[LinuxPPS] Multiple device tree pps-gpio overlays?

[tom burkart]

Hi Frank,
I have done a bit more research on this and the file below should be  
all you need...
Use in your config.txt:

dtoverlay=pps-gpio,gpiopin=18,gpiopin1=17

The attached file needs to be put in the /boot/overlays directory.
Please make sure you save the original pps-gpio.dtbo

To use only one PPS pin you can use an invalid gpio pin for the second  
one or even -1.  This will produce an error message and disables the  
second one.

You should be able to use:

dtoverlay=pps-gpio

as GPIO18 and GPIO17 are the defaults

I believe there is a still better way of doing this but I am still not  
conversant enough with the device tree parlance.  I have attached the  
compiled pps-gpio as well as the source so anyone can experiment.

Kind regards,

Tom


Quoting Frank Wayne <fwayne at frankwayne.com>:

> Much appreciated. When I get back home next month, I hope to have  
> some time to test this.
>
> -----Original Message-----
> From: discussions-bounces at linuxpps.org  
> <discussions-bounces at linuxpps.org> On Behalf Of tom burkart
> Sent: Sunday, 06 May, 2018 04:55
> To: discussions at linuxpps.org
> Subject: Re: [LinuxPPS] Multiple device tree pps-gpio overlays?
>
> Hi,
> just replying to an old post (Oct 2017):
>
>> I am trying to create two PPS devices on a Raspberry Pi 3 running
>> Raspbian (Stretch). My config.txt contains:
>> dtoverlay=pps-gpio,gpiopin=17
>> dtoverlay=pps-gpio,gpiopin=18
>> This creates only a single PPS sevice: /dev/pps0. How do I get two (or
>> more) devices?
>
> I have a running RPI with PPS on pin 18 that works quite well.
> What you are doing requires a second pps-gpio.dtbo with some labels  
> changed so that it works as a second PPS input.
>
> I have attached a modified dtbo file together with its source file  
> so you can experiment yourself.  These are untested and may need  
> further modifications before it works.  BTW, "dtc" is the command to  
> convert between the two.

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