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Date: Wed, 1 Aug 2012 19:20:58 +0900
From: Alexandre Courbot <acourbot@...dia.com>
To: Thierry Reding <thierry.reding@...onic-design.de>
CC: <linux-kernel@...r.kernel.org>,
Alexandre Courbot <acourbot@...dia.com>
Subject: [PATCH v2] pwm: add devm_pwm_get() and devm_pwm_put()
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@...dia.com>
---
Documentation/driver-model/devres.txt | 4 +++
Documentation/pwm.txt | 3 +-
drivers/pwm/core.c | 68 +++++++++++++++++++++++++++++++++++
include/linux/pwm.h | 3 ++
4 files changed, 77 insertions(+), 1 deletion(-)
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..47cd24d 100644
--- a/Documentation/pwm.txt
+++ b/Documentation/pwm.txt
@@ -36,7 +36,8 @@ 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.
+device or a consumer name. pwm_put() is used to free the PWM device. Devm
+variants of these functions also exist.
After being requested a PWM has to be configured using:
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index ecb7690..62315d7 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -624,6 +624,74 @@ 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()
+ * @dev: device for PWM consumer
+ * @con_id: consumer name
+ *
+ * This function performs like pwm_get() but the acquired PWM device will
+ * automatically be released on driver detach.
+ *
+ * Lookup is first attempted using DT. If the device was not instantiated from
+ * a device tree, a PWM chip and a relative index is looked up via a table
+ * supplied by board setup code (see pwm_add_table()).
+ *
+ * Once a PWM chip has been found the specified PWM device will be requested
+ * and is ready to be used.
+ */
+struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id)
+{
+ 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, con_id);
+ 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()
+ * @dev: device for PWM consumer
+ * @pwm: PWM device
+ *
+ * Release a PWM previously allocated using devm_pwm_get. Calling this function
+ * is usually not needed as devm-allocated resources are automatically 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..8ddc824 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -125,6 +125,9 @@ struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
struct pwm_device *pwm_get(struct device *dev, const char *consumer);
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);
+
struct pwm_lookup {
struct list_head list;
const char *provider;
--
1.7.11.3
--
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