Newer versions of the firmware for the Qualcomm Datacenter Technologies QDF2400 restricts access to a subset of the GPIOs on the TLMM. To prevent older kernels from accidentally accessing the restricted GPIOs, we change the ACPI HID for the TLMM block from QCOM8001 to QCOM8002, and introduce a new property "gpios". This property is an array of specific GPIOs that are accessible. When an older kernel boots on newer (restricted) firmware, it will fail to probe. To implement the sparse GPIO map, we register all of the GPIOs, but fill in the data only for available GPIOs. This ensures that the driver cannot accidentally access an unavailable GPIO. The pinctrl-msm driver also scans the "gpios" property to determine which pins are available, and ensure that only those can be registered. Support for QCOM8001 is removed as there is no longer any firmware that implements it. Signed-off-by: Timur Tabi <timur@codeaurora.org> Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org> Reviewed-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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. See Documentation/00-INDEX for a list of what is contained in each file. 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.
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