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

[Elaine Zhang <zhangqing@rock-chips.com>]

On 04/10/2017 03:28 AM, Simon Glass wrote:
> Hi,
>
> On 7 April 2017 at 05:02, 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: 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(-)
>
> If the generic uclass change and the rk change can be separated, it is
> good to do it.
>
> Also we should have a test for pwm (test/dm/pwm.c). Are you able to do
> that? If not I could give it a try.
we have no plan to do it.
>
>>
>> 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;
>
> Can you update the comment to indicate what the values mean? E.g. is 0
> the normal polarity and 1 inverted?
0 : normal polarity
1 : inverted polarity
I will update the comment next version.
>
>>          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);
>
> I wonder if it would be better to combine the polarity into the
> pwm_set_config() call? Then we can do everything in one call. If not
> then I think pwm_set_invert() would be a better name.
The polarity set only once, so we set it in pwm_set_init() call.
Using pwm_set_invert, of course, is also possible.
>
>> +       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];
>
> Does this mean that the binding has this argument and we have been ignoring it?
>
> Can you bring in the DT binding file from Linux to U-Boot also?
>
>>
>>          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)
>> +{
>> +       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);
>> +       /**
>>           * set_config() - Set the PWM configuration
>>           *
>>           * @dev:        PWM device to update
>> --
>> 1.9.1
>>
>
> Regards,
> Simon
>
>
>