e1000e: fix LED blink logic for designs with LEDs driven by cathode

When the LEDs are driven by cathode, the bit logic is reversed.  Use the
LED Invert bit to invert the logic.  Cleanup use of a magic number and
change the for loop increment to reduce the number of shifts.
Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/e1000e/mac.c

@@ -1600,15 +1600,28 @@ s32 e1000e_blink_led_generic(struct e1000_hw *hw)
 		ledctl_blink = E1000_LEDCTL_LED0_BLINK |
 		    (E1000_LEDCTL_MODE_LED_ON << E1000_LEDCTL_LED0_MODE_SHIFT);
 	} else {
-		/* set the blink bit for each LED that's "on" (0x0E)
-		 * in ledctl_mode2
+		/* Set the blink bit for each LED that's "on" (0x0E)
+		 * (or "off" if inverted) in ledctl_mode2.  The blink
+		 * logic in hardware only works when mode is set to "on"
+		 * so it must be changed accordingly when the mode is
+		 * "off" and inverted.
 		 */
 		ledctl_blink = hw->mac.ledctl_mode2;
-		for (i = 0; i < 4; i++)
-			if (((hw->mac.ledctl_mode2 >> (i * 8)) & 0xFF) ==
-			    E1000_LEDCTL_MODE_LED_ON)
-				ledctl_blink |= (E1000_LEDCTL_LED0_BLINK <<
-						 (i * 8));
+		for (i = 0; i < 32; i += 8) {
+			u32 mode = (hw->mac.ledctl_mode2 >> i) &
+			    E1000_LEDCTL_LED0_MODE_MASK;
+			u32 led_default = hw->mac.ledctl_default >> i;
+
+			if ((!(led_default & E1000_LEDCTL_LED0_IVRT) &&
+			     (mode == E1000_LEDCTL_MODE_LED_ON)) ||
+			    ((led_default & E1000_LEDCTL_LED0_IVRT) &&
+			     (mode == E1000_LEDCTL_MODE_LED_OFF))) {
+				ledctl_blink &=
+				    ~(E1000_LEDCTL_LED0_MODE_MASK << i);
+				ledctl_blink |= (E1000_LEDCTL_LED0_BLINK |
+						 E1000_LEDCTL_MODE_LED_ON) << i;
+			}
+		}
 	}
 
 	ew32(LEDCTL, ledctl_blink);