[mirror_ubuntu-zesty-kernel.git] / drivers / i2c / muxes / i2c-mux-pca954x.c

/*
 * 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/i2c/pca954x.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pm.h>
#include <linux/slab.h>

#define PCA954X_MAX_NCHANS 8

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

struct pca954x {
	enum pca_type type;

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

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

/* 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_9543] = {
		.nchans = 2,
		.muxtype = pca954x_isswi,
	},
	[pca_9544] = {
		.nchans = 4,
		.enable = 0x4,
		.muxtype = pca954x_ismux,
	},
	[pca_9545] = {
		.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_9540 },
	{ "pca9543", pca_9543 },
	{ "pca9544", pca_9544 },
	{ "pca9545", pca_9545 },
	{ "pca9546", pca_9545 },
	{ "pca9547", pca_9547 },
	{ "pca9548", pca_9548 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, pca954x_id);

/* 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);
	} 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 = &chips[data->type];
	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 : 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);
}

/*
 * 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;
	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;
	}

	data->type = 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");

	/* Now create an adapter for each channel */
	for (num = 0; num < chips[data->type].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) {
			dev_err(&client->dev,
				"failed to register multiplexed adapter"
				" %d as bus %d\n", num, force);
			goto virt_reg_failed;
		}
	}

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

	return 0;

virt_reg_failed:
	i2c_mux_del_adapters(muxc);
	return ret;
}

static int pca954x_remove(struct i2c_client *client)
{
	struct i2c_mux_core *muxc = i2c_get_clientdata(client);

