How to Enable FlexCAN in device tree on iMX6QP custom board

[kishorr]

I am trying to enable FlexCAN bus 1 and 2 on iMX6QP based custom hardware.
The two CAN buses are connected from iMX6 as below

GPIO_7    : CAN-TX1
GPIO_8    : CAN-RX1
GPIO-4-5  : CAN-STBY1

KEY_COL4 : CAN-TX2
KEY_ROW4 : CAN-RX2
GPIO-6-10 : CAN-STBY2

The device tree is defined as below:
arch/arm/boot/dts/imx6qdl.dtsi
================================

/ {
        aliases {
                flexcan0 = &flexcan1;
                flexcan1 = &flexcan2;
                gpio0 = &gpio1;
...
...

  soc {
                #address-cells = <1>;
                #size-cells = <1>;
                compatible = "simple-bus";
                interrupt-parent = <&intc>;
                ranges;

                caam_sm: caam-sm@00100000 {
                        compatible = "fsl,imx6q-caam-sm";
                        reg = <0x00100000 0x3fff>;
                };

     flexcan1: 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 = "enabled";
                        };

    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 = "enabled";
                        };

arch/arm/boot/dts/imx6q.dtsi
=====================

&flexcan1 {
                 pinctrl_flexcan1_1: flexcan1grp {
                fsl,pins = <
                        MX6QDL_PAD_GPIO_7__FLEXCAN1_TX          0x1b0b0
                        MX6QDL_PAD_GPIO_8__FLEXCAN1_RX          0x1b0b0
                >;
        };
};

&flexcan2 {
        pinctrl_flexcan2_1: flexcan2grp {
                fsl,pins = <
                        MX6QDL_PAD_KEY_COL4__FLEXCAN2_TX        0x1b0b0
                        MX6QDL_PAD_KEY_ROW4__FLEXCAN2_RX        0x1b0b0
                >;
        };

};

arch/arm/boot/dts/imx6q-sabresd.dts
===================================

&flexcan1 {

         status = "okay";
};

&flexcan2 {

         status = "okay";
};

I observe CAN0 and CAN1 interfaces are up.
root@QPU2:~# ifconfig can0
can0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
          UP RUNNING NOARP  MTU:16  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:10
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:142

root@QPU2:~# ifconfig can1
can1      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
          UP RUNNING NOARP  MTU:16  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:10
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:143

I have connected both the CAN ports to KOMODO CAN analyser. When I send packets I do not see any packets sent out from either of the ports. I have run the internal loopback test which is successful.

ip link set can0 up type can bitrate 125000
ifconfig can0 up
ifconfig can0
cansend can0 100#1122334455667788

I suspect some issue with the device tree configuration. Appreciate if anyone could provide some pointers to the problem I am facing.

Thanks
Kishor

[kishorr]

Hi Igor,

The issue is resolved, It turns out to be the pinctrls are not placed inside the iomuxc node in dtsi file.

Thanks you.

Kishor

[rogerlee0212]

Hi  kishor 

      Can U share your  dtsi file ?

      my flexcan on MCIMX6Q-SDB  RevC4   doesn't work, what should I do now? 

---------------------

U-Boot 2014.04-08637-gaffa032 (Dec 01 2016 - 12:25:25)

CPU: Freescale i.MX6Q rev1.2 at 792 MHz
CPU: Temperature 22 C, calibration data: 0x5a04f57d#
Reset cause: POR
Board: MX6-SabreSD

-----------------------------

Linux version 3.10.17 (root@localhost-desktop) (gcc version 4.8.3 20140401 (prerelease) (crosstool-NG linaro-1.13.1-4.8-2014.04 - Linaro GCC 4.8-2014.04) ) #12 SMP PREEMPT Mon Oct 24 11:34:41 CST 2016

