pwm: Fix pwm_apply_args() call sites

pwm_apply_args() is supposed to initialize a PWM device according to the
arguments provided by the DT or the PWM lookup, but this function was
called inside pwm_device_request(), which in turn was called before the
core had a chance to initialize the pwm->args fields.

Fix that by calling pwm_apply_args directly in pwm_get() and of_pwm_get()
after initializing pwm->args field.

This commit also fixes an invalid pointer dereference introduced by
commit e39c0df1 ("pwm: Introduce the pwm_args concept").
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Fixes: e39c0df1 ("pwm: Introduce the pwm_args concept")
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/core.c

@@ -128,13 +128,6 @@ static int pwm_device_request(struct pwm_device *pwm, const char *label)
 	set_bit(PWMF_REQUESTED, &pwm->flags);
 	pwm->label = label;
 
-	/*
-	 * 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);
-
 	return 0;
 }
 
@@ -627,6 +620,13 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *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);
 
@@ -754,13 +754,20 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 	if (!chip)
 		goto out;
 
-	pwm->args.period = chosen->period;
-	pwm->args.polarity = chosen->polarity;
-
 	pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
 	if (IS_ERR(pwm))
 		goto out;
 
+	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;