Hi Mauro,
On Fri, Jun 05, 2020 at 01:13:55PM +0200, Mauro Carvalho Chehab wrote:
> Em Fri, 1 May 2020 00:19:22 +0530
> m...@kernel.org escreveu:
>
> > From: Manivannan Sadhasivam <m...@kernel.org>
> >
> > Hello,
> >
> > This series adds support for MaxLinear/Exar USB to serial converters.
> > This driver only supports XR21V141X series but it can easily be extended
> > to other series in future.
> >
> > This driver is inspired from the initial one submitted by Patong Yang:
> >
> > https://patchwork.kernel.org/patch/10543261/
> >
> > While the initial driver was a custom tty USB driver exposing whole
> > new serial interface ttyXRUSBn, this version is completely based on USB
> > serial core thus exposing the interfaces as ttyUSBn. This will avoid
> > the overhead of exposing a new USB serial interface which the userspace
> > tools are unaware of.
>
> Hmm... I guess you also need the enclosed patch, to ensure that cdc_acm
> won't try to hijack it, when the Kernel is built with both drivers.
>
Ah right. I will include this patch in next iteration. Many thanks!
Regards,
Mani
> Thanks,
> Mauro
>
> [PATCH] usb: cdc-acm: ignore Exar XR21V141X when serial driver is
> built
>
> The RTS/CTS line discipline for this device doesn't follow
> the standard. So, in order to properly support TX, a separate
> driver is needed.
>
> Ensure that cdc_acm will ignore it during probe time, if the
> Kernel is built with support for it.
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab+hua...@kernel.org>
>
> diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
> index ded8d93834ca..f87288834ded 100644
> --- a/drivers/usb/class/cdc-acm.c
> +++ b/drivers/usb/class/cdc-acm.c
> @@ -1889,7 +1889,11 @@ static const struct usb_device_id acm_ids[] = {
> .driver_info = IGNORE_DEVICE,
> },
> #endif
> -
> +#if IS_ENABLED(CONFIG_USB_SERIAL_XR)
> + { USB_DEVICE(0x04e2, 0x1410), /* XR21V141X uses a different rts/cts
> discipline */
> + .driver_info = IGNORE_DEVICE,
> + },
> +#endif
> /*Samsung phone in firmware update mode */
> { USB_DEVICE(0x04e8, 0x685d),
> .driver_info = IGNORE_DEVICE,
>
