can: sja1000: generic OF platform bus driver

This patch adds a generic driver for SJA1000 chips on the OpenFirmware
platform bus found on embedded PowerPC systems. You need a SJA1000 node
definition in your flattened device tree source (DTS) file similar to:

  can@3,100 {
  	compatible = "nxp,sja1000";
  	reg = <3 0x100 0x80>;
  	interrupts = <2 0>;
  	interrupt-parent = <&mpic>;
  	nxp,external-clock-frequency = <16000000>;
  };

See also Documentation/powerpc/dts-bindings/can/sja1000.txt.

CC: devicetree-discuss@ozlabs.org
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/can/platform/sja1000.h b/include/linux/can/platform/sja1000.h
index 37966e6..01ee2ae 100644
--- a/include/linux/can/platform/sja1000.h
+++ b/include/linux/can/platform/sja1000.h
@@ -13,6 +13,7 @@
 #define OCR_MODE_TEST     0x01
 #define OCR_MODE_NORMAL   0x02
 #define OCR_MODE_CLOCK    0x03
+#define OCR_MODE_MASK     0x07
 #define OCR_TX0_INVERT    0x04
 #define OCR_TX0_PULLDOWN  0x08
 #define OCR_TX0_PULLUP    0x10
@@ -21,6 +22,8 @@
 #define OCR_TX1_PULLDOWN  0x40
 #define OCR_TX1_PULLUP    0x80
 #define OCR_TX1_PUSHPULL  0xc0
+#define OCR_TX_MASK       0xfc
+#define OCR_TX_SHIFT      2
 
 struct sja1000_platform_data {
 	u32 clock;	/* CAN bus oscillator frequency in Hz */