[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 "../../gpio/gpiolib.h"
#include <linux/of_gpio.h>

struct gpiomux {
	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_mux_core *muxc, u32 chan)
{
	struct gpiomux *mux = i2c_mux_priv(muxc);

	i2c_mux_gpio_set(mux, chan);

	return 0;
}

static int i2c_mux_gpio_deselect(struct i2c_mux_core *muxc, u32 chan)
{
	struct gpiomux *mux = i2c_mux_priv(muxc);

	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);
	of_node_put(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 i2c_mux_core *muxc;
	struct gpiomux *mux;
	struct i2c_adapter *parent;
	struct i2c_adapter *root;
	unsigned initial_state, gpio_base;
	int i, ret;

	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
	if (!mux)
		return -ENOMEM;

	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;

	muxc = i2c_mux_alloc(parent, &pdev->dev, mux->data.n_values, 0, 0,
			     i2c_mux_gpio_select, NULL);
	if (!muxc) {
		ret = -ENOMEM;
		goto alloc_failed;
	}
	muxc->priv = mux;

	platform_set_drvdata(pdev, muxc);

	root = i2c_root_adapter(&parent->dev);

	muxc->mux_locked = true;
	mux->gpio_base = gpio_base;

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

	for (i = 0; i < mux->data.n_gpios; i++) {
		struct device *gpio_dev;
		struct gpio_desc *gpio_desc;

		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;
		}

		if (!muxc->mux_locked)
			continue;

		gpio_desc = gpio_to_desc(gpio_base + mux->data.gpios[i]);
		gpio_dev = &gpio_desc->gdev->dev;
		muxc->mux_locked = i2c_root_adapter(gpio_dev) == root;
	}

	if (muxc->mux_locked)
		dev_info(&pdev->dev, "mux-locked i2c mux\n");

	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;

		ret = i2c_mux_add_adapter(muxc, nr, mux->data.values[i], class);
		if (ret) {
			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:
	i2c_mux_del_adapters(muxc);
	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 i2c_mux_core *muxc = platform_get_drvdata(pdev);
	struct gpiomux *mux = i2c_mux_priv(muxc);
	int i;

	i2c_mux_del_adapters(muxc);

