UPSTREAM: pwm: Keep PWM state in sync with hardware state

Before the introduction of pwm_args, the core was resetting the PWM
period and polarity states to the reference values (those provided
through the DT, a PWM lookup table or hardcoded in the driver).

Now that all PWM users are correctly using pwm_args to configure their
PWM device, we can safely remove the pwm_apply_args() call in pwm_get()
and of_pwm_get().

We can also get rid of the pwm_set_period() call in pwm_apply_args(),
because PWM users are now directly using pargs->period instead of
pwm_get_period(). By doing that we avoid messing with the current PWM
period.

The only remaining bit in pwm_apply_args() is the initial polarity
setting, and it should go away when all PWM users have been patched to
use the atomic API (with this API the polarity will be set along with
other PWM arguments when configuring the PWM).

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
(cherry picked from commit a8c3862551e063344f80c3e05d595f9d8836f355)

Change-Id: I5112f2d8a7b66e01184984376dcae84decf5ad28
Signed-off-by: David Wu <david.wu@rock-chips.com>

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 01de925be0f3db6b8307d6d649cf5292c180531a..ab86ecddbe1419cc33c2059882d8c3ae78f916f4 100644 (file)
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -612,13 +612,6 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
 
        pwm->label = con_id;
 
 
        pwm->label = con_id;
 

-       /*
-        * FIXME: This should be removed once all PWM users properly make use
-        * of struct pwm_args to initialize the PWM device. As long as this is
-        * here, the PWM state and hardware state can get out of sync.
-        */
-       pwm_apply_args(pwm);
-

 put:
        of_node_put(args.np);
 
 put:
        of_node_put(args.np);
 


@@ -753,13 +746,6 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
        pwm->args.period = chosen->period;
        pwm->args.polarity = chosen->polarity;
 
        pwm->args.period = chosen->period;
        pwm->args.polarity = chosen->polarity;
 

-       /*
-        * FIXME: This should be removed once all PWM users properly make use
-        * of struct pwm_args to initialize the PWM device. As long as this is
-        * here, the PWM state and hardware state can get out of sync.
-        */
-       pwm_apply_args(pwm);
-

 out:
        mutex_unlock(&pwm_lookup_lock);
        return pwm;
 out:
        mutex_unlock(&pwm_lookup_lock);
        return pwm;

diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 661ece188a5161d1ef2fd8a87b9c585adfd68a11..fea78abc8b782a59823ceb498989a7fcda30553f 100644 (file)
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -171,7 +171,6 @@ static inline void pwm_get_args(const struct pwm_device *pwm,
 
 static inline void pwm_apply_args(struct pwm_device *pwm)
 {
 
 static inline void pwm_apply_args(struct pwm_device *pwm)
 {

-       pwm_set_period(pwm, pwm->args.period);

        pwm_set_polarity(pwm, pwm->args.polarity);
 }
 
        pwm_set_polarity(pwm, pwm->args.polarity);
 }