nvmem: add support for cell info

Add new structs and routines allowing users to define nvmem cells from
machine code. This global list of entries is parsed when a provider
is registered and cells are associated with the relevant nvmem_device
struct.

A possible improvement for the future is to allow users to register
cell tables after the nvmem provider has been registered by updating
the cell list at each call to nvmem_(add|del)_cell_table().

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, 24 insertions, 9 deletions

diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
index 0f357d0c1e75..5c9f205cac8f 100644
--- a/include/linux/nvmem-provider.h
+++ b/include/linux/nvmem-provider.h
@@ -67,6 +67,25 @@ struct nvmem_config {
         struct device           *base_dev;
 };
 
+/**
+ * struct nvmem_cell_table - NVMEM cell definitions for given provider
+ *
+ * @nvmem_name:         Provider name.
+ * @cells:              Array of cell definitions.
+ * @ncells:             Number of cell definitions in the array.
+ * @node:               List node.
+ *
+ * This structure together with related helper functions is provided for users
+ * that don't can't access the nvmem provided structure but wish to register
+ * cell definitions for it e.g. board files registering an EEPROM device.
+ */
+struct nvmem_cell_table {
+        const char              *nvmem_name;
+        const struct nvmem_cell_info    *cells;
+        size_t                  ncells;
+        struct list_head        node;
+};
+
 #if IS_ENABLED(CONFIG_NVMEM)
 
 struct nvmem_device *nvmem_register(const struct nvmem_config *cfg);
@@ -77,9 +96,9 @@ struct nvmem_device *devm_nvmem_register(struct device *dev,
 
 int devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem);
 
-int nvmem_add_cells(struct nvmem_device *nvmem,
-                    const struct nvmem_cell_info *info,
-                    int ncells);
+void nvmem_add_cell_table(struct nvmem_cell_table *table);
+void nvmem_del_cell_table(struct nvmem_cell_table *table);
+
 #else
 
 static inline struct nvmem_device *nvmem_register(const struct nvmem_config *c)
@@ -102,12 +121,8 @@ devm_nvmem_unregister(struct device *dev, struct nvmem_device *nvmem)
 
 }
 
-static inline int nvmem_add_cells(struct nvmem_device *nvmem,
-                                  const struct nvmem_cell_info *info,
-                                  int ncells)
-{
-        return -ENOSYS;
-}
+static inline void nvmem_add_cell_table(struct nvmem_cell_table *table) {}
+static inline void nvmem_del_cell_table(struct nvmem_cell_table *table) {}
 
 #endif /* CONFIG_NVMEM */
 #endif  /* ifndef _LINUX_NVMEM_PROVIDER_H */