[linux-2.6-block.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/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;
	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);
	struct gpio_desc *gpio;
	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);

	/* Get the mux out of reset if a reset GPIO is specified. */
	gpio = devm_gpiod_get(&client->dev, "reset");
	if (!IS_ERR(gpio))
		gpiod_direction_output(gpio, 0);

	/* 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;
}

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

	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,
		.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
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>
f5e596cd	44	#include <linux/pm.h>
4b9b0073	45	#include <linux/slab.h>
7f528135 ML	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	{
7f528135 ML	187	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
6d4028c6	188	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
4807e845	189	struct gpio_desc *gpio;
eee543e8	190	int num, force, class;
7f528135	191	struct pca954x *data;
bc12cfc8	192	int ret;
7f528135 ML	193
7f528135 ML	194	if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_BYTE))
bc12cfc8	195	return -ENODEV;
7f528135	196
bc12cfc8 LP	197	data = devm_kzalloc(&client->dev, sizeof(struct pca954x), GFP_KERNEL);
	198	if (!data)
	199	return -ENOMEM;
7f528135 ML	200
	201	i2c_set_clientdata(client, data);
	202
4807e845 LP	203	/* Get the mux out of reset if a reset GPIO is specified. */
	204	gpio = devm_gpiod_get(&client->dev, "reset");
	205	if (!IS_ERR(gpio))
	206	gpiod_direction_output(gpio, 0);
12097957	207
cd823db8 PG	208	/* Write the mux register at addr to verify
	209	* that the mux is in fact present. This also
	210	* initializes the mux to disconnected state.
7f528135	211	*/
cd823db8	212	if (i2c_smbus_write_byte(client, 0) < 0) {
7f528135	213	dev_warn(&client->dev, "probe failed\n");
bc12cfc8	214	return -ENODEV;
7f528135 ML	215	}
	216
	217	data->type = id->driver_data;
	218	data->last_chan = 0; /* force the first selection */
	219
	220	/* Now create an adapter for each channel */
	221	for (num = 0; num < chips[data->type].nchans; num++) {
	222	force = 0; /* dynamic adap number */
eee543e8	223	class = 0; /* no class by default */
7f528135	224	if (pdata) {
eee543e8	225	if (num < pdata->num_modes) {
7f528135 ML	226	/* force static number */
7f528135 ML	227	force = pdata->modes[num].adap_id;
eee543e8 JD	228	class = pdata->modes[num].class;
eee543e8 JD	229	} else
7f528135 ML	230	/* discard unconfigured channels */
	231	break;
	232	}
	233
	234	data->virt_adaps[num] =
5a3ecd5f	235	i2c_add_mux_adapter(adap, &client->dev, client,
eee543e8	236	force, num, class, pca954x_select_chan,
7f528135 ML	237	(pdata && pdata->modes[num].deselect_on_exit)
	238	? pca954x_deselect_mux : NULL);
	239
	240	if (data->virt_adaps[num] == NULL) {
	241	ret = -ENODEV;
	242	dev_err(&client->dev,
	243	"failed to register multiplexed adapter"
	244	" %d as bus %d\n", num, force);
	245	goto virt_reg_failed;
	246	}
	247	}
	248
	249	dev_info(&client->dev,
	250	"registered %d multiplexed busses for I2C %s %s\n",
	251	num, chips[data->type].muxtype == pca954x_ismux
	252	? "mux" : "switch", client->name);
	253
	254	return 0;
	255
	256	virt_reg_failed:
	257	for (num--; num >= 0; num--)
	258	i2c_del_mux_adapter(data->virt_adaps[num]);
7f528135 ML	259	return ret;
	260	}
	261
db79f2a1	262	static int pca954x_remove(struct i2c_client *client)
7f528135 ML	263	{
	264	struct pca954x *data = i2c_get_clientdata(client);
	265	const struct chip_desc *chip = &chips[data->type];
a205e63d	266	int i;
7f528135 ML	267
	268	for (i = 0; i < chip->nchans; ++i)
	269	if (data->virt_adaps[i]) {
a205e63d	270	i2c_del_mux_adapter(data->virt_adaps[i]);
7f528135 ML	271	data->virt_adaps[i] = NULL;
	272	}
	273
7f528135 ML	274	return 0;
	275	}
	276
f5e596cd JZ	277	#ifdef CONFIG_PM_SLEEP
	278	static int pca954x_resume(struct device *dev)
	279	{
	280	struct i2c_client *client = to_i2c_client(dev);
	281	struct pca954x *data = i2c_get_clientdata(client);
	282
	283	data->last_chan = 0;
	284	return i2c_smbus_write_byte(client, 0);
	285	}
	286	#endif
	287
	288	static SIMPLE_DEV_PM_OPS(pca954x_pm, NULL, pca954x_resume);
	289
7f528135 ML	290	static struct i2c_driver pca954x_driver = {
	291	.driver = {
	292	.name = "pca954x",
f5e596cd	293	.pm = &pca954x_pm,
7f528135 ML	294	.owner = THIS_MODULE,
	295	},
	296	.probe = pca954x_probe,
db79f2a1	297	.remove = pca954x_remove,
7f528135 ML	298	.id_table = pca954x_id,
	299	};
	300
de05497a	301	module_i2c_driver(pca954x_driver);
7f528135 ML	302
	303	MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
	304	MODULE_DESCRIPTION("PCA954x I2C mux/switch driver");
	305	MODULE_LICENSE("GPL v2");