[U-Boot] [PATCH v5] sandbox: gpio: Add basic driver for simulating GPIOs
Simon Glass
sjg at chromium.org
Wed Feb 22 06:45:52 CET 2012
On Tue, Feb 21, 2012 at 9:08 PM, Mike Frysinger <vapier at gentoo.org> wrote:
> let's get your ack-back on this and i'll merge it into my branch.
> only diff from last code is restored assert() to get_gpio_flags().
> -mike
>
> From f67fd9b82ec180d8a227bf036a45eb31e713a5a9 Mon Sep 17 00:00:00 2001
> From: Simon Glass <sjg at chromium.org>
> Date: Wed, 15 Feb 2012 15:51:13 -0800
> Subject: [PATCH v5] 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 at chromium.org>
> Signed-off-by: Mike Frysinger <vapier at gentoo.org>
Acked-by: Simon Glass <sjg at chromium.org>
> ---
> v5
> - combine simon & my work
>
> arch/sandbox/include/asm/gpio.h | 81 +++++++++++++++
> drivers/gpio/Makefile | 1 +
> drivers/gpio/sandbox.c | 209 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 291 insertions(+), 0 deletions(-)
> create mode 100644 arch/sandbox/include/asm/gpio.h
> create mode 100644 drivers/gpio/sandbox.c
>
> diff --git a/arch/sandbox/include/asm/gpio.h b/arch/sandbox/include/asm/gpio.h
> new file mode 100644
> index 0000000..0500c53
> --- /dev/null
> +++ b/arch/sandbox/include/asm/gpio.h
> @@ -0,0 +1,81 @@
> +/*
> + * 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.
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
> + * MA 02111-1307 USA
> + */
> +
> +#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>
> +
> +/**
> + * Return the simulated value of a GPIO (used only in sandbox test code)
> + *
> + * @param gp GPIO number
> + * @return -1 on error, 0 if GPIO is low, >0 if high
> + */
> +int sandbox_gpio_get_value(unsigned gp);
> +
> +/**
> + * Set the simulated value of a GPIO (used only in sandbox test code)
> + *
> + * @param gp GPIO number
> + * @param value value to set (0 for low, non-zero for high)
> + * @return -1 on error, 0 if ok
> + */
> +int sandbox_gpio_set_value(unsigned gp, int value);
> +
> +/**
> + * Return the simulated direction of a GPIO (used only in sandbox test code)
> + *
> + * @param gp GPIO number
> + * @return -1 on error, 0 if GPIO is input, >0 if output
> + */
> +int sandbox_gpio_get_direction(unsigned gp);
> +
> +/**
> + * Set the simulated direction of a GPIO (used only in sandbox test code)
> + *
> + * @param gp GPIO number
> + * @param output 0 to set as input, 1 to set as output
> + * @return -1 on error, 0 if ok
> + */
> +int sandbox_gpio_set_direction(unsigned gp, int output);
> +
> +/* Display information about each GPIO */
> +void gpio_info(void);
> +
> +#define gpio_status() gpio_info()
> +
> +#endif
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index 4375a55..fb3b09a 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -34,6 +34,7 @@ COBJS-$(CONFIG_MXS_GPIO) += mxs_gpio.o
> COBJS-$(CONFIG_PCA953X) += pca953x.o
> COBJS-$(CONFIG_PCA9698) += pca9698.o
> COBJS-$(CONFIG_S5P) += s5p_gpio.o
> +COBJS-$(CONFIG_SANDBOX_GPIO) += sandbox.o
> COBJS-$(CONFIG_TEGRA2_GPIO) += tegra2_gpio.o
> COBJS-$(CONFIG_DA8XX_GPIO) += da8xx_gpio.o
> COBJS-$(CONFIG_ALTERA_PIO) += altera_pio.o
> diff --git a/drivers/gpio/sandbox.c b/drivers/gpio/sandbox.c
> new file mode 100644
> index 0000000..19d2db0
> --- /dev/null
> +++ b/drivers/gpio/sandbox.c
> @@ -0,0 +1,209 @@
> +/*
> + * Copyright (c) 2011 The Chromium OS Authors.
