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.wall...@linaro.org> Signed-off-by: Marc Zyngier <m...@kernel.org> --- 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"); + else + dev_info(&port->dev, "Enabling CBUS%*pbl for GPIO\n", + ngpios, valid_mask); + + 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"); + return 0; } -- 2.28.0
