I’ve gone through it and I’m planning to learn PCIe Card Reader. There I’ve understood that /drivers/misc/cardreader/rtsx_pci.ko (while rtsx_pci.ko = rtsx_pcr.o rts5209.o rts5229.o rtl8411.o rts5227.o rts5249.o rts5260.o rts5261.o rts5228.o) is the PCIe Card Reader Hardware that is available in Laptop and /drivers/mmc/host/rtsx_pci_sdmmc.ko is the MMC card interface via PCIe Card Reader.

In that rtsx_pci.ko has used module_pci_driver, while rtsx_pci_sdmmc.ko uses module_platform_driver. Why is that so? What does it mean by Platform device driver? Why haven’t they used pci_register_driver directly?

Kindly to clarify the doubt sir. I was unable to find answers anywhere.

I’m porting a pcie device driver and it used to call of_node_full_name() in the probe function. I need to read the device tree but every attempt to read has failed.

Something like this:

static int probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
pr_info(“Found PCI device: %s\n”, of_node_full_name(pdev->dev.of_node));
}

Could you include some example how to?

Thank you.

You’re welcome 🙂

When I used this as a template I found that the MSI free routine at unload would seg fault.

I debugged this down to two things… you should use pci_irq_vector() to get the actual assigned IRQ vector to assign to the handler.

retval = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_MSI);
irq = pci_irq_vector(dev, 0);
retval = request_irq(irq, irq_fnc, 0, “name”, dev);

and number two you need to free the IRQ before deallocating from the PCI layer.
release_device()
…
irq = pci_irq_vector(dev,0);
free_irq(irq, pdev);
pci_free_irq_vectors(pdev);

Again thanks for documenting this SUPER helpful.

This function is called on character device read.
For example cat /dev/mydriver will open your character device and call ‘read’ function. In the case of my driver, lirdev_read is called.

Thanks

Sure. It’s Linux device drivers 3rd edition book,
Linux kernel PCI documentation: https://www.kernel.org/doc/html/latest/PCI/pci.html
And existing PCI device drivers, just as an example.