Re: [PATCH 2/3] mtd: ofpart: do not fail probe when no partitions exist

[Brian Norris <computersforpeace@gmail.com>]

On Mon, Jul 27, 2015 at 08:30:43PM -0000, Michal Suchanek wrote:
...
> The controller-data node contains no partition information and no other
> subnodes with partition information exist.
> 
> The ofpart code returns an error when there are subnodes of the flash DT
> node but no partitions are found. This error is then propagated to
> mtdpart which propagetes it to MTD probe which fails probing the flash
> device.
> 
> Change this condition to a warning so that flash without partitions can
> be accessed on Exynos with ofpart support compiled in.

You never replied to my suggestion here:

http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/352206.html

Particularly, "just define a proper compatibile property for [the
'controller-data'] subnode, and ofpart.c will naturally handle this".

> Signed-off-by: Michal Suchanek <hramrach@gmail.com>
> 
> --
>  - add more verbose explanation
> ---
>  drivers/mtd/ofpart.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/ofpart.c b/drivers/mtd/ofpart.c
> index aa26c32..a29d29f 100644
> --- a/drivers/mtd/ofpart.c
> +++ b/drivers/mtd/ofpart.c
> @@ -94,10 +94,10 @@ static int parse_ofpart_partitions(struct mtd_info *master,
>  
>  	if (!i) {
>  		of_node_put(pp);
> -		pr_err("No valid partition found on %s\n", node->full_name);
> +		pr_warn("No valid partition found on %s\n", node->full_name);
>  		kfree(*pparts);
>  		*pparts = NULL;
> -		return -EINVAL;
> +		return 0;

I don't really like this, since it can turn other invalid device trees
into a silent fallback. I'd really prefer we make it easy to tell the
difference between a MTD partition subnode and another foo-bar subnode.

>  	}
>  
>  	return nr_parts;

Brian