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OpenCloudOS-Kernel/Documentation/ABI/stable/sysfs-bus-nvmem

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Documentation/ABI: document the nvmem sysfs files NVMEM has been in kernel since v4.2 but the ABI document was missing since then. userspace interface did not change since then and seems stable, so this patch documents the nvmem ABI. Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-26 18:09:02 +08:00
What: /sys/bus/nvmem/devices/.../nvmem
Date: July 2015
KernelVersion: 4.2
Contact: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Description:
This file allows user to read/write the raw NVMEM contents.
Permissions for write to this file depends on the nvmem
provider configuration.
nvmem: core: add NVMEM_SYSFS Kconfig Many nvmem providers are not very keen on having default sysfs nvmem entry, as most of the usecases for them are inside kernel itself. And in some cases read/writes to some areas in nvmem are restricted and trapped at secure monitor level, so accessing them from userspace would result in board reboots. This patch adds new NVMEM_SYSFS Kconfig to make binary sysfs entry an optional one. This provision will give more flexibility to users. This patch also moves existing sysfs code to a new file so that its not compiled in when its not really required. Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Gaurav Kohli <gkohli@codeaurora.org> Tested-by: Gaurav Kohli <gkohli@codeaurora.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-16 17:59:24 +08:00
Note: This file is only present if CONFIG_NVMEM_SYSFS
is enabled
Documentation/ABI: document the nvmem sysfs files NVMEM has been in kernel since v4.2 but the ABI document was missing since then. userspace interface did not change since then and seems stable, so this patch documents the nvmem ABI. Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-26 18:09:02 +08:00
ex:
hexdump /sys/bus/nvmem/devices/qfprom0/nvmem
0000000 0000 0000 0000 0000 0000 0000 0000 0000
*
00000a0 db10 2240 0000 e000 0c00 0c00 0000 0c00
0000000 0000 0000 0000 0000 0000 0000 0000 0000
...
*
0001000