pinctrl: implement devm_pinctrl_get()/put()

These functions allow the driver core to automatically clean up any
allocations made by drivers, thus leading to simplified drivers.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Stephen Warren 2012-04-16 10:51:00 -06:00 committed by Linus Walleij
parent 2aeefe0233
commit 6d4ca1fb46
4 changed files with 133 additions and 19 deletions

View File

@ -276,3 +276,7 @@ REGULATOR
devm_regulator_get()
devm_regulator_put()
devm_regulator_bulk_get()
PINCTRL
devm_pinctrl_get()
devm_pinctrl_put()

View File

@ -945,13 +945,13 @@ case), we define a mapping like this:
The result of grabbing this mapping from the device with something like
this (see next paragraph):
p = pinctrl_get(dev);
p = devm_pinctrl_get(dev);
s = pinctrl_lookup_state(p, "8bit");
ret = pinctrl_select_state(p, s);
or more simply:
p = pinctrl_get_select(dev, "8bit");
p = devm_pinctrl_get_select(dev, "8bit");
Will be that you activate all the three bottom records in the mapping at
once. Since they share the same name, pin controller device, function and
@ -985,7 +985,7 @@ foo_probe()
/* Allocate a state holder named "foo" etc */
struct foo_state *foo = ...;
foo->p = pinctrl_get(&device);
foo->p = devm_pinctrl_get(&device);
if (IS_ERR(foo->p)) {
/* FIXME: clean up "foo" here */
return PTR_ERR(foo->p);
@ -993,24 +993,17 @@ foo_probe()
foo->s = pinctrl_lookup_state(foo->p, PINCTRL_STATE_DEFAULT);
if (IS_ERR(foo->s)) {
pinctrl_put(foo->p);
/* FIXME: clean up "foo" here */
return PTR_ERR(s);
}
ret = pinctrl_select_state(foo->s);
if (ret < 0) {
pinctrl_put(foo->p);
/* FIXME: clean up "foo" here */
return ret;
}
}
foo_remove()
{
pinctrl_put(state->p);
}
This get/lookup/select/put sequence can just as well be handled by bus drivers
if you don't want each and every driver to handle it and you know the
arrangement on your bus.
@ -1022,6 +1015,11 @@ The semantics of the pinctrl APIs are:
kernel memory to hold the pinmux state. All mapping table parsing or similar
slow operations take place within this API.
- devm_pinctrl_get() is a variant of pinctrl_get() that causes pinctrl_put()
to be called automatically on the retrieved pointer when the associated
device is removed. It is recommended to use this function over plain
pinctrl_get().
- pinctrl_lookup_state() is called in process context to obtain a handle to a
specific state for a the client device. This operation may be slow too.
@ -1034,14 +1032,25 @@ The semantics of the pinctrl APIs are:
- pinctrl_put() frees all information associated with a pinctrl handle.
- devm_pinctrl_put() is a variant of pinctrl_put() that may be used to
explicitly destroy a pinctrl object returned by devm_pinctrl_get().
However, use of this function will be rare, due to the automatic cleanup
that will occur even without calling it.
pinctrl_get() must be paired with a plain pinctrl_put().
pinctrl_get() may not be paired with devm_pinctrl_put().
devm_pinctrl_get() can optionally be paired with devm_pinctrl_put().
devm_pinctrl_get() may not be paired with plain pinctrl_put().
Usually the pin control core handled the get/put pair and call out to the
device drivers bookkeeping operations, like checking available functions and
the associated pins, whereas the enable/disable pass on to the pin controller
driver which takes care of activating and/or deactivating the mux setting by
quickly poking some registers.
The pins are allocated for your device when you issue the pinctrl_get() call,
after this you should be able to see this in the debugfs listing of all pins.
The pins are allocated for your device when you issue the devm_pinctrl_get()
call, after this you should be able to see this in the debugfs listing of all
pins.
NOTE: the pinctrl system will return -EPROBE_DEFER if it cannot find the
requested pinctrl handles, for example if the pinctrl driver has not yet
@ -1092,13 +1101,13 @@ it, disables and releases it, and muxes it in on the pins defined by group B:
#include <linux/pinctrl/consumer.h>
foo_switch()
{
struct pinctrl *p;
struct pinctrl_state *s1, *s2;
struct pinctrl *p;
struct pinctrl_state *s1, *s2;
foo_probe()
{
/* Setup */
p = pinctrl_get(&device);
p = devm_pinctrl_get(&device);
if (IS_ERR(p))
...
@ -1109,7 +1118,10 @@ foo_switch()
s2 = pinctrl_lookup_state(foo->p, "pos-B");
if (IS_ERR(s2))
...
}
foo_switch()
{
/* Enable on position A */
ret = pinctrl_select_state(s1);
if (ret < 0)
@ -1123,8 +1135,6 @@ foo_switch()
...
...
pinctrl_put(p);
}
The above has to be done from process context.

