On Wed, Nov 14, 2012 at 9:58 AM, Alban Bedel <alban.be...@avionic-design.de> wrote: > 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: Alban Bedel <alban.be...@avionic-design.de>
Acked-by: Alexandre Pereira da Silva <aletes....@gmail.com> > --- > drivers/pwm/pwm-lpc32xx.c | 17 ++++++++++++++++- > 1 files changed, 16 insertions(+), 1 deletions(-) > > diff --git a/drivers/pwm/pwm-lpc32xx.c b/drivers/pwm/pwm-lpc32xx.c > index adb87f0..03ec3ff 100644 > --- a/drivers/pwm/pwm-lpc32xx.c > +++ b/drivers/pwm/pwm-lpc32xx.c > @@ -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 value is a follow: > + * > + * DUTY HIGH LEVEL > + * 1 99.9% > + * 25 90.0% > + * 128 50.0% > + * 220 10.0% > + * 255 0.1% > + * 0 0.0% > + * > + * In other word the in-register value is duty % 256 with duty > + * 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)); > -- > 1.7.0.4 > -- 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/
