i2c: Add drivers for the AMD PCIe MP2 I2C controller

MP2 controllers have two separate busses, so may accommodate up to two I2C
adapters. Those adapters are listed in the ACPI namespace with the
"AMDI0011" HID, and probed by a platform driver.

Communication with the MP2 takes place through MMIO registers, or through
DMA for more than 32 bytes transfers.

This is major rework of the patch submitted by Nehal-bakulchandra Shah from
AMD (https://patchwork.kernel.org/patch/10597369/).

Most of the event handling of v3 was rewritten to make it work with more
than one bus (e.g on Ryzen-based Lenovo Yoga 530), and this version
contains many other improvements.

Signed-off-by: Elie Morisse <syniurge@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Author: Syniurge

Documentation/i2c/busses/i2c-amd-mp2

@@ -0,0 +1,23 @@
+Kernel driver i2c-amd-mp2
+
+Supported adapters:
+  * AMD MP2 PCIe interface
+
+Datasheet: not publicly available.
+
+Authors:
+	Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
+	Nehal Shah <nehal-bakulchandra.shah@amd.com>
+	Elie Morisse <syniurge@gmail.com>
+
+Description
+-----------
+
+The MP2 is an ARM processor programmed as an I2C controller and communicating
+with the x86 host through PCI.
+
+If you see something like this:
+
+03:00.7 MP2 I2C controller: Advanced Micro Devices, Inc. [AMD] Device 15e6
+
+in your 'lspci -v', then this driver is for your device.

MAINTAINERS

@@ -816,6 +816,14 @@ F:	drivers/gpu/drm/amd/include/vi_structs.h
 F:	drivers/gpu/drm/amd/include/v9_structs.h
 F:	include/uapi/linux/kfd_ioctl.h
 
+AMD MP2 I2C DRIVER
+M:	Elie Morisse <syniurge@gmail.com>
+M:	Nehal Shah <nehal-bakulchandra.shah@amd.com>
+M:	Shyam Sundar S K <shyam-sundar.s-k@amd.com>
+L:	linux-i2c@vger.kernel.org
+S:	Maintained
+F:	drivers/i2c/busses/i2c-amd-mp2*
+
 AMD POWERPLAY
 M:	Rex Zhu <rex.zhu@amd.com>
 M:	Evan Quan <evan.quan@amd.com>

drivers/i2c/busses/Kconfig

@@ -77,6 +77,16 @@ config I2C_AMD8111
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-amd8111.
 
+config I2C_AMD_MP2
+	tristate "AMD MP2 PCIe"
+	depends on PCI && ACPI
+	help
+	  If you say yes to this option, support will be included for the AMD
+	  MP2 PCIe I2C adapter.
+
+	  This driver can also be built as modules.  If so, the modules will
+	  be called i2c-amd-mp2-pci and i2c-amd-mp2-plat.
+
 config I2C_HIX5HD2
 	tristate "Hix5hd2 high-speed I2C driver"
 	depends on ARCH_HISI || ARCH_HIX5HD2 || COMPILE_TEST

drivers/i2c/busses/Makefile

@@ -33,6 +33,7 @@ obj-$(CONFIG_I2C_POWERMAC)	+= i2c-powermac.o
 
 # Embedded system I2C/SMBus host controller drivers
 obj-$(CONFIG_I2C_ALTERA)	+= i2c-altera.o
+obj-$(CONFIG_I2C_AMD_MP2)	+= i2c-amd-mp2-pci.o i2c-amd-mp2-plat.o
 obj-$(CONFIG_I2C_ASPEED)	+= i2c-aspeed.o
 obj-$(CONFIG_I2C_AT91)		+= i2c-at91.o
 i2c-at91-objs			:= i2c-at91-core.o i2c-at91-master.o