[PATCH 1/7] mmc: dw_mmc: lookup for optional biu and ciu clocks

[Russell King - ARM Linux]

On Wed, May 02, 2012 at 03:53:53PM +0100, James Hogan wrote:
> Hi
> 
> On 2 May 2012 06:07, Thomas Abraham <thomas.abraham at linaro.org> wrote:
> > +       if (IS_ERR(host->biu_clk))
> > +               dev_info(&host->dev, "biu clock not available\n");
> 
> In this case, should it set host->biu_clk to NULL or are clk_disable
> and clk_put guaranteed to handle an IS_ERR value?

I keep saying this.  NULL must be treated as a valid reutrn value from
clk_get() and must not use this as a sentinel.  The clk namespace is
that errors are indicated with IS_ERR(clk) returning true.  Everything
else must be assumed to be valid by drivers.