Date: Mon, 9 Jun 2014 15:23:13 +0100
From: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
To: Sascha Silbe <x-linux@infra-silbe.de>
Cc: Johan Hovold <jhovold@gmail.com>, Linus Walleij <linus.walleij@linaro.org>,
        Alexandre Courbot <gnurou@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org, linux-gpio@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] USB: ftdi_sio: add GPIO support
Message-ID: <20140609152313.45f353d6@alan.etchedpixels.co.uk>
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References: <1402320115-13171-1-git-send-email-x-linux@infra-silbe.de>
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>  #include <linux/kernel.h>
>  #include <linux/errno.h>
> +#ifdef CONFIG_GPIOLIB
> +#include <linux/gpio.h>
> +#endif


Please create a new struct, a new file and put all the GPIO stuff in
there rather than #if bombing the driver.

You can then declare blank methods for the gpio stuff if GPIO is not
compiled in - ie in the headers


#ifdef CONFIG_GPIOLIB
extern int ftdi_gpio_open(struct ftdi_private *priv);
etc...
#else
extern inline  int ftdi_gpio_open(struct ftdi_private *priv) { return 0 };
#endif


that keeps the code itself clean and easy to read and also ensures all
the types are checked everywhere we want.

Functionality wise nothing stands out as a problem. I would expect -EBUSY
not -ENXIO if the port was being used for GPIO so could not be used for
tty.

I would favour the new config option.

Alan
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