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Commit 70145f87 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Thierry Reding
Browse files

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: d717ea73 ("pwm: Fix period and polarity in pwm_get() for non-perfect matches")
Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent 7264354c

drivers/pwm/core.c

+14 −15
Original line number Diff line number Diff line
@@ -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);