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Diffstat (limited to 'Documentation/usb/gadget_serial.txt')
| -rw-r--r-- | Documentation/usb/gadget_serial.txt | 35 |
1 files changed, 26 insertions, 9 deletions
diff --git a/Documentation/usb/gadget_serial.txt b/Documentation/usb/gadget_serial.txt index 815f5c2301ff..9b22bd14c348 100644 --- a/Documentation/usb/gadget_serial.txt +++ b/Documentation/usb/gadget_serial.txt @@ -1,6 +1,7 @@ Linux Gadget Serial Driver v2.0 11/20/2004 + (updated 8-May-2008 for v2.3) License and Disclaimer @@ -31,7 +32,7 @@ Prerequisites ------------- Versions of the gadget serial driver are available for the 2.4 Linux kernels, but this document assumes you are using -version 2.0 or later of the gadget serial driver in a 2.6 +version 2.3 or later of the gadget serial driver in a 2.6 Linux kernel. This document assumes that you are familiar with Linux and @@ -40,6 +41,12 @@ standard utilities, use minicom and HyperTerminal, and work with USB and serial devices. It also assumes you configure the Linux gadget and usb drivers as modules. +With version 2.3 of the driver, major and minor device nodes are +no longer statically defined. Your Linux based system should mount +sysfs in /sys, and use "mdev" (in Busybox) or "udev" to make the +/dev nodes matching the sysfs /sys/class/tty files. + + Overview -------- @@ -104,15 +111,8 @@ driver. All this are listed under "USB Gadget Support" when configuring the kernel. Then rebuild and install the kernel or modules. -The gadget serial driver uses major number 127, for now. So you -will need to create a device node for it, like this: - - mknod /dev/ttygserial c 127 0 - -You only need to do this once. - Then you must load the gadget serial driver. To load it as an -ACM device, do this: +ACM device (recommended for interoperability), do this: modprobe g_serial use_acm=1 @@ -125,6 +125,23 @@ controller driver. This must be done each time you reboot the gadget side Linux system. You can add this to the start up scripts, if desired. +Your system should use mdev (from busybox) or udev to make the +device nodes. After this gadget driver has been set up you should +then see a /dev/ttyGS0 node: + + # ls -l /dev/ttyGS0 | cat + crw-rw---- 1 root root 253, 0 May 8 14:10 /dev/ttyGS0 + # + +Note that the major number (253, above) is system-specific. If +you need to create /dev nodes by hand, the right numbers to use +will be in the /sys/class/tty/ttyGS0/dev file. + +When you link this gadget driver early, perhaps even statically, +you may want to set up an /etc/inittab entry to run "getty" on it. +The /dev/ttyGS0 line should work like most any other serial port. + + If gadget serial is loaded as an ACM device you will want to use either the Windows or Linux ACM driver on the host side. If gadget serial is loaded as a bulk in/out device, you will want to use the |