Merge tag 'rtc-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

Pull RTC updates from Alexandre Belloni:
 "Subsystem:
   - new %ptR printk format
   - rename core files
   - allow registration of multiple nvmem devices

  New driver:
   - i.MX system controller RTC

  Driver updates:
   - abx80x: handle voltage ioctls, correct binding doc
   - m41t80: correct month in alarm reads
   - pcf85363: add pcf85263 support
   - pcf8523: properly handle battery low flag
   - s3c: limit alarm to one year in the future as ALMYEAR is broken
   - sun6i: rework clock output binding"

* tag 'rtc-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (54 commits)
  rtc: rename core files
  rtc: nvmem: fix possible use after free
  rtc: add i.MX system controller RTC support
  dt-bindings: fsl: scu: add rtc binding
  rtc: pcf2123: Add Microcrystal rv2123
  rtc: class: reimplement devm_rtc_device_register
  rtc: enforce rtc_timer_init private_data type
  rtc: abx80x: Implement RTC_VL_READ,CLR ioctls
  rtc: pcf85363: Add support for NXP pcf85263 rtc
  dt-bindings: rtc: pcf85363: Document pcf85263 real-time clock
  rtc: pcf8523: don't return invalid date when battery is low
  dt-bindings: rtc: use a generic node name for ds1307
  PM: Switch to use %ptR
  m68k/mac: Switch to use %ptR
  Input: hp_sdc_rtc - Switch to use %ptR
  rtc: tegra: Switch to use %ptR
  rtc: s5m: Switch to use %ptR
  rtc: s3c: Switch to use %ptR
  rtc: rx8025: Switch to use %ptR
  rtc: rx6110: Switch to use %ptR
  ...

1 files changed, 18 insertions, 0 deletions

diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst
index ff48b55040ef..a7fae4538946 100644
--- a/Documentation/core-api/printk-formats.rst
+++ b/Documentation/core-api/printk-formats.rst
@@ -412,6 +412,24 @@ Examples::
 
 Passed by reference.
 
+Time and date (struct rtc_time)
+-------------------------------
+
+::
+
+	%ptR		YYYY-mm-ddTHH:MM:SS
+	%ptRd		YYYY-mm-dd
+	%ptRt		HH:MM:SS
+	%ptR[dt][r]
+
+For printing date and time as represented by struct rtc_time structure in
+human readable format.
+
+By default year will be incremented by 1900 and month by 1. Use %ptRr (raw)
+to suppress this behaviour.
+
+Passed by reference.
+
 struct clk
 ----------