Driver for BCM2835 SoC. This gives the basic functionality of setting/clearing the output.
Signed-off-by: Vikram Narayanan vikram186@gmail.com --- arch/arm/include/asm/arch-bcm2835/gpio.h | 71 ++++++++++++++++++++++++ drivers/gpio/Makefile | 1 + drivers/gpio/bcm2835_gpio.c | 88 ++++++++++++++++++++++++++++++ 3 files changed, 160 insertions(+), 0 deletions(-) create mode 100644 arch/arm/include/asm/arch-bcm2835/gpio.h create mode 100644 drivers/gpio/bcm2835_gpio.c
diff --git a/arch/arm/include/asm/arch-bcm2835/gpio.h b/arch/arm/include/asm/arch-bcm2835/gpio.h new file mode 100644 index 0000000..515456a --- /dev/null +++ b/arch/arm/include/asm/arch-bcm2835/gpio.h @@ -0,0 +1,71 @@ +/* + * 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. + * + * 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 _BCM2835_GPIO_H_ +#define _BCM2835_GPIO_H_ + +#define BCM2835_GPIO_BASE 0x7E200000 +#define BCM2835_GPIO_COUNT 53 + +#define BCM2835_GPIO_FSEL_MASK 0x7 +#define BCM2835_GPIO_INPUT 0x0 +#define BCM2835_GPIO_OUTPUT 0x1 +#define BCM2835_GPIO_ALT0 0x2 +#define BCM2835_GPIO_ALT1 0x3 +#define BCM2835_GPIO_ALT2 0x4 +#define BCM2835_GPIO_ALT3 0x5 +#define BCM2835_GPIO_ALT4 0x6 +#define BCM2835_GPIO_ALT5 0x7 + +#define BCM2835_GPIO_COMMON_BANK(gpio) ((gpio < 32) ? 0 : 1) +#define BCM2835_GPIO_COMMON_SHIFT(gpio) (gpio & 0x1f) + +#define BCM2835_GPIO_FSEL_BANK(gpio) (gpio / 10) +#define BCM2835_GPIO_FSEL_SHIFT(gpio) ((gpio % 10) * 3) + +struct bcm_gpio_regs { + u32 gpfsel[6]; + u32 reserved1; + u32 gpset[2]; + u32 reserved2; + u32 gpclr[2]; + u32 reserved3; + u32 gplev[2]; + u32 reserved4; + u32 gpeds[2]; + u32 reserved5; + u32 gpren[2]; + u32 reserved6; + u32 gpfen[2]; + u32 reserved7; + u32 gphen[2]; + u32 reserved8; + u32 gplen[2]; + u32 reserved9; + u32 gparen[2]; + u32 reserved10; + u32 gppud; + u32 gppudclk[2]; +}; + +#endif /* _BCM2835_GPIO_H_ */ diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index 32a2474..8d2f2b2 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -40,6 +40,7 @@ COBJS-$(CONFIG_TEGRA_GPIO) += tegra_gpio.o COBJS-$(CONFIG_DA8XX_GPIO) += da8xx_gpio.o COBJS-$(CONFIG_ALTERA_PIO) += altera_pio.o COBJS-$(CONFIG_MPC83XX_GPIO) += mpc83xx_gpio.o +COBJS-$(CONFIG_BCM2835_GPIO) += bcm2835_gpio.o
COBJS := $(COBJS-y) SRCS := $(COBJS:.o=.c) diff --git a/drivers/gpio/bcm2835_gpio.c b/drivers/gpio/bcm2835_gpio.c new file mode 100644 index 0000000..eb02efa --- /dev/null +++ b/drivers/gpio/bcm2835_gpio.c @@ -0,0 +1,88 @@ +/* + * 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. + * + * 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> +#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 bcm_gpio_regs *reg = (struct bcm_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, reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]); + } + +int gpio_direction_output(unsigned gpio, int value) +{ + struct bcm_gpio_regs *reg = (struct bcm_gpio_regs *)BCM2835_GPIO_BASE; + unsigned val; + + if (value) + 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, reg->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]); +} + +int gpio_get_value(unsigned gpio) +{ + struct bcm_gpio_regs *reg = (struct bcm_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 bcm_gpio_regs *reg = (struct bcm_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; +} +