[deliverable/linux.git] / drivers / i2c / muxes / i2c-mux-gpio.c

/*
 * I2C multiplexer using GPIO API
 *
 * Peter Korsgaard <peter.korsgaard@barco.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/i2c-mux-gpio.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/gpio.h>
#include <linux/of_gpio.h>

struct gpiomux {
	struct i2c_adapter *parent;
	struct i2c_adapter **adap; /* child busses */
	struct i2c_mux_gpio_platform_data data;
	unsigned gpio_base;
};

static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val)
{
	int i;

	for (i = 0; i < mux->data.n_gpios; i++)
		gpio_set_value(mux->gpio_base + mux->data.gpios[i],
			       val & (1 << i));
}

static int i2c_mux_gpio_select(struct i2c_adapter *adap, void *data, u32 chan)
{
	struct gpiomux *mux = data;

	i2c_mux_gpio_set(mux, mux->data.values[chan]);

	return 0;
}

static int i2c_mux_gpio_deselect(struct i2c_adapter *adap, void *data, u32 chan)
{
	struct gpiomux *mux = data;

	i2c_mux_gpio_set(mux, mux->data.idle);

	return 0;
}

static int match_gpio_chip_by_label(struct gpio_chip *chip,
					      void *data)
{
	return !strcmp(chip->label, data);
}

#ifdef CONFIG_OF
static int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
					struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct device_node *adapter_np, *child;
	struct i2c_adapter *adapter;
	unsigned *values, *gpios;
	int i = 0, ret;

	if (!np)
		return -ENODEV;

	adapter_np = of_parse_phandle(np, "i2c-parent", 0);
	if (!adapter_np) {
		dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
		return -ENODEV;
	}
	adapter = of_find_i2c_adapter_by_node(adapter_np);
	if (!adapter) {
		dev_err(&pdev->dev, "Cannot find parent bus\n");
		return -EPROBE_DEFER;
	}
	mux->data.parent = i2c_adapter_id(adapter);
	put_device(&adapter->dev);

	mux->data.n_values = of_get_child_count(np);

	values = devm_kzalloc(&pdev->dev,
			      sizeof(*mux->data.values) * mux->data.n_values,
			      GFP_KERNEL);
	if (!values) {
		dev_err(&pdev->dev, "Cannot allocate values array");
		return -ENOMEM;
	}

	for_each_child_of_node(np, child) {
		of_property_read_u32(child, "reg", values + i);
		i++;
	}
	mux->data.values = values;

	if (of_property_read_u32(np, "idle-state", &mux->data.idle))
		mux->data.idle = I2C_MUX_GPIO_NO_IDLE;

	mux->data.n_gpios = of_gpio_named_count(np, "mux-gpios");
	if (mux->data.n_gpios < 0) {
		dev_err(&pdev->dev, "Missing mux-gpios property in the DT.\n");
		return -EINVAL;
	}

	gpios = devm_kzalloc(&pdev->dev,
			     sizeof(*mux->data.gpios) * mux->data.n_gpios, GFP_KERNEL);
	if (!gpios) {
		dev_err(&pdev->dev, "Cannot allocate gpios array");
		return -ENOMEM;
	}

	for (i = 0; i < mux->data.n_gpios; i++) {
		ret = of_get_named_gpio(np, "mux-gpios", i);
		if (ret < 0)
			return ret;
		gpios[i] = ret;
	}

	mux->data.gpios = gpios;

	return 0;
}
#else
static int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
					struct platform_device *pdev)
{
	return 0;
}
#endif

static int i2c_mux_gpio_probe(struct platform_device *pdev)
{
	struct gpiomux *mux;
	struct i2c_adapter *parent;
	int (*deselect) (struct i2c_adapter *, void *, u32);
	unsigned initial_state, gpio_base;
	int i, ret;

	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
	if (!mux) {
		dev_err(&pdev->dev, "Cannot allocate gpiomux structure");
		return -ENOMEM;
	}

	platform_set_drvdata(pdev, mux);

	if (!dev_get_platdata(&pdev->dev)) {
		ret = i2c_mux_gpio_probe_dt(mux, pdev);
		if (ret < 0)
			return ret;
	} else {
		memcpy(&mux->data, dev_get_platdata(&pdev->dev),
			sizeof(mux->data));
	}

