Re: [PATCH v2 01/11] mtd: add get/set of_node/flash_node helpers

[Boris Brezillon <boris.brezillon@free-electrons.com>]

On Fri, 30 Oct 2015 20:33:20 -0700
Brian Norris <computersforpeace@gmail.com> wrote:

> We are going to begin using the mtd->dev.of_node field for MTD device
> nodes, so let's add helpers for it. Also, we'll be making some
> conversions on spi_nor (and nand_chip eventually) too, so get that ready
> with their own helpers.
> 
> Signed-off-by: Brian Norris <computersforpeace@gmail.com>
> ---
> v2: new
> 
>  include/linux/mtd/mtd.h     | 11 +++++++++++
>  include/linux/mtd/nand.h    | 11 +++++++++++
>  include/linux/mtd/spi-nor.h | 11 +++++++++++
>  3 files changed, 33 insertions(+)
> 
> diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
> index f17fa75809aa..cc84923011c0 100644
> --- a/include/linux/mtd/mtd.h
> +++ b/include/linux/mtd/mtd.h
> @@ -254,6 +254,17 @@ struct mtd_info {
>  	int usecount;
>  };
>  
> +static inline void mtd_set_of_node(struct mtd_info *mtd,
> +				   struct device_node *np)
> +{
> +	mtd->dev.of_node = np;

Maybe we should retain a reference to the device_node here (IOW,
replace '= np' by '= of_node_get(np)'). Of course this implies calling
of_node_put() when the mtd device is unregistered.

> +}
> +
> +static inline struct device_node *mtd_get_of_node(struct mtd_info *mtd)
> +{
> +	return mtd->dev.of_node;

Not sure this is relevant to to the same here before returning the
device_node because it's mostly used by the MTD drivers and those are
the ones who called mtd_set_of_node() in the first place, so we can
assume it's safe to return an non-retained reference to a device_node.


-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com