> >> mfd_add_devices() is called, it uses &dev->resource as the base. So the BAR will > >> be the parent. Check the code in mfd-core.c, mfd_add_device(), > >> > >> if ((cell->resources[r].flags & IORESOURCE_MEM) && mem_base) { > >> res[r].parent = mem_base; > >> res[r].start = mem_base->start + cell->resources[r].start; > >> res[r].end = mem_base->start + cell->resources[r].end; > >> } > >> > >> So the MFD resource is within its parent. When later the device driver request a > >> region, will it get conflict with the parent? > > > > I doubt you'll want to map the same memory area in both the parent and > > the child device drivers. Only map the registers you plan to use in > > the driver you plan to use them. If you need multiple devices to > > access the same registers then you need to create an API, complete > > with locking, in the MFD parent device. > > Thanks for pointing out. I thought at first the conflict was due to my > pci_ioremap_bar(). I went ahead to remove the mapping but still not working. > Your email inspired me to take a deeper look at my code and I found my error. I > have called pci_request_regions() which reserves all BARs. I think that's my > root cause. Thanks for helping me. You are welcome. -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html