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Commit 6831f3a9 authored by Kuninori Morimoto's avatar Kuninori Morimoto Committed by Paul Mundt
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ARM: mach-shmobile: r8a7740: add i2c support 



This patch adds I2C support to r8a7740 CPU
which has lasting errata on I2C I/O pad reset.
This patch is including work-around.

Signed-off-by: default avatarKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 5ade0672

arch/arm/mach-shmobile/setup-r8a7740.c

+106 −0
Original line number Diff line number Diff line
@@ -17,8 +17,10 @@ 
 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

#include <linux/delay.h>

#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/io.h>

#include <linux/platform_device.h>

#include <linux/serial_sci.h>

#include <linux/sh_timer.h>
@@ -233,10 +235,114 @@ static struct platform_device *r8a7740_early_devices[] __initdata = { 
	&cmt10_device,

};



/* I2C */

static struct resource i2c0_resources[] = {

	[0] = {

		.name	= "IIC0",

		.start	= 0xfff20000,

		.end	= 0xfff20425 - 1,

		.flags	= IORESOURCE_MEM,

	},

	[1] = {

		.start	= gic_spi(201),

		.end	= gic_spi(204),

		.flags	= IORESOURCE_IRQ,

	},

};



static struct resource i2c1_resources[] = {

	[0] = {

		.name	= "IIC1",

		.start	= 0xe6c20000,

		.end	= 0xe6c20425 - 1,

		.flags	= IORESOURCE_MEM,

	},

	[1] = {

		.start	= gic_spi(70),

		.end	= gic_spi(73),

		.flags	= IORESOURCE_IRQ,

	},

};



static struct platform_device i2c0_device = {

	.name		= "i2c-sh_mobile",

	.id		= 0,

	.resource	= i2c0_resources,

	.num_resources	= ARRAY_SIZE(i2c0_resources),

};



static struct platform_device i2c1_device = {

	.name		= "i2c-sh_mobile",

	.id		= 1,

	.resource	= i2c1_resources,

	.num_resources	= ARRAY_SIZE(i2c1_resources),

};



static struct platform_device *r8a7740_late_devices[] __initdata = {

	&i2c0_device,

	&i2c1_device,

};



#define ICCR	0x0004

#define ICSTART	0x0070



#define i2c_read(reg, offset)		ioread8(reg + offset)

#define i2c_write(reg, offset, data)	iowrite8(data, reg + offset)



/*

 * r8a7740 chip has lasting errata on I2C I/O pad reset.

 * this is work-around for it.

 */

static void r8a7740_i2c_workaround(struct platform_device *pdev)

{

	struct resource *res;

	void __iomem *reg;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (unlikely(!res)) {

		pr_err("r8a7740 i2c workaround fail (cannot find resource)\n");

		return;

	}



	reg = ioremap(res->start, resource_size(res));

	if (unlikely(!reg)) {

		pr_err("r8a7740 i2c workaround fail (cannot map IO)\n");

		return;

	}



	i2c_write(reg, ICCR, i2c_read(reg, ICCR) | 0x80);

	i2c_read(reg, ICCR); /* dummy read */



	i2c_write(reg, ICSTART, i2c_read(reg, ICSTART) | 0x10);

	i2c_read(reg, ICSTART); /* dummy read */



	mdelay(100);



	i2c_write(reg, ICCR, 0x01);

	i2c_read(reg, ICCR);

	i2c_write(reg, ICSTART, 0x00);

	i2c_read(reg, ICSTART);



	i2c_write(reg, ICCR, 0x10);

	mdelay(100);

	i2c_write(reg, ICCR, 0x00);

	mdelay(100);

	i2c_write(reg, ICCR, 0x10);

	mdelay(100);



	iounmap(reg);

}



void __init r8a7740_add_standard_devices(void)

{

	/* I2C work-around */

	r8a7740_i2c_workaround(&i2c0_device);

	r8a7740_i2c_workaround(&i2c1_device);



	platform_add_devices(r8a7740_early_devices,

			    ARRAY_SIZE(r8a7740_early_devices));

	platform_add_devices(r8a7740_late_devices,

			     ARRAY_SIZE(r8a7740_late_devices));

}



void __init r8a7740_add_early_devices(void)