u-boot/arch/sandbox/include/asm/gpio.h
Simon Glass 8a45b22057 gpio: Add a way to read 3-way strapping pins
Using the internal vs. external pull resistors it is possible to get
27 different combinations from 3 strapping pins. Add an implementation
of this.

This involves updating the sandbox GPIO driver to model external and
(weaker) internal pull resistors. The get_value() method now takes account
of what is driving a pin:

   sandbox: GPIOD_EXT_DRIVEN - in which case GPIO_EXT_HIGH provides the
          value
   outside source - in which case GPIO_EXT_PULL_UP/DOWN indicates the
          external state and we work the final state using those flags and
          the internal GPIOD_PULL_UP/DOWN flags

Of course the outside source does not really exist in sandbox. We are just
modelling it for test purpose.

Signed-off-by: Simon Glass <sjg@chromium.org>
2021-03-03 15:40:47 -05:00

94 lines
3 KiB
C

/* SPDX-License-Identifier: GPL-2.0+ */
/*
* This is the interface to the sandbox GPIO driver for test code which
* wants to change the GPIO values reported to U-Boot.
*
* Copyright (c) 2011 The Chromium OS Authors.
*/
#ifndef __ASM_SANDBOX_GPIO_H
#define __ASM_SANDBOX_GPIO_H
/*
* We use the generic interface, and add a back-channel.
*
* The back-channel functions are declared in this file. They should not be used
* except in test code.
*
* Test code can, for example, call sandbox_gpio_set_value() to set the value of
* a simulated GPIO. From then on, normal code in U-Boot will see this new
* value when it calls gpio_get_value().
*
* NOTE: DO NOT use the functions in this file except in test code!
*/
#include <asm-generic/gpio.h>
/* Our own private GPIO flags, which musn't conflict with GPIOD_... */
#define GPIOD_EXT_HIGH BIT(31) /* external source is high (else low) */
#define GPIOD_EXT_DRIVEN BIT(30) /* external source is driven */
#define GPIOD_EXT_PULL_UP BIT(29) /* GPIO has external pull-up */
#define GPIOD_EXT_PULL_DOWN BIT(28) /* GPIO has external pull-down */
#define GPIOD_EXT_PULL (BIT(28) | BIT(29))
#define GPIOD_SANDBOX_MASK GENMASK(31, 28)
/**
* Return the simulated value of a GPIO (used only in sandbox test code)
*
* @param dev device to use
* @param offset GPIO offset within bank
* @return -1 on error, 0 if GPIO is low, >0 if high
*/
int sandbox_gpio_get_value(struct udevice *dev, unsigned int offset);
/**
* Set the simulated value of a GPIO (used only in sandbox test code)
*
* @param dev device to use
* @param offset GPIO offset within bank
* @param value value to set (0 for low, non-zero for high)
* @return -1 on error, 0 if ok
*/
int sandbox_gpio_set_value(struct udevice *dev, unsigned int offset, int value);
/**
* Return the simulated direction of a GPIO (used only in sandbox test code)
*
* @param dev device to use
* @param offset GPIO offset within bank
* @return -1 on error, 0 if GPIO is input, >0 if output
*/
int sandbox_gpio_get_direction(struct udevice *dev, unsigned int offset);
/**
* Set the simulated direction of a GPIO (used only in sandbox test code)
*
* @param dev device to use
* @param offset GPIO offset within bank
* @param output 0 to set as input, 1 to set as output
* @return -1 on error, 0 if ok
*/
int sandbox_gpio_set_direction(struct udevice *dev, unsigned int offset,
int output);
/**
* Return the simulated flags of a GPIO (used only in sandbox test code)
*
* @param dev device to use
* @param offset GPIO offset within bank
* @return dir_flags: bitfield accesses by GPIOD_ defines
*/
ulong sandbox_gpio_get_flags(struct udevice *dev, unsigned int offset);
/**
* Set the simulated flags of a GPIO (used only in sandbox test code)
*
* @param dev device to use
* @param offset GPIO offset within bank
* @param flags bitfield accesses by GPIOD_ defines
* @return -1 on error, 0 if ok
*/
int sandbox_gpio_set_flags(struct udevice *dev, unsigned int offset,
ulong flags);
#endif