[deliverable/linux.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 <khali@linux-fr.org>.
 *
 * 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/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/i2c/pca954x.h>
#include <linux/init.h>
#include <linux/module.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;
	struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS];

	u8 last_chan;		/* last register value */
};

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 = adap->algo->master_xfer(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_adapter *adap,
			       void *client, u32 chan)
{
	struct pca954x *data = i2c_get_clientdata(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(adap, client, regval);
		data->last_chan = regval;
	}

	return ret;
}

static int pca954x_deselect_mux(struct i2c_adapter *adap,
				void *client, u32 chan)
{
	struct pca954x *data = i2c_get_clientdata(client);

	/* Deselect active channel */
	data->last_chan = 0;
	return pca954x_reg_write(adap, 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);
	int num, force, class;
	struct pca954x *data;
	int ret;

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

	data = devm_kzalloc(&client->dev, sizeof(struct pca954x), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	i2c_set_clientdata(client, data);

	/* 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 */

	/* Now create an adapter for each channel */
	for (num = 0; num < chips[data->type].nchans; num++) {
		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;
		}

		data->virt_adaps[num] =
			i2c_add_mux_adapter(adap, &client->dev, client,
				force, num, class, pca954x_select_chan,
				(pdata && pdata->modes[num].deselect_on_exit)
					? pca954x_deselect_mux : NULL);

		if (data->virt_adaps[num] == NULL) {
			ret = -ENODEV;
			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:
	for (num--; num >= 0; num--)
		i2c_del_mux_adapter(data->virt_adaps[num]);
	return ret;
}

static int pca954x_remove(struct i2c_client *client)
{
	struct pca954x *data = i2c_get_clientdata(client);
	const struct chip_desc *chip = &chips[data->type];
	int i;

	for (i = 0; i < chip->nchans; ++i)
		if (data->virt_adaps[i]) {
			i2c_del_mux_adapter(data->virt_adaps[i]);
			data->virt_adaps[i] = NULL;
		}

