gpiolib: export descriptor-based GPIO interface
This patch exports the gpiod_* family of API functions, a safer alternative to the legacy GPIO interface. Differences between the gpiod and legacy gpio APIs are: - gpio works with integers, whereas gpiod operates on opaque handlers which cannot be forged or used before proper acquisition - gpiod get/set functions are aware of the active low state of a GPIO - gpio consumers should now include <linux/gpio/consumer.h> to access the new interface, whereas chips drivers will use <linux/gpio/driver.h> The legacy gpio API is now built as inline functions on top of gpiod. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Alexandre Courbot
committed by
Linus Walleij
Linus Walleij
parent
b41fb43911
commit
79a9becda8
@@ -10,6 +10,8 @@
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#ifdef CONFIG_GPIOLIB
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#include <linux/compiler.h>
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#include <linux/gpio/driver.h>
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#include <linux/gpio/consumer.h>
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/* Platforms may implement their GPIO interface with library code,
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* at a small performance cost for non-inlined operations and some
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@@ -49,122 +51,11 @@ struct module;
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struct device_node;
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struct gpio_desc;
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/**
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* struct gpio_chip - abstract a GPIO controller
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* @label: for diagnostics
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* @dev: optional device providing the GPIOs
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* @owner: helps prevent removal of modules exporting active GPIOs
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* @list: links gpio_chips together for traversal
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* @request: optional hook for chip-specific activation, such as
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* enabling module power and clock; may sleep
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* @free: optional hook for chip-specific deactivation, such as
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* disabling module power and clock; may sleep
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* @get_direction: returns direction for signal "offset", 0=out, 1=in,
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* (same as GPIOF_DIR_XXX), or negative error
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* @direction_input: configures signal "offset" as input, or returns error
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* @get: returns value for signal "offset"; for output signals this
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* returns either the value actually sensed, or zero
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* @direction_output: configures signal "offset" as output, or returns error
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* @set_debounce: optional hook for setting debounce time for specified gpio in
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* interrupt triggered gpio chips
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* @set: assigns output value for signal "offset"
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* @to_irq: optional hook supporting non-static gpio_to_irq() mappings;
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* implementation may not sleep
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* @dbg_show: optional routine to show contents in debugfs; default code
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* will be used when this is omitted, but custom code can show extra
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* state (such as pullup/pulldown configuration).
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* @base: identifies the first GPIO number handled by this chip; or, if
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* negative during registration, requests dynamic ID allocation.
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* @ngpio: the number of GPIOs handled by this controller; the last GPIO
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* handled is (base + ngpio - 1).
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* @desc: array of ngpio descriptors. Private.
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* @can_sleep: flag must be set iff get()/set() methods sleep, as they
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* must while accessing GPIO expander chips over I2C or SPI
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* @names: if set, must be an array of strings to use as alternative
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* names for the GPIOs in this chip. Any entry in the array
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* may be NULL if there is no alias for the GPIO, however the
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* array must be @ngpio entries long. A name can include a single printk
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* format specifier for an unsigned int. It is substituted by the actual
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* number of the gpio.
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*
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* A gpio_chip can help platforms abstract various sources of GPIOs so
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* they can all be accessed through a common programing interface.
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* Example sources would be SOC controllers, FPGAs, multifunction
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* chips, dedicated GPIO expanders, and so on.
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*
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* Each chip controls a number of signals, identified in method calls
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* by "offset" values in the range 0..(@ngpio - 1). When those signals
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* are referenced through calls like gpio_get_value(gpio), the offset
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* is calculated by subtracting @base from the gpio number.
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*/
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struct gpio_chip {
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const char *label;
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struct device *dev;
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struct module *owner;
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struct list_head list;
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int (*request)(struct gpio_chip *chip,
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unsigned offset);
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void (*free)(struct gpio_chip *chip,
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unsigned offset);
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int (*get_direction)(struct gpio_chip *chip,
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unsigned offset);
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int (*direction_input)(struct gpio_chip *chip,
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unsigned offset);
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int (*get)(struct gpio_chip *chip,
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unsigned offset);
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int (*direction_output)(struct gpio_chip *chip,
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unsigned offset, int value);
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int (*set_debounce)(struct gpio_chip *chip,
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unsigned offset, unsigned debounce);
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void (*set)(struct gpio_chip *chip,
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unsigned offset, int value);
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int (*to_irq)(struct gpio_chip *chip,
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unsigned offset);
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void (*dbg_show)(struct seq_file *s,
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struct gpio_chip *chip);
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int base;
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u16 ngpio;
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struct gpio_desc *desc;
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const char *const *names;
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unsigned can_sleep:1;
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unsigned exported:1;
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#if defined(CONFIG_OF_GPIO)
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/*
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* If CONFIG_OF is enabled, then all GPIO controllers described in the
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* device tree automatically may have an OF translation
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*/
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struct device_node *of_node;
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int of_gpio_n_cells;
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int (*of_xlate)(struct gpio_chip *gc,
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const struct of_phandle_args *gpiospec, u32 *flags);
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#endif
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#ifdef CONFIG_PINCTRL
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/*
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* If CONFIG_PINCTRL is enabled, then gpio controllers can optionally
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* describe the actual pin range which they serve in an SoC. This
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* information would be used by pinctrl subsystem to configure
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* corresponding pins for gpio usage.
