[PATCH] pwm: add devm_pwm_get() and devm_pwm_put()

[Alexandre Courbot]

Add resource managed variants of pwm_get() and pwm_put() for
convenience. Code is largely inspired by the equivalent devm functions
of the regulator framework.

Signed-off-by: Alexandre Courbot <acourbot@xxxxxxxxxx>
---
 Documentation/driver-model/devres.txt |  4 +++
 Documentation/pwm.txt                 |  5 +--
 drivers/pwm/core.c                    | 57 +++++++++++++++++++++++++++++++++++
 include/linux/pwm.h                   |  3 ++
 4 files changed, 67 insertions(+), 2 deletions(-)

diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index 950856b..43cff70 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -284,3 +284,7 @@ CLOCK
 PINCTRL
   devm_pinctrl_get()
   devm_pinctrl_put()
+
+PWM
+  devm_pwm_get()
+  devm_pwm_put()
diff --git a/Documentation/pwm.txt b/Documentation/pwm.txt
index 554290e..4719c12 100644
--- a/Documentation/pwm.txt
+++ b/Documentation/pwm.txt
@@ -35,8 +35,9 @@ Using PWMs
 Legacy users can request a PWM device using pwm_request() and free it
 after usage with pwm_free().
 
-New users should use the pwm_get() function and pass to it the consumer
-device or a consumer name. pwm_put() is used to free the PWM device.
+New users should use the pwm_get() or devm_pwm_get() function and pass to it the
+consumer device or a consumer name. pwm_put() or devm_pwm_put() is used to free
+the PWM device.
 
 After being requested a PWM has to be configured using:
 
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index ecb7690..5a5e19b 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -624,6 +624,63 @@ out:
 }
 EXPORT_SYMBOL_GPL(pwm_put);
 
+static void devm_pwm_release(struct device *dev, void *res)
+{
+	pwm_put(*(struct pwm_device **)res);
+}
+
+/**
+ * devm_pwm_get() - Resource managed pwm_get()
+ *
+ * This works are pwm_get() but the acquired pwm will automatically be released
+ * on driver detach. See pwm_get() for more details.
+ */
+struct pwm_device *devm_pwm_get(struct device *dev, const char *consumer)
+{
+	struct pwm_device **ptr, *pwm;
+
+	ptr = devres_alloc(devm_pwm_release, sizeof(**ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	pwm = pwm_get(dev, consumer);
+	if (!IS_ERR(pwm)) {
+		*ptr = pwm;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return pwm;
+}
+EXPORT_SYMBOL_GPL(devm_pwm_get);
+
+static int devm_pwm_match(struct device *dev, void *res, void *data)
+{
+	struct pwm_device **p = res;
+
+	if (WARN_ON(!p || !*p))
+		return 0;
+
+	return *p == data;
+}
+
+/**
+ * devm_pwm_put() - Resource managed pwm_put()
+ *
+ * Releases a pwm previously allocated using devm_pwm_get. Calling this function
+ * is usually not needed as the devm-allocated pwm will automatically be
+ * released on driver detach.
+ */
+void devm_pwm_put(struct device *dev, struct pwm_device *pwm)
+{
+	int ret;
+
+	ret = devres_release(dev, devm_pwm_release, devm_pwm_match, pwm);
+	WARN_ON(ret);
+}
+EXPORT_SYMBOL_GPL(devm_pwm_put);
+
 #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 21d076c..af9c39a 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -123,7 +123,10 @@ struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
 					 const char *label);
 
 struct pwm_device *pwm_get(struct device *dev, const char *consumer);
+struct pwm_device *devm_pwm_get(struct device *dev, const char *consumer);
+
 void pwm_put(struct pwm_device *pwm);
+void devm_pwm_put(struct device *dev, struct pwm_device *pwm);
 
 struct pwm_lookup {
 	struct list_head list;
-- 
1.7.11.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/