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 e39c0df1be5a ("pwm: Introduce the pwm_args concept").

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Fixes: e39c0df1be5a ("pwm: Introduce the pwm_args concept")
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

1 files changed, 17 insertions, 10 deletions

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 680fbc795a0a..22cf3959041c 100644
--- a/drivers/pwm/core.c
+++ b/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;