Re: [U-Boot] [PATCH] power: regulator: pwm: support pwm polarity setting

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.yang@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, &regs->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