b27e35f91c
Original driver code was using three gpio's for reset asserts and deasserts the pcis. Instead of using that a general reset control with a perst gpio was introduced and it seems it is partially working but sometimes there are some unexpected hangs on boot. This commit make use of the three original gpios using 'reset-gpios' property of the device tree and removes the reset line and perst gpio. According to the mediatek aplication note v0.1 there are three gpios used for pcie ports reset control: gpio#19, gpio#8 and gpio#7 for slots 0, 1 and 2 respectively. This schema can be used separately for mt7621A but in some boards due to pin share issue, if the PCM and I2S function are enable at the same time, there are no enough GPIO to control per-port PCIe reset. In those cases gpio#19 is enought for reset the three ports together. Because of this we just try to get the three gpios but if some of them fail we are not failing in boot process, just prints a kernel notice and take after into account if the descriptor is or not valid in order to use it. All of them are set as GPIO output low configuration. The gpio descriptor's API takes device tree property into account and invert value if the pin is configured as active low. So we also have to properly request pins from device tree and set values correct in assert and deassert functions. After this changes the order to make all assert and deassert in the 'probe' process makes more sense: * Parse device tree. * make assert of the RC's and EP's before doing anything else. * make deassert of the RC's before initializing the phy. * Init the phy. * make deassert of the EP's before initialize pci ports. * Normal PCI initialization. Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com> Link: https://lore.kernel.org/r/20200313200913.24321-2-sergio.paracuellos@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.
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.