[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 <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/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/i2c-mux.h>

#include <linux/i2c/pca954x.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 = client->dev.platform_data;
	int num, force, class;
	struct pca954x *data;
	int ret = -ENODEV;

	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
		goto err;

	data = kzalloc(sizeof(struct pca954x), GFP_KERNEL);
	if (!data) {
		ret = -ENOMEM;
		goto err;
	}

	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");
		goto exit_free;
	}

	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]);
exit_free:
	kfree(data);
err:
	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, err;

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

	kfree(data);
	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
	38	#include <linux/module.h>
	39	#include <linux/init.h>
	40	#include <linux/slab.h>
	41	#include <linux/device.h>
	42	#include <linux/i2c.h>
	43	#include <linux/i2c-mux.h>
	44
	45	#include <linux/i2c/pca954x.h>
	46
	47	#define PCA954X_MAX_NCHANS 8
	48
	49	enum pca_type {
	50	pca_9540,
	51	pca_9542,
	52	pca_9543,
	53	pca_9544,
	54	pca_9545,
	55	pca_9546,
	56	pca_9547,
	57	pca_9548,
	58	};
	59
	60	struct pca954x {
	61	enum pca_type type;
	62	struct i2c_adapter *virt_adaps[PCA954X_MAX_NCHANS];
	63
	64	u8 last_chan; /* last register value */
65	};
66
67	struct chip_desc {
68	u8 nchans;
69	u8 enable; /* used for muxes only */
70	enum muxtype {
71	pca954x_ismux = 0,
72	pca954x_isswi
73	} muxtype;
74	};
75
76	/* Provide specs for the PCA954x types we know about */
77	static const struct chip_desc chips[] = {
78	[pca_9540] = {
79	.nchans = 2,
80	.enable = 0x4,
81	.muxtype = pca954x_ismux,
82	},
83	[pca_9543] = {
84	.nchans = 2,
85	.muxtype = pca954x_isswi,
86	},
87	[pca_9544] = {
88	.nchans = 4,
89	.enable = 0x4,
90	.muxtype = pca954x_ismux,
91	},
92	[pca_9545] = {
93	.nchans = 4,
94	.muxtype = pca954x_isswi,
95	},
96	[pca_9547] = {
97	.nchans = 8,
98	.enable = 0x8,
99	.muxtype = pca954x_ismux,
100	},
101	[pca_9548] = {
102	.nchans = 8,
103	.muxtype = pca954x_isswi,
104	},
105	};
106
107	static const struct i2c_device_id pca954x_id[] = {
108	{ "pca9540", pca_9540 },
109	{ "pca9542", pca_9540 },
110	{ "pca9543", pca_9543 },
111	{ "pca9544", pca_9544 },
112	{ "pca9545", pca_9545 },
113	{ "pca9546", pca_9545 },
114	{ "pca9547", pca_9547 },
115	{ "pca9548", pca_9548 },
116	{ }
117	};
118	MODULE_DEVICE_TABLE(i2c, pca954x_id);
119
120	/* Write to mux register. Don't use i2c_transfer()/i2c_smbus_xfer()
121	for this as they will try to lock adapter a second time */
122	static int pca954x_reg_write(struct i2c_adapter *adap,
123	struct i2c_client *client, u8 val)
124	{
125	int ret = -ENODEV;
126
127	if (adap->algo->master_xfer) {
128	struct i2c_msg msg;
129	char buf[1];
130
131	msg.addr = client->addr;
132	msg.flags = 0;
133	msg.len = 1;
134	buf[0] = val;
135	msg.buf = buf;
136	ret = adap->algo->master_xfer(adap, &msg, 1);
137	} else {
138	union i2c_smbus_data data;
139	ret = adap->algo->smbus_xfer(adap, client->addr,
140	client->flags,
141	I2C_SMBUS_WRITE,
142	val, I2C_SMBUS_BYTE, &data);
143	}
144
145	return ret;
146	}
147
148	static int pca954x_select_chan(struct i2c_adapter *adap,
149	void *client, u32 chan)
150	{
151	struct pca954x *data = i2c_get_clientdata(client);
152	const struct chip_desc *chip = &chips[data->type];
153	u8 regval;
154	int ret = 0;
155
156	/* we make switches look like muxes, not sure how to be smarter */
157	if (chip->muxtype == pca954x_ismux)
158	regval = chan \| chip->enable;
159	else
160	regval = 1 << chan;
161
162	/* Only select the channel if its different from the last channel */
163	if (data->last_chan != regval) {
