Re: [PATCH] rtc: add support for maxim dallas rtc ds1343 and ds1344

[Alan Cox <alan@lxorguk.ukuu.org.uk>]

On Wed, 7 May 2014 14:42:48 -0700
Andrew Morton <akpm@linux-foundation.org> wrote:

> On Wed,  7 May 2014 00:33:56 +0530 Raghavendra Ganiga <ravi23ganiga@gmail.com> wrote:
> 
> > This is a patch to add support for
> > maxim dallas rtc ds1343 and ds1344
> > 
> > ...
> >
> > +static int ds1343_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
> > +{
> > +	switch (cmd) {
> > +#ifdef RTC_SET_CHARGE
> > +	case RTC_SET_CHARGE:
> > +	{
> > +		int val;
> > +
> > +		if (copy_from_user(&val, (int __user *)arg, sizeof(int)))
> > +			return -EFAULT;
> > +
> > +		return regmap_write(priv->map, DS1343_TRICKLE_REG, val);
> > +	}
> > +	break;
> > +#endif
> > +	}
> 
> Why is RTC_SET_CHARGE defined only for m32r?  It seems pretty generic?
> 
> > +	return -ENOIOCTLCMD;
> > +}
> 
> It's possible that this should be -ENOTTY.  I always forget the rule,
> but Alan never forgets anything ;)

I forget lots 8)

-ENOTTY if it will be returned to user space, -ENOIOCTLCMD is used by
some core code internally as a way for the sub drivers to tell the core
"I didn't handle this, maybe you have a default method ?"

Alan