ASoC: sun50i-codec-analog: Add support for internal bias

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@collabora.com>
[Samuel: split binding and implementation; move to device probe]
Signed-off-by: Samuel Holland <samuel@sholland.org>
Link: https://lore.kernel.org/r/20220621035452.60272-3-samuel@sholland.orgSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sunxi/sun50i-codec-analog.c

@@ -117,6 +117,7 @@
 #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
 
 /* mixer controls */
@@ -507,6 +508,7 @@ static int sun50i_codec_analog_probe(struct platform_device *pdev)
 {
 	struct regmap *regmap;
 	void __iomem *base;
+	bool enable;
 
 	base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(base)) {
@@ -520,6 +522,12 @@ static int sun50i_codec_analog_probe(struct platform_device *pdev)
 		return PTR_ERR(regmap);
 	}
 
+	enable = device_property_read_bool(&pdev->dev,
+					   "allwinner,internal-bias-resistor");
+	regmap_update_bits(regmap, SUN50I_ADDA_JACK_MIC_CTRL,
+			   BIT(SUN50I_ADDA_JACK_MIC_CTRL_INNERRESEN),
+			   enable << SUN50I_ADDA_JACK_MIC_CTRL_INNERRESEN);
+
 	return devm_snd_soc_register_component(&pdev->dev,
 					       &sun50i_codec_analog_cmpnt_drv,
 					       NULL, 0);