_SEL_MASK) >> SGTL5000_HP_SEL_SHIFT;
+}
+
+static inline u16 mute_output(struct snd_soc_component *component,
+                              u16 mute_mask)
+{
+        u16 mute_reg = snd_soc_component_read32(component,
+                                              SGTL5000_CHIP_ANA_CTRL);
+
+        snd_soc_component_update_bits(component, SGTL5000_CHIP_ANA_CTRL,
+                            mute_mask, mute_mask);
+        return mute_reg;
+}
+
+static inline void restore_output(struct snd_soc_component *component,
+                                  u16 mute_mask, u16 mute_reg)
+{
+        snd_soc_component_update_bits(component, SGTL5000_CHIP_ANA_CTRL,
+                mute_mask, mute_reg);
+}
+
+static void vag_power_on(struct snd_soc_component *component, u32 source)
+{
+        if (snd_soc_component_read32(component, SGTL5000_CHIP_ANA_POWER) &
+            SGTL5000_VAG_POWERUP)
+                return;
+
+        snd_soc_component_update_bits(component, SGTL5000_CHIP_ANA_POWER,
+                            SGTL5000_VAG_POWERUP, SGTL5000_VAG_POWERUP);
+
+        /* When VAG powering on to get local loop from Line-In, the sleep
+         * is required to avoid loud pop.
+         */
+        if (hp_sel_input(component) == SGTL5000_HP_SEL_LINE_IN &&
+            source == HP_POWER_EVENT)
+                msleep(SGTL5000_VAG_POWERUP_DELAY);
+}
+
+static int vag_power_consumers(struct snd_soc_component *component,
+                               u16 ana_pwr_reg, u32 source)
+{
+        int consumers = 0;
+
+        /* count dac/adc consumers unconditional */
+        if (ana_pwr_reg & SGTL5000_DAC_POWERUP)
+                consumers++;
+        if (ana_pwr_reg & SGTL5000_ADC_POWERUP)
+                consumers++;
+
+        /*
+         * If the event comes from HP and Line-In is selected,
+         * current action is 'DAC to be powered down'.
+         * As HP_POWERUP is not set when HP muxed to line-in,
+         * we need to keep VAG power ON.
+         */
+        if (source == HP_POWER_EVENT) {
+                if (hp_sel_input(component) == SGTL5000_HP_SEL_LINE_IN)
+                        consumers++;
+        } else {
+                if (ana_pwr_reg & SGTL5000_HP_POWERUP)
+                        consumers++;
+        }
+
+        return consumers;
+}
+
+static void vag_power_off(struct snd_soc_component *component, u32 source)
+{
+        u16 ana_pwr = snd_soc_component_read32(component,
+                                             SGTL5000_CHIP_ANA_POWER);
+
+        if (!(ana_pwr & SGTL5000_VAG_POWERUP))
+                return;
+
+        /*
+         * This function calls when any of VAG power consumers is disappearing.
+         * Thus, if there is more than one consumer at the moment, as minimum
+         * one consumer will definitely stay after the end of the current
+         * event.
+         * Don't clear VAG_POWERUP if 2 or more consumers of VAG present:
+         * - LINE_IN (for HP events) / HP (for DAC/ADC events)
+         * - DAC
+         * - ADC
+         * (the current consumer is disappearing right now)
+         */
+        if (vag_power_consumers(component, ana_pwr, source) >= 2)
+                return;
+
+        snd_soc_component_update_bits(component, SGTL5000_CHIP_ANA_POWER,
+                SGTL5000_VAG_POWERUP, 0);
+        /* In power down case, we need wait 400-1000 ms
+         * when VAG fully ramped down.
+         * As longer we wait, as smaller pop we've got.
+         */
+        msleep(SGTL5000_VAG_POWERDOWN_DELAY);
+}
+
 /*
  * mic_bias power on/off share the same register bits with
  * output impedance of mic bias, when power on mic bias, we
@@ -170,36 +285,46 @@ static int mic_bias_event(struct snd_soc_dapm_widget *w,
         return 0;
 }
 
-/*
- * As manual described, ADC/DAC only works when VAG powerup,
- * So enabled VAG before ADC/DAC up.
- * In power down case, we need wait 400ms when vag fully ramped down.
- */
-static int power_vag_event(struct snd_soc_dapm_widget *w,
-        struct snd_kcontrol *kcontrol, int event)
+static int vag_and_mute_control(struct snd_soc_component *component,
+                                 int event, int event_source)
 {
-        struct snd_soc_component *component = snd_soc_dapm_to_component(w->dapm);
-        const u32 mask = SGTL5000_DAC_POWERUP | SGTL5000_ADC_POWERUP;
+        static const u16 mute_mask[] = {
+                /*
+                 * Mask for HP_POWER_EVENT.
+                 * Muxing Headphones have to be wrapped with mute/unmute
+                 * headphones only.
+                 */
+                SGTL5000_HP_MUTE,
+                /*
+                 * Masks for DAC_POWER_EVENT/ADC_POWER_EVENT.
+                 * Muxing DAC or ADC block have to wrapped with mute/unmute
+                 * both headphones and line-out.
+                 */
+                SGTL5000_OUTPUTS_MUTE,
+                SGTL5000_OUTPUTS_MUTE
+        };
+
+        struct sgtl5000_priv *sgtl5000 =
+                snd_soc_component_get_drvdata(component);
 
