regmap: Skip precious registers when dumping registers via debugfs

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 78f87f3..a67dc68 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -45,6 +45,7 @@
 	bool (*writeable_reg)(struct device *dev, unsigned int reg);
 	bool (*readable_reg)(struct device *dev, unsigned int reg);
 	bool (*volatile_reg)(struct device *dev, unsigned int reg);
+	bool (*precious_reg)(struct device *dev, unsigned int reg);
 };
 
 #ifdef CONFIG_DEBUG_FS
diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index 2be8bf8..184b618 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -56,6 +56,10 @@
 		    !map->readable_reg(map->dev, i))
 			continue;
 
+		if (map->precious_reg &&
+		    map->precious_reg(map->dev, i))
+			continue;
+
 		/* If we're in the region the user is trying to read */
 		if (p >= *ppos) {
 			/* ...but not beyond it */
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index a3eaef6..d74d306 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -101,6 +101,7 @@
 	map->writeable_reg = config->writeable_reg;
 	map->readable_reg = config->readable_reg;
 	map->volatile_reg = config->volatile_reg;
+	map->precious_reg = config->precious_reg;
 
 	switch (config->reg_bits) {
 	case 4: