ACPI: Allow a WAN module enable/disable on a Thinkpad X60.

The WAN (Sierra Wireless EV-DO) module is very similar to the
Bluetooth module.  It appears on the USB bus when enabled.  It can be
controlled via hot key, or directly via ACPI.  This change enables
direct control via ACPI.

I have tested it on my Lenovo Thinkpad X60; I guess it will probably
work on other Thinkpad models which come with this module installed.

Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Ack'd by: Borislav Deianov <borislav@users.sf.net>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/ibm_acpi.c

@@ -567,6 +567,69 @@ static int bluetooth_write(char *buf)
 	return 0;
 }
 
+static int wan_supported;
+
+static int wan_init(void)
+{
+	wan_supported = hkey_handle &&
+	    acpi_evalf(hkey_handle, NULL, "GWAN", "qv");
+
+	return 0;
+}
+
+static int wan_status(void)
+{
+	int status;
+
+	if (!wan_supported ||
+	    !acpi_evalf(hkey_handle, &status, "GWAN", "d"))
+		status = 0;
+
+	return status;
+}
+
+static int wan_read(char *p)
+{
+	int len = 0;
+	int status = wan_status();
+
+	if (!wan_supported)
+		len += sprintf(p + len, "status:\t\tnot supported\n");
+	else if (!(status & 1))
+		len += sprintf(p + len, "status:\t\tnot installed\n");
+	else {
+		len += sprintf(p + len, "status:\t\t%s\n", enabled(status, 1));
+		len += sprintf(p + len, "commands:\tenable, disable\n");
+	}
+
+	return len;
+}
+
+static int wan_write(char *buf)
+{
+	int status = wan_status();
+	char *cmd;
+	int do_cmd = 0;
+
+	if (!wan_supported)
+		return -ENODEV;
+
+	while ((cmd = next_cmd(&buf))) {
+		if (strlencmp(cmd, "enable") == 0) {
+			status |= 2;
+		} else if (strlencmp(cmd, "disable") == 0) {
+			status &= ~2;
+		} else
+			return -EINVAL;
+		do_cmd = 1;
+	}
+
+	if (do_cmd && !acpi_evalf(hkey_handle, NULL, "SWAN", "vd", status))
+		return -EIO;
+
+	return 0;
+}
+
 static int video_supported;
 static int video_orig_autosw;
 
@@ -1562,6 +1625,13 @@ static struct ibm_struct ibms[] = {
 	 .read = bluetooth_read,
 	 .write = bluetooth_write,
 	 },
+	{
+	 .name = "wan",
+	 .init = wan_init,
+	 .read = wan_read,
+	 .write = wan_write,
+	 .experimental = 1,
+	 },
 	{
 	 .name = "video",
 	 .init = video_init,