drivers/i2c/busses/i2c-cht-wc.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Intel CHT Whiskey Cove PMIC I2C Master driver
  * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
  *
  * Based on various non upstream patches to support the CHT Whiskey Cove PMIC:
  * Copyright (C) 2011 - 2014 Intel Corporation. All rights reserved.
  */

 #include <linux/acpi.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
 #include <linux/mfd/intel_soc_pmic.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/power/bq24190_charger.h>
 #include <linux/slab.h>

 #define CHT_WC_I2C_CTRL			0x5e24
 #define CHT_WC_I2C_CTRL_WR		BIT(0)
 #define CHT_WC_I2C_CTRL_RD		BIT(1)
 #define CHT_WC_I2C_CLIENT_ADDR		0x5e25
 #define CHT_WC_I2C_REG_OFFSET		0x5e26
 #define CHT_WC_I2C_WRDATA		0x5e27
 #define CHT_WC_I2C_RDDATA		0x5e28

 #define CHT_WC_EXTCHGRIRQ		0x6e0a
 #define CHT_WC_EXTCHGRIRQ_CLIENT_IRQ	BIT(0)
 #define CHT_WC_EXTCHGRIRQ_WRITE_IRQ	BIT(1)
 #define CHT_WC_EXTCHGRIRQ_READ_IRQ	BIT(2)
 #define CHT_WC_EXTCHGRIRQ_NACK_IRQ	BIT(3)
 #define CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK	((u8)GENMASK(3, 1))
 #define CHT_WC_EXTCHGRIRQ_MSK		0x6e17

 struct cht_wc_i2c_adap {
 	struct i2c_adapter adapter;
 	wait_queue_head_t wait;
 	struct irq_chip irqchip;
 	struct mutex adap_lock;
 	struct mutex irqchip_lock;
 	struct regmap *regmap;
 	struct irq_domain *irq_domain;
 	struct i2c_client *client;
 	int client_irq;
 	u8 irq_mask;
 	u8 old_irq_mask;
 	int read_data;
 	bool io_error;
 	bool done;
 };

 static irqreturn_t cht_wc_i2c_adap_thread_handler(int id, void *data)
 {
 	struct cht_wc_i2c_adap *adap = data;
 	int ret, reg;

 	mutex_lock(&adap->adap_lock);

 	/* Read IRQs */
 	ret = regmap_read(adap->regmap, CHT_WC_EXTCHGRIRQ, &reg);
 	if (ret) {
 		dev_err(&adap->adapter.dev, "Error reading extchgrirq reg\n");
 		mutex_unlock(&adap->adap_lock);
 		return IRQ_NONE;
 	}

 	reg &= ~adap->irq_mask;

 	/* Reads must be acked after reading the received data. */
 	ret = regmap_read(adap->regmap, CHT_WC_I2C_RDDATA, &adap->read_data);
 	if (ret)
 		adap->io_error = true;

 	/*
 	 * Immediately ack IRQs, so that if new IRQs arrives while we're
 	 * handling the previous ones our irq will re-trigger when we're done.
 	 */
 	ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ, reg);
 	if (ret)
 		dev_err(&adap->adapter.dev, "Error writing extchgrirq reg\n");

 	if (reg & CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK) {
 		adap->io_error |= !!(reg & CHT_WC_EXTCHGRIRQ_NACK_IRQ);
 		adap->done = true;
 	}

 	mutex_unlock(&adap->adap_lock);

 	if (reg & CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK)
 		wake_up(&adap->wait);

 	/*
 	 * Do NOT use handle_nested_irq here, the client irq handler will
 	 * likely want to do i2c transfers and the i2c controller uses this
 	 * interrupt handler as well, so running the client irq handler from
 	 * this thread will cause things to lock up.
 	 */
 	if (reg & CHT_WC_EXTCHGRIRQ_CLIENT_IRQ) {
 		/*
 		 * generic_handle_irq expects local IRQs to be disabled
 		 * as normally it is called from interrupt context.
 		 */
 		local_irq_disable();
 		generic_handle_irq(adap->client_irq);
 		local_irq_enable();
 	}

