[patch 23/32] greybus: bridged phy gpio driver

[Greg KH <gregkh@linuxfoundation.org>]

This driver implements the Greybus bridged phy gpio class protocol.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/greybus/gpio.c |  767 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 767 insertions(+)

--- /dev/null
+++ b/drivers/greybus/gpio.c
@@ -0,0 +1,767 @@
+/*
+ * GPIO Greybus driver.
+ *
+ * Copyright 2014 Google Inc.
+ * Copyright 2014 Linaro Ltd.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/gpio.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/mutex.h>
+
+#include "greybus.h"
+#include "gbphy.h"
+
+struct gb_gpio_line {
+	/* The following has to be an array of line_max entries */
+	/* --> make them just a flags field */
+	u8			active:    1,
+				direction: 1,	/* 0 = output, 1 = input */
+				value:     1;	/* 0 = low, 1 = high */
+	u16			debounce_usec;
+
+	u8			irq_type;
+	bool			irq_type_pending;
+	bool			masked;
+	bool			masked_pending;
+};
+
+struct gb_gpio_controller {
+	struct gbphy_device	*gbphy_dev;
+	struct gb_connection	*connection;
+	u8			line_max;	/* max line number */
+	struct gb_gpio_line	*lines;
+
+	struct gpio_chip	chip;
+	struct irq_chip		irqc;
+	struct irq_chip		*irqchip;
+	struct irq_domain	*irqdomain;
+	unsigned int		irq_base;
+	irq_flow_handler_t	irq_handler;
+	unsigned int		irq_default_type;
+	struct mutex		irq_lock;
+};
+#define gpio_chip_to_gb_gpio_controller(chip) \
+	container_of(chip, struct gb_gpio_controller, chip)
+#define irq_data_to_gpio_chip(d) (d->domain->host_data)
+
+static int gb_gpio_line_count_operation(struct gb_gpio_controller *ggc)
+{
+	struct gb_gpio_line_count_response response;
+	int ret;
+
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_LINE_COUNT,
+				NULL, 0, &response, sizeof(response));
+	if (!ret)
+		ggc->line_max = response.count;
+	return ret;
+}
+
+static int gb_gpio_activate_operation(struct gb_gpio_controller *ggc, u8 which)
+{
+	struct gb_gpio_activate_request request;
+	struct gbphy_device *gbphy_dev = ggc->gbphy_dev;
+	int ret;
+
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		return ret;
+
+	request.which = which;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_ACTIVATE,
+				 &request, sizeof(request), NULL, 0);
+	if (ret) {
+		gbphy_runtime_put_autosuspend(gbphy_dev);
+		return ret;
+	}
+
+	ggc->lines[which].active = true;
+
+	return 0;
+}
+
+static void gb_gpio_deactivate_operation(struct gb_gpio_controller *ggc,
+					u8 which)
+{
+	struct gbphy_device *gbphy_dev = ggc->gbphy_dev;
+	struct device *dev = &gbphy_dev->dev;
+	struct gb_gpio_deactivate_request request;
+	int ret;
+
+	request.which = which;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DEACTIVATE,
+				 &request, sizeof(request), NULL, 0);
+	if (ret) {
+		dev_err(dev, "failed to deactivate gpio %u\n", which);
+		goto out_pm_put;
+	}
+
+	ggc->lines[which].active = false;
+
+out_pm_put:
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+}
+
+static int gb_gpio_get_direction_operation(struct gb_gpio_controller *ggc,
+					u8 which)
+{
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_gpio_get_direction_request request;
+	struct gb_gpio_get_direction_response response;
+	int ret;
+	u8 direction;
+
+	request.which = which;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_DIRECTION,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret)
