[RFC PATCH v2] regmap: apply reg_base and reg_downshift for single register ops

[Daniel Golle]

reg_base and reg_downshift currently don't have any effect if used with
a regmap_bus or regmap_config which only offers single register
operations (ie. reg_read, reg_write and optionally reg_update_bits).

Fix that and take them into account also for regmap_bus with only
reg_read and read_write operations by applying reg_base and
reg_downshift in _regmap_bus_reg_write, _regmap_bus_reg_read.

Also apply reg_base and reg_downshift in _regmap_update_bits, but only
in case the operation is carried out with a reg_update_bits call
defined in either regmap_bus or regmap_config.

Fixes: 0074f3f2b1e43d ("regmap: allow a defined reg_base to be added to every address")
Fixes: 86fc59ef818beb ("regmap: add configurable downshift for addresses")
Signed-off-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>
---
I hope that I didn't miss anything there...

@Colin Please let me know if this breaks anything with your ocelot_spi
use-case.

 drivers/base/regmap/regmap.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index d12d669157f24..d2a54eb0efd9b 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1942,6 +1942,8 @@ static int _regmap_bus_reg_write(void *context, unsigned int reg,
 {
 	struct regmap *map = context;
 
+	reg += map->reg_base;
+	reg >>= map->format.reg_downshift;
 	return map->bus->reg_write(map->bus_context, reg, val);
 }
 
@@ -2840,6 +2842,8 @@ static int _regmap_bus_reg_read(void *context, unsigned int reg,
 {
 	struct regmap *map = context;
 
+	reg += map->reg_base;
+	reg >>= map->format.reg_downshift;
 	return map->bus->reg_read(map->bus_context, reg, val);
 }
 
@@ -3231,6 +3235,8 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg,
 		*change = false;
 
 	if (regmap_volatile(map, reg) && map->reg_update_bits) {
+		reg += map->reg_base;
+		reg >>= map->format.reg_downshift;
 		ret = map->reg_update_bits(map->bus_context, reg, mask, val);
 		if (ret == 0 && change)
 			*change = true;
-- 
2.39.1