pwm: lpc32xx: Fix the PWM polarity (a9a18e06) · Commits · 戴 / test

The duty cycles value goes from 1 (99% HIGH) to 256 (0% HIGH) but it is stored modulo 256 in the register as it is only 8 bits wide. Signed-off-by:

drivers/pwm/pwm-lpc32xx.c

+16 −1

Original line number	Diff line number	Diff line
		@@ -49,9 +49,24 @@ static int lpc32xx_pwm_config(struct pwm_chip chip, struct pwm_device pwm,
		c = 0; /* 0 set division by 256 */
		period_cycles = c;

		/* The duty-cycle value is as follows:
		*
		* DUTY-CYCLE HIGH LEVEL
		* 1 99.9%
		* 25 90.0%
		* 128 50.0%
		* 220 10.0%
		* 255 0.1%
		* 0 0.0%
		*
		* In other words, the register value is duty-cycle % 256 with
		* duty-cycle in the range 1-256.
		*/
		c = 256 * duty_ns;
		do_div(c, period_ns);
		duty_cycles = c;
		if (c > 255)
		c = 255;
		duty_cycles = 256 - c;

		writel(PWM_ENABLE \| PWM_RELOADV(period_cycles) \| PWM_DUTY(duty_cycles),
		lpc32xx->base + (pwm->hwpwm << 2));