Document the console option for DEVNAME:0.0 style addressing for serial ports. Suggested-by: Sebastian Reichel <sre@xxxxxxxxxx> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx> --- .../admin-guide/kernel-parameters.txt | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -785,6 +785,25 @@ Documentation/networking/netconsole.rst for an alternative. + <DEVNAME>:<n>.<n>[,options] + Use the specified serial port on the serial core bus. + The addressing uses DEVNAME of the physical serial port + device, followed by the serial core controller instance, + and the serial port instance. The options are the same + as documented for the ttyS addressing above. + + The mapping of the serial ports to the tty instances + can be viewed with: + + $ ls -d /sys/bus/serial-base/devices/*:*.*/tty/* + /sys/bus/serial-base/devices/00:04:0.0/tty/ttyS0 + + In the above example, the console can be addressed with + console=00:04:0.0. Note that a console addressed this + way will only get added when the related device driver + is ready. The use of an earlycon parameter in addition to + the console may be desired for console output early on. + uart[8250],io,<addr>[,options] uart[8250],mmio,<addr>[,options] uart[8250],mmio16,<addr>[,options] -- 2.44.0
