refactor(mode): validate mode property in Python class

Author: yochem

spidev/_cspi.c

@@ -1012,28 +1012,8 @@ SpiDev_set_mode(SpiDevObject *self, PyObject *val, void *closure)
 			"Cannot delete attribute");
 		return -1;
 	}
-#if PY_MAJOR_VERSION < 3
-	if (PyInt_Check(val)) {
-		mode = PyInt_AS_LONG(val);
-	} else
-#endif
-	{
-		if (PyLong_Check(val)) {
-			mode = PyLong_AS_LONG(val);
-		} else {
-			PyErr_SetString(PyExc_TypeError,
-				"The mode attribute must be an integer");
-			return -1;
-		}
-	}
-
 
-	if ( mode > 3 ) {
-		PyErr_SetString(PyExc_TypeError,
-			"The mode attribute must be an integer"
-				 "between 0 and 3.");
-		return -1;
-	}
+	mode = PyLong_AS_LONG(val);
 
 	// clean and set CPHA and CPOL bits
 	tmp = ( self->mode & ~(SPI_CPHA | SPI_CPOL) ) | mode ;

spidev/_spi.py

@@ -5,11 +5,40 @@
 
 
 class SpiDev(_cspi.SpiDev):
-    def __init__(self, bus: int | None, client: int | None, device: int | None = None):
+    def __init__(
+        self,
+        bus: int | None,
+        client: int | None,
+        device: int | None = None,
+        mode: int | None = None,
+    ):
+        super().__init__(bus, client)
         self.bus = bus
         self.client = client
         self.device = device
-        super().__init__(bus, client)
+        if mode is not None:
+            self.mode = mode
+
+    @property
+    def mode(self) -> int:
+        """SPI mode.
+
+        A two bit pattern of clock polarity and phase [CPOL|CPHA],
+        min: 0b00 = 0, max: 0b11 = 3
+        """
+        return super().mode
+
+    @mode.setter
+    def mode(self, value: int) -> None:
+        try:
+            v = int(value)
+        except (TypeError, ValueError):
+            raise TypeError(f"mode must be an integer, but is {value}")
+
+        if not 0 <= v <= 3:
+            raise ValueError(f"mode must be between 0 and 3, but is {v}")
+
+        super().__setattr__("mode", v)
 
     def fileno(self) -> int:
         """Return the file descriptor if it exists.