regmap: introduce fast_io busses, and use a spinlock for them
Some bus types have very fast IO. For these, acquiring a mutex for every
IO operation is a significant overhead. Allow busses to indicate their IO
is fast, and enhance regmap to use a spinlock for those busses.
[Currently limited to native endian registers -- broonie]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 8fd341e..f14588a 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -110,6 +110,8 @@
/**
* Description of a hardware bus for the register map infrastructure.
*
+ * @fast_io: Register IO is fast. Use a spinlock instead of a mutex
+ * to perform locking.
* @write: Write operation.
* @gather_write: Write operation with split register/value, return -ENOTSUPP
* if not implemented on a given device.
@@ -119,6 +121,7 @@
* a read.
*/
struct regmap_bus {
+ bool fast_io;
regmap_hw_write write;
regmap_hw_gather_write gather_write;
regmap_hw_read read;