Merge tag 'regmap-noinc-read' into regmap-4.19

regmap: Support non-incrementing registers

Some devices have individual registers that don't autoincrement the
register address during bulk reads but instead repeatedly read the same
value, for example for monitoring GPIOs or ADCs.  Add support for these.

1 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 52bf358e2c73..379505a53722 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -268,6 +268,13 @@ typedef void (*regmap_unlock)(void *);
  *                field is NULL but precious_table (see below) is not, the
  *                check is performed on such table (a register is precious if
  *                it belongs to one of the ranges specified by precious_table).
+ * @readable_noinc_reg: Optional callback returning true if the register
+ *			supports multiple read operations without incrementing
+ *			the register number. If this field is NULL but
+ *			rd_noinc_table (see below) is not, the check is
+ *			performed on such table (a register is no increment
+ *			readable if it belongs to one of the ranges specified
+ *			by rd_noinc_table).
  * @disable_locking: This regmap is either protected by external means or
  *                   is guaranteed not be be accessed from multiple threads.
  *                   Don't use any locking mechanisms.
@@ -295,6 +302,7 @@ typedef void (*regmap_unlock)(void *);
  * @rd_table:     As above, for read access.
  * @volatile_table: As above, for volatile registers.
  * @precious_table: As above, for precious registers.
+ * @rd_noinc_table: As above, for no increment readable registers.
  * @reg_defaults: Power on reset values for registers (for use with
  *                register cache support).
  * @num_reg_defaults: Number of elements in reg_defaults.
@@ -344,6 +352,7 @@ struct regmap_config {
 	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);
+	bool (*readable_noinc_reg)(struct device *dev, unsigned int reg);
 
 	bool disable_locking;
 	regmap_lock lock;
@@ -360,6 +369,7 @@ struct regmap_config {
 	const struct regmap_access_table *rd_table;
 	const struct regmap_access_table *volatile_table;
 	const struct regmap_access_table *precious_table;
+	const struct regmap_access_table *rd_noinc_table;
 	const struct reg_default *reg_defaults;
 	unsigned int num_reg_defaults;
 	enum regcache_type cache_type;
@@ -981,6 +991,8 @@ int regmap_raw_write_async(struct regmap *map, unsigned int reg,
 int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val);
 int regmap_raw_read(struct regmap *map, unsigned int reg,
 		    void *val, size_t val_len);
+int regmap_noinc_read(struct regmap *map, unsigned int reg,
+		      void *val, size_t val_len);
 int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
 		     size_t val_count);
 int regmap_update_bits_base(struct regmap *map, unsigned int reg,
@@ -1231,6 +1243,13 @@ static inline int regmap_raw_read(struct regmap *map, unsigned int reg,
 	return -EINVAL;
 }
 
+static inline int regmap_noinc_read(struct regmap *map, unsigned int reg,
+				    void *val, size_t val_len)
+{
+	WARN_ONCE(1, "regmap API is disabled");
+	return -EINVAL;
+}
+
 static inline int regmap_bulk_read(struct regmap *map, unsigned int reg,
 				   void *val, size_t val_count)
 {