mirror of
https://github.com/u-boot/u-boot.git
synced 2024-12-05 18:43:27 +08:00
96495d90fe
Add driver model support for GPIOs. Since existing GPIO drivers do not use driver model, this feature must be enabled by CONFIG_DM_GPIO. After all GPO drivers are converted over we can perhaps remove this config. Tests are provided for the sandbox implementation, and are a sufficient sanity check for basic operation. The GPIO uclass understands the concept of named banks of GPIOs, with each GPIO device providing a single bank. Within each bank the GPIOs are numbered using an offset from 0 to n-1. For example a bank named 'b' with 20 offsets will provide GPIOs named b0 to b19. Anonymous GPIO banks are also supported, and are just numbered without any prefix. Each time a GPIO driver is added to the uclass, the GPIOs are renumbered accordinging, so there is always a global GPIO numbering order. Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Marek Vasut <marex@denx.de> Signed-off-by: Pavel Herrmann <morpheus.ibis@gmail.com> Signed-off-by: Viktor Křivák <viktor.krivak@gmail.com> Signed-off-by: Tomas Hlavacek <tmshlvck@gmail.com>
186 lines
5.9 KiB
C
186 lines
5.9 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
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
/**
|
|
* Request a gpio. This should be called before any of the other functions
|
|
* are used on this gpio.
|
|
*
|
|
* @param gp GPIO number
|
|
* @param label User label for this GPIO
|
|
* @return 0 if ok, -1 on error
|
|
*/
|
|
int gpio_request(unsigned gpio, const char *label);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* Make a GPIO an input.
|
|
*
|
|
* @param gpio GPIO number
|
|
* @return 0 if ok, -1 on error
|
|
*/
|
|
int gpio_direction_input(unsigned gpio);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
/**
|
|
* 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_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_ */
|