[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/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_cansleep(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, 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)
		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)
		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,
						   mux->data.values[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	= {
		.name	= "i2c-mux-gpio",
		.of_match_table = 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	14	#include <linux/platform_device.h>
92ed1a76 PK	15	#include <linux/module.h>
	16	#include <linux/slab.h>
	17	#include <linux/gpio.h>
9b7a0c40	18	#include <linux/of_gpio.h>
92ed1a76 PK	19
	20	struct gpiomux {
	21	struct i2c_adapter *parent;
	22	struct i2c_adapter *adap; / child busses */
e7065e20	23	struct i2c_mux_gpio_platform_data data;
e7ee5140	24	unsigned gpio_base;
92ed1a76 PK	25	};
92ed1a76 PK	26
e7065e20	27	static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val)
92ed1a76 PK	28	{
	29	int i;
	30
	31	for (i = 0; i < mux->data.n_gpios; i++)
250ad590 IN	32	gpio_set_value_cansleep(mux->gpio_base + mux->data.gpios[i],
250ad590 IN	33	val & (1 << i));
92ed1a76 PK	34	}
92ed1a76 PK	35
e7065e20	36	static int i2c_mux_gpio_select(struct i2c_adapter adap, void data, u32 chan)
92ed1a76 PK	37	{
	38	struct gpiomux *mux = data;
	39
8c0ec250	40	i2c_mux_gpio_set(mux, chan);
92ed1a76 PK	41
	42	return 0;
	43	}
	44
e7065e20	45	static int i2c_mux_gpio_deselect(struct i2c_adapter adap, void data, u32 chan)
92ed1a76 PK	46	{
	47	struct gpiomux *mux = data;
	48
e7065e20	49	i2c_mux_gpio_set(mux, mux->data.idle);
92ed1a76 PK	50
	51	return 0;
	52	}
	53
0b255e92	54	static int match_gpio_chip_by_label(struct gpio_chip *chip,
e7ee5140 JD	55	void *data)
	56	{
	57	return !strcmp(chip->label, data);
	58	}
	59
9b7a0c40	60	#ifdef CONFIG_OF
0b255e92	61	static int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
9b7a0c40 MR	62	struct platform_device *pdev)
	63	{
	64	struct device_node *np = pdev->dev.of_node;
	65	struct device_node adapter_np, child;
	66	struct i2c_adapter *adapter;
	67	unsigned values, gpios;
492ed77b	68	int i = 0, ret;
9b7a0c40 MR	69
	70	if (!np)
	71	return -ENODEV;
	72
	73	adapter_np = of_parse_phandle(np, "i2c-parent", 0);
	74	if (!adapter_np) {
	75	dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
	76	return -ENODEV;
	77	}
	78	adapter = of_find_i2c_adapter_by_node(adapter_np);
623e4ecb	79	if (!adapter)
9937b8d8	80	return -EPROBE_DEFER;
623e4ecb	81
9b7a0c40 MR	82	mux->data.parent = i2c_adapter_id(adapter);
	83	put_device(&adapter->dev);
	84
	85	mux->data.n_values = of_get_child_count(np);
	86
	87	values = devm_kzalloc(&pdev->dev,
	88	sizeof(mux->data.values) mux->data.n_values,
	89	GFP_KERNEL);
	90	if (!values) {
	91	dev_err(&pdev->dev, "Cannot allocate values array");
	92	return -ENOMEM;
	93	}
	94
	95	for_each_child_of_node(np, child) {
	96	of_property_read_u32(child, "reg", values + i);
	97	i++;
	98	}
	99	mux->data.values = values;
	100
