net: macb: Add null check for PCLK and HCLK

[ Upstream commit cd5afa91f078c0787be0a62b5ef90301c00b0271 ]

Both PCLK and HCLK are "required" clocks according to macb devicetree
documentation. There is a chance that devm_clk_get doesn't return a
negative error but just a NULL clock structure instead. In such a case
the driver proceeds as usual and uses pclk value 0 to calculate MDC
divisor which is incorrect. Hence fix the same in clock initialization.

Signed-off-by: Harini Katakam <harini.katakam@xilinx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org>

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 8abea1c..7d7b513 100644 (file)
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -3323,14 +3323,20 @@ static int macb_clk_init(struct platform_device *pdev, struct clk **pclk,
                *hclk = devm_clk_get(&pdev->dev, "hclk");
        }
 
-       if (IS_ERR(*pclk)) {
+       if (IS_ERR_OR_NULL(*pclk)) {
                err = PTR_ERR(*pclk);
+               if (!err)
+                       err = -ENODEV;
+
                dev_err(&pdev->dev, "failed to get macb_clk (%u)\n", err);
                return err;
        }
 
-       if (IS_ERR(*hclk)) {
+       if (IS_ERR_OR_NULL(*hclk)) {
                err = PTR_ERR(*hclk);
+               if (!err)
+                       err = -ENODEV;
+
                dev_err(&pdev->dev, "failed to get hclk (%u)\n", err);
                return err;
        }