i2c: amd-mp2: use msix/msi if the hardware supports

Use msix or msi interrupts if the hardware supports it. Else, fallback to
legacy interrupts.

Co-developed-by: Basavaraj Natikar <[e-mail]>
Signed-off-by: Basavaraj Natikar <[e-mail]>
Signed-off-by: Raju Rangoju <[e-mail]>
Acked-by: Shyam Sundar S K <[e-mail]>
Signed-off-by: Wolfram Sang <[e-mail]>

drivers/i2c/busses/i2c-amd-mp2-pci.c

···
 static int amd_mp2_pci_init(struct amd_mp2_dev *privdata,
 			    struct pci_dev *pci_dev)
 {
-	int rc;
+	int irq_flag = 0, rc;
 
 	pci_set_drvdata(pci_dev, privdata);
 
···
 	if (rc)
 		goto err_dma_mask;
 
-	/* Set up intx irq */
+	/* request and enable interrupt */
 	writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
-	pci_intx(pci_dev, 1);
-	rc = devm_request_irq(&pci_dev->dev, pci_dev->irq, amd_mp2_irq_isr,
-			      IRQF_SHARED, dev_name(&pci_dev->dev), privdata);
-	if (rc)
-		pci_err(pci_dev, "Failure requesting irq %i: %d\n",
-			pci_dev->irq, rc);
+	rc = pci_alloc_irq_vectors(pci_dev, 1, 1, PCI_IRQ_ALL_TYPES);
+	if (rc < 0) {
+		dev_err(&pci_dev->dev, "Failed to allocate single IRQ err=%d\n", rc);
+		goto err_dma_mask;
+	}
+
+	privdata->dev_irq = pci_irq_vector(pci_dev, 0);
+	if (!pci_dev->msix_enabled && !pci_dev->msi_enabled)
+		irq_flag = IRQF_SHARED;
+
+	rc = devm_request_irq(&pci_dev->dev, privdata->dev_irq,
+			      amd_mp2_irq_isr, irq_flag, dev_name(&pci_dev->dev), privdata);
+	if (rc) {
+		pci_err(pci_dev, "Failure requesting irq %i: %d\n", privdata->dev_irq, rc);
+		goto free_irq_vectors;
+	}
 
 	return rc;
 
+free_irq_vectors:
+	free_irq(privdata->dev_irq, privdata);
 err_dma_mask:
 	pci_clear_master(pci_dev);
 err_pci_enable:
···
 	pm_runtime_forbid(&pci_dev->dev);
 	pm_runtime_get_noresume(&pci_dev->dev);
 
-	pci_intx(pci_dev, 0);
+	free_irq(privdata->dev_irq, privdata);
 	pci_clear_master(pci_dev);
 
 	amd_mp2_clear_reg(privdata);

drivers/i2c/busses/i2c-amd-mp2.h

···
 	struct mutex c2p_lock;
 	u8 c2p_lock_busid;
 	unsigned int probed;
+	int dev_irq;
 };
 
 /* PCIe communication driver */