drivers/i2c/muxes/i2c-mux-pca954x.c - arm/linux - Git at Google

 /*
  * I2C multiplexer
  *
  * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
  * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
  *
  * This module supports the PCA954x series of I2C multiplexer/switch chips
  * made by Philips Semiconductors.
  * This includes the:
  *	 PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547
  *	 and PCA9548.
  *
  * These chips are all controlled via the I2C bus itself, and all have a
  * single 8-bit register. The upstream "parent" bus fans out to two,
  * four, or eight downstream busses or channels; which of these
  * are selected is determined by the chip type and register contents. A
  * mux can select only one sub-bus at a time; a switch can select any
  * combination simultaneously.
  *
  * Based on:
  *	pca954x.c from Kumar Gala <galak@kernel.crashing.org>
  * Copyright (C) 2006
  *
  * Based on:
  *	pca954x.c from Ken Harrenstien
  * Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
  *
  * Based on:
  *	i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
  * and
  *	pca9540.c from Jean Delvare <jdelvare@suse.de>.
  *
  * This file is licensed under the terms of the GNU General Public
  * License version 2. This program is licensed "as is" without any
  * warranty of any kind, whether express or implied.
  */

 #include <linux/device.h>
 #include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/i2c-mux.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/of_irq.h>
 #include <linux/platform_data/pca954x.h>
 #include <linux/pm.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>

 #define PCA954X_MAX_NCHANS 8

 #define PCA954X_IRQ_OFFSET 4

 enum pca_type {
 	pca_9540,
 	pca_9542,
 	pca_9543,
 	pca_9544,
 	pca_9545,
 	pca_9546,
 	pca_9547,
 	pca_9548,
 };

 struct chip_desc {
 	u8 nchans;
 	u8 enable;	/* used for muxes only */
 	u8 has_irq;
 	enum muxtype {
 		pca954x_ismux = 0,
 		pca954x_isswi
 	} muxtype;
 };

 struct pca954x {
 	const struct chip_desc *chip;

 	u8 last_chan;		/* last register value */
 	u8 deselect;
 	struct i2c_client *client;

 	struct irq_domain *irq;
 	unsigned int irq_mask;
 	raw_spinlock_t lock;
 };

 /* Provide specs for the PCA954x types we know about */
 static const struct chip_desc chips[] = {
 	[pca_9540] = {
 		.nchans = 2,
 		.enable = 0x4,
 		.muxtype = pca954x_ismux,
 	},
 	[pca_9542] = {
 		.nchans = 2,
 		.enable = 0x4,
 		.has_irq = 1,
 		.muxtype = pca954x_ismux,
 	},
 	[pca_9543] = {
 		.nchans = 2,
 		.has_irq = 1,
 		.muxtype = pca954x_isswi,
 	},
 	[pca_9544] = {
 		.nchans = 4,
 		.enable = 0x4,
 		.has_irq = 1,
 		.muxtype = pca954x_ismux,
 	},
 	[pca_9545] = {
 		.nchans = 4,
 		.has_irq = 1,
 		.muxtype = pca954x_isswi,
 	},
 	[pca_9546] = {
 		.nchans = 4,
 		.muxtype = pca954x_isswi,
 	},
 	[pca_9547] = {
 		.nchans = 8,
 		.enable = 0x8,
 		.muxtype = pca954x_ismux,
 	},
 	[pca_9548] = {
 		.nchans = 8,
 		.muxtype = pca954x_isswi,
 	},
 };

 static const struct i2c_device_id pca954x_id[] = {
 	{ "pca9540", pca_9540 },
 	{ "pca9542", pca_9542 },
 	{ "pca9543", pca_9543 },
 	{ "pca9544", pca_9544 },
 	{ "pca9545", pca_9545 },
 	{ "pca9546", pca_9546 },
 	{ "pca9547", pca_9547 },
 	{ "pca9548", pca_9548 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, pca954x_id);

