regmap: mmio: Introduce IO accessors that can talk to IO port

Some users may use regmap MMIO for IO ports, and this can be done
by assigning ioreadXX()/iowriteXX() and their Big Endian counterparts
to the regmap context.

Add IO port support with a corresponding flag added.

While doing that, make sure that user won't select relaxed MMIO access
along with IO port because the latter have no relaxed variants.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/20220808203401.35153-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 7cf2157134ac..8cccc247cd37 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -311,6 +311,8 @@ typedef void (*regmap_unlock)(void *);
  *		  This field is a duplicate of a similar file in
  *		  'struct regmap_bus' and serves exact same purpose.
  *		   Use it only for "no-bus" cases.
+ * @io_port:	  Support IO port accessors. Makes sense only when MMIO vs. IO port
+ *		  access can be distinguished.
  * @max_register: Optional, specifies the maximum valid register address.
  * @wr_table:     Optional, points to a struct regmap_access_table specifying
  *                valid ranges for write access.
@@ -399,6 +401,7 @@ struct regmap_config {
 	size_t max_raw_write;
 
 	bool fast_io;
+	bool io_port;
 
 	unsigned int max_register;
 	const struct regmap_access_table *wr_table;