Re: [PATCH v2 1/2] ARM: OMAP2+: only search for GPMC DT child nodes on probe

[Jon Hunter <jon-hunter@ti.com>]

On 04/17/2013 03:34 PM, Javier Martinez Canillas wrote:
> The GPMC DT probe function use for_each_node_by_name() to search
> child device nodes of the GPMC controller. But this function does
> not use the GPMC device node as the root of the search and instead
> search across the complete Device Tree.
> 
> This means that any device node on the DT that is using any of the
> GPMC child nodes names searched for will be returned even if they
> are not connected to the GPMC, making the gpmc_probe_xxx_child()
> function to fail.
> 
> Fix this by using the GPMC device node as the search root so the
> search will be restricted to its children.
> 
> Reported-by: Lars Poeschel <poeschel@lemonage.de>
> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
> ---
> 
> Changes since v1 (suggested by Jon Hunter):
>   - Split the search for GPMC child nodes and only warn if a
>     child probe fails on two different patches
>   - Don't probe all childs unnecesary if a previous matched
> 
>  arch/arm/mach-omap2/gpmc.c |   33 ++++++++++-----------------------
>  1 files changed, 10 insertions(+), 23 deletions(-)
> 
> diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
> index ed946df..6166847 100644
> --- a/arch/arm/mach-omap2/gpmc.c
> +++ b/arch/arm/mach-omap2/gpmc.c
> @@ -1520,32 +1520,19 @@ static int gpmc_probe_dt(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	for_each_node_by_name(child, "nand") {
> -		ret = gpmc_probe_nand_child(pdev, child);
> -		if (ret < 0) {
> -			of_node_put(child);
> -			return ret;
> -		}
> -	}
> +	for_each_child_of_node(pdev->dev.of_node, child) {
>  
> -	for_each_node_by_name(child, "onenand") {
> -		ret = gpmc_probe_onenand_child(pdev, child);
> -		if (ret < 0) {
> -			of_node_put(child);
> -			return ret;
> -		}
> -	}
> +		if (!child->name)
> +			continue;
>  
> -	for_each_node_by_name(child, "nor") {
> -		ret = gpmc_probe_generic_child(pdev, child);
> -		if (ret < 0) {
> -			of_node_put(child);
> -			return ret;
> -		}
> -	}
> +		if (of_node_cmp(child->name, "nand") == 0)
> +			ret = gpmc_probe_nand_child(pdev, child);
> +		else if (of_node_cmp(child->name, "onenand") == 0)
> +			ret = gpmc_probe_onenand_child(pdev, child);
> +		else if (of_node_cmp(child->name, "ethernet") == 0 ||
> +			 of_node_cmp(child->name, "nor") == 0)
> +			ret = gpmc_probe_generic_child(pdev, child);
>  
> -	for_each_node_by_name(child, "ethernet") {
> -		ret = gpmc_probe_generic_child(pdev, child);
>  		if (ret < 0) {

I think that we need to make sure that "ret" is initialised to 0 at the
beginning of the function. We should not have a case where the child
name does not match but who knows. Actually that raises another point,
should we have an "else" clause at the end that WARNs on
"unknown/unsupported child" device?

>  			of_node_put(child);
>  			return ret;
> 

Otherwise looks great.

Cheers
Jon