diff options
authorBoris Brezillon <boris.brezillon@free-electrons.com>2016-06-22 09:25:14 +0200
committerThierry Reding <thierry.reding@gmail.com>2016-06-23 18:37:05 +0200
commit33cdcee04be3b4482be97393167e7561b2584e1e (patch)
parentcc51846ba81ca179a3be20f6313e3b72531888c1 (diff)
pwm: Fix pwm_apply_args()
Commit 5ec803edcb70 ("pwm: Add core infrastructure to allow atomic updates"), implemented pwm_disable() as a wrapper around pwm_apply_state(), and then, commit ef2bf4997f7d ("pwm: Improve args checking in pwm_apply_state()") added missing checks on the ->period value in pwm_apply_state() to ensure we were not passing inappropriate values to the ->config() or ->apply() methods. The conjunction of these 2 commits led to a case where pwm_disable() was no longer succeeding, thus preventing the polarity setting done in pwm_apply_args(). Set a valid period in pwm_apply_args() to ensure polarity setting won't be rejected. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Suggested-by: Brian Norris <briannorris@chromium.org> Fixes: 5ec803edcb70 ("pwm: Add core infrastructure to allow atomic updates") Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Brian Norris <briannorris@chromium.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
1 files changed, 10 insertions, 6 deletions
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 908b67c..c038ae3 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -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.
@@ -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 {