[PATCH] drm: rcar-du: Fix the return check of of_parse_phandle and of_find_device_by_node

[Kieran Bingham]

Hi Wang Xiaojun,

On 11/11/2020 03:14, Wang Xiaojun wrote:
> of_parse_phandle and of_find_device_by_node may return NULL
> which cannot be checked by IS_ERR.

Indeed, both of these functions return either NULL or the correct value,
and no an errno.

> 
> Signed-off-by: Wang Xiaojun <wangxiaojun11 at huawei.com>
> Reported-by: Hulk Robot <hulkci at huawei.com>

Fixes: 8de707aeb452 ("drm: rcar-du: kms: Initialize CMM instances")

Reviewed-by: Kieran Bingham <kieran.bingham+renesas at ideasonboard.com>

> ---
>  drivers/gpu/drm/rcar-du/rcar_du_kms.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_kms.c b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
> index 72dda446355f..fcfddf7ad3f3 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
> @@ -700,10 +700,10 @@ static int rcar_du_cmm_init(struct rcar_du_device *rcdu)
>  		int ret;
>  
>  		cmm = of_parse_phandle(np, "renesas,cmms", i);
> -		if (IS_ERR(cmm)) {
> +		if (!cmm) {
>  			dev_err(rcdu->dev,
>  				"Failed to parse 'renesas,cmms' property\n");
> -			return PTR_ERR(cmm);
> +			return -ENODEV;
>  		}
>  
>  		if (!of_device_is_available(cmm)) {
> @@ -713,10 +713,10 @@ static int rcar_du_cmm_init(struct rcar_du_device *rcdu)
>  		}
>  
>  		pdev = of_find_device_by_node(cmm);
> -		if (IS_ERR(pdev)) {
> +		if (!pdev) {
>  			dev_err(rcdu->dev, "No device found for CMM%u\n", i);
>  			of_node_put(cmm);
> -			return PTR_ERR(pdev);
> +			return -ENODEV;
>  		}
>  
>  		of_node_put(cmm);
>