dm: core: Add an implementation of regmap_init_mem_platdata()

Add an implementation of this function which mirrors the functions of the
automatic device-tree implementation. This can be used with of-platdata to
create regmaps.
Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/core/regmap.c

@@ -37,10 +37,24 @@ static struct regmap *regmap_alloc_count(int count)
 }
 
 #if CONFIG_IS_ENABLED(OF_PLATDATA)
-int regmap_init_mem_platdata(struct udevice *dev, fdt32_t *reg, int size,
+int regmap_init_mem_platdata(struct udevice *dev, u32 *reg, int count,
 			     struct regmap **mapp)
 {
-	/* TODO(sjg@chromium.org): Implement this when needed */
+	struct regmap_range *range;
+	struct regmap *map;
+
+	map = regmap_alloc_count(count);
+	if (!map)
+		return -ENOMEM;
+
+	map->base = *reg;
+	for (range = map->range; count > 0; reg += 2, range++, count--) {
+		range->start = *reg;
+		range->size = reg[1];
+	}
+
+	*mapp = map;
+
 	return 0;
 }
 #else

include/regmap.h

@@ -56,7 +56,20 @@ int regmap_read(struct regmap *map, uint offset, uint *valp);
  */
 int regmap_init_mem(struct udevice *dev, struct regmap **mapp);
 
-int regmap_init_mem_platdata(struct udevice *dev, fdt32_t *reg, int size,
+/**
+ * regmap_init_mem_platdata() - Set up a new memory register map for of-platdata
+ *
+ * This creates a new regmap with a list of regions passed in, rather than
+ * using the device tree. It only supports 32-bit machines.
+ *
+ * Use regmap_uninit() to free it.
+ *
+ * @dev:	Device that uses this map
+ * @reg:	List of address, size pairs
+ * @count:	Number of pairs (e.g. 1 if the regmap has a single entry)
+ * @mapp:	Returns allocated map
+ */
+int regmap_init_mem_platdata(struct udevice *dev, u32 *reg, int count,
 			     struct regmap **mapp);
 
 /**