[PATCH V3] ASoC: cs42xx8: Add reset gpio handling

[S.j. Wang]

Handle the reset GPIO and reset the device every time we
start it.

Signed-off-by: Shengjiu Wang <shengjiu.w...@nxp.com>
---
Changes in v3
- update binding document.

Changes in v2
- use devm_gpiod_get_optional instead of of_get_named_gpio

 Documentation/devicetree/bindings/sound/cs42xx8.txt |  6 ++++++
 sound/soc/codecs/cs42xx8.c                          | 13 +++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/Documentation/devicetree/bindings/sound/cs42xx8.txt 
b/Documentation/devicetree/bindings/sound/cs42xx8.txt
index 8619a156d038..ab8f54095269 100644
--- a/Documentation/devicetree/bindings/sound/cs42xx8.txt
+++ b/Documentation/devicetree/bindings/sound/cs42xx8.txt
@@ -14,6 +14,11 @@ Required properties:
   - VA-supply, VD-supply, VLS-supply, VLC-supply: power supplies for the 
device,
     as covered in Documentation/devicetree/bindings/regulator/regulator.txt
 
+Optional properties:
+
+  - reset-gpio : a GPIO spec to define which pin is connected to the chip's
+    !RESET pin
+
 Example:
 
 cs42888: codec@48 {
@@ -25,4 +30,5 @@ cs42888: codec@48 {
        VD-supply = <&reg_audio>;
        VLS-supply = <&reg_audio>;
        VLC-supply = <&reg_audio>;
+       reset-gpio = <&pca9557_b 1 1>;
 };
diff --git a/sound/soc/codecs/cs42xx8.c b/sound/soc/codecs/cs42xx8.c
index 28a4ac36c4f8..b377cddaf2e6 100644
--- a/sound/soc/codecs/cs42xx8.c
+++ b/sound/soc/codecs/cs42xx8.c
@@ -14,6 +14,7 @@
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
+#include <linux/of_gpio.h>
 #include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
 #include <sound/pcm_params.h>
@@ -45,6 +46,7 @@ struct cs42xx8_priv {
        bool slave_mode;
        unsigned long sysclk;
        u32 tx_channels;
+       struct gpio_desc *gpiod_reset;
 };
 
 /* -127.5dB to 0dB with step of 0.5dB */
@@ -467,6 +469,13 @@ int cs42xx8_probe(struct device *dev, struct regmap 
*regmap)
                return -EINVAL;
        }
 
+       cs42xx8->gpiod_reset = devm_gpiod_get_optional(dev, "reset",
+                                                       GPIOD_OUT_HIGH);
+       if (IS_ERR(cs42xx8->gpiod_reset))
+               return PTR_ERR(cs42xx8->gpiod_reset);
+
+       gpiod_set_value_cansleep(cs42xx8->gpiod_reset, 0);
+
        cs42xx8->clk = devm_clk_get(dev, "mclk");
        if (IS_ERR(cs42xx8->clk)) {
                dev_err(dev, "failed to get the clock: %ld\n",
@@ -547,6 +556,8 @@ static int cs42xx8_runtime_resume(struct device *dev)
                return ret;
        }
 
+       gpiod_set_value_cansleep(cs42xx8->gpiod_reset, 0);
+
        ret = regulator_bulk_enable(ARRAY_SIZE(cs42xx8->supplies),
                                    cs42xx8->supplies);
        if (ret) {
@@ -586,6 +597,8 @@ static int cs42xx8_runtime_suspend(struct device *dev)
        regulator_bulk_disable(ARRAY_SIZE(cs42xx8->supplies),
                               cs42xx8->supplies);
 
+       gpiod_set_value_cansleep(cs42xx8->gpiod_reset, 1);
+
        clk_disable_unprepare(cs42xx8->clk);
 
        return 0;
-- 
2.21.0