linux-kernel - Re: [PATCH 2/2] USB: serial: cp210x: add gpio-configuration debug printk

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Date:   Fri, 9 Apr 2021 19:22:26 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Johan Hovold <johan@...nel.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>
Cc:     Pho Tran <photranvan0712@...il.com>, Hung.Nguyen@...abs.com,
        Tung.Pham@...abs.com, USB <linux-usb@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] USB: serial: cp210x: add gpio-configuration debug printk

On Fri, Apr 9, 2021 at 6:52 PM Johan Hovold <johan@...nel.org> wrote:
>
> Add a debug printk to dump the GPIO configuration stored in EEPROM
> during probe.
>
> Signed-off-by: Johan Hovold <johan@...nel.org>
> ---
>  drivers/usb/serial/cp210x.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c
> index ceb3a656a075..ee595d1bea0a 100644
> --- a/drivers/usb/serial/cp210x.c
> +++ b/drivers/usb/serial/cp210x.c
> @@ -1543,10 +1543,16 @@ static int cp210x_gpio_init_valid_mask(struct gpio_chip *gc,
>  {
>         struct usb_serial *serial = gpiochip_get_data(gc);
>         struct cp210x_serial_private *priv = usb_get_serial_data(serial);
> +       struct device *dev = &serial->interface->dev;
>         unsigned long altfunc_mask = priv->gpio_altfunc;
>
>         bitmap_complement(valid_mask, &altfunc_mask, ngpios);
>
> +       if (bitmap_empty(valid_mask, ngpios))
> +               dev_dbg(dev, "no pin configured for GPIO\n");

Shouldn't we drop the GPIO device completely in such a case?
Bart, wouldn't it be a good idea for GPIO library to do something like
this on driver's behalf?

> +       else
> +               dev_dbg(dev, "GPIO.%*pbl configured for GPIO\n", ngpios,
> +                               valid_mask);

A nit-pick:
I would change GPIO -> pin in the second message in the first occurrence.

>         return 0;
>  }
>
> --
> 2.26.3
>


-- 
With Best Regards,
Andy Shevchenko