hw/ssi: Add a "cs" property to SSIPeripheral

Boards will use this new property to identify the device CS line and
wire the SPI controllers accordingly.

Cc: Alistair Francis <alistair@alistair23.me>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

hw/ssi/ssi.c

@@ -13,6 +13,7 @@
  */
 
 #include "qemu/osdep.h"
+#include "hw/qdev-properties.h"
 #include "hw/ssi/ssi.h"
 #include "migration/vmstate.h"
 #include "qemu/module.h"
@@ -71,6 +72,11 @@ static void ssi_peripheral_realize(DeviceState *dev, Error **errp)
     ssc->realize(s, errp);
 }
 
+static Property ssi_peripheral_properties[] = {
+    DEFINE_PROP_UINT8("cs", SSIPeripheral, cs_index, 0),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
 static void ssi_peripheral_class_init(ObjectClass *klass, void *data)
 {
     SSIPeripheralClass *ssc = SSI_PERIPHERAL_CLASS(klass);
@@ -81,6 +87,7 @@ static void ssi_peripheral_class_init(ObjectClass *klass, void *data)
     if (!ssc->transfer_raw) {
         ssc->transfer_raw = ssi_transfer_raw_default;
     }
+    device_class_set_props(dc, ssi_peripheral_properties);
 }
 
 static const TypeInfo ssi_peripheral_info = {

include/hw/ssi/ssi.h

@@ -64,6 +64,9 @@ struct SSIPeripheral {
 
     /* Chip select state */
     bool cs;
+
+    /* Chip select index */
+    uint8_t cs_index;
 };
 
 extern const VMStateDescription vmstate_ssi_peripheral;