 	return IRQ_HANDLED;
 }

 static u32 cht_wc_i2c_adap_master_func(struct i2c_adapter *adap)
 {
 	/* This i2c adapter only supports SMBUS byte transfers */
 	return I2C_FUNC_SMBUS_BYTE_DATA;
 }

 static int cht_wc_i2c_adap_smbus_xfer(struct i2c_adapter *_adap, u16 addr,
 				      unsigned short flags, char read_write,
 				      u8 command, int size,
 				      union i2c_smbus_data *data)
 {
 	struct cht_wc_i2c_adap *adap = i2c_get_adapdata(_adap);
 	int ret;

 	mutex_lock(&adap->adap_lock);
 	adap->io_error = false;
 	adap->done = false;
 	mutex_unlock(&adap->adap_lock);

 	ret = regmap_write(adap->regmap, CHT_WC_I2C_CLIENT_ADDR, addr);
 	if (ret)
 		return ret;

 	if (read_write == I2C_SMBUS_WRITE) {
 		ret = regmap_write(adap->regmap, CHT_WC_I2C_WRDATA, data->byte);
 		if (ret)
 			return ret;
 	}

 	ret = regmap_write(adap->regmap, CHT_WC_I2C_REG_OFFSET, command);
 	if (ret)
 		return ret;

 	ret = regmap_write(adap->regmap, CHT_WC_I2C_CTRL,
 			   (read_write == I2C_SMBUS_WRITE) ?
 			   CHT_WC_I2C_CTRL_WR : CHT_WC_I2C_CTRL_RD);
 	if (ret)
 		return ret;

 	ret = wait_event_timeout(adap->wait, adap->done, msecs_to_jiffies(30));
 	if (ret == 0) {
 		/*
 		 * The CHT GPIO controller serializes all IRQs, sometimes
 		 * causing significant delays, check status manually.
 		 */
 		cht_wc_i2c_adap_thread_handler(0, adap);
 		if (!adap->done)
 			return -ETIMEDOUT;
 	}

 	ret = 0;
 	mutex_lock(&adap->adap_lock);
 	if (adap->io_error)
 		ret = -EIO;
 	else if (read_write == I2C_SMBUS_READ)
 		data->byte = adap->read_data;
 	mutex_unlock(&adap->adap_lock);

 	return ret;
 }

 static const struct i2c_algorithm cht_wc_i2c_adap_algo = {
 	.functionality = cht_wc_i2c_adap_master_func,
 	.smbus_xfer = cht_wc_i2c_adap_smbus_xfer,
 };

 /*
  * We are an i2c-adapter which itself is part of an i2c-client. This means that
  * transfers done through us take adapter->bus_lock twice, once for our parent
  * i2c-adapter and once to take our own bus_lock. Lockdep does not like this
  * nested locking, to make lockdep happy in the case of busses with muxes, the
  * i2c-core's i2c_adapter_lock_bus function calls:
  * rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
  *
  * But i2c_adapter_depth only works when the direct parent of the adapter is
  * another adapter, as it is only meant for muxes. In our case there is an
  * i2c-client and MFD instantiated platform_device in the parent->child chain
  * between the 2 devices.
  *
  * So we override the default i2c_lock_operations and pass a hardcoded
  * depth of 1 to rt_mutex_lock_nested, to make lockdep happy.
  *
  * Note that if there were to be a mux attached to our adapter, this would
  * break things again since the i2c-mux code expects the root-adapter to have
  * a locking depth of 0. But we always have only 1 client directly attached
  * in the form of the Charger IC paired with the CHT Whiskey Cove PMIC.
  */
 static void cht_wc_i2c_adap_lock_bus(struct i2c_adapter *adapter,
 				 unsigned int flags)
 {
 	rt_mutex_lock_nested(&adapter->bus_lock, 1);
 }

 static int cht_wc_i2c_adap_trylock_bus(struct i2c_adapter *adapter,
 				   unsigned int flags)
 {
 	return rt_mutex_trylock(&adapter->bus_lock);
 }

 static void cht_wc_i2c_adap_unlock_bus(struct i2c_adapter *adapter,
 				   unsigned int flags)
 {
 	rt_mutex_unlock(&adapter->bus_lock);
 }

 static const struct i2c_lock_operations cht_wc_i2c_adap_lock_ops = {
 	.lock_bus =    cht_wc_i2c_adap_lock_bus,
 	.trylock_bus = cht_wc_i2c_adap_trylock_bus,
 	.unlock_bus =  cht_wc_i2c_adap_unlock_bus,
 };

 /**** irqchip for the client connected to the extchgr i2c adapter ****/
 static void cht_wc_i2c_irq_lock(struct irq_data *data)
 {
 	struct cht_wc_i2c_adap *adap = irq_data_get_irq_chip_data(data);

 	mutex_lock(&adap->irqchip_lock);
 }

 static void cht_wc_i2c_irq_sync_unlock(struct irq_data *data)
 {
 	struct cht_wc_i2c_adap *adap = irq_data_get_irq_chip_data(data);
 	int ret;

 	if (adap->irq_mask != adap->old_irq_mask) {
 		ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ_MSK,
 				   adap->irq_mask);
 		if (ret == 0)
 			adap->old_irq_mask = adap->irq_mask;
 		else
 			dev_err(&adap->adapter.dev, "Error writing EXTCHGRIRQ_MSK\n");
 	}

 	mutex_unlock(&adap->irqchip_lock);
 }

 static void cht_wc_i2c_irq_enable(struct irq_data *data)
 {
 	struct cht_wc_i2c_adap *adap = irq_data_get_irq_chip_data(data);

 	adap->irq_mask &= ~CHT_WC_EXTCHGRIRQ_CLIENT_IRQ;
 }

 static void cht_wc_i2c_irq_disable(struct irq_data *data)
 {
 	struct cht_wc_i2c_adap *adap = irq_data_get_irq_chip_data(data);

 	adap->irq_mask |= CHT_WC_EXTCHGRIRQ_CLIENT_IRQ;
 }

 static const struct irq_chip cht_wc_i2c_irq_chip = {
 	.irq_bus_lock		= cht_wc_i2c_irq_lock,
 	.irq_bus_sync_unlock	= cht_wc_i2c_irq_sync_unlock,
 	.irq_disable		= cht_wc_i2c_irq_disable,
 	.irq_enable		= cht_wc_i2c_irq_enable,
 	.name			= "cht_wc_ext_chrg_irq_chip",
 };

 static const char * const bq24190_suppliers[] = {
 	"tcpm-source-psy-i2c-fusb302" };

 static const struct property_entry bq24190_props[] = {
 	PROPERTY_ENTRY_STRING_ARRAY("supplied-from", bq24190_suppliers),
 	PROPERTY_ENTRY_BOOL("omit-battery-class"),
 	PROPERTY_ENTRY_BOOL("disable-reset"),
 	{ }
 };

 static const struct software_node bq24190_node = {
 	.properties = bq24190_props,
 };

 static struct regulator_consumer_supply fusb302_consumer = {
 	.supply = "vbus",
 	/* Must match fusb302 dev_name in intel_cht_int33fe.c */
 	.dev_name = "i2c-fusb302",
 };

 static const struct regulator_init_data bq24190_vbus_init_data = {
 	.constraints = {
 		/* The name is used in intel_cht_int33fe.c do not change. */
 		.name = "cht_wc_usb_typec_vbus",
 		.valid_ops_mask = REGULATOR_CHANGE_STATUS,
 	},
 	.consumer_supplies = &fusb302_consumer,
 	.num_consumer_supplies = 1,
 };

 static struct bq24190_platform_data bq24190_pdata = {
 	.regulator_init_data = &bq24190_vbus_init_data,
 };

 static int cht_wc_i2c_adap_i2c_probe(struct platform_device *pdev)
 {
 	struct intel_soc_pmic *pmic = dev_get_drvdata(pdev->dev.parent);
 	struct cht_wc_i2c_adap *adap;
 	struct i2c_board_info board_info = {
 		.type = "bq24190",
 		.addr = 0x6b,
 		.dev_name = "bq24190",
 		.swnode = &bq24190_node,
 		.platform_data = &bq24190_pdata,
 	};
 	int ret, reg, irq;