	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,
	},
	.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");
Commit	Line	Data
7f528135 ML	1	/*
	2	* I2C multiplexer
	3	*
	4	* Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
	5	* Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
	6	*
	7	* This module supports the PCA954x series of I2C multiplexer/switch chips
	8	* made by Philips Semiconductors.
	9	* This includes the:
	10	* PCA9540, PCA9542, PCA9543, PCA9544, PCA9545, PCA9546, PCA9547
	11	* and PCA9548.
	12	*
	13	* These chips are all controlled via the I2C bus itself, and all have a
	14	* single 8-bit register. The upstream "parent" bus fans out to two,
	15	* four, or eight downstream busses or channels; which of these
	16	* are selected is determined by the chip type and register contents. A
	17	* mux can select only one sub-bus at a time; a switch can select any
	18	* combination simultaneously.
	19	*
	20	* Based on:
	21	* pca954x.c from Kumar Gala <galak@kernel.crashing.org>
	22	* Copyright (C) 2006
	23	*
	24	* Based on:
	25	* pca954x.c from Ken Harrenstien
	26	* Copyright (C) 2004 Google, Inc. (Ken Harrenstien)
	27	*
	28	* Based on:
	29	* i2c-virtual_cb.c from Brian Kuschak <bkuschak@yahoo.com>
	30	* and
7c81c60f	31	* pca9540.c from Jean Delvare <jdelvare@suse.de>.
7f528135 ML	32	*
	33	* This file is licensed under the terms of the GNU General Public
	34	* License version 2. This program is licensed "as is" without any
	35	* warranty of any kind, whether express or implied.
	36	*/
	37
7f528135	38	#include <linux/device.h>
642653d1	39	#include <linux/gpio/consumer.h>
7f528135 ML	40	#include <linux/i2c.h>
7f528135 ML	41	#include <linux/i2c-mux.h>
7f528135	42	#include <linux/i2c/pca954x.h>
4b9b0073	43	#include <linux/module.h>
72f02715	44	#include <linux/of.h>
f5e596cd	45	#include <linux/pm.h>
4b9b0073	46	#include <linux/slab.h>
7f528135 ML	47
	48	#define PCA954X_MAX_NCHANS 8
	49
	50	enum pca_type {
	51	pca_9540,
	52	pca_9542,
	53	pca_9543,
	54	pca_9544,
	55	pca_9545,
	56	pca_9546,
	57	pca_9547,
	58	pca_9548,
	59	};
	60
	61	struct pca954x {
	62	enum pca_type type;
7f528135 ML	63
7f528135 ML	64	u8 last_chan; /* last register value */
7fcac980 PR	65	u8 deselect;
7fcac980 PR	66	struct i2c_client *client;
7f528135 ML	67	};
	68
	69	struct chip_desc {
	70	u8 nchans;
	71	u8 enable; /* used for muxes only */
	72	enum muxtype {
	73	pca954x_ismux = 0,
	74	pca954x_isswi
	75	} muxtype;
	76	};
	77
	78	/* Provide specs for the PCA954x types we know about */
	79	static const struct chip_desc chips[] = {
	80	[pca_9540] = {
	81	.nchans = 2,
	82	.enable = 0x4,
	83	.muxtype = pca954x_ismux,
	84	},
	85	[pca_9543] = {
	86	.nchans = 2,
	87	.muxtype = pca954x_isswi,
	88	},
	89	[pca_9544] = {
	90	.nchans = 4,
	91	.enable = 0x4,
	92	.muxtype = pca954x_ismux,
	93	},
	94	[pca_9545] = {
	95	.nchans = 4,
	96	.muxtype = pca954x_isswi,
	97	},
	98	[pca_9547] = {
	99	.nchans = 8,
	100	.enable = 0x8,
	101	.muxtype = pca954x_ismux,
	102	},
	103	[pca_9548] = {
	104	.nchans = 8,
	105	.muxtype = pca954x_isswi,
	106	},
	107	};
	108
	109	static const struct i2c_device_id pca954x_id[] = {
	110	{ "pca9540", pca_9540 },
	111	{ "pca9542", pca_9540 },
	112	{ "pca9543", pca_9543 },
	113	{ "pca9544", pca_9544 },
	114	{ "pca9545", pca_9545 },
	115	{ "pca9546", pca_9545 },
	116	{ "pca9547", pca_9547 },
	117	{ "pca9548", pca_9548 },
	118	{ }
	119	};
	120	MODULE_DEVICE_TABLE(i2c, pca954x_id);
	121
	122	/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
	123	for this as they will try to lock adapter a second time */
	124	static int pca954x_reg_write(struct i2c_adapter *adap,
	125	struct i2c_client *client, u8 val)
	126	{
	127	int ret = -ENODEV;
	128
	129	if (adap->algo->master_xfer) {
	130	struct i2c_msg msg;
131	char buf[1];
132
133	msg.addr = client->addr;
134	msg.flags = 0;
135	msg.len = 1;
136	buf[0] = val;
137	msg.buf = buf;
0a8237ae	138	ret = __i2c_transfer(adap, &msg, 1);
7f528135 ML	139	} else {
	140	union i2c_smbus_data data;
	141	ret = adap->algo->smbus_xfer(adap, client->addr,
	142	client->flags,
	143	I2C_SMBUS_WRITE,
	144	val, I2C_SMBUS_BYTE, &data);
	145	}
	146
	147	return ret;
	148	}
	149
7fcac980	150	static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan)
7f528135	151	{
7fcac980 PR	152	struct pca954x *data = i2c_mux_priv(muxc);
7fcac980 PR	153	struct i2c_client *client = data->client;
7f528135 ML	154	const struct chip_desc *chip = &chips[data->type];
	155	u8 regval;
	156	int ret = 0;
	157
	158	/* we make switches look like muxes, not sure how to be smarter */
	159	if (chip->muxtype == pca954x_ismux)
	160	regval = chan \| chip->enable;
	161	else
	162	regval = 1 << chan;
	163
	164	/* Only select the channel if its different from the last channel */
	165	if (data->last_chan != regval) {
7fcac980	166	ret = pca954x_reg_write(muxc->parent, client, regval);
463e8f84	167	data->last_chan = ret ? 0 : regval;
7f528135 ML	168	}
	169
