ASoC: sgtl5000: Add MicBias resistor support in DT

Some systems may require a different resistor than the default one (4K).
This adds a property in sgtl5000 codec.
It keeps the default of 4K when nothing is specified so it does not break
existing code.

Signed-off-by: Jean-Michel Hautbois <jean-michel.hautbois@vodalys.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 51 insertions, 4 deletions

diff --git a/sound/soc/codecs/sgtl5000.c b/sound/soc/codecs/sgtl5000.c
index 10160e7a9277..c417b4ad0492 100644
--- a/sound/soc/codecs/sgtl5000.c
+++ b/sound/soc/codecs/sgtl5000.c
@@ -16,6 +16,7 @@
 #include <linux/pm.h>
 #include <linux/i2c.h>
 #include <linux/clk.h>
+#include <linux/log2.h>
 #include <linux/regmap.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
@@ -121,6 +122,13 @@ struct ldo_regulator {
         bool enabled;
 };
 
+enum sgtl5000_micbias_resistor {
+        SGTL5000_MICBIAS_OFF = 0,
+        SGTL5000_MICBIAS_2K = 2,
+        SGTL5000_MICBIAS_4K = 4,
+        SGTL5000_MICBIAS_8K = 8,
+};
+
 /* sgtl5000 private structure in codec */
 struct sgtl5000_priv {
         int sysclk;     /* sysclk rate */
@@ -131,6 +139,7 @@ struct sgtl5000_priv {
         struct regmap *regmap;
         struct clk *mclk;
         int revision;
+        u8 micbias_resistor;
 };
 
 /*
@@ -145,12 +154,14 @@ struct sgtl5000_priv {
 static int mic_bias_event(struct snd_soc_dapm_widget *w,
         struct snd_kcontrol *kcontrol, int event)
 {
+        struct sgtl5000_priv *sgtl5000 = snd_soc_codec_get_drvdata(w->codec);
+
         switch (event) {
         case SND_SOC_DAPM_POST_PMU:
-                /* change mic bias resistor to 4Kohm */
+                /* change mic bias resistor */
                 snd_soc_update_bits(w->codec, SGTL5000_CHIP_MIC_CTRL,
-                                SGTL5000_BIAS_R_MASK,
-                                SGTL5000_BIAS_R_4k << SGTL5000_BIAS_R_SHIFT);
+                        SGTL5000_BIAS_R_MASK,
+                        sgtl5000->micbias_resistor << SGTL5000_BIAS_R_SHIFT);
                 break;
 
         case SND_SOC_DAPM_PRE_PMD:
@@ -1327,7 +1338,9 @@ static int sgtl5000_probe(struct snd_soc_codec *codec)
                         SGTL5000_HP_ZCD_EN |
                         SGTL5000_ADC_ZCD_EN);
 
-        snd_soc_write(codec, SGTL5000_CHIP_MIC_CTRL, 2);
+        snd_soc_update_bits(codec, SGTL5000_CHIP_MIC_CTRL,
+                        SGTL5000_BIAS_R_MASK,
+                        sgtl5000->micbias_resistor << SGTL5000_BIAS_R_SHIFT);
 
         /*
          * disable DAP
@@ -1419,6 +1432,8 @@ static int sgtl5000_i2c_probe(struct i2c_client *client,
         struct sgtl5000_priv *sgtl5000;
         int ret, reg, rev;
         unsigned int mclk;
+        struct device_node *np = client->dev.of_node;
+        u32 value;
 
         sgtl5000 = devm_kzalloc(&client->dev, sizeof(struct sgtl5000_priv),
                                                                 GFP_KERNEL);
@@ -1471,6 +1486,38 @@ static int sgtl5000_i2c_probe(struct i2c_client *client,
         dev_info(&client->dev, "sgtl5000 revision 0x%x\n", rev);
         sgtl5000->revision = rev;
 
+        if (np) {
+                if (!of_property_read_u32(np,
+                        "micbias-resistor-k-ohms", &value)) {
+                        switch (value) {
+                        case SGTL5000_MICBIAS_OFF:
+                                sgtl5000->micbias_resistor = 0;
+                                break;
+                        case SGTL5000_MICBIAS_2K:
+                                sgtl5000->micbias_resistor = 1;
+                                break;
+                        case SGTL5000_MICBIAS_4K:
+                                sgtl5000->micbias_resistor = 2;
+                                break;
+                        case SGTL5000_MICBIAS_8K:
+                                sgtl5000->micbias_resistor = 3;
+                                break;
+                        default:
+                                sgtl5000->micbias_resistor = 2;
+                                dev_err(&client->dev,
+                                        "Unsuitable MicBias resistor\n");
+                        }
+                } else {
+                        /* default is 4Kohms */
+                        sgtl5000->micbias_resistor = 2;
+                }
+                                dev_err(&client->dev,
+                                        "Unsuitable MicBias resistor\n");
+                        }
+                } else {
+                }
+        }
+
         i2c_set_clientdata(client, sgtl5000);
 
         /* Ensure sgtl5000 will start with sane register values */