+		return ret;
+
+	direction = response.direction;
+	if (direction && direction != 1) {
+		dev_warn(dev, "gpio %u direction was %u (should be 0 or 1)\n",
+			 which, direction);
+	}
+	ggc->lines[which].direction = direction ? 1 : 0;
+	return 0;
+}
+
+static int gb_gpio_direction_in_operation(struct gb_gpio_controller *ggc,
+					u8 which)
+{
+	struct gb_gpio_direction_in_request request;
+	int ret;
+
+	request.which = which;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_IN,
+				&request, sizeof(request), NULL, 0);
+	if (!ret)
+		ggc->lines[which].direction = 1;
+	return ret;
+}
+
+static int gb_gpio_direction_out_operation(struct gb_gpio_controller *ggc,
+					u8 which, bool value_high)
+{
+	struct gb_gpio_direction_out_request request;
+	int ret;
+
+	request.which = which;
+	request.value = value_high ? 1 : 0;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_DIRECTION_OUT,
+				&request, sizeof(request), NULL, 0);
+	if (!ret)
+		ggc->lines[which].direction = 0;
+	return ret;
+}
+
+static int gb_gpio_get_value_operation(struct gb_gpio_controller *ggc,
+					u8 which)
+{
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_gpio_get_value_request request;
+	struct gb_gpio_get_value_response response;
+	int ret;
+	u8 value;
+
+	request.which = which;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_GET_VALUE,
+				&request, sizeof(request),
+				&response, sizeof(response));
+	if (ret) {
+		dev_err(dev, "failed to get value of gpio %u\n", which);
+		return ret;
+	}
+
+	value = response.value;
+	if (value && value != 1) {
+		dev_warn(dev, "gpio %u value was %u (should be 0 or 1)\n",
+			 which, value);
+	}
+	ggc->lines[which].value = value ? 1 : 0;
+	return 0;
+}
+
+static void gb_gpio_set_value_operation(struct gb_gpio_controller *ggc,
+					u8 which, bool value_high)
+{
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_gpio_set_value_request request;
+	int ret;
+
+	if (ggc->lines[which].direction == 1) {
+		dev_warn(dev, "refusing to set value of input gpio %u\n",
+			 which);
+		return;
+	}
+
+	request.which = which;
+	request.value = value_high ? 1 : 0;
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_VALUE,
+				&request, sizeof(request), NULL, 0);
+	if (ret) {
+		dev_err(dev, "failed to set value of gpio %u\n", which);
+		return;
+	}
+
+	ggc->lines[which].value = request.value;
+}
+
+static int gb_gpio_set_debounce_operation(struct gb_gpio_controller *ggc,
+					u8 which, u16 debounce_usec)
+{
+	struct gb_gpio_set_debounce_request request;
+	int ret;
+
+	request.which = which;
+	request.usec = cpu_to_le16(debounce_usec);
+	ret = gb_operation_sync(ggc->connection, GB_GPIO_TYPE_SET_DEBOUNCE,
+				&request, sizeof(request), NULL, 0);
+	if (!ret)
+		ggc->lines[which].debounce_usec = debounce_usec;
+	return ret;
+}
+
+static void _gb_gpio_irq_mask(struct gb_gpio_controller *ggc, u8 hwirq)
+{
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_gpio_irq_mask_request request;
+	int ret;
+
+	request.which = hwirq;
+	ret = gb_operation_sync(ggc->connection,
+				GB_GPIO_TYPE_IRQ_MASK,
+				&request, sizeof(request), NULL, 0);
+	if (ret)
+		dev_err(dev, "failed to mask irq: %d\n", ret);
+}
+
+static void _gb_gpio_irq_unmask(struct gb_gpio_controller *ggc, u8 hwirq)
+{
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_gpio_irq_unmask_request request;
