i2c: i2c-mlxbf: I2C SMBus driver for Mellanox BlueField SoC

Add BlueField I2C driver to offer master and slave support for
Mellanox BlueField SoCs. The driver implements an SMBus adapter
and interfaces to multiple busses that can be probed using both
ACPI and Device Tree infrastructures.

The driver supports several SMBus operations to transfer data
back and forth from/to various I2C devices. It is mainly intended
to be consumed by userspace tools and utilities, such as i2c-tools
and decode-dimms to collect memory module information.

On the other hand, the driver has a slave function to support,
among others, an IPMB interface that requires both master and
slave functions to handle transfers between the BlueField SoC
and a board management controllers (e.g., BMC).

Signed-off-by: Khalil Blaiech <kblaiech@mellanox.com>
Reviewed-by: Vadim Pasternak <vadimp@mellanox.com>

MAINTAINERS

@@ -11096,6 +11096,12 @@ W:	http://www.melfas.com
 F:	Documentation/devicetree/bindings/input/touchscreen/melfas_mip4.txt
 F:	drivers/input/touchscreen/melfas_mip4.c
 
+MELLANOX BLUEFIELD I2C DRIVER
+M:	Khalil Blaiech <kblaiech@mellanox.com>
+L:	linux-i2c@vger.kernel.org
+S:	Supported
+F:	drivers/i2c/busses/i2c-mlxbf.c
+
 MELLANOX ETHERNET DRIVER (mlx4_en)
 M:	Tariq Toukan <tariqt@nvidia.com>
 L:	netdev@vger.kernel.org

drivers/i2c/busses/Kconfig

@@ -730,6 +730,19 @@ config I2C_LPC2K
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-lpc2k.
 
+config I2C_MLXBF
+        tristate "Mellanox BlueField I2C controller"
+        depends on ARM64
+        help
+          Enabling this option will add I2C SMBus support for Mellanox BlueField
+          system.
+
+          This driver can also be built as a module. If so, the module will be
+          called i2c-mlxbf.
+
+          This driver implements an I2C SMBus host controller and enables both
+          master and slave functions.
+
 config I2C_MESON
 	tristate "Amlogic Meson I2C controller"
 	depends on ARCH_MESON || COMPILE_TEST

drivers/i2c/busses/Makefile

@@ -140,6 +140,7 @@ obj-$(CONFIG_I2C_BRCMSTB)	+= i2c-brcmstb.o
 obj-$(CONFIG_I2C_CROS_EC_TUNNEL)	+= i2c-cros-ec-tunnel.o
 obj-$(CONFIG_I2C_ELEKTOR)	+= i2c-elektor.o
 obj-$(CONFIG_I2C_ICY)		+= i2c-icy.o
+obj-$(CONFIG_I2C_MLXBF)		+= i2c-mlxbf.o
 obj-$(CONFIG_I2C_MLXCPLD)	+= i2c-mlxcpld.o
 obj-$(CONFIG_I2C_OPAL)		+= i2c-opal.o
 obj-$(CONFIG_I2C_PCA_ISA)	+= i2c-pca-isa.o