I am attempting to utilize the DLN-2 in an x86_64 Linux environment (kernel version 4.18) to provide SPI and I2C bus controllers to the userspace, in a similar manner you would using an ARM platform with DTS/DTB file modifications. I am having trouble identifying the proper method to attach a SPI slave device or mount the device to userspace with the spidev driver.
The kernel modules are loading successfully and the SPI bus is mounted as a spi_master. I am certain the chip itself is working because the I2C (/dev/i2c-#) and GPIO (/dev/gpiochip#) interfaces can be successfully manipulated. For reference, here is a list of all references in the Linux system tree for "dln":
# find /sys -name *dln*
/sys/devices/pci0000:00/0000:00:15.0/usb1/1-2/1-2:1.0/dln2-i2c.1.auto
/sys/devices/pci0000:00/0000:00:15.0/usb1/1-2/1-2:1.0/dln2-spi.2.auto
/sys/devices/pci0000:00/0000:00:15.0/usb1/1-2/1-2:1.0/dln2-gpio.0.auto
/sys/fs/selinux/booleans/minidlna_read_generic_user_content
/sys/bus/platform/devices/dln2-i2c.1.auto
/sys/bus/platform/devices/dln2-spi.2.auto
/sys/bus/platform/devices/dln2-gpio.0.auto
/sys/bus/platform/drivers/dln2-gpio
/sys/bus/platform/drivers/dln2-gpio/dln2-gpio.0.auto
/sys/bus/platform/drivers/dln2-adc
/sys/bus/platform/drivers/dln2-spi
/sys/bus/platform/drivers/dln2-spi/dln2-spi.2.auto
/sys/bus/platform/drivers/dln2-i2c
/sys/bus/platform/drivers/dln2-i2c/dln2-i2c.1.auto
/sys/bus/usb/drivers/dln2
/sys/module/i2c_dln2
/sys/module/i2c_dln2/drivers/platform:dln2-i2c
/sys/module/industrialio_triggered_buffer/holders/dln2_adc
/sys/module/spi_dln2
/sys/module/spi_dln2/drivers/platform:dln2-spi
/sys/module/industrialio/holders/dln2_adc
/sys/module/dln2_adc
/sys/module/dln2_adc/drivers/platform:dln2-adc
/sys/module/gpio_dln2
/sys/module/gpio_dln2/drivers/platform:dln2-gpio
/sys/module/dln2
/sys/module/dln2/holders/i2c_dln2
/sys/module/dln2/holders/spi_dln2
/sys/module/dln2/holders/dln2_adc
/sys/module/dln2/holders/gpio_dln2
/sys/module/dln2/drivers/usb:dln2
Here is the matching portion of the boot log:
[ 1.578110] usb 1-2: new full-speed USB device number 2 using xhci_hcd
[ 1.705306] usb 1-2: New USB device found, idVendor=a257, idProduct=2013, bcdDevice= 1.00
[ 1.705310] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 1.705312] usb 1-2: Product: Diolan DLN2
[ 1.705314] usb 1-2: Manufacturer: Diolan
[ 10.485997] dln2 1-2:1.0: Diolan DLN2 serial 33632920
[ 10.486182] usbcore: registered new interface driver dln2
And the relevant portion of the usb device tree:
Bus 001 Device 002: ID a257:2013
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 255 Vendor Specific Class
bDeviceSubClass 255 Vendor Specific Subclass
bDeviceProtocol 255 Vendor Specific Protocol
bMaxPacketSize0 64
idVendor 0xa257
idProduct 0x2013
bcdDevice 1.00
iManufacturer 1 Diolan
iProduct 2 Diolan DLN2
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 0x0020
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x03 EP 3 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
can't get device qualifier: Resource temporarily unavailable
can't get debug descriptor: Resource temporarily unavailable
Device Status: 0x0000
(Bus Powered)
At this point, I am assuming that an ACPI patch is the correct method. however, the device does not appear in the ACPI device tree, or I am not searching with the correct string. I am assuming it will be similar to the following, which I pulled from a kernel patch (https://lore.kernel.org/patchwork/patch/527210/) that appears to have since been removed from the current kernel.
DefinitionBlock ("dln2.aml", "SSDT", 1, "INTEL", "CpuDptf", 3)
{
Device (DLN0)
{
Name (_ADR, Zero)
Name (_HID, "DLN2000")
Device (TP40) {
Name (_HID, "SPT0001")
Name (_DDN, "SPI4-CS0")
Name (_CRS, ResourceTemplate () {
SpiSerialBus (
1, // Chip select
PolarityLow, // Chip select is active low
FourWireMode, // Full duplex
8, // Bits per word is 8 (byte)
ControllerInitiated, // Don't care
1000000, // 1 MHz
ClockPolarityLow, // SPI mode 0
ClockPhaseFirst, // SPI mode 0
"\\DLN0.SPI0", // SPI host controller
0 // Must be 0
)
})
}
}
}
I have also tried udev rules, but my knowledge of udev is slim so they are likely incorrect. None of these appeared to have done the trick:
DEVPATH=="/devices/pci0000:00/0000:00:15.0/usb1/1-2/1-2:1.0/dln2-spi.2.auto/spi_master/spi0", DRIVER="spidev"
DEVPATH=="/devices/pci0000:00/0000:00:15.0/usb1/1-2/1-2:1.0/dln2-spi.2.auto/spi_master/spi0", KERNEL="spi-SPT0001:02", SUBSYSTEM="spi", DRIVER="spidev", ATTRS{driver_override}==""
DEVPATH=="/devices/pci0000:00/0000:00:15.0/usb1/1-2/1-2:1.0/dln2-spi.2.auto/spi_master/spi0/spi-SPT0001:02", KERNEL="spidev2.0", SUBSYSTEM="spidev", DRIVER=""
