From 'Application Note AN385', chapter 3.14:

  The SMM implements a simple SBCon interface based on I2C.

There are 4 SBCon interfaces on the FPGA APB subsystem.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/arm/mps2.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/hw/arm/mps2.c b/hw/arm/mps2.c
index daa26f68d7..2f6acbf2c2 100644
--- a/hw/arm/mps2.c
+++ b/hw/arm/mps2.c
@@ -40,6 +40,7 @@
 #include "hw/misc/mps2-scc.h"
 #include "hw/misc/mps2-fpgaio.h"
 #include "hw/ssi/pl022.h"
+#include "hw/i2c/arm_sbcon_i2c.h"
 #include "hw/net/lan9118.h"
 #include "net/net.h"
 #include "hw/watchdog/cmsdk-apb-watchdog.h"
@@ -365,6 +366,13 @@ static void mps2_common_init(MachineState *machine)
                                  qdev_get_gpio_in(orgate_dev, j));
         }
     }
+    for (i = 0; i < 4; i++) {
+        static const hwaddr i2cbase[] = {0x40022000,    /* Touch */
+                                         0x40023000,    /* Audio */
+                                         0x40029000,    /* Shield0 */
+                                         0x4002a000};   /* Shield1 */
+        sysbus_create_simple(TYPE_ARM_SBCON_I2C, i2cbase[i], NULL);
+    }
 
     /* In hardware this is a LAN9220; the LAN9118 is software compatible
      * except that it doesn't support the checksum-offload feature.
-- 
2.21.3