	/*
	 * If a GPIO chip name is provided, the GPIO pin numbers provided are
	 * relative to its base GPIO number. Otherwise they are absolute.
	 */
	if (mux->data.gpio_chip) {
		struct gpio_chip *gpio;

		gpio = gpiochip_find(mux->data.gpio_chip,
				     match_gpio_chip_by_label);
		if (!gpio)
			return -EPROBE_DEFER;

		gpio_base = gpio->base;
	} else {
		gpio_base = 0;
	}

	parent = i2c_get_adapter(mux->data.parent);
	if (!parent) {
		dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
			mux->data.parent);
		return -EPROBE_DEFER;
	}

	mux->parent = parent;
	mux->gpio_base = gpio_base;

	mux->adap = devm_kzalloc(&pdev->dev,
				 sizeof(*mux->adap) * mux->data.n_values,
				 GFP_KERNEL);
	if (!mux->adap) {
		dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure");
		ret = -ENOMEM;
		goto alloc_failed;
	}

	if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) {
		initial_state = mux->data.idle;
		deselect = i2c_mux_gpio_deselect;
	} else {
		initial_state = mux->data.values[0];
		deselect = NULL;
	}

	for (i = 0; i < mux->data.n_gpios; i++) {
		ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio");
		if (ret) {
			dev_err(&pdev->dev, "Failed to request GPIO %d\n",
				mux->data.gpios[i]);
			goto err_request_gpio;
		}

		ret = gpio_direction_output(gpio_base + mux->data.gpios[i],
					    initial_state & (1 << i));
		if (ret) {
			dev_err(&pdev->dev,
				"Failed to set direction of GPIO %d to output\n",
				mux->data.gpios[i]);
			i++;	/* gpio_request above succeeded, so must free */
			goto err_request_gpio;
		}
	}

	for (i = 0; i < mux->data.n_values; i++) {
		u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
		unsigned int class = mux->data.classes ? mux->data.classes[i] : 0;

		mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr,
						   i, class,
						   i2c_mux_gpio_select, deselect);
		if (!mux->adap[i]) {
			ret = -ENODEV;
			dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
			goto add_adapter_failed;
		}
	}

	dev_info(&pdev->dev, "%d port mux on %s adapter\n",
		 mux->data.n_values, parent->name);

	return 0;

add_adapter_failed:
	for (; i > 0; i--)
		i2c_del_mux_adapter(mux->adap[i - 1]);
	i = mux->data.n_gpios;
err_request_gpio:
	for (; i > 0; i--)
		gpio_free(gpio_base + mux->data.gpios[i - 1]);
alloc_failed:
	i2c_put_adapter(parent);

	return ret;
}

static int i2c_mux_gpio_remove(struct platform_device *pdev)
{
	struct gpiomux *mux = platform_get_drvdata(pdev);
	int i;

	for (i = 0; i < mux->data.n_values; i++)
		i2c_del_mux_adapter(mux->adap[i]);

	for (i = 0; i < mux->data.n_gpios; i++)
		gpio_free(mux->gpio_base + mux->data.gpios[i]);

	i2c_put_adapter(mux->parent);

	return 0;
}

static const struct of_device_id i2c_mux_gpio_of_match[] = {
	{ .compatible = "i2c-mux-gpio", },
	{},
};
MODULE_DEVICE_TABLE(of, i2c_mux_gpio_of_match);

static struct platform_driver i2c_mux_gpio_driver = {
	.probe	= i2c_mux_gpio_probe,
	.remove	= i2c_mux_gpio_remove,
	.driver	= {
		.owner	= THIS_MODULE,
		.name	= "i2c-mux-gpio",
		.of_match_table = of_match_ptr(i2c_mux_gpio_of_match),
	},
};

module_platform_driver(i2c_mux_gpio_driver);

MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver");
MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:i2c-mux-gpio");
Commit	Line	Data
92ed1a76 PK	1	/*
	2	* I2C multiplexer using GPIO API
	3	*
	4	* Peter Korsgaard <peter.korsgaard@barco.com>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*/
	10
	11	#include <linux/i2c.h>
	12	#include <linux/i2c-mux.h>
e7065e20	13	#include <linux/i2c-mux-gpio.h>
92ed1a76 PK	14	#include <linux/platform_device.h>
	15	#include <linux/init.h>
	16	#include <linux/module.h>
	17	#include <linux/slab.h>
	18	#include <linux/gpio.h>
9b7a0c40	19	#include <linux/of_gpio.h>
92ed1a76 PK	20
	21	struct gpiomux {
	22	struct i2c_adapter *parent;
	23	struct i2c_adapter *adap; / child busses */
e7065e20	24	struct i2c_mux_gpio_platform_data data;
e7ee5140	25	unsigned gpio_base;
92ed1a76 PK	26	};
92ed1a76 PK	27
e7065e20	28	static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val)
92ed1a76 PK	29	{
	30	int i;
	31
	32	for (i = 0; i < mux->data.n_gpios; i++)
e7ee5140 JD	33	gpio_set_value(mux->gpio_base + mux->data.gpios[i],
e7ee5140 JD	34	val & (1 << i));
92ed1a76 PK	35	}
92ed1a76 PK	36
e7065e20	37	static int i2c_mux_gpio_select(struct i2c_adapter adap, void data, u32 chan)
92ed1a76 PK	38	{
	39	struct gpiomux *mux = data;
	40
e7065e20	41	i2c_mux_gpio_set(mux, mux->data.values[chan]);
92ed1a76 PK	42
	43	return 0;
	44	}
	45
e7065e20	46	static int i2c_mux_gpio_deselect(struct i2c_adapter adap, void data, u32 chan)
92ed1a76 PK	47	{
	48	struct gpiomux *mux = data;
	49
e7065e20	50	i2c_mux_gpio_set(mux, mux->data.idle);
92ed1a76 PK	51
	52	return 0;
	53	}
	54
0b255e92	55	static int match_gpio_chip_by_label(struct gpio_chip *chip,
e7ee5140 JD	56	void *data)
	57	{
	58	return !strcmp(chip->label, data);
	59	}
	60
9b7a0c40	61	#ifdef CONFIG_OF
0b255e92	62	static int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
9b7a0c40 MR	63	struct platform_device *pdev)
	64	{
	65	struct device_node *np = pdev->dev.of_node;
	66	struct device_node adapter_np, child;
	67	struct i2c_adapter *adapter;
	68	unsigned values, gpios;
492ed77b	69	int i = 0, ret;
9b7a0c40 MR	70
	71	if (!np)
	72	return -ENODEV;
	73
	74	adapter_np = of_parse_phandle(np, "i2c-parent", 0);
	75	if (!adapter_np) {
	76	dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
	77	return -ENODEV;
	78	}
	79	adapter = of_find_i2c_adapter_by_node(adapter_np);
	80	if (!adapter) {
	81	dev_err(&pdev->dev, "Cannot find parent bus\n");
9937b8d8	82	return -EPROBE_DEFER;
9b7a0c40 MR	83	}
	84	mux->data.parent = i2c_adapter_id(adapter);
	85	put_device(&adapter->dev);
	86
	87	mux->data.n_values = of_get_child_count(np);
	88
	89	values = devm_kzalloc(&pdev->dev,
	90	sizeof(mux->data.values) mux->data.n_values,
	91	GFP_KERNEL);
	92	if (!values) {
	93	dev_err(&pdev->dev, "Cannot allocate values array");
	94	return -ENOMEM;
	95	}
	96
	97	for_each_child_of_node(np, child) {
	98	of_property_read_u32(child, "reg", values + i);
	99	i++;
	100	}
	101	mux->data.values = values;
	102
	103	if (of_property_read_u32(np, "idle-state", &mux->data.idle))