 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
 		return irq;

 	adap = devm_kzalloc(&pdev->dev, sizeof(*adap), GFP_KERNEL);
 	if (!adap)
 		return -ENOMEM;

 	init_waitqueue_head(&adap->wait);
 	mutex_init(&adap->adap_lock);
 	mutex_init(&adap->irqchip_lock);
 	adap->irqchip = cht_wc_i2c_irq_chip;
 	adap->regmap = pmic->regmap;
 	adap->adapter.owner = THIS_MODULE;
 	adap->adapter.class = I2C_CLASS_HWMON;
 	adap->adapter.algo = &cht_wc_i2c_adap_algo;
 	adap->adapter.lock_ops = &cht_wc_i2c_adap_lock_ops;
 	strlcpy(adap->adapter.name, "PMIC I2C Adapter",
 		sizeof(adap->adapter.name));
 	adap->adapter.dev.parent = &pdev->dev;

 	/* Clear and activate i2c-adapter interrupts, disable client IRQ */
 	adap->old_irq_mask = adap->irq_mask = ~CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK;

 	ret = regmap_read(adap->regmap, CHT_WC_I2C_RDDATA, &reg);
 	if (ret)
 		return ret;

 	ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ, ~adap->irq_mask);
 	if (ret)
 		return ret;

 	ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ_MSK, adap->irq_mask);
 	if (ret)
 		return ret;

 	/* Alloc and register client IRQ */
 	adap->irq_domain = irq_domain_add_linear(NULL, 1, &irq_domain_simple_ops, NULL);
 	if (!adap->irq_domain)
 		return -ENOMEM;

 	adap->client_irq = irq_create_mapping(adap->irq_domain, 0);
 	if (!adap->client_irq) {
 		ret = -ENOMEM;
 		goto remove_irq_domain;
 	}

 	irq_set_chip_data(adap->client_irq, adap);
 	irq_set_chip_and_handler(adap->client_irq, &adap->irqchip,
 				 handle_simple_irq);

 	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
 					cht_wc_i2c_adap_thread_handler,
 					IRQF_ONESHOT, "PMIC I2C Adapter", adap);
 	if (ret)
 		goto remove_irq_domain;

 	i2c_set_adapdata(&adap->adapter, adap);
 	ret = i2c_add_adapter(&adap->adapter);
 	if (ret)
 		goto remove_irq_domain;

 	/*
 	 * Normally the Whiskey Cove PMIC is paired with a TI bq24292i charger,
 	 * connected to this i2c bus, and a max17047 fuel-gauge and a fusb302
 	 * USB Type-C controller connected to another i2c bus. In this setup
 	 * the max17047 and fusb302 devices are enumerated through an INT33FE
 	 * ACPI device. If this device is present register an i2c-client for
 	 * the TI bq24292i charger.
 	 */
 	if (acpi_dev_present("INT33FE", NULL, -1)) {
 		board_info.irq = adap->client_irq;
 		adap->client = i2c_new_client_device(&adap->adapter, &board_info);
 		if (IS_ERR(adap->client)) {
 			ret = PTR_ERR(adap->client);
 			goto del_adapter;
 		}
 	}

 	platform_set_drvdata(pdev, adap);
 	return 0;

 del_adapter:
 	i2c_del_adapter(&adap->adapter);
 remove_irq_domain:
 	irq_domain_remove(adap->irq_domain);
 	return ret;
 }

 static int cht_wc_i2c_adap_i2c_remove(struct platform_device *pdev)
 {
 	struct cht_wc_i2c_adap *adap = platform_get_drvdata(pdev);

 	i2c_unregister_device(adap->client);
 	i2c_del_adapter(&adap->adapter);
 	irq_domain_remove(adap->irq_domain);

 	return 0;
 }

 static const struct platform_device_id cht_wc_i2c_adap_id_table[] = {
 	{ .name = "cht_wcove_ext_chgr" },
 	{},
 };
 MODULE_DEVICE_TABLE(platform, cht_wc_i2c_adap_id_table);

 static struct platform_driver cht_wc_i2c_adap_driver = {
 	.probe = cht_wc_i2c_adap_i2c_probe,
 	.remove = cht_wc_i2c_adap_i2c_remove,
 	.driver = {
 		.name = "cht_wcove_ext_chgr",
 	},
 	.id_table = cht_wc_i2c_adap_id_table,
 };
 module_platform_driver(cht_wc_i2c_adap_driver);

