Letux Kernel


Table of Content

Upstream status for GTA04

Upstream status GTA04 4.20

Generally a lot of things are useable, so in many cases patches can be developed on top of mainline


  • Modem-Port:

    • working, but suboptimal pm
    • phy reset workaround missing, giving additional 10mA suspend current if ehci-omap is loaded requires off-mode-enabled (which is enabled in mainline only via a debugfs file)
    • wwan-on-off missing (on gta04a4/5 gpio186 needs to be manually triggered via userspace to enable/disable modem
  • OTG-Port

    • working but some feature missing:
      • id pin status sysfs file missing
      • b_host hacks missing
      • The minimum level the vbus voltage is allowed to drop to while increasing charging current is higher on mainline


  • mostly working
  • libertas (GTA04A4)
    • Mainline has low transfer rate (100KByte/s)
      • Reason: sdio irq not enabled, that should be a simple one-liner patch to dtb. But somehow it is not working easily. Letux kernels have our own workaround giving higher transfer rates.
    • higher power consumption when device is up but not connected (connect to save power), probably not wise to uptream that without cleanly solving the irq problem
  • wl18xx (GTA04A5): working in mainline as well as in letux


  • problematic
  • GTA04A4
    • reset handling bt vs wlan is missing, so problems arise if one tries to use bluetooth without wlan
    • h4 serdev additions are missing (is in discussion with upstream, probably hci_uart will be replaced by a new bt_uart), so pm is not working
  • GTA04A5
    • device tree for hcill is missing (things should be ready for uptream)


  • missing, vsim needs to be switched on and gpio145 needs to be toggled
  • patchset is in review, no conceptual issues

Fuel Gauge access

  • if soc is in too deep powersave, reading out the hdq status fails, there are patches to the clock framework in letux-kernel to fix this

Off mode

  • off mode needs to be manually enabled via debugfs, that is a lower power mode in the soc which reduces suspend current by around 5mA and helps with some ehci problems.


  • only main audio and the soc<->modem link are working
  • no hw routing between modem<->twl4030
  • fm and bluetooth audio devices are missing


  • calibration is missing, workaround:

    uname -r | grep -E 'letux' || xinput set-prop "TSC2007 Touchscreen"  "Evdev Axis Calibration" 256 3840 3840 256
  • conceptual issues with upstreaming that


  • missing, no support for applications using accelerometer via evdev, they are required to use iio

Created: 5 years 5 months ago
by Andreas Kemnade

Updated: 5 years 5 months ago
by Andreas Kemnade

Old Revisions