Messages in this thread | | | Date | Mon, 20 Aug 2012 07:58:17 +0200 | From | Thierry Reding <> | Subject | Re: [PATCH] leds-lm3530: replace pwm platform functions with generic pwm functions |
| |
On Mon, Aug 20, 2012 at 05:37:48AM +0000, Arnd Bergmann wrote: > On Monday 20 August 2012, Kim, Milo wrote: > > +#ifdef CONFIG_PWM > > +static int lm3530_pwm_request(struct lm3530_data *drvdata) > > +{ > > + int pwm_id; > > + > > + /* if the pwm device exists, skip requesting the device */ > > + if (drvdata->pwm) > > + return 0; > > + > > + pwm_id = drvdata->pdata ? drvdata->pdata->pwm_id : 0; > > + > > + drvdata->pwm = pwm_request(pwm_id, "lm3530-pwm"); > > + drvdata->period_ns = drvdata->pdata ? drvdata->pdata->period_ns : 0; > > + > > + return IS_ERR(drvdata->pwm) ? PTR_ERR(drvdata->pwm) : 0; > > +} > > + > > A few comments on this: > > * Rather than having to do the #ifdef here, I think it would be better if > the PWM subsystem provided stub functions for pwm_request, pwm_config, > pwm_enable, pwm_disable and pwm_free that do nothing, so you can in effect > let the compiler optimize away the above code.
That's actually on my TODO list, but I think it needs to wait until we have gotten rid of all legacy implementations. The stubs would have to move into the !CONFIG_PWM branch, which will in turn break because the legacy implementations would provide non-inlined duplicates.
Thierry [unhandled content-type:application/pgp-signature] | |