 MODULE_DESCRIPTION("Intel CHT Whiskey Cove PMIC I2C Master driver");
 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Intel CHT Whiskey Cove PMIC I2C Master driver
	* Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
	*
	* Based on various non upstream patches to support the CHT Whiskey Cove PMIC:
	* Copyright (C) 2011 - 2014 Intel Corporation. All rights reserved.
	*/

	#include <linux/acpi.h>
	#include <linux/completion.h>
	#include <linux/delay.h>
	#include <linux/i2c.h>
	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/irqdomain.h>
	#include <linux/mfd/intel_soc_pmic.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/power/bq24190_charger.h>
	#include <linux/slab.h>

	#define CHT_WC_I2C_CTRL 0x5e24
	#define CHT_WC_I2C_CTRL_WR BIT(0)
	#define CHT_WC_I2C_CTRL_RD BIT(1)
	#define CHT_WC_I2C_CLIENT_ADDR 0x5e25
	#define CHT_WC_I2C_REG_OFFSET 0x5e26
	#define CHT_WC_I2C_WRDATA 0x5e27
	#define CHT_WC_I2C_RDDATA 0x5e28

	#define CHT_WC_EXTCHGRIRQ 0x6e0a
	#define CHT_WC_EXTCHGRIRQ_CLIENT_IRQ BIT(0)
	#define CHT_WC_EXTCHGRIRQ_WRITE_IRQ BIT(1)
	#define CHT_WC_EXTCHGRIRQ_READ_IRQ BIT(2)
	#define CHT_WC_EXTCHGRIRQ_NACK_IRQ BIT(3)
	#define CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK ((u8)GENMASK(3, 1))
	#define CHT_WC_EXTCHGRIRQ_MSK 0x6e17

	struct cht_wc_i2c_adap {
	struct i2c_adapter adapter;
	wait_queue_head_t wait;
	struct irq_chip irqchip;
	struct mutex adap_lock;
	struct mutex irqchip_lock;
	struct regmap *regmap;
	struct irq_domain *irq_domain;
	struct i2c_client *client;
	int client_irq;
	u8 irq_mask;
	u8 old_irq_mask;
	int read_data;
	bool io_error;
	bool done;
	};

	static irqreturn_t cht_wc_i2c_adap_thread_handler(int id, void *data)
	{
	struct cht_wc_i2c_adap *adap = data;
	int ret, reg;

	mutex_lock(&adap->adap_lock);

	/* Read IRQs */
	ret = regmap_read(adap->regmap, CHT_WC_EXTCHGRIRQ, &reg);
	if (ret) {
	dev_err(&adap->adapter.dev, "Error reading extchgrirq reg\n");
	mutex_unlock(&adap->adap_lock);
	return IRQ_NONE;
	}

	reg &= ~adap->irq_mask;

	/* Reads must be acked after reading the received data. */
	ret = regmap_read(adap->regmap, CHT_WC_I2C_RDDATA, &adap->read_data);
	if (ret)
	adap->io_error = true;

	/*
	* Immediately ack IRQs, so that if new IRQs arrives while we're
	* handling the previous ones our irq will re-trigger when we're done.
	*/
	ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ, reg);
	if (ret)
	dev_err(&adap->adapter.dev, "Error writing extchgrirq reg\n");

	if (reg & CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK) {
	adap->io_error \|= !!(reg & CHT_WC_EXTCHGRIRQ_NACK_IRQ);
	adap->done = true;
	}

	mutex_unlock(&adap->adap_lock);

	if (reg & CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK)
	wake_up(&adap->wait);

