Re: [PATCH] gpio MIPS/OCTEON: Add a driver for OCTEON's on-chip GPIOpins.

[David Daney]

On 06/20/2013 11:18 AM, Joe Perches wrote:
> On Thu, 2013-06-20 at 11:10 -0700, David Daney wrote:
> > Sorry for not responding earlier, but my e-mail system seems to have
> > malfunctioned with respect to this message...
> []
> > On 06/17/2013 01:51 AM, Linus Walleij wrote:
> > > > +static int octeon_gpio_get(struct gpio_chip *chip, unsigned offset)
> > > > +{
> > > > +       struct octeon_gpio *gpio = container_of(chip, struct octeon_gpio, chip);
> > > > +       u64 read_bits = cvmx_read_csr(gpio->register_base + RX_DAT);
> > > > +
> > > > +       return ((1ull << offset) & read_bits) != 0;
> > >
> > > A common idiom we use for this is:
> > >
> > > return !!(read_bits & (1ull << offset));
> >
> > I hate that idiom, but if its use is a condition of accepting the patch,
> > I will change it.
>
> Or use an even more common idiom and change the
> function to return bool and let the compiler do it.

... but it is part of the gpiochip system interface, so it would have to 
be done kernel wide.

Really I don't like the idea of GPIO lines having Boolean truth values 
associated with them.  Some represent things that are active-high and 
others active-low.  Converting the pin voltage being above or below a 
given threshold to something other than zero or one would in my opinion 
be confusing.

David Daney

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