Re: [PATCH v3 1/5] drivers: provide devm_platform_get_and_ioremap_resource()

[Greg KH <gregkh@linuxfoundation.org>]

On Sun, Mar 15, 2020 at 10:05:21PM +0800, Dejin Zheng wrote:
> Since commit "drivers: provide devm_platform_ioremap_resource()",
> it was wrap platform_get_resource() and devm_ioremap_resource() as
> single helper devm_platform_ioremap_resource(). but now, many drivers
> still used platform_get_resource() and devm_ioremap_resource()
> together in the kernel tree. The reason can not be replaced is they
> still need use the resource variables obtained by platform_get_resource().
> so provide this helper.
> 
> Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
> Suggested-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
> Signed-off-by: Dejin Zheng <zhengdejin5@gmail.com>
> ---
> v2 -> v3:
> 	- rename the function to
> 	  devm_platform_get_and_ioremap_resource() by Sergei's suggestion.
> 	- make the last parameter res as optional by Geert's suggestion.
> 
> v1 -> v2:
> 	- No change.
> 
>  drivers/base/platform.c         | 22 ++++++++++++++++++++++
>  include/linux/platform_device.h |  3 +++
>  2 files changed, 25 insertions(+)
> 
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index 7fa654f1288b..9f6a78f79235 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -62,6 +62,28 @@ struct resource *platform_get_resource(struct platform_device *dev,
>  EXPORT_SYMBOL_GPL(platform_get_resource);
>  
>  #ifdef CONFIG_HAS_IOMEM
> +/**
> + * devm_platform_get_and_ioremap_resource - call devm_ioremap_resource() for a
> + *					    platform device and get resource
> + *
> + * @pdev: platform device to use both for memory resource lookup as well as
> + *        resource management
> + * @index: resource index
> + * @res: get the resource
> + */
> +void __iomem *
> +devm_platform_get_and_ioremap_resource(struct platform_device *pdev,
> +				unsigned int index, struct resource **res)
> +{
> +	struct resource *r;
> +
> +	r = platform_get_resource(pdev, IORESOURCE_MEM, index);
> +	if (res)
> +		*res = r;

What happens if that call fails?  Shouldn't that be checked?

thanks,

greg k-h