Re: [PATCH v3 1/3] drm/panel: Fix IS_ERR() vs NULL check in nt35950_probe()

[Sam Ravnborg <sam@ravnborg.org>]

Hi Gaosheng,
On Fri, Jul 14, 2023 at 09:48:18AM +0800, Gaosheng Cui wrote:
> The mipi_dsi_device_register_full() returns an ERR_PTR() on failure,
> we should use IS_ERR() to check the return value.

Correct - so the code is indeed wrong.

Can you update it so we print the error code as this can be very
helpful.

And then please use dev_probe_err() too.

	Sam

> 
> Fixes: 623a3531e9cf ("drm/panel: Add driver for Novatek NT35950 DSI DriverIC panels")
> Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
> ---
>  drivers/gpu/drm/panel/panel-novatek-nt35950.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/panel/panel-novatek-nt35950.c b/drivers/gpu/drm/panel/panel-novatek-nt35950.c
> index 8b108ac80b55..4903bbf1df55 100644
> --- a/drivers/gpu/drm/panel/panel-novatek-nt35950.c
> +++ b/drivers/gpu/drm/panel/panel-novatek-nt35950.c
> @@ -571,7 +571,7 @@ static int nt35950_probe(struct mipi_dsi_device *dsi)
>  		}
>  
>  		nt->dsi[1] = mipi_dsi_device_register_full(dsi_r_host, info);
> -		if (!nt->dsi[1]) {
> +		if (IS_ERR(nt->dsi[1])) {
>  			dev_err(dev, "Cannot get secondary DSI node\n");
>  			return -ENODEV;
>  		}
> -- 
> 2.25.1