[PATCH v8 4/9] nvmem: layouts: Support fixed-layout as the nvmem device node itself

[Bartosz Golaszewski]

On Wed, 15 Jul 2026 14:07:24 +0200, Bartosz Golaszewski <brgl at kernel.org> said:
> On Fri, 3 Jul 2026 15:45:17 +0200, Loic Poulain <loic.poulain at oss.qualcomm.com> said:
>> of_nvmem_layout_get_container() only looks for a child node named
>> "nvmem-layout" to locate the cell definitions. This does not cover
>> providers whose device tree node is itself the fixed-layout container,
>> such as an eMMC boot partition block device whose fwnode points directly
>> at a "fixed-layout" compatible partitions node.
>>
>> When no "nvmem-layout" child is present, fall back to returning the nvmem
>> device node itself if it is compatible with "fixed-layout", so that its
>> cells are parsed by nvmem_add_cells_from_fixed_layout().
>>
>> Signed-off-by: Loic Poulain <loic.poulain at oss.qualcomm.com>
>> ---
>>  drivers/nvmem/layouts.c | 13 ++++++++++++-
>>  1 file changed, 12 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/nvmem/layouts.c b/drivers/nvmem/layouts.c
>> index b90584e1b99eab4217cbe7ec48373e18a7caf0dc..efa631ce7283bdd6c8ecda75915911b5e3a33c99 100644
>> --- a/drivers/nvmem/layouts.c
>> +++ b/drivers/nvmem/layouts.c
>> @@ -167,7 +167,18 @@ static int nvmem_layout_bus_populate(struct nvmem_device *nvmem,
>>
>>  struct device_node *of_nvmem_layout_get_container(struct nvmem_device *nvmem)
>>  {
>> -	return of_get_child_by_name(nvmem->dev.of_node, "nvmem-layout");
>> +	struct device_node *np;
>> +
>> +	/* Search for nvmem-layout child */
>> +	np = of_get_child_by_name(nvmem->dev.of_node, "nvmem-layout");
>> +	if (np)
>> +		return np;
>> +
>> +	/* The nvmem of_node is itself a fixed-layout node */
>> +	if (of_device_is_compatible(nvmem->dev.of_node, "fixed-layout"))
>> +		return of_node_get(nvmem->dev.of_node);
>> +
>> +	return NULL;
>>  }
>>  EXPORT_SYMBOL_GPL(of_nvmem_layout_get_container);
>>
>>
>> --
>> 2.34.1
>>
>>
>
> I have it on my TODO list to convert nvmem layouts to be fwnode-agnostic. While
> I'm not sure when I'll have the time to look into it, I think it makes sense
> to not introduce any new OF-specific interfaces. Can you make it into:
>
>   struct fwnode_handle *nvmem_layout_get_container_node(struct nvmem_device *nvmem);
>
> by replacing of_get_child_by_name() with fwnode_get_name_child_node() and
> of_device_is_compatible() with device_is_compatible()? That would mean less
> churn in the future.
>
> Other than that, it looks good.
>
> Bart
>

Scratch that, I didn't realize this isn't a new function but a rework of an
existing one.

Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski at oss.qualcomm.com>

Bart