Ppstest time_pps_fetch() error -1 (Connection timed out)

[252830387]

Hi,

agx orin jp5.1.1 Self-defined board自定板子

ppstest /dev/pps0
→

trying PPS source "/dev/pps0"
found PPS source "/dev/pps0"
ok, found 1 source(s), now start fetching data...
source 0 - assert 1698848726.442950344, sequence: 19191 - clear  0.000000000, sequence: 0

ppstest /dev/pps1
→

trying PPS source "/dev/pps1"
found PPS source "/dev/pps1"
ok, found 1 source(s), now start fetching data...
time_pps_fetch() error -1 (Connection timed out)

However, the PPS interrupt can be acquired and the counter increments, indicating that the system has successfully obtained the interrupt.
但是中断能获取到pps中断，并且会递增，说明系统已经获取到中断：

Here is the patch for PPS modification:
如下是pps修改的补丁：

diff --git a/Linux_for_Tegra/source/hardware/nvidia/platform/t23x/concord/kernel-dts/tegra234-p3701-0004-p3737-0000.dts b/Linux_for_Tegra/source/hardware/nvidia/platform/t23x/concord/kernel-dts/tegra234-p3701-0004-p3737-0000.dts
index 132fd345c..3d8e4e270 100644
--- a/Linux_for_Tegra/source/hardware/nvidia/platform/t23x/concord/kernel-dts/tegra234-p3701-0004-p3737-0000.dts
+++ b/Linux_for_Tegra/source/hardware/nvidia/platform/t23x/concord/kernel-dts/tegra234-p3701-0004-p3737-0000.dts
@@ -68,6 +68,13 @@
 		status = "okay";
 	};
 
+	pps {
+		gpios = <&tegra_main_gpio TEGRA234_MAIN_GPIO(Q, 2) GPIO_ACTIVE_LOW>;
+		compatible = "pps-gpio";
+		assert-falling-edge;
+		status = "okay";
+	};
+
 	bpmp {
 		i2c {
 			tegra_tmp451: temp-sensor@4c {
diff --git a/Linux_for_Tegra/source/kernel/kernel-5.10/arch/arm64/configs/defconfig b/Linux_for_Tegra/source/kernel/kernel-5.10/arch/arm64/configs/defconfig
index c8a215f95..5421a7e1c 100644
--- a/Linux_for_Tegra/source/kernel/kernel-5.10/arch/arm64/configs/defconfig
+++ b/Linux_for_Tegra/source/kernel/kernel-5.10/arch/arm64/configs/defconfig
@@ -754,8 +754,11 @@ CONFIG_SPI_ZYNQMP_GQSPI=m
 CONFIG_SPI_SPIDEV=m
 CONFIG_SPI_TLE62X0=m
 CONFIG_SPMI=m
+CONFIG_PPS=y
 CONFIG_PPS_DEBUG=y
-CONFIG_PPS_CLIENT_GPIO=y
+CONFIG_PPS_CLIENT_KTIMER=y
+CONFIG_PPS_CLIENT_LDISC=y
+CONFIG_PPS_CLIENT_GPIO=m
 CONFIG_PINCTRL_TEGRA186_DPAUX=y
 CONFIG_PINCTRL_TEGRA234_DPAUX=y
 CONFIG_PINCTRL_SINGLE=y
-- 

Please help check why ppstest /dev/pps1 is reporting an error. Thank you.

帮忙看一下为什么ppstest /dev/pps1会报错，谢谢

[JerryChang]

hello 252830387,

according to your code snippets, it’s assert on the falling-edge of signal.

@252830387

+	pps {
+		gpios = <&tegra_main_gpio TEGRA234_MAIN_GPIO(Q, 2) GPIO_ACTIVE_LOW>;
+		compatible = "pps-gpio";
+		assert-falling-edge;

since it shows connection has timed out.
may I know what’s your hardware setups? did you have continuous PPS signal attached?

besides,
you may see-also developer guide, Using the Pins in GPIO Mode to double check you’re using correct pin.

[252830387]

GPIO_ACTIVE_LOW ->GPIO_ACTIVE_HIGH