/**********************************************************************                  flexcan controller register* 说明：*     由于设备树没有正确注册CAN控制器设备，导致内核没有生产CAN设备。* 另外就是在调试阶段可以make menuconfig加上can debug信息，如果需要* 内核支持vcan，也需要通过make menuconfig来对其进行支持。**                                   2017-8-15 深圳 龙华樟坑村 曾剑锋********************************************************************/一、参考文档：1. device tree can controller status settinghttps://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/net/can/c_can.txt2. fsl-flexcan.txthttps://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/net/can/fsl-flexcan.txt

二、处理方法：1. 设备树路径：arch/arm/boot/dts/imx6qdl.dtsiflexcan1: can@02090000 {compatible = "fsl,imx6q-flexcan";reg = <0x02090000 0x4000>;interrupts = <0 110 IRQ_TYPE_LEVEL_HIGH>;clocks = <&clks IMX6QDL_CLK_CAN1_IPG>,<&clks IMX6QDL_CLK_CAN1_SERIAL>;clock-names = "ipg", "per";stop-mode = <&gpr 0x34 28 0x10 17>;status = "okay";    /* change disable to okay */};flexcan2: can@02094000 {compatible = "fsl,imx6q-flexcan";reg = <0x02094000 0x4000>;interrupts = <0 111 IRQ_TYPE_LEVEL_HIGH>;clocks = <&clks IMX6QDL_CLK_CAN2_IPG>,<&clks IMX6QDL_CLK_CAN2_SERIAL>;clock-names = "ipg", "per";stop-mode = <&gpr 0x34 29 0x10 18>;status = "okay";    /* change disable to okay */};2. 查看CAN设备：root@freescale ~$ ifconfig -acan0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00NOARP  MTU:16  Metric:1RX packets:0 errors:0 dropped:0 overruns:0 frame:0TX packets:0 errors:0 dropped:0 overruns:0 carrier:0collisions:0 txqueuelen:10RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)Interrupt:142can1      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00NOARP  MTU:16  Metric:1RX packets:0 errors:0 dropped:0 overruns:0 frame:0TX packets:0 errors:0 dropped:0 overruns:0 carrier:0collisions:0 txqueuelen:10RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)Interrupt:143...root@freescale ~$