[PATCH] pinctrl: fix Null pointer dereference

[clingfei]

pinmux_generic_get_function may returns NULL, and its retval is
dereferenced without check, which will cause a null pointer dereference.

Signed-off-by: clingfei <clf700383 at gmail.com>
---
 drivers/pinctrl/pinctrl-th1520.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/pinctrl/pinctrl-th1520.c b/drivers/pinctrl/pinctrl-th1520.c
index 1bb78b212fd5..9331f4462480 100644
--- a/drivers/pinctrl/pinctrl-th1520.c
+++ b/drivers/pinctrl/pinctrl-th1520.c
@@ -798,6 +798,8 @@ static int th1520_pinmux_set_mux(struct pinctrl_dev *pctldev,
 	struct th1520_pinctrl *thp = pinctrl_dev_get_drvdata(pctldev);
 	const struct function_desc *func = pinmux_generic_get_function(pctldev, fsel);
 
+	if (!func)
+		return -EINVAL;
 	return th1520_pinmux_set(thp, thp->desc.pins[gsel].number,
 				 (uintptr_t)thp->desc.pins[gsel].drv_data & TH1520_PAD_MUXDATA,
 				 (uintptr_t)func->data);
-- 
2.34.1