Re: [PATCH v3 3/3] USB: serial: blacklist USB-UIRT when driver is selected

From: Sean Young <sean@mess.org>
To: Johan Hovold <johan@kernel.org>
Cc: linux-media@vger.kernel.org, linux-usb@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jon Rhees <support@usbuirt.com>, Oliver Neukum <oneukum@suse.com>
Subject: Re: [PATCH v3 3/3] USB: serial: blacklist USB-UIRT when driver is selected
Date: Sat, 15 May 2021 10:56:28 +0100	[thread overview]
Message-ID: <20210515095628.GC31801@gofer.mess.org> (raw)
In-Reply-To: <YJ5hpTqH7Ke+Fv7V@hovoldconsulting.com>

On Fri, May 14, 2021 at 01:40:21PM +0200, Johan Hovold wrote:
> On Thu, May 06, 2021 at 01:44:55PM +0100, Sean Young wrote:
> > The USB-UIRT device has its own driver, so blacklist the fdti driver
> > from using it if the driver has been enabled.
> > 
> > Signed-off-by: Sean Young <sean@mess.org>
> > ---
> >  drivers/usb/serial/ftdi_sio.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> > 
> > diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
> > index 542073d2f0dd..2320bda57796 100644
> > --- a/drivers/usb/serial/ftdi_sio.c
> > +++ b/drivers/usb/serial/ftdi_sio.c
> > @@ -95,7 +95,9 @@ static int   ftdi_jtag_probe(struct usb_serial *serial);
> >  static int   ftdi_NDI_device_setup(struct usb_serial *serial);
> >  static int   ftdi_stmclite_probe(struct usb_serial *serial);
> >  static int   ftdi_8u2232c_probe(struct usb_serial *serial);
> > +#if !IS_ENABLED(CONFIG_IR_UIRT)
> >  static void  ftdi_USB_UIRT_setup(struct ftdi_private *priv);
> > +#endif
> >  static void  ftdi_HE_TIRA1_setup(struct ftdi_private *priv);
> >  
> >  static const struct ftdi_sio_quirk ftdi_jtag_quirk = {
> > @@ -106,9 +108,11 @@ static const struct ftdi_sio_quirk ftdi_NDI_device_quirk = {
> >  	.probe	= ftdi_NDI_device_setup,
> >  };
> >  
> > +#if !IS_ENABLED(CONFIG_IR_UIRT)
> >  static const struct ftdi_sio_quirk ftdi_USB_UIRT_quirk = {
> 
> Please use __maybe_unused instead of sprinkling ifdefs throughout the
> driver.

Good point.

> >  	.port_probe = ftdi_USB_UIRT_setup,
> >  };
> > +#endif
> >  
> >  static const struct ftdi_sio_quirk ftdi_HE_TIRA1_quirk = {
> >  	.port_probe = ftdi_HE_TIRA1_setup,
> > @@ -568,8 +572,10 @@ static const struct usb_device_id id_table_combined[] = {
> >  	{ USB_DEVICE(OCT_VID, OCT_DK201_PID) },
> >  	{ USB_DEVICE(FTDI_VID, FTDI_HE_TIRA1_PID),
> >  		.driver_info = (kernel_ulong_t)&ftdi_HE_TIRA1_quirk },
> > +#if !IS_ENABLED(CONFIG_IR_UIRT)
> >  	{ USB_DEVICE(FTDI_VID, FTDI_USB_UIRT_PID),
> >  		.driver_info = (kernel_ulong_t)&ftdi_USB_UIRT_quirk },
> > +#endif
> 
> This would still be needed.

I agree having the quirk in place would be useful, but if vid/pid is listed
in the id_table then both uirt and ftdi_sio have the same vid/pid listed,
which is not a great idea. How can this work?

Thanks

> 
> >  	{ USB_DEVICE(FTDI_VID, PROTEGO_SPECIAL_1) },
> >  	{ USB_DEVICE(FTDI_VID, PROTEGO_R2X0) },
> >  	{ USB_DEVICE(FTDI_VID, PROTEGO_SPECIAL_3) },
> > @@ -2292,6 +2298,7 @@ static int ftdi_sio_port_probe(struct usb_serial_port *port)
> >  	return 0;
> >  }
> >  
> > +#if !IS_ENABLED(CONFIG_IR_UIRT)
> >  /* Setup for the USB-UIRT device, which requires hardwired
> >   * baudrate (38400 gets mapped to 312500) */
> >  /* Called from usbserial:serial_probe */
> > @@ -2301,6 +2308,7 @@ static void ftdi_USB_UIRT_setup(struct ftdi_private *priv)
> >  	priv->custom_divisor = 77;
> >  	priv->force_baud = 38400;
> >  }
> > +#endif
> >  
> >  /* Setup for the HE-TIRA1 device, which requires hardwired
> >   * baudrate (38400 gets mapped to 100000) and RTS-CTS enabled.  */
> 
> Johan