[PATCH v2 2/3] serial: mtk: guard clk ops on clk.dev

From: Suhrid Subramaniam <[email protected]>

Check that priv->clk has been populated before trying to use it in the
MediaTek serial driver.

The clock is optional and may not be populated in all cases (in which
case it is expected that there was a fixed clock rate provided.)

Fixes: 3b17f2e2c2a9 ("serial: mtk: add support for using dynamic baud clock souce")
Signed-off-by: Suhrid Subramaniam <[email protected]>
Signed-off-by: David Lechner <[email protected]>
---
 drivers/serial/serial_mtk.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/serial/serial_mtk.c b/drivers/serial/serial_mtk.c
index 28e87f485a2..fff2f639cf6 100644
--- a/drivers/serial/serial_mtk.c
+++ b/drivers/serial/serial_mtk.c
@@ -215,9 +215,13 @@ static int mtk_serial_setbrg(struct udevice *dev, int baudrate)
 	struct mtk_serial_priv *priv = dev_get_priv(dev);
 	ulong clk_rate;
 
-	clk_rate = clk_get_rate(&priv->clk);
-	if (IS_ERR_VALUE(clk_rate) || clk_rate == 0)
+	if (priv->clk.dev) {
+		clk_rate = clk_get_rate(&priv->clk);
+		if (IS_ERR_VALUE(clk_rate) || clk_rate == 0)
+			return -EINVAL;
+	} else {
 		clk_rate = priv->fixed_clk_rate;
+	}
 
 	_mtk_serial_setbrg(priv, baudrate, clk_rate);
 
@@ -255,7 +259,8 @@ static int mtk_serial_probe(struct udevice *dev)
 	writel(UART_MCRVAL, &priv->regs->mcr);
 	writel(UART_FCRVAL, &priv->regs->fcr);
 
-	clk_enable(&priv->clk);
+	if (priv->clk.dev)
+		clk_enable(&priv->clk);
 	if (priv->clk_bus.dev)
 		clk_enable(&priv->clk_bus);
 

-- 
2.43.0