Changes between Version 14 and Version 15 of USB


Ignore:
Timestamp:
11/05/2019 06:49:42 PM (3 years ago)
Author:
Tim Harvey
Comment:

additional clarification for miniPCIe socket power switch

Legend:

Unmodified
Added
Removed
Modified
  • USB

    v14 v15  
    303303Further information regarding these ioctls can be found throughout the ​[http://lxr.free-electrons.com/source/Documentation/ Linux source documentation].
    304304
    305 === Switched Socket Power ===
    306 
    307 GW53xx and GW54xx boards with -G and later revisions have a power switch added that can enable and disable power on a single slot by toggling a GPIO.  Power is enabled by default. 
    308 
    309 On both GW53xx and GW54xx this is GPIO79 (GPIO bank 3, DIO 15), pad PAD_EIM_DA15__GPIO3_IO15.
    310 
    311 To toggle this GPIO:
    312 
    313 {{{#!bash
     305=== Switched miniPCIe Socket Power
     306On some Gateworks boards the 3.3V power to certain miniPCIe sockets is run through a power switch connected to a GPIO to allow power-cycling devices in the socket. Note that certain miniPCIe form-factor devices may not power-cycle if they backfeed power through PERST# or WLAN_DIS# signals. If power disable capability is provided on a board/socket it is typically on the miniPCIe socket intended for USB based modems (as you can't power cycle devices on the PCI bus without re-enumerating them).
     307
     308Boards featuring miniPCIe socket power disable:
     309||= Board   =||= miniPCIe socket =||= enable =||= gpio =||= Notes =||
     310|| GW53xx-G+ || J6 (modem)        || PAD_EIM_DA15_GPIO3_IO15 || gpio79 || active-high enable ||
     311|| GW54xx-G+ || J7 (modem)        || PAD_EIM_DA15_GPIO3_IO15 || gpio79 || active-high enable ||
     312
     313Examples:
     314 * Toggle socket power in Linux on a GW53xx-G+ (J6) or GW54xx-G+ (J7):
     315{{{#!bash
     316# export gpio79 and configure it as an output
    314317echo 79 > /sys/class/gpio/export
    315318echo out > /sys/class/gpio/gpio79/direction
    316 echo 0 > /sys/class/gpio/gpio79/value # '0' will disable power, '1' will enable power. 
     319echo 0 > /sys/class/gpio/gpio79/value # disable power
     320echo 1 > /sys/class/gpio/gpio79/value # enable power 
    317321}}}
    318322