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

4.1 VTM and Bandgap Sensor Initialization

The Voltage and Temperature Monitor (VTM) subsystem in the TDA4VL SoC provides hardware support for thermal sensing. The subsystem includes:

  • Multiple on-die temperature sensors (bandgap-based)
  • Infrastructure for monitoring thermal zones

In Linux, VTM hardware is initialized via the k3_j7xxx_bandgap driver. This driver enables:

  • Reading temperature values from multiple thermal sensors on the SoC
  • Exposing the thermal zones to the Linux thermal framework

Once initialized, temperature data becomes accessible through the sysfs interface at: /sys/class/thermal/thermal_zone*/temp