Messages in this thread | | | Date | Mon, 1 Apr 2013 15:32:05 +0800 | Subject | Re: [PATCH 3/3] pwm: pxa: Remove clk_enabled field from struct pxa_pwm_chip | From | Axel Lin <> |
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2013/4/1 Eric Miao <eric.y.miao@gmail.com>: > On Sun, Mar 31, 2013 at 11:04 PM, Axel Lin <axel.lin@ingics.com> 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);
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