[PATCH -next v3] serial: 8250_bcm2835aux: Add missing clk_disable_unprepare()

[Guo Mengqi]

The error path when get clock frequency fails in bcm2835aux_serial
driver does not correctly disable the clock.

This flaw was found using a static analysis tool "Hulk Robot", which
reported the following warning when analyzing linux-next/master:

    drivers/tty/serial/8250/8250_bcm2835aux.c:
    warning: clk_disable_unprepare_missing.cocci

The cocci script checks for the existence of clk_disable_unprepare()
paired with clk_prepare_enable().

Add the missing clk_disable_unprepare() to the error path.

Fixes: fcc446c8aa63 ("serial: 8250_bcm2835aux: Add ACPI support")
Reported-by: Hulk Robot <hulkci at huawei.com>
Signed-off-by: Guo Mengqi <guomengqi3 at huawei.com>
---
v2:
- Change title to more standard format
- Add details about how Hulk Robot report this issue.
v3:
- add which commit this patch fixes
---
 drivers/tty/serial/8250/8250_bcm2835aux.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_bcm2835aux.c b/drivers/tty/serial/8250/8250_bcm2835aux.c
index 047e14ccb165..15a2387a5b25 100644
--- a/drivers/tty/serial/8250/8250_bcm2835aux.c
+++ b/drivers/tty/serial/8250/8250_bcm2835aux.c
@@ -167,8 +167,10 @@ static int bcm2835aux_serial_probe(struct platform_device *pdev)
 	uartclk = clk_get_rate(data->clk);
 	if (!uartclk) {
 		ret = device_property_read_u32(&pdev->dev, "clock-frequency", &uartclk);
-		if (ret)
-			return dev_err_probe(&pdev->dev, ret, "could not get clk rate\n");
+		if (ret) {
+			dev_err_probe(&pdev->dev, ret, "could not get clk rate\n");
+			goto dis_clk;
+		}
 	}
 
 	/* the HW-clock divider for bcm2835aux is 8,
-- 
2.17.1