add commandline tool to check rtc battery status #438

nhahnetsrot · 2023-05-04T08:09:56Z

The patch adds the readrtcbattery commandline tool that prints the current status of the rtc battery (1 == faulty, 0 == ok).

Signed-off-by: Torsten Hahn <[email protected]>

recipes-app/read-rtc-battery/files/src/readrtcbattery.c

jan-kiszka · 2023-05-04T08:12:03Z

recipes-app/read-rtc-battery/files/src/CMakeLists.txt

@@ -0,0 +1,7 @@
+cmake_minimum_required(VERSION 3.2)


Missing copyright header.

jan-kiszka · 2023-05-04T08:14:01Z

recipes-app/read-rtc-battery/files/src/readrtcbattery.c

+    }
+        // Close driver
+        printf("Closing Driver\n");
+        close(fd);


Inconsistent indention

jan-kiszka · 2023-05-04T08:14:29Z

recipes-app/read-rtc-battery/files/src/readrtcbattery.c

+
+    // 2nd step: Display error in command line if the device
+    // file wasn't found and close application
+    if(fd < 0) {


if is not a function, therefore if (...

jan-kiszka · 2023-05-04T08:14:46Z

recipes-app/read-rtc-battery/files/src/readrtcbattery.c

+    int retval = 0; // Return value of ioctl function (-1 = Error)
+
+    // 1st step: Open Driver
+    printf("\nOpening Driver\n");


Too verbose

removed printf statement

jan-kiszka · 2023-05-04T08:14:58Z

recipes-app/read-rtc-battery/files/src/readrtcbattery.c

+
+
+    // 3rd step: Read out 
+    printf("Process ioctl access to read battery status\n");


removed print statement

jan-kiszka · 2023-05-04T08:16:53Z

Commit message should always contain a reason WHY we want this change.

We may also think about who to make this tool discoverable to our users.

Another improvement could be calling this tool from a systemd timer once a week or so and log a system error if a low battery is detected.

Signed-off-by: Torsten Hahn <[email protected]>

nhahnetsrot · 2023-05-04T12:57:33Z

Commit message should always contain a reason WHY we want this change.

Ok, i added this

We may also think about who to make this tool discoverable to our users.

What do you mean with that ?

Another improvement could be calling this tool from a systemd timer once a week or so and log a system error if a low battery is detected.

Yes, sounds like a good idea ... shall i do that (ask Volker about that)?
My information was, that somehow this tool is intended to be called from some orcla module and then the battery-warning may show up in some high-level tool / health-gui.

jan-kiszka · 2023-05-04T13:01:02Z

General remark: Please fold changes to the patches into the existing ones (interactive rebase), rather than patching on top.

jan-kiszka · 2023-05-04T13:17:32Z

We may also think about who to make this tool discoverable to our users.

What do you mean with that ?

Having it mentioned in the README e.g.

Another improvement could be calling this tool from a systemd timer once a week or so and log a system error if a low battery is detected.

Yes, sounds like a good idea ... shall i do that (ask Volker about that)? My information was, that somehow this tool is intended to be called from some orcla module and then the battery-warning may show up in some high-level tool / health-gui.

We don't have those tools included here. This layer is supposed to be free-standing first of all, providing guidance / examples / re-usable bits how to make use of the hardware.

BaochengSu · 2023-05-05T01:40:21Z

recipes-app/read-rtc-battery/files/src/readrtcbattery.c

@@ -0,0 +1,54 @@
+/**
+* Copyright (c) Siemens AG, 2019-2023


Better to use 2023 only

BaochengSu · 2023-05-05T01:51:07Z

recipes-app/read-rtc-battery/files/src/CMakeLists.txt

@@ -0,0 +1,15 @@
+#
+# Copyright (c) Siemens AG, 2019-2023


BaochengSu · 2023-05-05T01:53:30Z

recipes-app/read-rtc-battery/files/src/readrtcbattery.c

+    int fd; // Device file path
+    int batteryStatus; // Status of battery 
+    int retval = 0; // Return value of ioctl function (-1 = Error)
+
+    // 1st step: Open Driver
+    fd = open("/dev/rtc", O_RDONLY);
+
+    // 2nd step: Display error in command line if the device
+    // file wasn't found and close application
+    if (fd < 0) {
+        printf("Device file not found\n");
+        return EXIT_FAILURE;
+    }
+
+    // 3rd step: Read out 
+    retval = ioctl(fd, RTC_VL_DATA_INVALID, &batteryStatus);
+
+    if (retval == -1) {
+        // 4th step: Display error in command line if the ioctl function isn't able to access 
+        // the specific function
+        printf("Error access ioctl function \n");
+        return EXIT_FAILURE; 
+    } else {
+        // 5th step: Print battery status
+        printf("Battery status (1 = Error) %d\n", batteryStatus);
+    }
+    close(fd);
+
+    return EXIT_SUCCESS;
+} // main


This code is simple and straight-forward enough to be self-explained, so most of the comments are unnecessary.

