On Sun, Jun 21, 2015 at 12:12 AM, Stefan Agner <stefan@xxxxxxxx> wrote: > This driver allows to use the CBUS pins, e.g. CBUS 0-3 on FT232R > type of devices. Note that the pins need to be configured first > by using I/O mode signal option in the EEPROM. This is _not_ the > factory default configuration of any of the four pins. > > See also FTDI's Application Note AN_232R-01. > > Signed-off-by: Stefan Agner <stefan@xxxxxxxx> I see no big problems with this driver but I guess the serial portions are the controversial parts. > +++ b/drivers/gpio/gpio-ftdi-cbus.c > @@ -0,0 +1,167 @@ > +/* > + * gpiolib support for FTDI SIO chips supporting CBUS GPIO's (FT232R class) > + * > + * Copyright 2015 Stefan Agner > + * > + * Author: Stefan Agner <stefan@xxxxxxxx> > + * > + * This program is free software; you can redistribute it and/or modify it > + * under the terms of the GNU General Public License as published by the > + * Free Software Foundation; either version 2 of the License, or (at your > + * option) any later version. > + * > + * Note: To use the GPIOs on CBUS the signal option need to be set to > + * I/O mode in EEPROM! > + */ > + > +#include <linux/kernel.h> > +#include <linux/slab.h> > +#include <linux/module.h> > +#include <linux/gpio.h> #include <linux/gpio/driver.h> should be enough. > +static int ftdi_cbus_gpio_direction_input(struct gpio_chip *chip, > + unsigned offset) > +{ > + struct ftdi_cbus_gpio *fcg = to_ftdi_cbus_gpio(chip); > + > + fcg->cbus_mask &= ~((1 << offset) << 4); I usually replace: (1 << offset) with #include <linux/bitops.h> BIT(offset) so it's clear what is happening. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html