On Wed, Jun 3, 2009 at 9:22 AM, Anton Vorontsov <avoront...@ru.mvista.com> wrote: > On Wed, Jun 03, 2009 at 02:42:26PM +0200, Stefan Strobl wrote: > [...] >> The led class provides support for setting the brightness, which >> obviously the gpio driver doesn't support. The hardware (mpc52xx_gpt) >> would support it in PWM mode though. I'm now wandering how this could be >> best implemented. >> >> 1) - Create some PWM class similar to the GPIO class >> - Add support for PWM mode in mpc52xx_gpt.c that uses that PWM class >> - And add an interface for the LED to use the PWM class >> >> 2) - Create an LED driver that accesses the mpc52xx_gpt directly. >> >> I think I would be overwhelmed trying to implement (1) but am confident >> to do (2). What do you think is the right approach? > > I'd suggest creating a generic PWM class, i.e. PWMLIB, alike to > GPIOLIB. (2) can be an acceptable approach for now, but for the > long-term solution (1) is the way to go.
What happened to this one? http://ozlabs.org/pipermail/linuxppc-dev/2008-October/063562.html > > The non-lib PWM API is already there, see include/linux/pwm.h, > and arch/arm/mach-pxa/pwm.c as an implementation example. > > Note that PXA implementation is SOC-specific, which is not very > good. > > So I'd suggest creating drivers/pwm/pwmlib.c, borrowing > ideas from gpiolib. And then we can reuse drivers/leds/leds-pwm.c > driver (of course, after adding appropriate OF code into it). > > Sure, as you've said, it could be quite boringly to implement, > could take quite some time to pass all review cycles etc. > But someday someone will have to do this. :-) > > -- > Anton Vorontsov > email: cbouatmai...@gmail.com > irc://irc.freenode.net/bd2 > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- Jon Smirl jonsm...@gmail.com _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev