diff --git a/patch/kernel/sunxi-next/rtc-sunxi-clocksource.patch b/patch/kernel/sunxi-next/rtc-sunxi-clocksource.patch
new file mode 100644
index 0000000000..e69d793119
--- /dev/null
+++ b/patch/kernel/sunxi-next/rtc-sunxi-clocksource.patch
@@ -0,0 +1,121 @@
+
+This adds a sysfs 'clock_source' attribute which can be used to query
+and set the clock source of the RTC, either 'internal' or 'external'.
+
+Important note: Probing the pins of the 32kHz crystal with a scope will
+not reliably tell you whether the (usually) more accurate external is
+selected! On a 'Cubietech Cubietruck' board, the author saw a stable
+32768Hz signal on the crystal, even though the internal oscillator was
+selected and the clock wildly drifting.
+
+Using adjtimex might help to figure out which oscillator is selected:
+
+~# echo internal > /sys/devices/.../1c20d00.rtc/clock_source
+~# adjtimex -n -c=3
+                                      --- current ---   -- suggested --
+cmos time     system-cmos  error_ppm   tick      freq    tick      freq
+1469627826      31.224561
+1469627835      31.858098    63353.6  10000         0
+1469627844      32.490782    63268.4  10000         0    9367   2069425
+~# echo external > /sys/devices/.../1c20d00.rtc/clock_source
+~# adjtimex -n -c=3
+                                      --- current ---   -- suggested --
+cmos time     system-cmos  error_ppm   tick      freq    tick      freq
+1469627851      32.883407
+1469627861      32.883380       -2.7  10000         0
+1469627871      32.883352       -2.8  10000         0   10000    185937
+
+Signed-off-by: Onno Kortmann <on...@gmx.net>
+---
+ drivers/rtc/rtc-sunxi.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 54 insertions(+)
+
+diff --git a/drivers/rtc/rtc-sunxi.c b/drivers/rtc/rtc-sunxi.c
+index abada60..3fcf571 100644
+--- a/drivers/rtc/rtc-sunxi.c
++++ b/drivers/rtc/rtc-sunxi.c
+@@ -36,6 +36,8 @@
+ #define SUNXI_LOSC_CTRL				0x0000
+ #define SUNXI_LOSC_CTRL_RTC_HMS_ACC		BIT(8)
+ #define SUNXI_LOSC_CTRL_RTC_YMD_ACC		BIT(7)
++#define SUNXI_LOSC_OSC32K_SRC_SEL 		BIT(0)
++#define SUNXI_LOSC_KEY_VALUE			0x16aa0000
+ 
+ #define SUNXI_RTC_YMD				0x0004
+ 
+@@ -432,6 +434,50 @@ static const struct of_device_id sunxi_rtc_dt_ids[] = {
+ };
+ MODULE_DEVICE_TABLE(of, sunxi_rtc_dt_ids);
+ 
++/* As per page 126 of the A20 manual, the lowest bit in LOSC_CTRL_REG controls
++ * the 32.768KHz clock source to use for the RTC. Using the clock_source sysfs
++ * attribute, the clock can be selected between external (accurate 32kHz
++ * crystal) and internal (seems to be an inaccurate RC oscillator) mode.  It
++ * appears that this bit is non-volatile and will be kept in the RTC when the
++ * system is powered off.
++ */
++static ssize_t sunxi_rtc_show_clock_source(struct device *dev,
++					struct device_attribute *attr,
++					char *buf)
++{
++	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
++	u32 val = readl(chip->base + SUNXI_LOSC_CTRL);
++	if (val & SUNXI_LOSC_OSC32K_SRC_SEL)
++		return sprintf(buf, "internal [external]\n");
++	else
++		return sprintf(buf, "[internal] external\n");
++}
++
++static ssize_t sunxi_rtc_store_clock_source(struct device *dev,
++					struct device_attribute *attr,
++					const char *buf, size_t count) {
++	struct sunxi_rtc_dev *chip = dev_get_drvdata(dev);
++	u32 val = readl(chip->base + SUNXI_LOSC_CTRL);
++
++	if (strncmp(buf, "external", 8) == 0)
++		val|=SUNXI_LOSC_OSC32K_SRC_SEL;
++	else if (strncmp(buf, "internal", 8) == 0)
++		val&=~SUNXI_LOSC_OSC32K_SRC_SEL;
++	else
++		return -EINVAL;
++
++        /* Writing this bit requires setting the upper 16 bit to 0x16aa (key
++	 * value). */
++	val |= SUNXI_LOSC_KEY_VALUE;
++
++	writel(val, chip->base + SUNXI_LOSC_CTRL);
++	return count;
++}
++
++static DEVICE_ATTR(clock_source, S_IRUGO | S_IWUSR,
++		sunxi_rtc_show_clock_source,
++		sunxi_rtc_store_clock_source);
++
+ static int sunxi_rtc_probe(struct platform_device *pdev)
+ {
+ 	struct sunxi_rtc_dev *chip;
+@@ -490,6 +536,13 @@ static int sunxi_rtc_probe(struct platform_device *pdev)
+ 
+ 	dev_info(&pdev->dev, "RTC enabled\n");
+ 
++	ret = device_create_file(&pdev->dev, &dev_attr_clock_source);
++	if (ret) {
++		dev_err(&pdev->dev, "Unable to create sysfs entry: %s\n",
++			dev_attr_clock_source.attr.name);
++		return ret;
++	}
++
+ 	return 0;
+ }
+ 
+@@ -499,6 +552,7 @@ static int sunxi_rtc_remove(struct platform_device *pdev)
+ 
+ 	rtc_device_unregister(chip->rtc);
+ 
++	device_remove_file(&pdev->dev, &dev_attr_clock_source);
+ 	return 0;
+ }
+ 
+-- 
+2.2.0.34.gb8f29bf
+