164	ret = pca954x_reg_write(adap, client, regval);
165	data->last_chan = regval;
166	}
167
168	return ret;
169	}
170
171	static int pca954x_deselect_mux(struct i2c_adapter *adap,
172	void *client, u32 chan)
173	{
174	struct pca954x *data = i2c_get_clientdata(client);
175
176	/* Deselect active channel */
177	data->last_chan = 0;
178	return pca954x_reg_write(adap, client, data->last_chan);
179	}
180
181	/*
182	* I2C init/probing/exit functions
183	*/
db79f2a1 GR	184	static int pca954x_probe(struct i2c_client *client,
db79f2a1 GR	185	const struct i2c_device_id *id)
7f528135 ML	186	{
	187	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
	188	struct pca954x_platform_data *pdata = client->dev.platform_data;
eee543e8	189	int num, force, class;
7f528135 ML	190	struct pca954x *data;
	191	int ret = -ENODEV;
	192
	193	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
	194	goto err;
	195
	196	data = kzalloc(sizeof(struct pca954x), GFP_KERNEL);
	197	if (!data) {
	198	ret = -ENOMEM;
	199	goto err;
	200	}
	201
	202	i2c_set_clientdata(client, data);
	203
cd823db8 PG	204	/* Write the mux register at addr to verify
	205	* that the mux is in fact present. This also
	206	* initializes the mux to disconnected state.
7f528135	207	*/
cd823db8	208	if (i2c_smbus_write_byte(client, 0) < 0) {
7f528135 ML	209	dev_warn(&client->dev, "probe failed\n");
	210	goto exit_free;
	211	}
	212
	213	data->type = id->driver_data;
	214	data->last_chan = 0; /* force the first selection */
	215
	216	/* Now create an adapter for each channel */
	217	for (num = 0; num < chips[data->type].nchans; num++) {
	218	force = 0; /* dynamic adap number */
eee543e8	219	class = 0; /* no class by default */
7f528135	220	if (pdata) {
eee543e8	221	if (num < pdata->num_modes) {
7f528135 ML	222	/* force static number */
7f528135 ML	223	force = pdata->modes[num].adap_id;
eee543e8 JD	224	class = pdata->modes[num].class;
eee543e8 JD	225	} else
7f528135 ML	226	/* discard unconfigured channels */
	227	break;
	228	}
	229
	230	data->virt_adaps[num] =
5a3ecd5f	231	i2c_add_mux_adapter(adap, &client->dev, client,
eee543e8	232	force, num, class, pca954x_select_chan,
7f528135 ML	233	(pdata && pdata->modes[num].deselect_on_exit)
	234	? pca954x_deselect_mux : NULL);
	235
	236	if (data->virt_adaps[num] == NULL) {
	237	ret = -ENODEV;
	238	dev_err(&client->dev,
	239	"failed to register multiplexed adapter"
	240	" %d as bus %d\n", num, force);
	241	goto virt_reg_failed;
	242	}
	243	}
	244
	245	dev_info(&client->dev,
	246	"registered %d multiplexed busses for I2C %s %s\n",
	247	num, chips[data->type].muxtype == pca954x_ismux
	248	? "mux" : "switch", client->name);
	249
	250	return 0;
	251
	252	virt_reg_failed:
	253	for (num--; num >= 0; num--)
	254	i2c_del_mux_adapter(data->virt_adaps[num]);
	255	exit_free:
	256	kfree(data);
	257	err:
	258	return ret;
	259	}
	260
db79f2a1	261	static int pca954x_remove(struct i2c_client *client)
7f528135 ML	262	{
	263	struct pca954x *data = i2c_get_clientdata(client);
	264	const struct chip_desc *chip = &chips[data->type];
	265	int i, err;
	266
	267	for (i = 0; i < chip->nchans; ++i)
	268	if (data->virt_adaps[i]) {
	269	err = i2c_del_mux_adapter(data->virt_adaps[i]);
	270	if (err)
	271	return err;
	272	data->virt_adaps[i] = NULL;
	273	}
	274
	275	kfree(data);
	276	return 0;
	277	}
	278
	279	static struct i2c_driver pca954x_driver = {
	280	.driver = {
	281	.name = "pca954x",
	282	.owner = THIS_MODULE,
	283	},
	284	.probe = pca954x_probe,
db79f2a1	285	.remove = pca954x_remove,
7f528135 ML	286	.id_table = pca954x_id,
	287	};
	288
de05497a	289	module_i2c_driver(pca954x_driver);
7f528135 ML	290
	291	MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
	292	MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
	293	MODULE_LICENSE("GPL v2");