+	int ret;
+
+	request.which = hwirq;
+	ret = gb_operation_sync(ggc->connection,
+				GB_GPIO_TYPE_IRQ_UNMASK,
+				&request, sizeof(request), NULL, 0);
+	if (ret)
+		dev_err(dev, "failed to unmask irq: %d\n", ret);
+}
+
+static void _gb_gpio_irq_set_type(struct gb_gpio_controller *ggc,
+					u8 hwirq, u8 type)
+{
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_gpio_irq_type_request request;
+	int ret;
+
+	request.which = hwirq;
+	request.type = type;
+
+	ret = gb_operation_sync(ggc->connection,
+				GB_GPIO_TYPE_IRQ_TYPE,
+				&request, sizeof(request), NULL, 0);
+	if (ret)
+		dev_err(dev, "failed to set irq type: %d\n", ret);
+}
+
+static void gb_gpio_irq_mask(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	struct gb_gpio_line *line = &ggc->lines[d->hwirq];
+
+	line->masked = true;
+	line->masked_pending = true;
+}
+
+static void gb_gpio_irq_unmask(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	struct gb_gpio_line *line = &ggc->lines[d->hwirq];
+
+	line->masked = false;
+	line->masked_pending = true;
+}
+
+static int gb_gpio_irq_set_type(struct irq_data *d, unsigned int type)
+{
+	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	struct gb_gpio_line *line = &ggc->lines[d->hwirq];
+	struct device *dev = &ggc->gbphy_dev->dev;
+	u8 irq_type;
+
+	switch (type) {
+	case IRQ_TYPE_NONE:
+		irq_type = GB_GPIO_IRQ_TYPE_NONE;
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		irq_type = GB_GPIO_IRQ_TYPE_EDGE_RISING;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		irq_type = GB_GPIO_IRQ_TYPE_EDGE_FALLING;
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		irq_type = GB_GPIO_IRQ_TYPE_EDGE_BOTH;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		irq_type = GB_GPIO_IRQ_TYPE_LEVEL_LOW;
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		irq_type = GB_GPIO_IRQ_TYPE_LEVEL_HIGH;
+		break;
+	default:
+		dev_err(dev, "unsupported irq type: %u\n", type);
+		return -EINVAL;
+	}
+
+	line->irq_type = irq_type;
+	line->irq_type_pending = true;
+
+	return 0;
+}
+
+static void gb_gpio_irq_bus_lock(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	mutex_lock(&ggc->irq_lock);
+}
+
+static void gb_gpio_irq_bus_sync_unlock(struct irq_data *d)
+{
+	struct gpio_chip *chip = irq_data_to_gpio_chip(d);
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	struct gb_gpio_line *line = &ggc->lines[d->hwirq];
+
+	if (line->irq_type_pending) {
+		_gb_gpio_irq_set_type(ggc, d->hwirq, line->irq_type);
+		line->irq_type_pending = false;
+	}
+
+	if (line->masked_pending) {
+		if (line->masked)
+			_gb_gpio_irq_mask(ggc, d->hwirq);
+		else
+			_gb_gpio_irq_unmask(ggc, d->hwirq);
+		line->masked_pending = false;
+	}
+
+	mutex_unlock(&ggc->irq_lock);
+}
+
+static int gb_gpio_request_handler(struct gb_operation *op)
+{
+	struct gb_connection *connection = op->connection;
+	struct gb_gpio_controller *ggc = gb_connection_get_data(connection);
+	struct device *dev = &ggc->gbphy_dev->dev;
+	struct gb_message *request;
+	struct gb_gpio_irq_event_request *event;
+	u8 type = op->type;
+	int irq;
+	struct irq_desc *desc;
+
+	if (type != GB_GPIO_TYPE_IRQ_EVENT) {
+		dev_err(dev, "unsupported unsolicited request: %u\n", type);
+		return -EINVAL;
+	}
+
+	request = op->request;
+
+	if (request->payload_size < sizeof(*event)) {
+		dev_err(dev, "short event received (%zu < %zu)\n",
