[PATCH v2 02/10] rtc: add rtc_write() helper

[Rasmus Villemoes <rasmus.villemoes@prevas.dk>]

Similar to rtc_read(), introduce a helper that allows the caller to
write multiple consecutive 8-bit registers with one call. If the
driver provides the ->write method, use that, otherwise loop using
->write8.

Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
---
 drivers/rtc/rtc-uclass.c | 18 ++++++++++++++++++
 include/rtc.h            | 24 ++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/drivers/rtc/rtc-uclass.c b/drivers/rtc/rtc-uclass.c
index 44d76bb70f..cc5f9c7baa 100644
--- a/drivers/rtc/rtc-uclass.c
+++ b/drivers/rtc/rtc-uclass.c
@@ -57,6 +57,24 @@ int rtc_read(struct udevice *dev, unsigned int reg, u8 *buf, unsigned int len)
 	return 0;
 }
 
+int rtc_write(struct udevice *dev, unsigned int reg,
+	      const u8 *buf, unsigned int len)
+{
+	struct rtc_ops *ops = rtc_get_ops(dev);
+
+	assert(ops);
+	if (ops->write)
+		return ops->write(dev, reg, buf, len);
+	if (!ops->write8)
+		return -ENOSYS;
+	while (len--) {
+		int ret = ops->write8(dev, reg++, *buf++);
+		if (ret < 0)
+			return ret;
+	}
+	return 0;
+}
+
 int rtc_read8(struct udevice *dev, unsigned int reg)
 {
 	struct rtc_ops *ops = rtc_get_ops(dev);
diff --git a/include/rtc.h b/include/rtc.h
index 1c9c09fef8..8c66d37703 100644
--- a/include/rtc.h
+++ b/include/rtc.h
@@ -67,6 +67,18 @@ struct rtc_ops {
 	int (*read)(struct udevice *dev, unsigned int reg,
 			   u8 *buf, unsigned int len);
 
+	/**
+	 * write() - Write multiple 8-bit registers
+	 *
+	 * @dev:	Device to write to
+	 * @reg:	First register to write
+	 * @buf:	Input buffer
+	 * @len:	Number of registers to write
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*write)(struct udevice *dev, unsigned int reg,
+		     const u8 *buf, unsigned int len);
+
 	/**
 	 * read8() - Read an 8-bit register
 	 *
@@ -132,6 +144,18 @@ int dm_rtc_reset(struct udevice *dev);
  */
 int rtc_read(struct udevice *dev, unsigned int reg, u8 *buf, unsigned int len);
 
+/**
+ * rtc_write() - Write multiple 8-bit registers
+ *
+ * @dev:	Device to write to
+ * @reg:	First register to write
+ * @buf:	Input buffer
+ * @len:	Number of registers to write
+ * @return 0 if OK, -ve on error
+ */
+int rtc_write(struct udevice *dev, unsigned int reg,
+	      const u8 *buf, unsigned int len);
+
 /**
  * rtc_read8() - Read an 8-bit register
  *
-- 
2.23.0