 #ifdef CONFIG_OF
 static const struct of_device_id pca954x_of_match[] = {
 	{ .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
 	{ .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
 	{ .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
 	{ .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
 	{ .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
 	{ .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
 	{ .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
 	{ .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
 	{}
 };
 MODULE_DEVICE_TABLE(of, pca954x_of_match);
 #endif

 /* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
    for this as they will try to lock adapter a second time */
 static int pca954x_reg_write(struct i2c_adapter *adap,
 			     struct i2c_client *client, u8 val)
 {
 	int ret = -ENODEV;

 	if (adap->algo->master_xfer) {
 		struct i2c_msg msg;
 		char buf[1];

 		msg.addr = client->addr;
 		msg.flags = 0;
 		msg.len = 1;
 		buf[0] = val;
 		msg.buf = buf;
 		ret = __i2c_transfer(adap, &msg, 1);

 		if (ret >= 0 && ret != 1)
 			ret = -EREMOTEIO;
 	} else {
 		union i2c_smbus_data data;
 		ret = adap->algo->smbus_xfer(adap, client->addr,
 					     client->flags,
 					     I2C_SMBUS_WRITE,
 					     val, I2C_SMBUS_BYTE, &data);
 	}

 	return ret;
 }

 static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
 {
 	struct pca954x *data = i2c_mux_priv(muxc);
 	struct i2c_client *client = data->client;
 	const struct chip_desc *chip = data->chip;
 	u8 regval;
 	int ret = 0;

 	/* we make switches look like muxes, not sure how to be smarter */
 	if (chip->muxtype == pca954x_ismux)
 		regval = chan | chip->enable;
 	else
 		regval = 1 << chan;

 	/* Only select the channel if its different from the last channel */
 	if (data->last_chan != regval) {
 		ret = pca954x_reg_write(muxc->parent, client, regval);
 		data->last_chan = ret < 0 ? 0 : regval;
 	}

 	return ret;
 }

 static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
 {
 	struct pca954x *data = i2c_mux_priv(muxc);
 	struct i2c_client *client = data->client;

 	if (!(data->deselect & (1 << chan)))
 		return 0;

 	/* Deselect active channel */
 	data->last_chan = 0;
 	return pca954x_reg_write(muxc->parent, client, data->last_chan);
 }

 static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
 {
 	struct pca954x *data = dev_id;
 	unsigned int child_irq;
 	int ret, i, handled = 0;

 	ret = i2c_smbus_read_byte(data->client);
 	if (ret < 0)
 		return IRQ_NONE;

 	for (i = 0; i < data->chip->nchans; i++) {
 		if (ret & BIT(PCA954X_IRQ_OFFSET + i)) {
 			child_irq = irq_linear_revmap(data->irq, i);
 			handle_nested_irq(child_irq);
 			handled++;
 		}
 	}
 	return handled ? IRQ_HANDLED : IRQ_NONE;
 }

 static void pca954x_irq_mask(struct irq_data *idata)
 {
 	struct pca954x *data = irq_data_get_irq_chip_data(idata);
 	unsigned int pos = idata->hwirq;
 	unsigned long flags;

 	raw_spin_lock_irqsave(&data->lock, flags);

 	data->irq_mask &= ~BIT(pos);
 	if (!data->irq_mask)
 		disable_irq(data->client->irq);

 	raw_spin_unlock_irqrestore(&data->lock, flags);
 }

 static void pca954x_irq_unmask(struct irq_data *idata)
 {
 	struct pca954x *data = irq_data_get_irq_chip_data(idata);
 	unsigned int pos = idata->hwirq;
 	unsigned long flags;

 	raw_spin_lock_irqsave(&data->lock, flags);

 	if (!data->irq_mask)
 		enable_irq(data->client->irq);
 	data->irq_mask |= BIT(pos);

 	raw_spin_unlock_irqrestore(&data->lock, flags);
 }

 static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
 {
 	if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
 		return -EINVAL;
 	return 0;
 }

