Hi all, I have found a bug using leds-pwm with the i.MX PWM driver. The first time a non-0 brightness is set through sysfs, this has no effect. It works fine from the 2nd time. The cause of this bug is that leds-pwm.c:led_pwm_set() calls pwm_config() before pwm_enable(), while in the i.MX PWM driver pwm_enable() enables the PWM IP clock, so that a call to pwm_config() has no effect before the first call to pwm_enable(). Several other PWM drivers in drivers/pwm/ work in the same way. pwm-beeper.c and pwm_bl.c also call pwm_config() before pwm_enable(). The PWM documentation does not say if the wrong doers are these PWM users or the i.MX-like PWM drivers. So what should be fixed? Fixing these PWM users would be quite easy since it's a simple swap of the pwm_config() and pwm_enable() calls. This should not produce any glitch since the duty cycle is always set to 0 by these PWM users before calling pwm_disable(). Best regards, Benoît -- To unsubscribe from this list: send the line "unsubscribe linux-leds" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
