ASoC: Intel: bytcr_rt5640: Add support for a second headphones output

Some devices (HP Elitepad 1000 G2) have a second headphones output
(1 on the dock, 2nd on the tablet itself) which is implemented through
the line-out output of the codec combined with an external hp-amp
which gets enabled through the codec's GPIO1 pin.

Add support for this through a new BYT_RT5640_LINEOUT_AS_HP2 quirk,
note users are expected to use this combined with the
BYT_RT5640_LINEOUT quirk. If that quirk is not set the new quirk is
ignored.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20210802142501.991985-5-hdegoede@redhat.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/boards/bytcr_rt5640.c

@@ -74,6 +74,7 @@ enum {
 #define BYT_RT5640_MCLK_25MHZ		BIT(23)
 #define BYT_RT5640_NO_SPEAKERS		BIT(24)
 #define BYT_RT5640_LINEOUT		BIT(25)
+#define BYT_RT5640_LINEOUT_AS_HP2	BIT(26)
 
 #define BYTCR_INPUT_DEFAULTS				\
 	(BYT_RT5640_IN3_MAP |				\
@@ -142,6 +143,8 @@ static void log_quirks(struct device *dev)
 		dev_info(dev, "quirk NO_SPEAKERS enabled\n");
 	if (byt_rt5640_quirk & BYT_RT5640_LINEOUT)
 		dev_info(dev, "quirk LINEOUT enabled\n");
+	if (byt_rt5640_quirk & BYT_RT5640_LINEOUT_AS_HP2)
+		dev_info(dev, "quirk LINEOUT_AS_HP2 enabled\n");
 	if (byt_rt5640_quirk & BYT_RT5640_DIFF_MIC)
 		dev_info(dev, "quirk DIFF_MIC enabled\n");
 	if (byt_rt5640_quirk & BYT_RT5640_SSP0_AIF1) {
@@ -287,12 +290,39 @@ static int platform_clock_control(struct snd_soc_dapm_widget *w,
 	return 0;
 }
 
+static int byt_rt5640_event_lineout(struct snd_soc_dapm_widget *w,
+			struct snd_kcontrol *k, int event)
+{
+	unsigned int gpio_ctrl3_val = RT5640_GP1_PF_OUT;
+	struct snd_soc_dai *codec_dai;
+
+	if (!(byt_rt5640_quirk & BYT_RT5640_LINEOUT_AS_HP2))
+		return 0;
+
+	/*
+	 * On devices which use line-out as a second headphones output,
+	 * the codec's GPIO1 pin is used to enable an external HP-amp.
+	 */
+
+	codec_dai = byt_rt5640_get_codec_dai(w->dapm);
+	if (!codec_dai)
+		return -EIO;
+
+	if (SND_SOC_DAPM_EVENT_ON(event))
+		gpio_ctrl3_val |= RT5640_GP1_OUT_HI;
+
+	snd_soc_component_update_bits(codec_dai->component, RT5640_GPIO_CTRL3,
+		RT5640_GP1_PF_MASK | RT5640_GP1_OUT_MASK, gpio_ctrl3_val);
+
+	return 0;
+}
+
 static const struct snd_soc_dapm_widget byt_rt5640_widgets[] = {
 	SND_SOC_DAPM_HP("Headphone", NULL),
 	SND_SOC_DAPM_MIC("Headset Mic", NULL),
 	SND_SOC_DAPM_MIC("Internal Mic", NULL),
 	SND_SOC_DAPM_SPK("Speaker", NULL),
-	SND_SOC_DAPM_LINE("Line Out", NULL),
+	SND_SOC_DAPM_LINE("Line Out", byt_rt5640_event_lineout),
 	SND_SOC_DAPM_SUPPLY("Platform Clock", SND_SOC_NOPM, 0, 0,
 			    platform_clock_control, SND_SOC_DAPM_PRE_PMU |
 			    SND_SOC_DAPM_POST_PMD),
@@ -1480,8 +1510,12 @@ static int snd_byt_rt5640_mc_probe(struct platform_device *pdev)
 		spk_type = "stereo";
 	}
 
-	if (byt_rt5640_quirk & BYT_RT5640_LINEOUT)
-		lineout_string = " cfg-lineout:1";
+	if (byt_rt5640_quirk & BYT_RT5640_LINEOUT) {
+		if (byt_rt5640_quirk & BYT_RT5640_LINEOUT_AS_HP2)
+			lineout_string = " cfg-hp2:lineout";
+		else
+			lineout_string = " cfg-lineout:1";
+	}
 
 	snprintf(byt_rt5640_components, sizeof(byt_rt5640_components),
 		 "cfg-spk:%d cfg-mic:%s aif:%d%s", cfg_spk,