This patch adds some examples about how to register a new PPS generator in the system, and how to manage it. Signed-off-by: Rodolfo Giometti <giometti@xxxxxxxxxxxx> --- Documentation/driver-api/pps.rst | 40 ++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/Documentation/driver-api/pps.rst b/Documentation/driver-api/pps.rst index 78dded03e5d8..c71b3b878e41 100644 --- a/Documentation/driver-api/pps.rst +++ b/Documentation/driver-api/pps.rst @@ -202,6 +202,46 @@ Sometimes one needs to be able not only to catch PPS signals but to produce them also. For example, running a distributed simulation, which requires computers' clock to be synchronized very tightly. +To do so the class pps-gen has been added. PPS generators can be +registered int the kernel by defining a struct pps_gen_source_info as +follows:: + + static struct pps_gen_source_info pps_gen_dummy_info = { + .name = "dummy", + .use_system_clock = true, + .get_time = pps_gen_dummy_get_time, + .enable = pps_gen_dummy_enable, + }; + +Where the use_system_clock states if the generator uses the system +clock to generate its pulses, or from a peripheral device +clock. Method get_time() is used to query the time stored into the +generator clock, while the method enable() is used to enable or +disable the PPS pulse generation. + +Then calling the function pps_gen_register_source() in your +initialization routine as follows a new generator is created into the +system:: + + pps_gen = pps_gen_register_source(&pps_gen_dummy_info); + +Generators SYSFS support +------------------------ + +If the SYSFS filesystem is enabled in the kernel it provides a new class:: + + $ ls /sys/class/pps-gen/ + pps-gen0/ pps-gen1/ pps-gen2/ + +Every directory is the ID of a PPS generator defined in the system and +inside you find several files:: + + $ ls -F /sys/class/pps-gen/pps-gen0/ + dev enable name power/ subsystem@ system time uevent + +To enable the PPS signal generation you can use the command below:: + + $ echo 1 > /sys/class/pps-gen/pps-gen0/enable Parallel port generator ------------------------ -- 2.34.1