ksz8795 spi_master spi0: spi_device register error

mahendrasondaga · ‎06-02-2023

Hello there,
Hope all are doing well

I'm dealing with the i.mx6-based SOM with my custom hardware
I'm using ksz8795 4 port Ethernet switch with using spi

For instance, I'm using Yocto Hardknott BSP provided by Variscite as my SOM is from Variscite

The device tree configuration is as follows

&ecspi1 {

		 fsl,spi-num-chipselects = <1>;
		//cs-gpios = <&gpio4 26 0>;
                 pinctrl-names = "default";
        	 pinctrl-0 = <&pinctrl_ecspi1_1>;
        	 status = "okay";

               chip1: spidev@0 {
	               compatible = "var,spidev";
        	       spi-max-frequency = <25000000>;
               	       reg = <0>;
                       status = "okay";
                     };

                      ksz8795@0 {
                      
                         compatible = "microchip,ksz8795";
                         spi-max-frequency = <25000000>;
                         reg = <0>;
                         pinctrl-names = "default";
                         cs-gpios = <&gpio4 26 0>;
                         reset-gpios = <&gpio5 5 0>;
                         status = "okay";

                        //spi-cpha;
                        //spi-cpol;
                       ports {
                             #address-cells = <1>;
                             #size-cells = <0>;
                             port@0 {
                                    reg = <0>;
                                    label = "lan1";
                             };
                             port@1 {
                                    reg = <1>;
                                    label = "lan2";
                             };
                             port@2 {
                                    reg = <2>;
                                    label = "lan3";
                             };
                             port@3 {
                                    reg = <3>;
                                    label = "lan4";
                             };
                             port@4 {
                                    reg = <4>;
                                    label = "cpu";
                                    ethernet = <&fec2>;
                                    fixed-link {
                                               speed = <100>;
                                               full-duplex;
                                    };
                             };
                       };
                   };
};

Apart from that, I have also activated all necessary drivers from the menu config as follows

CONFIG_NET_DSA=y
CONFIG_NET_DSA_TAG_KSZ=y
CONFIG_NET_DSA_MICROCHIP_KSZ8795=m
CONFIG_NET_DSA_MICROCHIP_KSZ_COMMON=m
CONFIG_NET_DSA_MICROCHIP_KSZ8795_SPI=m
CONFIG_REGMAP_SPI=y

For me, the SPI is working well
However, during the boo time, I got the following errors, and ksz8795 drivers were unable to activate!

root@imx6ul-var-dart:~# dmesg | grep spi
[    2.324211] spi_imx 2008000.spi: registered master spi0
[    2.324649] spi spi0.0: spi_imx_setup: mode 0, 8 bpw, 25000000 hz
[    2.324688] spi spi0.0: setup mode 0, 8 bits/w, 25000000 Hz max --> 0
[    2.325946] spi_imx 2008000.spi: registered child spi0.0
[    2.326022] spi_imx 2008000.spi: chipselect 0 already in use
[    2.331997] spi_master spi0: spi_device register error /soc/bus@2000000/spba-bus@2000000/spi@2008000/ksz8795@0
[    2.342136] spi_master spi0: Failed to create SPI device for /soc/bus@2000000/spba-bus@2000000/spi@2008000/ksz8795@0

seems like CS line is utilizing by the spidev

Can anyone help me here?
For more information, I have attached dmesg logs here

All suggestions and comments are welcome

Thanks

Mahendra

mahendrasondaga · ‎06-15-2023

Hi.. @Zhiming_Liu
First of all Thanks for the feedback

I got some progress out of it

Here are the steps that I performed to debug the issue

1. I wanted to use the SPI to communicate with the ksz8795 and CPU port of the LAN controller is connected with the FEC2
That's how i'd removed MDIO section from the FEC2

The new updated DTS files are as follows

    &ecspi1 {

                 fsl,spi-num-chipselects = <1>;
                 cs-gpios = <&gpio4 26 GPIO_ACTIVE_LOW>;
                 pinctrl-names = "default";
                 pinctrl-0 = <&pinctrl_ecspi1_1>;
                 status = "okay";

                      ksz8795@0 {                      
                         compatible = "microchip,ksz8795";
                         spi-max-frequency = <25000000>;
                         reg = <0>;
                         pinctrl-names = "default";
                         status = "okay";

                       ports {
                             #address-cells = <1>;
                             #size-cells = <0>;
                             port@0 {
                                    reg = <0>;
                                    label = "lan1";
                             };
                             port@1 {
                                    reg = <1>;
                                    label = "lan2";
                             };
                             port@2 {
                                    reg = <2>;
                                    label = "lan3";
                             };
                             port@3 {
                                    reg = <3>;
                                    label = "lan4";
                             };
                             port@4 {
                                    reg = <4>;
                                    label = "cpu";
                                    ethernet = <&fec2>;
                                    fixed-link {
                                               speed = <100>;
                                               full-duplex;
                                    };
                             };
                       };
                   };
};
       
/* AIO ETH switch node update */
&fec2 {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_enet2>, <&pinctrl_enet2_gpio>
        phy-mode = "rmii";
        phy-reset-gpios=<&gpio5 5 GPIO_ACTIVE_LOW>;
        phy-reset-duration=<100>;
        status = "okay";

        
        fixed-link {
                      speed = <100>;
                      full-duplex;
           };
};

2. Erlear I was using the spidev to debug the SPI communication. But once I confirmed that the SPI communication is working well then I removed it from the DTS sub-node as you can see from the above DTS snippets

Because spidev and KSZ8795 are using the same CS pin of the SPI and that's how it was conflicting!