 static struct irq_chip pca954x_irq_chip = {
 	.name = "i2c-mux-pca954x",
 	.irq_mask = pca954x_irq_mask,
 	.irq_unmask = pca954x_irq_unmask,
 	.irq_set_type = pca954x_irq_set_type,
 };

 static int pca954x_irq_setup(struct i2c_mux_core *muxc)
 {
 	struct pca954x *data = i2c_mux_priv(muxc);
 	struct i2c_client *client = data->client;
 	int c, err, irq;

 	if (!data->chip->has_irq || client->irq <= 0)
 		return 0;

 	raw_spin_lock_init(&data->lock);

 	data->irq = irq_domain_add_linear(client->dev.of_node,
 					  data->chip->nchans,
 					  &irq_domain_simple_ops, data);
 	if (!data->irq)
 		return -ENODEV;

 	for (c = 0; c < data->chip->nchans; c++) {
 		irq = irq_create_mapping(data->irq, c);
 		irq_set_chip_data(irq, data);
 		irq_set_chip_and_handler(irq, &pca954x_irq_chip,
 			handle_simple_irq);
 	}

 	err = devm_request_threaded_irq(&client->dev, data->client->irq, NULL,
 					pca954x_irq_handler,
 					IRQF_ONESHOT | IRQF_SHARED,
 					"pca954x", data);
 	if (err)
 		goto err_req_irq;

 	disable_irq(data->client->irq);

 	return 0;
 err_req_irq:
 	for (c = 0; c < data->chip->nchans; c++) {
 		irq = irq_find_mapping(data->irq, c);
 		irq_dispose_mapping(irq);
 	}
 	irq_domain_remove(data->irq);

 	return err;
 }

 /*
  * I2C init/probing/exit functions
  */
 static int pca954x_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
 	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
 	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
 	struct device_node *of_node = client->dev.of_node;
 	bool idle_disconnect_dt;
 	struct gpio_desc *gpio;
 	int num, force, class;
 	struct i2c_mux_core *muxc;
 	struct pca954x *data;
 	const struct of_device_id *match;
 	int ret;

 	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
 		return -ENODEV;

 	muxc = i2c_mux_alloc(adap, &client->dev,
 			     PCA954X_MAX_NCHANS, sizeof(*data), 0,
 			     pca954x_select_chan, pca954x_deselect_mux);
 	if (!muxc)
 		return -ENOMEM;
 	data = i2c_mux_priv(muxc);

 	i2c_set_clientdata(client, muxc);
 	data->client = client;

 	/* Get the mux out of reset if a reset GPIO is specified. */
 	gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW);
 	if (IS_ERR(gpio))
 		return PTR_ERR(gpio);

 	/* Write the mux register at addr to verify
 	 * that the mux is in fact present. This also
 	 * initializes the mux to disconnected state.
 	 */
 	if (i2c_smbus_write_byte(client, 0) < 0) {
 		dev_warn(&client->dev, "probe failed\n");
 		return -ENODEV;
 	}

 	match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev);
 	if (match)
 		data->chip = of_device_get_match_data(&client->dev);
 	else
 		data->chip = &chips[id->driver_data];

 	data->last_chan = 0;		   /* force the first selection */

 	idle_disconnect_dt = of_node &&
 		of_property_read_bool(of_node, "i2c-mux-idle-disconnect");

 	ret = pca954x_irq_setup(muxc);
 	if (ret)
 		goto fail_del_adapters;