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

	i2c_put_adapter(muxc->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>
6ef91fcc	18	#include "../../gpio/gpiolib.h"
9b7a0c40	19	#include <linux/of_gpio.h>
92ed1a76 PK	20
92ed1a76 PK	21	struct gpiomux {
e7065e20	22	struct i2c_mux_gpio_platform_data data;
e7ee5140	23	unsigned gpio_base;
92ed1a76 PK	24	};
92ed1a76 PK	25
e7065e20	26	static void i2c_mux_gpio_set(const struct gpiomux *mux, unsigned val)
92ed1a76 PK	27	{
	28	int i;
	29
	30	for (i = 0; i < mux->data.n_gpios; i++)
250ad590 IN	31	gpio_set_value_cansleep(mux->gpio_base + mux->data.gpios[i],
250ad590 IN	32	val & (1 << i));
92ed1a76 PK	33	}
92ed1a76 PK	34
bb448147	35	static int i2c_mux_gpio_select(struct i2c_mux_core *muxc, u32 chan)
92ed1a76	36	{
bb448147	37	struct gpiomux *mux = i2c_mux_priv(muxc);
92ed1a76	38
8c0ec250	39	i2c_mux_gpio_set(mux, chan);
92ed1a76 PK	40
	41	return 0;
	42	}
	43
bb448147	44	static int i2c_mux_gpio_deselect(struct i2c_mux_core *muxc, u32 chan)
92ed1a76	45	{
bb448147	46	struct gpiomux *mux = i2c_mux_priv(muxc);
92ed1a76	47
e7065e20	48	i2c_mux_gpio_set(mux, mux->data.idle);
92ed1a76 PK	49
	50	return 0;
	51	}
	52
0b255e92	53	static int match_gpio_chip_by_label(struct gpio_chip *chip,
e7ee5140 JD	54	void *data)
	55	{
	56	return !strcmp(chip->label, data);
	57	}
	58
9b7a0c40	59	#ifdef CONFIG_OF
0b255e92	60	static int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
9b7a0c40 MR	61	struct platform_device *pdev)
	62	{
	63	struct device_node *np = pdev->dev.of_node;
	64	struct device_node adapter_np, child;
	65	struct i2c_adapter *adapter;
	66	unsigned values, gpios;
492ed77b	67	int i = 0, ret;
9b7a0c40 MR	68
	69	if (!np)
	70	return -ENODEV;
	71
	72	adapter_np = of_parse_phandle(np, "i2c-parent", 0);
	73	if (!adapter_np) {
	74	dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
	75	return -ENODEV;
	76	}
	77	adapter = of_find_i2c_adapter_by_node(adapter_np);
bdbf4a29	78	of_node_put(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	137	{
bb448147	138	struct i2c_mux_core *muxc;
92ed1a76	139	struct gpiomux *mux;
92ed1a76	140	struct i2c_adapter *parent;
6ef91fcc	141	struct i2c_adapter *root;
e7ee5140	142	unsigned initial_state, gpio_base;
92ed1a76 PK	143	int i, ret;
92ed1a76 PK	144
9b7a0c40	145	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
bb448147	146	if (!mux)
9b7a0c40	147	return -ENOMEM;
9b7a0c40	148
6d4028c6	149	if (!dev_get_platdata(&pdev->dev)) {
9b7a0c40 MR	150	ret = i2c_mux_gpio_probe_dt(mux, pdev);
	151	if (ret < 0)
	152	return ret;
6d4028c6 JH	153	} else {
	154	memcpy(&mux->data, dev_get_platdata(&pdev->dev),
	155	sizeof(mux->data));
	156	}
9b7a0c40	157
e7ee5140 JD	158	/*
	159	* If a GPIO chip name is provided, the GPIO pin numbers provided are
	160	* relative to its base GPIO number. Otherwise they are absolute.
	161	*/
9b7a0c40	162	if (mux->data.gpio_chip) {
e7ee5140 JD	163	struct gpio_chip *gpio;
e7ee5140 JD	164
9b7a0c40	165	gpio = gpiochip_find(mux->data.gpio_chip,
e7ee5140 JD	166	match_gpio_chip_by_label);
	167	if (!gpio)
	168	return -EPROBE_DEFER;
	169
	170	gpio_base = gpio->base;
	171	} else {
	172	gpio_base = 0;
	173	}
	174
9b7a0c40	175	parent = i2c_get_adapter(mux->data.parent);
623e4ecb	176	if (!parent)
9937b8d8	177	return -EPROBE_DEFER;
92ed1a76	178
bb448147 PR	179	muxc = i2c_mux_alloc(parent, &pdev->dev, mux->data.n_values, 0, 0,
	180	i2c_mux_gpio_select, NULL);
	181	if (!muxc) {
92ed1a76	182	ret = -ENOMEM;
2614a859	183	goto alloc_failed;
92ed1a76	184	}
bb448147 PR	185	muxc->priv = mux;
	186
	187	platform_set_drvdata(pdev, muxc);
	188
6ef91fcc PR	189	root = i2c_root_adapter(&parent->dev);
	190
