Investigate selective WiFi wake capability for power management

[ajlennon]

Background

Currently, the WiFi out-of-band (OOB) wakeup is disabled in the device tree to prevent immediate resume from suspend (IRQ 99 issue). This allows proper deep suspend functionality but removes the ability to wake the system via WiFi events.

Current Status

• Problem: WiFi wakeup-source in device tree causes immediate resume via IRQ 99 (wifi_oob_wakeup)
• Solution: Disabled wakeup-source property in imx93-jaguar-eink.dts
• Impact: System can now suspend properly, but cannot wake via WiFi

Future Requirements

For remote management and monitoring capabilities, we need selective WiFi wake functionality:

1. Wake on LAN (WoL) - Magic packet detection
2. Wake on specific network events - Management commands, updates
3. Scheduled wake via network time sync - Coordinated with RTC alarms
4. Remote diagnostic access - Emergency wake for troubleshooting

Investigation Areas

Hardware Level

• Analyze MAYA W2 (IW612) WiFi module wake capabilities
• Review GPIO4 pin 25 interrupt configuration options
• Investigate programmable wake event filtering

Driver Level

• Study nxp,wifi-wake-host driver implementation
• Research conditional wakeup source enabling/disabling
• Evaluate runtime power management controls

Power Management Integration

• Investigate integration with existing suspend/resume scripts
• Design wake event validation (prevent spurious wakes)
• Coordinate with RTC-based wake scheduling

Software Architecture

• Design userspace control interface for wake policies
• Implement wake event logging and diagnostics
• Create configuration management for different power modes

Technical Details

Current Device Tree Configuration:

wifi_wake_host {
    compatible = "nxp,wifi-wake-host";
    interrupt-parent = <&gpio4>;
    interrupts = <25 IRQ_TYPE_LEVEL_LOW>;  /* ENET2_RD1 - SD2_INT */
    interrupt-names = "host-wake";
    /* wakeup-source; */  /* DISABLED: Prevents proper suspend */
};

Power Management Context:

• Deep suspend working with WiFi suspend/resume scripts
• MAC randomization disabled for stable networking
• System-sleep hooks managing WiFi power state
• Target: 5-year battery life with selective wake capability

Success Criteria

• Maintain current deep suspend functionality
• Enable selective WiFi wake without spurious interrupts
• Provide userspace control over wake policies
• Preserve 5-year battery life target
• Support remote management use cases

Priority

Medium - Important for remote management capabilities but not blocking current functionality.

References

• Device tree: meta-dynamicdevices-bsp/recipes-bsp/device-tree/lmp-device-tree/imx93-jaguar-eink.dts
• WiFi power management: meta-dynamicdevices-bsp/recipes-bsp/eink-power-management/
• Power management debugging session: October 2025