Author: db

  • USB OTG power, take 2

    bq27541, smb345, pm8921 (all in drivers/powr) and ektf3k (drivers/input/touchscreen) seem to know when power state changes. The latter relates to slimport hdmi and receiving power through it. drivers/usb/otg/msm_otg is the other spot the work happens The BQ27541 is a ‘fuel-gauge’ and the data sheet shows it is not involved in decisions about charging. There is […]

  • Graphing bandwidth of a pcap file on arbitrary granularity

    OK it seems like i’ve done this enough times in my career w/ 1-off command line, i thought i would share w/ the group. This may not have the mass-market appeal of the cat videos, but its probably better for productivity. The below script will take a capture file, and then graph it’s bandwidth on […]

  • Wiring for dash

    The wiring diagram for my factory radio is here.  You can tell which specific radio you have by looking in the glove box and seeing a bunch of 3-letter RPO codes (GM) and matching, or by follow the picture here. In my case I have a US8 radio (from the sticker in glove-box):   Which […]

  • USB OTG Charging, Nexus 7 Flo (2013)

    OK, so the USB OTG works just fine, i’ve added the driver for my ‘easycap’ for rearview-camera, and enabled module loading. Now to dig into how to enable the use of charging while using USB OTG. In the msm kernel directory, there is a file ./Documentation/usb/msm_otg.txt. We want ID_A: Configure device to act as host and […]

  • Starting on the Nexus 7 build etc

    So a big change in plans. I bought a used stock AM/FM radio for my vehicle (2011 silverado), and removed the guts. the new N7 is slightly too wide, so a bit of dremelling was needed. Have acquired a single-wire-can to differential canbus converter and a usb canbus reader (for the low-speed canbus, e.g. steering […]