On Tue, Apr 15, 2014 at 08:41:02AM +0000, Chew, Chiau Ee wrote:
>
>
> > > +static struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev,
> > > + struct resource *r, struct pwm_lpss_boardinfo *info)
> > > {
> > > struct pwm_lpss_chip *lpwm;
> > > - struct resource *r;
> > > int ret;
> > >
> > > - lpwm = devm_kzalloc(&pdev->dev, sizeof(*lpwm), GFP_KERNEL);
> > > + lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL);
> > > if (!lpwm)
> > > - return -ENOMEM;
> > > -
> > > - r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > > + return ERR_PTR(-ENOMEM);
> > >
> > > - lpwm->regs = devm_ioremap_resource(&pdev->dev, r);
> > > + lpwm->regs = devm_ioremap_resource(dev, r);
> > > if (IS_ERR(lpwm->regs))
> > > - return PTR_ERR(lpwm->regs);
> > > -
> > > - lpwm->clk = devm_clk_get(&pdev->dev, NULL);
> > > - if (IS_ERR(lpwm->clk)) {
> > > - dev_err(&pdev->dev, "failed to get PWM clock\n");
> > > - return PTR_ERR(lpwm->clk);
> > > + return lpwm->regs;
> > > +
> > > + if (info) {
> > > + lpwm->clk_rate = info->clk_rate;
> > > + } else {
> > > + lpwm->clk = devm_clk_get(dev, NULL);
> > > + if (IS_ERR(lpwm->clk)) {
> > > + dev_err(dev, "failed to get PWM clock\n");
> > > + return (void *)lpwm->clk;
> >
> > Why the cast here?
>
> Alan, please do correct me if I describe wrongly on the purpose that you add
> the cast here.
>
> As you can see, pwm_lpss_probe() is expected to return a pointer of type
> struct pwm_lpss_chip. On the other hand,
> the return of devm_clk_get() would be a pointer of type struct clk. So if
> were to use lpwm->clk as the return value of pwm_lpss_probe() ,
> a cast would be needed since the pointer type is different from the expected
> one. The compiler would complain on " warning: return from incompatible
> pointer type"
> if without the cast.
I think you can use ERR_CAST() here.
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