drm/exynos/decon5433: refactor irq requesting code

To allow runtime validation of mode of work irq request
code should be split into two separate phases:
- irq reqesting,
- irq checking.
Following patches will move 2nd phase to mode validation phase.
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos5433_drm_decon.c

@@ -58,6 +58,8 @@ struct decon_context {
 	struct regmap			*sysreg;
 	struct clk			*clks[ARRAY_SIZE(decon_clks_name)];
 	unsigned int			irq;
+	unsigned int			irq_vsync;
+	unsigned int			irq_lcd_sys;
 	unsigned int			te_irq;
 	unsigned long			out_type;
 	int				first_win;
@@ -670,20 +672,23 @@ static const struct of_device_id exynos5433_decon_driver_dt_match[] = {
 MODULE_DEVICE_TABLE(of, exynos5433_decon_driver_dt_match);
 
 static int decon_conf_irq(struct decon_context *ctx, const char *name,
-		irq_handler_t handler, unsigned long int flags, bool required)
+		irq_handler_t handler, unsigned long int flags)
 {
 	struct platform_device *pdev = to_platform_device(ctx->dev);
 	int ret, irq = platform_get_irq_byname(pdev, name);
 
 	if (irq < 0) {
-		if (irq == -EPROBE_DEFER)
+		switch (irq) {
+		case -EPROBE_DEFER:
 			return irq;
-		if (required)
-			dev_err(ctx->dev, "cannot get %s IRQ\n", name);
-		else
-			irq = 0;
+		case -ENODATA:
+		case -ENXIO:
+			return 0;
+		default:
+			dev_err(ctx->dev, "IRQ %s get failed, %d\n", name, irq);
 			return irq;
 		}
+	}
 	irq_set_status_flags(irq, IRQ_NOAUTOEN);
 	ret = devm_request_irq(ctx->dev, irq, handler, flags, "drm_decon", ctx);
 	if (ret < 0) {
@@ -738,26 +743,27 @@ static int exynos5433_decon_probe(struct platform_device *pdev)
 		return PTR_ERR(ctx->addr);
 	}
 
-	if (ctx->out_type & IFTYPE_I80) {
-		ret = decon_conf_irq(ctx, "lcd_sys", decon_irq_handler, 0, true);
+	ret = decon_conf_irq(ctx, "vsync", decon_irq_handler, 0);
 	if (ret < 0)
 		return ret;
-		ctx->irq = ret;
+	ctx->irq_vsync = ret;
+
+	ret = decon_conf_irq(ctx, "lcd_sys", decon_irq_handler, 0);
+	if (ret < 0)
+		return ret;
+	ctx->irq_lcd_sys = ret;
+
+	ctx->irq = (ctx->out_type & IFTYPE_I80) ? ctx->irq_lcd_sys
+						: ctx->irq_vsync;
 
 	ret = decon_conf_irq(ctx, "te", decon_te_irq_handler,
-				     IRQF_TRIGGER_RISING, false);
+			IRQF_TRIGGER_RISING);
 	if (ret < 0)
 			return ret;
 	if (ret) {
 		ctx->te_irq = ret;
 		ctx->out_type &= ~I80_HW_TRG;
 	}
-	} else {
-		ret = decon_conf_irq(ctx, "vsync", decon_irq_handler, 0, true);
-		if (ret < 0)
-			return ret;
-		ctx->irq = ret;
-	}
 
 	if (ctx->out_type & I80_HW_TRG) {
 		ctx->sysreg = syscon_regmap_lookup_by_phandle(dev->of_node,