gpio: Add Intel USBIO GPIO driver

Add a a driver for the GPIO auxbus child device of the Intel USBIO USB
IO-expander used by the MIPI cameras on various new (Meteor Lake and
later) Intel laptops.

Reviewed-by: Linus Walleij <[e-mail]>
Acked-by: Bartosz Golaszewski <[e-mail]>
Co-developed-by: Hans de Goede <[e-mail]>
Signed-off-by: Hans de Goede <[e-mail]>
Signed-off-by: Israel Cepeda <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

MAINTAINERS

···
 M:	Hans de Goede <[e-mail]>
 R:	Sakari Ailus <[e-mail]>
 S:	Maintained
+F:	drivers/gpio/gpio-usbio.c
 F:	drivers/usb/misc/usbio.c
 F:	include/linux/usb/usbio.h
 

drivers/gpio/Kconfig

···
 	  GPIO driver for FTDI's MPSSE interface. These can do input and
 	  output. Each MPSSE provides 16 IO pins.
 
+config GPIO_USBIO
+	tristate "Intel USBIO GPIO support"
+	depends on USB_USBIO
+	default USB_USBIO
+	help
+	  Select this option to enable GPIO driver for the INTEL
+	  USBIO driver stack.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called gpio_usbio.
+
 endmenu
 
 menu "Virtual GPIO drivers"

drivers/gpio/Makefile

···
 obj-$(CONFIG_GPIO_TWL4030)		+= gpio-twl4030.o
 obj-$(CONFIG_GPIO_TWL6040)		+= gpio-twl6040.o
 obj-$(CONFIG_GPIO_UNIPHIER)		+= gpio-uniphier.o
+obj-$(CONFIG_GPIO_USBIO) 		+= gpio-usbio.o
 obj-$(CONFIG_GPIO_VF610)		+= gpio-vf610.o
 obj-$(CONFIG_GPIO_VIPERBOARD)		+= gpio-viperboard.o
 obj-$(CONFIG_GPIO_VIRTUSER)		+= gpio-virtuser.o