         switch (event) {
+        case SND_SOC_DAPM_PRE_PMU:
+                sgtl5000->mute_state[event_source] =
+                        mute_output(component, mute_mask[event_source]);
+                break;
         case SND_SOC_DAPM_POST_PMU:
-                snd_soc_component_update_bits(component, SGTL5000_CHIP_ANA_POWER,
-                        SGTL5000_VAG_POWERUP, SGTL5000_VAG_POWERUP);
-                msleep(400);
+                vag_power_on(component, event_source);
+                restore_output(component, mute_mask[event_source],
+                               sgtl5000->mute_state[event_source]);
                 break;
-
         case SND_SOC_DAPM_PRE_PMD:
-                /*
-                 * Don't clear VAG_POWERUP, when both DAC and ADC are
-                 * operational to prevent inadvertently starving the
-                 * other one of them.
-                 */
-                if ((snd_soc_component_read32(component, SGTL5000_CHIP_ANA_POWER) &
-                                mask) != mask) {
-                        snd_soc_component_update_bits(component, SGTL5000_CHIP_ANA_POWER,
-                                SGTL5000_VAG_POWERUP, 0);
-                        msleep(400);
-                }
+                sgtl5000->mute_state[event_source] =
+                        mute_output(component, mute_mask[event_source]);
+                vag_power_off(component, event_source);
+                break;
+        case SND_SOC_DAPM_POST_PMD:
+                restore_output(component, mute_mask[event_source],
+                               sgtl5000->mute_state[event_source]);
                 break;
         default:
                 break;
@@ -208,6 +333,41 @@ static int power_vag_event(struct snd_soc_dapm_widget *w,
         return 0;
 }
 
+/*
+ * Mute Headphone when power it up/down.
+ * Control VAG power on HP power path.
+ */
+static int headphone_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);
+
+        return vag_and_mute_control(component, event, HP_POWER_EVENT);
+}
+
+/* As manual describes, ADC/DAC powering up/down requires
+ * to mute outputs to avoid pops.
+ * Control VAG power on ADC/DAC power path.
+ */
+static int adc_updown_depop(struct snd_soc_dapm_widget *w,
+        struct snd_kcontrol *kcontrol, int event)
+{
+        struct snd_soc_component *component =
+                snd_soc_dapm_to_component(w->dapm);
+
+        return vag_and_mute_control(component, event, ADC_POWER_EVENT);
+}
+
+static int dac_updown_depop(struct snd_soc_dapm_widget *w,
+        struct snd_kcontrol *kcontrol, int event)
+{
+        struct snd_soc_component *component =
+                snd_soc_dapm_to_component(w->dapm);
+
+        return vag_and_mute_control(component, event, DAC_POWER_EVENT);
+}
+
 /* input sources for ADC */
 static const char *adc_mux_text[] = {
         "MIC_IN", "LINE_IN"
@@ -280,7 +440,10 @@ static const struct snd_soc_dapm_widget sgtl5000_dapm_widgets[] = {
                             mic_bias_event,
                             SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_PRE_PMD),
 
-        SND_SOC_DAPM_PGA("HP", SGTL5000_CHIP_ANA_POWER, 4, 0, NULL, 0),
+        SND_SOC_DAPM_PGA_E("HP", SGTL5000_CHIP_ANA_POWER, 4, 0, NULL, 0,
+                           headphone_pga_event,
+                           SND_SOC_DAPM_PRE_POST_PMU |
+                           SND_SOC_DAPM_PRE_POST_PMD),
         SND_SOC_DAPM_PGA("LO", SGTL5000_CHIP_ANA_POWER, 0, 0, NULL, 0),
 
         SND_SOC_DAPM_MUX("Capture Mux", SND_SOC_NOPM, 0, 0, &adc_mux),
@@ -301,11 +464,12 @@ static const struct snd_soc_dapm_widget sgtl5000_dapm_widgets[] = {
                                 0, SGTL5000_CHIP_DIG_POWER,
                                 1, 0),
 
-        SND_SOC_DAPM_ADC("ADC", "Capture", SGTL5000_CHIP_ANA_POWER, 1, 0),
-        SND_SOC_DAPM_DAC("DAC", "Playback", SGTL5000_CHIP_ANA_POWER, 3, 0),
-
-        SND_SOC_DAPM_PRE("VAG_POWER_PRE", power_vag_event),
-        SND_SOC_DAPM_POST("VAG_POWER_POST", power_vag_event),
+        SND_SOC_DAPM_ADC_E("ADC", "Capture", SGTL5000_CHIP_ANA_POWER, 1, 0,
+                           adc_updown_depop, SND_SOC_DAPM_PRE_POST_PMU |
+                           SND_SOC_DAPM_PRE_POST_PMD),
+        SND_SOC_DAPM_DAC_E("DAC", "Playback", SGTL5000_CHIP_ANA_POWER, 3, 0,
+                           dac_updown_depop, SND_SOC_DAPM_PRE_POST_PMU |
+                           SND_SOC_DAPM_PRE_POST_PMD),
 };
 
 /* routes for sgtl5000 */