[PATCH 06/16] usb: typec: add FUSB340 SuperSpeed switch driver

[Fabrice Gasnier]

Add a platform driver for the ON Semiconductor FUSB340 SuperSpeed switch.
The driver uses enable-gpios and select-gpios to control the switch and
registers Type-C switch and mux providers for Type-C applications where a
reversible cable requires a switch.

Assisted-by: GitHub-Copilot:GPT-5.4-mini
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>
---
 drivers/usb/typec/mux/Kconfig   |   8 ++
 drivers/usb/typec/mux/Makefile  |   1 +
 drivers/usb/typec/mux/fusb340.c | 169 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 178 insertions(+)

diff --git a/drivers/usb/typec/mux/Kconfig b/drivers/usb/typec/mux/Kconfig
index 6dd8f961b593..6a1da48a2a8f 100644
--- a/drivers/usb/typec/mux/Kconfig
+++ b/drivers/usb/typec/mux/Kconfig
@@ -12,6 +12,14 @@ config TYPEC_MUX_FSA4480
 	  common USB Type-C connector.
 	  If compiled as a module, the module will be named fsa4480.
 
+config TYPEC_MUX_FUSB340
+	tristate "ON Semi FUSB340 SuperSpeed switch driver"
+	help
+	  Driver for the ON Semiconductor FUSB340 SuperSpeed switch, which
+	  provides support for routing SuperSpeed pairs in Type-C applications
+	  where a reversible cable requires a switch.
+	  If compiled as a module, the module will be named fusb340.
+
 config TYPEC_MUX_GPIO_SBU
 	tristate "Generic GPIO based SBU mux for USB Type-C applications"
 	help
diff --git a/drivers/usb/typec/mux/Makefile b/drivers/usb/typec/mux/Makefile
index b4f599eb5053..ef8d2b05ff7f 100644
--- a/drivers/usb/typec/mux/Makefile
+++ b/drivers/usb/typec/mux/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 obj-$(CONFIG_TYPEC_MUX_FSA4480)		+= fsa4480.o
+obj-$(CONFIG_TYPEC_MUX_FUSB340)		+= fusb340.o
 obj-$(CONFIG_TYPEC_MUX_GPIO_SBU)	+= gpio-sbu-mux.o
 obj-$(CONFIG_TYPEC_MUX_PI3USB30532)	+= pi3usb30532.o
 obj-$(CONFIG_TYPEC_MUX_INTEL_PMC)	+= intel_pmc_mux.o
diff --git a/drivers/usb/typec/mux/fusb340.c b/drivers/usb/typec/mux/fusb340.c
new file mode 100644
index 000000000000..0f0e45743784
--- /dev/null
+++ b/drivers/usb/typec/mux/fusb340.c
@@ -0,0 +1,169 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ON Semiconductor FUSB340 SuperSpeed switch driver
+ *
+ * Copyright (C) 2026 STMicroelectronics
+ */
+
+#include <linux/device.h>
+#include <linux/gpio/consumer.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/usb/typec_altmode.h>
+#include <linux/usb/typec_mux.h>
+
+struct fusb340 {
+	struct gpio_desc *enable_gpio;
+	struct gpio_desc *select_gpio;
+	struct mutex lock; /* serialize orientation and mode updates */
+	struct typec_switch_dev *sw;
+	struct typec_mux_dev *mux;
+	enum typec_orientation orientation;
+	unsigned long mode;
+};
+
+static void fusb340_update_locked(struct fusb340 *fusb)
+{
+	bool enable = fusb->mode == TYPEC_STATE_USB &&
+		      fusb->orientation != TYPEC_ORIENTATION_NONE;
+	bool select = fusb->orientation == TYPEC_ORIENTATION_REVERSE;
+
+	gpiod_set_value_cansleep(fusb->enable_gpio, enable);
+	gpiod_set_value_cansleep(fusb->select_gpio, select);
+}
+
+static int fusb340_switch_set(struct typec_switch_dev *sw,
+			      enum typec_orientation orientation)
+{
+	struct fusb340 *fusb = typec_switch_get_drvdata(sw);
