[mirror_ubuntu-bionic-kernel.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;
	struct gpio_desc **gpios;
	int *values;
};

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

	for (i = 0; i < mux->data.n_gpios; i++)
		mux->values[i] = (val >> i) & 1;

	gpiod_set_array_value_cansleep(mux->data.n_gpios,
				       mux->gpios, mux->values);
}

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,
			     mux->data.n_gpios * sizeof(*mux->gpios) +
			     mux->data.n_gpios * sizeof(*mux->values), 0,
			     i2c_mux_gpio_select, NULL);
	if (!muxc) {
		ret = -ENOMEM;
		goto alloc_failed;
	}
	mux->gpios = muxc->priv;
	mux->values = (int *)(mux->gpios + mux->data.n_gpios);
	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;
		}

		gpio_desc = gpio_to_desc(gpio_base + mux->data.gpios[i]);
		mux->gpios[i] = gpio_desc;

		if (!muxc->mux_locked)
			continue;

		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)
			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;
feff5c0a PR	24	struct gpio_desc **gpios;
feff5c0a PR	25	int *values;
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++)
feff5c0a PR	33	mux->values[i] = (val >> i) & 1;
	34
	35	gpiod_set_array_value_cansleep(mux->data.n_gpios,
	36	mux->gpios, mux->values);
92ed1a76 PK	37	}
92ed1a76 PK	38
bb448147	39	static int i2c_mux_gpio_select(struct i2c_mux_core *muxc, u32 chan)
92ed1a76	40	{
bb448147	41	struct gpiomux *mux = i2c_mux_priv(muxc);
92ed1a76	42
8c0ec250	43	i2c_mux_gpio_set(mux, chan);
92ed1a76 PK	44
	45	return 0;
	46	}
	47
bb448147	48	static int i2c_mux_gpio_deselect(struct i2c_mux_core *muxc, u32 chan)
92ed1a76	49	{
bb448147	50	struct gpiomux *mux = i2c_mux_priv(muxc);
92ed1a76	51
e7065e20	52	i2c_mux_gpio_set(mux, mux->data.idle);
92ed1a76 PK	53
	54	return 0;
	55	}
	56
0b255e92	57	static int match_gpio_chip_by_label(struct gpio_chip *chip,
e7ee5140 JD	58	void *data)
	59	{
	60	return !strcmp(chip->label, data);
	61	}
	62
9b7a0c40	63	#ifdef CONFIG_OF
0b255e92	64	static int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
9b7a0c40 MR	65	struct platform_device *pdev)
	66	{
	67	struct device_node *np = pdev->dev.of_node;
	68	struct device_node adapter_np, child;
	69	struct i2c_adapter *adapter;
	70	unsigned values, gpios;
492ed77b	71	int i = 0, ret;
9b7a0c40 MR	72
	73	if (!np)
	74	return -ENODEV;
	75
	76	adapter_np = of_parse_phandle(np, "i2c-parent", 0);
	77	if (!adapter_np) {
	78	dev_err(&pdev->dev, "Cannot parse i2c-parent\n");
	79	return -ENODEV;
	80	}
	81	adapter = of_find_i2c_adapter_by_node(adapter_np);
bdbf4a29	82	of_node_put(adapter_np);
623e4ecb	83	if (!adapter)
9937b8d8	84	return -EPROBE_DEFER;
623e4ecb	85
9b7a0c40 MR	86	mux->data.parent = i2c_adapter_id(adapter);
	87	put_device(&adapter->dev);
	88
	89	mux->data.n_values = of_get_child_count(np);
	90
	91	values = devm_kzalloc(&pdev->dev,
	92	sizeof(mux->data.values) mux->data.n_values,
	93	GFP_KERNEL);
	94	if (!values) {
	95	dev_err(&pdev->dev, "Cannot allocate values array");
	96	return -ENOMEM;
	97	}
	98
	99	for_each_child_of_node(np, child) {
	100	of_property_read_u32(child, "reg", values + i);
	101	i++;
	102	}
	103	mux->data.values = values;
	104
	105	if (of_property_read_u32(np, "idle-state", &mux->data.idle))
