regmap: Allow installing custom reg_update_bits function

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@gridpoint.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index cc557886ab2377a550c1ae529b6ecee23380161f..628ad7ac078b9b0cbb16cd4720ce1a92ac3f8a82 100644 (file)
--- 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 afaf56200674a29517678af763bc9a084659224b..8cd155af3d63346fb51b28f78691dbabfefcc510 100644 (file)
--- 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 8fc0bfd8edc4434fc79fda8591323d6be41f0645..b49d4133750ec4b224d04660283513c73bd3a36a 100644 (file)
--- 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;