serial: 8250_exar: Add support for USR298x PCI Modems

commit 95d6988 upstream.

Possibly the last PCI controller-based (i.e. not a soft/winmodem)
dial-up modem one can still buy.

Looks to have a stock XR17C154 PCI UART chip for communication, but for
some reason when provisioning the PCI IDs they swapped the vendor and
subvendor IDs. Otherwise this card would have worked out of the box.

Searching online, some folks seem to not have this issue and others do,
so it is possible only some batches of cards have this error.

Create a new macro to handle the switched IDs and add support here.

Signed-off-by: Andrew Davis <afd@ti.com>
Cc: stable <stable@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230420160209.28221-1-afd@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_exar.c

@@ -40,9 +40,13 @@
 #define PCI_DEVICE_ID_COMMTECH_4224PCIE		0x0020
 #define PCI_DEVICE_ID_COMMTECH_4228PCIE		0x0021
 #define PCI_DEVICE_ID_COMMTECH_4222PCIE		0x0022
+
 #define PCI_DEVICE_ID_EXAR_XR17V4358		0x4358
 #define PCI_DEVICE_ID_EXAR_XR17V8358		0x8358
 
+#define PCI_SUBDEVICE_ID_USR_2980		0x0128
+#define PCI_SUBDEVICE_ID_USR_2981		0x0129
+
 #define PCI_DEVICE_ID_SEALEVEL_710xC		0x1001
 #define PCI_DEVICE_ID_SEALEVEL_720xC		0x1002
 #define PCI_DEVICE_ID_SEALEVEL_740xC		0x1004
@@ -829,6 +833,15 @@ static const struct exar8250_board pbn_exar_XR17V8358 = {
 		(kernel_ulong_t)&bd			\
 	}
 
+#define USR_DEVICE(devid, sdevid, bd) {			\
+	PCI_DEVICE_SUB(					\
+		PCI_VENDOR_ID_USR,			\
+		PCI_DEVICE_ID_EXAR_##devid,		\
+		PCI_VENDOR_ID_EXAR,			\
+		PCI_SUBDEVICE_ID_USR_##sdevid), 0, 0,	\
+		(kernel_ulong_t)&bd			\
+	}
+
 static const struct pci_device_id exar_pci_tbl[] = {
 	EXAR_DEVICE(ACCESSIO, COM_2S, pbn_exar_XR17C15x),
 	EXAR_DEVICE(ACCESSIO, COM_4S, pbn_exar_XR17C15x),
@@ -853,6 +866,10 @@ static const struct pci_device_id exar_pci_tbl[] = {
 
 	IBM_DEVICE(XR17C152, SATURN_SERIAL_ONE_PORT, pbn_exar_ibm_saturn),
 
+	/* USRobotics USR298x-OEM PCI Modems */
+	USR_DEVICE(XR17C152, 2980, pbn_exar_XR17C15x),
+	USR_DEVICE(XR17C152, 2981, pbn_exar_XR17C15x),
+
 	/* Exar Corp. XR17C15[248] Dual/Quad/Octal UART */
 	EXAR_DEVICE(EXAR, XR17C152, pbn_exar_XR17C15x),
 	EXAR_DEVICE(EXAR, XR17C154, pbn_exar_XR17C15x),