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2ddc982a6c
Currently iio_debugfs_read_reg calls debugfs_reg_access
every time it is ran. Reading the same hardware register
multiple times during the same reading of a debugfs file
can cause unintended effects.
For example for each: cat iio:device0/direct_reg_access
the file_operations.read function will be called at least
twice. First will return the full length of the string in
bytes and the second will return 0.
This patch makes iio_debugfs_read_reg to call debugfs_reg_access
only when the user's buffer position (*ppos) is 0. (meaning
it is the beginning of a new reading of the debugfs file).
Fixes: e553f182d5 ("staging: iio: core: Introduce debugfs support, add support for direct register access")
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.