dm: pmic: code cleanup of PMIC uclass driver

The cleanup includes:
- pmic.h - fix mistakes in a few comments
- pmic operations: value 'reg_count' - redefine as function call
- fix function name: pmic_bind_childs() -> pmic_bind_children()
- pmic_bind_children: change the 'while' loop with the 'for'
- add implementation of pmic_reg_count() method
- pmic_bind_children() - update function call name
- Kconfig: add new line at the end of file
- Update MAX77686 driver code

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested on sandbox:
Tested-by: Simon Glass <sjg@chromium.org>

drivers/power/pmic/Kconfig

@@ -15,4 +15,4 @@ config DM_PMIC_MAX77686
 	depends on DM_PMIC
 	---help---
 	This config enables implementation of driver-model pmic uclass features
-	for PMIC MAX77686. The driver implements read/write operations.
+	for PMIC MAX77686. The driver implements read/write operations.

drivers/power/pmic/max77686.c

@@ -16,12 +16,17 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-static const struct pmic_child_info pmic_childs_info[] = {
+static const struct pmic_child_info pmic_children_info[] = {
 	{ .prefix = "ldo", .driver = MAX77686_LDO_DRIVER },
 	{ .prefix = "buck", .driver = MAX77686_BUCK_DRIVER },
 	{ },
 };
 
+static int max77686_reg_count(struct udevice *dev)
+{
+	return MAX77686_NUM_OF_REGS;
+}
+
 static int max77686_write(struct udevice *dev, uint reg, const uint8_t *buff,
 			  int len)
 {
@@ -47,7 +52,7 @@ static int max77686_bind(struct udevice *dev)
 {
 	int regulators_node;
 	const void *blob = gd->fdt_blob;
-	int childs;
+	int children;
 
 	regulators_node = fdt_subnode_offset(blob, dev->of_offset,
 					     "voltage-regulators");
@@ -59,8 +64,8 @@ static int max77686_bind(struct udevice *dev)
 
 	debug("%s: '%s' - found regulators subnode\n", __func__, dev->name);
 
-	childs = pmic_bind_childs(dev, regulators_node, pmic_childs_info);
-	if (!childs)
+	children = pmic_bind_children(dev, regulators_node, pmic_children_info);
+	if (!children)
 		debug("%s: %s - no child found\n", __func__, dev->name);
 
 	/* Always return success for this device */
@@ -68,7 +73,7 @@ static int max77686_bind(struct udevice *dev)
 }
 
 static struct dm_pmic_ops max77686_ops = {
-	.reg_count = MAX77686_NUM_OF_REGS,
+	.reg_count = max77686_reg_count,
 	.read = max77686_read,
 	.write = max77686_write,
 };

drivers/power/pmic/pmic-uclass.c

@@ -27,8 +27,8 @@ static ulong str_get_num(const char *ptr, const char *maxptr)
 	return simple_strtoul(ptr, NULL, 0);
 }
 
-int pmic_bind_childs(struct udevice *pmic, int offset,
-		     const struct pmic_child_info *child_info)
+int pmic_bind_children(struct udevice *pmic, int offset,
+		       const struct pmic_child_info *child_info)
 {
 	const struct pmic_child_info *info;
 	const void *blob = gd->fdt_blob;
@@ -53,14 +53,10 @@ int pmic_bind_childs(struct udevice *pmic, int offset,
 								 node);
 
 		child = NULL;
-		info = child_info;
-		while (info->prefix) {
+		for (info = child_info; info->prefix && info->driver; info++) {
 			prefix_len = strlen(info->prefix);
-			if (strncasecmp(info->prefix, node_name, prefix_len) ||
-			    !info->driver) {
-				info++;
+			if (strncasecmp(info->prefix, node_name, prefix_len))
 				continue;
-			}
 
 			debug("  - compatible prefix: '%s'\n", info->prefix);
 
@@ -110,16 +106,16 @@ int pmic_get(const char *name, struct udevice **devp)
 int pmic_reg_count(struct udevice *dev)
 {
 	const struct dm_pmic_ops *ops = dev_get_driver_ops(dev);
-	if (!ops)
+
+	if (!ops || !ops->reg_count)
 		return -ENOSYS;
 
-	return ops->reg_count;
+	return ops->reg_count(dev);
 }
 
 int pmic_read(struct udevice *dev, uint reg, uint8_t *buffer, int len)
 {
 	const struct dm_pmic_ops *ops = dev_get_driver_ops(dev);
-	int ret;
 
 	if (!buffer)
 		return -EFAULT;
@@ -127,17 +123,12 @@ int pmic_read(struct udevice *dev, uint reg, uint8_t *buffer, int len)
 	if (!ops || !ops->read)
 		return -ENOSYS;
 
-	ret = ops->read(dev, reg, buffer, len);
-	if (ret)
-		return ret;
-
-	return 0;
+	return ops->read(dev, reg, buffer, len);
 }
 
 int pmic_write(struct udevice *dev, uint reg, const uint8_t *buffer, int len)
 {
 	const struct dm_pmic_ops *ops = dev_get_driver_ops(dev);
-	int ret;
 
 	if (!buffer)
 		return -EFAULT;
@@ -145,11 +136,7 @@ int pmic_write(struct udevice *dev, uint reg, const uint8_t *buffer, int len)
 	if (!ops || !ops->write)
 		return -ENOSYS;
 
