lkml.org 
[lkml]   [2019]   [Jan]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH v2 08/10] rtc: bd70528: Initial support for ROHM bd70528 RTC
On Tue, Jan 29, 2019 at 09:01:03AM +0200, Matti Vaittinen wrote:
> On Mon, Jan 28, 2019 at 01:26:56PM -0700, Jerry Hoemann wrote:
> > On Sat, Jan 26, 2019 at 08:30:24AM -0800, Guenter Roeck wrote:
> > > On 1/25/19 3:05 AM, Matti Vaittinen wrote:
> > > > +static int bd70528_set_wake(struct bd70528 *bd70528,
> > > > + int enable, int *old_state)
> > > > +{
> > > > + int ret;
> > > > + unsigned int ctrl_reg;
> > > > +
> > > > + ret = regmap_read(bd70528->chip.regmap, BD70528_REG_WAKE_EN, &ctrl_reg);
> > > > + if (ret)
> > > > + return ret;
> > > > +
> > > > + if (old_state) {
> > > > + if (ctrl_reg & BD70528_MASK_WAKE_EN)
> > > > + *old_state |= BD70528_WAKE_STATE_BIT;
> > > > + else
> > > > + *old_state &= ~BD70528_WAKE_STATE_BIT;
> > > > +
> > > > + if ((!enable) == (!(*old_state & BD70528_WAKE_STATE_BIT)))
> > > > + return 0;
> > >
> > > I think
> > > if (enable == !!(*old_state & BD70528_WAKE_STATE_BIT))
> > > would be much better readable. Even if not, there are way too many ()
> > > in the above conditional.
> > >
> >
> > The substitution is not equivalent to original. I think you mean:
> >
> > if (!!enable == !!(*old_state & BD70528_WAKE_STATE_BIT))
>
> Thanks Jerry! Good catch! I originally wanted that all non-zero values
> of 'enable' would be 'true'. So maybe I just use the original approach
> but get rid of extra parenthesis which were pointed out by Guenter.
>
> if (!enable == !(*old_state & BD70528_WAKE_STATE_BIT))
> should do it just fine, right?
>

The use of "!!" to turn an int into one of two Boolean values (0 | 1)
is used extensively in Linux and as such might make the intent of
the code a bit clearer which I take as checking to see the states
match.

But, I will defer to you and Guenter on the question.

--

-----------------------------------------------------------------------------
Jerry Hoemann Software Engineer Hewlett Packard Enterprise
-----------------------------------------------------------------------------

\
 
 \ /
  Last update: 2019-01-30 01:25    [W:0.062 / U:2.792 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site