Re: [U-Boot] [PATCH v2 1/2] power: regulator: pwm: support pwm polarity setting

Hi Kever,

On 11 April 2017 at 02:35, Kever Yang kever.yang@rock-chips.com 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: Elaine Zhang zhangqing@rock-chips.com Signed-off-by: Kever Yang kever.yang@rock-chips.com

---

Changes in v2:

• use pwm_set_invert() instead of pwm_set_init()
• add comment for polarity

drivers/power/regulator/pwm_regulator.c | 16 ++++++++++++++-- drivers/pwm/pwm-uclass.c | 10 ++++++++++ drivers/pwm/rk_pwm.c | 17 ++++++++++++++++- include/pwm.h | 9 +++++++++ 4 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/drivers/power/regulator/pwm_regulator.c b/drivers/power/regulator/pwm_regulator.c index 4875238..3ffe3a1 100644 --- a/drivers/power/regulator/pwm_regulator.c +++ b/drivers/power/regulator/pwm_regulator.c @@ -24,6 +24,12 @@ struct pwm_regulator_info { int pwm_id; /* the period of one PWM cycle */ int period_ns;

•   /*
  

•    * the polarity of one PWM
  

•    * 0: normal polarity
  

•    * 1: inverted polarity
  

•    */
  

•   int polarity;
    struct udevice *pwm;
    /* initialize voltage of regulator */
    unsigned int init_voltage;
  

@@ -49,7 +55,7 @@ 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 +73,12 @@ static int pwm_regulator_set_voltage(struct udevice *dev, int uvolt)

    duty_cycle = pwm_voltage_to_duty_cycle_percentage(dev, uvolt);

•   ret = pwm_set_invert(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 +109,9 @@ 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..d1d7fce 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_invert(struct udevice *dev, uint channel, uint polarity) +{

•   struct pwm_ops *ops = pwm_get_ops(dev);
  

•   if (!ops->set_invert)
  

•           return -ENOSYS;
  

•   return ops->set_invert(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..f003d09 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_invert(struct udevice *dev, uint channel, uint polarity) +{

•   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,
            &regs->ctrl);
  
  

@@ -83,6 +97,7 @@ static int rk_pwm_probe(struct udevice *dev) }

static const struct pwm_ops rk_pwm_ops = {

•   .set_invert     = rk_pwm_set_invert,
    .set_config     = rk_pwm_set_config,
    .set_enable     = rk_pwm_set_enable,
  

}; diff --git a/include/pwm.h b/include/pwm.h index 851915e..66c6bf0 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_invert() - Set the PWM invert
  

•    *
  

•    * @dev:        PWM device to update
  

•    * @channel:    PWM channel to update
  

•    * @polarity:  PWM invert polarity
  

Please document the meaning of this parameter.

•    * @return 0 if OK, -ve on error
  

•    */
  

•   int (*set_invert)(struct udevice *dev, uint channel, uint polarity);
  

•   /**
     * set_config() - Set the PWM configuration
     *
     * @dev:        PWM device to update
  

-- 1.9.1

Can you also please write a test in test/dm/pwm.c with a sandbox pwm driver? A recent example is:

http://patchwork.ozlabs.org/patch/750796/

Regards, Simon