dm: pmic: Add functions to adjust PMIC registers

It is a common requirement to update some PMIC registers. Provide some
simple convenience functions to do this.

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

drivers/power/pmic/pmic-uclass.c

@@ -139,6 +139,38 @@ int pmic_write(struct udevice *dev, uint reg, const uint8_t *buffer, int len)
 	return ops->write(dev, reg, buffer, len);
 }
 
+int pmic_reg_read(struct udevice *dev, uint reg)
+{
+	u8 byte;
+	int ret;
+
+	ret = pmic_read(dev, reg, &byte, 1);
+	debug("%s: reg=%x, value=%x\n", __func__, reg, byte);
+
+	return ret ? ret : byte;
+}
+
+int pmic_reg_write(struct udevice *dev, uint reg, uint value)
+{
+	u8 byte = value;
+
+	debug("%s: reg=%x, value=%x\n", __func__, reg, value);
+	return pmic_read(dev, reg, &byte, 1);
+}
+
+int pmic_clrsetbits(struct udevice *dev, uint reg, uint clr, uint set)
+{
+	u8 byte;
+	int ret;
+
+	ret = pmic_reg_read(dev, reg);
+	if (ret < 0)
+		return ret;
+	byte = (ret & ~clr) | set;
+
+	return pmic_reg_write(dev, reg, byte);
+}
+
 UCLASS_DRIVER(pmic) = {
 	.id		= UCLASS_PMIC,
 	.name		= "pmic",

include/power/pmic.h

@@ -264,6 +264,40 @@ int pmic_reg_count(struct udevice *dev);
  */
 int pmic_read(struct udevice *dev, uint reg, uint8_t *buffer, int len);
 int pmic_write(struct udevice *dev, uint reg, const uint8_t *buffer, int len);
+
+/**
+ * pmic_reg_read() - read a PMIC register value
+ *
+ * @dev:	PMIC device to read
+ * @reg:	Register to read
+ * @return value read on success or negative value of errno.
+ */
+int pmic_reg_read(struct udevice *dev, uint reg);
+
+/**
+ * pmic_reg_write() - write a PMIC register value
+ *
+ * @dev:	PMIC device to write
+ * @reg:	Register to write
+ * @value:	Value to write
+ * @return 0 on success or negative value of errno.
+ */
+int pmic_reg_write(struct udevice *dev, uint reg, uint value);
+
+/**
+ * pmic_clrsetbits() - clear and set bits in a PMIC register
+ *
+ * This reads a register, optionally clears some bits, optionally sets some
+ * bits, then writes the register.
+ *
+ * @dev:	PMIC device to update
+ * @reg:	Register to update
+ * @clr:	Bit mask to clear (set those bits that you want cleared)
+ * @set:	Bit mask to set (set those bits that you want set)
+ * @return 0 on success or negative value of errno.
+ */
+int pmic_clrsetbits(struct udevice *dev, uint reg, uint clr, uint set);
+
 #endif /* CONFIG_DM_PMIC */
 
 #ifdef CONFIG_POWER