 	/* Now create an adapter for each channel */
 	for (num = 0; num < data->chip->nchans; num++) {
 		bool idle_disconnect_pd = false;

 		force = 0;			  /* dynamic adap number */
 		class = 0;			  /* no class by default */
 		if (pdata) {
 			if (num < pdata->num_modes) {
 				/* force static number */
 				force = pdata->modes[num].adap_id;
 				class = pdata->modes[num].class;
 			} else
 				/* discard unconfigured channels */
 				break;
 			idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
 		}
 		data->deselect |= (idle_disconnect_pd ||
 				   idle_disconnect_dt) << num;

 		ret = i2c_mux_add_adapter(muxc, force, num, class);
 		if (ret)
 			goto fail_del_adapters;
 	}

 	dev_info(&client->dev,
 		 "registered %d multiplexed busses for I2C %s %s\n",
 		 num, data->chip->muxtype == pca954x_ismux
 				? "mux" : "switch", client->name);

 	return 0;

 fail_del_adapters:
 	i2c_mux_del_adapters(muxc);
 	return ret;
 }

 static int pca954x_remove(struct i2c_client *client)
 {
 	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 	struct pca954x *data = i2c_mux_priv(muxc);
 	int c, irq;

 	if (data->irq) {
 		for (c = 0; c < data->chip->nchans; c++) {
 			irq = irq_find_mapping(data->irq, c);
 			irq_dispose_mapping(irq);
 		}
 		irq_domain_remove(data->irq);
 	}

 	i2c_mux_del_adapters(muxc);
 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP
 static int pca954x_resume(struct device *dev)
 {
 	struct i2c_client *client = to_i2c_client(dev);
 	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
 	struct pca954x *data = i2c_mux_priv(muxc);

 	data->last_chan = 0;
 	return i2c_smbus_write_byte(client, 0);
 }
 #endif

 static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);

 static struct i2c_driver pca954x_driver = {
 	.driver		= {
 		.name	= "pca954x",
 		.pm	= &pca954x_pm,
 		.of_match_table = of_match_ptr(pca954x_of_match),
 	},
 	.probe		= pca954x_probe,
 	.remove		= pca954x_remove,
 	.id_table	= pca954x_id,
 };

 module_i2c_driver(pca954x_driver);

 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
 MODULE_LICENSE("GPL v2");
	/*
	* I2C multiplexer
	*
	* Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
	* Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
	*
	* This module supports the PCA954x series of I2C multiplexer/switch chips
	* made by Philips Semiconductors.
	* This includes the:
	* PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547
	* and PCA9548.
	*
	* These chips are all controlled via the I2C bus itself, and all have a
	* single 8-bit register. The upstream "parent" bus fans out to two,
	* four, or eight downstream busses or channels; which of these
	* are selected is determined by the chip type and register contents. A
	* mux can select only one sub-bus at a time; a switch can select any
	* combination simultaneously.
	*
	* Based on:
	* pca954x.c from Kumar Gala <galak@kernel.crashing.org>
	* Copyright (C) 2006
	*
	* Based on:
	* pca954x.c from Ken Harrenstien
	* Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
	*
	* Based on:
	* i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
	* and
	* pca9540.c from Jean Delvare <jdelvare@suse.de>.
	*
	* This file is licensed under the terms of the GNU General Public
	* License version 2. This program is licensed "as is" without any
	* warranty of any kind, whether express or implied.
	*/

	#include <linux/device.h>
	#include <linux/gpio/consumer.h>
	#include <linux/i2c.h>
	#include <linux/i2c-mux.h>
	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/of_irq.h>
	#include <linux/platform_data/pca954x.h>
	#include <linux/pm.h>
	#include <linux/slab.h>
	#include <linux/spinlock.h>

	#define PCA954X_MAX_NCHANS 8

	#define PCA954X_IRQ_OFFSET 4

	enum pca_type {
	pca_9540,
	pca_9542,
	pca_9543,
	pca_9544,
	pca_9545,
	pca_9546,
	pca_9547,
	pca_9548,
	};

	struct chip_desc {
	u8 nchans;
	u8 enable; /* used for muxes only */
	u8 has_irq;
	enum muxtype {
	pca954x_ismux = 0,
	pca954x_isswi
	} muxtype;
	};

	struct pca954x {
	const struct chip_desc *chip;

	u8 last_chan; /* last register value */
	u8 deselect;
	struct i2c_client *client;

	struct irq_domain *irq;
	unsigned int irq_mask;
	raw_spinlock_t lock;
	};

