[v3,00/10] new rtc methods, rtc command, and tests

I need access to registers other than just the timekeeping ones of the
pcf2127, so I wanted to implement ->read8 and ->write8. But for
testing these it appeared there was no convenient way to invoke those
from the shell, so I also ended up adding such a command.

Also, it seemed more natural to provide array variants that can read
or write several registers at once, so rtc_ops is expanded a bit.

Simon, I've taken the liberty of keeping your R-Bs despite the first
bullet below, yell if that's inappropriate.

Changes in v3:

- Call the functions dm_rtc_read/dm_rtc_write rather than just
  rtc_read/rtc_write, since the latter names are used for local
  helpers by a number of drivers. That also matches the existing
  dm_rtc_set/dm_rtc_get (though then not the existing
  rtc_read{8,16,32}).

- Update the rtc command (patch 6) as per Simon's feedback (parse
  input as hex, avoid overlong lines, use print_buffer()).
  
- Update the tests (patches 9 and 10) according to these changes.

Changes in v2:

- Use simply "read" and "write" instead of "read8_array",
  "write8_array", both for functions and methods, as suggested by
  Simon.

- The rtc command's interface has been simplified a bit (no separate
  read/readm; the number of arguments determines whether the user
  wants the result on the console or to a memory address)

- Add tests, both of rtc_{read,write}() and of the shell command,
  fixing a few things I stumbled on.

Rasmus Villemoes (10):
  rtc: add dm_rtc_read helper and ->read method
  rtc: add dm_rtc_write() helper
  rtc: fall back to ->{read,write} if ->{read,write}8 are not provided
  rtc: pcf2127: provide ->read method
  rtc: pcf2127: provide ->write method
  rtc: add rtc command
  rtc: sandbox-rtc: fix set method
  rtc: i2c_rtc_emul: catch any write to the "reset" register
  test: dm: rtc: add test of dm_rtc_read, dm_rtc_write
  test: dm: rtc: add tests of rtc shell command

 arch/sandbox/include/asm/rtc.h |   5 +
 cmd/Kconfig                    |   6 ++
 cmd/Makefile                   |   1 +
 cmd/rtc.c                      | 167 +++++++++++++++++++++++++++++++++
 drivers/rtc/i2c_rtc_emul.c     |   3 +-
 drivers/rtc/pcf2127.c          |  13 ++-
 drivers/rtc/rtc-uclass.c       |  56 ++++++++++-
 drivers/rtc/sandbox_rtc.c      |  65 +++++--------
 include/rtc.h                  |  47 ++++++++++
 test/dm/rtc.c                  | 118 ++++++++++++++++++++++-
 10 files changed, 431 insertions(+), 50 deletions(-)
 create mode 100644 cmd/rtc.c