	104	mux->data.idle = I2C_MUX_GPIO_NO_IDLE;
	105
	106	mux->data.n_gpios = of_gpio_named_count(np, "mux-gpios");
	107	if (mux->data.n_gpios < 0) {
	108	dev_err(&pdev->dev, "Missing mux-gpios property in the DT.\n");
	109	return -EINVAL;
	110	}
	111
	112	gpios = devm_kzalloc(&pdev->dev,
	113	sizeof(mux->data.gpios) mux->data.n_gpios, GFP_KERNEL);
	114	if (!gpios) {
	115	dev_err(&pdev->dev, "Cannot allocate gpios array");
	116	return -ENOMEM;
	117	}
	118
492ed77b IN	119	for (i = 0; i < mux->data.n_gpios; i++) {
	120	ret = of_get_named_gpio(np, "mux-gpios", i);
	121	if (ret < 0)
	122	return ret;
	123	gpios[i] = ret;
	124	}
9b7a0c40 MR	125
	126	mux->data.gpios = gpios;
	127
	128	return 0;
	129	}
	130	#else
0b255e92	131	static int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
9b7a0c40 MR	132	struct platform_device *pdev)
	133	{
	134	return 0;
	135	}
	136	#endif
	137
0b255e92	138	static int i2c_mux_gpio_probe(struct platform_device *pdev)
92ed1a76 PK	139	{
92ed1a76 PK	140	struct gpiomux *mux;
92ed1a76 PK	141	struct i2c_adapter *parent;
92ed1a76 PK	142	int (deselect) (struct i2c_adapter , void *, u32);
e7ee5140	143	unsigned initial_state, gpio_base;
92ed1a76 PK	144	int i, ret;
92ed1a76 PK	145
9b7a0c40 MR	146	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
	147	if (!mux) {
	148	dev_err(&pdev->dev, "Cannot allocate gpiomux structure");
	149	return -ENOMEM;
92ed1a76 PK	150	}
92ed1a76 PK	151
9b7a0c40 MR	152	platform_set_drvdata(pdev, mux);
9b7a0c40 MR	153
6d4028c6	154	if (!dev_get_platdata(&pdev->dev)) {
9b7a0c40 MR	155	ret = i2c_mux_gpio_probe_dt(mux, pdev);
	156	if (ret < 0)
	157	return ret;
6d4028c6 JH	158	} else {
	159	memcpy(&mux->data, dev_get_platdata(&pdev->dev),
	160	sizeof(mux->data));
	161	}
9b7a0c40	162
e7ee5140 JD	163	/*
	164	* If a GPIO chip name is provided, the GPIO pin numbers provided are
	165	* relative to its base GPIO number. Otherwise they are absolute.
	166	*/
9b7a0c40	167	if (mux->data.gpio_chip) {
e7ee5140 JD	168	struct gpio_chip *gpio;
e7ee5140 JD	169
9b7a0c40	170	gpio = gpiochip_find(mux->data.gpio_chip,
e7ee5140 JD	171	match_gpio_chip_by_label);
	172	if (!gpio)
	173	return -EPROBE_DEFER;
	174
	175	gpio_base = gpio->base;
	176	} else {
	177	gpio_base = 0;
	178	}
	179
9b7a0c40	180	parent = i2c_get_adapter(mux->data.parent);
92ed1a76 PK	181	if (!parent) {
92ed1a76 PK	182	dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
9b7a0c40	183	mux->data.parent);
9937b8d8	184	return -EPROBE_DEFER;
92ed1a76 PK	185	}
92ed1a76 PK	186
92ed1a76	187	mux->parent = parent;
e7ee5140	188	mux->gpio_base = gpio_base;
9b7a0c40	189
2614a859	190	mux->adap = devm_kzalloc(&pdev->dev,
9b7a0c40	191	sizeof(mux->adap) mux->data.n_values,
2614a859	192	GFP_KERNEL);
92ed1a76	193	if (!mux->adap) {
9b7a0c40	194	dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure");
92ed1a76	195	ret = -ENOMEM;
2614a859	196	goto alloc_failed;
92ed1a76 PK	197	}
92ed1a76 PK	198
9b7a0c40 MR	199	if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) {
9b7a0c40 MR	200	initial_state = mux->data.idle;
e7065e20	201	deselect = i2c_mux_gpio_deselect;
