On Fri, Dec 04, 2020 at 04:47:38PM +0000, Marc Zyngier wrote: > The validity of the ftdi CBUS GPIO is pretty hidden so far, > and finding out *why* some GPIOs don't work is sometimes > hard to identify. So let's help the user by displaying the > map of the CBUS pins that are valid for a GPIO. > > Also, tell the user about the magic ftx-prog tool that can > make GPIOs appear: https://github.com/richardeoin/ftx-prog > > Suggested-by: Linus Walleij <linus.walleij@xxxxxxxxxx> > Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> > --- > drivers/usb/serial/ftdi_sio.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c > index 13e575f16bcd..b9d3b33891fc 100644 > --- a/drivers/usb/serial/ftdi_sio.c > +++ b/drivers/usb/serial/ftdi_sio.c > @@ -2012,6 +2012,15 @@ static int ftdi_gpio_init_valid_mask(struct gpio_chip *gc, > > bitmap_complement(valid_mask, &map, ngpios); > > + if (bitmap_empty(valid_mask, ngpios)) > + dev_warn(&port->dev, "No usable GPIO\n"); This isn't an error of any kind, and certainly not something that deserves a warning in the system log on every probe. Not everyone cares about the GPIO interface. > + else > + dev_info(&port->dev, "Enabling CBUS%*pbl for GPIO\n", > + ngpios, valid_mask); And while printing this mask has some worth I'm still reluctant to be spamming the logs with it. Just like gpolib has a dev_dbg() for registering chips, this should probably be demoted to KERN_DEBUG as well. > + > + if (!bitmap_full(valid_mask, ngpios)) > + dev_warn_once(&port->dev, "Consider using a tool such as ftx-prog to enable GPIOs if required\n"); > + And again, this is not something that belongs in the logs of just about every system with an attached ftdi device. While not possible to combine with the valid_mask approach, this is something which we could otherwise add to the request() callback for the first request that fails due to the mux configuration. > return 0; > } Johan
