Re: [PATCH 2/5] BCM2835: add gpio driver

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

On 23:52 Thu 11 Oct     , Carlo Caione wrote:
> Signed-off-by: Carlo Caione <carlo.caione@gmail.com>
> ---
>  drivers/gpio/Kconfig        |   4 ++
>  drivers/gpio/Makefile       |   1 +
>  drivers/gpio/gpio-bcm2835.c | 166 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 171 insertions(+)
>  create mode 100644 drivers/gpio/gpio-bcm2835.c
> 
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index a0e9b58..e8eeb6d 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -6,6 +6,10 @@ if GPIOLIB
>  
>  menu "GPIO                          "
>  
> +config GPIO_BCM2835
> +	bool "GPIO support for BCM2835"
> +	depends on ARCH_BCM2835
> +
>  config GPIO_PL061
>  	bool "PrimeCell PL061 GPIO support"
>  	depends on ARM_AMBA
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index e2e97d3..aecdf24 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -1,4 +1,5 @@
>  obj-$(CONFIG_GPIOLIB) += gpio.o
>  
> +obj-$(CONFIG_GPIO_BCM2835)	+= gpio-bcm2835.o
>  obj-$(CONFIG_GPIO_PL061)	+= gpio-pl061.o
>  obj-$(CONFIG_GPIO_STMPE) += gpio-stmpe.o
> diff --git a/drivers/gpio/gpio-bcm2835.c b/drivers/gpio/gpio-bcm2835.c
> new file mode 100644
> index 0000000..e31894c
> --- /dev/null
> +++ b/drivers/gpio/gpio-bcm2835.c
> @@ -0,0 +1,166 @@
> +/*
> + * Author: Carlo Caione <carlo@carlocaione.org>
> + *
> + * Based on linux/arch/arm/mach-bcm2708/bcm2708_gpio.c
> + *
> + * 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 <errno.h>
> +#include <malloc.h>
> +#include <io.h>
> +#include <gpio.h>
> +#include <init.h>
> +#include <mach/platform.h>
> +
> +#define GPIOFSEL(x)  (0x00+(x)*4)
> +#define GPIOSET(x)   (0x1c+(x)*4)
> +#define GPIOCLR(x)   (0x28+(x)*4)
> +#define GPIOLEV(x)   (0x34+(x)*4)
> +#define GPIOEDS(x)   (0x40+(x)*4)
> +#define GPIOREN(x)   (0x4c+(x)*4)
> +#define GPIOFEN(x)   (0x58+(x)*4)
> +#define GPIOHEN(x)   (0x64+(x)*4)
> +#define GPIOLEN(x)   (0x70+(x)*4)
> +#define GPIOAREN(x)  (0x7c+(x)*4)
> +#define GPIOAFEN(x)  (0x88+(x)*4)
> +#define GPIOUD(x)    (0x94+(x)*4)
> +#define GPIOUDCLK(x) (0x98+(x)*4)
> +
> +enum {
> +	GPIO_FSEL_INPUT, GPIO_FSEL_OUTPUT,
> +	GPIO_FSEL_ALT5, GPIO_FSEL_ALT_4,
> +	GPIO_FSEL_ALT0, GPIO_FSEL_ALT1,
> +	GPIO_FSEL_ALT2, GPIO_FSEL_ALT3,
> +};
> +
> +struct bcm2835_gpio_chip {
> +	void __iomem *base;
> +	struct gpio_chip chip;
> +};
> +
> +static int bcm2835_set_function(struct gpio_chip *chip, unsigned gpio, int function)
> +{
> +	struct bcm2835_gpio_chip *bcmgpio = container_of(chip, struct bcm2835_gpio_chip, chip);
> +	void __iomem *base = bcmgpio->base;
> +	unsigned gpiodir;
> +	unsigned gpio_bank = gpio / 10;
> +	unsigned gpio_field_offset = (gpio - 10 * gpio_bank) * 3;
> +
> +	gpiodir = readl(base + GPIOFSEL(gpio_bank));
> +	gpiodir &= ~(7 << gpio_field_offset);
> +	gpiodir |= function << gpio_field_offset;
> +	writel(gpiodir, base + GPIOFSEL(gpio_bank));
> +	gpiodir = readl(base + GPIOFSEL(gpio_bank));
> +
> +	return 0;
> +}
> +
> +static void bcm2835_gpio_set_value(struct gpio_chip *chip, unsigned gpio, int value)
> +{
> +	struct bcm2835_gpio_chip *bcmgpio = container_of(chip, struct bcm2835_gpio_chip, chip);
> +	void __iomem *base = bcmgpio->base;
> +	unsigned gpio_bank = gpio / 32;
> +	unsigned gpio_field_offset = gpio % 32;
> +
> +	if (value)
> +		writel(1 << gpio_field_offset, base + GPIOSET(gpio_bank));
> +	else
> +		writel(1 << gpio_field_offset, base + GPIOCLR(gpio_bank));
> +}
> +
> +static int bcm2835_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
> +{
> +	struct bcm2835_gpio_chip *bcmgpio = container_of(chip, struct bcm2835_gpio_chip, chip);
> +	void __iomem *base = bcmgpio->base;
> +	unsigned gpio_bank = gpio / 32;
> +	unsigned gpio_field_offset = gpio % 32;
> +	unsigned lev;
> +
> +	lev = readl(base + GPIOLEV(gpio_bank));
> +	return 0x1 & (lev >> gpio_field_offset);
> +}
> +
> +static int bcm2835_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
> +{
> +	return bcm2835_set_function(chip, gpio, GPIO_FSEL_INPUT);
> +}
> +
> +static int bcm2835_gpio_direction_output(struct gpio_chip *chip, unsigned gpio, int value)
> +{
> +	int ret;
missing empty line
> +	ret =  bcm2835_set_function(chip, gpio, GPIO_FSEL_OUTPUT);
always return 0
> +	if (ret >= 0)
> +		bcm2835_gpio_set_value(chip, gpio, value);
> +	return ret;
> +}
> +
Best Regards,
J.

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