pwm: Add pwm_can_sleep() as exported API to users

Calls to some external PWM chips can sleep. To help users,
add pwm_can_sleep() API.

Cc: Thierry Reding <thierry.reding@avionic-design.de>
Cc: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Florian Vaussard <florian.vaussard@epfl.ch>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 903138b18842d5fb94cdc88316419702f7e0ae8c..ffbef95e88dceb1f079cbd93e4a81a3cac77e6f9 100644 (file)
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -733,6 +733,18 @@ void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
 }
 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.
+  */
+bool pwm_can_sleep(struct pwm_device *pwm)
+{
+       return pwm->chip->can_sleep;
+}
+EXPORT_SYMBOL_GPL(pwm_can_sleep);
+
 #ifdef CONFIG_DEBUG_FS
 static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
 {

diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 6d661f32e0e4675681cf8fd3b1284e6a684b6dbe..3fef47733ea3a4a536cb87f053dc002ca20c1c0c 100644 (file)
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -146,6 +146,8 @@ 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
+ * @can_sleep: must be true if the .config(), .enable() or .disable()
+ *             operations may sleep
  */
 struct pwm_chip {
        struct device           *dev;
@@ -159,6 +161,7 @@ struct pwm_chip {
        struct pwm_device *     (*of_xlate)(struct pwm_chip *pc,
                                            const struct of_phandle_args *args);
        unsigned int            of_pwm_n_cells;
+       bool                    can_sleep;
 };
 
 #if IS_ENABLED(CONFIG_PWM)
@@ -179,6 +182,8 @@ void pwm_put(struct pwm_device *pwm);
 
 struct pwm_device *devm_pwm_get(struct device *dev, const char *consumer);
 void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
+
+bool pwm_can_sleep(struct pwm_device *pwm);
 #else
 static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data)
 {
@@ -226,6 +231,11 @@ static inline struct pwm_device *devm_pwm_get(struct device *dev,
 static inline void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
 {
 }
+
+static inline bool pwm_can_sleep(struct pwm_device *pwm)
+{
+       return false;
+}
 #endif
 
 struct pwm_lookup {