Can't enable PPS on AGX Xavier

你好,我现在在agx xavier使能pps驱动,系统版本是35.1.0,做法如下:

  1. 在tegra194-p2888-0000-a00.dtsi中加入pps模块:
    pps {
    //here use gpio for the pin in which you want pps signal.
    gpios = <&tegra_main_gpio TEGRA194_MAIN_GPIO(A, 0) GPIO_ACTIVE_LOW>;
    compatible = “pps-gpio”;
    assert-falling-edge;
    status = “okay”;
    };
  2. 修改了pps-gpio.c(line 189 return -EINVAL 改为 return ret)
    然后运行./nvbuild.sh -o $PWD/kernel_out 编译出tegra194-p2888-0001-p2822-0000.dtb 和 Image,然后刷到Xavier中,发现可以在dmesg中看到pps0,设备,但是还是会有报错,kernel log如下:
    [ 0.447522] pps_core: LinuxPPS API ver. 1 registered
    [ 0.447531] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti giometti@linux.it
    [ 2.973651] pps-gpio pps: failed to request PPS GPIO
    [ 5.771731] pps_core: source pps.-1 got cdev (246:0)
    [ 5.771750] pps pps0: new PPS source pps.-1
    [ 5.775693] pps pps0: Registered IRQ 284 as PPS source
    并且接入pps信号利用ppstest 工具去看还是有问题,无法正常解析。
    可以帮我看下是什么问题吗?

please see-also HOW to Increase GNNS timing module on Xavier? - #9 by shgarg, thanks

我按照这个文档上的内容去操作,现在已经不能开机了。。。
重刷系统后也无法回到之前有pps0设备的状态。。。

hello m18829573782,

may I know what’s the complete steps, and also the bootloader logs about the boot failure.

  1. 从官网下载源码:
    https://developer.nvidia.com/embedded/jetson-linux-r351
    下载的文件是: Driver Package (BSP) Sources

然后按照这个链接下面的说明进行操作:
https://docs.nvidia.com/jetson/archives/r34.1/DeveloperGuide/text/SD/Kernel/KernelCustomization.html

在进行编译前我在hardware/nvidia/platform/t19x/galen/kernel-dts/common/tegra194-p2888-0000-a00.dtsi这个文件中加入了pps node,以及在pps-gpio.c中进行了最上面的修改,然后执行./nvbuild.sh -o $PWD/kernel_out进行编译

after a long long time debuging, now it can worked!
my practice is as belows:

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