Linux backport patch. Includes following commits:
e3448e71adb1fdd7f403c568ef5c2ed5adf2b197
c3bb77620da428884807fb2f6f3485644e146f84
db5f807ee3dcc779b78f59982cc3e89863069e9c


diff -Nur a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
--- a/drivers/i2c/muxes/Kconfig	2017-11-12 08:13:59.176044126 +0000
+++ b/drivers/i2c/muxes/Kconfig	2017-11-12 08:14:27.992044509 +0000
@@ -82,4 +82,15 @@
 	  demultiplexer that uses the pinctrl subsystem. This is useful if you
 	  want to change the I2C master at run-time depending on features.
 
+config I2C_MUX_MLXCPLD
+        tristate "Mellanox CPLD based I2C multiplexer"
+        help
+          If you say yes to this option, support will be included for a
+          CPLD based I2C multiplexer. This driver provides access to
+          I2C busses connected through a MUX, which is controlled
+          by a CPLD register.
+
+          This driver can also be built as a module.  If so, the module
+          will be called i2c-mux-mlxcpld.
+
 endmenu
diff -Nur a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
--- a/drivers/i2c/muxes/Makefile	2017-11-12 08:13:59.176044126 +0000
+++ b/drivers/i2c/muxes/Makefile	2017-11-12 08:14:27.992044509 +0000
@@ -6,6 +6,7 @@
 obj-$(CONFIG_I2C_DEMUX_PINCTRL)		+= i2c-demux-pinctrl.o
 
