diff --git a/MAINTAINERS b/MAINTAINERS
index 1869e83f514a44f6a16ab28204c263558ff4c624..a71ab252ad7ecdfa31ccd9f5725e381072a2fae5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1635,6 +1635,7 @@ F: Documentation/ABI/testing/sysfs-bus-moxtet-devices
F: Documentation/devicetree/bindings/bus/moxtet.txt
F: include/linux/moxtet.h
F: drivers/bus/moxtet.c
+F: drivers/gpio/gpio-moxtet.c
ARM/EBSA110 MACHINE SUPPORT
M: Russell King <linux@armlinux.org.uk>
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index bb13c266c32968be8bd0864ddd2cf00266d910e7..eef4886a3bc33c8f6e7e9c93fe057388452d2e8e 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -1445,6 +1445,15 @@ config GPIO_XRA1403
help
GPIO driver for EXAR XRA1403 16-bit SPI-based GPIO expander.
+config GPIO_MOXTET
+ tristate "Turris Mox Moxtet bus GPIO expander"
+ depends on MOXTET
+ help
+ Say yes here if you are building for the Turris Mox router.
+ This is the driver needed for configuring the GPIOs via the Moxtet
+ bus. For example the Mox module with SFP cage needs this driver
+ so that phylink can use corresponding GPIOs.
+
endmenu
menu "USB GPIO expanders"
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index a4e91175c70805508d2bfe90c567102264bb59ca..2e10caec23ae2db2664c18cb64272073cd7ef32e 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -93,6 +93,7 @@ obj-$(CONFIG_GPIO_ML_IOH) += gpio-ml-ioh.o
obj-$(CONFIG_GPIO_MLXBF) += gpio-mlxbf.o
obj-$(CONFIG_GPIO_MM_LANTIQ) += gpio-mm-lantiq.o
obj-$(CONFIG_GPIO_MOCKUP) += gpio-mockup.o
+obj-$(CONFIG_GPIO_MOXTET) += gpio-moxtet.o
obj-$(CONFIG_GPIO_MPC5200) += gpio-mpc5200.o
obj-$(CONFIG_GPIO_MPC8XXX) += gpio-mpc8xxx.o
obj-$(CONFIG_GPIO_MSIC) += gpio-msic.o
diff --git a/drivers/gpio/gpio-moxtet.c b/drivers/gpio/gpio-moxtet.c
new file mode 100644
index 0000000000000000000000000000000000000000..3fd729994a3878eb844a84a62180321f5cd441b1
--- /dev/null
+++ b/drivers/gpio/gpio-moxtet.c
@@ -0,0 +1,179 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Turris Mox Moxtet GPIO expander
+ *
+ * Copyright (C) 2018 Marek Behun <marek.behun@nic.cz>
+ */
+
+#include <linux/bitops.h>
+#include <linux/gpio/driver.h>
+#include <linux/moxtet.h>
+#include <linux/module.h>
+
+#define MOXTET_GPIO_NGPIOS 12
+#define MOXTET_GPIO_INPUTS 4
+
+struct moxtet_gpio_desc {
+ u16 in_mask;
+ u16 out_mask;
+};
+
+static const struct moxtet_gpio_desc descs[] = {
+ [TURRIS_MOX_MODULE_SFP] = {
+ .in_mask = GENMASK(2, 0),
+ .out_mask = GENMASK(5, 4),
+ },
+};
+
+struct moxtet_gpio_chip {
+ struct device *dev;
+ struct gpio_chip gpio_chip;
+ const struct moxtet_gpio_desc *desc;
+};
+
+static int moxtet_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
+{
+ struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
+ int ret;
+
+ if (chip->desc->in_mask & BIT(offset)) {
+ ret = moxtet_device_read(chip->dev);
+ } else if (chip->desc->out_mask & BIT(offset)) {
+ ret = moxtet_device_written(chip->dev);
+ if (ret >= 0)
+ ret <<= MOXTET_GPIO_INPUTS;
+ } else {
+ return -EINVAL;
+ }
+
+ if (ret < 0)
+ return ret;
+
+ return !!(ret & BIT(offset));
+}
+
