PMIC Configuration¶

During the system boot, MB1 enables system power rails for CPU, CORE, and DRAM and completes some system PMIC configurations. The typical configurations are:

Enabling rails
Setting rail voltages
Configuring FPS

Enabling and setting of voltages of rails might require the following platform-specific configurations:

I2C commands to devices
PWM commands to devices
MMIO accesses to Tegra registers, read-modify-write or write-only
Delay after the commands

The entries in PMIC configuration files are common or rail-specific.

Common Configuration¶

The common configuration parameters apply to all rails.

Each PMIC common configuration is of the following form:

/ {
    pmic {
      <parameter> = <value>;
      };
  };

where <parameter> is one of the following:

<parameter>	Description
rail-count	Number of rails in the configuration file.
command-retries-count	The number of allowed command attempts.
wait-before-start-bus-clear-us	Wait timeout in microseconds before issuing the bus clear command. - The wait time is calculated as 1 <<n microseconds where n is provided by this parameter.

Rail-Specific Configuration¶

The rail-specific configuration are divided into blocks:

Each rail can have one or more blocks.
Each block can have only one command type: - I2C - PWM - MMIO

Each PMIC rail-specific configuration is of the following form:

/ {
    pmic {
      <rail-name> {
        block@<index> {
          <parameter> = <value>;
        };
      };
   };
};

where:

<rail-name> identifies the rail and is one of the following:

Name	Description
system	System PMIC configuration.
cpu/cpu0	CPU rail configuration.
cpu1	CPU rail configuration.
core	Core/SOC rail configuration.
memio	DRAM-related rail configuration.
thermal	External thermal sensor configuration.
platform	Platform’s other 12C configuration.

block-<index>: The rail-specific commands are divided into blocks.

Each rail can have multiple blocks, and each block of rails is indexed starting from 0.
<parameter> is one of the following:

<parameter>	Description
`<type>`	Type of commands in the block. Valid properties are i2c-controller, pwm or mmio.
commands { <group-name> { command@N { reg-addr = <reg-address>; mask = <reg-mask>; value = <reg-value>; }; }; };	`<group-name>` node is the logical command group name and it is optional. N is the sequential number for the command starting from 0. MMIO or I2C commands (based on type). `mmio` MMIO command (valid only if block has mmio property), where the following applies: `<address>` is absolute address of MMIO register. `<mask>` is the 32-bit mask that is applied to the value read from the MMIO address to facilitate the read-modify-write operation. `<value>` value written into the register. i2c controller 12c command, where the following applies: `<address>` is the I2c slave register address. `<mask>` is I2C slave mask that is applied to the value read from the I2C slave register, to facilitate read-modify-write operation. `<value>` value written into the register.
`<12c-parameter>`	12C parameter (valid only if the block has the i2c-controller property). block-delay Delay (in microseconds), after each command in the block. `<index>` is the block index (starting from 0). i2c-controller-id i2c-controller instance. slave-addr 7-bit i2C slave address. reg-data-size Register size in bits. Valid values are 0 (1 byte) and 16 (2-byte). reg-addr-size Register address size in bits. Valid values are 0 (1-byte), 8 (1-byte), and 16 (2-byte).
`pwm`	PWM parameter (valid only if the block has the pwm property). controller-id PWM controller instance (0-7) source-frq-hz PWM clock source frequency (in Hz) period-ns PWM period (in nanoseconds) min-microvolts Vout from the PWM regulator if duty cycle is 100. max-microvolts Vout from the PWM regulator if duty cycle is 100. init-microvolts Vout from the PWM regulator after initialization. enable 0 (configures PWM, but does not enable). 1 (enable PWM after configuration).