+
+	mutex_lock(&fusb->lock);
+
+	if (fusb->orientation != orientation) {
+		fusb->orientation = orientation;
+		fusb340_update_locked(fusb);
+	}
+
+	mutex_unlock(&fusb->lock);
+
+	return 0;
+}
+
+static int fusb340_mux_set(struct typec_mux_dev *mux,
+			   struct typec_mux_state *state)
+{
+	struct fusb340 *fusb = typec_mux_get_drvdata(mux);
+	int ret = 0;
+
+	mutex_lock(&fusb->lock);
+
+	if (state->mode != TYPEC_STATE_SAFE && state->mode != TYPEC_STATE_USB) {
+		ret = -EOPNOTSUPP;
+		goto out_unlock;
+	}
+
+	if (fusb->mode != state->mode) {
+		fusb->mode = state->mode;
+		fusb340_update_locked(fusb);
+	}
+
+out_unlock:
+	mutex_unlock(&fusb->lock);
+
+	return ret;
+}
+
+static int fusb340_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct typec_switch_desc sw_desc = { };
+	struct typec_mux_desc mux_desc = { };
+	struct fusb340 *fusb;
+	int ret;
+
+	fusb = devm_kzalloc(dev, sizeof(*fusb), GFP_KERNEL);
+	if (!fusb)
+		return -ENOMEM;
+
+	fusb->orientation = TYPEC_ORIENTATION_NONE;
+	fusb->mode = TYPEC_STATE_SAFE;
+
+	fusb->enable_gpio = devm_gpiod_get(dev, "enable", GPIOD_OUT_LOW);
+	if (IS_ERR(fusb->enable_gpio))
+		return dev_err_probe(dev, PTR_ERR(fusb->enable_gpio),
+				     "failed to get enable gpio\n");
+
+	fusb->select_gpio = devm_gpiod_get(dev, "select", GPIOD_OUT_LOW);
+	if (IS_ERR(fusb->select_gpio))
+		return dev_err_probe(dev, PTR_ERR(fusb->select_gpio),
+				     "failed to get select gpio\n");
+
+	mutex_init(&fusb->lock);
+
+	sw_desc.drvdata = fusb;
+	sw_desc.fwnode = dev_fwnode(dev);
+	sw_desc.set = fusb340_switch_set;
+
+	fusb->sw = typec_switch_register(dev, &sw_desc);
+	if (IS_ERR(fusb->sw)) {
+		ret = dev_err_probe(dev, PTR_ERR(fusb->sw),
+				    "failed to register typec switch\n");
+		goto err_mutex_destroy;
+	}
+
+	mux_desc.drvdata = fusb;
+	mux_desc.fwnode = dev_fwnode(dev);
+	mux_desc.set = fusb340_mux_set;
+
+	fusb->mux = typec_mux_register(dev, &mux_desc);
+	if (IS_ERR(fusb->mux)) {
+		ret = dev_err_probe(dev, PTR_ERR(fusb->mux),
+				    "failed to register typec mux\n");
+		goto err_unregister_switch;
+	}
+
+	platform_set_drvdata(pdev, fusb);
+
+	return 0;
+
+err_unregister_switch:
+	typec_switch_unregister(fusb->sw);
+err_mutex_destroy:
+	mutex_destroy(&fusb->lock);
+	return ret;
+}
+
+static void fusb340_remove(struct platform_device *pdev)
+{
+	struct fusb340 *fusb = platform_get_drvdata(pdev);
+
+	gpiod_set_value_cansleep(fusb->enable_gpio, 0);
+	gpiod_set_value_cansleep(fusb->select_gpio, 0);
+
+	typec_mux_unregister(fusb->mux);
+	typec_switch_unregister(fusb->sw);
+	mutex_destroy(&fusb->lock);
+}
+
+static const struct of_device_id fusb340_of_match[] = {
+	{ .compatible = "onnn,fusb340" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, fusb340_of_match);
+
+static struct platform_driver fusb340_driver = {
+	.probe = fusb340_probe,
+	.remove = fusb340_remove,
+	.driver = {
+		.name = "fusb340",
+		.of_match_table = fusb340_of_match,
+	},
+};
+module_platform_driver(fusb340_driver);
+
+MODULE_DESCRIPTION("ON Semiconductor FUSB340 SuperSpeed switch driver");
+MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@xxxxxxxxxxx>");
+MODULE_LICENSE("GPL");

-- 
2.43.0