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8a45b22057
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>
94 lines
3 KiB
C
94 lines
3 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* This is the interface to the sandbox GPIO driver for test code which
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* wants to change the GPIO values reported to U-Boot.
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*
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* Copyright (c) 2011 The Chromium OS Authors.
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*/
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#ifndef __ASM_SANDBOX_GPIO_H
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#define __ASM_SANDBOX_GPIO_H
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/*
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* We use the generic interface, and add a back-channel.
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*
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* The back-channel functions are declared in this file. They should not be used
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* except in test code.
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*
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* Test code can, for example, call sandbox_gpio_set_value() to set the value of
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* a simulated GPIO. From then on, normal code in U-Boot will see this new
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* value when it calls gpio_get_value().
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*
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* NOTE: DO NOT use the functions in this file except in test code!
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*/
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#include <asm-generic/gpio.h>
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/* Our own private GPIO flags, which musn't conflict with GPIOD_... */
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#define GPIOD_EXT_HIGH BIT(31) /* external source is high (else low) */
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#define GPIOD_EXT_DRIVEN BIT(30) /* external source is driven */
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#define GPIOD_EXT_PULL_UP BIT(29) /* GPIO has external pull-up */
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#define GPIOD_EXT_PULL_DOWN BIT(28) /* GPIO has external pull-down */
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#define GPIOD_EXT_PULL (BIT(28) | BIT(29))
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#define GPIOD_SANDBOX_MASK GENMASK(31, 28)
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/**
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* Return the simulated value of a GPIO (used only in sandbox test code)
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*
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* @param dev device to use
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* @param offset GPIO offset within bank
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* @return -1 on error, 0 if GPIO is low, >0 if high
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*/
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int sandbox_gpio_get_value(struct udevice *dev, unsigned int offset);
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/**
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* Set the simulated value of a GPIO (used only in sandbox test code)
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*
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* @param dev device to use
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* @param offset GPIO offset within bank
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* @param value value to set (0 for low, non-zero for high)
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* @return -1 on error, 0 if ok
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*/
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int sandbox_gpio_set_value(struct udevice *dev, unsigned int offset, int value);
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/**
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* Return the simulated direction of a GPIO (used only in sandbox test code)
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*
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* @param dev device to use
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* @param offset GPIO offset within bank
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* @return -1 on error, 0 if GPIO is input, >0 if output
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*/
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int sandbox_gpio_get_direction(struct udevice *dev, unsigned int offset);
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/**
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* Set the simulated direction of a GPIO (used only in sandbox test code)
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*
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* @param dev device to use
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* @param offset GPIO offset within bank
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* @param output 0 to set as input, 1 to set as output
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* @return -1 on error, 0 if ok
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*/
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int sandbox_gpio_set_direction(struct udevice *dev, unsigned int offset,
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int output);
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/**
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* Return the simulated flags of a GPIO (used only in sandbox test code)
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*
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* @param dev device to use
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* @param offset GPIO offset within bank
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* @return dir_flags: bitfield accesses by GPIOD_ defines
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*/
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ulong sandbox_gpio_get_flags(struct udevice *dev, unsigned int offset);
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/**
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* Set the simulated flags of a GPIO (used only in sandbox test code)
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*
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* @param dev device to use
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* @param offset GPIO offset within bank
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* @param flags bitfield accesses by GPIOD_ defines
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* @return -1 on error, 0 if ok
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*/
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int sandbox_gpio_set_flags(struct udevice *dev, unsigned int offset,
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ulong flags);
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#endif
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