1 files changed, 44 insertions, 4 deletions

diff --git a/sound/soc/codecs/pcm3168a.c b/sound/soc/codecs/pcm3168a.c
index 313500ab36df..9711fab296eb 100644
--- a/sound/soc/codecs/pcm3168a.c
+++ b/sound/soc/codecs/pcm3168a.c
@@ -9,7 +9,9 @@
 
 #include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/gpio/consumer.h>
 #include <linux/module.h>
+#include <linux/of_gpio.h>
 #include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
 
@@ -59,6 +61,7 @@ struct pcm3168a_priv {
 	struct regulator_bulk_data supplies[PCM3168A_NUM_SUPPLIES];
 	struct regmap *regmap;
 	struct clk *scki;
+	struct gpio_desc *gpio_rst;
 	unsigned long sysclk;
 
 	struct pcm3168a_io_params io_params[2];
@@ -643,6 +646,7 @@ static bool pcm3168a_readable_register(struct device *dev, unsigned int reg)
 static bool pcm3168a_volatile_register(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
+	case PCM3168A_RST_SMODE:
 	case PCM3168A_DAC_ZERO:
 	case PCM3168A_ADC_OV:
 		return true;
@@ -702,6 +706,25 @@ int pcm3168a_probe(struct device *dev, struct regmap *regmap)
 
 	dev_set_drvdata(dev, pcm3168a);
 
+	/*
+	 * Request the reset (connected to RST pin) gpio line as non exclusive
+	 * as the same reset line might be connected to multiple pcm3168a codec
+	 *
+	 * The RST is low active, we want the GPIO line to be high initially, so
+	 * request the initial level to LOW which in practice means DEASSERTED:
+	 * The deasserted level of GPIO_ACTIVE_LOW is HIGH.
+	 */
+	pcm3168a->gpio_rst = devm_gpiod_get_optional(dev, "reset",
+						GPIOD_OUT_LOW |
+						GPIOD_FLAGS_BIT_NONEXCLUSIVE);
+	if (IS_ERR(pcm3168a->gpio_rst)) {
+		ret = PTR_ERR(pcm3168a->gpio_rst);
+		if (ret != -EPROBE_DEFER )
+			dev_err(dev, "failed to acquire RST gpio: %d\n", ret);
+
+		return ret;
+	}
+
 	pcm3168a->scki = devm_clk_get(dev, "scki");
 	if (IS_ERR(pcm3168a->scki)) {
 		ret = PTR_ERR(pcm3168a->scki);
@@ -743,10 +766,18 @@ int pcm3168a_probe(struct device *dev, struct regmap *regmap)
 		goto err_regulator;
 	}
 
-	ret = pcm3168a_reset(pcm3168a);
-	if (ret) {
-		dev_err(dev, "Failed to reset device: %d\n", ret);
-		goto err_regulator;
+	if (pcm3168a->gpio_rst) {
+		/*
+		 * The device is taken out from reset via GPIO line, wait for
+		 * 3846 SCKI clock cycles for the internal reset de-assertion
+		 */
+		msleep(DIV_ROUND_UP(3846 * 1000, pcm3168a->sysclk));
+	} else {
+		ret = pcm3168a_reset(pcm3168a);
+		if (ret) {
+			dev_err(dev, "Failed to reset device: %d\n", ret);
+			goto err_regulator;
+		}
 	}
 
 	pm_runtime_set_active(dev);
@@ -785,6 +816,15 @@ static void pcm3168a_disable(struct device *dev)
 
 void pcm3168a_remove(struct device *dev)
 {
+	struct pcm3168a_priv *pcm3168a = dev_get_drvdata(dev);
+
+	/*
+	 * The RST is low active, we want the GPIO line to be low when the
+	 * driver is removed, so set level to 1 which in practice means
+	 * ASSERTED:
+	 * The asserted level of GPIO_ACTIVE_LOW is LOW.
+	 */
+	gpiod_set_value_cansleep(pcm3168a->gpio_rst, 1);
 	pm_runtime_disable(dev);
 #ifndef CONFIG_PM
 	pcm3168a_disable(dev);