	/*
	* Do NOT use handle_nested_irq here, the client irq handler will
	* likely want to do i2c transfers and the i2c controller uses this
	* interrupt handler as well, so running the client irq handler from
	* this thread will cause things to lock up.
	*/
	if (reg & CHT_WC_EXTCHGRIRQ_CLIENT_IRQ) {
	/*
	* generic_handle_irq expects local IRQs to be disabled
	* as normally it is called from interrupt context.
	*/
	local_irq_disable();
	generic_handle_irq(adap->client_irq);
	local_irq_enable();
	}

	return IRQ_HANDLED;
	}

	static u32 cht_wc_i2c_adap_master_func(struct i2c_adapter *adap)
	{
	/* This i2c adapter only supports SMBUS byte transfers */
	return I2C_FUNC_SMBUS_BYTE_DATA;
	}

	static int cht_wc_i2c_adap_smbus_xfer(struct i2c_adapter *_adap, u16 addr,
	unsigned short flags, char read_write,
	u8 command, int size,
	union i2c_smbus_data *data)
	{
	struct cht_wc_i2c_adap *adap = i2c_get_adapdata(_adap);
	int ret;

	mutex_lock(&adap->adap_lock);
	adap->io_error = false;
	adap->done = false;
	mutex_unlock(&adap->adap_lock);

	ret = regmap_write(adap->regmap, CHT_WC_I2C_CLIENT_ADDR, addr);
	if (ret)
	return ret;

	if (read_write == I2C_SMBUS_WRITE) {
	ret = regmap_write(adap->regmap, CHT_WC_I2C_WRDATA, data->byte);
	if (ret)
	return ret;
	}

	ret = regmap_write(adap->regmap, CHT_WC_I2C_REG_OFFSET, command);
	if (ret)
	return ret;

	ret = regmap_write(adap->regmap, CHT_WC_I2C_CTRL,
	(read_write == I2C_SMBUS_WRITE) ?
	CHT_WC_I2C_CTRL_WR : CHT_WC_I2C_CTRL_RD);
	if (ret)
	return ret;

	ret = wait_event_timeout(adap->wait, adap->done, msecs_to_jiffies(30));
	if (ret == 0) {
	/*
	* The CHT GPIO controller serializes all IRQs, sometimes
	* causing significant delays, check status manually.
	*/
	cht_wc_i2c_adap_thread_handler(0, adap);
	if (!adap->done)
	return -ETIMEDOUT;
	}

	ret = 0;
	mutex_lock(&adap->adap_lock);
	if (adap->io_error)
	ret = -EIO;
	else if (read_write == I2C_SMBUS_READ)
	data->byte = adap->read_data;
	mutex_unlock(&adap->adap_lock);

	return ret;
	}

	static const struct i2c_algorithm cht_wc_i2c_adap_algo = {
	.functionality = cht_wc_i2c_adap_master_func,
	.smbus_xfer = cht_wc_i2c_adap_smbus_xfer,
	};

	/*
	* We are an i2c-adapter which itself is part of an i2c-client. This means that
	* transfers done through us take adapter->bus_lock twice, once for our parent
	* i2c-adapter and once to take our own bus_lock. Lockdep does not like this
	* nested locking, to make lockdep happy in the case of busses with muxes, the
	* i2c-core's i2c_adapter_lock_bus function calls:
	* rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
	*
	* But i2c_adapter_depth only works when the direct parent of the adapter is
	* another adapter, as it is only meant for muxes. In our case there is an
	* i2c-client and MFD instantiated platform_device in the parent->child chain
	* between the 2 devices.
	*
	* So we override the default i2c_lock_operations and pass a hardcoded
	* depth of 1 to rt_mutex_lock_nested, to make lockdep happy.
	*
	* Note that if there were to be a mux attached to our adapter, this would
	* break things again since the i2c-mux code expects the root-adapter to have
	* a locking depth of 0. But we always have only 1 client directly attached
	* in the form of the Charger IC paired with the CHT Whiskey Cove PMIC.
	*/
	static void cht_wc_i2c_adap_lock_bus(struct i2c_adapter *adapter,
	unsigned int flags)
	{
	rt_mutex_lock_nested(&adapter->bus_lock, 1);
	}

	static int cht_wc_i2c_adap_trylock_bus(struct i2c_adapter *adapter,
	unsigned int flags)
	{
	return rt_mutex_trylock(&adapter->bus_lock);
	}

	static void cht_wc_i2c_adap_unlock_bus(struct i2c_adapter *adapter,
	unsigned int flags)
	{
	rt_mutex_unlock(&adapter->bus_lock);
	}

	static const struct i2c_lock_operations cht_wc_i2c_adap_lock_ops = {
	.lock_bus = cht_wc_i2c_adap_lock_bus,
	.trylock_bus = cht_wc_i2c_adap_trylock_bus,
	.unlock_bus = cht_wc_i2c_adap_unlock_bus,
	};

