On Sun, 24 Jun 2012, Sebastian Andrzej Siewior wrote:
> On 06/21/2012 12:55 PM, Andrzej Pietrasiewicz wrote:
> > $ echo 1> /cfg/usb-function-gadget/G1/connect
> > $ file.img> /cfg/usb-function-gadget/G1/C1/F1/f_mass_storage/lun0/file
>
> connect should be available at UDC level which triggers the
> pull-up/down of the UDC. The gadget itself should be configured once
> and made available / bound to the UDC. And you may have more
> than once UDC at a time within a single a system.
>
> > Each function, after creating its corresponding directory
> > (/cfg/usb-function-gadget/G1/C1/F1), must be "personalized" by storing
> > its name in the "name" attribute. After that it is possible to create
> > a child item of the same name ("f_mass_storage" here). The common code
> > handles everything from top of the hierarchy up to the function directory.
> > Under the function directory a function-specific stuff provided by each
> > function is used. The function-specific code is abstracted by the above
> > mentioned struct ufg_fn. In the example, the mass storage function is
> > supplied with one LUN.
>
> The hierarchy looks good. C1 vs config1 is just taste.
My taste prefers "config1". Same for "gadget1" and "func1" (or
"function1"). Words -- even short or abbreviated words -- are a lot
more meaningful to people than single letters are.
> > 4. Do we need module parameters for USB descriptors like iManufacturer
> > and similar?
> No. No modules parameters at all. With one exception: Currently we set
> those things via modprobe. As a for compatibility interface I guess we
> have to keep this. In the end I would like have f_mass_storage gone as
> it. We would have a new gadget_storage which provides only the function
> and relies on configfs module and nothing else. The replacement
> g_mass_storage would simply be a small module which takes the
> iManufacturer parameters and others and configures the gadget the way
> the old gadget did i.e. without echo this and echo that.
In any case, iManufacturer should not be adjustable by the user. It
should always be managed by the composite-gadget layer, since it
contains nothing but the index number of the Manufacturer string
descriptor.
Alan Stern
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