regmap: new API regmap_multi_reg_write() definition
New API regmap_multi_reg_write() is defined that allows a set of reg,val
pairs to be written to a I2C client device as one block transfer from the
point of view of a single I2C master system.
A simple demonstration implementation is included that just splits the
block write request into a sequence of single register writes.
The implementation will be modified later to support those I2C clients
that implement the alternative non-standard MULTIWRITE block write mode
so to achieve a single I2C transfer that will be atomic even in multiple
I2C master systems.
Signed-off-by: Anthony Olech <anthony.olech.opensource@diasemi.com>
Signed-off-by: David Dajun Chen <david.chen@diasemi.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 7d689a1..c42ad69 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1439,6 +1439,47 @@
}
EXPORT_SYMBOL_GPL(regmap_bulk_write);
+/*
+ * regmap_multi_reg_write(): Write multiple registers to the device
+ *
+ * where the set of register are supplied in any order
+ *
+ * @map: Register map to write to
+ * @regs: Array of structures containing register,value to be written
+ * @num_regs: Number of registers to write
+ *
+ * This function is intended to be used for writing a large block of data
+ * atomically to the device in single transfer for those I2C client devices
+ * that implement this alternative block write mode.
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_multi_reg_write(struct regmap *map, struct reg_default *regs,
+ int num_regs)
+{
+ int ret = 0, i;
+
+ for (i = 0; i < num_regs; i++) {
+ int reg = regs[i].reg;
+ if (reg % map->reg_stride)
+ return -EINVAL;
+ }
+
+ map->lock(map->lock_arg);
+
+ for (i = 0; i < num_regs; i++) {
+ ret = _regmap_write(map, regs[i].reg, regs[i].def);
+ if (ret != 0)
+ goto out;
+ }
+out:
+ map->unlock(map->lock_arg);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_multi_reg_write);
+
/**
* regmap_raw_write_async(): Write raw values to one or more registers
* asynchronously
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index a10380b..4b933a3 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -378,6 +378,8 @@
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_multi_reg_write(struct regmap *map, struct reg_default *regs,
+ int num_regs);
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);
