SPRADC5 January   2024

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1PMIC and Power Custom Changes
  5. 2Pinmux
    1. 2.1 Steps to Configure the PinMux
    2. 2.2 Manual Audit of the Pinmux
  6. 3Custom DDR Related Changes
  7. 4Minimal Kernel DT to Start With
  8. 5Boot Mode Support Summary
    1. 5.1 No-Boot Mode
    2. 5.2 UART Boot Mode
    3. 5.3 OSPI/QSPI/SPI/xSPI/Serial NAND
  9. 6Commonly Encountered Issues During Custom Board Bring Up

1 PMIC and Power Custom Changes

Custom boards can have different PMICs sourcing the SoC voltage domains. Choosing different PMIC can be due to cost benefits, different power requirements and availability. The PMIC configuration is typically done in the safety aware MCU R5F0. R5 SPL primarily configures the CPU rail with AVS compensated voltages. Changes will be needed for custom PMIC in 2 places:

  1. Device Tree: The device tree for WKUP_I2C0 needs to be populated with the right PMIC nodes. Example: arch/arm/dts/k3-j721e-r5-common-proc-board.dtsHook the right regulator node as the supply for VTM node.
    &wkup_i2c0 {
        u-boot,dm-spl;
        tps659413a: tps659413a@48 {
                reg = <0x48>;
                compatible = "ti,tps659413";
                u-boot,dm-spl;
                pinctrl-names = "default";
                pinctrl-0 = <&wkup_i2c0_pins_default>;
                clock-frequency = <400000>;
 
                regulators: regulators {
                        u-boot,dm-spl;
                        buck12_reg: buck12 {
                                /*VDD_MPU*/
                                regulator-name = "buck12";
                                regulator-min-microvolt = <800000>;
                                regulator-max-microvolt = <1250000>;
                                regulator-always-on;
                                regulator-boot-on;
                                u-boot,dm-spl;
                        };
                };
        };
 
&wkup_vtm0 {
        vdd-supply-2 = <&buck12_reg>;
        u-boot,dm-spl;
};
    2. 
                                
  2. CONFIG changes
                                        for PMIC in configs/j721e_evm_r5_defconfig. For example,
                                        below are the changes needed for TPS65941 PMIC:
    3. 
                                
  3. 
                                        
    CONFIG_DM_PMIC=y
CONFIG_PMIC_TPS65941=y
CONFIG_DM_REGULATOR=y
CONFIG_SPL_DM_REGULATOR=y
CONFIG_DM_REGULATOR_TPS65941=y
    
                                
    4.