	106	mux->data.idle = I2C_MUX_GPIO_NO_IDLE;
	107
	108	mux->data.n_gpios = of_gpio_named_count(np, "mux-gpios");
	109	if (mux->data.n_gpios < 0) {
	110	dev_err(&pdev->dev, "Missing mux-gpios property in the DT.\n");
	111	return -EINVAL;
	112	}
	113
	114	gpios = devm_kzalloc(&pdev->dev,
	115	sizeof(mux->data.gpios) mux->data.n_gpios, GFP_KERNEL);
	116	if (!gpios) {
	117	dev_err(&pdev->dev, "Cannot allocate gpios array");
	118	return -ENOMEM;
	119	}
	120
492ed77b IN	121	for (i = 0; i < mux->data.n_gpios; i++) {
	122	ret = of_get_named_gpio(np, "mux-gpios", i);
	123	if (ret < 0)
	124	return ret;
	125	gpios[i] = ret;
	126	}
9b7a0c40 MR	127
	128	mux->data.gpios = gpios;
	129
	130	return 0;
	131	}
	132	#else
0b255e92	133	static int i2c_mux_gpio_probe_dt(struct gpiomux *mux,
9b7a0c40 MR	134	struct platform_device *pdev)
	135	{
	136	return 0;
	137	}
	138	#endif
	139
0b255e92	140	static int i2c_mux_gpio_probe(struct platform_device *pdev)
92ed1a76	141	{
bb448147	142	struct i2c_mux_core *muxc;
92ed1a76	143	struct gpiomux *mux;
92ed1a76	144	struct i2c_adapter *parent;
6ef91fcc	145	struct i2c_adapter *root;
e7ee5140	146	unsigned initial_state, gpio_base;
92ed1a76 PK	147	int i, ret;
92ed1a76 PK	148
9b7a0c40	149	mux = devm_kzalloc(&pdev->dev, sizeof(*mux), GFP_KERNEL);
bb448147	150	if (!mux)
9b7a0c40	151	return -ENOMEM;
9b7a0c40	152
6d4028c6	153	if (!dev_get_platdata(&pdev->dev)) {
9b7a0c40 MR	154	ret = i2c_mux_gpio_probe_dt(mux, pdev);
	155	if (ret < 0)
	156	return ret;
6d4028c6 JH	157	} else {
	158	memcpy(&mux->data, dev_get_platdata(&pdev->dev),
	159	sizeof(mux->data));
	160	}
9b7a0c40	161
e7ee5140 JD	162	/*
	163	* If a GPIO chip name is provided, the GPIO pin numbers provided are
	164	* relative to its base GPIO number. Otherwise they are absolute.
	165	*/
9b7a0c40	166	if (mux->data.gpio_chip) {
e7ee5140 JD	167	struct gpio_chip *gpio;
e7ee5140 JD	168
9b7a0c40	169	gpio = gpiochip_find(mux->data.gpio_chip,
e7ee5140 JD	170	match_gpio_chip_by_label);
	171	if (!gpio)
	172	return -EPROBE_DEFER;
	173
	174	gpio_base = gpio->base;
	175	} else {
	176	gpio_base = 0;
	177	}
	178
9b7a0c40	179	parent = i2c_get_adapter(mux->data.parent);
623e4ecb	180	if (!parent)
9937b8d8	181	return -EPROBE_DEFER;
92ed1a76	182
feff5c0a PR	183	muxc = i2c_mux_alloc(parent, &pdev->dev, mux->data.n_values,
	184	mux->data.n_gpios * sizeof(*mux->gpios) +
	185	mux->data.n_gpios * sizeof(*mux->values), 0,
bb448147 PR	186	i2c_mux_gpio_select, NULL);
bb448147 PR	187	if (!muxc) {
92ed1a76	188	ret = -ENOMEM;
2614a859	189	goto alloc_failed;
92ed1a76	190	}
feff5c0a PR	191	mux->gpios = muxc->priv;
feff5c0a PR	192	mux->values = (int *)(mux->gpios + mux->data.n_gpios);
bb448147 PR	193	muxc->priv = mux;
	194
	195	platform_set_drvdata(pdev, muxc);
	196
6ef91fcc PR	197	root = i2c_root_adapter(&parent->dev);
	198
	199	muxc->mux_locked = true;
bb448147	200	mux->gpio_base = gpio_base;
92ed1a76	201
9b7a0c40 MR	202	if (mux->data.idle != I2C_MUX_GPIO_NO_IDLE) {
9b7a0c40 MR	203	initial_state = mux->data.idle;
bb448147	204	muxc->deselect = i2c_mux_gpio_deselect;
92ed1a76	205	} else {
9b7a0c40	206	initial_state = mux->data.values[0];
92ed1a76 PK	207	}
92ed1a76 PK	208
9b7a0c40	209	for (i = 0; i < mux->data.n_gpios; i++) {
