Re: [PATCH RFC V3.5] leds: trigger: Introduce an USB port trigger

[Alan Stern]

On Thu, 25 Aug 2016, Jacek Anaszewski wrote:

> I'd see it as follows:
> 
> #cat available_ports
> #1-1 1-2 2-1
> 
> #echo "1-1" > new_port
> 
> #cat observed_ports
> #1-1
> 
> #echo "2-1" > new_port
> 
> #cat observed_ports
> #1-1 2-1
> 
> We've already had few discussions about the sysfs designs trying
> to break the one-value-per-file rule for LED class device, and
> there was always strong resistance against.

This scheme has multiple values in both the available_ports and 
observed_ports files.  :-(  Not that I have any better suggestions...

> >> Also a description of the device connected to the port would be a nice
> >> feature, however I am not certain about the feasibility thereof.
> >
> > What kind of description do you mean? Where should it be used / where
> > should it appear?
> >
> 
> Product name/symbol. Actually it should be USB subsystem responsibility
> to provide the means for querying the product name by port id, if it
> is possible at all.

	cat /sys/bus/usb/devices/PORT/product
	cat /sys/bus/usb/devices/PORT/manufacturer

These will work if there is a device registered under PORT.

Alan Stern