regmap: Add functions to check for access on registers

We're going to be using these in quite a few places so factor out the
readable/writable/volatile/precious checks.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/internal.h

@@ -48,6 +48,11 @@ struct regmap {
 	bool (*precious_reg)(struct device *dev, unsigned int reg);
 };
 
+bool regmap_writeable(struct regmap *map, unsigned int reg);
+bool regmap_readable(struct regmap *map, unsigned int reg);
+bool regmap_volatile(struct regmap *map, unsigned int reg);
+bool regmap_precious(struct regmap *map, unsigned int reg);
+
 #ifdef CONFIG_DEBUG_FS
 extern void regmap_debugfs_initcall(void);
 extern void regmap_debugfs_init(struct regmap *map);

drivers/base/regmap/regmap-debugfs.c

@@ -52,12 +52,10 @@ static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
 	tot_len = reg_len + val_len + 3;      /* : \n */
 
 	for (i = 0; i < map->max_register; i++) {
-		if (map->readable_reg &&
-		    !map->readable_reg(map->dev, i))
+		if (!regmap_readable(map, i))
 			continue;
 
-		if (map->precious_reg &&
-		    map->precious_reg(map->dev, i))
+		if (regmap_precious(map, i))
 			continue;
 
 		/* If we're in the region the user is trying to read */

drivers/base/regmap/regmap.c

@@ -20,6 +20,50 @@
 
 #include "internal.h"
 
+bool regmap_writeable(struct regmap *map, unsigned int reg)
+{
+	if (map->max_register && reg > map->max_register)
+		return false;
+
+	if (map->writeable_reg)
+		return map->writeable_reg(map->dev, reg);
+
+	return true;
+}
+
+bool regmap_readable(struct regmap *map, unsigned int reg)
+{
+	if (map->max_register && reg > map->max_register)
+		return false;
+
+	if (map->readable_reg)
+		return map->readable_reg(map->dev, reg);
+
+	return true;
+}
+
+bool regmap_volatile(struct regmap *map, unsigned int reg)
+{
+	if (map->max_register && reg > map->max_register)
+		return false;
+
+	if (map->volatile_reg)
+		return map->volatile_reg(map->dev, reg);
+
+	return true;
+}
+
+bool regmap_precious(struct regmap *map, unsigned int reg)
+{
+	if (map->max_register && reg > map->max_register)
+		return false;
+
+	if (map->precious_reg)
+		return map->precious_reg(map->dev, reg);
+
+	return false;
+}
+
 static void regmap_format_4_12_write(struct regmap *map,
 				     unsigned int reg, unsigned int val)
 {