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*/
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struct list_head pin_ranges;
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#endif
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};
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extern const char *gpiochip_is_requested(struct gpio_chip *chip,
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unsigned offset);
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extern struct gpio_chip *gpio_to_chip(unsigned gpio);
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/* add/remove chips */
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extern int gpiochip_add(struct gpio_chip *chip);
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extern int __must_check gpiochip_remove(struct gpio_chip *chip);
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extern struct gpio_chip *gpiochip_find(void *data,
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int (*match)(struct gpio_chip *chip,
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void *data));
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/* caller holds gpio_lock *OR* gpio is marked as requested */
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static inline struct gpio_chip *gpio_to_chip(unsigned gpio)
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{
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return gpiod_to_chip(gpio_to_desc(gpio));
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}
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/* Always use the library code for GPIO management calls,
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* or when sleeping may be involved.
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@@ -172,25 +63,52 @@ extern struct gpio_chip *gpiochip_find(void *data,
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extern int gpio_request(unsigned gpio, const char *label);
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extern void gpio_free(unsigned gpio);
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extern int gpio_direction_input(unsigned gpio);
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extern int gpio_direction_output(unsigned gpio, int value);
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static inline int gpio_direction_input(unsigned gpio)
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{
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return gpiod_direction_input(gpio_to_desc(gpio));
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}
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static inline int gpio_direction_output(unsigned gpio, int value)
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{
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return gpiod_direction_output(gpio_to_desc(gpio), value);
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}
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extern int gpio_set_debounce(unsigned gpio, unsigned debounce);
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static inline int gpio_set_debounce(unsigned gpio, unsigned debounce)
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{
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return gpiod_set_debounce(gpio_to_desc(gpio), debounce);
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}
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extern int gpio_get_value_cansleep(unsigned gpio);
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extern void gpio_set_value_cansleep(unsigned gpio, int value);
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static inline int gpio_get_value_cansleep(unsigned gpio)
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{
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return gpiod_get_raw_value_cansleep(gpio_to_desc(gpio));
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}
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static inline void gpio_set_value_cansleep(unsigned gpio, int value)
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{
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return gpiod_set_raw_value_cansleep(gpio_to_desc(gpio), value);
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}
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/* A platform's <asm/gpio.h> code may want to inline the I/O calls when
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* the GPIO is constant and refers to some always-present controller,
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* giving direct access to chip registers and tight bitbanging loops.
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*/
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extern int __gpio_get_value(unsigned gpio);
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extern void __gpio_set_value(unsigned gpio, int value);
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static inline int __gpio_get_value(unsigned gpio)
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{
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return gpiod_get_raw_value(gpio_to_desc(gpio));
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}
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static inline void __gpio_set_value(unsigned gpio, int value)
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{
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return gpiod_set_raw_value(gpio_to_desc(gpio), value);
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}
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extern int __gpio_cansleep(unsigned gpio);
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static inline int __gpio_cansleep(unsigned gpio)
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{
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return gpiod_cansleep(gpio_to_desc(gpio));
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}
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extern int __gpio_to_irq(unsigned gpio);
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static inline int __gpio_to_irq(unsigned gpio)
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{
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return gpiod_to_irq(gpio_to_desc(gpio));
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}
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extern int gpio_lock_as_irq(struct gpio_chip *chip, unsigned int offset);
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extern void gpio_unlock_as_irq(struct gpio_chip *chip, unsigned int offset);
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@@ -199,19 +117,30 @@ extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *labe
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extern int gpio_request_array(const struct gpio *array, size_t num);
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extern void gpio_free_array(const struct gpio *array, size_t num);
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#ifdef CONFIG_GPIO_SYSFS
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/*
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* A sysfs interface can be exported by individual drivers if they want,
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* but more typically is configured entirely from userspace.
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*/
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extern int gpio_export(unsigned gpio, bool direction_may_change);
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extern int gpio_export_link(struct device *dev, const char *name,
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unsigned gpio);
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extern int gpio_sysfs_set_active_low(unsigned gpio, int value);
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extern void gpio_unexport(unsigned gpio);
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static inline int gpio_export(unsigned gpio, bool direction_may_change)
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{
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return gpiod_export(gpio_to_desc(gpio), direction_may_change);
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}
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#endif /* CONFIG_GPIO_SYSFS */
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static inline int gpio_export_link(struct device *dev, const char *name,
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unsigned gpio)
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{
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return gpiod_export_link(dev, name, gpio_to_desc(gpio));
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}
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static inline int gpio_sysfs_set_active_low(unsigned gpio, int value)
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{
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return gpiod_sysfs_set_active_low(gpio_to_desc(gpio), value);
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}
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static inline void gpio_unexport(unsigned gpio)
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{
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gpiod_unexport(gpio_to_desc(gpio));
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}
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#ifdef CONFIG_PINCTRL
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@@ -281,31 +210,4 @@ static inline void gpio_set_value_cansleep(unsigned gpio, int value)
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#endif /* !CONFIG_GPIOLIB */
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#ifndef CONFIG_GPIO_SYSFS
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struct device;
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/* sysfs support is only available with gpiolib, where it's optional */
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static inline int gpio_export(unsigned gpio, bool direction_may_change)
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{
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return -ENOSYS;
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}
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static inline int gpio_export_link(struct device *dev, const char *name,
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unsigned gpio)
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{
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return -ENOSYS;
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}
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static inline int gpio_sysfs_set_active_low(unsigned gpio, int value)
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{
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return -ENOSYS;
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}
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static inline void gpio_unexport(unsigned gpio)
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{
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}
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#endif /* CONFIG_GPIO_SYSFS */
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#endif /* _ASM_GENERIC_GPIO_H */
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