[PATCH v2 06/15] nvmem: core: expose nvmem cells as cdev

[Marco Felsch]

On 25-08-20, Sascha Hauer wrote:
> On Mon, Aug 18, 2025 at 07:44:40PM +0200, Marco Felsch wrote:
> > Linux has added the support to expose nvmem-cells via the sysfs by
> > commit 0331c611949f ("nvmem: core: Expose cells through sysfs"). This
> > commit adds an equivalent mechanism by exposing the nvmem-cells via
> > cdevs. The name scheme is: <nvmem-dev-name>.<cell-name>.
> > 
> > With this in place it is possible for board code and/or shell to query
> > the nvmem-cell values without specifying the consumer API within DT. At
> > the moment the access is RO like Linux does since write support requires
> > more corner case handling.
> > 
> > The naming scheme for nvmem_populate_sysfs_cells() was kept to reduce the
> > Linux diff.
> > 
> > Signed-off-by: Marco Felsch <m.felsch at pengutronix.de>
> > ---
> >  drivers/nvmem/core.c | 93 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 93 insertions(+)
> > 
> > diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> > index c252f17ef0b24e8199e199db086aeec8d09fdf94..4dbeb1e116ae398f1f2748238d97468c1096262a 100644
> > --- a/drivers/nvmem/core.c
> > +++ b/drivers/nvmem/core.c
> > @@ -45,6 +45,8 @@ struct nvmem_cell_entry {
> >  	struct device_node	*np;
> >  	struct nvmem_device	*nvmem;
> >  	struct list_head	node;
> > +
> > +	struct cdev		cdev;
> >  };
> >  
> >  struct nvmem_cell {
> > @@ -167,6 +169,71 @@ static struct nvmem_device *of_nvmem_find(struct device_node *nvmem_np)
> >  	return NULL;
> >  }
> >  
> > +static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry,
> > +					    const char *id, int index);
> 
> This causes intermediate breakage. The prototype at this point is still:
> 
> static struct nvmem_cell *nvmem_create_cell(struct nvmem_cell_entry *entry,
> 					    const char *id);
> 
> The index parameter is only added later in this series.

Argh.. I didn't noticed this sorry.

Regards,
  Marco

> 
> Sascha
> 
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