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 926cca234e849bea544c111d0ae3b4e89320587e..4a0e3c5643dd62ad7c414ddd4139fa776baad19a 100644 (file)
--- a/drivers/rtc/rtc-uclass.c
+++ b/drivers/rtc/rtc-uclass.c
@@ -40,6 +40,25 @@ int dm_rtc_reset(struct udevice *dev)
        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 8aabfc1162a47a304efa53993cbffbd8a91ad0f0..f30e908221a280ed163a585cd0fa64a299d8eba6 100644 (file)
--- a/include/rtc.h
+++ b/include/rtc.h
@@ -55,6 +55,18 @@ struct rtc_ops {
         */
        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
         *
@@ -109,6 +121,17 @@ int dm_rtc_set(struct udevice *dev, struct rtc_time *time);
  */
 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
  *