6ef91fcc PR	210	struct device *gpio_dev;
	211	struct gpio_desc *gpio_desc;
	212
9b7a0c40	213	ret = gpio_request(gpio_base + mux->data.gpios[i], "i2c-mux-gpio");
7fafae66 JD	214	if (ret) {
	215	dev_err(&pdev->dev, "Failed to request GPIO %d\n",
	216	mux->data.gpios[i]);
92ed1a76	217	goto err_request_gpio;
7fafae66 JD	218	}
	219
	220	ret = gpio_direction_output(gpio_base + mux->data.gpios[i],
	221	initial_state & (1 << i));
	222	if (ret) {
	223	dev_err(&pdev->dev,
	224	"Failed to set direction of GPIO %d to output\n",
	225	mux->data.gpios[i]);
	226	i++; /* gpio_request above succeeded, so must free */
	227	goto err_request_gpio;
	228	}
6ef91fcc	229
feff5c0a PR	230	gpio_desc = gpio_to_desc(gpio_base + mux->data.gpios[i]);
	231	mux->gpios[i] = gpio_desc;
	232
6ef91fcc PR	233	if (!muxc->mux_locked)
	234	continue;
	235
6ef91fcc PR	236	gpio_dev = &gpio_desc->gdev->dev;
6ef91fcc PR	237	muxc->mux_locked = i2c_root_adapter(gpio_dev) == root;
92ed1a76 PK	238	}
92ed1a76 PK	239
6ef91fcc PR	240	if (muxc->mux_locked)
	241	dev_info(&pdev->dev, "mux-locked i2c mux\n");
	242
9b7a0c40 MR	243	for (i = 0; i < mux->data.n_values; i++) {
	244	u32 nr = mux->data.base_nr ? (mux->data.base_nr + i) : 0;
	245	unsigned int class = mux->data.classes ? mux->data.classes[i] : 0;
92ed1a76	246
bb448147	247	ret = i2c_mux_add_adapter(muxc, nr, mux->data.values[i], class);
1b00900f	248	if (ret)
92ed1a76	249	goto add_adapter_failed;
92ed1a76 PK	250	}
	251
	252	dev_info(&pdev->dev, "%d port mux on %s adapter\n",
9b7a0c40	253	mux->data.n_values, parent->name);
92ed1a76 PK	254
	255	return 0;
	256
	257	add_adapter_failed:
bb448147	258	i2c_mux_del_adapters(muxc);
9b7a0c40	259	i = mux->data.n_gpios;
92ed1a76 PK	260	err_request_gpio:
92ed1a76 PK	261	for (; i > 0; i--)
9b7a0c40	262	gpio_free(gpio_base + mux->data.gpios[i - 1]);
92ed1a76 PK	263	alloc_failed:
	264	i2c_put_adapter(parent);
	265
	266	return ret;
	267	}
	268
0b255e92	269	static int i2c_mux_gpio_remove(struct platform_device *pdev)
92ed1a76	270	{
bb448147 PR	271	struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
bb448147 PR	272	struct gpiomux *mux = i2c_mux_priv(muxc);
92ed1a76 PK	273	int i;
92ed1a76 PK	274
bb448147	275	i2c_mux_del_adapters(muxc);
92ed1a76 PK	276
92ed1a76 PK	277	for (i = 0; i < mux->data.n_gpios; i++)
e7ee5140	278	gpio_free(mux->gpio_base + mux->data.gpios[i]);
92ed1a76	279
bb448147	280	i2c_put_adapter(muxc->parent);
92ed1a76 PK	281
	282	return 0;
	283	}
	284
0b255e92	285	static const struct of_device_id i2c_mux_gpio_of_match[] = {
9b7a0c40 MR	286	{ .compatible = "i2c-mux-gpio", },
	287	{},
	288	};
	289	MODULE_DEVICE_TABLE(of, i2c_mux_gpio_of_match);
	290
e7065e20 JD	291	static struct platform_driver i2c_mux_gpio_driver = {
e7065e20 JD	292	.probe = i2c_mux_gpio_probe,
0b255e92	293	.remove = i2c_mux_gpio_remove,
92ed1a76	294	.driver = {
e7065e20	295	.name = "i2c-mux-gpio",
4e905323	296	.of_match_table = i2c_mux_gpio_of_match,
92ed1a76 PK	297	},
	298	};
	299
e7065e20	300	module_platform_driver(i2c_mux_gpio_driver);
92ed1a76 PK	301
	302	MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver");
	303	MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>");
	304	MODULE_LICENSE("GPL");
e7065e20	305	MODULE_ALIAS("platform:i2c-mux-gpio");