[PATCH] regmap: Allow installing custom reg_update_bits function

From: Jon Ringle
Date: Thu Oct 01 2015 - 12:38:07 EST


This commit allows installing a custom reg_update_bits function for cases where
the hardware provides a mechanism to set or clear register bits without a
read/modify/write cycle. Such is the case with the Microchip ENCX24J600.

If a custom reg_update_bits function is provided, it will only be used against
volatile registers.

Signed-off-by: Jon Ringle <jringle@xxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
drivers/base/regmap/internal.h | 2 ++
drivers/base/regmap/regmap.c | 29 ++++++++++++++++++-----------
include/linux/regmap.h | 3 +++
3 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index cc55788..628ad7a 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -98,6 +98,8 @@ struct regmap {

int (*reg_read)(void *context, unsigned int reg, unsigned int *val);
int (*reg_write)(void *context, unsigned int reg, unsigned int val);
+ int (*reg_update_bits)(void *context, unsigned int reg,
+ unsigned int mask, unsigned int val);

bool defer_caching;

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index afaf562..8cd155a 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -619,6 +619,7 @@ struct regmap *__regmap_init(struct device *dev,
goto skip_format_initialization;
} else {
map->reg_read = _regmap_bus_read;
+ map->reg_update_bits = bus->reg_update_bits;
}

reg_endian = regmap_get_reg_endian(bus, config);
@@ -2509,20 +2510,26 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg,
int ret;
unsigned int tmp, orig;

- ret = _regmap_read(map, reg, &orig);
- if (ret != 0)
- return ret;
+ if (change)
+ *change = false;

- tmp = orig & ~mask;
- tmp |= val & mask;
-
- if (force_write || (tmp != orig)) {
- ret = _regmap_write(map, reg, tmp);
- if (change)
+ if (regmap_volatile(map, reg) && map->reg_update_bits) {
+ ret = map->reg_update_bits(map->bus_context, reg, mask, val);
+ if (ret == 0 && change)
*change = true;
} else {
- if (change)
- *change = false;
+ ret = _regmap_read(map, reg, &orig);
+ if (ret != 0)
+ return ret;
+
+ tmp = orig & ~mask;
+ tmp |= val & mask;
+
+ if (force_write || (tmp != orig)) {
+ ret = _regmap_write(map, reg, tmp);
+ if (ret == 0 && change)
+ *change = true;
+ }
}

return ret;
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index 8fc0bfd..b49d413 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -296,6 +296,8 @@ typedef int (*regmap_hw_reg_read)(void *context, unsigned int reg,
unsigned int *val);
typedef int (*regmap_hw_reg_write)(void *context, unsigned int reg,
unsigned int val);
+typedef int (*regmap_hw_reg_update_bits)(void *context, unsigned int reg,
+ unsigned int mask, unsigned int val);
typedef struct regmap_async *(*regmap_hw_async_alloc)(void);
typedef void (*regmap_hw_free_context)(void *context);

@@ -335,6 +337,7 @@ struct regmap_bus {
regmap_hw_gather_write gather_write;
regmap_hw_async_write async_write;
regmap_hw_reg_write reg_write;
+ regmap_hw_reg_update_bits reg_update_bits;
regmap_hw_read read;
regmap_hw_reg_read reg_read;
regmap_hw_free_context free_context;
--
2.5.0

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