projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 4c20386c DB |
1 | #ifndef _ASM_GENERIC_GPIO_H |
| 2 | #define _ASM_GENERIC_GPIO_H | |
| 3 | ||
| d2876d08 DB |
4 | #ifdef CONFIG_HAVE_GPIO_LIB |
| 5 | ||
| 6 | /* Platforms may implement their GPIO interface with library code, | |
| 7 | * at a small performance cost for non-inlined operations and some | |
| 8 | * extra memory (for code and for per-GPIO table entries). | |
| 9 | * | |
| 10 | * While the GPIO programming interface defines valid GPIO numbers | |
| 11 | * to be in the range 0..MAX_INT, this library restricts them to the | |
| 12 | * smaller range 0..ARCH_NR_GPIOS. | |
| 13 | */ | |
| 14 | ||
| 15 | #ifndef ARCH_NR_GPIOS | |
| 16 | #define ARCH_NR_GPIOS 256 | |
| 17 | #endif | |
| 18 | ||
| 19 | struct seq_file; | |
| 438d8908 | 20 | struct module; |
| d2876d08 DB |
21 | |
| 22 | /** | |
| 23 | * struct gpio_chip - abstract a GPIO controller | |
| 24 | * @label: for diagnostics | |
| 25 | * @direction_input: configures signal "offset" as input, or returns error | |
| 26 | * @get: returns value for signal "offset"; for output signals this | |
| 27 | * returns either the value actually sensed, or zero | |
| 28 | * @direction_output: configures signal "offset" as output, or returns error | |
| 29 | * @set: assigns output value for signal "offset" | |
| 30 | * @dbg_show: optional routine to show contents in debugfs; default code | |
| 31 | * will be used when this is omitted, but custom code can show extra | |
| 32 | * state (such as pullup/pulldown configuration). | |
| 33 | * @base: identifies the first GPIO number handled by this chip; or, if | |
| 34 | * negative during registration, requests dynamic ID allocation. | |
| 35 | * @ngpio: the number of GPIOs handled by this controller; the last GPIO | |
| 36 | * handled is (base + ngpio - 1). | |
| 37 | * @can_sleep: flag must be set iff get()/set() methods sleep, as they | |
| 38 | * must while accessing GPIO expander chips over I2C or SPI | |
| 39 | * | |
| 40 | * A gpio_chip can help platforms abstract various sources of GPIOs so | |
| 41 | * they can all be accessed through a common programing interface. | |
| 42 | * Example sources would be SOC controllers, FPGAs, multifunction | |
| 43 | * chips, dedicated GPIO expanders, and so on. | |
| 44 | * | |
| 45 | * Each chip controls a number of signals, identified in method calls | |
| 46 | * by "offset" values in the range 0..(@ngpio - 1). When those signals | |
| 47 | * are referenced through calls like gpio_get_value(gpio), the offset | |
| 48 | * is calculated by subtracting @base from the gpio number. | |
| 49 | */ | |
| 50 | struct gpio_chip { | |
| 51 | char *label; | |
| 438d8908 | 52 | struct module *owner; |
| d2876d08 DB |
53 | |
| 54 | int (*direction_input)(struct gpio_chip *chip, | |
| 55 | unsigned offset); | |
| 56 | int (*get)(struct gpio_chip *chip, | |
| 57 | unsigned offset); | |
| 58 | int (*direction_output)(struct gpio_chip *chip, | |
| 59 | unsigned offset, int value); | |
| 60 | void (*set)(struct gpio_chip *chip, | |
| 61 | unsigned offset, int value); | |
| 62 | void (*dbg_show)(struct seq_file *s, | |
| 63 | struct gpio_chip *chip); | |
| 64 | int base; | |
| 65 | u16 ngpio; | |
| 66 | unsigned can_sleep:1; | |
| 67 | }; | |
| 68 | ||
| 69 | extern const char *gpiochip_is_requested(struct gpio_chip *chip, | |
| 70 | unsigned offset); | |
| 71 | ||
| 72 | /* add/remove chips */ | |
| 73 | extern int gpiochip_add(struct gpio_chip *chip); | |
| 74 | extern int __must_check gpiochip_remove(struct gpio_chip *chip); | |
| 75 | ||
| 76 | ||
| 77 | /* Always use the library code for GPIO management calls, | |
| 78 | * or when sleeping may be involved. | |
| 79 | */ | |
| 80 | extern int gpio_request(unsigned gpio, const char *label); | |
| 81 | extern void gpio_free(unsigned gpio); | |
| 82 | ||
| 83 | extern int gpio_direction_input(unsigned gpio); | |
| 84 | extern int gpio_direction_output(unsigned gpio, int value); | |
| 85 | ||
| 86 | extern int gpio_get_value_cansleep(unsigned gpio); | |
| 87 | extern void gpio_set_value_cansleep(unsigned gpio, int value); | |
| 88 | ||
| 89 | ||
| 90 | /* A platform's <asm/gpio.h> code may want to inline the I/O calls when | |
| 91 | * the GPIO is constant and refers to some always-present controller, | |
| 92 | * giving direct access to chip registers and tight bitbanging loops. | |
| 93 | */ | |
| 94 | extern int __gpio_get_value(unsigned gpio); | |
| 95 | extern void __gpio_set_value(unsigned gpio, int value); | |
| 96 | ||
| 97 | extern int __gpio_cansleep(unsigned gpio); | |
| 98 | ||
| 99 | ||
| 100 | #else | |
| 101 | ||
| 4c20386c DB |
102 | /* platforms that don't directly support access to GPIOs through I2C, SPI, |
| 103 | * or other blocking infrastructure can use these wrappers. | |
| 104 | */ | |
| 105 | ||
| 106 | static inline int gpio_cansleep(unsigned gpio) | |
| 107 | { | |
| 108 | return 0; | |
| 109 | } | |
| 110 | ||
| 111 | static inline int gpio_get_value_cansleep(unsigned gpio) | |
| 112 | { | |
| 113 | might_sleep(); | |
| 114 | return gpio_get_value(gpio); | |
| 115 | } | |
| 116 | ||
| 117 | static inline void gpio_set_value_cansleep(unsigned gpio, int value) | |
| 118 | { | |
| 119 | might_sleep(); | |
| 120 | gpio_set_value(gpio, value); | |
| 121 | } | |
| 122 | ||
| d2876d08 DB |
123 | #endif |
| 124 | ||
| 4c20386c | 125 | #endif /* _ASM_GENERIC_GPIO_H */ |