Re: [PATCH v5] GPIO: add support for 74x164 serial-in/parallel-out 8-bit shift register

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 19 Oct 2010 09:26:42 +0200
Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> wrote:

> On Mon, Oct 18, 2010 at 9:35 PM, Florian Fainelli <florian@openwrt.org> wrote:
> > From: Miguel Gaio <miguel.gaio@efixo.com>
> >
> > This patch adds support for generic 74x164 serial-in/parallel-out 8-bits
> > shift register. This driver can be used as a GPIO output expander.
> >
> ...
> > +struct gen_74x164_chip {
> > +       struct spi_device       *spi;
> > +       struct gpio_chip        gpio_chip;
> > +       struct mutex            lock;
> > +       u8                      port_config;
> > +};
> ...
> > +static void gen_74x164_set_value(struct gpio_chip *gc,
> > +               unsigned offset, int val)
> > +{
> > +       struct gen_74x164_chip *chip = gpio_to_chip(gc);
> > +       bool refresh;
> > +
> > +       mutex_lock(&chip->lock);
> > +       if (val)
> > +               chip->port_config |= (1 << offset);
> > +       else
> > +               chip->port_config &= ~(1 << offset);
> 
> set_bit(), clear_bit() ?

They're only to be used on `unsigned long' types, and `port_config' is
u8.