SDAA069 August   2025 TDA4VL-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Overview of TDA4VL SoC
    2. 1.2 Purpose of the Document
    3. 1.3 Target Audience and Applications
    4. 1.4 Problem Statement
  5. 2Dynamic Frequency Scaling (DFS) in Linux
    1. 2.1 What is DFS?
    2. 2.2 Linux CPUFREQ Framework
    3. 2.3 Supported CPUFREQ Governors
    4. 2.4 DFS Support Status on TI SoCs
  6. 3Linux Thermal Framework
    1. 3.1 Thermal Zones and Trip Points
    2. 3.2 Cooling Mechanisms: Passive vs Active
    3. 3.3 Role of DFS in Passive Cooling
  7. 4Thermal Support on TDA4VL Devices
    1. 4.1 VTM and Bandgap Sensor Initialization
    2. 4.2 Temperature Monitoring via k3_j7xxx_bandgap Driver
  8. 5Enabling CPU Cooling on TDA4VL
    1. 5.1 Patch to Enable CPU Cooling
    2. 5.2 Testing the Cooling Functionality on TDA4VL
  9. 6Scalability Across TDA4 and Sitara Devices
    1. 6.1 Adapting the Implementation
  10. 7Summary
  11. 8References

3.2 Cooling Mechanisms: Passive vs Active

The thermal framework supports various cooling device types, categorized broadly into:

Passive Cooling:

  • Reduces system temperature by lowering performance or power consumption
  • Examples:
    • Lowering CPU frequency using DFS
    • Disabling or hot plugging CPU cores
  • Passive cooling is preferred where silent or low power operation is required.

Active Cooling:

  • Uses external mechanism to lower temperature, such as:
    • Turning on fans
    • Increasing fan speed through PWM control
  • Requires external hardware and driver support (for example, a fan controller)