u-boot/drivers/gpio/bcm2835_gpio.c
Stephen Warren efad6cf881 ARM: add basic support for the Broadcom BCM2835 SoC
This SoC is used in the Raspberry Pi, for example.

For more details, see:
http://www.broadcom.com/products/BCM2835
http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf.

Initial support is enough to boot to a serial console, execute a minimal
set of U-Boot commands, download data over a serial port, and boot a
Linux kernel. No storage or network drivers are implemented.

GPIO driver originally by Vikram Narayanan <vikram186@gmail.com>
with many fixes from myself.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
2012-09-01 14:58:21 +02:00

89 lines
2.3 KiB
C

/*
* Copyright (C) 2012 Vikram Narayananan
* <vikram186@gmail.com>
*
* 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.
*/
#include <common.h>
#include <asm/gpio.h>
#include <asm/io.h>
inline int gpio_is_valid(unsigned gpio)
{
return (gpio < BCM2835_GPIO_COUNT);
}
int gpio_request(unsigned gpio, const char *label)
{
return !gpio_is_valid(gpio);
}
int gpio_free(unsigned gpio)
{
return 0;
}
int gpio_direction_input(unsigned gpio)
{
struct bcm2835_gpio_regs *reg =
(struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE;
unsigned val;
val = readl(&reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
val &= ~(BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio));
val |= (BCM2835_GPIO_INPUT << BCM2835_GPIO_FSEL_SHIFT(gpio));
writel(val, &reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
return 0;
}
int gpio_direction_output(unsigned gpio, int value)
{
struct bcm2835_gpio_regs *reg =
(struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE;
unsigned val;
gpio_set_value(gpio, value);
val = readl(&reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
val &= ~(BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio));
val |= (BCM2835_GPIO_OUTPUT << BCM2835_GPIO_FSEL_SHIFT(gpio));
writel(val, &reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
return 0;
}
int gpio_get_value(unsigned gpio)
{
struct bcm2835_gpio_regs *reg =
(struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE;
unsigned val;
val = readl(&reg->gplev[BCM2835_GPIO_COMMON_BANK(gpio)]);
return (val >> BCM2835_GPIO_COMMON_SHIFT(gpio)) & 0x1;
}
int gpio_set_value(unsigned gpio, int value)
{
struct bcm2835_gpio_regs *reg =
(struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE;
u32 *output_reg = value ? reg->gpset : reg->gpclr;
writel(1 << BCM2835_GPIO_COMMON_SHIFT(gpio),
&output_reg[BCM2835_GPIO_COMMON_BANK(gpio)]);
return 0;
}