+			request->payload_size, sizeof(*event));
+		return -EINVAL;
+	}
+
+	event = request->payload;
+	if (event->which > ggc->line_max) {
+		dev_err(dev, "invalid hw irq: %d\n", event->which);
+		return -EINVAL;
+	}
+
+	irq = irq_find_mapping(ggc->irqdomain, event->which);
+	if (!irq) {
+		dev_err(dev, "failed to find IRQ\n");
+		return -EINVAL;
+	}
+	desc = irq_to_desc(irq);
+	if (!desc) {
+		dev_err(dev, "failed to look up irq\n");
+		return -EINVAL;
+	}
+
+	local_irq_disable();
+	generic_handle_irq_desc(desc);
+	local_irq_enable();
+
+	return 0;
+}
+
+static int gb_gpio_request(struct gpio_chip *chip, unsigned offset)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	return gb_gpio_activate_operation(ggc, (u8)offset);
+}
+
+static void gb_gpio_free(struct gpio_chip *chip, unsigned offset)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	gb_gpio_deactivate_operation(ggc, (u8)offset);
+}
+
+static int gb_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	u8 which;
+	int ret;
+
+	which = (u8)offset;
+	ret = gb_gpio_get_direction_operation(ggc, which);
+	if (ret)
+		return ret;
+
+	return ggc->lines[which].direction ? 1 : 0;
+}
+
+static int gb_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	return gb_gpio_direction_in_operation(ggc, (u8)offset);
+}
+
+static int gb_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
+					int value)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	return gb_gpio_direction_out_operation(ggc, (u8)offset, !!value);
+}
+
+static int gb_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	u8 which;
+	int ret;
+
+	which = (u8)offset;
+	ret = gb_gpio_get_value_operation(ggc, which);
+	if (ret)
+		return ret;
+
+	return ggc->lines[which].value;
+}
+
+static void gb_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	gb_gpio_set_value_operation(ggc, (u8)offset, !!value);
+}
+
+static int gb_gpio_set_debounce(struct gpio_chip *chip, unsigned offset,
+					unsigned debounce)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+	u16 usec;
+
+	if (debounce > U16_MAX)
+		return -EINVAL;
+	usec = (u16)debounce;
+
+	return gb_gpio_set_debounce_operation(ggc, (u8)offset, usec);
+}
+
+static int gb_gpio_controller_setup(struct gb_gpio_controller *ggc)
+{
+	int ret;
+
+	/* Now find out how many lines there are */
+	ret = gb_gpio_line_count_operation(ggc);
+	if (ret)
+		return ret;
+
+	ggc->lines = kcalloc(ggc->line_max + 1, sizeof(*ggc->lines),
+			     GFP_KERNEL);
+	if (!ggc->lines)
+		return -ENOMEM;
+
+	return ret;
+}
+
+/**
+ * gb_gpio_irq_map() - maps an IRQ into a GB gpio irqchip
+ * @d: the irqdomain used by this irqchip
+ * @irq: the global irq number used by this GB gpio irqchip irq
+ * @hwirq: the local IRQ/GPIO line offset on this GB gpio
+ *
+ * This function will set up the mapping for a certain IRQ line on a
+ * GB gpio by assigning the GB gpio as chip data, and using the irqchip
+ * stored inside the GB gpio.
+ */
+static int gb_gpio_irq_map(struct irq_domain *domain, unsigned int irq,
+			   irq_hw_number_t hwirq)
+{
+	struct gpio_chip *chip = domain->host_data;
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	irq_set_chip_data(irq, ggc);
+	irq_set_chip_and_handler(irq, ggc->irqchip, ggc->irq_handler);
+	irq_set_noprobe(irq);
+	/*
+	 * No set-up of the hardware will happen if IRQ_TYPE_NONE
+	 * is passed as default type.
