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Merge tag 'pwm/for-4.7-rc6' of git://git.kernel.org/pub/scm/linux/ker…
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…nel/git/thierry.reding/linux-pwm

Pull pwm fixes from Thierry Reding:
 "One more fix for some fallout observed after the introduction of the
  atomic API"

* tag 'pwm/for-4.7-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm:
  pwm: Fix pwm_apply_args()
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Linus Torvalds committed Jun 30, 2016
2 parents 4aa34ce + 33cdcee commit 20bfdca
Showing 1 changed file with 10 additions and 6 deletions.
16 changes: 10 additions & 6 deletions include/linux/pwm.h
Original file line number Diff line number Diff line change
Expand Up @@ -464,6 +464,8 @@ static inline bool pwm_can_sleep(struct pwm_device *pwm)

static inline void pwm_apply_args(struct pwm_device *pwm)
{
struct pwm_state state = { };

/*
* PWM users calling pwm_apply_args() expect to have a fresh config
* where the polarity and period are set according to pwm_args info.
Expand All @@ -476,18 +478,20 @@ static inline void pwm_apply_args(struct pwm_device *pwm)
* at startup (even if they are actually enabled), thus authorizing
* polarity setting.
*
* Instead of setting ->enabled to false, we call pwm_disable()
* before pwm_set_polarity() to ensure that everything is configured
* as expected, and the PWM is really disabled when the user request
* it.
* To fulfill this requirement, we apply a new state which disables
* the PWM device and set the reference period and polarity config.
*
* Note that PWM users requiring a smooth handover between the
* bootloader and the kernel (like critical regulators controlled by
* PWM devices) will have to switch to the atomic API and avoid calling
* pwm_apply_args().
*/
pwm_disable(pwm);
pwm_set_polarity(pwm, pwm->args.polarity);

state.enabled = false;
state.polarity = pwm->args.polarity;
state.period = pwm->args.period;

pwm_apply_state(pwm, &state);
}

struct pwm_lookup {
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