Hi Greg
On Mon, Jun 27, 2022 at 9:21 AM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Mon, Jun 27, 2022 at 09:06:05AM +0200, Michael Nazzareno Trimarchi wrote:
> > Hi Felipe and Greg
> >
> > I'm starting to write some code to extend the GET_REPORT and let the
> > userspace on the device side to pre-fill the answer on this request.
> > Right now the answer is always 0. The idea is to create a sysfs
> > support to fill reports struct on report request on the host side.
> > This will help to
> > emulate devices that export features report for example. As far as I
> > understand the hidg side just use read and write and read is used to
> > extract
> > the result of SET_REPORT is that the gadget is properly configured. Is
> > it the right direction?
>
> Without code, it is very hard to understand what you are doing here,
> sorry.
>
Agree, I need only a suggestion what is the best way to expose it
> Also, why sysfs?
Let me clarify this point. Right now the userspace manage the set_report
static ssize_t f_hidg_read(struct file *file, char __user *buffer,
size_t count, loff_t *ptr)
{
struct f_hidg *hidg = file->private_data;
if (hidg->use_out_ep)
return f_hidg_intout_read(file, buffer, count, ptr);
else
return f_hidg_ssreport_read(file, buffer, count, ptr);
}
The report can be write from usb side and read on gadget side if use_out_ep
is 0 (this is a configuration). Now, the answer to set_report is done
sync on request
and the usb message is buffered on the kernel side. During the
get_report as far I understand we should reply
the same way on bus. The idea is handle the type and report number and
find it on a list of report that must be prepared
on the gadget side. The hidg ops interface need to handle report
preparation so I was thinking in two solutions:
- sysfs kind of interface
- ioctl like interface
Michael
>
> thanks,
>
> greg k-h
