nvmem_get_cell_len

Hello,

in /sys/dev/extres/nvmem/nvmem.c
nvmem_get_cell_len can’t properly return an error or a valid size
probably the size should be returned via a pointer to size_t arg and return 0 on success
the function does not seem to be used anywhere (13.2) so it should be easy to change

also why is it an error in nvmem_read_cell_by_idx if the buflen arg is larger than the actual cell size ? (the same is in aw_sid too)