diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-generic/gpio.h | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h index f541039..e325df4 100644 --- a/include/asm-generic/gpio.h +++ b/include/asm-generic/gpio.h @@ -78,4 +78,108 @@ int gpio_get_value(unsigned gpio); * @return 0 if ok, -1 on error */ int gpio_set_value(unsigned gpio, int value); + +/* State of a GPIO, as reported by get_state() */ +enum { + GPIOF_INPUT = 0, + GPIOF_OUTPUT, + GPIOF_UNKNOWN, +}; + +struct device; + +/** + * struct struct dm_gpio_ops - Driver model GPIO operations + * + * Refer to functions above for description. These function largely copy + * the old API. + * + * This is trying to be close to Linux GPIO API. Once the U-Boot uses the + * new DM GPIO API, this should be really easy to flip over to the Linux + * GPIO API-alike interface. + * + * Akso it would be useful to standardise additional functions like + * pullup, slew rate and drive strength. + * + * gpio_request)( and gpio_free() are optional - if NULL then they will + * not be called. + * + * Note that @offset is the offset from the base GPIO of the device. So + * offset 0 is the device's first GPIO and offset o-1 is the last GPIO, + * where o is the number of GPIO lines controlled by the device. A device + * is typically used to control a single bank of GPIOs. Within complex + * SoCs there may be many banks and therefore many devices all referring + * to the different IO addresses within the SoC. + * + * The uclass combines all GPIO devices togther to provide a consistent + * numbering from 0 to n-1, where n is the number of GPIOs in total across + * all devices. Be careful not to confuse offset with gpio in the parameters. + */ +struct dm_gpio_ops { + int (*request)(struct device *dev, unsigned offset, const char *label); + int (*free)(struct device *dev, unsigned offset); + int (*direction_input)(struct device *dev, unsigned offset); + int (*direction_output)(struct device *dev, unsigned offset, + int value); + int (*get_value)(struct device *dev, unsigned offset); + int (*set_value)(struct device *dev, unsigned offset, int value); + int (*get_function)(struct device *dev, unsigned offset); + int (*get_state)(struct device *dev, unsigned offset, char *state, + int maxlen); +}; + +/** + * struct gpio_dev_priv - information about a device used by the uclass + * + * The uclass combines all active GPIO devices into a unified numbering + * scheme. To do this it maintains some private information aobut each + * device. + * + * To implement driver model support in your GPIO driver, add a probe + * handler, and set @gpio_count and @bank_name correctly in that handler. + * This tells the uclass the name of the GPIO bank and the number of GPIOs + * it contains. + * + * @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called + * 'A0', 'A1', etc. + * @gpio_count: Number of GPIOs in this device + * @gpio_base: Base GPIO number for this device. For the first active device + * this will be 0; the numbering for others will follow sequentially so that + * @gpio_base for device 1 will equal the number of GPIOs in device 0. + */ +struct gpio_dev_priv { + const char *bank_name; + unsigned gpio_count; + unsigned gpio_base; +}; + +/* Access the GPIO operations for a device */ +#define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops) + +/** + * gpio_get_bank_info - Return information about a GPIO bank/device + * + * This looks up a device and returns both its GPIO base name and the number + * of GPIOs it controls. + * + * @dev: Device to look up + * @offset_count: Returns number of GPIOs within this bank + * @return bank name of this device + */ +const char *gpio_get_bank_info(struct device *dev, int *offset_count); + +/** + * gpio_lookup_name - Look up a GPIO name and return its details + * + * This is used to convert a named GPIO into a device, offset and GPIO + * number. + * + * @name: GPIO name to look up + * @devp: Returns pointer to device which contains this GPIO + * @offsetp: Returns the offset number within this device + * @gpiop: Returns the absolute GPIO number, numbered from 0 + */ +int gpio_lookup_name(const char *name, struct device **devp, + unsigned int *offsetp, unsigned int *gpiop); + #endif /* _ASM_GENERIC_GPIO_H_ */ |