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[FAQ] CCS/TDA4VM/J721e/J7200: How to enable RTC on Jacinto TDA4x EVM?

Part Number: TDA4VM

Tool/software: Code Composer Studio

MCP79410-I/SN is connected I2C0 interface of J721E SoC. How to enable the same?

  • Hi,

    Following changes are needed:

    J721e:/TDA4VM

    1. CONFIG enabling. The driver supporting MCP79410 RTC is drivers/rtc/rtc-ds1307.c.
      CONFIG_RTC_DRV_DS1307 needs to be enabled.

      Add CONFIG_RTC_DRV_DS1307=y to arch/arm64/configs/tisdk_j7-evm_defconfig under linux folder.

    2. DTS changes as below:

      diff --git a/arch/arm64/boot/dts/ti/k3-j721e-common-proc-board.dts b/arch/arm64/boot/dts/ti/k3-j721e-common-proc-board.dts
      index 6788a3611..9d642eb7a 100644
      --- a/arch/arm64/boot/dts/ti/k3-j721e-common-proc-board.dts
      +++ b/arch/arm64/boot/dts/ti/k3-j721e-common-proc-board.dts
      @@ -593,6 +593,11 @@
                      #gpio-cells = <2>;
              };
      
      +       rtc@6f {
      +               compatible = "microchip,mcp7941x";
      +               reg = <0x6f>;
      +       };
      +
              exp2: gpio@22 {
                      compatible = "ti,tca6424";
                      reg = <0x22>;
    3. Once you have made the changes in the defconfig & the dts files. All you need to do is:

      make linux

      then copy the kernel and DT binaries to your rootfs:

      cp $SDK_INSTALL_DIR:/board-support/linux*/arch/arm64/boot/Image $SDK_INSTALL_DIR:/board-support/linux*/arch/arm64/boot/dts/ti/k3-j721e-common-porc-board.dtb /media/$USER/rootfs/boot

      J7200:

      1. CONFIG enabling. The driver supporting MCP79410 RTC is drivers/rtc/rtc-ds1307.c.
        CONFIG_RTC_DRV_DS1307 needs to be enabled.

        Add CONFIG_RTC_DRV_DS1307=y to arch/arm64/configs/tisdk_j7200-evm_defconfig under linux folder.

      2. DTS changes as below:

        diff --git a/arch/arm64/boot/dts/ti/k3-j7200-common-proc-board.dts b/arch/arm64/boot/dts/ti/k3-j7200-common-proc-board.dts
        index 6788a3611..9d642eb7a 100644
        --- a/arch/arm64/boot/dts/ti/k3-j7200-common-proc-board.dts
        +++ b/arch/arm64/boot/dts/ti/k3-j7200-common-proc-board.dts
        @@ -593,6 +593,11 @@
                        #gpio-cells = <2>;
                };
        
        +       rtc@6f {
        +               compatible = "microchip,mcp7941x";
        +               reg = <0x6f>;
        +       };
        +
                exp2: gpio@22 {
                        compatible = "ti,tca6424";
                        reg = <0x22>;
      3. Once you have made the changes in the defconfig & the dts files. All you need to do is:

        make linux

        then copy the kernel and DT binaries to your rootfs:

        cp $SDK_INSTALL_DIR:/board-support/linux*/arch/arm64/boot/Image $SDK_INSTALL_DIR:/board-support/linux*/arch/arm64/boot/dts/ti/k3-j7200-common-porc-board.dtb /media/$USER/rootfs/boot


      Best Regards,
      Keerthy