linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Johan Hovold <johan@kernel.org>
To: Marc Zyngier <maz@kernel.org>
Cc: linux-usb@vger.kernel.org, linux-gpio@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Linus Walleij <linus.walleij@linaro.org>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Johan Hovold <johan@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	kernel-team@android.com
Subject: Re: [PATCH 3/4] USB: serial: ftdi_sio: Log the CBUS GPIO validity
Date: Mon, 7 Dec 2020 15:29:01 +0100	[thread overview]
Message-ID: <X848LXNv3GRmmSXA@localhost> (raw)
In-Reply-To: <20201204164739.781812-4-maz@kernel.org>

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@linaro.org>
> Signed-off-by: Marc Zyngier <maz@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");

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

  reply	other threads:[~2020-12-07 14:29 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-04 16:47 [PATCH 0/4] USB: ftdio_sio: GPIO validity fixes Marc Zyngier
2020-12-04 16:47 ` [PATCH 1/4] gpiolib: cdev: Flag invalid GPIOs as used Marc Zyngier
2020-12-07 14:16   ` Johan Hovold
2020-12-07 14:59     ` Marc Zyngier
2020-12-09  9:25   ` Linus Walleij
2020-12-04 16:47 ` [PATCH 2/4] USB: serial: ftdi_sio: Report the valid GPIO lines to gpiolib Marc Zyngier
2020-12-09  9:28   ` Linus Walleij
2020-12-04 16:47 ` [PATCH 3/4] USB: serial: ftdi_sio: Log the CBUS GPIO validity Marc Zyngier
2020-12-07 14:29   ` Johan Hovold [this message]
2020-12-07 15:00     ` Marc Zyngier
2020-12-07 15:19       ` Johan Hovold
2020-12-09  9:35         ` Linus Walleij
2020-12-09 17:05           ` Johan Hovold
2020-12-09 17:39             ` Johan Hovold
2020-12-04 16:47 ` [PATCH 4/4] USB: serial: ftdi_sio: Drop GPIO line checking dead code Marc Zyngier
2020-12-07  9:55 ` [PATCH 0/4] USB: ftdio_sio: GPIO validity fixes Andy Shevchenko
2020-12-07 14:01 ` Johan Hovold
2020-12-07 14:41   ` Marc Zyngier
2020-12-07 15:08     ` Johan Hovold
2020-12-07 15:34       ` Marc Zyngier
2020-12-07 15:49         ` Johan Hovold
2020-12-09  9:20           ` Linus Walleij
2020-12-09 15:42             ` Johan Hovold

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=X848LXNv3GRmmSXA@localhost \
    --to=johan@kernel.org \
    --cc=bgolaszewski@baylibre.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=kernel-team@android.com \
    --cc=linus.walleij@linaro.org \
    --cc=linux-gpio@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=maz@kernel.org \
    --subject='Re: [PATCH 3/4] USB: serial: ftdi_sio: Log the CBUS GPIO validity' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).