There is a power saving mechanism in rt5640. It will turn off some
unused power when MCLK is not present. We call that "MCLK detection"
and it should be enabled by default.
Signed-off-by: Bard Liao <bardliao@realtek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
        if (ret != 0)
                dev_warn(&i2c->dev, "Failed to apply regmap patch: %d\n", ret);
 
+       regmap_update_bits(rt5640->regmap, RT5640_DUMMY1,
+                               RT5640_MCLK_DET, RT5640_MCLK_DET);
+
        if (rt5640->pdata.in1_diff)
                regmap_update_bits(rt5640->regmap, RT5640_IN1_IN2,
                                        RT5640_IN_DF1, RT5640_IN_DF1);
 
 #define RT5640_ZCD_HP_DIS                      (0x0 << 15)
 #define RT5640_ZCD_HP_EN                       (0x1 << 15)
 
+/* General Control 1 (0xfa) */
+#define RT5640_MCLK_DET                                (0x1 << 11)
 
 /* Codec Private Register definition */
 /* 3D Speaker Control (0x63) */