Common subdirectories: serial.orig/8250 and serial/8250
diff -u serial.orig/Kconfig serial/Kconfig
--- serial.orig/Kconfig	2014-09-20 08:54:08.265927400 +0900
+++ serial/Kconfig	2014-09-20 08:59:09.567868300 +0900
@@ -290,7 +290,7 @@
 	  MAX3100 chip support
 
 config SERIAL_MAX310X
-	bool "MAX310X support"
+	tristate "MAX310X support"
 	depends on SPI_MASTER
 	select SERIAL_CORE
 	select REGMAP_SPI if SPI_MASTER
Common subdirectories: serial.orig/cpm_uart and serial/cpm_uart
Common subdirectories: serial.orig/jsm and serial/jsm
diff -u serial.orig/max310x.c serial/max310x.c
--- serial.orig/max310x.c	2014-09-20 09:08:02.048870500 +0900
+++ serial/max310x.c	2014-09-20 09:06:59.009029300 +0900
@@ -1129,8 +1129,16 @@
 		   PTR_ERR(clk_xtal) == -EPROBE_DEFER) {
 		return -EPROBE_DEFER;
 	} else {
+#if 0
 		dev_err(dev, "Cannot get clock\n");
 		return -EINVAL;
+#else
+		dev_warn(dev, "Force using Xtal\n");
+		s->clk = clk_xtal; // dummy
+		freq = 3686400;
+		xtal = true;
+		goto clk_checked;
+#endif
 	}
 
 	ret = clk_prepare_enable(s->clk);
@@ -1144,6 +1152,7 @@
 		goto out_clk;
 	}
 
+	clk_checked:
 	s->regmap = regmap;
 	s->devtype = devtype;
 	dev_set_drvdata(dev, s);