	170	return ret;
	171	}
	172
7fcac980	173	static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
7f528135	174	{
7fcac980 PR	175	struct pca954x *data = i2c_mux_priv(muxc);
	176	struct i2c_client *client = data->client;
	177
	178	if (!(data->deselect & (1 << chan)))
	179	return 0;
7f528135 ML	180
	181	/* Deselect active channel */
	182	data->last_chan = 0;
7fcac980	183	return pca954x_reg_write(muxc->parent, client, data->last_chan);
7f528135 ML	184	}
	185
	186	/*
	187	* I2C init/probing/exit functions
	188	*/
db79f2a1 GR	189	static int pca954x_probe(struct i2c_client *client,
db79f2a1 GR	190	const struct i2c_device_id *id)
7f528135 ML	191	{
7f528135 ML	192	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
6d4028c6	193	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
72f02715 AS	194	struct device_node *of_node = client->dev.of_node;
72f02715 AS	195	bool idle_disconnect_dt;
4807e845	196	struct gpio_desc *gpio;
eee543e8	197	int num, force, class;
7fcac980	198	struct i2c_mux_core *muxc;
7f528135	199	struct pca954x *data;
bc12cfc8	200	int ret;
7f528135 ML	201
7f528135 ML	202	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
bc12cfc8	203	return -ENODEV;
7f528135	204
7fcac980 PR	205	muxc = i2c_mux_alloc(adap, &client->dev,
	206	PCA954X_MAX_NCHANS, sizeof(*data), 0,
	207	pca954x_select_chan, pca954x_deselect_mux);
	208	if (!muxc)
bc12cfc8	209	return -ENOMEM;
7fcac980	210	data = i2c_mux_priv(muxc);
7f528135	211
7fcac980 PR	212	i2c_set_clientdata(client, muxc);
7fcac980 PR	213	data->client = client;
7f528135	214
4807e845	215	/* Get the mux out of reset if a reset GPIO is specified. */
58b59e0f UKK	216	gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_LOW);
	217	if (IS_ERR(gpio))
	218	return PTR_ERR(gpio);
12097957	219
cd823db8 PG	220	/* Write the mux register at addr to verify
	221	* that the mux is in fact present. This also
	222	* initializes the mux to disconnected state.
7f528135	223	*/
cd823db8	224	if (i2c_smbus_write_byte(client, 0) < 0) {
7f528135	225	dev_warn(&client->dev, "probe failed\n");
bc12cfc8	226	return -ENODEV;
7f528135 ML	227	}
	228
	229	data->type = id->driver_data;
	230	data->last_chan = 0; /* force the first selection */
	231
72f02715 AS	232	idle_disconnect_dt = of_node &&
	233	of_property_read_bool(of_node, "i2c-mux-idle-disconnect");
	234
7f528135 ML	235	/* Now create an adapter for each channel */
7f528135 ML	236	for (num = 0; num < chips[data->type].nchans; num++) {
72f02715 AS	237	bool idle_disconnect_pd = false;
72f02715 AS	238
7f528135	239	force = 0; /* dynamic adap number */
eee543e8	240	class = 0; /* no class by default */
7f528135	241	if (pdata) {
eee543e8	242	if (num < pdata->num_modes) {
7f528135 ML	243	/* force static number */
7f528135 ML	244	force = pdata->modes[num].adap_id;
eee543e8 JD	245	class = pdata->modes[num].class;
eee543e8 JD	246	} else
7f528135 ML	247	/* discard unconfigured channels */
7f528135 ML	248	break;
72f02715	249	idle_disconnect_pd = pdata->modes[num].deselect_on_exit;
7fcac980 PR	250	data->deselect \|= (idle_disconnect_pd
7fcac980 PR	251	\|\| idle_disconnect_dt) << num;
7f528135 ML	252	}
7f528135 ML	253
7fcac980	254	ret = i2c_mux_add_adapter(muxc, force, num, class);
7f528135	255
7fcac980	256	if (ret) {
7f528135 ML	257	dev_err(&client->dev,
	258	"failed to register multiplexed adapter"
	259	" %d as bus %d\n", num, force);
	260	goto virt_reg_failed;
	261	}
	262	}
	263
	264	dev_info(&client->dev,
	265	"registered %d multiplexed busses for I2C %s %s\n",
	266	num, chips[data->type].muxtype == pca954x_ismux
	267	? "mux" : "switch", client->name);
	268
	269	return 0;
	270
	271	virt_reg_failed:
7fcac980	272	i2c_mux_del_adapters(muxc);
7f528135 ML	273	return ret;
	274	}
	275
db79f2a1	276	static int pca954x_remove(struct i2c_client *client)
7f528135	277	{
7fcac980	278	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
7f528135	279
7fcac980	280	i2c_mux_del_adapters(muxc);
7f528135 ML	281	return 0;
	282	}
	283
f5e596cd JZ	284	#ifdef CONFIG_PM_SLEEP
	285	static int pca954x_resume(struct device *dev)
	286	{
	287	struct i2c_client *client = to_i2c_client(dev);
7fcac980 PR	288	struct i2c_mux_core *muxc = i2c_get_clientdata(client);
7fcac980 PR	289	struct pca954x *data = i2c_mux_priv(muxc);
f5e596cd JZ	290
	291	data->last_chan = 0;
	292	return i2c_smbus_write_byte(client, 0);
	293	}
	294	#endif
	295
	296	static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
	297
7f528135 ML	298	static struct i2c_driver pca954x_driver = {
	299	.driver = {
	300	.name = "pca954x",
f5e596cd	301	.pm = &pca954x_pm,
7f528135 ML	302	},
7f528135 ML	303	.probe = pca954x_probe,
db79f2a1	304	.remove = pca954x_remove,
7f528135 ML	305	.id_table = pca954x_id,
	306	};
	307
de05497a	308	module_i2c_driver(pca954x_driver);
7f528135 ML	309
	310	MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
	311	MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
	312	MODULE_LICENSE("GPL v2");