 obj-$(CONFIG_I2C_MUX_GPIO)	+= i2c-mux-gpio.o
+obj-$(CONFIG_I2C_MUX_MLXCPLD)	+= i2c-mux-mlxcpld.o
 obj-$(CONFIG_I2C_MUX_PCA9541)	+= i2c-mux-pca9541.o
 obj-$(CONFIG_I2C_MUX_PCA954x)	+= i2c-mux-pca954x.o
 obj-$(CONFIG_I2C_MUX_PINCTRL)	+= i2c-mux-pinctrl.o
diff -Nur a/drivers/i2c/muxes/i2c-mux-mlxcpld.c b/drivers/i2c/muxes/i2c-mux-mlxcpld.c
--- a/drivers/i2c/muxes/i2c-mux-mlxcpld.c	1970-01-01 00:00:00.000000000 +0000
+++ b/drivers/i2c/muxes/i2c-mux-mlxcpld.c	2017-11-12 08:14:27.992044509 +0000
@@ -0,0 +1,221 @@
+/*
+ * drivers/i2c/muxes/i2c-mux-mlxcpld.c
+ * Copyright (c) 2016 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2016 Michael Shych <michaels@mellanox.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/i2c-mux.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/i2c/mlxcpld.h>
+
+#define CPLD_MUX_MAX_NCHANS	8
+
+/* mlxcpld_mux - mux control structure:
+ * @last_chan - last register value
+ * @client - I2C device client
+ */
+struct mlxcpld_mux {
+	u8 last_chan;
+	struct i2c_client *client;
+};
+
+/* MUX logic description.
+ * Driver can support different mux control logic, according to CPLD
+ * implementation.
+ *
+ * Connectivity schema.
+ *
+ * i2c-mlxcpld                                 Digital               Analog
+ * driver
+ * *--------*                                 * -> mux1 (virt bus2) -> mux -> |
+ * | I2CLPC | i2c physical                    * -> mux2 (virt bus3) -> mux -> |
+ * | bridge | bus 1                 *---------*                               |
+ * | logic  |---------------------> * mux reg *                               |
+ * | in CPLD|                       *---------*                               |
+ * *--------*   i2c-mux-mlxpcld          ^    * -> muxn (virt busn) -> mux -> |
+ *     |        driver                   |                                    |
+ *     |        *---------------*        |                              Devices
+ *     |        * CPLD (i2c bus)* select |
+ *     |        * registers for *--------*
+ *     |        * mux selection * deselect
+ *     |        *---------------*
+ *     |                 |
+ * <-------->     <----------->
+ * i2c cntrl      Board cntrl reg
+ * reg space      space (mux select,
+ *                IO, LED, WD, info)
+ *
+ */
+
+static const struct i2c_device_id mlxcpld_mux_id[] = {
+	{ "mlxcpld_mux_module", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, mlxcpld_mux_id);
+
+/* Write to mux register. Don't use i2c_transfer() and i2c_smbus_xfer()
+ * for this as they will try to lock adapter a second time.
+ */
+static int mlxcpld_mux_reg_write(struct i2c_adapter *adap,
+				 struct i2c_client *client, u8 val)
+{
+	struct mlxcpld_mux_plat_data *pdata = dev_get_platdata(&client->dev);
+	int ret = -ENODEV;
+
+	if (adap->algo->master_xfer) {
+		struct i2c_msg msg;
+		u8 msgbuf[] = {pdata->sel_reg_addr, val};
+
+		msg.addr = client->addr;
+		msg.flags = 0;
+		msg.len = 2;
+		msg.buf = msgbuf;
+		ret = __i2c_transfer(adap, &msg, 1);
+
+		if (ret >= 0 && ret != 1)
+			ret = -EREMOTEIO;
+	} else if (adap->algo->smbus_xfer) {
+		union i2c_smbus_data data;
+
+		data.byte = val;
+		ret = adap->algo->smbus_xfer(adap, client->addr,
+					     client->flags, I2C_SMBUS_WRITE,
+					     pdata->sel_reg_addr,
+					     I2C_SMBUS_BYTE_DATA, &data);
+	}
+
+	return ret;
+}
+
+static int mlxcpld_mux_select_chan(struct i2c_mux_core *muxc, u32 chan)
+{
+	struct mlxcpld_mux *data = i2c_mux_priv(muxc);
+	struct i2c_client *client = data->client;
+	u8 regval = chan + 1;
+	int err = 0;
+
+	/* Only select the channel if its different from the last channel */
+	if (data->last_chan != regval) {
+		err = mlxcpld_mux_reg_write(muxc->parent, client, regval);
+		data->last_chan = err < 0 ? 0 : regval;
+	}
+
+	return err;
+}
+
+static int mlxcpld_mux_deselect(struct i2c_mux_core *muxc, u32 chan)
+{
+	struct mlxcpld_mux *data = i2c_mux_priv(muxc);
+	struct i2c_client *client = data->client;
+
+	/* Deselect active channel */
+	data->last_chan = 0;
+
+	return mlxcpld_mux_reg_write(muxc->parent, client, data->last_chan);
+}
+
+/* Probe/reomove functions */
+static int mlxcpld_mux_probe(struct i2c_client *client,
+			     const struct i2c_device_id *id)
+{
+	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
+	struct mlxcpld_mux_plat_data *pdata = dev_get_platdata(&client->dev);
+	struct i2c_mux_core *muxc;
+	int num, force;
+	struct mlxcpld_mux *data;
+	int err;
+
+	if (!pdata)
+		return -EINVAL;
+
+	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
+		return -ENODEV;
+
+	muxc = i2c_mux_alloc(adap, &client->dev, CPLD_MUX_MAX_NCHANS,
+			     sizeof(*data), 0, mlxcpld_mux_select_chan,
+			     mlxcpld_mux_deselect);
+	if (!muxc)
+		return -ENOMEM;
+
+	data = i2c_mux_priv(muxc);
+	i2c_set_clientdata(client, muxc);
+	data->client = client;
+	data->last_chan = 0; /* force the first selection */
+
+	/* Create an adapter for each channel. */
+	for (num = 0; num < CPLD_MUX_MAX_NCHANS; num++) {
+		if (num >= pdata->num_adaps)
+			/* discard unconfigured channels */
+			break;
+
+		force = pdata->adap_ids[num];
+
+		err = i2c_mux_add_adapter(muxc, force, num, 0);
+		if (err)
+			goto virt_reg_failed;
+	}
+
+	return 0;
+
+virt_reg_failed:
+	i2c_mux_del_adapters(muxc);
+	return err;
+}
+
+static int mlxcpld_mux_remove(struct i2c_client *client)
+{
+	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
+
+	i2c_mux_del_adapters(muxc);
+	return 0;
+}
+
+static struct i2c_driver mlxcpld_mux_driver = {
+	.driver		= {
+		.name	= "mlxcpld-mux",
+	},
+	.probe		= mlxcpld_mux_probe,
+	.remove		= mlxcpld_mux_remove,
+	.id_table	= mlxcpld_mux_id,
+};
+
+module_i2c_driver(mlxcpld_mux_driver);
+
+MODULE_AUTHOR("Michael Shych (michaels@mellanox.com)");
+MODULE_DESCRIPTION("Mellanox I2C-CPLD-MUX driver");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("platform:i2c-mux-mlxcpld");
diff -Nur a/include/linux/i2c/mlxcpld.h b/include/linux/i2c/mlxcpld.h
--- a/include/linux/i2c/mlxcpld.h	1970-01-01 00:00:00.000000000 +0000
+++ b/include/linux/i2c/mlxcpld.h	2017-11-12 08:17:03.032046568 +0000
@@ -0,0 +1,52 @@
+/*
+ * mlxcpld.h - Mellanox I2C multiplexer support in CPLD
+ *
+ * Copyright (c) 2016 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2016 Michael Shych <michaels@mellanox.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _LINUX_I2C_MLXCPLD_H
+#define _LINUX_I2C_MLXCPLD_H
+
+/* Platform data for the CPLD I2C multiplexers */
+
+/* mlxcpld_mux_plat_data - per mux data, used with i2c_register_board_info
+ * @adap_ids - adapter array
+ * @num_adaps - number of adapters
+ * @sel_reg_addr - mux select register offset in CPLD space
+ */
+struct mlxcpld_mux_plat_data {
+	int *adap_ids;
+	int num_adaps;
+	int sel_reg_addr;
+};
+
+#endif /* _LINUX_I2C_MLXCPLD_H */
