PCI: altera-msi: Allow building as module

Altera MSI IP is a soft IP and is only available after
an FPGA image (with design containing it) is programmed.

Make driver modulable to support use case FPGA image is programmed the
after kernel has booted, so that the driver can be loaded upon request.

Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

2 files changed, 11 insertions, 1 deletions

diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index 89906351bd3f..fe9f9f13ce11 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -181,7 +181,7 @@ config PCIE_ALTERA
           FPGA.
 
 config PCIE_ALTERA_MSI
-        bool "Altera PCIe MSI feature"
+        tristate "Altera PCIe MSI feature"
         depends on PCIE_ALTERA
         depends on PCI_MSI_IRQ_DOMAIN
         help
diff --git a/drivers/pci/controller/pcie-altera-msi.c b/drivers/pci/controller/pcie-altera-msi.c
index 025ef7d9a046..16d938920ca5 100644
--- a/drivers/pci/controller/pcie-altera-msi.c
+++ b/drivers/pci/controller/pcie-altera-msi.c
@@ -10,6 +10,7 @@
 #include <linux/interrupt.h>
 #include <linux/irqchip/chained_irq.h>
 #include <linux/init.h>
+#include <linux/module.h>
 #include <linux/msi.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
@@ -288,4 +289,13 @@ static int __init altera_msi_init(void)
 {
         return platform_driver_register(&altera_msi_driver);
 }
+
+static void __exit altera_msi_exit(void)
+{
+        platform_driver_unregister(&altera_msi_driver);
+}
+
 subsys_initcall(altera_msi_init);
+MODULE_DEVICE_TABLE(of, altera_msi_of_match);
+module_exit(altera_msi_exit);
+MODULE_LICENSE("GPL v2");