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| author | Boris Brezillon <boris.brezillon@free-electrons.com> | 2016-06-22 09:25:14 +0200 |
|---|---|---|
| committer | Thierry Reding <thierry.reding@gmail.com> | 2016-06-23 18:37:05 +0200 |
| commit | 33cdcee04be3b4482be97393167e7561b2584e1e (patch) | |
| tree | 4aa9751b50c199d016d111abbe4bc011f060effa | |
| parent | cc51846ba81ca179a3be20f6313e3b72531888c1 (diff) | |
| download | lwn-33cdcee04be3b4482be97393167e7561b2584e1e.tar.gz lwn-33cdcee04be3b4482be97393167e7561b2584e1e.zip | |
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>
| -rw-r--r-- | include/linux/pwm.h | 16 |
1 files changed, 10 insertions, 6 deletions
diff --git a/include/linux/pwm.h b/include/linux/pwm.h index 908b67c847cd..c038ae36b10e 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 { |