regmap: add support to regmap_field_bulk_alloc/free apis

Usage of regmap_field_alloc becomes much overhead when number of fields
exceed more than 3.
QCOM LPASS driver has extensively converted to use regmap_fields.

Using new bulk api to allocate fields makes it much more cleaner code to read!
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Srinivasa Rao Mandadapu <srivasam@codeaurora.org>
Link: https://lore.kernel.org/r/20200925164856.10315-2-srinivas.kandagatla@linaro.orgSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/base/regmap/regmap.c

@@ -1227,6 +1227,106 @@ struct regmap_field *devm_regmap_field_alloc(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(devm_regmap_field_alloc);
 
+
+/**
+ * regmap_field_bulk_alloc() - Allocate and initialise a bulk register field.
+ *
+ * @regmap: regmap bank in which this register field is located.
+ * @rm_field: regmap register fields within the bank.
+ * @reg_field: Register fields within the bank.
+ * @num_fields: Number of register fields.
+ *
+ * The return value will be an -ENOMEM on error or zero for success.
+ * Newly allocated regmap_fields should be freed by calling
+ * regmap_field_bulk_free()
+ */
+int regmap_field_bulk_alloc(struct regmap *regmap,
+			    struct regmap_field **rm_field,
+			    struct reg_field *reg_field,
+			    int num_fields)
+{
+	struct regmap_field *rf;
+	int i;
+
+	rf = kcalloc(num_fields, sizeof(*rf), GFP_KERNEL);
+	if (!rf)
+		return -ENOMEM;
+
+	for (i = 0; i < num_fields; i++) {
+		regmap_field_init(&rf[i], regmap, reg_field[i]);
+		rm_field[i] = &rf[i];
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(regmap_field_bulk_alloc);
+
+/**
+ * devm_regmap_field_bulk_alloc() - Allocate and initialise a bulk register
+ * fields.
+ *
+ * @dev: Device that will be interacted with
+ * @regmap: regmap bank in which this register field is located.
+ * @rm_field: regmap register fields within the bank.
+ * @reg_field: Register fields within the bank.
+ * @num_fields: Number of register fields.
+ *
+ * The return value will be an -ENOMEM on error or zero for success.
+ * Newly allocated regmap_fields will be automatically freed by the
+ * device management code.
+ */
+int devm_regmap_field_bulk_alloc(struct device *dev,
+				 struct regmap *regmap,
+				 struct regmap_field **rm_field,
+				 struct reg_field *reg_field,
+				 int num_fields)
+{
+	struct regmap_field *rf;
+	int i;
+
+	rf = devm_kcalloc(dev, num_fields, sizeof(*rf), GFP_KERNEL);
+	if (!rf)
+		return -ENOMEM;
+
+	for (i = 0; i < num_fields; i++) {
+		regmap_field_init(&rf[i], regmap, reg_field[i]);
+		rm_field[i] = &rf[i];
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_regmap_field_bulk_alloc);
+
+/**
+ * regmap_field_bulk_free() - Free register field allocated using
+ *                       regmap_field_bulk_alloc.
+ *
+ * @field: regmap fields which should be freed.
+ */
+void regmap_field_bulk_free(struct regmap_field *field)
+{
+	kfree(field);
+}
+EXPORT_SYMBOL_GPL(regmap_field_bulk_free);
+
+/**
+ * devm_regmap_field_bulk_free() - Free a bulk register field allocated using
+ *                            devm_regmap_field_bulk_alloc.
+ *
+ * @dev: Device that will be interacted with
+ * @field: regmap field which should be freed.
+ *
+ * Free register field allocated using devm_regmap_field_bulk_alloc(). Usually
+ * drivers need not call this function, as the memory allocated via devm
+ * will be freed as per device-driver life-cycle.
+ */
+void devm_regmap_field_bulk_free(struct device *dev,
+				 struct regmap_field *field)
+{
+	devm_kfree(dev, field);
+}
+EXPORT_SYMBOL_GPL(devm_regmap_field_bulk_free);
+
 /**
  * devm_regmap_field_free() - Free a register field allocated using
  *                            devm_regmap_field_alloc.

include/linux/regmap.h

@@ -1150,6 +1150,17 @@ struct regmap_field *devm_regmap_field_alloc(struct device *dev,
 		struct regmap *regmap, struct reg_field reg_field);
 void devm_regmap_field_free(struct device *dev,	struct regmap_field *field);
 
+int regmap_field_bulk_alloc(struct regmap *regmap,
+			     struct regmap_field **rm_field,
+			     struct reg_field *reg_field,
+			     int num_fields);
+void regmap_field_bulk_free(struct regmap_field *field);
+int devm_regmap_field_bulk_alloc(struct device *dev, struct regmap *regmap,
+				 struct regmap_field **field,
+				 struct reg_field *reg_field, int num_fields);
+void devm_regmap_field_bulk_free(struct device *dev,
+				 struct regmap_field *field);
+
 int regmap_field_read(struct regmap_field *field, unsigned int *val);
 int regmap_field_update_bits_base(struct regmap_field *field,
 				  unsigned int mask, unsigned int val,