diff options
Diffstat (limited to 'drivers/gpio/bcm2835_gpio.c')
| -rw-r--r-- | drivers/gpio/bcm2835_gpio.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/drivers/gpio/bcm2835_gpio.c b/drivers/gpio/bcm2835_gpio.c new file mode 100644 index 0000000..1d50dbd --- /dev/null +++ b/drivers/gpio/bcm2835_gpio.c @@ -0,0 +1,89 @@ +/* + * 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(®->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, ®->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(®->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, ®->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(®->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; +} |