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https://github.com/smaeul/u-boot.git
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e5901c94e3
For board IDs a common approach is to set aside several GPIOs for use in determining the board ID. This can provide information about board features and the revision. Add a function that turns a list of GPIOs into an integer by assigning each GPIO to a single bit. Signed-off-by: Simon Glass <sjg@chromium.org>
272 lines
8.9 KiB
C
272 lines
8.9 KiB
C
/*
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* Copyright (c) 2011 The Chromium OS Authors.
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* Copyright (c) 2011, NVIDIA Corp. All rights reserved.
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#ifndef _ASM_GENERIC_GPIO_H_
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#define _ASM_GENERIC_GPIO_H_
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/*
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* Generic GPIO API for U-Boot
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*
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* GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined
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* by the SOC/architecture.
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*
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* Each GPIO can be an input or output. If an input then its value can
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* be read as 0 or 1. If an output then its value can be set to 0 or 1.
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* If you try to write an input then the value is undefined. If you try
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* to read an output, barring something very unusual, you will get
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* back the value of the output that you previously set.
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*
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* In some cases the operation may fail, for example if the GPIO number
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* is out of range, or the GPIO is not available because its pin is
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* being used by another function. In that case, functions may return
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* an error value of -1.
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*/
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/**
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* Request a GPIO. This should be called before any of the other functions
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* are used on this GPIO.
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*
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* Note: With driver model, the label is allocated so there is no need for
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* the caller to preserve it.
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*
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* @param gp GPIO number
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* @param label User label for this GPIO
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* @return 0 if ok, -1 on error
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*/
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int gpio_request(unsigned gpio, const char *label);
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/**
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* Stop using the GPIO. This function should not alter pin configuration.
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*
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* @param gpio GPIO number
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* @return 0 if ok, -1 on error
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*/
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int gpio_free(unsigned gpio);
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/**
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* Make a GPIO an input.
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*
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* @param gpio GPIO number
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* @return 0 if ok, -1 on error
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*/
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int gpio_direction_input(unsigned gpio);
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/**
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* Make a GPIO an output, and set its value.
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*
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* @param gpio GPIO number
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* @param value GPIO value (0 for low or 1 for high)
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* @return 0 if ok, -1 on error
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*/
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int gpio_direction_output(unsigned gpio, int value);
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/**
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* Get a GPIO's value. This will work whether the GPIO is an input
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* or an output.
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*
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* @param gpio GPIO number
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* @return 0 if low, 1 if high, -1 on error
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*/
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int gpio_get_value(unsigned gpio);
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/**
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* Set an output GPIO's value. The GPIO must already be an output or
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* this function may have no effect.
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*
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* @param gpio GPIO number
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* @param value GPIO value (0 for low or 1 for high)
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* @return 0 if ok, -1 on error
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*/
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int gpio_set_value(unsigned gpio, int value);
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/* State of a GPIO, as reported by get_function() */
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enum gpio_func_t {
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GPIOF_INPUT = 0,
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GPIOF_OUTPUT,
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GPIOF_UNUSED, /* Not claimed */
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GPIOF_UNKNOWN, /* Not known */
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GPIOF_FUNC, /* Not used as a GPIO */
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GPIOF_COUNT,
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};
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struct udevice;
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/**
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* gpio_get_status() - get the current GPIO status as a string
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*
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* Obtain the current GPIO status as a string which can be presented to the
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* user. A typical string is:
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*
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* "b4: in: 1 [x] sdmmc_cd"
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*
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* which means this is GPIO bank b, offset 4, currently set to input, current
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* value 1, [x] means that it is requested and the owner is 'sdmmc_cd'
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*
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* @dev: Device to check
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* @offset: Offset of device GPIO to check
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* @buf: Place to put string
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* @buffsize: Size of string including \0
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*/
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int gpio_get_status(struct udevice *dev, int offset, char *buf, int buffsize);
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/**
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* gpio_get_function() - get the current function for a GPIO pin
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*
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* Note this returns GPIOF_UNUSED if the GPIO is not requested.
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*
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* @dev: Device to check
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* @offset: Offset of device GPIO to check
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* @namep: If non-NULL, this is set to the nane given when the GPIO
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* was requested, or -1 if it has not been requested
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* @return -ENODATA if the driver returned an unknown function,
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* -ENODEV if the device is not active, -EINVAL if the offset is invalid.
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* GPIOF_UNUSED if the GPIO has not been requested. Otherwise returns the
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* function from enum gpio_func_t.
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*/
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int gpio_get_function(struct udevice *dev, int offset, const char **namep);
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/**
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* gpio_get_raw_function() - get the current raw function for a GPIO pin
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*
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* Note this does not return GPIOF_UNUSED - it will always return the GPIO
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* driver's view of a pin function, even if it is not correctly set up.
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*
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* @dev: Device to check
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* @offset: Offset of device GPIO to check
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* @namep: If non-NULL, this is set to the nane given when the GPIO
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* was requested, or -1 if it has not been requested
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* @return -ENODATA if the driver returned an unknown function,
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* -ENODEV if the device is not active, -EINVAL if the offset is invalid.
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* Otherwise returns the function from enum gpio_func_t.
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*/
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int gpio_get_raw_function(struct udevice *dev, int offset, const char **namep);
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/**
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* gpio_requestf() - request a GPIO using a format string for the owner
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*
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* This is a helper function for gpio_request(). It allows you to provide
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* a printf()-format string for the GPIO owner. It calls gpio_request() with
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* the string that is created
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*/
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int gpio_requestf(unsigned gpio, const char *fmt, ...)
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__attribute__ ((format (__printf__, 2, 3)));
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/**
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* struct struct dm_gpio_ops - Driver model GPIO operations
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*
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* Refer to functions above for description. These function largely copy
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* the old API.
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*
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* This is trying to be close to Linux GPIO API. Once the U-Boot uses the
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* new DM GPIO API, this should be really easy to flip over to the Linux
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* GPIO API-alike interface.
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*
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* Also it would be useful to standardise additional functions like
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* pullup, slew rate and drive strength.
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*
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* gpio_request)( and gpio_free() are optional - if NULL then they will
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* not be called.
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*
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* Note that @offset is the offset from the base GPIO of the device. So
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* offset 0 is the device's first GPIO and offset o-1 is the last GPIO,
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* where o is the number of GPIO lines controlled by the device. A device
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* is typically used to control a single bank of GPIOs. Within complex
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* SoCs there may be many banks and therefore many devices all referring
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* to the different IO addresses within the SoC.
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*
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* The uclass combines all GPIO devices together to provide a consistent
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* numbering from 0 to n-1, where n is the number of GPIOs in total across
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* all devices. Be careful not to confuse offset with gpio in the parameters.
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*/
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struct dm_gpio_ops {
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int (*request)(struct udevice *dev, unsigned offset, const char *label);
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int (*free)(struct udevice *dev, unsigned offset);
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int (*direction_input)(struct udevice *dev, unsigned offset);
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int (*direction_output)(struct udevice *dev, unsigned offset,
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int value);
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int (*get_value)(struct udevice *dev, unsigned offset);
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int (*set_value)(struct udevice *dev, unsigned offset, int value);
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/**
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* get_function() Get the GPIO function
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*
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* @dev: Device to check
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* @offset: GPIO offset within that device
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* @return current function - GPIOF_...
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*/
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int (*get_function)(struct udevice *dev, unsigned offset);
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};
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/**
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* struct gpio_dev_priv - information about a device used by the uclass
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*
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* The uclass combines all active GPIO devices into a unified numbering
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* scheme. To do this it maintains some private information about each
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* device.
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*
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* To implement driver model support in your GPIO driver, add a probe
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* handler, and set @gpio_count and @bank_name correctly in that handler.
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* This tells the uclass the name of the GPIO bank and the number of GPIOs
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* it contains.
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*
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* @bank_name: Name of the GPIO device (e.g 'a' means GPIOs will be called
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* 'A0', 'A1', etc.
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* @gpio_count: Number of GPIOs in this device
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* @gpio_base: Base GPIO number for this device. For the first active device
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* this will be 0; the numbering for others will follow sequentially so that
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* @gpio_base for device 1 will equal the number of GPIOs in device 0.
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* @name: Array of pointers to the name for each GPIO in this bank. The
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* value of the pointer will be NULL if the GPIO has not been claimed.
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*/
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struct gpio_dev_priv {
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const char *bank_name;
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unsigned gpio_count;
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unsigned gpio_base;
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char **name;
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};
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/* Access the GPIO operations for a device */
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#define gpio_get_ops(dev) ((struct dm_gpio_ops *)(dev)->driver->ops)
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/**
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* gpio_get_bank_info - Return information about a GPIO bank/device
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*
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* This looks up a device and returns both its GPIO base name and the number
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* of GPIOs it controls.
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*
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* @dev: Device to look up
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* @offset_count: Returns number of GPIOs within this bank
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* @return bank name of this device
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*/
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const char *gpio_get_bank_info(struct udevice *dev, int *offset_count);
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/**
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* gpio_lookup_name - Look up a GPIO name and return its details
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*
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* This is used to convert a named GPIO into a device, offset and GPIO
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* number.
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*
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* @name: GPIO name to look up
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* @devp: Returns pointer to device which contains this GPIO
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* @offsetp: Returns the offset number within this device
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* @gpiop: Returns the absolute GPIO number, numbered from 0
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*/
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int gpio_lookup_name(const char *name, struct udevice **devp,
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unsigned int *offsetp, unsigned int *gpiop);
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/**
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* get_gpios() - Turn the values of a list of GPIOs into an integer
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*
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* This puts the value of the first GPIO into bit 0, the second into bit 1,
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* etc. then returns the resulting integer.
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*
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* @gpio_list: List of GPIOs to collect
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* @return resulting integer value
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*/
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unsigned gpio_get_values_as_int(const int *gpio_list);
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#endif /* _ASM_GENERIC_GPIO_H_ */
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