ARM: EXYNOS: Setup legacy i2c controller interrupts

On Exynos5 we have a new high-speed i2c controller. The interrupt
sources for the legacy and new controller are muxed and are controlled
via the SYSCON I2C_CFG register. At reset the interrupt source is
configured for the high-speed controller, to continue using the old
i2c controller we need to modify the I2C_CFG register.
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/mach-exynos/include/mach/regs-pmu.h

@@ -15,6 +15,7 @@
 #include <mach/map.h>
 
 #define S5P_PMUREG(x)				(S5P_VA_PMU + (x))
+#define S5P_SYSREG(x)				(S3C_VA_SYS + (x))
 
 #define S5P_CENTRAL_SEQ_CONFIGURATION		S5P_PMUREG(0x0200)
 
@@ -230,6 +231,7 @@
 
 /* For EXYNOS5 */
 
+#define EXYNOS5_SYS_I2C_CFG					S5P_SYSREG(0x0234)
 #define EXYNOS5_USB_CFG						S5P_PMUREG(0x0230)
 
 #define EXYNOS5_AUTO_WDTRESET_DISABLE				S5P_PMUREG(0x0408)

arch/arm/mach-exynos/mach-exynos5-dt.c

@@ -11,10 +11,12 @@
 
 #include <linux/of_platform.h>
 #include <linux/serial_core.h>
+#include <linux/io.h>
 
 #include <asm/mach/arch.h>
 #include <asm/hardware/gic.h>
 #include <mach/map.h>
+#include <mach/regs-pmu.h>
 
 #include <plat/cpu.h>
 #include <plat/regs-serial.h>
@@ -91,6 +93,28 @@ static void __init exynos5250_dt_map_io(void)
 
 static void __init exynos5250_dt_machine_init(void)
 {
+	struct device_node *i2c_np;
+	const char *i2c_compat = "samsung,s3c2440-i2c";
+	unsigned int tmp;
+
+	/*
+	 * Exynos5's legacy i2c controller and new high speed i2c
+	 * controller have muxed interrupt sources. By default the
+	 * interrupts for 4-channel HS-I2C controller are enabled.
+	 * If node for first four channels of legacy i2c controller
+	 * are available then re-configure the interrupts via the
+	 * system register.
+	 */
+	for_each_compatible_node(i2c_np, NULL, i2c_compat) {
+		if (of_device_is_available(i2c_np)) {
+			if (of_alias_get_id(i2c_np, "i2c") < 4) {
+				tmp = readl(EXYNOS5_SYS_I2C_CFG);
+				writel(tmp & ~(0x1 << of_alias_get_id(i2c_np, "i2c")),
+						EXYNOS5_SYS_I2C_CFG);
+			}
+		}
+	}
+
 	of_platform_populate(NULL, of_default_bus_match_table,
 				exynos5250_auxdata_lookup, NULL);
 }