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pwm: Fix uninitialized warnings in pwm_get()

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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: d717ea73e3 ("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>
This commit is contained in:
Geert Uytterhoeven 2014-08-28 11:03:14 +02:00 • committed by Thierry Reding
parent 7264354c0c
commit 70145f8713
1 changed files with 14 additions and 15 deletions
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29
drivers/pwm/core.c
View file

@ -602,12 +602,9 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER); struct pwm_device *pwm = ERR_PTR(-EPROBE_DEFER);
const char *dev_id = dev ? dev_name(dev) : NULL; const char *dev_id = dev ? dev_name(dev) : NULL;
struct pwm_chip *chip = NULL; struct pwm_chip *chip = NULL;
unsigned int index = 0;
unsigned int best = 0; unsigned int best = 0;
struct pwm_lookup *p; struct pwm_lookup *p, *chosen = NULL;
unsigned int match; unsigned int match;
unsigned int period;
enum pwm_polarity polarity;
/* look up via DT first */ /* look up via DT first */
if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) 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) { if (match > best) {
chip = pwmchip_find_by_name(p->provider); chosen = p;
index = p->index;
period = p->period;
polarity = p->polarity;
if (match != 3) if (match != 3)
best = match; 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) chip = pwmchip_find_by_name(chosen->provider);
pwm = pwm_request_from_chip(chip, index, con_id ?: dev_id); if (!chip)
goto out;
pwm = pwm_request_from_chip(chip, chosen->index, con_id ?: dev_id);
if (IS_ERR(pwm)) 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; return pwm;
} }
EXPORT_SYMBOL_GPL(pwm_get); EXPORT_SYMBOL_GPL(pwm_get);