e20f378d - nvmem: include bit index in cell sysfs file name

Fri, 09 Feb 2024 16:34:54 +0000

nvmem: include bit index in cell sysfs file nameCreating sysfs files for all Cells caused a boot failure for linux-6.8-rc1 onApple M1, which (in downstream dts files) has multiple nvmem cells that use thesame byte address. This causes the device probe to fail with[ 0.605336] sysfs: cannot create duplicate filename '/devices/platform/soc@200000000/2922bc000.efuse/apple_efuses_nvmem0/cells/efuse@a10'[ 0.605347] CPU: 7 PID: 1 Comm: swapper/0 Tainted: G S 6.8.0-rc1-arnd-5+ #133[ 0.605355] Hardware name: Apple Mac Studio (M1 Ultra, 2022) (DT)[ 0.605362] Call trace:[ 0.605365] show_stack+0x18/0x2c[ 0.605374] dump_stack_lvl+0x60/0x80[ 0.605383] dump_stack+0x18/0x24[ 0.605388] sysfs_warn_dup+0x64/0x80[ 0.605395] sysfs_add_bin_file_mode_ns+0xb0/0xd4[ 0.605402] internal_create_group+0x268/0x404[ 0.605409] sysfs_create_groups+0x38/0x94[ 0.605415] devm_device_add_groups+0x50/0x94[ 0.605572] nvmem_populate_sysfs_cells+0x180/0x1b0[ 0.605682] nvmem_register+0x38c/0x470[ 0.605789] devm_nvmem_register+0x1c/0x6c[ 0.605895] apple_efuses_probe+0xe4/0x120[ 0.606000] platform_probe+0xa8/0xd0As far as I can tell, this is a problem for any device with multiple cells ondifferent bits of the same address. Avoid the issue by changing the file nameto include the first bit number.Fixes: 0331c611949f ("nvmem: core: Expose cells through sysfs")Link: https://github.com/AsahiLinux/linux/blob/bd0a1a7d4/arch/arm64/boot/dts/apple/t600x-dieX.dtsi#L156Cc: Cc: Miquel Raynal Cc: Rafał Miłecki Cc: Chen-Yu Tsai Cc: Srinivas Kandagatla Cc: Greg Kroah-Hartman Cc: Cc: Sven Peter Signed-off-by: Arnd Bergmann Signed-off-by: Srinivas Kandagatla Reviewed-by: Eric Curtin Reviewed-by: Miquel Raynal Link: https://lore.kernel.org/r/20240209163454.98051-1-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman List of files: /linux-6.15/Documentation/ABI/testing/sysfs-nvmem-cells

192048e5 - ABI: sysfs-nvmem-cells: Expose cells through sysfs

Fri, 15 Dec 2023 11:15:33 +0000

ABI: sysfs-nvmem-cells: Expose cells through sysfsThe binary content of nvmem devices is available to the user so in theeasiest cases, finding the content of a cell is rather easy as it isjust a matter of looking at a known and fixed offset. However, nvmemlayouts have been recently introduced to cope with more advancedsituations, where the offset and size of the cells is not known inadvance or is dynamic. When using layouts, more advanced parsers areused by the kernel in order to give direct access to the content of eachcell regardless of their position/size in the underlying device, butthese information were not accessible to the user.By exposing the nvmem cells to the user through a dedicated cell/ foldercontaining one file per cell, we provide a straightforward access touseful user information without the need for re-writing a userlandparser. Content of nvmem cells is usually: product names, manufacturingdate, MAC addresses, etc,Signed-off-by: Miquel Raynal Reviewed-by: Greg Kroah-Hartman Signed-off-by: Srinivas Kandagatla Link: https://lore.kernel.org/r/20231215111536.316972-8-srinivas.kandagatla@linaro.orgSigned-off-by: Greg Kroah-Hartman List of files: /linux-6.15/Documentation/ABI/testing/sysfs-nvmem-cells

Changes in sysfs-nvmem-cells

e20f378d - nvmem: include bit index in cell sysfs file name

192048e5 - ABI: sysfs-nvmem-cells: Expose cells through sysfs