regmap: Add asynchronous I/O support

Some use cases like firmware download can transfer a lot of data in quick
succession. With high speed buses these use cases can benefit from having
multiple transfers scheduled at once since this allows the bus to minimise
the delay between transfers.

Support this by adding regmap_raw_write_async(), allowing raw transfers to
be scheduled, and regmap_async_complete() to wait for them to finish.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index b7e95bf942c9..f9b7fbe35ab1 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -235,14 +235,21 @@ struct regmap_range_cfg {
 	unsigned int window_len;
 };
 
+struct regmap_async;
+
 typedef int (*regmap_hw_write)(void *context, const void *data,
 			       size_t count);
 typedef int (*regmap_hw_gather_write)(void *context,
 				      const void *reg, size_t reg_len,
 				      const void *val, size_t val_len);
+typedef int (*regmap_hw_async_write)(void *context,
+				     const void *reg, size_t reg_len,
+				     const void *val, size_t val_len,
+				     struct regmap_async *async);
 typedef int (*regmap_hw_read)(void *context,
 			      const void *reg_buf, size_t reg_size,
 			      void *val_buf, size_t val_size);
+typedef struct regmap_async *(*regmap_hw_async_alloc)(void);
 typedef void (*regmap_hw_free_context)(void *context);
 
 /**
@@ -255,8 +262,11 @@ typedef void (*regmap_hw_free_context)(void *context);
  * @write: Write operation.
  * @gather_write: Write operation with split register/value, return -ENOTSUPP
  *                if not implemented  on a given device.
+ * @async_write: Write operation which completes asynchronously, optional and
+ *               must serialise with respect to non-async I/O.
  * @read: Read operation.  Data is returned in the buffer used to transmit
  *         data.
+ * @async_alloc: Allocate a regmap_async() structure.
  * @read_flag_mask: Mask to be set in the top byte of the register when doing
  *                  a read.
  * @reg_format_endian_default: Default endianness for formatted register
@@ -265,13 +275,16 @@ typedef void (*regmap_hw_free_context)(void *context);
  * @val_format_endian_default: Default endianness for formatted register
  *     values. Used when the regmap_config specifies DEFAULT. If this is
  *     DEFAULT, BIG is assumed.
+ * @async_size: Size of struct used for async work.
  */
 struct regmap_bus {
 	bool fast_io;
 	regmap_hw_write write;
 	regmap_hw_gather_write gather_write;
+	regmap_hw_async_write async_write;
 	regmap_hw_read read;
 	regmap_hw_free_context free_context;
+	regmap_hw_async_alloc async_alloc;
 	u8 read_flag_mask;
 	enum regmap_endian reg_format_endian_default;
 	enum regmap_endian val_format_endian_default;
@@ -310,6 +323,8 @@ int regmap_raw_write(struct regmap *map, unsigned int reg,
 		     const void *val, size_t val_len);
 int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
 			size_t val_count);
+int regmap_raw_write_async(struct regmap *map, unsigned int reg,
+			   const void *val, size_t val_len);
 int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val);
 int regmap_raw_read(struct regmap *map, unsigned int reg,
 		    void *val, size_t val_len);
@@ -321,6 +336,7 @@ int regmap_update_bits_check(struct regmap *map, unsigned int reg,
 			     unsigned int mask, unsigned int val,
 			     bool *change);
 int regmap_get_val_bytes(struct regmap *map);
+int regmap_async_complete(struct regmap *map);
 
 int regcache_sync(struct regmap *map);
 int regcache_sync_region(struct regmap *map, unsigned int min,
@@ -422,6 +438,13 @@ static inline int regmap_raw_write(struct regmap *map, unsigned int reg,
 	return -EINVAL;
 }
 
+static inline int regmap_raw_write_async(struct regmap *map, unsigned int reg,
+					 const void *val, size_t val_len)
+{
+	WARN_ONCE(1, "regmap API is disabled");
+	return -EINVAL;
+}
+
 static inline int regmap_bulk_write(struct regmap *map, unsigned int reg,
 				    const void *val, size_t val_count)
 {
@@ -500,6 +523,11 @@ static inline void regcache_mark_dirty(struct regmap *map)
 	WARN_ONCE(1, "regmap API is disabled");
 }
 
+static inline void regmap_async_complete(struct regmap *map)
+{
+	WARN_ONCE(1, "regmap API is disabled");
+}
+
 static inline int regmap_register_patch(struct regmap *map,
 					const struct reg_default *regs,
 					int num_regs)