[PATCH v7 0/4] PPS: pps-gpio PPS ECHO implementation

[Tom Burkart <tom@aussec.com>]

Hi all,
please find attached the PPS-GPIO PPS ECHO implementation patch. The
driver claims to have echo functionality in the sysfs interface but this
functionality is not present.  This patch provides this functionality.

Parts 1 and 2 of the patch change the original driver from the number
based GPIO ABI to the descriptor based ABI.  This has been modified
to not break backward compatibility.

Parts 3 and 4 then add the PPS ECHO functionality.  This is enabled if a
"echo-gpios" entry is found in the devicetree.

Changes in v4:
There is a bugfix in part 2 that was returning an uninitialised variable
and juggling some code that speeds up the probe by not running code when
not using PPS ECHO.

Changes in v5:
Meet all requirements of checkpatch

Changes in v6:
Cosmetic changes to code layout

Changes in v7:
Also accept the DEPRECATED "gpios" devicetree entry to ensure backward
compatibility.

On the linuxpps mailing list it was suggested to use a hrtimer for
resetting the GPIO ECHO active state to the inactive state.
Please also comment on whether a hrtimer is necessary/desirable for the
purpose of resetting the echo pin active state.  I am happy to implement
it if there is a need.

Please install, test and comment as it is now a quite major change to
the driver.
Please do send suggestions for improvement.

Tom Burkart

Tom Burkart (4):
  dt-bindings: pps: descriptor-based gpio, capture-clear addition
  pps: descriptor-based gpio, capture-clear addition
  dt-bindings: pps: pps-gpio PPS ECHO implementation
  pps: pps-gpio pps-echo implementation

 Documentation/devicetree/bindings/pps/pps-gpio.txt |  17 +-
 drivers/pps/clients/pps-gpio.c                     | 225 +++++++++++++++++----
 include/linux/pps-gpio.h                           |   6 +-
 3 files changed, 203 insertions(+), 45 deletions(-)

-- 
2.12.3