DART-MX8M RTC: Difference between revisions

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--> {{PageHeader|{{#var:HARDWARE_NAME}} RTC}} {{DocImage|category1=Yocto|category2=DART-MX8M}}[[Category:DART-MX8M-MINI]] __toc__
--> {{#lst:B2QT_Platform_Customization|{{#var:RELEASE_PARAM}}}} <!--
--> {{PageHeader|{{#var:HARDWARE_NAME}} - Real Time Clock (RTC)}} {{DocImage|category1=Yocto|category2=Debian}}[[Category:DART-MX8M]][[Category:DART-MX8M-MINI]][[Category:DART-MX8M-PLUS]] __toc__
= Setting the RTC =
= Setting the RTC =
To set the RTC first set the date from Linux shell, type:
First set the system date & time:
  # date --set="20171231 23:59"
  # date --set="20171231 23:59"
Then set the real time clock from Linux shell, type:
Then set the HW RTC using the system date & time:
  # hwclock --systohc --utc
  # hwclock --systohc --utc
Power down your board wait 5 minutes and power up. Check your system with date and the time should be up to date.<br>
<br>
Power down your board, wait 5 minutes and power up again, then check you system date & time and verify it is correct:
# date


= Wake-up using the RTC =
= Wake-up using the RTC =
Wake-up using the RTC requires hardware connection of RTC IRQ pin to a SoC GPIO (on {{#var:HARDWARE_NAME}} carrier board this is GPIO1_15).<br>
Wake-up using the RTC requires hardware connection of RTC IRQ pin to a SoC GPIO.<br>
Configure your kernel and add relevant RTC driver. For {{#var:HARDWARE_NAME}} carrier this is Device Drivers -> Real Time Clock  -> <*> Dallas/Maxim DS1307/37/38/39/40, ST M41T00, EPSON RX-8025, ISL12057.<br>
On DART-MX8M, DART-MX8M-MINI and DART-MX8M-PLUS carrier boards RTC IRQ pin is connected to GPIO1_15.<br>
{{#ifeq: {{#var:HARDWARE_NAME}} | DART-MX8M |
On VAR-SOM-MX8M-MINI, VAR-SOM-MX8M-NANO VAR-SOM-MX8M-PLUS carrier boards RTC IRQ pin is not connected.<br>
Edit arch/arm64/boot/dts/{{#ifeq: {{#var:YOCTO_NAME}}|Morty|variscite/imx8m-var-dart-common.dtsi|freescale/fsl-imx8mq-var-dart-common.dtsi}} under Linux kernel source directory:
<pre>
&i2c2 {
...
rtc@0x68 {
status = "okay";
compatible = "dallas,ds1337";
reg = <0x68>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_rtc>;
interrupt-parent = <&gpio1>;
interrupts = <15 IRQ_TYPE_EDGE_FALLING>;
        };
        ...
};


&iomuxc {
== Using rtcwake command ==
...
imx8m-var-dart {
                ...
pinctrl_rtc: rtcgrp {
fsl,pins = <
MX8MQ_IOMUXC_GPIO1_IO15_GPIO1_IO15 0xc1
>;
};
                ...
};
</pre>
|
Edit arch/arm64/boot/dts/freescale/fsl-imx8mm-var-dart.dts under Linux kernel source directory:
<pre>
&i2c2 {
...
rtc@0x68 {
status = "okay";
compatible = "dallas,ds1337";
reg = <0x68>;
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_rtc>;
interrupt-parent = <&gpio1>;
interrupts = <15 IRQ_TYPE_EDGE_FALLING>;
        };
        ...
};
 
&iomuxc {
...
imx8mm-var-dart {
                ...
pinctrl_rtc: rtcgrp {
fsl,pins = <
MX8MM_IOMUXC_GPIO1_IO15_GPIO1_IO15 0x1c1
>;
};
                ...
};
</pre>
}}
Follow the "Build Linux from source code" guide to build the kernel and device trees and to copy them to your SD card. Don't forget to also build and install the kernel modules.<br>
For example, to set the RTC to wakeup after 10 seconds type:
For example, to set the RTC to wakeup after 10 seconds type:
  # echo enabled > /sys/class/rtc/rtc0/device/power/wakeup
  # echo enabled > /sys/class/rtc/rtc0/device/power/wakeup

Revision as of 02:58, 2 March 2021

DART-MX8M - Real Time Clock (RTC)

Setting the RTC

First set the system date & time:

# date --set="20171231 23:59"

Then set the HW RTC using the system date & time:

# hwclock --systohc --utc


Power down your board, wait 5 minutes and power up again, then check you system date & time and verify it is correct:

# date

Wake-up using the RTC

Wake-up using the RTC requires hardware connection of RTC IRQ pin to a SoC GPIO.
On DART-MX8M, DART-MX8M-MINI and DART-MX8M-PLUS carrier boards RTC IRQ pin is connected to GPIO1_15.
On VAR-SOM-MX8M-MINI, VAR-SOM-MX8M-NANO VAR-SOM-MX8M-PLUS carrier boards RTC IRQ pin is not connected.

Using rtcwake command

For example, to set the RTC to wakeup after 10 seconds type:

# echo enabled > /sys/class/rtc/rtc0/device/power/wakeup
# rtcwake -m mem -d rtc0 -s 10

For more options, like waking up at a specific time, run:

# rtcwake --help