Hi,
I'm using pwm-samsung on Exynos4412 for a variable-brightness LED.
When the LED is set to maximum brightness via the pwm-leds driver, we
arrive at pwm_samsung_config with duty_ns = period_ns, i.e. 100% duty
cycle.
This function does:
/* -1UL will give 100% duty. */
--tcmp;
writel(tcmp, our_chip->base + REG_TCMPB(pwm->hwpwm));
I think that comment is incorrect. If tcmp is written as -1UL then the
LED totally turns off. And there is nothing in the Exynos4412 manual
to suggest that -1UL should be set in the TCMP register for 100% duty.
If I remove that --tcmp line, so that 100% duty cycle is handled as
tcmp=0, the problem is solved: the LED turns on at max brightness when
the leds subsystem requests so.
Any ideas? Is this -1UL thing a quirk from older chip versions not
applicable to Exynos4?
Thanks
Daniel
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