	/** irqchip for the client connected to the extchgr i2c adapter **/
	static void cht_wc_i2c_irq_lock(struct irq_data *data)
	{
	struct cht_wc_i2c_adap *adap = irq_data_get_irq_chip_data(data);

	mutex_lock(&adap->irqchip_lock);
	}

	static void cht_wc_i2c_irq_sync_unlock(struct irq_data *data)
	{
	struct cht_wc_i2c_adap *adap = irq_data_get_irq_chip_data(data);
	int ret;

	if (adap->irq_mask != adap->old_irq_mask) {
	ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ_MSK,
	adap->irq_mask);
	if (ret == 0)
	adap->old_irq_mask = adap->irq_mask;
	else
	dev_err(&adap->adapter.dev, "Error writing EXTCHGRIRQ_MSK\n");
	}

	mutex_unlock(&adap->irqchip_lock);
	}

	static void cht_wc_i2c_irq_enable(struct irq_data *data)
	{
	struct cht_wc_i2c_adap *adap = irq_data_get_irq_chip_data(data);

	adap->irq_mask &= ~CHT_WC_EXTCHGRIRQ_CLIENT_IRQ;
	}

	static void cht_wc_i2c_irq_disable(struct irq_data *data)
	{
	struct cht_wc_i2c_adap *adap = irq_data_get_irq_chip_data(data);

	adap->irq_mask \|= CHT_WC_EXTCHGRIRQ_CLIENT_IRQ;
	}

	static const struct irq_chip cht_wc_i2c_irq_chip = {
	.irq_bus_lock = cht_wc_i2c_irq_lock,
	.irq_bus_sync_unlock = cht_wc_i2c_irq_sync_unlock,
	.irq_disable = cht_wc_i2c_irq_disable,
	.irq_enable = cht_wc_i2c_irq_enable,
	.name = "cht_wc_ext_chrg_irq_chip",
	};

	static const char * const bq24190_suppliers[] = {
	"tcpm-source-psy-i2c-fusb302" };

	static const struct property_entry bq24190_props[] = {
	PROPERTY_ENTRY_STRING_ARRAY("supplied-from", bq24190_suppliers),
	PROPERTY_ENTRY_BOOL("omit-battery-class"),
	PROPERTY_ENTRY_BOOL("disable-reset"),
	{ }
	};

	static const struct software_node bq24190_node = {
	.properties = bq24190_props,
	};

	static struct regulator_consumer_supply fusb302_consumer = {
	.supply = "vbus",
	/* Must match fusb302 dev_name in intel_cht_int33fe.c */
	.dev_name = "i2c-fusb302",
	};

	static const struct regulator_init_data bq24190_vbus_init_data = {
	.constraints = {
	/* The name is used in intel_cht_int33fe.c do not change. */
	.name = "cht_wc_usb_typec_vbus",
	.valid_ops_mask = REGULATOR_CHANGE_STATUS,
	},
	.consumer_supplies = &fusb302_consumer,
	.num_consumer_supplies = 1,
	};

	static struct bq24190_platform_data bq24190_pdata = {
	.regulator_init_data = &bq24190_vbus_init_data,
	};

	static int cht_wc_i2c_adap_i2c_probe(struct platform_device *pdev)
	{
	struct intel_soc_pmic *pmic = dev_get_drvdata(pdev->dev.parent);
	struct cht_wc_i2c_adap *adap;
	struct i2c_board_info board_info = {
	.type = "bq24190",
	.addr = 0x6b,
	.dev_name = "bq24190",
	.swnode = &bq24190_node,
	.platform_data = &bq24190_pdata,
	};
	int ret, reg, irq;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
	return irq;

	adap = devm_kzalloc(&pdev->dev, sizeof(*adap), GFP_KERNEL);
	if (!adap)
	return -ENOMEM;

