diff options
Diffstat (limited to 'include/asm-generic/gpio.h')
| -rw-r--r-- | include/asm-generic/gpio.h | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h index 36a36c64b8..3b96b8209a 100644 --- a/include/asm-generic/gpio.h +++ b/include/asm-generic/gpio.h @@ -10,6 +10,15 @@ /* * Generic GPIO API for U-Boot * + * -- + * NB: This is deprecated. Please use the driver model functions instead: + * + * - gpio_request_by_name() + * - dm_gpio_get_value() etc. + * + * For now we need a dm_ prefix on some functions to avoid name collision. + * -- + * * GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined * by the SOC/architecture. * @@ -26,6 +35,7 @@ */ /** + * @deprecated Please use driver model instead * Request a GPIO. This should be called before any of the other functions * are used on this GPIO. * @@ -39,6 +49,7 @@ int gpio_request(unsigned gpio, const char *label); /** + * @deprecated Please use driver model instead * Stop using the GPIO. This function should not alter pin configuration. * * @param gpio GPIO number @@ -47,6 +58,7 @@ int gpio_request(unsigned gpio, const char *label); int gpio_free(unsigned gpio); /** + * @deprecated Please use driver model instead * Make a GPIO an input. * * @param gpio GPIO number @@ -55,6 +67,7 @@ int gpio_free(unsigned gpio); int gpio_direction_input(unsigned gpio); /** + * @deprecated Please use driver model instead * Make a GPIO an output, and set its value. * * @param gpio GPIO number @@ -64,6 +77,7 @@ int gpio_direction_input(unsigned gpio); int gpio_direction_output(unsigned gpio, int value); /** + * @deprecated Please use driver model instead * Get a GPIO's value. This will work whether the GPIO is an input * or an output. * @@ -73,6 +87,7 @@ int gpio_direction_output(unsigned gpio, int value); int gpio_get_value(unsigned gpio); /** + * @deprecated Please use driver model instead * Set an output GPIO's value. The GPIO must already be an output or * this function may have no effect. * @@ -95,6 +110,34 @@ enum gpio_func_t { struct udevice; +struct gpio_desc { + struct udevice *dev; /* Device, NULL for invalid GPIO */ + unsigned long flags; +#define GPIOD_REQUESTED (1 << 0) /* Requested/claimed */ +#define GPIOD_IS_OUT (1 << 1) /* GPIO is an output */ +#define GPIOD_IS_IN (1 << 2) /* GPIO is an output */ +#define GPIOD_ACTIVE_LOW (1 << 3) /* value has active low */ +#define GPIOD_IS_OUT_ACTIVE (1 << 4) /* set output active */ + + uint offset; /* GPIO offset within the device */ + /* + * We could consider adding the GPIO label in here. Possibly we could + * use this structure for internal GPIO information. + */ +}; + +/** + * dm_gpio_is_valid() - Check if a GPIO is gpio_is_valie + * + * @desc: GPIO description containing device, offset and flags, + * previously returned by gpio_request_by_name() + * @return true if valid, false if not + */ +static inline bool dm_gpio_is_valid(struct gpio_desc *desc) +{ + return desc->dev != NULL; +} + /** * gpio_get_status() - get the current GPIO status as a string * @@ -106,6 +149,8 @@ struct udevice; * which means this is GPIO bank b, offset 4, currently set to input, current * value 1, [x] means that it is requested and the owner is 'sdmmc_cd' * + * TODO(sjg@chromium.org): This should use struct gpio_desc + * * @dev: Device to check * @offset: Offset of device GPIO to check * @buf: Place to put string @@ -118,6 +163,8 @@ int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize); * * Note this returns GPIOF_UNUSED if the GPIO is not requested. * + * TODO(sjg@chromium.org): This should use struct gpio_desc + * * @dev: Device to check * @offset: Offset of device GPIO to check * @namep: If non-NULL, this is set to the nane given when the GPIO @@ -135,6 +182,8 @@ int gpio_get_function(struct udevice *dev, int offset, const char **namep); * Note this does not return GPIOF_UNUSED - it will always return the GPIO * driver's view of a pin function, even if it is not correctly set up. * + * TODO(sjg@chromium.org): This should use struct gpio_desc + * * @dev: Device to check * @offset: Offset of device GPIO to check * @namep: If non-NULL, this is set to the nane given when the GPIO @@ -155,6 +204,8 @@ int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep); int gpio_requestf(unsigned gpio, const char *fmt, ...) __attribute__ ((format (__printf__, 2, 3))); +struct fdtdec_phandle_args; + /** * struct struct dm_gpio_ops - Driver model GPIO operations * @@ -198,6 +249,33 @@ struct dm_gpio_ops { * @return current function - GPIOF_... */ int (*get_function)(struct udevice *dev, unsigned offset); + + /** + * xlate() - Translate phandle arguments into a GPIO description + * + * This function should set up the fields in desc according to the + * information in the arguments. The uclass will have set up: + * + * @desc->dev to @dev + * @desc->flags to 0 + * @desc->offset to the value of the first argument in args, if any, + * otherwise -1 (which is invalid) + * + * This method is optional so if the above defaults suit it can be + * omitted. Typical behaviour is to set up the GPIOD_ACTIVE_LOW flag + * in desc->flags. + * + * Note that @dev is passed in as a parameter to follow driver model + * uclass conventions, even though it is already available as + * desc->dev. + * + * @dev: GPIO device + * @desc: Place to put GPIO description + * @args: Arguments provided in descripion + * @return 0 if OK, -ve on error + */ + int (*xlate)(struct udevice *dev, struct gpio_desc *desc, + struct fdtdec_phandle_args *args); }; /** @@ -268,4 +346,191 @@ int gpio_lookup_name(const char *name, struct udevice **devp, */ unsigned gpio_get_values_as_int(const int *gpio_list); +/** + * gpio_request_by_name() - Locate and request a GPIO by name + * + * This operates by looking up the given list name in the device (device + * tree property) and requesting the GPIO for use. The property must exist + * in @dev's node. + * + * Use @flags to specify whether the GPIO should be an input or output. In + * principle this can also come from the device tree binding but most + * bindings don't provide this information. Specifically, when the GPIO uclass + * calls the xlate() method, it can return default flags, which are then + * ORed with this @flags. + * + * If we find that requesting the GPIO is not always needed we could add a + * new function or a new GPIOD_NO_REQUEST flag. + * + * At present driver model has no reference counting so if one device + * requests a GPIO which subsequently is unbound, the @desc->dev pointer + * will be invalid. However this will only happen if the GPIO device is + * unbound, not if it is removed, so this seems like a reasonable limitation + * for now. There is no real use case for unbinding drivers in normal + * operation. + * + * The device tree binding is doc/device-tree-bindings/gpio/gpio.txt in + * generate terms and each specific device may add additional details in + * a binding file in the same directory. + * + * @dev: Device requesting the GPIO + * @list_name: Name of GPIO list (e.g. "board-id-gpios") + * @index: Index number of the GPIO in that list use request (0=first) + * @desc: Returns GPIO description information. If there is no such + * GPIO, dev->dev will be NULL. + * @flags: Indicates the GPIO input/output settings (GPIOD_...) + * @return 0 if OK, -ENOENT if the GPIO does not exist, -EINVAL if there is + * something wrong with the list, or other -ve for another error (e.g. + * -EBUSY if a GPIO was already requested) + */ +int gpio_request_by_name(struct udevice *dev, const char *list_name, + int index, struct gpio_desc *desc, int flags); + +/** + * gpio_request_list_by_name() - Request a list of GPIOs + * + * Reads all the GPIOs from a list and requetss them. See + * gpio_request_by_name() for additional details. Lists should not be + * misused to hold unrelated or optional GPIOs. They should only be used + * for things like parallel data lines. A zero phandle terminates the list + * the list. + * + * This function will either succeed, and request all GPIOs in the list, or + * fail and request none (it will free already-requested GPIOs in case of + * an error part-way through). + * + * @dev: Device requesting the GPIO + * @list_name: Name of GPIO list (e.g. "board-id-gpios") + * @desc_list: Returns a list of GPIO description information + * @max_count: Maximum number of GPIOs to return (@desc_list must be at least + * this big) + * @flags: Indicates the GPIO input/output settings (GPIOD_...) + * @return number of GPIOs requested, or -ve on error + */ +int gpio_request_list_by_name(struct udevice *dev, const char *list_name, + struct gpio_desc *desc_list, int max_count, + int flags); + +/** + * gpio_get_list_count() - Returns the number of GPIOs in a list + * + * Counts the GPIOs in a list. See gpio_request_by_name() for additional + * details. + * + * @dev: Device requesting the GPIO + * @list_name: Name of GPIO list (e.g. "board-id-gpios") + * @return number of GPIOs (0 for an empty property) or -ENOENT if the list + * does not exist + */ +int gpio_get_list_count(struct udevice *dev, const char *list_name); + +/** + * gpio_request_by_name_nodev() - request GPIOs without a device + * + * This is a version of gpio_request_list_by_name() that does not use a + * device. Avoid it unless the caller is not yet using driver model + */ +int gpio_request_by_name_nodev(const void *blob, int node, + const char *list_name, + int index, struct gpio_desc *desc, int flags); + +/** + * gpio_request_list_by_name_nodev() - request GPIOs without a device + * + * This is a version of gpio_request_list_by_name() that does not use a + * device. Avoid it unless the caller is not yet using driver model + */ +int gpio_request_list_by_name_nodev(const void *blob, int node, + const char *list_name, + struct gpio_desc *desc_list, int max_count, + int flags); + +/** + * dm_gpio_free() - Free a single GPIO + * + * This frees a single GPIOs previously returned from gpio_request_by_name(). + * + * @dev: Device which requested the GPIO + * @desc: GPIO to free + * @return 0 if OK, -ve on error + */ +int dm_gpio_free(struct udevice *dev, struct gpio_desc *desc); + +/** + * gpio_free_list() - Free a list of GPIOs + * + * This frees a list of GPIOs previously returned from + * gpio_request_list_by_name(). + * + * @dev: Device which requested the GPIOs + * @desc: List of GPIOs to free + * @count: Number of GPIOs in the list + * @return 0 if OK, -ve on error + */ +int gpio_free_list(struct udevice *dev, struct gpio_desc *desc, int count); + +/** + * gpio_free_list_nodev() - free GPIOs without a device + * + * This is a version of gpio_free_list() that does not use a + * device. Avoid it unless the caller is not yet using driver model + */ +int gpio_free_list_nodev(struct gpio_desc *desc, int count); + +/** + * dm_gpio_get_value() - Get the value of a GPIO + * + * This is the driver model version of the existing gpio_get_value() function + * and should be used instead of that. + * + * For now, these functions have a dm_ prefix since they conflict with + * existing names. + * + * @desc: GPIO description containing device, offset and flags, + * previously returned by gpio_request_by_name() + * @return GPIO value (0 for inactive, 1 for active) or -ve on error + */ +int dm_gpio_get_value(struct gpio_desc *desc); + +int dm_gpio_set_value(struct gpio_desc *desc, int value); + +/** + * dm_gpio_set_dir() - Set the direction for a GPIO + * + * This sets up the direction according tot the provided flags. It will do + * nothing unless the direction is actually specified. + * + * @desc: GPIO description containing device, offset and flags, + * previously returned by gpio_request_by_name() + * @return 0 if OK, -ve on error + */ +int dm_gpio_set_dir(struct gpio_desc *desc); + +/** + * dm_gpio_set_dir_flags() - Set direction using specific flags + * + * This is like dm_gpio_set_dir() except that the flags value is provided + * instead of being used from desc->flags. This is needed because in many + * cases the GPIO description does not include direction information. + * Note that desc->flags is updated by this function. + * + * @desc: GPIO description containing device, offset and flags, + * previously returned by gpio_request_by_name() + * @flags: New flags to use + * @return 0 if OK, -ve on error, in which case desc->flags is not updated + */ +int dm_gpio_set_dir_flags(struct gpio_desc *desc, ulong flags); + +/** + * gpio_get_number() - Get the global GPIO number of a GPIO + * + * This should only be used for debugging or interest. It returns the nummber + * that should be used for gpio_get_value() etc. to access this GPIO. + * + * @desc: GPIO description containing device, offset and flags, + * previously returned by gpio_request_by_name() + * @return GPIO number, or -ve if not found + */ +int gpio_get_number(struct gpio_desc *desc); + #endif /* _ASM_GENERIC_GPIO_H_ */ |