Right now I have completely removed the spidev subnode from the ecspi1 parent node

3. All supported drivers of the KSZ8795 were selected as the dynamically loadable modules from the menuconfig
But somehow it was not installed with the custom image

As i'd confirmed by checking the "/lib/modules" directory on my custom board

The reason is CORE_IMAGE_EXTRA_INSTALL += " kernel-modules" was missing in to my local.conf file
By adding it I can see that the drivers are available in "/lib/modules/5.10.72+gb9b6d7d06d4a/kernel/drivers/net/dsa/microchip" directory

The listed drivers are ksz8795.ko ksz8795_spi.ko and ksz_common.ko

4. Finally, now FEC2 is communicating with ksz8795 if I consider the following logs from my kernel

[   17.902843] Generic PHY fixed-0:00: attached PHY driver [Generic PHY] (mii_bus:phy_addr=fixed-0:00, irq=POLL)
[   17.951773] fec 20b4000.ethernet eth0: Link is Up - 100Mbps/Full - flow control off
[   17.997825] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready

5. From the observation of the lsmod command, I can see that the ksz drivers were not automatically loading upon boot
The reason is KERNEL_MODULE_AUTOLOAD variable was missing in to local.conf

That's how, i'd specified It as follows

KERNEL_MODULE_AUTOLOAD += "ksz_common ksz8795_spi ksz8795"

6. Now from the kernel logs, I can see that the ksz8795 driver forcefully try to load upon boot
However, it met with the SPI error
here are the Error logs......

root@imx6ul-var-dart:~# dmesg | grep spi
[    2.270526] spi_imx 2008000.spi: registered master spi0
[    2.270963] spi spi0.0: spi_imx_setup: mode 0, 8 bpw, 20000000 hz
[    2.271002] spi spi0.0: setup mode 0, 8 bits/w, 20000000 Hz max --> 0
[    2.271959] spi_imx 2008000.spi: registered child spi0.0
[    7.672984] spi_imx 2008000.spi: mx51_ecspi_clkdiv: fin: 60000000, fspi: 20000000, post: 0, pre: 2
[    7.673040] spi_imx 2008000.spi: mx51_ecspi_clkdiv: fin: 60000000, fspi: 20000000, post: 0, pre: 2
[    7.675620] ksz8795-switch: probe of spi0.0 failed with error -22

The error code "-22" typically corresponds to the EINVAL error, which stands for "Invalid argument."

Guys, Any suggestions?
Welcome all suggestions and comments

I have attached the latest kernel logs here

Thanks

Mahendra

Zhiming_Liu · ‎06-20-2023

Hi @mahendrasondaga

I can't find error log in the attachment, please attach demsg log.

mahendrasondaga · ‎06-25-2023

Hi..
pl. find the dmesg logs from here

Recently, instead of using the loadable kernel modules, i have try with the loading the modules statically with the image itself

mahendrasondaga · ‎06-03-2023

Hi... there
Here is the further investigation and effort from my side

1. Disabled spidev sub-node to overcome the CS line occupying issue

2. KSZ8795 Ethernet switch has the 5 ports of of that, the 5th port is connected with the CPU ENET2 i.e FEC2

here is the DST node for the FEC2

&fec2 {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_enet2>, <&pinctrl_enet2_gpio>, <&pinctrl_enet2_mdio>;
        phy-mode = "rmii";
        phy-handle = <&ethphy1>;
        phy-reset-gpios=<&gpio5 5 GPIO_ACTIVE_LOW>;
        phy-reset-duration=<100>;
        status = "okay";

        mdio {
                #address-cells = <1>;
                #size-cells = <0>;

                ethphy0: ethernet-phy@1 {
                        compatible = "ethernet-phy-ieee802.3-c22";
                        micrel,rmii-reference-clock-select-25-mhz;
                        micrel,led-mode = <1>;
                        clocks = <&rmii_ref_clk>;
                        clock-names = "rmii-ref";
                        reg = <1>;
                };

                ethphy1: ethernet-phy@3 {
                        compatible = "ethernet-phy-ieee802.3-c22";
                        micrel,rmii-reference-clock-select-25-mhz;
                        micrel,led-mode = <0>;
                        clocks = <&rmii_ref_clk>;
                        clock-names = "rmii-ref";
                        reg = <3>;
                };
        };
};

3. SPI & MDIO directories are also populated

root@imx6ul-var-dart:/sys/bus/spi/devices/spi0.0# ls
consumers  driver_override  modalias  of_node  power  statistics  subsystem  supplier:platform:20a8000.gpio  supplier:platform:20ac000.gpio  suppliers  uevent

root@imx6ul-var-dart:/sys/bus/mdio_bus/devices/20b4000.ethernet-1:01# cd of_node
root@imx6ul-var-dart:/sys/bus/mdio_bus/devices/20b4000.ethernet-1:01/of_node# ls
clock-names  clocks  compatible  micrel,led-mode  micrel,rmii-reference-clock-select-25-mhz  name  phandle  reg
root@imx6ul-var-dart:/sys/bus/mdio_bus/devices/20b4000.ethernet-1:01/of_node#

The Error logs are as follows

root@imx6ul-var-dart:~# dmesg | grep eth0
[    2.488402] fec 20b4000.ethernet eth0: registered PHC device 0
[   17.446500] fec 20b4000.ethernet eth0: Unable to connect to phy
[   19.404484] fec 20b4000.ethernet eth0: Unable to connect to phy

I have also attached the new dmesg logs here

Thanks

Zhiming_Liu · ‎06-08-2023

Hello @mahendrasondaga

From your log. there should be something missed or incorrect in your dts. You can trace phy_connect_direct in of_phy_connect and fec_enet_adjust_link to figure out where it failed.