Messages in this thread | | | Date | Wed, 26 Feb 2020 16:00:51 +0100 | From | Uwe Kleine-König <> | Subject | Re: [PATCH 3/4] pwm: pca9685: initialize all LED registers during probe |
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On Wed, Feb 26, 2020 at 02:52:28PM +0100, Matthias Schiffer wrote: > Initialize all ON delays to 0 during probe, rather than doing it in > pca9685_pwm_enable. > > Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com> > --- > drivers/pwm/pwm-pca9685.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/drivers/pwm/pwm-pca9685.c b/drivers/pwm/pwm-pca9685.c > index 393ab92aa945..370691b21107 100644 > --- a/drivers/pwm/pwm-pca9685.c > +++ b/drivers/pwm/pwm-pca9685.c > @@ -289,13 +289,6 @@ static int pca9685_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) > { > struct pca9685 *pca = to_pca(chip); > > - /* > - * The PWM subsystem does not support a pre-delay. > - * So, set the ON-timeout to 0 > - */ > - regmap_write(pca->regmap, LED_N_ON_L(pwm->hwpwm), 0); > - regmap_write(pca->regmap, LED_N_ON_H(pwm->hwpwm), 0); > - > /* > * Clear the full-off bit. > * It has precedence over the others and must be off. > @@ -388,6 +381,13 @@ static int pca9685_pwm_probe(struct i2c_client *client, > regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_L, 0); > regmap_write(pca->regmap, PCA9685_ALL_LED_OFF_H, 0); > > + /* > + * The PWM subsystem does not support a pre-delay. > + * So, set the ON-timeout to 0 > + */ > + regmap_write(pca->regmap, PCA9685_ALL_LED_ON_H, 0); > + regmap_write(pca->regmap, PCA9685_ALL_LED_ON_L, 0); > +
What is a pre-delay: Something like: _________ ______ _____/ \_________________/ ^ ^
Where ^ marks the period start and then the time between period start and the rising signal is the pre-delay?
If so, the IMHO more right approach is to keep the pre-delay until a new setting is applied and in .get_state ignore the pre-delay. This way you don't modify the output in .probe() which sounds right.
Best regards Uwe
-- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |
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