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@ -23,6 +23,7 @@
#include <linux/sysfs.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/pinctrl/consumer.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/machine.h>
#include "core.h"
@ -801,6 +802,61 @@ int pinctrl_select_state(struct pinctrl *p, struct pinctrl_state *state)
}
EXPORT_SYMBOL_GPL(pinctrl_select_state);
static void devm_pinctrl_release(struct device *dev, void *res)
{
pinctrl_put(*(struct pinctrl **)res);
}
/**
* struct devm_pinctrl_get() - Resource managed pinctrl_get()
* @dev: the device to obtain the handle for
*
* If there is a need to explicitly destroy the returned struct pinctrl,
* devm_pinctrl_put() should be used, rather than plain pinctrl_put().
*/
struct pinctrl *devm_pinctrl_get(struct device *dev)
{
struct pinctrl **ptr, *p;
ptr = devres_alloc(devm_pinctrl_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
p = pinctrl_get(dev);
if (!IS_ERR(p)) {
*ptr = p;
devres_add(dev, ptr);
} else {
devres_free(ptr);
}
return p;
}
EXPORT_SYMBOL_GPL(devm_pinctrl_get);
static int devm_pinctrl_match(struct device *dev, void *res, void *data)
{
struct pinctrl **p = res;
return *p == data;
}
/**
* devm_pinctrl_put() - Resource managed pinctrl_put()
* @p: the pinctrl handle to release
*
* Deallocate a struct pinctrl obtained via devm_pinctrl_get(). Normally
* this function will not need to be called and the resource management
* code will ensure that the resource is freed.
*/
void devm_pinctrl_put(struct pinctrl *p)
{
WARN_ON(devres_destroy(p->dev, devm_pinctrl_release,
devm_pinctrl_match, p));
pinctrl_put(p);
}
EXPORT_SYMBOL_GPL(devm_pinctrl_put);
int pinctrl_register_map(struct pinctrl_map const *maps, unsigned num_maps,
bool dup, bool locked)
{

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@ -36,6 +36,9 @@ extern struct pinctrl_state * __must_check pinctrl_lookup_state(
const char *name);
extern int pinctrl_select_state(struct pinctrl *p, struct pinctrl_state *s);
extern struct pinctrl * __must_check devm_pinctrl_get(struct device *dev);
extern void devm_pinctrl_put(struct pinctrl *p);
#else /* !CONFIG_PINCTRL */
static inline int pinctrl_request_gpio(unsigned gpio)
@ -79,6 +82,15 @@ static inline int pinctrl_select_state(struct pinctrl *p,
return 0;
}
static inline struct pinctrl * __must_check devm_pinctrl_get(struct device *dev)
{
return NULL;
}
static inline void devm_pinctrl_put(struct pinctrl *p)
{
}
#endif /* CONFIG_PINCTRL */
static inline struct pinctrl * __must_check pinctrl_get_select(
@ -113,6 +125,38 @@ static inline struct pinctrl * __must_check pinctrl_get_select_default(
return pinctrl_get_select(dev, PINCTRL_STATE_DEFAULT);
}
static inline struct pinctrl * __must_check devm_pinctrl_get_select(
struct device *dev, const char *name)
{
struct pinctrl *p;
struct pinctrl_state *s;
int ret;
p = devm_pinctrl_get(dev);
if (IS_ERR(p))
return p;
s = pinctrl_lookup_state(p, name);
if (IS_ERR(s)) {
devm_pinctrl_put(p);
return ERR_PTR(PTR_ERR(s));
}
ret = pinctrl_select_state(p, s);
if (ret < 0) {
devm_pinctrl_put(p);
return ERR_PTR(ret);
}
return p;
}
static inline struct pinctrl * __must_check devm_pinctrl_get_select_default(
struct device *dev)
{
return devm_pinctrl_get_select(dev, PINCTRL_STATE_DEFAULT);
}
#ifdef CONFIG_PINCONF
extern int pin_config_get(const char *dev_name, const char *name,