Julia and other experts, I am seeking for help on my device driver. I am working on a module driver for a FPGA design with open core I2C controller memory-mapped to BAR2. I have searched up and down and found only one driver (drivers/mfd/timberdale.c) with similar implementation. Following timberdale driver, I am able to load the driver, but blocked by devm_ioremap_resource(). It is always in conflict with my BAR2. I wonder if I did something wrong. Here is the flow I tracked so far. (By the way, I am using an older kernel 3.12. The new 4.0 kernel crashes when booting on my platform. I plan to move to newer kernel later). mfd_add_devices() | |--mfd_add_device() | |--platform_device_add() | |--insert_resource() /* this passed */ | | | |--insert_resource_conflict() | |--device_add() | |--bus_probe_device() | |--devm_ioremap_resource() | |--devm_request_mem_region() | |--__request_region() /* this always conflicts */ | |--__request_resource() My driver is called RedStone DMA. Here is my debug output > root@p1022ds:~# insmod redstone_mfd.ko > RedStone DMA 0002:05:00.0: pci_enable_device() successful > RedStone DMA 0002:05:00.0: MSI-X init successful > York kernel: Calling devm_ioremap_resource() > York kernel kernel/resource.c __request_region 977: conflict=[??? 0xc00080000-0xc00087fff flags 0x80000000] > ocores-i2c ocores-i2c: can't request region for resource [mem 0xc00086000-0xc0008601f] > ocores-i2c: probe of ocores-i2c failed with error -16 > RedStone DMA 0002:05:00.0: BAR[0] 0x0000000c00000000-0x0000000c0007ffff flags 0x0014220c, length 524288 > RedStone DMA 0002:05:00.0: BAR[1] 0x0000000000000000-0x0000000000000000 flags 0x00000000, length 0 > RedStone DMA 0002:05:00.0: BAR[2] 0x0000000c00080000-0x0000000c00087fff flags 0x00040200, length 32768 > RedStone DMA 0002:05:00.0: BAR[3] 0x0000000000000000-0x0000000000000000 flags 0x00000000, length 0 > RedStone DMA 0002:05:00.0: BAR[4] 0x0000000000000000-0x0000000000000000 flags 0x00000000, length 0 > RedStone DMA 0002:05:00.0: BAR[5] 0x0000000000000000-0x0000000000000000 flags 0x00000000, length 0 > RedStone DMA 0002:05:00.0: Version 1.4, built on 4-16-15, id 0 > root@p1022ds:~# Can you shed some light on this? Thanks. York -- 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