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Commit86c92b9965("i2c: tegra: Add DMA support") added DMA support to the Tegra I2C driver for Tegra devices that support the APB DMA controller. One side-effect of this change is that even for Tegra devices that do not have an APB DMA controller and hence, cannot support DMA tranfers for I2C transactions, the following error messages are still displayed ... ERR KERN tegra-i2c 31c0000.i2c: cannot use DMA: -19 ERR KERN tegra-i2c 31c0000.i2c: falling back to PIO There is no point displaying the above messages for devices that do not have an APB DMA controller and so fix this by returning from the tegra_i2c_init_dma() function if 'has_apb_dma' is not true. Furthermore, if CONFIG_TEGRA20_APB_DMA is not set, then rather than printing an error message, print an debug message as for whatever reason this could be intentional. Fixes:86c92b9965("i2c: tegra: Add DMA support") Signed-off-by: Jonathan Hunter <jonathanh@nvidia.com> Reviewed-by: Dmitry Osipenko <digetx@gmail.com> Acked-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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.