Timur Tabi authored Apr 25, 2018 and Linus Walleij committed May 02, 2018

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>