lib/vsprintf: Print time and date in human readable format via %pt

There are users which print time and date represented by content of
struct rtc_time in human readable format.

Instead of open coding that each time introduce %ptR[dt][r] specifier.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

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
 ----------