pwm: Clean up kerneldoc

Clean up kerneldoc in preparation for including the PWM documentation in
DocBook.

Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

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)
 {
@@ -230,6 +234,8 @@ EXPORT_SYMBOL_GPL(pwm_get_chip_data);
  * Register a new PWM chip. If chip->base < 0 then a dynamically assigned base
  * 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_with_polarity(struct pwm_chip *chip,
 			      enum pwm_polarity polarity)
@@ -291,6 +297,8 @@ EXPORT_SYMBOL_GPL(pwmchip_add_with_polarity);
  *
  * 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)
 {
@@ -304,6 +312,8 @@ 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)
 {
@@ -338,10 +348,13 @@ 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)
 {
@@ -376,9 +389,9 @@ 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
+ * Returns: A pointer to the PWM device at the given index of the given PWM
- * code is returned if the index is not valid for the specified PWM chip or
+ * chip. A negative error code is returned if the index is not valid for the
- * if the PWM device cannot be requested.
+ * 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,
@@ -419,6 +432,8 @@ 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)
 {
@@ -443,7 +458,10 @@ 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)
 {
@@ -471,6 +489,8 @@ 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)
 {
@@ -524,6 +544,9 @@ 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)
 {
@@ -630,6 +653,9 @@ void pwm_remove_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)
 {
@@ -752,6 +778,9 @@ 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)
 {
@@ -781,6 +810,9 @@ 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)
@@ -832,7 +864,7 @@ 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)
 {

include/linux/pwm.h

@@ -79,6 +79,18 @@ enum {
 	PWMF_EXPORTED = 1 << 2,
 };
 
+/**
+ * struct pwm_device - PWM channel object
+ * @label: name of the PWM device
+ * @flags: flags associated with the PWM device
+ * @hwpwm: per-chip relative index of the PWM device
+ * @pwm: global index of the PWM device
+ * @chip: PWM chip providing this PWM device
+ * @chip_data: chip-private data associated with the PWM device
+ * @period: period of the PWM signal (in nanoseconds)
+ * @duty_cycle: duty cycle of the PWM signal (in nanoseconds)
+ * @polarity: polarity of the PWM signal
+ */
 struct pwm_device {
 	const char *label;
 	unsigned long flags;
@@ -163,6 +175,8 @@ struct pwm_ops {
  * @base: number of first PWM controlled by this chip
  * @npwm: number of PWMs controlled by this chip
  * @pwms: array of PWM devices allocated by the framework
+ * @of_xlate: request a PWM device given a device tree PWM specifier
+ * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier
  * @can_sleep: must be true if the .config(), .enable() or .disable()
  *             operations may sleep
  */