+static void moxtet_gpio_set_value(struct gpio_chip *gc, unsigned int offset,
+ int val)
+{
+ struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
+ int state;
+
+ state = moxtet_device_written(chip->dev);
+ if (state < 0)
+ return;
+
+ offset -= MOXTET_GPIO_INPUTS;
+
+ if (val)
+ state |= BIT(offset);
+ else
+ state &= ~BIT(offset);
+
+ moxtet_device_write(chip->dev, state);
+}
+
+static int moxtet_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
+{
+ struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
+
+ /* All lines are hard wired to be either input or output, not both. */
+ if (chip->desc->in_mask & BIT(offset))
+ return 1;
+ else if (chip->desc->out_mask & BIT(offset))
+ return 0;
+ else
+ return -EINVAL;
+}
+
+static int moxtet_gpio_direction_input(struct gpio_chip *gc,
+ unsigned int offset)
+{
+ struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
+
+ if (chip->desc->in_mask & BIT(offset))
+ return 0;
+ else if (chip->desc->out_mask & BIT(offset))
+ return -ENOTSUPP;
+ else
+ return -EINVAL;
+}
+
+static int moxtet_gpio_direction_output(struct gpio_chip *gc,
+ unsigned int offset, int val)
+{
+ struct moxtet_gpio_chip *chip = gpiochip_get_data(gc);
+
+ if (chip->desc->out_mask & BIT(offset))
+ moxtet_gpio_set_value(gc, offset, val);
+ else if (chip->desc->in_mask & BIT(offset))
+ return -ENOTSUPP;
+ else
+ return -EINVAL;
+
+ return 0;
+}
+
+static int moxtet_gpio_probe(struct device *dev)
+{
+ struct moxtet_gpio_chip *chip;
+ struct device_node *nc = dev->of_node;
+ int id;
+
+ id = to_moxtet_device(dev)->id;
+
+ if (id >= ARRAY_SIZE(descs)) {
+ dev_err(dev, "%pOF Moxtet device id 0x%x is not supported by gpio-moxtet driver\n",
+ nc, id);
+ return -ENOTSUPP;
+ }
+
+ chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ chip->dev = dev;
+ chip->gpio_chip.parent = dev;
+ chip->desc = &descs[id];
+
+ dev_set_drvdata(dev, chip);
+
+ chip->gpio_chip.label = dev_name(dev);
+ chip->gpio_chip.get_direction = moxtet_gpio_get_direction;
+ chip->gpio_chip.direction_input = moxtet_gpio_direction_input;
+ chip->gpio_chip.direction_output = moxtet_gpio_direction_output;
+ chip->gpio_chip.get = moxtet_gpio_get_value;
+ chip->gpio_chip.set = moxtet_gpio_set_value;
+ chip->gpio_chip.base = -1;
+
+ chip->gpio_chip.ngpio = MOXTET_GPIO_NGPIOS;
+
+ chip->gpio_chip.can_sleep = true;
+ chip->gpio_chip.owner = THIS_MODULE;
+
+ return devm_gpiochip_add_data(dev, &chip->gpio_chip, chip);
+}
+
+static const struct of_device_id moxtet_gpio_dt_ids[] = {
+ { .compatible = "cznic,moxtet-gpio", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, moxtet_gpio_dt_ids);
+
+static const enum turris_mox_module_id moxtet_gpio_module_table[] = {
+ TURRIS_MOX_MODULE_SFP,
+ 0,
+};
+
+static struct moxtet_driver moxtet_gpio_driver = {
+ .driver = {
+ .name = "moxtet-gpio",
+ .of_match_table = moxtet_gpio_dt_ids,
+ .probe = moxtet_gpio_probe,
+ },
+ .id_table = moxtet_gpio_module_table,
+};
+module_moxtet_driver(moxtet_gpio_driver);
+
+MODULE_AUTHOR("Marek Behun <marek.behun@nic.cz>");
+MODULE_DESCRIPTION("Turris Mox Moxtet GPIO expander");
+MODULE_LICENSE("GPL v2");