	return 0;
}

static struct i2c_driver pca954x_driver = {
	.driver		= {
		.name	= "pca954x",
		.owner	= THIS_MODULE,
	},
	.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
	31	* pca9540.c from Jean Delvare <khali@linux-fr.org>.
	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 ML	38	#include <linux/device.h>
	39	#include <linux/i2c.h>
	40	#include <linux/i2c-mux.h>
7f528135	41	#include <linux/i2c/pca954x.h>
4b9b0073 LP	42	#include <linux/init.h>
	43	#include <linux/module.h>
	44	#include <linux/slab.h>
7f528135 ML	45
	46	#define PCA954X_MAX_NCHANS 8
	47
	48	enum pca_type {
	49	pca_9540,
	50	pca_9542,
	51	pca_9543,
	52	pca_9544,
	53	pca_9545,
	54	pca_9546,
	55	pca_9547,
	56	pca_9548,
	57	};
	58
	59	struct pca954x {
	60	enum pca_type type;
	61	struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS];
	62
	63	u8 last_chan; /* last register value */
	64	};
	65
	66	struct chip_desc {
	67	u8 nchans;
	68	u8 enable; /* used for muxes only */
	69	enum muxtype {
	70	pca954x_ismux = 0,
	71	pca954x_isswi
	72	} muxtype;
	73	};
	74
	75	/* Provide specs for the PCA954x types we know about */
	76	static const struct chip_desc chips[] = {
	77	[pca_9540] = {
	78	.nchans = 2,
	79	.enable = 0x4,
	80	.muxtype = pca954x_ismux,
	81	},
	82	[pca_9543] = {
	83	.nchans = 2,
	84	.muxtype = pca954x_isswi,
	85	},
	86	[pca_9544] = {
	87	.nchans = 4,
	88	.enable = 0x4,
	89	.muxtype = pca954x_ismux,
	90	},
	91	[pca_9545] = {
	92	.nchans = 4,
	93	.muxtype = pca954x_isswi,
	94	},
	95	[pca_9547] = {
	96	.nchans = 8,
	97	.enable = 0x8,
	98	.muxtype = pca954x_ismux,
	99	},
	100	[pca_9548] = {
	101	.nchans = 8,
	102	.muxtype = pca954x_isswi,
	103	},
	104	};
	105
	106	static const struct i2c_device_id pca954x_id[] = {
	107	{ "pca9540", pca_9540 },
	108	{ "pca9542", pca_9540 },
109	{ "pca9543", pca_9543 },
110	{ "pca9544", pca_9544 },
111	{ "pca9545", pca_9545 },
112	{ "pca9546", pca_9545 },
113	{ "pca9547", pca_9547 },
114	{ "pca9548", pca_9548 },
115	{ }
116	};
117	MODULE_DEVICE_TABLE(i2c, pca954x_id);
118
119	/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
120	for this as they will try to lock adapter a second time */
121	static int pca954x_reg_write(struct i2c_adapter *adap,
122	struct i2c_client *client, u8 val)
123	{
124	int ret = -ENODEV;
125
126	if (adap->algo->master_xfer) {
127	struct i2c_msg msg;
128	char buf[1];
129
130	msg.addr = client->addr;
131	msg.flags = 0;
132	msg.len = 1;
133	buf[0] = val;
134	msg.buf = buf;
135	ret = adap->algo->master_xfer(adap, &msg, 1);
136	} else {
137	union i2c_smbus_data data;
138	ret = adap->algo->smbus_xfer(adap, client->addr,
139	client->flags,
140	I2C_SMBUS_WRITE,
141	val, I2C_SMBUS_BYTE, &data);
142	}
143
144	return ret;
145	}
146
147	static int pca954x_select_chan(struct i2c_adapter *adap,
148	void *client, u32 chan)
149	{
150	struct pca954x *data = i2c_get_clientdata(client);
151	const struct chip_desc *chip = &chips[data->type];
152	u8 regval;
153	int ret = 0;
154
155	/* we make switches look like muxes, not sure how to be smarter */
156	if (chip->muxtype == pca954x_ismux)
157	regval = chan \| chip->enable;
158	else
159	regval = 1 << chan;
160
161	/* Only select the channel if its different from the last channel */
162	if (data->last_chan != regval) {
163	ret = pca954x_reg_write(adap, client, regval);
164	data->last_chan = regval;
165	}
166
167	return ret;
168	}
169
170	static int pca954x_deselect_mux(struct i2c_adapter *adap,
171	void *client, u32 chan)
172	{
173	struct pca954x *data = i2c_get_clientdata(client);
174
175	/* Deselect active channel */
176	data->last_chan = 0;
177	return pca954x_reg_write(adap, client, data->last_chan);
178	}
179
180	/*
181	* I2C init/probing/exit functions
182	*/
db79f2a1 GR	183	static int pca954x_probe(struct i2c_client *client,
db79f2a1 GR	184	const struct i2c_device_id *id)
7f528135 ML	185	{
7f528135 ML	186	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
6d4028c6	187	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
eee543e8	188	int num, force, class;
7f528135	189	struct pca954x *data;
bc12cfc8	190	int ret;
7f528135 ML	191
7f528135 ML	192	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
bc12cfc8	193	return -ENODEV;
7f528135	194
bc12cfc8 LP	195	data = devm_kzalloc(&client->dev, sizeof(struct pca954x), GFP_KERNEL);
	196	if (!data)
	197	return -ENOMEM;
7f528135 ML	198
	199	i2c_set_clientdata(client, data);
	200
cd823db8 PG	201	/* Write the mux register at addr to verify
	202	* that the mux is in fact present. This also
	203	* initializes the mux to disconnected state.
7f528135	204	*/
cd823db8	205	if (i2c_smbus_write_byte(client, 0) < 0) {
7f528135	206	dev_warn(&client->dev, "probe failed\n");
bc12cfc8	207	return -ENODEV;
7f528135 ML	208	}
	209
	210	data->type = id->driver_data;
	211	data->last_chan = 0; /* force the first selection */
	212
	213	/* Now create an adapter for each channel */
	214	for (num = 0; num < chips[data->type].nchans; num++) {
	215	force = 0; /* dynamic adap number */
eee543e8	216	class = 0; /* no class by default */
7f528135	217	if (pdata) {
eee543e8	218	if (num < pdata->num_modes) {
7f528135 ML	219	/* force static number */
7f528135 ML	220	force = pdata->modes[num].adap_id;
eee543e8 JD	221	class = pdata->modes[num].class;
eee543e8 JD	222	} else
7f528135 ML	223	/* discard unconfigured channels */
	224	break;
	225	}
	226
	227	data->virt_adaps[num] =
5a3ecd5f	228	i2c_add_mux_adapter(adap, &client->dev, client,
eee543e8	229	force, num, class, pca954x_select_chan,
7f528135 ML	230	(pdata && pdata->modes[num].deselect_on_exit)
	231	? pca954x_deselect_mux : NULL);
	232
	233	if (data->virt_adaps[num] == NULL) {
	234	ret = -ENODEV;
	235	dev_err(&client->dev,
	236	"failed to register multiplexed adapter"
	237	" %d as bus %d\n", num, force);
	238	goto virt_reg_failed;
	239	}
	240	}
	241
	242	dev_info(&client->dev,
	243	"registered %d multiplexed busses for I2C %s %s\n",
	244	num, chips[data->type].muxtype == pca954x_ismux
	245	? "mux" : "switch", client->name);
	246
	247	return 0;
	248
	249	virt_reg_failed:
	250	for (num--; num >= 0; num--)
	251	i2c_del_mux_adapter(data->virt_adaps[num]);
7f528135 ML	252	return ret;
	253	}
	254
db79f2a1	255	static int pca954x_remove(struct i2c_client *client)
7f528135 ML	256	{
	257	struct pca954x *data = i2c_get_clientdata(client);
	258	const struct chip_desc *chip = &chips[data->type];
a205e63d	259	int i;
7f528135 ML	260
	261	for (i = 0; i < chip->nchans; ++i)
	262	if (data->virt_adaps[i]) {
a205e63d	263	i2c_del_mux_adapter(data->virt_adaps[i]);
7f528135 ML	264	data->virt_adaps[i] = NULL;
	265	}
	266
7f528135 ML	267	return 0;
	268	}
	269
	270	static struct i2c_driver pca954x_driver = {
	271	.driver = {
	272	.name = "pca954x",
	273	.owner = THIS_MODULE,
	274	},
	275	.probe = pca954x_probe,
db79f2a1	276	.remove = pca954x_remove,
7f528135 ML	277	.id_table = pca954x_id,
	278	};
	279
de05497a	280	module_i2c_driver(pca954x_driver);
7f528135 ML	281
	282	MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
	283	MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
	284	MODULE_LICENSE("GPL v2");