X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?p=kvmfornfv.git;a=blobdiff_plain;f=kernel%2Fdrivers%2Fpwm%2Fcore.c;h=d24ca5f281b4bbd98e5ce86e8f454c270d86fe10;hp=ba34c7d8904232de070b78d4565377c1fab75740;hb=e09b41010ba33a20a87472ee821fa407a5b8da36;hpb=f93b97fd65072de626c074dbe099a1fff05ce060

diff --git a/kernel/drivers/pwm/core.c b/kernel/drivers/pwm/core.c
index ba34c7d89..d24ca5f28 100644
--- a/kernel/drivers/pwm/core.c
+++ b/kernel/drivers/pwm/core.c
@@ -200,6 +200,8 @@ static void of_pwmchip_remove(struct pwm_chip *chip)
  * pwm_set_chip_data() - set private chip data for a PWM
  * @pwm: PWM device
  * @data: pointer to chip-specific data
+ *
+ * Returns: 0 on success or a negative error code on failure.
  */
 int pwm_set_chip_data(struct pwm_device *pwm, void *data)
 {
@@ -215,6 +217,8 @@ EXPORT_SYMBOL_GPL(pwm_set_chip_data);
 /**
  * pwm_get_chip_data() - get private chip data for a PWM
  * @pwm: PWM device
+ *
+ * Returns: A pointer to the chip-private data for the PWM device.
  */
 void *pwm_get_chip_data(struct pwm_device *pwm)
 {
@@ -223,13 +227,18 @@ void *pwm_get_chip_data(struct pwm_device *pwm)
 EXPORT_SYMBOL_GPL(pwm_get_chip_data);
 
 /**
- * pwmchip_add() - register a new PWM chip
+ * pwmchip_add_with_polarity() - register a new PWM chip
  * @chip: the PWM chip to add
+ * @polarity: initial polarity of PWM channels
  *
  * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
- * will be used.
+ * will be used. The initial polarity for all channels is specified by the
+ * @polarity parameter.
+ *
+ * Returns: 0 on success or a negative error code on failure.
  */
-int pwmchip_add(struct pwm_chip *chip)
+int pwmchip_add_with_polarity(struct pwm_chip *chip,
+			      enum pwm_polarity polarity)
 {
 	struct pwm_device *pwm;
 	unsigned int i;
@@ -259,6 +268,8 @@ int pwmchip_add(struct pwm_chip *chip)
 		pwm->chip = chip;
 		pwm->pwm = chip->base + i;
 		pwm->hwpwm = i;
+		pwm->polarity = polarity;
+		mutex_init(&pwm->lock);
 
 		radix_tree_insert(&pwm_tree, pwm->pwm, pwm);
 	}
@@ -279,6 +290,21 @@ out:
 	mutex_unlock(&pwm_lock);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
+
+/**
+ * pwmchip_add() - register a new PWM chip
+ * @chip: the PWM chip to add
+ *
+ * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
+ * will be used. The initial polarity for all channels is normal.
+ *
+ * Returns: 0 on success or a negative error code on failure.
+ */
+int pwmchip_add(struct pwm_chip *chip)
+{
+	return pwmchip_add_with_polarity(chip, PWM_POLARITY_NORMAL);
+}
 EXPORT_SYMBOL_GPL(pwmchip_add);
 
 /**
@@ -287,6 +313,8 @@ EXPORT_SYMBOL_GPL(pwmchip_add);
  *
  * Removes a PWM chip. This function may return busy if the PWM chip provides
  * a PWM device that is still requested.
+ *
+ * Returns: 0 on success or a negative error code on failure.
  */
 int pwmchip_remove(struct pwm_chip *chip)
 {
@@ -321,10 +349,13 @@ EXPORT_SYMBOL_GPL(pwmchip_remove);
 
 /**
  * pwm_request() - request a PWM device
- * @pwm_id: global PWM device index
+ * @pwm: global PWM device index
  * @label: PWM device label
  *
  * This function is deprecated, use pwm_get() instead.
+ *
+ * Returns: A pointer to a PWM device or an ERR_PTR()-encoded error code on
+ * failure.
  */
 struct pwm_device *pwm_request(int pwm, const char *label)
 {
@@ -359,9 +390,9 @@ EXPORT_SYMBOL_GPL(pwm_request);
  * @index: per-chip index of the PWM to request
  * @label: a literal description string of this PWM
  *
- * Returns the PWM at the given index of the given PWM chip. A negative error
- * code is returned if the index is not valid for the specified PWM chip or
- * if the PWM device cannot be requested.
+ * Returns: A pointer to the PWM device at the given index of the given PWM
+ * chip. A negative error code is returned if the index is not valid for the
+ * specified PWM chip or if the PWM device cannot be requested.
  */
 struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
 					 unsigned int index,
@@ -402,6 +433,8 @@ EXPORT_SYMBOL_GPL(pwm_free);
  * @pwm: PWM device
  * @duty_ns: "on" time (in nanoseconds)
  * @period_ns: duration (in nanoseconds) of one cycle
+ *
+ * Returns: 0 on success or a negative error code on failure.
  */
 int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
 {
@@ -426,7 +459,10 @@ EXPORT_SYMBOL_GPL(pwm_config);
  * @pwm: PWM device
  * @polarity: new polarity of the PWM signal
  *
- * Note that the polarity cannot be configured while the PWM device is enabled
+ * Note that the polarity cannot be configured while the PWM device is
+ * enabled.
+ *
+ * Returns: 0 on success or a negative error code on failure.
  */
 int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
 {
@@ -438,29 +474,49 @@ int pwm_set_polarity(struct pwm_device *pwm, enum pwm_polarity polarity)
 	if (!pwm->chip->ops->set_polarity)
 		return -ENOSYS;
 
