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Diffstat (limited to 'include/asm-generic/gpio.h')
| -rw-r--r-- | include/asm-generic/gpio.h | 660 |
1 files changed, 660 insertions, 0 deletions
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h new file mode 100644 index 0000000..d6cf187 --- /dev/null +++ b/include/asm-generic/gpio.h @@ -0,0 +1,660 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Copyright (c) 2011 The Chromium OS Authors. + * Copyright (c) 2011, NVIDIA Corp. All rights reserved. + */ + +#ifndef _ASM_GENERIC_GPIO_H_ +#define _ASM_GENERIC_GPIO_H_ + +#include <dm/ofnode.h> + +struct ofnode_phandle_args; + +/* + * 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. + * + * Each GPIO can be an input or output. If an input then its value can + * be read as 0 or 1. If an output then its value can be set to 0 or 1. + * If you try to write an input then the value is undefined. If you try + * to read an output, barring something very unusual, you will get + * back the value of the output that you previously set. + * + * In some cases the operation may fail, for example if the GPIO number + * is out of range, or the GPIO is not available because its pin is + * being used by another function. In that case, functions may return + * an error value of -1. + */ + +/** + * @deprecated Please use driver model instead + * Request a GPIO. This should be called before any of the other functions + * are used on this GPIO. + * + * Note: With driver model, the label is allocated so there is no need for + * the caller to preserve it. + * + * @param gpio GPIO number + * @param label User label for this GPIO + * @return 0 if ok, -1 on error + */ +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 + * @return 0 if ok, -1 on error + */ +int gpio_free(unsigned gpio); + +/** + * @deprecated Please use driver model instead + * Make a GPIO an input. + * + * @param gpio GPIO number + * @return 0 if ok, -1 on error + */ +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 + * @param value GPIO value (0 for low or 1 for high) + * @return 0 if ok, -1 on error + */ +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. + * + * @param gpio GPIO number + * @return 0 if low, 1 if high, -1 on error + */ +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. + * + * @param gpio GPIO number + * @param value GPIO value (0 for low or 1 for high) + * @return 0 if ok, -1 on error + */ +int gpio_set_value(unsigned gpio, int value); + +/* State of a GPIO, as reported by get_function() */ +enum gpio_func_t { + GPIOF_INPUT = 0, + GPIOF_OUTPUT, + GPIOF_UNUSED, /* Not claimed */ + GPIOF_UNKNOWN, /* Not known */ + GPIOF_FUNC, /* Not used as a GPIO */ + + GPIOF_COUNT, +}; + +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 input */ +#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 valid + * + * @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(const struct gpio_desc *desc) +{ + return desc->dev != NULL; +} + +/** + * gpio_get_status() - get the current GPIO status as a string + * + * Obtain the current GPIO status as a string which can be presented to the + * user. A typical string is: + * + * "b4: in: 1 [x] sdmmc_cd" + * + * 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 + * @buffsize: Size of string including \0 + */ +int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize); + +/** + * gpio_get_function() - get the current function for a GPIO pin + * + * 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 name given when the GPIO + * was requested, or -1 if it has not been requested + * @return -ENODATA if the driver returned an unknown function, + * -ENODEV if the device is not active, -EINVAL if the offset is invalid. + * GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the + * function from enum gpio_func_t. + */ +int gpio_get_function(struct udevice *dev, int offset, const char **namep); + +/** + * gpio_get_raw_function() - get the current raw function for a GPIO pin + * + * 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 name given when the GPIO + * was requested, or -1 if it has not been requested + * @return -ENODATA if the driver returned an unknown function, + * -ENODEV if the device is not active, -EINVAL if the offset is invalid. + * Otherwise returns the function from enum gpio_func_t. + */ +int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep); + +/** + * gpio_requestf() - request a GPIO using a format string for the owner + * + * This is a helper function for gpio_request(). It allows you to provide + * a printf()-format string for the GPIO owner. It calls gpio_request() with + * the string that is created + */ +int gpio_requestf(unsigned gpio, const char *fmt, ...) + __attribute__ ((format (__printf__, 2, 3))); + +struct fdtdec_phandle_args; + +/** + * gpio_xlate_offs_flags() - implementation for common use of dm_gpio_ops.xlate + * + * This routine sets the offset field to args[0] and the flags field to + * GPIOD_ACTIVE_LOW if the GPIO_ACTIVE_LOW flag is present in args[1]. + */ +int gpio_xlate_offs_flags(struct udevice *dev, struct gpio_desc *desc, + struct ofnode_phandle_args *args); + +/** + * 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. + * + * Also 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 together 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 udevice *dev, unsigned offset, const char *label); + int (*free)(struct udevice *dev, unsigned offset); + int (*direction_input)(struct udevice *dev, unsigned offset); + int (*direction_output)(struct udevice *dev, unsigned offset, + int value); + int (*get_value)(struct udevice *dev, unsigned offset); + int (*set_value)(struct udevice *dev, unsigned offset, int value); + int (*get_open_drain)(struct udevice *dev, unsigned offset); + int (*set_open_drain)(struct udevice *dev, unsigned offset, int value); + /** + * get_function() Get the GPIO function + * + * @dev: Device to check + * @offset: GPIO offset within that device + * @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 0 + * + * This method is optional and defaults to gpio_xlate_offs_flags, + * which will parse offset and the GPIO_ACTIVE_LOW flag in the first + * two arguments. + * + * 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 description + * @return 0 if OK, -ve on error + */ + int (*xlate)(struct udevice *dev, struct gpio_desc *desc, + struct ofnode_phandle_args *args); +}; + +/** + * 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 about 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. + * @name: Array of pointers to the name for each GPIO in this bank. The + * value of the pointer will be NULL if the GPIO has not been claimed. + */ +struct gpio_dev_priv { + const char *bank_name; + unsigned gpio_count; + unsigned gpio_base; + char **name; +}; + +/* 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 udevice *dev, int *offset_count); + +/** + * dm_gpio_lookup_name() - Look up a named GPIO and return its description + * + * The name of a GPIO is typically its bank name followed by a number from 0. + * For example A0 is the first GPIO in bank A. Each bank is a separate driver + * model device. + * + * @name: Name to look up + * @desc: Returns description, on success + * @return 0 if OK, -ve on error + */ +int dm_gpio_lookup_name(const char *name, struct gpio_desc *desc); + +/** + * gpio_hog_lookup_name() - Look up a named GPIO and return the gpio descr. + * + * @name: Name to look up + * @desc: Returns GPIO description, on success, else NULL + * @return: Returns 0 if OK, else -ENODEV + */ +int gpio_hog_lookup_name(const char *name, struct gpio_desc **desc); + +/** + * gpio_hog_probe_all() - probe all gpio devices with + * gpio-hog subnodes. + * + * @return: Returns return value from device_probe() + */ +int gpio_hog_probe_all(void); + +/** + * 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 udevice **devp, + unsigned int *offsetp, unsigned int *gpiop); + +/** + * gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int + * + * This puts the value of the first GPIO into bit 0, the second into bit 1, + * etc. then returns the resulting integer. + * + * @gpio_list: List of GPIOs to collect + * @return resulting integer value, or -ve on error + */ +int gpio_get_values_as_int(const int *gpio_list); + +/** + * dm_gpio_get_values_as_int() - Turn the values of a list of GPIOs into an int + * + * This puts the value of the first GPIO into bit 0, the second into bit 1, + * etc. then returns the resulting integer. + * + * @desc_list: List of GPIOs to collect + * @count: Number of GPIOs + * @return resulting integer value, or -ve on error + */ +int dm_gpio_get_values_as_int(const struct gpio_desc *desc_list, int count); + +/** + * gpio_claim_vector() - claim a number of GPIOs for input + * + * @gpio_num_array: array of gpios to claim, terminated by -1 + * @fmt: format string for GPIO names, e.g. "board_id%d" + * @return 0 if OK, -ve on error + */ +int gpio_claim_vector(const int *gpio_num_array, const char *fmt); + +/** + * 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 requests 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); + +/** + * dm_gpio_request() - manually request a GPIO + * + * Note: This function should only be used for testing / debugging. Instead. + * use gpio_request_by_name() to pull GPIOs from the device tree. + * + * @desc: GPIO description of GPIO to request (see dm_gpio_lookup_name()) + * @label: Label to attach to the GPIO while claimed + * @return 0 if OK, -ve on error + */ +int dm_gpio_request(struct gpio_desc *desc, const char *label); + +/** + * 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(ofnode 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(ofnode node, const char *list_name, + struct gpio_desc *desc_list, int max_count, + int flags); + +/** + * gpio_dev_request_index() - request single GPIO from gpio device + * + * @dev: GPIO device + * @nodename: Name of node for which gpio gets requested, used + * for the gpio label name + * @list_name: Name of GPIO list (e.g. "board-id-gpios") + * @index: Index number of the GPIO in that list use request (0=first) + * @flags: GPIOD_* flags + * @dtflags: GPIO flags read from DT defined see GPIOD_* + * @desc: returns GPIO descriptor filled from this function + * @return: return value from gpio_request_tail() + */ +int gpio_dev_request_index(struct udevice *dev, const char *nodename, + char *list_name, int index, int flags, + int dtflags, struct gpio_desc *desc); + +/** + * 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(const struct gpio_desc *desc); + +int dm_gpio_set_value(const struct gpio_desc *desc, int value); + +/** + * dm_gpio_get_open_drain() - Check if open-drain-mode of a GPIO is active + * + * This checks if open-drain-mode for a GPIO is enabled or not. This method is + * optional. + * + * @desc: GPIO description containing device, offset and flags, + * previously returned by gpio_request_by_name() + * @return Value of open drain mode for GPIO (0 for inactive, 1 for active) or + * -ve on error + */ +int dm_gpio_get_open_drain(struct gpio_desc *desc); + +/** + * dm_gpio_set_open_drain() - Switch open-drain-mode of a GPIO on or off + * + * This enables or disables open-drain mode for a GPIO. This method is + * optional; if the driver does not support it, nothing happens when the method + * is called. + * + * In open-drain mode, instead of actively driving the output (Push-pull + * output), the GPIO's pin is connected to the collector (for a NPN transistor) + * or the drain (for a MOSFET) of a transistor, respectively. The pin then + * either forms an open circuit or a connection to ground, depending on the + * state of the transistor. + * + * @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_open_drain(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 number + * 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(const struct gpio_desc *desc); + +#endif /* _ASM_GENERIC_GPIO_H_ */ |