regmap: Add "no-bus" option for regmap API

This commit adds provision for "no-bus" usage of the regmap API. In
this configuration user can provide API with two callbacks 'reg_read'
and 'reg_write' which are to be called when reads and writes to one of
device's registers is performed. This is useful for devices that
expose registers but whose register access sequence does not fit the 'bus'
abstraction.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index b7e95bf942c9..28dde941c783 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -127,7 +127,18 @@ typedef void (*regmap_unlock)(void *);
  * @lock_arg:     this field is passed as the only argument of lock/unlock
  *                functions (ignored in case regular lock/unlock functions
  *                are not overridden).
- *
+ * @reg_read:     Optional callback that if filled will be used to perform
+ *                all the reads from the registers. Should only be provided for
+ *                devices whos read operation cannot be represented as a simple read
+ *                operation on a bus such as SPI, I2C, etc. Most of the devices do
+ *                not need this.
+ * @reg_write:    Same as above for writing.
+ * @fast_io:      Register IO is fast. Use a spinlock instead of a mutex
+ *                to perform locking. This field is ignored if custom lock/unlock
+ *                functions are used (see fields lock/unlock of struct regmap_config).
+ *                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.
  * @max_register: Optional, specifies the maximum valid register index.
  * @wr_table:     Optional, points to a struct regmap_access_table specifying
  *                valid ranges for write access.
@@ -177,6 +188,11 @@ struct regmap_config {
         regmap_unlock unlock;
         void *lock_arg;
 
+        int (*reg_read)(void *context, unsigned int reg, unsigned int *val);
+        int (*reg_write)(void *context, unsigned int reg, unsigned int val);
+
+        bool fast_io;
+
         unsigned int max_register;
         const struct regmap_access_table *wr_table;
         const struct regmap_access_table *rd_table;