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>
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 8c748b1..966497d 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -602,12 +602,9 @@
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 @@
}
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 @@
}
}
- mutex_unlock(&pwm_lookup_lock);
+ if (!chosen)
+ goto out;
- if (chip)
- pwm = pwm_request_from_chip(chip, index, con_id ?: dev_id);
+ chip = pwmchip_find_by_name(chosen->provider);
+ if (!chip)
+ goto out;
+
+ pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
if (IS_ERR(pwm))
- return pwm;
+ goto out;
- pwm_set_period(pwm, period);
- pwm_set_polarity(pwm, polarity);
+ 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);