OMAPDSS: remove compiler warnings when CONFIG_BUG=n

If CONFIG_BUG is not enabled, BUG() does not stop the execution. Many
places in code expect the execution to stop, and this causes compiler
warnings about uninitialized variables and returning from a non-void
function without a return value.

This patch fixes the warnings by initializing the variables and
returning properly after BUG() lines. However, the behaviour is still
undefined after the BUG, but this is the choice the user makes when
using CONFIG_BUG=n.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/omap2/dss/dispc.c

@@ -407,6 +407,7 @@ u32 dispc_mgr_get_vsync_irq(enum omap_channel channel)
 		return DISPC_IRQ_EVSYNC_ODD | DISPC_IRQ_EVSYNC_EVEN;
 	default:
 		BUG();
+		return 0;
 	}
 }
 
@@ -421,6 +422,7 @@ u32 dispc_mgr_get_framedone_irq(enum omap_channel channel)
 		return 0;
 	default:
 		BUG();
+		return 0;
 	}
 }
 
@@ -739,7 +741,7 @@ static void dispc_ovl_set_color_mode(enum omap_plane plane,
 		case OMAP_DSS_COLOR_XRGB16_1555:
 			m = 0xf; break;
 		default:
-			BUG(); break;
+			BUG(); return;
 		}
 	} else {
 		switch (color_mode) {
@@ -776,7 +778,7 @@ static void dispc_ovl_set_color_mode(enum omap_plane plane,
 		case OMAP_DSS_COLOR_XRGB16_1555:
 			m = 0xf; break;
 		default:
-			BUG(); break;
+			BUG(); return;
 		}
 	}
 
@@ -820,6 +822,7 @@ void dispc_ovl_set_channel_out(enum omap_plane plane, enum omap_channel channel)
 			break;
 		default:
 			BUG();
+			return;
 		}
 
 		val = FLD_MOD(val, chan, shift, shift);
@@ -847,6 +850,7 @@ static enum omap_channel dispc_ovl_get_channel_out(enum omap_plane plane)
 		break;
 	default:
 		BUG();
+		return 0;
 	}
 
 	val = dispc_read_reg(DISPC_OVL_ATTRIBUTES(plane));
@@ -1209,6 +1213,7 @@ static void dispc_ovl_set_accu_uv(enum omap_plane plane,
 		break;
 	default:
 		BUG();
+		return;
 	}
 
 	switch (color_mode) {
@@ -1224,6 +1229,7 @@ static void dispc_ovl_set_accu_uv(enum omap_plane plane,
 		break;
 	default:
 		BUG();
+		return;
 	}
 
 	accu_val = &accu_table[idx];
@@ -1339,6 +1345,7 @@ static void dispc_ovl_set_scaling_uv(enum omap_plane plane,
 		break;
 	default:
 		BUG();
+		return;
 	}
 
 	if (out_width != orig_width)
@@ -1466,6 +1473,7 @@ static int color_mode_to_bpp(enum omap_color_mode color_mode)
 		return 32;
 	default:
 		BUG();
+		return 0;
 	}
 }
 
@@ -1479,6 +1487,7 @@ static s32 pixinc(int pixels, u8 ps)
 		return 1 - (-pixels + 1) * ps;
 	else
 		BUG();
+		return 0;
 }
 
 static void calc_vrfb_rotation_offset(u8 rotation, bool mirror,
@@ -1562,6 +1571,7 @@ static void calc_vrfb_rotation_offset(u8 rotation, bool mirror,
 
 	default:
 		BUG();
+		return;
 	}
 }
 
@@ -1717,6 +1727,7 @@ static void calc_dma_rotation_offset(u8 rotation, bool mirror,
 
 	default:
 		BUG();
+		return;
 	}
 }
 
@@ -2106,6 +2117,11 @@ int dispc_ovl_setup(enum omap_plane plane, struct omap_overlay_info *oi,
 	if (fieldmode)
 		field_offset = 1;
 
+	offset0 = 0;
+	offset1 = 0;
+	row_inc = 0;
+	pix_inc = 0;
+
 	if (oi->rotation_type == OMAP_DSS_ROT_DMA)
 		calc_dma_rotation_offset(oi->rotation, oi->mirror,
 				oi->screen_width, in_width, frame_height,
@@ -2316,8 +2332,10 @@ bool dispc_mgr_is_enabled(enum omap_channel channel)
 		return !!REG_GET(DISPC_CONTROL, 1, 1);
 	else if (channel == OMAP_DSS_CHANNEL_LCD2)
 		return !!REG_GET(DISPC_CONTROL2, 0, 0);
-	else
+	else {
 		BUG();
+		return false;
+	}
 }
 
 void dispc_mgr_enable(enum omap_channel channel, bool enable)
@@ -2593,8 +2611,10 @@ void dispc_mgr_set_timings(enum omap_channel channel,
 	DSSDBG("channel %d xres %u yres %u\n", channel, timings->x_res,
 			timings->y_res);
 
-	if (!dispc_mgr_timings_ok(channel, timings))
+	if (!dispc_mgr_timings_ok(channel, timings)) {
 		BUG();
+		return;
+	}
 
 	if (dispc_mgr_is_lcd(channel)) {
 		_dispc_mgr_set_lcd_timings(channel, timings->hsw, timings->hfp,
@@ -2658,6 +2678,7 @@ unsigned long dispc_fclk_rate(void)
 		break;
 	default:
 		BUG();
+		return 0;
 	}
 
 	return r;
@@ -2688,6 +2709,7 @@ unsigned long dispc_mgr_lclk_rate(enum omap_channel channel)
 		break;
 	default:
 		BUG();
+		return 0;
 	}
 
 	return r / lcd;
@@ -2720,6 +2742,7 @@ unsigned long dispc_mgr_pclk_rate(enum omap_channel channel)
 			return hdmi_get_pixel_clock();
 		default:
 			BUG();
+			return 0;
 		}
 	}
 }