Messages in this thread | | | Date | Tue, 26 May 2015 11:01:33 +0200 | From | Nicolas Ferre <> | Subject | Re: [PATCH 1/2] PWM: atmel: fix incorrect CDTY value after enabling |
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Le 25/05/2015 15:19, Alexandre Belloni a écrit : > CUPD is not flushed before enabling the channel so it will update CDTY/CPRD just > after one period. So we always set CUPD, even when the channel is not enabled. > > Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
BTW, is a "stable tag" needed for this one?
> --- > drivers/pwm/pwm-atmel.c | 35 ++++++++++++++++++----------------- > 1 file changed, 18 insertions(+), 17 deletions(-) > > diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c > index d3c22de9ee47..89f9ca41d9af 100644 > --- a/drivers/pwm/pwm-atmel.c > +++ b/drivers/pwm/pwm-atmel.c > @@ -155,24 +155,25 @@ static void atmel_pwm_config_v1(struct pwm_chip *chip, struct pwm_device *pwm, > struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); > unsigned int val; > > - if (test_bit(PWMF_ENABLED, &pwm->flags)) { > - /* > - * If the PWM channel is enabled, using the update register, > - * it needs to set bit 10 of CMR to 0 > - */ > - atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CUPD, dty); > > - val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR); > - val &= ~PWM_CMR_UPD_CDTY; > - atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); > - } else { > - /* > - * If the PWM channel is disabled, write value to duty and > - * period registers directly. > - */ > - atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CDTY, dty); > - atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CPRD, prd); > - } > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CUPD, dty); > + > + val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR); > + val &= ~PWM_CMR_UPD_CDTY; > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val); > + > + /* > + * If the PWM channel is enabled, only update CDTY by using the update > + * register, it needs to set bit 10 of CMR to 0 > + */ > + if (test_bit(PWMF_ENABLED, &pwm->flags)) > + return; > + /* > + * If the PWM channel is disabled, write value to duty and period > + * registers directly. > + */ > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CDTY, dty); > + atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWMV1_CPRD, prd); > } > > static void atmel_pwm_config_v2(struct pwm_chip *chip, struct pwm_device *pwm, >
-- Nicolas Ferre
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