	191	muxc->mux_locked = true;
bb448147	192	mux->gpio_base = gpio_base;
92ed1a76	193
9b7a0c40 MR	194	if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) {
9b7a0c40 MR	195	initial_state = mux->data.idle;
bb448147	196	muxc->deselect = i2c_mux_gpio_deselect;
92ed1a76	197	} else {
9b7a0c40	198	initial_state = mux->data.values[0];
92ed1a76 PK	199	}
92ed1a76 PK	200
9b7a0c40	201	for (i = 0; i < mux->data.n_gpios; i++) {
6ef91fcc PR	202	struct device *gpio_dev;
	203	struct gpio_desc *gpio_desc;
	204
9b7a0c40	205	ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio");
7fafae66 JD	206	if (ret) {
	207	dev_err(&pdev->dev, "Failed to request GPIO %d\n",
	208	mux->data.gpios[i]);
92ed1a76	209	goto err_request_gpio;
7fafae66 JD	210	}
	211
	212	ret = gpio_direction_output(gpio_base + mux->data.gpios[i],
	213	initial_state & (1 << i));
	214	if (ret) {
	215	dev_err(&pdev->dev,
	216	"Failed to set direction of GPIO %d to output\n",
	217	mux->data.gpios[i]);
	218	i++; /* gpio_request above succeeded, so must free */
	219	goto err_request_gpio;
	220	}
6ef91fcc PR	221
	222	if (!muxc->mux_locked)
	223	continue;
	224
	225	gpio_desc = gpio_to_desc(gpio_base + mux->data.gpios[i]);
	226	gpio_dev = &gpio_desc->gdev->dev;
	227	muxc->mux_locked = i2c_root_adapter(gpio_dev) == root;
92ed1a76 PK	228	}
92ed1a76 PK	229
6ef91fcc PR	230	if (muxc->mux_locked)
	231	dev_info(&pdev->dev, "mux-locked i2c mux\n");
	232
9b7a0c40 MR	233	for (i = 0; i < mux->data.n_values; i++) {
	234	u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
	235	unsigned int class = mux->data.classes ? mux->data.classes[i] : 0;
92ed1a76	236
bb448147 PR	237	ret = i2c_mux_add_adapter(muxc, nr, mux->data.values[i], class);
bb448147 PR	238	if (ret) {
92ed1a76 PK	239	dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
	240	goto add_adapter_failed;
	241	}
	242	}
	243
	244	dev_info(&pdev->dev, "%d port mux on %s adapter\n",
9b7a0c40	245	mux->data.n_values, parent->name);
92ed1a76 PK	246
	247	return 0;
	248
	249	add_adapter_failed:
bb448147	250	i2c_mux_del_adapters(muxc);
9b7a0c40	251	i = mux->data.n_gpios;
92ed1a76 PK	252	err_request_gpio:
92ed1a76 PK	253	for (; i > 0; i--)
9b7a0c40	254	gpio_free(gpio_base + mux->data.gpios[i - 1]);
92ed1a76 PK	255	alloc_failed:
	256	i2c_put_adapter(parent);
	257
	258	return ret;
	259	}
	260
0b255e92	261	static int i2c_mux_gpio_remove(struct platform_device *pdev)
92ed1a76	262	{
bb448147 PR	263	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
bb448147 PR	264	struct gpiomux *mux = i2c_mux_priv(muxc);
92ed1a76 PK	265	int i;
92ed1a76 PK	266
bb448147	267	i2c_mux_del_adapters(muxc);
92ed1a76 PK	268
92ed1a76 PK	269	for (i = 0; i < mux->data.n_gpios; i++)
e7ee5140	270	gpio_free(mux->gpio_base + mux->data.gpios[i]);
92ed1a76	271
bb448147	272	i2c_put_adapter(muxc->parent);
92ed1a76 PK	273
	274	return 0;
	275	}
	276
0b255e92	277	static const struct of_device_id i2c_mux_gpio_of_match[] = {
9b7a0c40 MR	278	{ .compatible = "i2c-mux-gpio", },
	279	{},
	280	};
	281	MODULE_DEVICE_TABLE(of, i2c_mux_gpio_of_match);
	282
e7065e20 JD	283	static struct platform_driver i2c_mux_gpio_driver = {
e7065e20 JD	284	.probe = i2c_mux_gpio_probe,
0b255e92	285	.remove = i2c_mux_gpio_remove,
92ed1a76	286	.driver = {
e7065e20	287	.name = "i2c-mux-gpio",
4e905323	288	.of_match_table = i2c_mux_gpio_of_match,
92ed1a76 PK	289	},
	290	};
	291
e7065e20	292	module_platform_driver(i2c_mux_gpio_driver);
92ed1a76 PK	293
	294	MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver");
	295	MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>");
	296	MODULE_LICENSE("GPL");
e7065e20	297	MODULE_ALIAS("platform:i2c-mux-gpio");