diff options
| -rw-r--r-- | Documentation/driver-model/devres.txt | 4 | ||||
| -rw-r--r-- | Documentation/pinctrl.txt | 48 | ||||
| -rw-r--r-- | drivers/pinctrl/core.c | 56 | ||||
| -rw-r--r-- | include/linux/pinctrl/consumer.h | 44 |
4 files changed, 133 insertions, 19 deletions
diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt index 2a596a4..ef4fa7b 100644 --- a/Documentation/driver-model/devres.txt +++ b/Documentation/driver-model/devres.txt @@ -276,3 +276,7 @@ REGULATOR devm_regulator_get() devm_regulator_put() devm_regulator_bulk_get() + +PINCTRL + devm_pinctrl_get() + devm_pinctrl_put() diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt index 4431c3e7..e40f4b4 100644 --- a/Documentation/pinctrl.txt +++ b/Documentation/pinctrl.txt @@ -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. diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c index 59027ab..2eaa187 100644 --- a/drivers/pinctrl/core.c +++ b/drivers/pinctrl/core.c @@ -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) { diff --git a/include/linux/pinctrl/consumer.h b/include/linux/pinctrl/consumer.h index 191e726..6dd96fb 100644 --- a/include/linux/pinctrl/consumer.h +++ b/include/linux/pinctrl/consumer.h @@ -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, |