	101	if (of_property_read_u32(np, "idle-state", &mux->data.idle))
	102	mux->data.idle = I2C_MUX_GPIO_NO_IDLE;
	103
	104	mux->data.n_gpios = of_gpio_named_count(np, "mux-gpios");
	105	if (mux->data.n_gpios < 0) {
	106	dev_err(&pdev->dev, "Missing mux-gpios property in the DT.\n");
	107	return -EINVAL;
	108	}
	109
	110	gpios = devm_kzalloc(&pdev->dev,
	111	sizeof(mux->data.gpios) mux->data.n_gpios, GFP_KERNEL);
	112	if (!gpios) {
	113	dev_err(&pdev->dev, "Cannot allocate gpios array");
	114	return -ENOMEM;
	115	}
	116
492ed77b IN	117	for (i = 0; i < mux->data.n_gpios; i++) {
	118	ret = of_get_named_gpio(np, "mux-gpios", i);
	119	if (ret < 0)
	120	return ret;
	121	gpios[i] = ret;
	122	}
9b7a0c40 MR	123
	124	mux->data.gpios = gpios;
	125
	126	return 0;
	127	}
	128	#else
0b255e92	129	static int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
9b7a0c40 MR	130	struct platform_device *pdev)
	131	{
	132	return 0;
	133	}
	134	#endif
	135
0b255e92	136	static int i2c_mux_gpio_probe(struct platform_device *pdev)
92ed1a76 PK	137	{
92ed1a76 PK	138	struct gpiomux *mux;
92ed1a76 PK	139	struct i2c_adapter *parent;
92ed1a76 PK	140	int (deselect) (struct i2c_adapter , void *, u32);
e7ee5140	141	unsigned initial_state, gpio_base;
92ed1a76 PK	142	int i, ret;
92ed1a76 PK	143
9b7a0c40 MR	144	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
	145	if (!mux) {
	146	dev_err(&pdev->dev, "Cannot allocate gpiomux structure");
	147	return -ENOMEM;
92ed1a76 PK	148	}
92ed1a76 PK	149
9b7a0c40 MR	150	platform_set_drvdata(pdev, mux);
9b7a0c40 MR	151
6d4028c6	152	if (!dev_get_platdata(&pdev->dev)) {
9b7a0c40 MR	153	ret = i2c_mux_gpio_probe_dt(mux, pdev);
	154	if (ret < 0)
	155	return ret;
6d4028c6 JH	156	} else {
	157	memcpy(&mux->data, dev_get_platdata(&pdev->dev),
	158	sizeof(mux->data));
	159	}
9b7a0c40	160
e7ee5140 JD	161	/*
	162	* If a GPIO chip name is provided, the GPIO pin numbers provided are
	163	* relative to its base GPIO number. Otherwise they are absolute.
	164	*/
9b7a0c40	165	if (mux->data.gpio_chip) {
e7ee5140 JD	166	struct gpio_chip *gpio;
e7ee5140 JD	167
9b7a0c40	168	gpio = gpiochip_find(mux->data.gpio_chip,
e7ee5140 JD	169	match_gpio_chip_by_label);
	170	if (!gpio)
	171	return -EPROBE_DEFER;
	172
	173	gpio_base = gpio->base;
	174	} else {
	175	gpio_base = 0;
	176	}
	177
9b7a0c40	178	parent = i2c_get_adapter(mux->data.parent);
623e4ecb	179	if (!parent)
9937b8d8	180	return -EPROBE_DEFER;
92ed1a76	181
92ed1a76	182	mux->parent = parent;
e7ee5140	183	mux->gpio_base = gpio_base;
9b7a0c40	184
2614a859	185	mux->adap = devm_kzalloc(&pdev->dev,
9b7a0c40	186	sizeof(mux->adap) mux->data.n_values,
2614a859	187	GFP_KERNEL);
92ed1a76	188	if (!mux->adap) {
9b7a0c40	189	dev_err(&pdev->dev, "Cannot allocate i2c_adapter structure");
92ed1a76	190	ret = -ENOMEM;
2614a859	191	goto alloc_failed;
92ed1a76 PK	192	}
92ed1a76 PK	193
9b7a0c40 MR	194	if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) {
9b7a0c40 MR	195	initial_state = mux->data.idle;
e7065e20	196	deselect = i2c_mux_gpio_deselect;
92ed1a76	197	} else {