drivers/gpio/gpio-usbio.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2025 Intel Corporation.
+ * Copyright (c) 2025 Red Hat, Inc.
+ */
+
+#include <linux/acpi.h>
+#include <linux/auxiliary_bus.h>
+#include <linux/cleanup.h>
+#include <linux/device.h>
+#include <linux/gpio/driver.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/usb/usbio.h>
+
+struct usbio_gpio_bank {
+	u8 config[USBIO_GPIOSPERBANK];
+	u32 bitmap;
+};
+
+struct usbio_gpio {
+	struct mutex config_mutex; /* Protects banks[x].config */
+	struct usbio_gpio_bank banks[USBIO_MAX_GPIOBANKS];
+	struct gpio_chip gc;
+	struct auxiliary_device *adev;
+};
+
+static const struct acpi_device_id usbio_gpio_acpi_hids[] = {
+	{ "INTC1007" }, /* MTL */
+	{ "INTC10B2" }, /* ARL */
+	{ "INTC10B5" }, /* LNL */
+	{ "INTC10E2" }, /* PTL */
+	{ }
+};
+
+static void usbio_gpio_get_bank_and_pin(struct gpio_chip *gc, unsigned int offset,
+					struct usbio_gpio_bank **bank_ret,
+					unsigned int *pin_ret)
+{
+	struct usbio_gpio *gpio = gpiochip_get_data(gc);
+	struct device *dev = &gpio->adev->dev;
+	struct usbio_gpio_bank *bank;
+	unsigned int pin;
+
+	bank = &gpio->banks[offset / USBIO_GPIOSPERBANK];
+	pin = offset % USBIO_GPIOSPERBANK;
+	if (~bank->bitmap & BIT(pin)) {
+		/* The FW bitmap sometimes is invalid, warn and continue */
+		dev_warn_once(dev, FW_BUG "GPIO %u is not in FW pins bitmap\n", offset);
+	}
+
+	*bank_ret = bank;
+	*pin_ret = pin;
+}
+
+static int usbio_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
+{
+	struct usbio_gpio_bank *bank;
+	unsigned int pin;
+	u8 cfg;
+
+	usbio_gpio_get_bank_and_pin(gc, offset, &bank, &pin);
+
+	cfg = bank->config[pin] & USBIO_GPIO_PINMOD_MASK;
+
+	return (cfg == USBIO_GPIO_PINMOD_OUTPUT) ?
+		GPIO_LINE_DIRECTION_OUT : GPIO_LINE_DIRECTION_IN;
+}
+
+static int usbio_gpio_get(struct gpio_chip *gc, unsigned int offset)
+{
+	struct usbio_gpio *gpio = gpiochip_get_data(gc);
+	struct usbio_gpio_bank *bank;
+	struct usbio_gpio_rw gbuf;
+	unsigned int pin;
+	int ret;
+
+	usbio_gpio_get_bank_and_pin(gc, offset, &bank, &pin);
+
+	gbuf.bankid = offset / USBIO_GPIOSPERBANK;
+	gbuf.pincount  = 1;
+	gbuf.pin = pin;
+
+	ret = usbio_control_msg(gpio->adev, USBIO_PKTTYPE_GPIO, USBIO_GPIOCMD_READ,
+				&gbuf, sizeof(gbuf) - sizeof(gbuf.value),
+				&gbuf, sizeof(gbuf));
+	if (ret != sizeof(gbuf))
+		return (ret < 0) ? ret : -EPROTO;
+
+	return (le32_to_cpu(gbuf.value) >> pin) & 1;
+}
+
+static int usbio_gpio_set(struct gpio_chip *gc, unsigned int offset, int value)
+{
+	struct usbio_gpio *gpio = gpiochip_get_data(gc);
+	struct usbio_gpio_bank *bank;
+	struct usbio_gpio_rw gbuf;
+	unsigned int pin;
+
+	usbio_gpio_get_bank_and_pin(gc, offset, &bank, &pin);
+
+	gbuf.bankid = offset / USBIO_GPIOSPERBANK;
+	gbuf.pincount  = 1;
+	gbuf.pin = pin;
+	gbuf.value = cpu_to_le32(value << pin);
+
+	return usbio_control_msg(gpio->adev, USBIO_PKTTYPE_GPIO, USBIO_GPIOCMD_WRITE,
+				 &gbuf, sizeof(gbuf), NULL, 0);
+}
+
+static int usbio_gpio_update_config(struct gpio_chip *gc, unsigned int offset,
+				    u8 mask, u8 value)
+{
+	struct usbio_gpio *gpio = gpiochip_get_data(gc);
+	struct usbio_gpio_bank *bank;
+	struct usbio_gpio_init gbuf;
+	unsigned int pin;
+
+	usbio_gpio_get_bank_and_pin(gc, offset, &bank, &pin);
+
+	guard(mutex)(&gpio->config_mutex);
+
+	bank->config[pin] &= ~mask;
+	bank->config[pin] |= value;
+
+	gbuf.bankid = offset / USBIO_GPIOSPERBANK;
