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

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

[Harini Katakam]

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>
---
 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

Re: [RFC PATCH] net: macb: Add null check for PCLK and HCLK

[Claudiu.Beznea]

On 19.03.2019 07:54, Harini Katakam wrote:
> 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>
> ---
>  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)) {

You can use IS_ERR_OR_NULL() macro.

>  		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)) {

Ditto

>  		err = PTR_ERR(*hclk);
>  		dev_err(&pdev->dev, "failed to get hclk (%u)\n", err);
>  		return err;
> 

Re: [RFC PATCH] net: macb: Add null check for PCLK and HCLK

[Harini Katakam]

Hi Claudiu,

On Tue, Mar 19, 2019 at 9:51 PM <Claudiu.Beznea@microchip.com> wrote:
>
>
>
> On 19.03.2019 07:54, Harini Katakam wrote:
<snip>
> > -     if (IS_ERR(*pclk)) {
> > +     if (IS_ERR(*pclk) || (*pclk == NULL)) {
>
> You can use IS_ERR_OR_NULL() macro.
>
Yes will fix, thanks.
Also the error code from this function will end up being 0 below
even if pointer is NULL. Will fix that.

Regards,
Harini

> >               err = PTR_ERR(*pclk);
> >               dev_err(&pdev->dev, "failed to get macb_clk (%u)\n", err);
> >               return err;
> >       }