drm/stm: ltdc: add number of interrupts

The number of interrupts depends on the ltdc version.
Don't try to get interrupt which not exist, avoiding
kernel warning messages.
Signed-off-by: Yannick Fertre <yannick.fertre@st.com>
Acked-by: Philippe Cornu <philippe.cornu@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1579601632-7001-1-git-send-email-yannick.fertre@st.com

drivers/gpu/drm/stm/ltdc.c

@@ -1146,12 +1146,14 @@ static int ltdc_get_caps(struct drm_device *ddev)
 		ldev->caps.pad_max_freq_hz = 90000000;
 		if (ldev->caps.hw_version == HWVER_10200)
 			ldev->caps.pad_max_freq_hz = 65000000;
+		ldev->caps.nb_irq = 2;
 		break;
 	case HWVER_20101:
 		ldev->caps.reg_ofs = REG_OFS_4;
 		ldev->caps.pix_fmt_hw = ltdc_pix_fmt_a1;
 		ldev->caps.non_alpha_only_l1 = false;
 		ldev->caps.pad_max_freq_hz = 150000000;
+		ldev->caps.nb_irq = 4;
 		break;
 	default:
 		return -ENODEV;
@@ -1251,13 +1253,21 @@ int ltdc_load(struct drm_device *ddev)
 	reg_clear(ldev->regs, LTDC_IER,
 		  IER_LIE | IER_RRIE | IER_FUIE | IER_TERRIE);
 
-	for (i = 0; i < MAX_IRQ; i++) {
-		irq = platform_get_irq(pdev, i);
-		if (irq == -EPROBE_DEFER)
+	ret = ltdc_get_caps(ddev);
+	if (ret) {
+		DRM_ERROR("hardware identifier (0x%08x) not supported!\n",
+			  ldev->caps.hw_version);
 		goto err;
+	}
 
-		if (irq < 0)
-			continue;
+	DRM_DEBUG_DRIVER("ltdc hw version 0x%08x\n", ldev->caps.hw_version);
+
+	for (i = 0; i < ldev->caps.nb_irq; i++) {
+		irq = platform_get_irq(pdev, i);
+		if (irq < 0) {
+			ret = irq;
+			goto err;
+		}
 
 		ret = devm_request_threaded_irq(dev, irq, ltdc_irq,
 						ltdc_irq_thread, IRQF_ONESHOT,
@@ -1268,16 +1278,6 @@ int ltdc_load(struct drm_device *ddev)
 		}
 	}
 
-
-	ret = ltdc_get_caps(ddev);
-	if (ret) {
-		DRM_ERROR("hardware identifier (0x%08x) not supported!\n",
-			  ldev->caps.hw_version);
-		goto err;
-	}
-
-	DRM_DEBUG_DRIVER("ltdc hw version 0x%08x\n", ldev->caps.hw_version);
-
 	/* Add endpoints panels or bridges if any */
 	for (i = 0; i < MAX_ENDPOINTS; i++) {
 		if (panel[i]) {

drivers/gpu/drm/stm/ltdc.h

@@ -19,6 +19,7 @@ struct ltdc_caps {
 	const u32 *pix_fmt_hw;	/* supported pixel formats */
 	bool non_alpha_only_l1; /* non-native no-alpha formats on layer 1 */
 	int pad_max_freq_hz;	/* max frequency supported by pad */
+	int nb_irq;		/* number of hardware interrupts */
 };
 
 #define LTDC_MAX_LAYER	4