2013/4/1 Eric Miao <[email protected]>:
> On Sun, Mar 31, 2013 at 11:04 PM, Axel Lin <[email protected]> wrote:
>> clk_enable/clk_disable maintain an enable_count, clk_prepare and
>> clk_unprepare
>> also maintain a prepare_count. These APIs will do prepare/enable when the
>> first
>> user calling these APIs, and do disable/unprepare when the corresponding
>> counter
>> reach 0. Thus We don't need to maintain a clk_enabled counter here.
>
> The original intention is to keep a paired clk enable counter no matter
> how the user calls pwm_enable()/pwm_disable() in pair or not, if that's
> no longer the case.
We don't need to worry that case:
In pwm core, both pwm_enable() and pwm_disable() will always check
PWMF_ENABLED flag.
/**
* pwm_enable() - start a PWM output toggling
* @pwm: PWM device
*/
int pwm_enable(struct pwm_device *pwm)
{
if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
return pwm->chip->ops->enable(pwm->chip, pwm);
return pwm ? 0 : -EINVAL;
}
EXPORT_SYMBOL_GPL(pwm_enable);
/**
* pwm_disable() - stop a PWM output toggling
* @pwm: PWM device
*/
void pwm_disable(struct pwm_device *pwm)
{
if (pwm && test_and_clear_bit(PWMF_ENABLED, &pwm->flags))
pwm->chip->ops->disable(pwm->chip, pwm);
}
EXPORT_SYMBOL_GPL(pwm_disable);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
