[PATCH 2/3] ASoC: sun50i-codec-analog: Add support for internal bias

[Samuel Holland]

From: Arnaud Ferraris <arnaud.ferraris at collabora.com>

In order to properly bias headset microphones, there should be a pull-up
resistor between pins HBIAS and MIC2P. This can be an external resistor,
but the codec also provides an internal 2.2K resistor which is enabled
by a register.

This patch enables or disables the internal bias resistor based on a
device tree property.

Signed-off-by: Arnaud Ferraris <arnaud.ferraris at collabora.com>
[Samuel: split binding and implementation patches]
Signed-off-by: Samuel Holland <samuel at sholland.org>
---

 sound/soc/sunxi/sun50i-codec-analog.c | 29 +++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/sound/soc/sunxi/sun50i-codec-analog.c b/sound/soc/sunxi/sun50i-codec-analog.c
index a41e25ad0aaf..699a5a318875 100644
--- a/sound/soc/sunxi/sun50i-codec-analog.c
+++ b/sound/soc/sunxi/sun50i-codec-analog.c
@@ -117,8 +117,13 @@
 #define SUN50I_ADDA_HS_MBIAS_CTRL_MMICBIASEN	7
 
 #define SUN50I_ADDA_JACK_MIC_CTRL	0x1d
+#define SUN50I_ADDA_JACK_MIC_CTRL_INNERRESEN	6
 #define SUN50I_ADDA_JACK_MIC_CTRL_HMICBIASEN	5
 
+struct sun50i_codec_analog {
+	bool	internal_bias_resistor;
+};
+
 /* mixer controls */
 static const struct snd_kcontrol_new sun50i_a64_codec_mixer_controls[] = {
 	SOC_DAPM_DOUBLE_R("Mic1 Playback Switch",
@@ -471,6 +476,18 @@ static const struct snd_soc_dapm_route sun50i_a64_codec_routes[] = {
 	{ "EARPIECE", NULL, "Earpiece Amp" },
 };
 
+static int sun50i_a64_codec_probe(struct snd_soc_component *component)
+{
+	struct sun50i_codec_analog *codec = snd_soc_component_get_drvdata(component);
+
+	regmap_update_bits(component->regmap, SUN50I_ADDA_JACK_MIC_CTRL,
+			   BIT(SUN50I_ADDA_JACK_MIC_CTRL_INNERRESEN),
+			   codec->internal_bias_resistor <<
+				SUN50I_ADDA_JACK_MIC_CTRL_INNERRESEN);
+
+	return 0;
+}
+
 static int sun50i_a64_codec_suspend(struct snd_soc_component *component)
 {
 	return regmap_update_bits(component->regmap, SUN50I_ADDA_HP_CTRL,
@@ -491,6 +508,7 @@ static const struct snd_soc_component_driver sun50i_codec_analog_cmpnt_drv = {
 	.num_dapm_widgets	= ARRAY_SIZE(sun50i_a64_codec_widgets),
 	.dapm_routes		= sun50i_a64_codec_routes,
 	.num_dapm_routes	= ARRAY_SIZE(sun50i_a64_codec_routes),
+	.probe			= sun50i_a64_codec_probe,
 	.suspend		= sun50i_a64_codec_suspend,
 	.resume			= sun50i_a64_codec_resume,
 };
@@ -505,9 +523,20 @@ MODULE_DEVICE_TABLE(of, sun50i_codec_analog_of_match);
 
 static int sun50i_codec_analog_probe(struct platform_device *pdev)
 {
+	struct sun50i_codec_analog *codec;
 	struct regmap *regmap;
 	void __iomem *base;
 
+	codec = devm_kzalloc(&pdev->dev, sizeof(*codec), GFP_KERNEL);
+	if (!codec)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, codec);
+
+	codec->internal_bias_resistor =
+		device_property_read_bool(&pdev->dev,
+					  "allwinner,internal-bias-resistor");
+
 	base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(base)) {
 		dev_err(&pdev->dev, "Failed to map the registers\n");
-- 
2.35.1