	/* Provide specs for the PCA954x types we know about */
	static const struct chip_desc chips[] = {
	[pca_9540] = {
	.nchans = 2,
	.enable = 0x4,
	.muxtype = pca954x_ismux,
	},
	[pca_9542] = {
	.nchans = 2,
	.enable = 0x4,
	.has_irq = 1,
	.muxtype = pca954x_ismux,
	},
	[pca_9543] = {
	.nchans = 2,
	.has_irq = 1,
	.muxtype = pca954x_isswi,
	},
	[pca_9544] = {
	.nchans = 4,
	.enable = 0x4,
	.has_irq = 1,
	.muxtype = pca954x_ismux,
	},
	[pca_9545] = {
	.nchans = 4,
	.has_irq = 1,
	.muxtype = pca954x_isswi,
	},
	[pca_9546] = {
	.nchans = 4,
	.muxtype = pca954x_isswi,
	},
	[pca_9547] = {
	.nchans = 8,
	.enable = 0x8,
	.muxtype = pca954x_ismux,
	},
	[pca_9548] = {
	.nchans = 8,
	.muxtype = pca954x_isswi,
	},
	};

	static const struct i2c_device_id pca954x_id[] = {
	{ "pca9540", pca_9540 },
	{ "pca9542", pca_9542 },
	{ "pca9543", pca_9543 },
	{ "pca9544", pca_9544 },
	{ "pca9545", pca_9545 },
	{ "pca9546", pca_9546 },
	{ "pca9547", pca_9547 },
	{ "pca9548", pca_9548 },
	{ }
	};
	MODULE_DEVICE_TABLE(i2c, pca954x_id);

	#ifdef CONFIG_OF
	static const struct of_device_id pca954x_of_match[] = {
	{ .compatible = "nxp,pca9540", .data = &chips[pca_9540] },
	{ .compatible = "nxp,pca9542", .data = &chips[pca_9542] },
	{ .compatible = "nxp,pca9543", .data = &chips[pca_9543] },
	{ .compatible = "nxp,pca9544", .data = &chips[pca_9544] },
	{ .compatible = "nxp,pca9545", .data = &chips[pca_9545] },
	{ .compatible = "nxp,pca9546", .data = &chips[pca_9546] },
	{ .compatible = "nxp,pca9547", .data = &chips[pca_9547] },
	{ .compatible = "nxp,pca9548", .data = &chips[pca_9548] },
	{}
	};
	MODULE_DEVICE_TABLE(of, pca954x_of_match);
	#endif

	/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
	for this as they will try to lock adapter a second time */
	static int pca954x_reg_write(struct i2c_adapter *adap,
	struct i2c_client *client, u8 val)
	{
	int ret = -ENODEV;

	if (adap->algo->master_xfer) {
	struct i2c_msg msg;
	char buf[1];

	msg.addr = client->addr;
	msg.flags = 0;
	msg.len = 1;
	buf[0] = val;
	msg.buf = buf;
	ret = __i2c_transfer(adap, &msg, 1);

	if (ret >= 0 && ret != 1)
	ret = -EREMOTEIO;
	} else {
	union i2c_smbus_data data;
	ret = adap->algo->smbus_xfer(adap, client->addr,
	client->flags,
	I2C_SMBUS_WRITE,
	val, I2C_SMBUS_BYTE, &data);
	}

	return ret;
	}

	static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
	{
	struct pca954x *data = i2c_mux_priv(muxc);
	struct i2c_client *client = data->client;
	const struct chip_desc *chip = data->chip;
	u8 regval;
	int ret = 0;

	/* we make switches look like muxes, not sure how to be smarter */
	if (chip->muxtype == pca954x_ismux)
	regval = chan \| chip->enable;
	else
	regval = 1 << chan;

