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The fan controller dynamically regulates fan speed, based on temperature readings, to support optimal thermal performance and energy efficiency. It supports many operating modes and can be configured in real-time through the system nodes.

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Fan controller operation

  • The AMC6821, developed by Texas Instruments, is a flexible temperature monitor and PWM fan controller. It communicates through I²C/SMBus interface, making it ideal for embedded systems requiring active thermal management.
  • The AMC6821 fan controller is integrated with IQ-9075 platforms to manage cooling operations. It supports two operating modes: Manual and Auto. AMC6821 fan controller operates in Auto mode by default. IQ-9075 uses default behavior for dynamic thermal regulation.
  • Developers can refer to AMC6821 controller specific documentation to operate in Manual mode and configure the fan behavior to meet specific system requirements.
  • The kernel driver and respective documentation of AMC6821 fan controller is available at:

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Connection with SoC

  • The AMC6821 fan controller interfaces with I²C bus, using the two pins: GPIO99 and GPIO100
  • The pins are configured in the device tree source file: arch/arm64/boot/dts/qcom/qcs9075-iq-9075-evk.dts
  • Device tree configuration: 
    qup_i2c19_default: qup-i2c19-state
{
      pins = "gpio99", "gpio100";
      function = "qup2_se5";
      drive-strength = <2>;
      bias-pull-up;
}
Note Fan controller is enabled only in IQ-9075.

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Next steps