NVIDIA: SAUCE: MEDIATEK: pinctrl: mediatek: Add EINT Driver for CX7 hot plug on DGX Spark

This driver is used to manage PCIe link for NVIDIA ConnectX-7 (CX7)
hot-plug/unplug on DGX Spark. We need to disable PCIe link when
CX7 cable plug out happens and enable pcie link when
CX7 cable plug in happens.

It also creates a sysfs entry to emulate cable plug in/out
behavior as below:

plug in - echo 1 > /sys/devices/platform/MTKP0001:00/cx7_dbg/plugin
plug out - echo 0 > /sys/devices/platform/MTKP0001:00/cx7_dbg/plugin

We also implement uevent to notify user-space applications when a
cable is plugged in or removed. Below are the details of our process:

* cable plug-in:
    Report plug-in uevent (driver)
    Power on CX7
    Enable PCIe link (application)
    Rescan CX7 devices (application)

* cable removal:
    Report removal uevent (driver)
    Remove CX7 devices (application)
    Disable PCIe link (application)
    Power off CX7

Signed-off-by: Vaibhav Vyas <[email protected]>
Signed-off-by: Jerry.Guo <[email protected]>
Signed-off-by: Yenchia Chen <[email protected]>
Signed-off-by: Shubhi Garg <[email protected]>
Signed-off-by: Abhishek Sahu <[email protected]>
Signed-off-by: Surabhi Chythanya Kumar <[email protected]>

Author: schythanyaku

debian.nvidia-6.17/config/annotations

@@ -207,6 +207,7 @@ CONFIG_CC_HAS_SANE_FUNCTION_ALIGNMENT           policy<{'amd64': '-', 'arm64': '
 CONFIG_CC_VERSION_TEXT                          policy<{'amd64': '"x86_64-linux-gnu-gcc-13 (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0"', 'arm64': '"aarch64-linux-gnu-gcc-13 (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0"'}>
 CONFIG_CORESIGHT_CTCU                           policy<{'arm64': 'm'}>
 CONFIG_CPUFREQ_DT_RUST                          policy<{'arm64': '-'}>
+CONFIG_EINT_MTK_HP                              policy<{'arm64': 'm'}>
 CONFIG_DRM_NOUVEAU_CH7006                       policy<{'amd64': '-', 'arm64': '-'}>
 CONFIG_DRM_NOUVEAU_SIL164                       policy<{'amd64': '-', 'arm64': '-'}>
 CONFIG_DRM_NOVA                                 policy<{'amd64': '-', 'arm64': '-'}>

drivers/pinctrl/mediatek/Kconfig

@@ -10,6 +10,15 @@ config EINT_MTK
 	default y if PINCTRL_MTK || PINCTRL_MTK_MOORE
 	default PINCTRL_MTK_PARIS
 
+config EINT_MTK_HP
+	tristate "MediaTek HP Driver"
+	depends on EINT_MTK
+	help
+	  Say yes here to support NICs cable plug in/out test.
+	  It will disable pcie link when plug out and enable
+	  pcie link after plug in cable.
+	  This is particularly useful for MediaTek MT8901 SoC.
+
 config PINCTRL_MTK
 	bool
 	depends on OF

drivers/pinctrl/mediatek/Makefile

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 # Core
 obj-$(CONFIG_EINT_MTK)			+= mtk-eint.o
+obj-$(CONFIG_EINT_MTK_HP)		+= mtk-eint-hotplug.o
 obj-$(CONFIG_PINCTRL_MTK)		+= pinctrl-mtk-common.o
 obj-$(CONFIG_PINCTRL_MTK_V2)		+= pinctrl-mtk-common-v2.o
 obj-$(CONFIG_PINCTRL_MTK_MTMIPS)	+= pinctrl-mtmips.o