Hi Kever, On 04/07/2017 08:02 PM, Kever Yang wrote: > The latest kernel PWM drivers enable the polarity settings. When system > run from U-Boot to kerenl, if there are differences in polarity set or > duty cycle, the PMW will re-init: > close -> set polarity and duty cycle -> enable the PWM. > The power supply controled by pwm regulator may have voltage shaking, > which lead to the system not stable. > > Signed-off-by: Kever Yang <kever.y...@rock-chips.com> > --- > > drivers/power/regulator/pwm_regulator.c | 12 ++++++++++-- > drivers/pwm/pwm-uclass.c | 10 ++++++++++ > drivers/pwm/rk_pwm.c | 17 ++++++++++++++++- > include/pwm.h | 9 +++++++++ > 4 files changed, 45 insertions(+), 3 deletions(-) > > diff --git a/drivers/power/regulator/pwm_regulator.c > b/drivers/power/regulator/pwm_regulator.c > index 4875238..f8a6712 100644 > --- a/drivers/power/regulator/pwm_regulator.c > +++ b/drivers/power/regulator/pwm_regulator.c > @@ -24,6 +24,8 @@ struct pwm_regulator_info { > int pwm_id; > /* the period of one PWM cycle */ > int period_ns; > + /* the polarity of one PWM */ > + int polarity; > struct udevice *pwm; > /* initialize voltage of regulator */ > unsigned int init_voltage; > @@ -49,7 +51,7 @@ static int pwm_voltage_to_duty_cycle_percentage(struct > udevice *dev, int req_uV) > int max_uV = priv->max_voltage; > int diff = max_uV - min_uV; > > - return 100 - (((req_uV * 100) - (min_uV * 100)) / diff); > + return ((req_uV * 100) - (min_uV * 100)) / diff; > } > > static int pwm_regulator_get_voltage(struct udevice *dev) > @@ -67,6 +69,12 @@ static int pwm_regulator_set_voltage(struct udevice *dev, > int uvolt) > > duty_cycle = pwm_voltage_to_duty_cycle_percentage(dev, uvolt); > > + ret = pwm_set_init(priv->pwm, priv->pwm_id, priv->polarity); > + if (ret) { > + dev_err(dev, "Failed to init PWM\n"); > + return ret; > + } > + > ret = pwm_set_config(priv->pwm, priv->pwm_id, > (priv->period_ns / 100) * duty_cycle, priv->period_ns); > if (ret) { > @@ -97,9 +105,9 @@ static int pwm_regulator_ofdata_to_platdata(struct udevice > *dev) > debug("%s: Cannot get PWM phandle: ret=%d\n", __func__, ret); > return ret; > } > - /* TODO: pwm_id here from device tree if needed */ > > priv->period_ns = args.args[1]; > + priv->polarity = args.args[2]; > > priv->init_voltage = fdtdec_get_int(blob, node, > "regulator-init-microvolt", -1); > diff --git a/drivers/pwm/pwm-uclass.c b/drivers/pwm/pwm-uclass.c > index c2200af..287a7f3 100644 > --- a/drivers/pwm/pwm-uclass.c > +++ b/drivers/pwm/pwm-uclass.c > @@ -9,6 +9,16 @@ > #include <dm.h> > #include <pwm.h> > > +int pwm_set_init(struct udevice *dev, uint channel, uint polarity) > +{ > + struct pwm_ops *ops = pwm_get_ops(dev); > + > + if (!ops->set_init) > + return -ENOSYS; > + > + return ops->set_init(dev, channel, polarity); > +} > + > int pwm_set_config(struct udevice *dev, uint channel, uint period_ns, > uint duty_ns) > { > diff --git a/drivers/pwm/rk_pwm.c b/drivers/pwm/rk_pwm.c > index 9254f5b..5ff1e00 100644 > --- a/drivers/pwm/rk_pwm.c > +++ b/drivers/pwm/rk_pwm.c > @@ -21,8 +21,22 @@ DECLARE_GLOBAL_DATA_PTR; > struct rk_pwm_priv { > struct rk3288_pwm *regs; > ulong freq; > + uint enable_conf; > }; > > +static int rk_pwm_set_init(struct udevice *dev, uint channel, uint polarity) > +{
"channel" is need? > + struct rk_pwm_priv *priv = dev_get_priv(dev); > + > + debug("%s: polarity=%u\n", __func__, polarity); > + if (polarity) > + priv->enable_conf |= PWM_DUTY_NEGATIVE | PWM_INACTIVE_POSTIVE; > + else > + priv->enable_conf |= PWM_DUTY_POSTIVE | PWM_INACTIVE_NEGATIVE; > + > + return 0; > +} > + > static int rk_pwm_set_config(struct udevice *dev, uint channel, uint > period_ns, > uint duty_ns) > { > @@ -32,7 +46,7 @@ static int rk_pwm_set_config(struct udevice *dev, uint > channel, uint period_ns, > > debug("%s: period_ns=%u, duty_ns=%u\n", __func__, period_ns, duty_ns); > writel(PWM_SEL_SRC_CLK | PWM_OUTPUT_LEFT | PWM_LP_DISABLE | > - PWM_CONTINUOUS | PWM_DUTY_POSTIVE | PWM_INACTIVE_POSTIVE | > + PWM_CONTINUOUS | priv->enable_conf | > RK_PWM_DISABLE, > ®s->ctrl); > > @@ -83,6 +97,7 @@ static int rk_pwm_probe(struct udevice *dev) > } > > static const struct pwm_ops rk_pwm_ops = { > + .set_init = rk_pwm_set_init, > .set_config = rk_pwm_set_config, > .set_enable = rk_pwm_set_enable, > }; > diff --git a/include/pwm.h b/include/pwm.h > index 851915e..a66ee1f 100644 > --- a/include/pwm.h > +++ b/include/pwm.h > @@ -14,6 +14,15 @@ > /* struct pwm_ops: Operations for the PWM uclass */ > struct pwm_ops { > /** > + * set_init() - Set the PWM invert > + * > + * @dev: PWM device to update > + * @channel: PWM channel to update > + * @polarity: PWM invert polarity > + * @return 0 if OK, -ve on error > + */ > + int (*set_init)(struct udevice *dev, uint channel, uint polarity); Is there a reason about using int type? It's always return 0... Otherwise do you have a plan to use "int" type? Best Regards, Jaehoon Chung > + /** > * set_config() - Set the PWM configuration > * > * @dev: PWM device to update > _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot