sandbox: gpio: add basic driver for simulating GPIOs
This provides a way of simulating GPIOs by setting values which are seen by the normal gpio_get/set_value() calls. Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
This commit is contained in:
Simon Glass
Mike Frysinger
parent
d9165153ca
commit
8d30fcd9a1
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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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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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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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/**
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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 gp GPIO number
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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(unsigned gp);
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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 gp GPIO number
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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(unsigned gp, 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 gp GPIO number
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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(unsigned gp);
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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 gp GPIO number
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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(unsigned gp, int output);
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/* Display information about each GPIO */
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void gpio_info(void);
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#define gpio_status() gpio_info()
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#endif
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@ -34,6 +34,7 @@ COBJS-$(CONFIG_MXS_GPIO) += mxs_gpio.o
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COBJS-$(CONFIG_PCA953X) += pca953x.o
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COBJS-$(CONFIG_PCA9698) += pca9698.o
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COBJS-$(CONFIG_S5P) += s5p_gpio.o
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COBJS-$(CONFIG_SANDBOX_GPIO) += sandbox.o
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COBJS-$(CONFIG_TEGRA2_GPIO) += tegra2_gpio.o
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COBJS-$(CONFIG_DA8XX_GPIO) += da8xx_gpio.o
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COBJS-$(CONFIG_ALTERA_PIO) += altera_pio.o
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@ -0,0 +1,209 @@
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/*
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* Copyright (c) 2011 The Chromium OS Authors.
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <common.h>
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#include <asm/gpio.h>
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/* Flags for each GPIO */
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#define GPIOF_OUTPUT (1 << 0) /* Currently set as an output */
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#define GPIOF_HIGH (1 << 1) /* Currently set high */
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#define GPIOF_RESERVED (1 << 2) /* Is in use / requested */
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struct gpio_state {
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const char *label; /* label given by requester */
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u8 flags; /* flags (GPIOF_...) */
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};
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/*
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* State of GPIOs
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* TODO: Put this into sandbox state
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*/
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static struct gpio_state state[CONFIG_SANDBOX_GPIO_COUNT];
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/* Access routines for GPIO state */
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static u8 *get_gpio_flags(unsigned gp)
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{
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/* assert()'s could be disabled, so make sure we handle that */
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assert(gp < ARRAY_SIZE(state));
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if (gp >= ARRAY_SIZE(state)) {
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static u8 invalid_flags;
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printf("sandbox_gpio: error: invalid gpio %u\n", gp);
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return &invalid_flags;
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}
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return &state[gp].flags;
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}
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static int get_gpio_flag(unsigned gp, int flag)
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{
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return (*get_gpio_flags(gp) & flag) != 0;
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}
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static int set_gpio_flag(unsigned gp, int flag, int value)
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{
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u8 *gpio = get_gpio_flags(gp);
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if (value)
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*gpio |= flag;
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else
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*gpio &= ~flag;
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return 0;
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}
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static int check_reserved(unsigned gpio, const char *func)
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{
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if (!get_gpio_flag(gpio, GPIOF_RESERVED)) {
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printf("sandbox_gpio: %s: error: gpio %u not reserved\n",
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func, gpio);
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return -1;
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}
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return 0;
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}
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/*
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* Back-channel sandbox-internal-only access to GPIO state
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*/
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int sandbox_gpio_get_value(unsigned gp)
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{
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if (get_gpio_flag(gp, GPIOF_OUTPUT))
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debug("sandbox_gpio: get_value on output gpio %u\n", gp);
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return get_gpio_flag(gp, GPIOF_HIGH);
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}
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int sandbox_gpio_set_value(unsigned gp, int value)
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{
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return set_gpio_flag(gp, GPIOF_HIGH, value);
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}
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int sandbox_gpio_get_direction(unsigned gp)
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{
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return get_gpio_flag(gp, GPIOF_OUTPUT);
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}
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int sandbox_gpio_set_direction(unsigned gp, int output)
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{
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return set_gpio_flag(gp, GPIOF_OUTPUT, output);
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}
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/*
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* These functions implement the public interface within U-Boot
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*/
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/* set GPIO port 'gp' as an input */
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int gpio_direction_input(unsigned gp)
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{
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debug("%s: gp:%u\n", __func__, gp);
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if (check_reserved(gp, __func__))
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return -1;
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return sandbox_gpio_set_direction(gp, 0);
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}
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/* set GPIO port 'gp' as an output, with polarity 'value' */
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int gpio_direction_output(unsigned gp, int value)
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{
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debug("%s: gp:%u, value = %d\n", __func__, gp, value);
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if (check_reserved(gp, __func__))
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return -1;
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return sandbox_gpio_set_direction(gp, 1) |
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sandbox_gpio_set_value(gp, value);
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}
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/* read GPIO IN value of port 'gp' */
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int gpio_get_value(unsigned gp)
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{
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debug("%s: gp:%u\n", __func__, gp);
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if (check_reserved(gp, __func__))
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return -1;
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return sandbox_gpio_get_value(gp);
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}
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/* write GPIO OUT value to port 'gp' */
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int gpio_set_value(unsigned gp, int value)
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{
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debug("%s: gp:%u, value = %d\n", __func__, gp, value);
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if (check_reserved(gp, __func__))
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return -1;
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if (!sandbox_gpio_get_direction(gp)) {
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printf("sandbox_gpio: error: set_value on input gpio %u\n", gp);
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return -1;
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}
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return sandbox_gpio_set_value(gp, value);
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}
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int gpio_request(unsigned gp, const char *label)
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{
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debug("%s: gp:%u, label:%s\n", __func__, gp, label);
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if (gp >= ARRAY_SIZE(state)) {
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printf("sandbox_gpio: error: invalid gpio %u\n", gp);
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return -1;
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}
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if (get_gpio_flag(gp, GPIOF_RESERVED)) {
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printf("sandbox_gpio: error: gpio %u already reserved\n", gp);
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return -1;
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}
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state[gp].label = label;
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return set_gpio_flag(gp, GPIOF_RESERVED, 1);
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}
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int gpio_free(unsigned gp)
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{
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debug("%s: gp:%u\n", __func__, gp);
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if (check_reserved(gp, __func__))
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return -1;
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state[gp].label = NULL;
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return set_gpio_flag(gp, GPIOF_RESERVED, 0);
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}
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/* Display GPIO information */
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void gpio_info(void)
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{
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unsigned gpio;
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puts("Sandbox GPIOs\n");
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for (gpio = 0; gpio < ARRAY_SIZE(state); ++gpio) {
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const char *label = state[gpio].label;
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printf("%4d: %s: %d [%c] %s\n",
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gpio,
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sandbox_gpio_get_direction(gpio) ? "out" : " in",
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sandbox_gpio_get_value(gpio),
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get_gpio_flag(gpio, GPIOF_RESERVED) ? 'x' : ' ',
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label ? label : "");
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}
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}
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