[U-Boot] [PATCH v3 1/2] gpio: bcm2835: Add GPIO driver

Vikram Narayanan vikram186 at gmail.com
Wed Aug 1 04:31:14 CEST 2012 

On 7/31/2012 11:18 PM, Vikram Narayanan wrote:
> Driver for BCM2835 SoC. This gives the basic functionality of
> setting/clearing the output.
>
> Signed-off-by: Vikram Narayanan<vikram186 at 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 at 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

GPIO count should be 54 to make the gpio_is_valid work correctly when 
the gpio is 53.
Will fix in v4.

Any other comments?

> +
> +#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 at 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(&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)]);
> +	}
> +
> +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(&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)]);
> +}
> +
> +int gpio_get_value(unsigned gpio)
> +{
> +	struct bcm_gpio_regs *reg = (struct bcm_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 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;
> +}
> +

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