[PATCH v1] regmap: Clarify _regmap_update_bits() 'async' kernel-doc

The kernel-doc for the 'async' parameter didn't actually say what it does.

Reword it to clarify the read-modify-write mechanics: when 'async' is true,
the write is queued asynchronously, but the read will still be synchronous
unless the device uses a register cache.

Assisted-by: Gemini:3.1 Pro
Signed-off-by: Bjorn Helgaas <[email protected]>
---
 drivers/base/regmap/regmap.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index e6e022b02637..430dc8233c40 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -3296,11 +3296,11 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg,
  * Perform a read/modify/write cycle on a register map with change, async, force
  * options.
  *
- * If async is true:
- *
- * With most buses the read must be done synchronously so this is most useful
- * for devices with a cache which do not need to interact with the hardware to
- * determine the current register value.
+ * If async is true, queue an asynchronous write. However, most buses
+ * require synchronous reads, so the read-modify-write cycle will still
+ * block on the read unless the device uses a register cache.  Therefore,
+ * this flag is most useful for cached devices, where the current value can
+ * be read from memory without hardware I/O.
  *
  * Returns zero for success, a negative number on error.
  */
-- 
2.53.0