ASoC: wm8804: Add support for hardware reset line

It is best to use the physical reset if it is available. This patch adds
support for a GPIO controlled physical reset for the chip.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 21 insertions, 5 deletions

diff --git a/sound/soc/codecs/wm8804.c b/sound/soc/codecs/wm8804.c
index f44da83f50dc..cc168c4a4be0 100644
--- a/sound/soc/codecs/wm8804.c
+++ b/sound/soc/codecs/wm8804.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/init.h>
+#include <linux/gpio/consumer.h>
 #include <linux/delay.h>
 #include <linux/pm.h>
 #include <linux/of_device.h>
@@ -61,6 +62,8 @@ struct wm8804_priv {
         struct regulator_bulk_data supplies[WM8804_NUM_SUPPLIES];
         struct notifier_block disable_nb[WM8804_NUM_SUPPLIES];
         int mclk_div;
+
+        struct gpio_desc *reset;
 };
 
 static int txsrc_get(struct snd_kcontrol *kcontrol,
@@ -182,7 +185,7 @@ static bool wm8804_volatile(struct device *dev, unsigned int reg)
         }
 }
 
-static int wm8804_reset(struct wm8804_priv *wm8804)
+static int wm8804_soft_reset(struct wm8804_priv *wm8804)
 {
         return regmap_write(wm8804->regmap, WM8804_RST_DEVID1, 0x0);
 }
@@ -586,6 +589,14 @@ int wm8804_probe(struct device *dev, struct regmap *regmap)
 
         wm8804->regmap = regmap;
 
+        wm8804->reset = devm_gpiod_get_optional(dev, "wlf,reset",
+                                                GPIOD_OUT_LOW);
+        if (IS_ERR(wm8804->reset)) {
+                ret = PTR_ERR(wm8804->reset);
+                dev_err(dev, "Failed to get reset line: %d\n", ret);
+                return ret;
+        }
+
         for (i = 0; i < ARRAY_SIZE(wm8804->supplies); i++)
                 wm8804->supplies[i].supply = wm8804_supply_names[i];
 
@@ -620,6 +631,9 @@ int wm8804_probe(struct device *dev, struct regmap *regmap)
                 return ret;
         }
 
+        if (wm8804->reset)
+                gpiod_set_value_cansleep(wm8804->reset, 1);
+
         ret = regmap_read(regmap, WM8804_RST_DEVID1, &id1);
         if (ret < 0) {
                 dev_err(dev, "Failed to read device ID: %d\n", ret);
@@ -648,10 +662,12 @@ int wm8804_probe(struct device *dev, struct regmap *regmap)
         }
         dev_info(dev, "revision %c\n", id1 + 'A');
 
-        ret = wm8804_reset(wm8804);
-        if (ret < 0) {
-                dev_err(dev, "Failed to issue reset: %d\n", ret);
-                goto err_reg_enable;
+        if (!wm8804->reset) {
+                ret = wm8804_soft_reset(wm8804);
+                if (ret < 0) {
+                        dev_err(dev, "Failed to issue reset: %d\n", ret);
+                        goto err_reg_enable;
+                }
         }
 
         ret = snd_soc_register_codec(dev, &soc_codec_dev_wm8804,