linux-kernel - [PATCH v2 2/3] ASoC: sun50i-codec-analog: Add support for internal bias

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Date:   Mon, 20 Jun 2022 22:54:51 -0500
From:   Samuel Holland <samuel@...lland.org>
To:     Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     Arnaud Ferraris <arnaud.ferraris@...labora.com>,
        Samuel Holland <samuel@...lland.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Maxime Ripard <mripard@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Takashi Iwai <tiwai@...e.com>, alsa-devel@...a-project.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, linux-sunxi@...ts.linux.dev
Subject: [PATCH v2 2/3] ASoC: sun50i-codec-analog: Add support for internal bias

From: Arnaud Ferraris <arnaud.ferraris@...labora.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@...labora.com>
[Samuel: split binding and implementation; move to device probe]
Signed-off-by: Samuel Holland <samuel@...lland.org>
---

Changes in v2:
 - Move register update from component probe to device probe

 sound/soc/sunxi/sun50i-codec-analog.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/sound/soc/sunxi/sun50i-codec-analog.c b/sound/soc/sunxi/sun50i-codec-analog.c
index a41e25ad0aaf..e1e5e8de0130 100644
--- a/sound/soc/sunxi/sun50i-codec-analog.c
+++ b/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);
-- 
2.35.1