spi: spidev: Add CAN controller and HSM support as spi slaves

Add compatible flags for CAN controller and HSM chip to use them
with the spidev driver from user space.

Change-Id: I154c29b6c912cac2560333ef635aa4a542fd1985
Signed-off-by: Gustavo Solaira <gustavos@codeaurora.org>

Documentation/devicetree/bindings/spi/spidev.txt

@@ -0,0 +1,30 @@
+SPIDEV
+
+SPI slave devices using the spidev driver allowing for userspace
+control of the SPI devices. Must be children of a SPI master node
+and contain the following properties.
+
+Required properties:
+- compatible:     Should contain:
+                  "nxp,mpc57xx" for external CAN controller
+                  "infineon,sli97" for external HSM module
+
+- reg:            Chip select address of device.
+- spi-max-frequency: Maximum SPI clocking speed of device in Hz.
+
+Optional properties:
+- spi-cpol:       Empty property indicating device requires
+                  inverse clock polarity (CPOL) mode.
+- spi-cpha:       Empty property indicating device requires
+                  shifted clock phase (CPHA) mode.
+
+Other optional properties described in
+Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Example:
+
+	spi@0 {
+		compatible = "nxp,mpc57xx";
+		reg = <0>;
+		spi-max-frequency = <19200000>;
+	};

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -114,6 +114,7 @@ ibm	International Business Machines (IBM)
 idt	Integrated Device Technologies, Inc.
 iom	Iomega Corporation
 img	Imagination Technologies Ltd.
+infineon	Infineon Technologies AG
 ingenic	Ingenic Semiconductor
 innolux	Innolux Corporation
 intel	Intel Corporation

drivers/spi/spidev.c

@@ -696,6 +696,8 @@ static const struct of_device_id spidev_dt_ids[] = {
 	{ .compatible = "rohm,dh2228fv" },
 	{ .compatible = "lineartechnology,ltc2488" },
 	{ .compatible = "qcom,spi-msm-codec-slave", },
+	{ .compatible = "nxp,mpc57xx", },
+	{ .compatible = "infineon,sli97", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, spidev_dt_ids);