Patch "rtc: sun6i: Switch to the external oscillator" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

rtc: sun6i: Switch to the external oscillator

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
rtc-sun6i-switch-to-the-external-oscillator.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Maxime Ripard <[email protected]>
Date: Mon, 23 Jan 2017 11:41:48 +0100
Subject: rtc: sun6i: Switch to the external oscillator

From: Maxime Ripard <[email protected]>

commit fb61bb82cb46a932ef2fc62e1c731c8e7e6640d5 upstream.

The RTC is clocked from either an internal, imprecise, oscillator or an external one, which is usually much more accurate.

The difference perceived between the time elapsed and the time reported by the RTC is in a 10% scale, which prevents the RTC from being useful at all.

Fortunately, the external oscillator is reported to be mandatory in the Allwinner datasheet, so we can just switch to it.

---
 drivers/rtc/rtc-sun6i.c |    6 ++++++
 1 file changed, 6 insertions(+)

@@ -37,9 +37,11 @@
 
 /* Control register */
 #define SUN6I_LOSC_CTRL				0x0000
+#define SUN6I_LOSC_CTRL_KEY			(0x16aa << 16)
 #define SUN6I_LOSC_CTRL_ALM_DHMS_ACC		BIT(9)
 #define SUN6I_LOSC_CTRL_RTC_HMS_ACC		BIT(8)
 #define SUN6I_LOSC_CTRL_RTC_YMD_ACC		BIT(7)
+#define SUN6I_LOSC_CTRL_EXT_OSC			BIT(0)
 #define SUN6I_LOSC_CTRL_ACC_MASK		GENMASK(9, 7)
 
 /* RTC */

@@ -417,6 +419,10 @@ static int sun6i_rtc_probe(struct platfo
 	/* disable alarm wakeup */
 	writel(0, chip->base + SUN6I_ALARM_CONFIG);
 
+	/* switch to the external, more precise, oscillator */
+	writel(SUN6I_LOSC_CTRL_KEY | SUN6I_LOSC_CTRL_EXT_OSC,
+	       chip->base + SUN6I_LOSC_CTRL);
+
 	chip->rtc = rtc_device_register("rtc-sun6i", &pdev->dev,
 					&sun6i_rtc_ops, THIS_MODULE);
 	if (IS_ERR(chip->rtc)) {

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/rtc-sun6i-add-some-locking.patch queue-4.4/rtc-sun6i-switch-to-the-external-oscillator.patch