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
> + * MA 02111-1307 USA
> + */
> +
> +#include <common.h>
> +#include <asm/gpio.h>
> +
> +/* Flags for each GPIO */
> +#define GPIOF_OUTPUT (1 << 0) /* Currently set as an output */
> +#define GPIOF_HIGH (1 << 1) /* Currently set high */
> +#define GPIOF_RESERVED (1 << 2) /* Is in use / requested */
> +
> +struct gpio_state {
> + const char *label; /* label given by requester */
> + u8 flags; /* flags (GPIOF_...) */
> +};
> +
> +/*
> + * State of GPIOs
> + * TODO: Put this into sandbox state
> + */
> +static struct gpio_state state[CONFIG_SANDBOX_GPIO_COUNT];
> +
> +/* Access routines for GPIO state */
> +static u8 *get_gpio_flags(unsigned gp)
> +{
> + /* assert()'s could be disabled, so make sure we handle that */
> + assert(gp < ARRAY_SIZE(state));
> + if (gp >= ARRAY_SIZE(state)) {
> + static u8 invalid_flags;
> + printf("sandbox_gpio: error: invalid gpio %u\n", gp);
> + return &invalid_flags;
> + }
> +
> + return &state[gp].flags;
> +}
> +
> +static int get_gpio_flag(unsigned gp, int flag)
> +{
> + return (*get_gpio_flags(gp) & flag) != 0;
> +}
> +
> +static int set_gpio_flag(unsigned gp, int flag, int value)
> +{
> + u8 *gpio = get_gpio_flags(gp);
> +
> + if (value)
> + *gpio |= flag;
> + else
> + *gpio &= ~flag;
> +
> + return 0;
> +}
> +
> +static int check_reserved(unsigned gpio, const char *func)
> +{
> + if (!get_gpio_flag(gpio, GPIOF_RESERVED)) {
> + printf("sandbox_gpio: %s: error: gpio %u not reserved\n",
> + func, gpio);
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * Back-channel sandbox-internal-only access to GPIO state
> + */
> +
> +int sandbox_gpio_get_value(unsigned gp)
> +{
> + if (get_gpio_flag(gp, GPIOF_OUTPUT))
> + debug("sandbox_gpio: get_value on output gpio %u\n", gp);
> + return get_gpio_flag(gp, GPIOF_HIGH);
> +}
> +
> +int sandbox_gpio_set_value(unsigned gp, int value)
> +{
> + return set_gpio_flag(gp, GPIOF_HIGH, value);
> +}
> +
> +int sandbox_gpio_get_direction(unsigned gp)
> +{
> + return get_gpio_flag(gp, GPIOF_OUTPUT);
> +}
> +
> +int sandbox_gpio_set_direction(unsigned gp, int output)
> +{
> + return set_gpio_flag(gp, GPIOF_OUTPUT, output);
> +}
> +
> +/*
> + * These functions implement the public interface within U-Boot
> + */
> +
> +/* set GPIO port 'gp' as an input */
> +int gpio_direction_input(unsigned gp)
> +{
> + debug("%s: gp:%u\n", __func__, gp);
> +
> + if (check_reserved(gp, __func__))
> + return -1;
> +
> + return sandbox_gpio_set_direction(gp, 0);
> +}
> +
> +/* set GPIO port 'gp' as an output, with polarity 'value' */
> +int gpio_direction_output(unsigned gp, int value)
> +{
> + debug("%s: gp:%u, value = %d\n", __func__, gp, value);
> +
> + if (check_reserved(gp, __func__))
> + return -1;
> +
> + return sandbox_gpio_set_direction(gp, 1) |
> + sandbox_gpio_set_value(gp, value);
> +}
> +
> +/* read GPIO IN value of port 'gp' */
> +int gpio_get_value(unsigned gp)
> +{
> + debug("%s: gp:%u\n", __func__, gp);
> +
> + if (check_reserved(gp, __func__))
> + return -1;
> +
> + return sandbox_gpio_get_value(gp);
> +}
> +
> +/* write GPIO OUT value to port 'gp' */
> +int gpio_set_value(unsigned gp, int value)
> +{
> + debug("%s: gp:%u, value = %d\n", __func__, gp, value);
> +
> + if (check_reserved(gp, __func__))
> + return -1;
> +
> + if (!sandbox_gpio_get_direction(gp)) {
> + printf("sandbox_gpio: error: set_value on input gpio %u\n", gp);
> + return -1;
> + }
> +
> + return sandbox_gpio_set_value(gp, value);
> +}
> +
> +int gpio_request(unsigned gp, const char *label)
> +{
> + debug("%s: gp:%u, label:%s\n", __func__, gp, label);
> +
> + if (gp >= ARRAY_SIZE(state)) {
> + printf("sandbox_gpio: error: invalid gpio %u\n", gp);
> + return -1;
> + }
> +
> + if (get_gpio_flag(gp, GPIOF_RESERVED)) {
> + printf("sandbox_gpio: error: gpio %u already reserved\n", gp);
> + return -1;
> + }
> +
> + state[gp].label = label;
> + return set_gpio_flag(gp, GPIOF_RESERVED, 1);
> +}
> +
> +int gpio_free(unsigned gp)
> +{
> + debug("%s: gp:%u\n", __func__, gp);
> +
> + if (check_reserved(gp, __func__))
> + return -1;
> +
> + state[gp].label = NULL;
> + return set_gpio_flag(gp, GPIOF_RESERVED, 0);
> +}
> +
> +/* Display GPIO information */
> +void gpio_info(void)
> +{
> + unsigned gpio;
> +
> + puts("Sandbox GPIOs\n");
> +
> + for (gpio = 0; gpio < ARRAY_SIZE(state); ++gpio) {
> + const char *label = state[gpio].label;
> +
> + printf("%4d: %s: %d [%c] %s\n",
> + gpio,
> + sandbox_gpio_get_direction(gpio) ? "out" : " in",
> + sandbox_gpio_get_value(gpio),
> + get_gpio_flag(gpio, GPIOF_RESERVED) ? 'x' : ' ',
> + label ? label : "");
> + }
> +}
> --
> 1.7.8.4
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