-	ret = ops->write(dev, reg, buffer, len);
-	if (ret)
-		return ret;
-
-	return 0;
+	return ops->write(dev, reg, buffer, len);
 }
 
 UCLASS_DRIVER(pmic) = {

include/power/pmic.h

@@ -11,9 +11,9 @@
 #ifndef __CORE_PMIC_H_
 #define __CORE_PMIC_H_
 
-#include <linux/list.h>
-#include <spi.h>
 #include <i2c.h>
+#include <spi.h>
+#include <linux/list.h>
 #include <power/power_chrg.h>
 
 enum { PMIC_I2C, PMIC_SPI, PMIC_NONE};
@@ -90,10 +90,10 @@ struct pmic {
  * U-Boot PMIC Framework
  * =====================
  *
- * UCLASS_PMIC - The is designed to provide an I/O interface for PMIC devices.
+ * UCLASS_PMIC - This is designed to provide an I/O interface for PMIC devices.
  *
  * For the multi-function PMIC devices, this can be used as parent I/O device
- * for each IC's interface. Then, each children uses its parent for read/write.
+ * for each IC's interface. Then, each child uses its parent for read/write.
  *
  * The driver model tree could look like this:
  *
@@ -112,8 +112,8 @@ struct pmic {
  * We can find two PMIC cases in boards design:
  * - single I/O interface
  * - multiple I/O interfaces
- * We bind single PMIC device for each interface, to provide an I/O as a parent,
- * of proper child devices. Each child usually implements a different function,
+ * We bind a single PMIC device for each interface, to provide an I/O for
+ * its child devices. And each child usually implements a different function,
  * controlled by the same interface.
  *
  * The binding should be done automatically. If device tree nodes/subnodes are
@@ -131,7 +131,7 @@ struct pmic {
  * Note:
  * Each PMIC interface driver should use a different compatible string.
  *
- * If each pmic child device driver need access the PMIC-specific registers,
+ * If a PMIC child device driver needs access the PMIC-specific registers,
  * it need know only the register address and the access can be done through
  * the parent pmic driver. Like in the example:
  *
@@ -141,10 +141,10 @@ struct pmic {
  * |   |_ dev: my_regulator (set value/etc..)  (is child)   - UCLASS_REGULATOR
  *
  * To ensure such device relationship, the pmic device driver should also bind
- * all its child devices, like in the example below. It should be done by call
- * the 'pmic_bind_childs()' - please refer to the description of this function
- * in this header file. This function, should be called in the driver's '.bind'
- * method.
+ * all its child devices, like in the example below. It can be done by calling
+ * the 'pmic_bind_children()' - please refer to the function description, which
+ * can be found in this header file. This function, should be called inside the
+ * driver's bind() method.
  *
  * For the example driver, please refer the MAX77686 driver:
  * - 'drivers/power/pmic/max77686.c'
@@ -156,18 +156,19 @@ struct pmic {
  * Should be implemented by UCLASS_PMIC device drivers. The standard
  * device operations provides the I/O interface for it's childs.
  *
- * @reg_count: devices register count
+ * @reg_count: device's register count
  * @read:      read 'len' bytes at "reg" and store it into the 'buffer'
  * @write:     write 'len' bytes from the 'buffer' to the register at 'reg' address
  */
 struct dm_pmic_ops {
-	int reg_count;
+	int (*reg_count)(struct udevice *dev);
 	int (*read)(struct udevice *dev, uint reg, uint8_t *buffer, int len);
 	int (*write)(struct udevice *dev, uint reg, const uint8_t *buffer,
 		     int len);
 };
 
-/* enum pmic_op_type - used for various pmic devices operation calls,
+/**
+ * enum pmic_op_type - used for various pmic devices operation calls,
  * for reduce a number of lines with the same code for read/write or get/set.
  *
  * @PMIC_OP_GET - get operation
@@ -181,7 +182,7 @@ enum pmic_op_type {
 /**
  * struct pmic_child_info - basic device's child info for bind child nodes with
  * the driver by the node name prefix and driver name. This is a helper struct
- * for function: pmic_bind_childs().
+ * for function: pmic_bind_children().
  *
  * @prefix - child node name prefix (or its name if is unique or single)
  * @driver - driver name for the sub-node with prefix
@@ -194,7 +195,7 @@ struct pmic_child_info {
 /* drivers/power/pmic-uclass.c */
 
 /**
- * pmic_bind_childs() - bind drivers for given parent pmic, using child info
+ * pmic_bind_children() - bind drivers for given parent pmic, using child info
  * found in 'child_info' array.
  *
  * @pmic       - pmic device - the parent of found child's
@@ -216,7 +217,7 @@ struct pmic_child_info {
  *     (pmic - bind automatically by compatible)
  *     compatible = "my_pmic";
  *     ...
- *     (pmic's childs - bind by pmic_bind_childs())
+ *     (pmic's childs - bind by pmic_bind_children())
  *     (nodes prefix: "ldo", driver: "my_regulator_ldo")
  *     ldo1 { ... };
  *     ldo2 { ... };
@@ -226,8 +227,8 @@ struct pmic_child_info {
  *     buck2 { ... };
  * };
  */
-int pmic_bind_childs(struct udevice *pmic, int offset,
-		     const struct pmic_child_info *child_info);
+int pmic_bind_children(struct udevice *pmic, int offset,
+		       const struct pmic_child_info *child_info);
 
 /**
  * pmic_get: get the pmic device using its name