[PATCH v2] ASoC: aw88395: Fix kernel panic caused by invalid GPIO error pointer

[wangdich9700]

From: wangdicheng <wangdicheng@xxxxxxxxxx>

In aw88395_i2c_probe(), if `devm_gpiod_get_optional()` fails, it returns
an ERR_PTR() error pointer. The current code only prints a message and
continues execution, leaving `aw88395->reset_gpio` as an invalid pointer.

Later, in `aw88395_hw_reset()`, this invalid pointer is passed to
`gpiod_set_value_cansleep()`, which dereferences it and causes a kernel
panic.

For optional GPIOs, `devm_gpiod_get_optional()` returns NULL if the GPIO
is not defined in the DT, which is safe. If it returns an ERR_PTR, it
means a real error occurred (e.g., -EPROBE_DEFER) and the probe must be
aborted.

Also, since the GPIO is optional, remove the dev_err() log in
aw88395_hw_reset() when the GPIO is missing to match the optional
semantics. This also fixes a potential NULL pointer dereference as
aw_pa is not initialized when aw88395_hw_reset() is called.

Signed-off-by: wangdicheng <wangdicheng@xxxxxxxxxx>
---
v1->v2:
Remove dev_err() in aw88395_hw_reset() to align with optional GPIO
semantics and fix NULL pointer dereference if aw_pa is uninitialized.

 sound/soc/codecs/aw88395/aw88395.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/sound/soc/codecs/aw88395/aw88395.c b/sound/soc/codecs/aw88395/aw88395.c
index 3602b5b9f7d7..dd09bac652f7 100644
--- a/sound/soc/codecs/aw88395/aw88395.c
+++ b/sound/soc/codecs/aw88395/aw88395.c
@@ -456,8 +456,6 @@ static void aw88395_hw_reset(struct aw88395 *aw88395)
 		usleep_range(AW88395_1000_US, AW88395_1000_US + 10);
 		gpiod_set_value_cansleep(aw88395->reset_gpio, 1);
 		usleep_range(AW88395_1000_US, AW88395_1000_US + 10);
-	} else {
-		dev_err(aw88395->aw_pa->dev, "%s failed", __func__);
 	}
 }
 
@@ -522,9 +520,10 @@ static int aw88395_i2c_probe(struct i2c_client *i2c)
 	i2c_set_clientdata(i2c, aw88395);
 
 	aw88395->reset_gpio = devm_gpiod_get_optional(&i2c->dev, "reset", GPIOD_OUT_LOW);
-	if (IS_ERR(aw88395->reset_gpio))
-		dev_info(&i2c->dev, "reset gpio not defined\n");
-
+	if (IS_ERR(aw88395->reset_gpio)) {
+		return dev_err_probe(&i2c->dev, PTR_ERR(aw88395->reset_gpio),
+				"failed to get reset gpio\n");
+	}
 	/* hardware reset */
 	aw88395_hw_reset(aw88395);
 
-- 
2.25.1