+	 */
+	if (ggc->irq_default_type != IRQ_TYPE_NONE)
+		irq_set_irq_type(irq, ggc->irq_default_type);
+
+	return 0;
+}
+
+static void gb_gpio_irq_unmap(struct irq_domain *d, unsigned int irq)
+{
+	irq_set_chip_and_handler(irq, NULL, NULL);
+	irq_set_chip_data(irq, NULL);
+}
+
+static const struct irq_domain_ops gb_gpio_domain_ops = {
+	.map	= gb_gpio_irq_map,
+	.unmap	= gb_gpio_irq_unmap,
+};
+
+/**
+ * gb_gpio_irqchip_remove() - removes an irqchip added to a gb_gpio_controller
+ * @ggc: the gb_gpio_controller to remove the irqchip from
+ *
+ * This is called only from gb_gpio_remove()
+ */
+static void gb_gpio_irqchip_remove(struct gb_gpio_controller *ggc)
+{
+	unsigned int offset;
+
+	/* Remove all IRQ mappings and delete the domain */
+	if (ggc->irqdomain) {
+		for (offset = 0; offset < (ggc->line_max + 1); offset++)
+			irq_dispose_mapping(irq_find_mapping(ggc->irqdomain, offset));
+		irq_domain_remove(ggc->irqdomain);
+	}
+
+	if (ggc->irqchip) {
+		ggc->irqchip = NULL;
+	}
+}
+
+/**
+ * gb_gpio_irqchip_add() - adds an irqchip to a gpio chip
+ * @chip: the gpio chip to add the irqchip to
+ * @irqchip: the irqchip to add to the adapter
+ * @first_irq: if not dynamically assigned, the base (first) IRQ to
+ * allocate gpio irqs from
+ * @handler: the irq handler to use (often a predefined irq core function)
+ * @type: the default type for IRQs on this irqchip, pass IRQ_TYPE_NONE
+ * to have the core avoid setting up any default type in the hardware.
+ *
+ * This function closely associates a certain irqchip with a certain
+ * gpio chip, providing an irq domain to translate the local IRQs to
+ * global irqs, and making sure that the gpio chip
+ * is passed as chip data to all related functions. Driver callbacks
+ * need to use container_of() to get their local state containers back
+ * from the gpio chip passed as chip data. An irqdomain will be stored
+ * in the gpio chip that shall be used by the driver to handle IRQ number
+ * translation. The gpio chip will need to be initialized and registered
+ * before calling this function.
+ */
+static int gb_gpio_irqchip_add(struct gpio_chip *chip,
+			 struct irq_chip *irqchip,
+			 unsigned int first_irq,
+			 irq_flow_handler_t handler,
+			 unsigned int type)
+{
+	struct gb_gpio_controller *ggc;
+	unsigned int offset;
+	unsigned irq_base;
+
+	if (!chip || !irqchip)
+		return -EINVAL;
+
+	ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	ggc->irqchip = irqchip;
+	ggc->irq_handler = handler;
+	ggc->irq_default_type = type;
+	ggc->irqdomain = irq_domain_add_simple(NULL,
+					ggc->line_max + 1, first_irq,
+					&gb_gpio_domain_ops, chip);
+	if (!ggc->irqdomain) {
+		ggc->irqchip = NULL;
+		return -EINVAL;
+	}
+
+	/*
+	 * Prepare the mapping since the irqchip shall be orthogonal to
+	 * any gpio calls. If the first_irq was zero, this is
+	 * necessary to allocate descriptors for all IRQs.
+	 */
+	for (offset = 0; offset < (ggc->line_max + 1); offset++) {
+		irq_base = irq_create_mapping(ggc->irqdomain, offset);
+		if (offset == 0)
+			ggc->irq_base = irq_base;
+	}
+
+	return 0;
+}
+
+static int gb_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
+{
+	struct gb_gpio_controller *ggc = gpio_chip_to_gb_gpio_controller(chip);
+
+	return irq_find_mapping(ggc->irqdomain, offset);
+}
+
+static int gb_gpio_probe(struct gbphy_device *gbphy_dev,
