regmap: add regmap_might_sleep()

With the dawn of MMIO gpio-regmap users, it is desirable to let
gpio-regmap ask the regmap if it might sleep during an access so
it can pass that information to gpiochip. Add a new regmap_might_sleep()
to query the regmap.

Signed-off-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20221121150843.1562603-1-michael@walle.cc
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/base/regmap/regmap.c

@@ -3486,6 +3486,19 @@ int regmap_get_reg_stride(struct regmap *map)
 }
 EXPORT_SYMBOL_GPL(regmap_get_reg_stride);
 
+/**
+ * regmap_might_sleep() - Returns whether a regmap access might sleep.
+ *
+ * @map: Register map to operate on.
+ *
+ * Returns true if an access to the register might sleep, else false.
+ */
+bool regmap_might_sleep(struct regmap *map)
+{
+	return map->can_sleep;
+}
+EXPORT_SYMBOL_GPL(regmap_might_sleep);
+
 int regmap_parse_val(struct regmap *map, const void *buf,
 			unsigned int *val)
 {

include/linux/regmap.h

@@ -1219,6 +1219,7 @@ static inline int regmap_write_bits(struct regmap *map, unsigned int reg,
 int regmap_get_val_bytes(struct regmap *map);
 int regmap_get_max_register(struct regmap *map);
 int regmap_get_reg_stride(struct regmap *map);
+bool regmap_might_sleep(struct regmap *map);
 int regmap_async_complete(struct regmap *map);
 bool regmap_can_raw_write(struct regmap *map);
 size_t regmap_get_raw_read_max(struct regmap *map);
@@ -1905,6 +1906,12 @@ static inline int regmap_get_reg_stride(struct regmap *map)
 	return -EINVAL;
 }
 
+static inline bool regmap_might_sleep(struct regmap *map)
+{
+	WARN_ONCE(1, "regmap API is disabled");
+	return true;
+}
+
 static inline int regcache_sync(struct regmap *map)
 {
 	WARN_ONCE(1, "regmap API is disabled");