BaochengSu · 2023-05-05T01:54:36Z

recipes-app/read-rtc-battery/files/src/readrtcbattery.c

+        // 4th step: Display error in command line if the ioctl function isn't able to access 
+        // the specific function
+        printf("Error access ioctl function \n");
+        return EXIT_FAILURE; 


close(fd) before return error.

AsuraZeng · 2023-05-05T01:56:16Z

hi

If no battery or voltage is low, using the existing tool hwclock also can show the status.

hwclock 
[  107.495137] rtc-pcf8563 2-0051: low voltage detected, date/time is not reliable.
hwclock: ioctl(RTC_RD_TIME) to /dev/rtc0 to read the time failed: Invalid argument

BaochengSu · 2023-05-05T02:06:29Z

recipes-core/images/iot2050-image-example.bb

@@ -45,6 +45,7 @@ IMAGE_INSTALL += " \
    libteec1 \
    optee-client-dev \
    tee-supplicant \
+    read-rtc-battery \


How to test it?

BaochengSu · 2023-05-05T05:12:01Z

recipes-app/read-rtc-battery/files/src/readrtcbattery.c

+    } else {
+        // 5th step: Print battery status
+        printf("Battery status (1 = Error) %d\n", batteryStatus);
+    }


No need to wrap this print to the else branch, since the return in if.

jan-kiszka · 2023-05-06T06:53:43Z

hi

If no battery or voltage is low, using the existing tool hwclock also can show the status.
hwclock 
[  107.495137] rtc-pcf8563 2-0051: low voltage detected, date/time is not reliable.
hwclock: ioctl(RTC_RD_TIME) to /dev/rtc0 to read the time failed: Invalid argument

hwclock is apparently not using RTC_VL_READ while only that IOCTL is triggering the readout of the RTC status bit we need.

jan-kiszka · 2023-05-06T06:54:45Z

recipes-app/read-rtc-battery/files/src/readrtcbattery.c

+    }
+
+    // 3rd step: Read out 
+    retval = ioctl(fd, RTC_VL_DATA_INVALID, &batteryStatus);


This is not correct, please read https://support.industry.siemens.com/forum/de/en/posts/check-rtc-battery-status-of-iot2050/291926 again.

jan-kiszka · 2023-06-09T21:23:03Z

A customer analyzed a problem with the current implementation of RTC_VL_READ in our RTC driver: Every write clears the INVALID bit, and that prevents checking the state after, e.g., a write-back done on NTP adjustment during boot. Unfortunately, he didn't report his findings to the upstream kernel.

So I'm trying to resolve that there, see https://lore.kernel.org/lkml/[email protected]/T/#u. A simple python script to read the ioctl proved it's working on our hardware.

jan-kiszka · 2023-10-13T06:12:25Z

Seems the hardware does not permit proper read-out, and the kernel does not allow working around that limitation. I'm not sure if it still makes sense to follow this path, given that Linux has no framework to report the battery state via some userspace service. Users could still evaluate the system boot log for warnings about the battery state.

add commandline tool to check rtc battery status

91fa1c2

Signed-off-by: Torsten Hahn <[email protected]>

jan-kiszka reviewed May 4, 2023

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recipes-app/read-rtc-battery/files/src/readrtcbattery.c Outdated Show resolved Hide resolved

jan-kiszka reviewed May 4, 2023

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corrected some typos, indentation and return codes

7be53b8

Signed-off-by: Torsten Hahn <[email protected]>

Removed some too-detailed log output.

b8c8163

BaochengSu reviewed May 5, 2023

View reviewed changes

recipes-app/read-rtc-battery/files/src/CMakeLists.txt

@@ -0,0 +1,15 @@

#

# Copyright (c) Siemens AG, 2019-2023

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Same here

BaochengSu reviewed May 5, 2023

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add commandline tool to check rtc battery status #438

add commandline tool to check rtc battery status #438

nhahnetsrot commented May 4, 2023

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jan-kiszka commented Jun 9, 2023

jan-kiszka commented Oct 13, 2023



		// 3rd step: Read out
		printf("Process ioctl access to read battery status\n");

add commandline tool to check rtc battery status #438

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add commandline tool to check rtc battery status #438

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nhahnetsrot commented May 4, 2023

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jan-kiszka commented May 4, 2023

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