	/* Only select the channel if its different from the last channel */
	if (data->last_chan != regval) {
	ret = pca954x_reg_write(muxc->parent, client, regval);
	data->last_chan = ret < 0 ? 0 : regval;
	}

	return ret;
	}

	static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
	{
	struct pca954x *data = i2c_mux_priv(muxc);
	struct i2c_client *client = data->client;

	if (!(data->deselect & (1 << chan)))
	return 0;

	/* Deselect active channel */
	data->last_chan = 0;
	return pca954x_reg_write(muxc->parent, client, data->last_chan);
	}

	static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
	{
	struct pca954x *data = dev_id;
	unsigned int child_irq;
	int ret, i, handled = 0;

	ret = i2c_smbus_read_byte(data->client);
	if (ret < 0)
	return IRQ_NONE;

	for (i = 0; i < data->chip->nchans; i++) {
	if (ret & BIT(PCA954X_IRQ_OFFSET + i)) {
	child_irq = irq_linear_revmap(data->irq, i);
	handle_nested_irq(child_irq);
	handled++;
	}
	}
	return handled ? IRQ_HANDLED : IRQ_NONE;
	}

	static void pca954x_irq_mask(struct irq_data *idata)
	{
	struct pca954x *data = irq_data_get_irq_chip_data(idata);
	unsigned int pos = idata->hwirq;
	unsigned long flags;

	raw_spin_lock_irqsave(&data->lock, flags);

	data->irq_mask &= ~BIT(pos);
	if (!data->irq_mask)
	disable_irq(data->client->irq);

	raw_spin_unlock_irqrestore(&data->lock, flags);
	}

	static void pca954x_irq_unmask(struct irq_data *idata)
	{
	struct pca954x *data = irq_data_get_irq_chip_data(idata);
	unsigned int pos = idata->hwirq;
	unsigned long flags;

	raw_spin_lock_irqsave(&data->lock, flags);

	if (!data->irq_mask)
	enable_irq(data->client->irq);
	data->irq_mask \|= BIT(pos);

	raw_spin_unlock_irqrestore(&data->lock, flags);
	}

	static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
	{
	if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
	return -EINVAL;
	return 0;
	}

	static struct irq_chip pca954x_irq_chip = {
	.name = "i2c-mux-pca954x",
	.irq_mask = pca954x_irq_mask,
	.irq_unmask = pca954x_irq_unmask,
	.irq_set_type = pca954x_irq_set_type,
	};

	static int pca954x_irq_setup(struct i2c_mux_core *muxc)
	{
	struct pca954x *data = i2c_mux_priv(muxc);
	struct i2c_client *client = data->client;
	int c, err, irq;

	if (!data->chip->has_irq \|\| client->irq <= 0)
	return 0;

	raw_spin_lock_init(&data->lock);

	data->irq = irq_domain_add_linear(client->dev.of_node,
	data->chip->nchans,
	&irq_domain_simple_ops, data);
	if (!data->irq)
	return -ENODEV;

	for (c = 0; c < data->chip->nchans; c++) {
	irq = irq_create_mapping(data->irq, c);
	irq_set_chip_data(irq, data);
	irq_set_chip_and_handler(irq, &pca954x_irq_chip,
	handle_simple_irq);
	}

	err = devm_request_threaded_irq(&client->dev, data->client->irq, NULL,
	pca954x_irq_handler,
	IRQF_ONESHOT \| IRQF_SHARED,
	"pca954x", data);
	if (err)
	goto err_req_irq;

	disable_irq(data->client->irq);

	return 0;
	err_req_irq:
	for (c = 0; c < data->chip->nchans; c++) {
	irq = irq_find_mapping(data->irq, c);
	irq_dispose_mapping(irq);
	}
	irq_domain_remove(data->irq);

	return err;
	}

	/*
	* I2C init/probing/exit functions
	*/
	static int pca954x_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
	struct device_node *of_node = client->dev.of_node;
	bool idle_disconnect_dt;
	struct gpio_desc *gpio;
	int num, force, class;
	struct i2c_mux_core *muxc;
	struct pca954x *data;
	const struct of_device_id *match;
	int ret;

