If we enable gadget_only_mode under CONFIG_USB_MUSB_GADGET in our kernel or linux based device. if it will work as a gadget. Gadget means if I connect my device to my system then my device will listed as a gadget or as a sound card. I get confused because if we do enable any driver support in our kernel that module will be loaded when same supported device driver device will be connect. Please help me out we we do enable gadget only module in our kernel then if our device will work as a gadget??
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I developed a module DMA with some functions to be used when interact with kernel (IOCTL Function Usage) of zynq device.
I have inserted a DMA module into the zynq device but i am not sure if the device files have been created.
How can I find or create the corresponding device files in dev directory. Any help appreciated
The generated source code is similar to the following
I am new to creating a driver implementing.
My Application is using socketcan interface and apparently socketcan is not supported by the SOC.
I am planning to write my own driver. The issue I know how simple module for kernel I am not pretty sure where to start for socketcan driver .
If someone can please tell me where can I take reference for building the CAN driver or some git repo where can I use it and any specifics while writing the driver
SocketCan is the name of a Linux subsystem. It can be enabled in the kernel config via CONFIG_CAN. In turn, this subsystem will make use of platform-specific drivers to control the SOC's CAN adapters (if any).
If Linux's CAN subsystem is not enabled, make sure to enable CONFIG_CAN. If it is enabled, and no "can" device show up, the best would likely be to contact the SOC vendor for further guidance / drivers / devicetree / ... In any case, writing a custom driver is probably not necessary here.
Development platform: TI davinci processor with Linux OS
I am developing C program which receives user command over serial port and does the corresponding task. Basic task is to start and stop the video recording. And for retrieving the video to host pc from the embedded device, usb interface is used.
The partition used for storing the video file is loaded as USB gadget mass storage device using following kernel module for the user to save the video on host pc.
modprobe g_file_storage file=/root/usbstorage
But i want to load(or some otherway) this kernel module from the c function whenever user send a command to connect the embedded device to host. And disconnect whenever disconnect command is received.
As of now I'm able to load this module only from the shell.
Could any suggest any possible way of doing this from within the c-program.
I have an embedded Linux solution and want to create a command service over serial USB. The idea being that when a computer connects to my embedded via USB, they see a serial device and send serial commands to me through that port and I send responses back.
I need some help in the direction to proceed. Do I need to emulate a serial device so they see me as a COM port? Is there build in Linux solutions to broadcast my details as a serial device? Are there code examples? I can see block devices connect with my embedded solution like a USB storage device. When I plug into another computer, I would like it to see me as a serial COM port.
I just need help in the direction of which path I should go down to solve this.
Thanks in advance.
What you are looking for is the Linux USB serial gadget. The Linux USB gadgets framework allows devices to behave as a variety of standard USB devices, including serial devices, Ethernet adapters, and mass storage devices.
Note that USB gadgets will only work on targets with a USB controller that can be set to operate as a USB device. Not all USB controllers and target devices are compatible with this configuration. For instance, most PCs have a host-only USB controller, and the Raspberry Pi Model B is not compatible with gadgets because it contains an embedded USB hub upstream of the USB ports. (However, the Pi Zero is fully compatible with gadgets.)
I have a user space program that simulates a PCI device. I have downloaded the nvme linux device driver that interacts with the PCI device using the NVMe standard. I have to verify that my userspace program is compatible with the standard.
The nvme.c(the linux device driver) contains the nvme_probe() function that would be called when the device is plugged in. Since I do not have the device so I think I will incorporate the probe functionality in nvme_init() function.
Now I have studied quite a lot on the internet to understand how to emulate a PCI device, posts such as
Installing PCI driver without connection to device,
emulating a PCI device on linux
I do not get the idea how to return the populated struct pci_dev to the function call in the nvme_probe() ofpci_set_drvdata(pdev, dev);
And if you could suggest a tutorial, on how to manually populate the pci_dev struct with dummy device configuration and memory address of the userspace program function pointers to emulate interaction with the nvme driver.
I don't think it is possible to fake such thing with standard linux kernel.
Because in module_init() you are telling the kernel's PCI SUBSYSTEM to load the operation handlers (a.k.a - callbacks through function pointers) when a certain device is present in the system (via id_table).
so whenever you insmod your module, kernel's PCI SUBSYTEM then knows to load your driver whenever a device of matching vid/pid is plugged into the PCIe slot. The operation is like below -
Tell kernel to load {my_driver.ko} when this {vid/pid} pci device is
found in module_init or _init
After kernel knew, whenever a matching {vid/pid} device is connected to the system, it will call the .probe function callback of {my_driver.ko}
You may init the device (for real-device) or just return true to tell kernel that has correctly initialized the device.
You can also register new driver type from this probe function (for
read/write).
I am not sure about any magic VID/PID number which causes the PCI SUBSYTEM to always load the driver.
But you can actually load the PCI driver by using an actual PCI device.
Just remove appropriate driver for a real-PCI device. and use it's VID & PID as your driver's VID PID. Then the PCI SUBSYTEM will load your driver & you can also test your driver to simulate PCI device afterwards.
Hope this helps,
regards.