Hi All, I was as beginner in linux device driver development, and recently I was working on a device driver for espi protocol and was stuck with a problem. I have an mtd device driver through which one could access the NOR flash connected to the other end of espi bus. The driver seems to have probed successfully , I see an entry for my mtd device in /proc/mtd but , I dont see an entry for my mtd device in the /sys/class/mtd. Here are few logs of interest : root@mybox:~# cat /proc/mtd dev: size erasesize name mtd0: 04000000 00001000 "aspeed-espi-flash” <<<<<—— This is my mtd device mtd1: 04000000 00010000 "bmc" mtd2: 000e0000 00010000 "u-boot" mtd3: 00020000 00010000 "u-boot-env" mtd4: 00900000 00010000 "kernel" mtd5: 02000000 00010000 "rofs" mtd6: 01600000 00010000 "rwfs" mtd7: 04000000 00010000 "alt-bmc" mtd8: 000e0000 00010000 "alt-u-boot" mtd9: 00020000 00010000 "alt-u-boot-env" mtd10: 00900000 00010000 "alt-kernel" mtd11: 02000000 00010000 "alt-rofs" mtd12: 01600000 00010000 "alt-rwfs” root@mybox:/sys/class/mtd# ls mtd1 mtd10ro mtd11ro mtd12ro mtd2 mtd3 mtd4 mtd5 mtd6 mtd7 mtd8 mtd9 mtd10 mtd11 mtd12 mtd1ro mtd2ro mtd3ro mtd4ro mtd5ro mtd6ro mtd7ro mtd8ro mtd9ro I was expecting mtd0 to be present in the /sys/class/mtd, but its not there. Looking at dmesg: root@mybox:/sys/class/mtd# dmesg | grep -ie mtd -A5 -ie espi [ 0.685006] Entered the aspeed_espi_ctrl_probe function [ 0.690990] device matched : 1 [ 0.699225] espi alloc started [ 0.704726] espi read from device tree, flash size : 67108864 [ 0.712416] espi flash enabled [ 0.716572] espi flash channel is ready [ 0.720940] espi flash allocation completed [ 0.725259] aspeed-espi-ctrl 1e6ee000.espi-ctrl: module loaded -- [ 0.962764] 5 fixed-partitions partitions found on MTD device bmc [ 0.969675] Creating 5 MTD partitions on "bmc": [ 0.974776] 0x000000000000-0x0000000e0000 : "u-boot" [ 0.981982] 0x0000000e0000-0x000000100000 : "u-boot-env" [ 0.989557] 0x000000100000-0x000000a00000 : "kernel" [ 0.996772] 0x000000a00000-0x000002a00000 : "rofs" [ 1.003759] 0x000002a00000-0x000004000000 : "rwfs" -- [ 1.048304] 5 fixed-partitions partitions found on MTD device alt-bmc [ 1.055563] Creating 5 MTD partitions on "alt-bmc": [ 1.061096] 0x000000000000-0x0000000e0000 : "alt-u-boot" [ 1.068672] 0x0000000e0000-0x000000100000 : "alt-u-boot-env" [ 1.076607] 0x000000100000-0x000000a00000 : "alt-kernel" [ 1.084211] 0x000000a00000-0x000002a00000 : "alt-rofs" [ 1.091594] 0x000002a00000-0x000004000000 : "alt-rwfs” and the mtd devices listed in /sys/class/mtd from mtd1 through mtd12 are basically from the partitions list above. root@mybox:/sys/class/mtd# for dir in *; do cat $dir/name; done bmc alt-kernel alt-rofs alt-rwfs u-boot u-boot-env kernel rofs rwfs alt-bmc alt-u-boot alt-u-boot-env Does anyone know what could be the possible reason for the problem ? Any hints/help would be appreciated. Thanks, Manoj