92ed1a76	202	} else {
9b7a0c40	203	initial_state = mux->data.values[0];
92ed1a76 PK	204	deselect = NULL;
	205	}
	206
9b7a0c40 MR	207	for (i = 0; i < mux->data.n_gpios; i++) {
9b7a0c40 MR	208	ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio");
7fafae66 JD	209	if (ret) {
	210	dev_err(&pdev->dev, "Failed to request GPIO %d\n",
	211	mux->data.gpios[i]);
92ed1a76	212	goto err_request_gpio;
7fafae66 JD	213	}
	214
	215	ret = gpio_direction_output(gpio_base + mux->data.gpios[i],
	216	initial_state & (1 << i));
	217	if (ret) {
	218	dev_err(&pdev->dev,
	219	"Failed to set direction of GPIO %d to output\n",
	220	mux->data.gpios[i]);
	221	i++; /* gpio_request above succeeded, so must free */
	222	goto err_request_gpio;
	223	}
92ed1a76 PK	224	}
92ed1a76 PK	225
9b7a0c40 MR	226	for (i = 0; i < mux->data.n_values; i++) {
	227	u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
	228	unsigned int class = mux->data.classes ? mux->data.classes[i] : 0;
92ed1a76	229
eee543e8 JD	230	mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr,
eee543e8 JD	231	i, class,
e7065e20	232	i2c_mux_gpio_select, deselect);
92ed1a76 PK	233	if (!mux->adap[i]) {
	234	ret = -ENODEV;
	235	dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
	236	goto add_adapter_failed;
	237	}
	238	}
	239
	240	dev_info(&pdev->dev, "%d port mux on %s adapter\n",
9b7a0c40	241	mux->data.n_values, parent->name);
92ed1a76 PK	242
	243	return 0;
	244
	245	add_adapter_failed:
	246	for (; i > 0; i--)
	247	i2c_del_mux_adapter(mux->adap[i - 1]);
9b7a0c40	248	i = mux->data.n_gpios;
92ed1a76 PK	249	err_request_gpio:
92ed1a76 PK	250	for (; i > 0; i--)
9b7a0c40	251	gpio_free(gpio_base + mux->data.gpios[i - 1]);
92ed1a76 PK	252	alloc_failed:
	253	i2c_put_adapter(parent);
	254
	255	return ret;
	256	}
	257
0b255e92	258	static int i2c_mux_gpio_remove(struct platform_device *pdev)
92ed1a76 PK	259	{
	260	struct gpiomux *mux = platform_get_drvdata(pdev);
	261	int i;
	262
	263	for (i = 0; i < mux->data.n_values; i++)
	264	i2c_del_mux_adapter(mux->adap[i]);
	265
	266	for (i = 0; i < mux->data.n_gpios; i++)
e7ee5140	267	gpio_free(mux->gpio_base + mux->data.gpios[i]);
92ed1a76	268
92ed1a76	269	i2c_put_adapter(mux->parent);
92ed1a76 PK	270
	271	return 0;
	272	}
	273
0b255e92	274	static const struct of_device_id i2c_mux_gpio_of_match[] = {
9b7a0c40 MR	275	{ .compatible = "i2c-mux-gpio", },
	276	{},
	277	};
	278	MODULE_DEVICE_TABLE(of, i2c_mux_gpio_of_match);
	279
e7065e20 JD	280	static struct platform_driver i2c_mux_gpio_driver = {
e7065e20 JD	281	.probe = i2c_mux_gpio_probe,
0b255e92	282	.remove = i2c_mux_gpio_remove,
92ed1a76 PK	283	.driver = {
92ed1a76 PK	284	.owner = THIS_MODULE,
e7065e20	285	.name = "i2c-mux-gpio",
9b7a0c40	286	.of_match_table = of_match_ptr(i2c_mux_gpio_of_match),
92ed1a76 PK	287	},
	288	};
	289
e7065e20	290	module_platform_driver(i2c_mux_gpio_driver);
92ed1a76 PK	291
	292	MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver");
	293	MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>");
	294	MODULE_LICENSE("GPL");
e7065e20	295	MODULE_ALIAS("platform:i2c-mux-gpio");