	init_waitqueue_head(&adap->wait);
	mutex_init(&adap->adap_lock);
	mutex_init(&adap->irqchip_lock);
	adap->irqchip = cht_wc_i2c_irq_chip;
	adap->regmap = pmic->regmap;
	adap->adapter.owner = THIS_MODULE;
	adap->adapter.class = I2C_CLASS_HWMON;
	adap->adapter.algo = &cht_wc_i2c_adap_algo;
	adap->adapter.lock_ops = &cht_wc_i2c_adap_lock_ops;
	strlcpy(adap->adapter.name, "PMIC I2C Adapter",
	sizeof(adap->adapter.name));
	adap->adapter.dev.parent = &pdev->dev;

	/* Clear and activate i2c-adapter interrupts, disable client IRQ */
	adap->old_irq_mask = adap->irq_mask = ~CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK;

	ret = regmap_read(adap->regmap, CHT_WC_I2C_RDDATA, &reg);
	if (ret)
	return ret;

	ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ, ~adap->irq_mask);
	if (ret)
	return ret;

	ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ_MSK, adap->irq_mask);
	if (ret)
	return ret;

	/* Alloc and register client IRQ */
	adap->irq_domain = irq_domain_add_linear(NULL, 1, &irq_domain_simple_ops, NULL);
	if (!adap->irq_domain)
	return -ENOMEM;

	adap->client_irq = irq_create_mapping(adap->irq_domain, 0);
	if (!adap->client_irq) {
	ret = -ENOMEM;
	goto remove_irq_domain;
	}

	irq_set_chip_data(adap->client_irq, adap);
	irq_set_chip_and_handler(adap->client_irq, &adap->irqchip,
	handle_simple_irq);

	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
	cht_wc_i2c_adap_thread_handler,
	IRQF_ONESHOT, "PMIC I2C Adapter", adap);
	if (ret)
	goto remove_irq_domain;

	i2c_set_adapdata(&adap->adapter, adap);
	ret = i2c_add_adapter(&adap->adapter);
	if (ret)
	goto remove_irq_domain;

	/*
	* Normally the Whiskey Cove PMIC is paired with a TI bq24292i charger,
	* connected to this i2c bus, and a max17047 fuel-gauge and a fusb302
	* USB Type-C controller connected to another i2c bus. In this setup
	* the max17047 and fusb302 devices are enumerated through an INT33FE
	* ACPI device. If this device is present register an i2c-client for
	* the TI bq24292i charger.
	*/
	if (acpi_dev_present("INT33FE", NULL, -1)) {
	board_info.irq = adap->client_irq;
	adap->client = i2c_new_client_device(&adap->adapter, &board_info);
	if (IS_ERR(adap->client)) {
	ret = PTR_ERR(adap->client);
	goto del_adapter;
	}
	}

	platform_set_drvdata(pdev, adap);
	return 0;

	del_adapter:
	i2c_del_adapter(&adap->adapter);
	remove_irq_domain:
	irq_domain_remove(adap->irq_domain);
	return ret;
	}

	static int cht_wc_i2c_adap_i2c_remove(struct platform_device *pdev)
	{
	struct cht_wc_i2c_adap *adap = platform_get_drvdata(pdev);

	i2c_unregister_device(adap->client);
	i2c_del_adapter(&adap->adapter);
	irq_domain_remove(adap->irq_domain);

	return 0;
	}

	static const struct platform_device_id cht_wc_i2c_adap_id_table[] = {
	{ .name = "cht_wcove_ext_chgr" },
	{},
	};
	MODULE_DEVICE_TABLE(platform, cht_wc_i2c_adap_id_table);

	static struct platform_driver cht_wc_i2c_adap_driver = {
	.probe = cht_wc_i2c_adap_i2c_probe,
	.remove = cht_wc_i2c_adap_i2c_remove,
	.driver = {
	.name = "cht_wcove_ext_chgr",
	},
	.id_table = cht_wc_i2c_adap_id_table,
	};
	module_platform_driver(cht_wc_i2c_adap_driver);

	MODULE_DESCRIPTION("Intel CHT Whiskey Cove PMIC I2C Master driver");
	MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
	MODULE_LICENSE("GPL");