+	gbuf.config = bank->config[pin];
+	gbuf.pincount  = 1;
+	gbuf.pin = pin;
+
+	return usbio_control_msg(gpio->adev, USBIO_PKTTYPE_GPIO, USBIO_GPIOCMD_INIT,
+				 &gbuf, sizeof(gbuf), NULL, 0);
+}
+
+static int usbio_gpio_direction_input(struct gpio_chip *gc, unsigned int offset)
+{
+	return usbio_gpio_update_config(gc, offset, USBIO_GPIO_PINMOD_MASK,
+					USBIO_GPIO_SET_PINMOD(USBIO_GPIO_PINMOD_INPUT));
+}
+
+static int usbio_gpio_direction_output(struct gpio_chip *gc,
+		unsigned int offset, int value)
+{
+	int ret;
+
+	ret = usbio_gpio_update_config(gc, offset, USBIO_GPIO_PINMOD_MASK,
+				       USBIO_GPIO_SET_PINMOD(USBIO_GPIO_PINMOD_OUTPUT));
+	if (ret)
+		return ret;
+
+	return usbio_gpio_set(gc, offset, value);
+}
+
+static int usbio_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
+		unsigned long config)
+{
+	u8 value;
+
+	switch (pinconf_to_config_param(config)) {
+	case PIN_CONFIG_BIAS_PULL_PIN_DEFAULT:
+		value = USBIO_GPIO_SET_PINCFG(USBIO_GPIO_PINCFG_DEFAULT);
+		break;
+	case PIN_CONFIG_BIAS_PULL_UP:
+		value = USBIO_GPIO_SET_PINCFG(USBIO_GPIO_PINCFG_PULLUP);
+		break;
+	case PIN_CONFIG_BIAS_PULL_DOWN:
+		value = USBIO_GPIO_SET_PINCFG(USBIO_GPIO_PINCFG_PULLDOWN);
+		break;
+	case PIN_CONFIG_DRIVE_PUSH_PULL:
+		value = USBIO_GPIO_SET_PINCFG(USBIO_GPIO_PINCFG_PUSHPULL);
+		break;
+	default:
+		return -ENOTSUPP;
+	}
+
+	return usbio_gpio_update_config(gc, offset, USBIO_GPIO_PINCFG_MASK, value);
+}
+
+static int usbio_gpio_probe(struct auxiliary_device *adev,
+		const struct auxiliary_device_id *adev_id)
+{
+	struct usbio_gpio_bank_desc *bank_desc;
+	struct device *dev = &adev->dev;
+	struct usbio_gpio *gpio;
+	int bank, ret;
+
+	bank_desc = dev_get_platdata(dev);
+	if (!bank_desc)
+		return -EINVAL;
+
+	gpio = devm_kzalloc(dev, sizeof(*gpio), GFP_KERNEL);
+	if (!gpio)
+		return -ENOMEM;
+
+	ret = devm_mutex_init(dev, &gpio->config_mutex);
+	if (ret)
+		return ret;
+
+	gpio->adev = adev;
+
+	usbio_acpi_bind(gpio->adev, usbio_gpio_acpi_hids);
+
+	for (bank = 0; bank < USBIO_MAX_GPIOBANKS && bank_desc[bank].bmap; bank++)
+		gpio->banks[bank].bitmap = le32_to_cpu(bank_desc[bank].bmap);
+
+	gpio->gc.label = ACPI_COMPANION(dev) ?
+					acpi_dev_name(ACPI_COMPANION(dev)) : dev_name(dev);
+	gpio->gc.parent = dev;
+	gpio->gc.owner = THIS_MODULE;
+	gpio->gc.get_direction = usbio_gpio_get_direction;
+	gpio->gc.direction_input = usbio_gpio_direction_input;
+	gpio->gc.direction_output = usbio_gpio_direction_output;
+	gpio->gc.get = usbio_gpio_get;
+	gpio->gc.set = usbio_gpio_set;
+	gpio->gc.set_config = usbio_gpio_set_config;
+	gpio->gc.base = -1;
+	gpio->gc.ngpio = bank * USBIO_GPIOSPERBANK;
+	gpio->gc.can_sleep = true;
+
+	ret = devm_gpiochip_add_data(dev, &gpio->gc, gpio);
+	if (ret)
+		return ret;
+
+	if (has_acpi_companion(dev))
+		acpi_dev_clear_dependencies(ACPI_COMPANION(dev));
+
+	return 0;
+}
+
+static const struct auxiliary_device_id usbio_gpio_id_table[] = {
+	{ "usbio.usbio-gpio" },
+	{ }
+};
+MODULE_DEVICE_TABLE(auxiliary, usbio_gpio_id_table);
+
+static struct auxiliary_driver usbio_gpio_driver = {
+	.name = USBIO_GPIO_CLIENT,
+	.probe = usbio_gpio_probe,
+	.id_table = usbio_gpio_id_table
+};
+module_auxiliary_driver(usbio_gpio_driver);
+
+MODULE_DESCRIPTION("Intel USBIO GPIO driver");
+MODULE_AUTHOR("Israel Cepeda <[e-mail]>");
+MODULE_AUTHOR("Hans de Goede <[e-mail]>");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("USBIO");