nvmem: core: allow to modify a cell before adding it

Provide a way to modify a cell before it will get added. This is useful
to attach a custom post processing hook via a layout.
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-18-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/core.c

@@ -695,6 +695,7 @@ static int nvmem_validate_keepouts(struct nvmem_device *nvmem)
 
 static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
 {
+	struct nvmem_layout *layout = nvmem->layout;
 	struct device *dev = &nvmem->dev;
 	struct device_node *child;
 	const __be32 *addr;
@@ -724,6 +725,9 @@ static int nvmem_add_cells_from_of(struct nvmem_device *nvmem)
 
 		info.np = of_node_get(child);
 
+		if (layout && layout->fixup_cell_info)
+			layout->fixup_cell_info(nvmem, layout, &info);
+
 		ret = nvmem_add_one_cell(nvmem, &info);
 		kfree(info.name);
 		if (ret) {

include/linux/nvmem-provider.h

@@ -155,6 +155,8 @@ struct nvmem_cell_table {
  * @add_cells:		Will be called if a nvmem device is found which
  *			has this layout. The function will add layout
  *			specific cells with nvmem_add_one_cell().
+ * @fixup_cell_info:	Will be called before a cell is added. Can be
+ *			used to modify the nvmem_cell_info.
  * @owner:		Pointer to struct module.
  * @node:		List node.
  *
@@ -168,6 +170,9 @@ struct nvmem_layout {
 	const struct of_device_id *of_match_table;
 	int (*add_cells)(struct device *dev, struct nvmem_device *nvmem,
 			 struct nvmem_layout *layout);
+	void (*fixup_cell_info)(struct nvmem_device *nvmem,
+				struct nvmem_layout *layout,
+				struct nvmem_cell_info *cell);
 
 	/* private */
 	struct module *owner;