9b7a0c40	198	initial_state = mux->data.values[0];
92ed1a76 PK	199	deselect = NULL;
	200	}
	201
9b7a0c40 MR	202	for (i = 0; i < mux->data.n_gpios; i++) {
9b7a0c40 MR	203	ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio");
7fafae66 JD	204	if (ret) {
	205	dev_err(&pdev->dev, "Failed to request GPIO %d\n",
	206	mux->data.gpios[i]);
92ed1a76	207	goto err_request_gpio;
7fafae66 JD	208	}
	209
	210	ret = gpio_direction_output(gpio_base + mux->data.gpios[i],
	211	initial_state & (1 << i));
	212	if (ret) {
	213	dev_err(&pdev->dev,
	214	"Failed to set direction of GPIO %d to output\n",
	215	mux->data.gpios[i]);
	216	i++; /* gpio_request above succeeded, so must free */
	217	goto err_request_gpio;
	218	}
92ed1a76 PK	219	}
92ed1a76 PK	220
9b7a0c40 MR	221	for (i = 0; i < mux->data.n_values; i++) {
	222	u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
	223	unsigned int class = mux->data.classes ? mux->data.classes[i] : 0;
92ed1a76	224
eee543e8	225	mux->adap[i] = i2c_add_mux_adapter(parent, &pdev->dev, mux, nr,
8c0ec250	226	mux->data.values[i], class,
e7065e20	227	i2c_mux_gpio_select, deselect);
92ed1a76 PK	228	if (!mux->adap[i]) {
	229	ret = -ENODEV;
	230	dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
	231	goto add_adapter_failed;
	232	}
	233	}
	234
	235	dev_info(&pdev->dev, "%d port mux on %s adapter\n",
9b7a0c40	236	mux->data.n_values, parent->name);
92ed1a76 PK	237
	238	return 0;
	239
	240	add_adapter_failed:
	241	for (; i > 0; i--)
	242	i2c_del_mux_adapter(mux->adap[i - 1]);
9b7a0c40	243	i = mux->data.n_gpios;
92ed1a76 PK	244	err_request_gpio:
92ed1a76 PK	245	for (; i > 0; i--)
9b7a0c40	246	gpio_free(gpio_base + mux->data.gpios[i - 1]);
92ed1a76 PK	247	alloc_failed:
	248	i2c_put_adapter(parent);
	249
	250	return ret;
	251	}
	252
0b255e92	253	static int i2c_mux_gpio_remove(struct platform_device *pdev)
92ed1a76 PK	254	{
	255	struct gpiomux *mux = platform_get_drvdata(pdev);
	256	int i;
	257
	258	for (i = 0; i < mux->data.n_values; i++)
	259	i2c_del_mux_adapter(mux->adap[i]);
	260
	261	for (i = 0; i < mux->data.n_gpios; i++)
e7ee5140	262	gpio_free(mux->gpio_base + mux->data.gpios[i]);
92ed1a76	263
92ed1a76	264	i2c_put_adapter(mux->parent);
92ed1a76 PK	265
	266	return 0;
	267	}
	268
0b255e92	269	static const struct of_device_id i2c_mux_gpio_of_match[] = {
9b7a0c40 MR	270	{ .compatible = "i2c-mux-gpio", },
	271	{},
	272	};
	273	MODULE_DEVICE_TABLE(of, i2c_mux_gpio_of_match);
	274
e7065e20 JD	275	static struct platform_driver i2c_mux_gpio_driver = {
e7065e20 JD	276	.probe = i2c_mux_gpio_probe,
0b255e92	277	.remove = i2c_mux_gpio_remove,
92ed1a76	278	.driver = {
e7065e20	279	.name = "i2c-mux-gpio",
4e905323	280	.of_match_table = i2c_mux_gpio_of_match,
92ed1a76 PK	281	},
	282	};
	283
e7065e20	284	module_platform_driver(i2c_mux_gpio_driver);
92ed1a76 PK	285
	286	MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver");
	287	MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>");
	288	MODULE_LICENSE("GPL");
e7065e20	289	MODULE_ALIAS("platform:i2c-mux-gpio");