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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: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Kuninori Morimoto 2011-11-10 18:46:23 -08:00 committed by Paul Mundt
parent 5ade0672f2
commit 6831f3a918
1 changed files with 106 additions and 0 deletions
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106
arch/arm/mach-shmobile/setup-r8a7740.c
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@ -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)