nvmem: add support for cell lookups from machine code

Add a way for machine code users to associate devices with nvmem cells.

This restores the support for non-DT systems but following a different
approach. Cells must now be associated with devices using provided
routines and data structures before they can be retrieved using
nvmem_cell_get().

It's still possible to define cells statically in nvmem_config but
cells created this way still need to be associated with consumers using
lookup entries.

Note that nvmem_find() must be moved higher in the source file as we
want to call it from __nvmem_device_get() for devices that don't have
a device node.

The signature of __nvmem_device_get() is also changed as it's no longer
used to retrieve cells.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/include/linux/nvmem-consumer.h b/include/linux/nvmem-consumer.h
index 0389fe00b177..27eee3945405 100644
--- a/include/linux/nvmem-consumer.h
+++ b/include/linux/nvmem-consumer.h
@@ -29,6 +29,24 @@ struct nvmem_cell_info {
 	unsigned int		nbits;
 };
 
+/**
+ * struct nvmem_cell_lookup - cell lookup entry
+ *
+ * @nvmem_name:	Name of the provider.
+ * @cell_name:	Name of the nvmem cell as defined in the name field of
+ *		struct nvmem_cell_info.
+ * @dev_id:	Name of the consumer device that will be associated with
+ *		this cell.
+ * @con_id:	Connector id for this cell lookup.
+ */
+struct nvmem_cell_lookup {
+	const char		*nvmem_name;
+	const char		*cell_name;
+	const char		*dev_id;
+	const char		*con_id;
+	struct list_head	node;
+};
+
 #if IS_ENABLED(CONFIG_NVMEM)
 
 /* Cell based interface */
@@ -57,6 +75,11 @@ int nvmem_device_cell_write(struct nvmem_device *nvmem,
 
 const char *nvmem_dev_name(struct nvmem_device *nvmem);
 
+void nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries,
+			    size_t nentries);
+void nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries,
+			    size_t nentries);
+
 #else
 
 static inline struct nvmem_cell *nvmem_cell_get(struct device *dev,
@@ -151,6 +174,11 @@ static inline const char *nvmem_dev_name(struct nvmem_device *nvmem)
 	return NULL;
 }
 
+static inline void
+nvmem_add_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries) {}
+static inline void
+nvmem_del_cell_lookups(struct nvmem_cell_lookup *entries, size_t nentries) {}
+
 #endif /* CONFIG_NVMEM */
 
 #if IS_ENABLED(CONFIG_NVMEM) && IS_ENABLED(CONFIG_OF)