hw/i3c/aspeed: Add I3C bus get function

To retrieve the I3C bus object normally, the order is Aspeed I3C -> DW
I3C[n] -> bus object, so make a nice wrapper for people to use.

Signed-off-by: Joe Komlodi <komlodi@google.com>
Reviewed-by: Jamin Lin <jamin_lin@aspeedtech.com>
Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
Tested-by: Jithu Joseph <jithu.joseph@oss.qualcomm.com>
Link: https://lore.kernel.org/qemu-devel/20260225021158.1586584-18-jamin_lin@aspeedtech.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

hw/i3c/aspeed_i3c.c

@@ -153,6 +153,15 @@ static const MemoryRegionOps aspeed_i3c_ops = {
     }
 };
 
+I3CBus *aspeed_i3c_get_bus(AspeedI3CState *s, uint8_t bus_num)
+{
+    if (bus_num < ARRAY_SIZE(s->devices)) {
+        return s->devices[bus_num].bus;
+    }
+    /* Developer error, fail fast. */
+    g_assert_not_reached();
+}
+
 static void aspeed_i3c_reset(DeviceState *dev)
 {
     AspeedI3CState *s = ASPEED_I3C(dev);

include/hw/i3c/aspeed_i3c.h

@@ -31,4 +31,7 @@ struct AspeedI3CState {
     DWI3C devices[ASPEED_I3C_NR_DEVICES];
     uint8_t id;
 };
+
+I3CBus *aspeed_i3c_get_bus(AspeedI3CState *s, uint8_t bus_num);
+
 #endif /* ASPEED_I3C_H */