[PATCH v3 2/4] hw/misc/pca9552: Add a PCA955X_LED_MAX definition

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

The current code models the PCA9552, but there are comments
saying the code could be easily adapted for the rest of the
PCA955x family.
Since we assume we have at most 16 LEDs (for the PCA9552),
add a definition and check the instance doesn't use more than
this number. This makes the code a bit safer in case other
PCA955x devices are added.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 hw/misc/pca9552.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/hw/misc/pca9552.c b/hw/misc/pca9552.c
index e015ef0e5d..00fa91b7f4 100644
--- a/hw/misc/pca9552.c
+++ b/hw/misc/pca9552.c
@@ -18,6 +18,8 @@
 #include "qapi/error.h"
 #include "qapi/visitor.h"
 
+#define PCA955X_LED_MAX 16
+
 #define PCA9552_LED_ON   0x0
 #define PCA9552_LED_OFF  0x1
 #define PCA9552_LED_PWM0 0x2
@@ -303,6 +305,17 @@ static void pca9552_initfn(Object *obj)
     }
 }
 
+static void pca9552_realize(DeviceState *dev, Error **errp)
+{
+    PCA9552State *s = PCA9552(dev);
+
+    if (s->nr_leds > PCA955X_LED_MAX) {
+        error_setg(errp, "%s invalid led count %u (max: %u)",
+                   __func__, s->nr_leds, PCA955X_LED_MAX);
+        return;
+    }
+}
+
 static void pca9552_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
@@ -311,6 +324,7 @@ static void pca9552_class_init(ObjectClass *klass, void *data)
     k->event = pca9552_event;
     k->recv = pca9552_recv;
     k->send = pca9552_send;
+    dc->realize = pca9552_realize;
     dc->reset = pca9552_reset;
     dc->vmsd = &pca9552_vmstate;
 }
-- 
2.21.3