On Wed 01 Aug 2012 05:04:53 PM JST, Thierry Reding wrote:
* PGP Signed by an unknown key
On Wed, Aug 01, 2012 at 04:37:09PM +0900, Alexandre Courbot wrote:
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 <acour...@nvidia.com>
---
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.
I think I'd prefer the original text with an additional line mentioning
the managed variants.
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 is missing parameter descriptions here.
This is because the documentation for this function just refers to
pwm_get(), and the parameters are the same. I think it's better to avoid
duplicating documentation as much as possible as this makes two
maintenance points instead of one.
+ *
+ * This works are pwm_get() but the acquired pwm will automatically be released
"works like"? Also "acquired PWM" or "acquired PWM device".
Ooops, yes. I really should proof-read what I write. Twice.
+ * 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.
+ */
Same comments as for devm_pwm_get().
+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);
Can the managed variants be grouped together, please?
Sure.
Thanks,
Alex.
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