2 files changed, 138 insertions, 0 deletions

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index ae23d8391aa0..29c83160ca29 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -176,6 +176,14 @@ struct regmap_range_node {
         unsigned int window_len;
 };
 
+struct regmap_field {
+        struct regmap *regmap;
+        unsigned int mask;
+        /* lsb */
+        unsigned int shift;
+        unsigned int reg;
+};
+
 #ifdef CONFIG_DEBUG_FS
 extern void regmap_debugfs_initcall(void);
 extern void regmap_debugfs_init(struct regmap *map, const char *name);
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index ed152e3d2d88..95920583e31e 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -807,6 +807,95 @@ struct regmap *devm_regmap_init(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(devm_regmap_init);
 
+static void regmap_field_init(struct regmap_field *rm_field,
+        struct regmap *regmap, struct reg_field reg_field)
+{
+        int field_bits = reg_field.msb - reg_field.lsb + 1;
+        rm_field->regmap = regmap;
+        rm_field->reg = reg_field.reg;
+        rm_field->shift = reg_field.lsb;
+        rm_field->mask = ((BIT(field_bits) - 1) << reg_field.lsb);
+}
+
+/**
+ * devm_regmap_field_alloc(): Allocate and initialise a register field
+ * in a register map.
+ *
+ * @dev: Device that will be interacted with
+ * @regmap: regmap bank in which this register field is located.
+ * @reg_field: Register field with in the bank.
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer
+ * to a struct regmap_field. The regmap_field will be automatically freed
+ * by the device management code.
+ */
+struct regmap_field *devm_regmap_field_alloc(struct device *dev,
+                struct regmap *regmap, struct reg_field reg_field)
+{
+        struct regmap_field *rm_field = devm_kzalloc(dev,
+                                        sizeof(*rm_field), GFP_KERNEL);
+        if (!rm_field)
+                return ERR_PTR(-ENOMEM);
+
+        regmap_field_init(rm_field, regmap, reg_field);
+
+        return rm_field;
+
+}
+EXPORT_SYMBOL_GPL(devm_regmap_field_alloc);
+
+/**
+ * devm_regmap_field_free(): Free register field allocated using
+ * devm_regmap_field_alloc. Usally drivers need not call this function,
+ * as the memory allocated via devm will be freed as per device-driver
+ * life-cyle.
+ *
+ * @dev: Device that will be interacted with
+ * @field: regmap field which should be freed.
+ */
+void devm_regmap_field_free(struct device *dev,
+        struct regmap_field *field)
+{
+        devm_kfree(dev, field);
+}
+EXPORT_SYMBOL_GPL(devm_regmap_field_free);
+
+/**
+ * regmap_field_alloc(): Allocate and initialise a register field
+ * in a register map.
+ *
+ * @regmap: regmap bank in which this register field is located.
+ * @reg_field: Register field with in the bank.
+ *
+ * The return value will be an ERR_PTR() on error or a valid pointer
+ * to a struct regmap_field. The regmap_field should be freed by the
+ * user once its finished working with it using regmap_field_free().
+ */
+struct regmap_field *regmap_field_alloc(struct regmap *regmap,
+                struct reg_field reg_field)
+{
+        struct regmap_field *rm_field = kzalloc(sizeof(*rm_field), GFP_KERNEL);
+
+        if (!rm_field)
+                return ERR_PTR(-ENOMEM);
+
+        regmap_field_init(rm_field, regmap, reg_field);
+
+        return rm_field;
+}
+EXPORT_SYMBOL_GPL(regmap_field_alloc);
+
+/**
+ * regmap_field_free(): Free register field allocated using regmap_field_alloc
+ *
+ * @field: regmap field which should be freed.
+ */
+void regmap_field_free(struct regmap_field *field)
+{
+        kfree(field);
+}
+EXPORT_SYMBOL_GPL(regmap_field_free);
+
 /**
  * regmap_reinit_cache(): Reinitialise the current register cache
  *
@@ -1255,6 +1344,22 @@ int regmap_raw_write(struct regmap *map, unsigned int reg,
 }
 EXPORT_SYMBOL_GPL(regmap_raw_write);
 
+/**
+ * regmap_field_write(): Write a value to a single register field
+ *
+ * @field: Register field to write to
+ * @val: Value to be written
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_field_write(struct regmap_field *field, unsigned int val)
+{
+        return regmap_update_bits(field->regmap, field->reg,
+                                field->mask, val << field->shift);
+}
+EXPORT_SYMBOL_GPL(regmap_field_write);
+
 /*
  * regmap_bulk_write(): Write multiple registers to the device
  *
@@ -1538,6 +1643,31 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 EXPORT_SYMBOL_GPL(regmap_raw_read);
 
 /**
+ * regmap_field_read(): Read a value to a single register field
+ *
+ * @field: Register field to read from
+ * @val: Pointer to store read value
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_field_read(struct regmap_field *field, unsigned int *val)
+{
+        int ret;
+        unsigned int reg_val;
+        ret = regmap_read(field->regmap, field->reg, &reg_val);
+        if (ret != 0)
+                return ret;
+
+        reg_val &= field->mask;
+        reg_val >>= field->shift;
+        *val = reg_val;
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_field_read);
+
+/**
  * regmap_bulk_read(): Read multiple registers from the device
  *
  * @map: Register map to write to