mirror of
https://github.com/u-boot/u-boot.git
synced 2024-12-06 02:53:37 +08:00
53ecdfb920
Certain GPIO devices have the capability to switch their GPIOs into open-drain mode, that is, instead of actively driving the output (Push-pull output), the 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. This patch adds functions to the GPIO uclass to switch GPIOs to open-drain mode on devices that support it. Signed-off-by: Mario Six <mario.six@gdsys.cc> Reviewed-by: Simon Glass <sjg@chromium.org> Reviewed-by: York Sun <york.sun@nxp.com>
626 lines
22 KiB
C
626 lines
22 KiB
C
/*
|
|
* Copyright (c) 2011 The Chromium OS Authors.
|
|
* Copyright (c) 2011, NVIDIA Corp. All rights reserved.
|
|
* SPDX-License-Identifier: GPL-2.0+
|
|
*/
|
|
|
|
#ifndef _ASM_GENERIC_GPIO_H_
|
|
#define _ASM_GENERIC_GPIO_H_
|
|
|
|
/*
|
|
* 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 fdtdec_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 fdtdec_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_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(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(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_ */
|