---------------------------------------

[/] # dmesg |grep can
pci_bus 0000:00: scanning bus
pci 0000:00:00.0: scanning [bus 01-01] behind bridge, pass 0
pci 0000:00:00.0: scanning [bus 00-00] behind bridge, pass 1
pci_bus 0000:01: scanning bus
pci_bus 0000:01: bus scan returning with max=01
pci_bus 0000:00: bus scan returning with max=01
ahci: SSS flag set, parallel bus scan disabled
flexcan 2090000.can: device registered (reg_base=c0a68000, irq=142)
can: controller area network core (rev 20120528 abi 9)
can: raw protocol (rev 20120528)
can: broadcast manager protocol (rev 20120528 t)
can: netlink gateway (rev 20130117) max_hops=1
[/] # /bin/ip link set can0 up type can bitrate 5000
flexcan 2090000.can can0: writing ctrl=0xf93e2007
[/] # ifconfig can0
can0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
UP RUNNING NOARP MTU:16 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:10
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
Interrupt:142

[/] #

[/] # /bin/ip -s -d link show can0
2: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN qlen 10
link/can
can state ERROR-ACTIVE (berr-counter tx 0 rx 0) restart-ms 0
bitrate 5000 sample-point 0.708
tq 8333 prop-seg 8 phase-seg1 8 phase-seg2 7 sjw 1
flexcan: tseg1 4..16 tseg2 2..8 sjw 1..4 brp 1..256 brp-inc 1
clock 30000000
re-started bus-errors arbit-lost error-warn error-pass bus-off
0 0 0 0 0 0
RX: bytes packets errors dropped overrun mcast
0 0 0 0 0 0
TX: bytes packets errors dropped carrier collsns
0 0 0 0 0 0
[/] # /bin/ip -s -d link show can0
2: can0: <NOARP,UP,LOWER_UP,ECHO> mtu 16 qdisc pfifo_fast state UNKNOWN qlen 10
link/can
can state ERROR-WARNING (berr-counter tx 0 rx 129) restart-ms 0
bitrate 5000 sample-point 0.708
tq 8333 prop-seg 8 phase-seg1 8 phase-seg2 7 sjw 1
flexcan: tseg1 4..16 tseg2 2..8 sjw 1..4 brp 1..256 brp-inc 1
clock 30000000
re-started bus-errors arbit-lost error-warn error-pass bus-off
0 0 0 1 0 0
RX: bytes packets errors dropped overrun mcast
8 1 0 0 0 0
TX: bytes packets errors dropped carrier collsns
0 0 0 0 0 0
[/] # /opt/imx6/app/can/cansend can0 100#1122334455667788
interface = can0, family = 29, type = 3, proto = 1
[/] #
[/] #
[/] # /bin/ip -s -d link show can0
2: can0: <NO-CARRIER,NOARP,UP,ECHO> mtu 16 qdisc pfifo_fast state DOWN qlen 10
link/can
can state BUS-OFF (berr-counter tx 0 rx 0) restart-ms 0
bitrate 5000 sample-point 0.708
tq 8333 prop-seg 8 phase-seg1 8 phase-seg2 7 sjw 1
flexcan: tseg1 4..16 tseg2 2..8 sjw 1..4 brp 1..256 brp-inc 1
clock 30000000
re-started bus-errors arbit-lost error-warn error-pass bus-off
0 0 0 1 1 1
RX: bytes packets errors dropped overrun mcast
24 3 0 0 0 0
TX: bytes packets errors dropped carrier collsns
0 0 0 0 0 0
[/] #

--------------------debugfs info-----------------------

9 mount -t debugfs none /sys/kernel/debug/
10 cd /sys/kernel/debug/
11 ll
12 cd pinctrl/
13 ll
14 cd 20e0000.iomuxc/
15 ll
16 cat pinconf-pins
17 cat pinmux-pins
18 cat pinmux-functions
19 cat pins
20 cat pingroups
21 cat pinconf-groups
22 cat pinconf-config
23 cat gpio-ranges

pin 149 (MX6Q_PAD_GPIO_19):0x1b0b0

pin 144 (MX6Q_PAD_GPIO_7): 2090000.can (GPIO UNCLAIMED) function flexcan1 group flexcan1grp
pin 145 (MX6Q_PAD_GPIO_8): 2090000.can (GPIO UNCLAIMED) function flexcan1 group flexcan1grp

pin 149 (MX6Q_PAD_GPIO_19): 2090000.can (GPIO UNCLAIMED) function flexcan1 group flexcan1grp

function: flexcan1, groups = [ flexcan1grp ]

pin 144 (MX6Q_PAD_GPIO_7) 20e0000.iomuxc
pin 145 (MX6Q_PAD_GPIO_8) 20e0000.iomuxc

pin 149 (MX6Q_PAD_GPIO_19) 20e0000.iomuxc

group: flexcan1grp
pin 144 (MX6Q_PAD_GPIO_7)
pin 145 (MX6Q_PAD_GPIO_8)
pin 149 (MX6Q_PAD_GPIO_19)

[rogerlee0212]

Finally, we found is that the chip TJA1040T is not working properly.

