Re: [PATCH] Add GPIO support and GPIO setup features to the S3C processors

[Sascha Hauer <s.hauer@pengutronix.de>]

On Mon, Oct 18, 2010 at 06:43:39PM +0200, Juergen Beisert wrote:
> From: Juergen Beisert <juergen@kreuzholzen.de>
> Subject: Add GPIO support and GPIO setup features to the S3C processors
> 
> This patch adds genetic GPIO support to all S3C2440 processor based systems.
> Also it adds definitions to setup the pin multiplexer in a way the other
> architectures do.
> 
> Note: Tested on a S3C2440 based system only. But should work on an S3C2410, too.
> 
> Signed-off-by: Juergen Beisert <juergen@kreuzholzen.de>
> 
> ---
>  arch/arm/Kconfig                                   |    1 
>  arch/arm/mach-s3c24xx/Makefile                     |    2 
>  arch/arm/mach-s3c24xx/gpio-s3c24x0.c               |  170 ++++++++
>  arch/arm/mach-s3c24xx/include/mach/gpio.h          |   31 +
>  arch/arm/mach-s3c24xx/include/mach/iomux-s3c24x0.h |  426 +++++++++++++++++++++
>  5 files changed, 629 insertions(+), 1 deletion(-)
> 
> Index: barebox-2010.10.0/arch/arm/mach-s3c24xx/gpio-s3c24x0.c
> ===================================================================
> --- /dev/null
> +++ barebox-2010.10.0/arch/arm/mach-s3c24xx/gpio-s3c24x0.c
> @@ -0,0 +1,170 @@
> +/*
> + * 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 <asm/io.h>
> +#include <mach/s3c24x0-iomap.h>
> +#include <mach/gpio.h>
> +
> +static const unsigned char group_offset[] =
> +{
> +	0x00,	/* GPA */
> +	0x10,	/* GPB */
> +	0x20,	/* GPC */
> +	0x30,	/* GPD */
> +	0x40,	/* GPE */
> +	0x50,	/* GPF */
> +	0x60,	/* GPG */
> +	0x70,	/* GPH */
> +#ifdef CONFIG_CPU_S3C2440
> +	0xd0,	/* GPJ */
> +#endif
> +};
> +
> +void gpio_set_value(unsigned gpio, int value)
> +{
> +	unsigned group = gpio >> 5;
> +	unsigned bit = gpio % 32;
> +	unsigned offset;
> +	uint32_t reg;
> +
> +	offset = group_offset[group];
> +
> +	reg = readl(GPADAT + offset);
> +	reg &= ~(1 << bit);
> +	reg |= (!!value) << bit;
> +	writel(reg, GPADAT + offset);
> +}
> +
> +int gpio_direction_input(unsigned gpio)
> +{
> +	unsigned group = gpio >> 5;
> +	unsigned bit = gpio % 32;
> +	unsigned offset;
> +	uint32_t reg;
> +
> +	offset = group_offset[group];
> +
> +	reg = readl(GPACON + offset);
> +	reg &= ~(0x3 << (bit << 1));
> +	writel(reg, GPACON + offset);
> +
> +	return 0;
> +}
> +
> +
> +int gpio_direction_output(unsigned gpio, int value)
> +{
> +	unsigned group = gpio >> 5;
> +	unsigned bit = gpio % 32;
> +	unsigned offset;
> +	uint32_t reg;
> +
> +	offset = group_offset[group];
> +
> +	/* value */
> +	reg = readl(GPADAT + offset);
> +	reg &= ~(1 << bit);
> +	reg |= (!!value) << bit;
> +	writel(reg, GPADAT + offset);

You can call gpio_set_value here.

> +
> +	/* direction */
> +	if (group == 0) {	/* GPA is special */
> +		reg = readl(GPACON);
> +		reg &= ~(1 << bit);
> +		writel(reg, GPACON);
> +	} else {

gpio_direction_input does not have this special handling. Is this
correct?

> +		reg = readl(GPACON + offset);
> +		reg &= ~(0x3 << (bit << 1));
> +		reg |= 0x1 << (bit << 1);
> +		writel(reg, GPACON + offset);
> +	}
> +
> +	return 0;
> +}
> +
-- 
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