pwm: Fix uninitialized warnings in pwm_get()

With some versions of gcc (e.g. 4.1.2):

drivers/pwm/core.c: In function ‘pwm_get’:
drivers/pwm/core.c:610: warning: ‘polarity’ may be used uninitialized in this function
drivers/pwm/core.c:609: warning: ‘period’ may be used uninitialized in this function

While these are false positives, we can get rid of them by refactoring
the code to store a pointer to the best match, as suggested before by
Thierry Reding. This does require moving the mutex_unlock() down.

Fixes: d717ea73e36dd565 ("pwm: Fix period and polarity in pwm_get() for non-perfect matches")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

1 files changed, 14 insertions, 15 deletions

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 8c748b17f416..966497d10c6e 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -602,12 +602,9 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
         struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
         const char *dev_id = dev ? dev_name(dev) : NULL;
         struct pwm_chip *chip = NULL;
-        unsigned int index = 0;
         unsigned int best = 0;
-        struct pwm_lookup *p;
+        struct pwm_lookup *p, *chosen = NULL;
         unsigned int match;
-        unsigned int period;
-        enum pwm_polarity polarity;
 
         /* look up via DT first */
         if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
@@ -653,10 +650,7 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
                 }
 
                 if (match > best) {
-                        chip = pwmchip_find_by_name(p->provider);
-                        index = p->index;
-                        period = p->period;
-                        polarity = p->polarity;
+                        chosen = p;
 
                         if (match != 3)
                                 best = match;
@@ -665,17 +659,22 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
                 }
         }
 
-        mutex_unlock(&pwm_lookup_lock);
+        if (!chosen)
+                goto out;
 
-        if (chip)
-                pwm = pwm_request_from_chip(chip, index, con_id ?: dev_id);
-        if (IS_ERR(pwm))
-                return pwm;
+        chip = pwmchip_find_by_name(chosen->provider);
+        if (!chip)
+                goto out;
 
-        pwm_set_period(pwm, period);
-        pwm_set_polarity(pwm, polarity);
+        pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
+        if (IS_ERR(pwm))
+                goto out;
 
+        pwm_set_period(pwm, chosen->period);
+        pwm_set_polarity(pwm, chosen->polarity);
 
+out:
+        mutex_unlock(&pwm_lookup_lock);
         return pwm;
 }
 EXPORT_SYMBOL_GPL(pwm_get);