Re: [RFC PATCH 7/9] net: dsa: hellcreek: Add PTP status LEDs

Hi Andrew,

On Thu Jun 18 2020, Andrew Lunn wrote:

On Thu, Jun 18, 2020 at 08:40:27AM +0200, Kurt Kanzenbach wrote:

quoted

The switch has two controllable I/Os which are usually connected to LEDs. This
is useful to immediately visually see the PTP status.

These provide two signals:

 * is_gm

   This LED can be activated if the current device is the grand master in that
   PTP domain.

 * sync_good

   This LED can be activated if the current device is in sync with the network
   time.

Expose these via the LED framework to be controlled via user space
e.g. linuxptp.

Hi Kurt

Is the hardware driving these signals at all? Or are these just
suggested names in the documentation? It would not be an issue to have
user space to configure them to use the heartbeat trigger, etc?

These are more like GPIOs. If a 1 is set into the register then the
hardware drives the signal to high. The names are from the
documentation:

 * sync_good: This signal indicates that the switch is in sync
 * is_gm:     This signal indicates that the switch is the grand master

However, these signals have to be set by user space. Most likely these
signals are connected to LEDs.

Thanks,
Kurt