RE: [PATCH] clk: Add (devm_)clk_get_optional() functions

[Phil Edworthy]

Hi Andy,

On 20 November 2018 10:39 Andy Shevchenko wrote:
> On Mon, Nov 19, 2018 at 02:12:59PM +0000, Phil Edworthy wrote:
> > This adds clk_get_optional() and devm_clk_get_optional() functions to
> > get optional clocks.
> > They behave the same as (devm_)clk_get except where there is no clock
> > producer. In this case, instead of returning -ENOENT, the function
> > returns NULL. This makes error checking simpler and allows
> > clk_prepare_enable, etc to be called on the returned reference without
> > additional checks.
> 
> >  - Instead of messing with the core functions, simply wrap them for the
> >    _optional() versions. By putting clk_get_optional() inline in the header
> >    file, we can get rid of the arch specific patches as well.
> 
> Fine if it would have no surprises with error handling.
There shouldn't be any surprises. My earlier attempts at implementing this
were hampered by the fact that of_clk_get_by_name() can return -EINVAL
in some circumstances. By directly wrapping the (devm_)clk_get() functions
that problem goes away.

> > +	if (ERR_PTR(-ENOENT))
Huh? That wasn't the code I sent...

> > +		return NULL;
> > +	else
> > +		return clk;
> 
> return clk == ERR_PTR(-ENOENT) ? NULL : clk;
> 
> ?
> 
> > +	if (clk == ERR_PTR(-ENOENT))
> > +		return NULL;
> > +	else
> > +		return clk;
> 
> Ditto.
Sure, will fix both.

Thanks
Phil