	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
	return -ENODEV;

	muxc = i2c_mux_alloc(adap, &client->dev,
	PCA954X_MAX_NCHANS, sizeof(*data), 0,
	pca954x_select_chan, pca954x_deselect_mux);
	if (!muxc)
	return -ENOMEM;
	data = i2c_mux_priv(muxc);

	i2c_set_clientdata(client, muxc);
	data->client = client;

	/* Get the mux out of reset if a reset GPIO is specified. */
	gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW);
	if (IS_ERR(gpio))
	return PTR_ERR(gpio);

	/* Write the mux register at addr to verify
	* that the mux is in fact present. This also
	* initializes the mux to disconnected state.
	*/
	if (i2c_smbus_write_byte(client, 0) < 0) {
	dev_warn(&client->dev, "probe failed\n");
	return -ENODEV;
	}

	match = of_match_device(of_match_ptr(pca954x_of_match), &client->dev);
	if (match)
	data->chip = of_device_get_match_data(&client->dev);
	else
	data->chip = &chips[id->driver_data];

	data->last_chan = 0; /* force the first selection */

	idle_disconnect_dt = of_node &&
	of_property_read_bool(of_node, "i2c-mux-idle-disconnect");

	ret = pca954x_irq_setup(muxc);
	if (ret)
	goto fail_del_adapters;

	/* Now create an adapter for each channel */
	for (num = 0; num < data->chip->nchans; num++) {
	bool idle_disconnect_pd = false;

	force = 0; /* dynamic adap number */
	class = 0; /* no class by default */
	if (pdata) {
	if (num < pdata->num_modes) {
	/* force static number */
	force = pdata->modes[num].adap_id;
	class = pdata->modes[num].class;
	} else
	/* discard unconfigured channels */
	break;
	idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
	}
	data->deselect \|= (idle_disconnect_pd \|\|
	idle_disconnect_dt) << num;

	ret = i2c_mux_add_adapter(muxc, force, num, class);
	if (ret)
	goto fail_del_adapters;
	}

	dev_info(&client->dev,
	"registered %d multiplexed busses for I2C %s %s\n",
	num, data->chip->muxtype == pca954x_ismux
	? "mux" : "switch", client->name);

	return 0;

	fail_del_adapters:
	i2c_mux_del_adapters(muxc);
	return ret;
	}

	static int pca954x_remove(struct i2c_client *client)
	{
	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
	struct pca954x *data = i2c_mux_priv(muxc);
	int c, irq;

	if (data->irq) {
	for (c = 0; c < data->chip->nchans; c++) {
	irq = irq_find_mapping(data->irq, c);
	irq_dispose_mapping(irq);
	}
	irq_domain_remove(data->irq);
	}

	i2c_mux_del_adapters(muxc);
	return 0;
	}

	#ifdef CONFIG_PM_SLEEP
	static int pca954x_resume(struct device *dev)
	{
	struct i2c_client *client = to_i2c_client(dev);
	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
	struct pca954x *data = i2c_mux_priv(muxc);

	data->last_chan = 0;
	return i2c_smbus_write_byte(client, 0);
	}
	#endif

	static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);

	static struct i2c_driver pca954x_driver = {
	.driver = {
	.name = "pca954x",
	.pm = &pca954x_pm,
	.of_match_table = of_match_ptr(pca954x_of_match),
	},
	.probe = pca954x_probe,
	.remove = pca954x_remove,
	.id_table = pca954x_id,
	};

	module_i2c_driver(pca954x_driver);

	MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
	MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
	MODULE_LICENSE("GPL v2");