rtc: add dm_rtc_read helper and ->read method
Some users may want to read multiple consecutive 8-bit
registers. Instead of each caller having to implement the loop,
provide a dm_rtc_read() helper. Also, allow a driver to provide a
->read method, which can be more efficient than reading one register
at a time.
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
diff --git a/drivers/rtc/rtc-uclass.c b/drivers/rtc/rtc-uclass.c
index 926cca2..4a0e3c5 100644
--- a/drivers/rtc/rtc-uclass.c
+++ b/drivers/rtc/rtc-uclass.c
@@ -40,6 +40,25 @@
return ops->reset(dev);
}
+int dm_rtc_read(struct udevice *dev, unsigned int reg, u8 *buf, unsigned int len)
+{
+ struct rtc_ops *ops = rtc_get_ops(dev);
+
+ assert(ops);
+ if (ops->read)
+ return ops->read(dev, reg, buf, len);
+ if (!ops->read8)
+ return -ENOSYS;
+ while (len--) {
+ int ret = ops->read8(dev, reg++);
+
+ if (ret < 0)
+ return ret;
+ *buf++ = 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 8aabfc1..f30e908 100644
--- a/include/rtc.h
+++ b/include/rtc.h
@@ -56,6 +56,18 @@
int (*reset)(struct udevice *dev);
/**
+ * read() - Read multiple 8-bit registers
+ *
+ * @dev: Device to read from
+ * @reg: First register to read
+ * @buf: Output buffer
+ * @len: Number of registers to read
+ * @return 0 if OK, -ve on error
+ */
+ int (*read)(struct udevice *dev, unsigned int reg,
+ u8 *buf, unsigned int len);
+
+ /**
* read8() - Read an 8-bit register
*
* @dev: Device to read from
@@ -110,6 +122,17 @@
int dm_rtc_reset(struct udevice *dev);
/**
+ * dm_rtc_read() - Read multiple 8-bit registers
+ *
+ * @dev: Device to read from
+ * @reg: First register to read
+ * @buf: Output buffer
+ * @len: Number of registers to read
+ * @return 0 if OK, -ve on error
+ */
+int dm_rtc_read(struct udevice *dev, unsigned int reg, u8 *buf, unsigned int len);
+
+/**
* rtc_read8() - Read an 8-bit register
*
* @dev: Device to read from