+			 const struct gbphy_device_id *id)
+{
+	struct gb_connection *connection;
+	struct gb_gpio_controller *ggc;
+	struct gpio_chip *gpio;
+	struct irq_chip *irqc;
+	int ret;
+
+	ggc = kzalloc(sizeof(*ggc), GFP_KERNEL);
+	if (!ggc)
+		return -ENOMEM;
+
+	connection = gb_connection_create(gbphy_dev->bundle,
+					  le16_to_cpu(gbphy_dev->cport_desc->id),
+					  gb_gpio_request_handler);
+	if (IS_ERR(connection)) {
+		ret = PTR_ERR(connection);
+		goto exit_ggc_free;
+	}
+
+	ggc->connection = connection;
+	gb_connection_set_data(connection, ggc);
+	ggc->gbphy_dev = gbphy_dev;
+	gb_gbphy_set_data(gbphy_dev, ggc);
+
+	ret = gb_connection_enable_tx(connection);
+	if (ret)
+		goto exit_connection_destroy;
+
+	ret = gb_gpio_controller_setup(ggc);
+	if (ret)
+		goto exit_connection_disable;
+
+	irqc = &ggc->irqc;
+	irqc->irq_mask = gb_gpio_irq_mask;
+	irqc->irq_unmask = gb_gpio_irq_unmask;
+	irqc->irq_set_type = gb_gpio_irq_set_type;
+	irqc->irq_bus_lock = gb_gpio_irq_bus_lock;
+	irqc->irq_bus_sync_unlock = gb_gpio_irq_bus_sync_unlock;
+	irqc->name = "greybus_gpio";
+
+	mutex_init(&ggc->irq_lock);
+
+	gpio = &ggc->chip;
+
+	gpio->label = "greybus_gpio";
+	gpio->parent = &gbphy_dev->dev;
+	gpio->owner = THIS_MODULE;
+
+	gpio->request = gb_gpio_request;
+	gpio->free = gb_gpio_free;
+	gpio->get_direction = gb_gpio_get_direction;
+	gpio->direction_input = gb_gpio_direction_input;
+	gpio->direction_output = gb_gpio_direction_output;
+	gpio->get = gb_gpio_get;
+	gpio->set = gb_gpio_set;
+	gpio->set_debounce = gb_gpio_set_debounce;
+	gpio->to_irq = gb_gpio_to_irq;
+	gpio->base = -1;		/* Allocate base dynamically */
+	gpio->ngpio = ggc->line_max + 1;
+	gpio->can_sleep = true;
+
+	ret = gb_connection_enable(connection);
+	if (ret)
+		goto exit_line_free;
+
+	ret = gpiochip_add(gpio);
+	if (ret) {
+		dev_err(&connection->bundle->dev,
+			"failed to add gpio chip: %d\n", ret);
+		goto exit_line_free;
+	}
+
+	ret = gb_gpio_irqchip_add(gpio, irqc, 0,
+				   handle_level_irq, IRQ_TYPE_NONE);
+	if (ret) {
+		dev_err(&connection->bundle->dev,
+			"failed to add irq chip: %d\n", ret);
+		goto exit_gpiochip_remove;
+	}
+
+	gbphy_runtime_put_autosuspend(gbphy_dev);
+	return 0;
+
+exit_gpiochip_remove:
+	gpiochip_remove(gpio);
+exit_line_free:
+	kfree(ggc->lines);
+exit_connection_disable:
+	gb_connection_disable(connection);
+exit_connection_destroy:
+	gb_connection_destroy(connection);
+exit_ggc_free:
+	kfree(ggc);
+	return ret;
+}
+
+static void gb_gpio_remove(struct gbphy_device *gbphy_dev)
+{
+	struct gb_gpio_controller *ggc = gb_gbphy_get_data(gbphy_dev);
+	struct gb_connection *connection = ggc->connection;
+	int ret;
+
+	ret = gbphy_runtime_get_sync(gbphy_dev);
+	if (ret)
+		gbphy_runtime_get_noresume(gbphy_dev);
+
+	gb_connection_disable_rx(connection);
+	gb_gpio_irqchip_remove(ggc);
+	gpiochip_remove(&ggc->chip);
+	gb_connection_disable(connection);
+	gb_connection_destroy(connection);
+	kfree(ggc->lines);
+	kfree(ggc);
+}
+
+static const struct gbphy_device_id gb_gpio_id_table[] = {
+	{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_GPIO) },
+	{ },
+};
+MODULE_DEVICE_TABLE(gbphy, gb_gpio_id_table);
+
+static struct gbphy_driver gpio_driver = {
+	.name		= "gpio",
+	.probe		= gb_gpio_probe,
+	.remove		= gb_gpio_remove,
+	.id_table	= gb_gpio_id_table,
+};
+
+module_gbphy_driver(gpio_driver);
+MODULE_LICENSE("GPL v2");