linux-kernel - [RFC PATCH] net: macb: Add null check for PCLK and HCLK

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Date:   Tue, 19 Mar 2019 11:24:05 +0530
From:   Harini Katakam <harini.katakam@...inx.com>
To:     <nicolas.ferre@...rochip.com>, <davem@...emloft.net>
CC:     <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <michal.simek@...inx.com>, <harinikatakamlinux@...il.com>,
        <harini.katakam@...inx.com>
Subject: [RFC PATCH] net: macb: Add null check for PCLK and HCLK

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@...inx.com>
---
 drivers/net/ethernet/cadence/macb_main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index ad099fd..d12d815 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -3370,13 +3370,13 @@ 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(*pclk) || (*pclk == NULL)) {
 		err = PTR_ERR(*pclk);
 		dev_err(&pdev->dev, "failed to get macb_clk (%u)\n", err);
 		return err;
 	}
 
-	if (IS_ERR(*hclk)) {
+	if (IS_ERR(*hclk) || (*hclk == NULL)) {
 		err = PTR_ERR(*hclk);
 		dev_err(&pdev->dev, "failed to get hclk (%u)\n", err);
 		return err;
-- 
2.7.4