Flexcan works well after we use SN65HVD233

thx, kishorr

[kishorr]

I have tested internal loopback and works. Right now I have connected the CAN ports to KOMODO unit.

[igorpadykov]

what is about external loopback, is it working.

[kishorr]

Thanks igor.

I have updated the device tree files. But still not able to send any packets on can0 or can1 interfaces.

Just providing the device tree info for reference:

arch/arm/boot/dts/imx6q.dtsi:

&flexcan1 {
       pinctrl_flexcan1_1: flexcan1grp-1 {
                fsl,pins = <
                        MX6QDL_PAD_GPIO_7__FLEXCAN1_TX          0x1b0b0
                        MX6QDL_PAD_GPIO_8__FLEXCAN1_RX          0x1b0b0
                        MX6QDL_PAD_GPIO_19__GPIO4_IO05          0x1b0b0
                        >;
                };
};

&flexcan2 {
        pinctrl_flexcan2_1: flexcan2grp-2 {
                fsl,pins = <
                        MX6QDL_PAD_KEY_COL4__FLEXCAN2_TX        0x1b0b0
                        MX6QDL_PAD_KEY_ROW4__FLEXCAN2_RX        0x1b0b0
                        MX6QDL_PAD_NAND_RB0__GPIO6_IO10              0x1b0b0
                        >;
         };

arch/arm/boot/dts/imx6qdl.dtsi:

  flexcan1: 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 = "disabled";
                        };

                        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 = "disabled";
                        };

arch/arm/boot/dts/imx6q-sabresd.dts

&flexcan1 {
         pinctrl-names = "default";
         pinctrl-0 = <&pinctrl_flexcan1_1>;
         trx-stby-gpio = <&gpio4 5 GPIO_ACTIVE_LOW>;
         status = "okay";
};

&flexcan2 {
         pinctrl-names = "default";
         pinctrl-0 = <&pinctrl_flexcan2_1>;
         trx-stby-gpio = <&gpio6 10 GPIO_ACTIVE_LOW>;
         status = "okay";
};

&fec {
        status = "disabled";
};

When I send a packet using cansend utility I see debug messages from flexcan_start_xmit

but flexcan_irq is not getting triggered.

I see below messages in the kernel initialization:

2090000.can supply xceiver not found, using dummy regulator
2094000.can supply xceiver not found, using dummy regulator

we are using 33901 Can Tranceiver.

root@U2:~# ifconfig
can0      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
          UP RUNNING NOARP  MTU:16  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:10
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:142

can1      Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
          UP RUNNING NOARP  MTU:16  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:10
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:143

after sending 10 packets i see the below message

root@U2:~# cansend can0 100#1122334455667788
write: No buffer space available

Any idea whats going on.

Thanks

Kishor

[igorpadykov]

Hi Kishor

is it working with loopback test, as without connection can to
some another can, it will not work (it will consider line as busy).

Best regards
igor

[igorpadykov]

Hi Kishor

can is used on sabre ai board and one can check imx6qp-sabreauto-flexcan1.dts, imx6qdl.dtsi settings:
http://git.freescale.com/git/cgit.cgi/imx/linux-imx.git/tree/arch/arm/boot/dts/imx6qdl.dtsi?id=rel_i...
http://git.freescale.com/git/cgit.cgi/imx/linux-imx.git/tree/arch/arm/boot/dts/imx6qp-sabreauto-flex...

test details are described in imx-test (folder ..test/can)
www.nxp.com/lgfiles/NMG/MAD/YOCTO/imx-test-5.7.tar.gz

Best regards
igor
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