USB: serial: mxuport: update number-of-ports encoding

In preparation for adding support for 3, 5, 6 and 7 port devices, replace
the current one-bit-per-type encoding of the number of ports with a more
compact four bit encoding (2..16 ports or undefined).

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/mxuport.c b/drivers/usb/serial/mxuport.c
index ad5fdf55a02e18a57a86205a3b7943a26cf2fac5..591be1fe3737c47798d600aa9850927bd8ad8c20 100644 (file)
--- a/drivers/usb/serial/mxuport.c
+++ b/drivers/usb/serial/mxuport.c
@@ -146,11 +146,6 @@
 #define MX_WAIT_FOR_LOW_WATER          0x0040
 #define MX_WAIT_FOR_SEND_NEXT          0x0080
 
-#define MX_UPORT_2_PORT                        BIT(0)
-#define MX_UPORT_4_PORT                        BIT(1)
-#define MX_UPORT_8_PORT                        BIT(2)
-#define MX_UPORT_16_PORT               BIT(3)
-
 /* This structure holds all of the local port information */
 struct mxuport_port {
        u8 mcr_state;           /* Last MCR state */
@@ -159,26 +154,31 @@ struct mxuport_port {
        spinlock_t spinlock;    /* Protects msr_state */
 };
 
+/* Encode number of ports (2..16 or undefined) */
+#define MX_PORTS_MASK                  GENMASK(3, 0)
+#define MX_PORTS_OFFSET                        1
+#define MX_PORTS(n)                    (((n) - MX_PORTS_OFFSET) & MX_PORTS_MASK)
+
 /* Table of devices that work with this driver */
 static const struct usb_device_id mxuport_idtable[] = {
        { USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1250_PID),
-         .driver_info = MX_UPORT_2_PORT },
+         .driver_info = MX_PORTS(2) },
        { USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1251_PID),
-         .driver_info = MX_UPORT_2_PORT },
+         .driver_info = MX_PORTS(2) },
        { USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1410_PID),
-         .driver_info = MX_UPORT_4_PORT },
+         .driver_info = MX_PORTS(4) },
        { USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1450_PID),
-         .driver_info = MX_UPORT_4_PORT },
+         .driver_info = MX_PORTS(4) },
        { USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1451_PID),
-         .driver_info = MX_UPORT_4_PORT },
+         .driver_info = MX_PORTS(4) },
        { USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1618_PID),
-         .driver_info = MX_UPORT_8_PORT },
+         .driver_info = MX_PORTS(8) },
        { USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1658_PID),
-         .driver_info = MX_UPORT_8_PORT },
+         .driver_info = MX_PORTS(8) },
        { USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1613_PID),
-         .driver_info = MX_UPORT_16_PORT },
+         .driver_info = MX_PORTS(16) },
        { USB_DEVICE(MX_USBSERIAL_VID, MX_UPORT1653_PID),
-         .driver_info = MX_UPORT_16_PORT },
+         .driver_info = MX_PORTS(16) },
        {}                      /* Terminating entry */
 };
 
@@ -942,14 +942,8 @@ static int mxuport_calc_num_ports(struct usb_serial *serial,
        int num_ports;
        int i;
 
-       if (features & MX_UPORT_2_PORT) {
-               num_ports = 2;
-       } else if (features & MX_UPORT_4_PORT) {
-               num_ports = 4;
-       } else if (features & MX_UPORT_8_PORT) {
-               num_ports = 8;
-       } else if (features & MX_UPORT_16_PORT) {
-               num_ports = 16;
+       if (features & MX_PORTS_MASK) {
+               num_ports = (features & MX_PORTS_MASK) + MX_PORTS_OFFSET;
        } else {
                dev_warn(&serial->interface->dev,
                                "unknown device, assuming two ports\n");