-	if (test_bit(PWMF_ENABLED, &pwm->flags))
-		return -EBUSY;
+	mutex_lock(&pwm->lock);
+
+	if (pwm_is_enabled(pwm)) {
+		err = -EBUSY;
+		goto unlock;
+	}
 
 	err = pwm->chip->ops->set_polarity(pwm->chip, pwm, polarity);
 	if (err)
-		return err;
+		goto unlock;
 
 	pwm->polarity = polarity;
 
-	return 0;
+unlock:
+	mutex_unlock(&pwm->lock);
+	return err;
 }
 EXPORT_SYMBOL_GPL(pwm_set_polarity);
 
 /**
  * pwm_enable() - start a PWM output toggling
  * @pwm: PWM device
+ *
+ * Returns: 0 on success or a negative error code on failure.
  */
 int pwm_enable(struct pwm_device *pwm)
 {
-	if (pwm && !test_and_set_bit(PWMF_ENABLED, &pwm->flags))
-		return pwm->chip->ops->enable(pwm->chip, pwm);
+	int err = 0;
 
-	return pwm ? 0 : -EINVAL;
+	if (!pwm)
+		return -EINVAL;
+
+	mutex_lock(&pwm->lock);
+
+	if (!test_and_set_bit(PWMF_ENABLED, &pwm->flags)) {
+		err = pwm->chip->ops->enable(pwm->chip, pwm);
+		if (err)
+			clear_bit(PWMF_ENABLED, &pwm->flags);
+	}
+
+	mutex_unlock(&pwm->lock);
+
+	return err;
 }
 EXPORT_SYMBOL_GPL(pwm_enable);
 
@@ -507,6 +563,9 @@ static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
  * lookup of the PWM index. This also means that the "pwm-names" property
  * becomes mandatory for devices that look up the PWM device via the con_id
  * parameter.
+ *
+ * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
+ * error code on failure.
  */
 struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
 {
@@ -585,6 +644,23 @@ void pwm_add_table(struct pwm_lookup *table, size_t num)
 	mutex_unlock(&pwm_lookup_lock);
 }
 
+/**
+ * pwm_remove_table() - unregister PWM device consumers
+ * @table: array of consumers to unregister
+ * @num: number of consumers in table
+ */
+void pwm_remove_table(struct pwm_lookup *table, size_t num)
+{
+	mutex_lock(&pwm_lookup_lock);
+
+	while (num--) {
+		list_del(&table->list);
+		table++;
+	}
+
+	mutex_unlock(&pwm_lookup_lock);
+}
+
 /**
  * pwm_get() - look up and request a PWM device
  * @dev: device for PWM consumer
@@ -596,6 +672,9 @@ void pwm_add_table(struct pwm_lookup *table, size_t num)
  *
  * Once a PWM chip has been found the specified PWM device will be requested
  * and is ready to be used.
+ *
+ * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
+ * error code on failure.
  */
 struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 {
@@ -659,8 +738,10 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 		}
 	}
 
-	if (!chosen)
+	if (!chosen) {
+		pwm = ERR_PTR(-ENODEV);
 		goto out;
+	}
 
 	chip = pwmchip_find_by_name(chosen->provider);
 	if (!chip)
@@ -718,6 +799,9 @@ static void devm_pwm_release(struct device *dev, void *res)
  *
  * This function performs like pwm_get() but the acquired PWM device will
  * automatically be released on driver detach.
+ *
+ * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
+ * error code on failure.
  */
 struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
 {
@@ -747,6 +831,9 @@ EXPORT_SYMBOL_GPL(devm_pwm_get);
  *
  * This function performs like of_pwm_get() but the acquired PWM device will
  * automatically be released on driver detach.
+ *
+ * Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
+ * error code on failure.
  */
 struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
 				   const char *con_id)
@@ -798,7 +885,7 @@ EXPORT_SYMBOL_GPL(devm_pwm_put);
   * pwm_can_sleep() - report whether PWM access will sleep
   * @pwm: PWM device
   *
-  * It returns true if accessing the PWM can sleep, false otherwise.
+  * Returns: True if accessing the PWM can sleep, false otherwise.
   */
 bool pwm_can_sleep(struct pwm_device *pwm)
 {
@@ -819,7 +906,7 @@ static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
 		if (test_bit(PWMF_REQUESTED, &pwm->flags))
 			seq_puts(s, " requested");
 
-		if (test_bit(PWMF_ENABLED, &pwm->flags))
+		if (pwm_is_enabled(pwm))
 			seq_puts(s, " enabled");
 
 		seq_puts(s, "\n");
@@ -890,6 +977,5 @@ static int __init pwm_debugfs_init(void)
 
 	return 0;
 }
-
 subsys_initcall(pwm_debugfs_init);
 #endif /* CONFIG_DEBUG_FS */