Add PPS pulse-width support

This series of five patches adds pulse-width calculation support to the pps core (patch 1)
It then enables pulse-width calculation for the pps-gpio driver (patches 2 - 5).

*) Pulse-width in measured in nano seconds.
*) Width time can be calculated for both assert-time and reset-time. *) New sysfs were added to expose the pulse-width.
*) Support was added to pps-gpio driver to enable capture-clear based on
device-tree.
*) Enabling pulse-width calculation for pps-gpio driver is done based on
new boolean device-tree properties.

Eliav Farber (5):
pps: add pulse-width calculation in nsec
dt-bindings: pps: pps-gpio: introduce capture-clear property
pps: clients: gpio: add option to set capture-clear from device-tree
dt-bindings: pps: pps-gpio: introduce pulse-width properties
pps: clients: gpio: enable pps pulse-width calculations based on
device-tree

 .../devicetree/bindings/pps/pps-gpio.txt      | 10 ++++
 drivers/pps/clients/pps-gpio.c                | 15 ++++++
 drivers/pps/kapi.c                            | 49 +++++++++++++++++++
 drivers/pps/pps.c                             |  9 ++++
 drivers/pps/sysfs.c                           | 30 ++++++++++++
 include/linux/pps_kernel.h                    |  3 ++
 include/uapi/linux/pps.h                      | 19 +++++++
 7 files changed, 135 insertions(+)

2.40.1