hw/i2c/core: Add i2c_try_create_slave() and i2c_realize_and_unref()

Extract i2c_try_create_slave() and i2c_realize_and_unref()
from i2c_create_slave().
We can now set properties on a I2CSlave before it is realized.

This is in line with the recent qdev/QOM changes merged
in commit 6675a653d2e.

Reviewed-by: Corey Minyard <cminyard@mvista.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Tested-by: Cédric Le Goater <clg@kaod.org>
Message-id: 20200623072723.6324-2-f4bug@amsat.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 18 insertions, 2 deletions

diff --git a/hw/i2c/core.c b/hw/i2c/core.c
index 1aac457..acf34a1 100644
--- a/hw/i2c/core.c
+++ b/hw/i2c/core.c
@@ -267,13 +267,27 @@ const VMStateDescription vmstate_i2c_slave = {
     }
 };
 
-DeviceState *i2c_create_slave(I2CBus *bus, const char *name, uint8_t addr)
+DeviceState *i2c_try_create_slave(const char *name, uint8_t addr)
 {
     DeviceState *dev;
 
     dev = qdev_new(name);
     qdev_prop_set_uint8(dev, "address", addr);
-    qdev_realize_and_unref(dev, &bus->qbus, &error_fatal);
+    return dev;
+}
+
+bool i2c_realize_and_unref(DeviceState *dev, I2CBus *bus, Error **errp)
+{
+    return qdev_realize_and_unref(dev, &bus->qbus, errp);
+}
+
+DeviceState *i2c_create_slave(I2CBus *bus, const char *name, uint8_t addr)
+{
+    DeviceState *dev;
+
+    dev = i2c_try_create_slave(name, addr);
+    i2c_realize_and_unref(dev, bus, &error_fatal);
+
     return dev;
 }
 
diff --git a/include/hw/i2c/i2c.h b/include/hw/i2c/i2c.h
index 4117211..d6e3d85 100644
--- a/include/hw/i2c/i2c.h
+++ b/include/hw/i2c/i2c.h
@@ -80,6 +80,8 @@ int i2c_send(I2CBus *bus, uint8_t data);
 uint8_t i2c_recv(I2CBus *bus);
 
 DeviceState *i2c_create_slave(I2CBus *bus, const char *name, uint8_t addr);
+DeviceState *i2c_try_create_slave(const char *name, uint8_t addr);
+bool i2c_realize_and_unref(DeviceState *dev, I2CBus *bus, Error **errp);
 
 /* lm832x.c */
 void lm832x_key_event(DeviceState *dev, int key, int state);