phy: lantiq: vrx200-pcie: add a driver for the Lantiq VRX200 PCIe PHY

The Lantiq VRX200 SoCs embed a PCIe PHY in the "sram" bus. Unlike most
other IP blocks on this SoC the register values are only 16-bit wide.
Like other IP blocks on this SoC the register values are in big endian.

The PHY embeds a PLL which can be configured in various modes. Only the
36MHz mode is supported for now, the other modes can be implemented when
there's a board which actually needs them. OpenWrt uses the out-of-tree
vendor driver and all supported boards there only need the 36MHz mode.

There are two input clocks:
- the "pdi" clock enables the register access
- the "phy" clock is the clock input and enables the internal PLL

There are two reset lines:
- "phy" resets the PHY itself
- the "pcie" reset line is shared between the PHY and the PCIe
controller

While the VRX200 SoC has only one PCIe controller and PHY the ARX300
uses two identical PCIe controllers and PHYs which are compatible with
the PCIe controller and PHY on VRX200.
Add a driver for this PHY so PCIe support can be enabled on these SoCs.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

treewide: Add SPDX license identifier - Makefile/Kconfig

Add SPDX license identifiers to all Make/Kconfig files which:

- Have no license information of any form

These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:

GPL-2.0-only

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

phy: Add an USB PHY driver for the Lantiq SoCs using the RCU module

This driver starts the DWC2 core(s) built into the XWAY SoCs and provides
the PHY interfaces for each core. The phy instances can be passed to the
dwc2 driver, which already supports the generic phy interface.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Rob Herring <robh@kernel.org>
Cc: martin.blumenstingl@googlemail.com
Cc: john@phrozen.org
Cc: andy.shevchenko@gmail.com
Cc: p.zabel@pengutronix.de
Cc: mark.rutland@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-mtd@lists.infradead.org
Cc: linux-watchdog@vger.kernel.org
Cc: devicetree@vger.kernel.org
Cc: linux-spi@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17127/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>