[mirror_ubuntu-zesty-kernel.git] / drivers / i2c / muxes / i2c-demux-pinctrl.c

/*
 * Pinctrl based I2C DeMultiplexer
 *
 * Copyright (C) 2015-16 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
 * Copyright (C) 2015-16 by Renesas Electronics Corporation
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; version 2 of the License.
 *
 * See the bindings doc for DTS setup and the sysfs doc for usage information.
 * (look for filenames containing 'i2c-demux-pinctrl' in Documentation/)
 */

#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/sysfs.h>

struct i2c_demux_pinctrl_chan {
	struct device_node *parent_np;
	struct i2c_adapter *parent_adap;
	struct of_changeset chgset;
};

struct i2c_demux_pinctrl_priv {
	int cur_chan;
	int num_chan;
	struct device *dev;
	const char *bus_name;
	struct i2c_adapter cur_adap;
	struct i2c_algorithm algo;
	struct i2c_demux_pinctrl_chan chan[];
};

static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;

	return __i2c_transfer(parent, msgs, num);
}

static u32 i2c_demux_functionality(struct i2c_adapter *adap)
{
	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;

	return parent->algo->functionality(parent);
}

static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
{
	struct i2c_adapter *adap;
	struct pinctrl *p;
	int ret;

	ret = of_changeset_apply(&priv->chan[new_chan].chgset);
	if (ret)
		goto err;

	adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
	if (!adap) {
		ret = -ENODEV;
		goto err_with_revert;
	}

	p = devm_pinctrl_get_select(adap->dev.parent, priv->bus_name);
	if (IS_ERR(p)) {
		ret = PTR_ERR(p);
		goto err_with_put;
	}

	priv->chan[new_chan].parent_adap = adap;
	priv->cur_chan = new_chan;

	/* Now fill out current adapter structure. cur_chan must be up to date */
	priv->algo.master_xfer = i2c_demux_master_xfer;
	priv->algo.functionality = i2c_demux_functionality;

	snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name),
		 "i2c-demux (master i2c-%d)", i2c_adapter_id(adap));
	priv->cur_adap.owner = THIS_MODULE;
	priv->cur_adap.algo = &priv->algo;
	priv->cur_adap.algo_data = priv;
	priv->cur_adap.dev.parent = priv->dev;
	priv->cur_adap.class = adap->class;
	priv->cur_adap.retries = adap->retries;
	priv->cur_adap.timeout = adap->timeout;
	priv->cur_adap.quirks = adap->quirks;
	priv->cur_adap.dev.of_node = priv->dev->of_node;
	ret = i2c_add_adapter(&priv->cur_adap);
	if (ret < 0)
		goto err_with_put;

	return 0;

 err_with_put:
	i2c_put_adapter(adap);
 err_with_revert:
	of_changeset_revert(&priv->chan[new_chan].chgset);
 err:
	dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret);
	priv->cur_chan = -EINVAL;
	return ret;
}

static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv)
{
	int ret, cur = priv->cur_chan;

	if (cur < 0)
		return 0;

	i2c_del_adapter(&priv->cur_adap);
	i2c_put_adapter(priv->chan[cur].parent_adap);

	ret = of_changeset_revert(&priv->chan[cur].chgset);

	priv->chan[cur].parent_adap = NULL;
	priv->cur_chan = -EINVAL;

	return ret;
}

static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
{
	int ret;

	if (new_chan == priv->cur_chan)
		return 0;

	ret = i2c_demux_deactivate_master(priv);
	if (ret)
		return ret;

	return i2c_demux_activate_master(priv, new_chan);
}

static ssize_t available_masters_show(struct device *dev,
				      struct device_attribute *attr,
				      char *buf)
{
	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	int count = 0, i;

	for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++)
		count += scnprintf(buf + count, PAGE_SIZE - count, "%d:%s%c",
				   i, priv->chan[i].parent_np->full_name,
				   i == priv->num_chan - 1 ? '\n' : ' ');

	return count;
}
static DEVICE_ATTR_RO(available_masters);

static ssize_t current_master_show(struct device *dev,
				   struct device_attribute *attr,
				   char *buf)
{
	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);

	return sprintf(buf, "%d\n", priv->cur_chan);
}

static ssize_t current_master_store(struct device *dev,
				    struct device_attribute *attr,
				    const char *buf, size_t count)
{
	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	unsigned int val;
	int ret;

	ret = kstrtouint(buf, 0, &val);
	if (ret < 0)
		return ret;

	if (val >= priv->num_chan)
		return -EINVAL;

	ret = i2c_demux_change_master(priv, val);

	return ret < 0 ? ret : count;
}
static DEVICE_ATTR_RW(current_master);

static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct i2c_demux_pinctrl_priv *priv;
	struct property *props;
	int num_chan, i, j, err;

	num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL);
	if (num_chan < 2) {
		dev_err(&pdev->dev, "Need at least two I2C masters to switch\n");
		return -EINVAL;
	}

	priv = devm_kzalloc(&pdev->dev, sizeof(*priv)
			   + num_chan * sizeof(struct i2c_demux_pinctrl_chan), GFP_KERNEL);

	props = devm_kcalloc(&pdev->dev, num_chan, sizeof(*props), GFP_KERNEL);

	if (!priv || !props)
		return -ENOMEM;

	err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name);
	if (err)
		return err;

	for (i = 0; i < num_chan; i++) {
		struct device_node *adap_np;

		adap_np = of_parse_phandle(np, "i2c-parent", i);
		if (!adap_np) {
			dev_err(&pdev->dev, "can't get phandle for parent %d\n", i);
			err = -ENOENT;
			goto err_rollback;
		}
		priv->chan[i].parent_np = adap_np;

		props[i].name = devm_kstrdup(&pdev->dev, "status", GFP_KERNEL);
		props[i].value = devm_kstrdup(&pdev->dev, "ok", GFP_KERNEL);
		props[i].length = 3;

		of_changeset_init(&priv->chan[i].chgset);
		of_changeset_update_property(&priv->chan[i].chgset, adap_np, &props[i]);
	}

	priv->num_chan = num_chan;
	priv->dev = &pdev->dev;

	platform_set_drvdata(pdev, priv);

	/* switch to first parent as active master */
	i2c_demux_activate_master(priv, 0);

	err = device_create_file(&pdev->dev, &dev_attr_available_masters);
	if (err)
		goto err_rollback;

	err = device_create_file(&pdev->dev, &dev_attr_current_master);
	if (err)
		goto err_rollback_available;

	return 0;

err_rollback_available:
	device_remove_file(&pdev->dev, &dev_attr_available_masters);
err_rollback:
	for (j = 0; j < i; j++) {
		of_node_put(priv->chan[j].parent_np);
		of_changeset_destroy(&priv->chan[j].chgset);
	}

	return err;
}

static int i2c_demux_pinctrl_remove(struct platform_device *pdev)
{
	struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev);
	int i;

	device_remove_file(&pdev->dev, &dev_attr_current_master);
	device_remove_file(&pdev->dev, &dev_attr_available_masters);

	i2c_demux_deactivate_master(priv);

	for (i = 0; i < priv->num_chan; i++) {
		of_node_put(priv->chan[i].parent_np);
		of_changeset_destroy(&priv->chan[i].chgset);
	}

	return 0;
}

static const struct of_device_id i2c_demux_pinctrl_of_match[] = {
	{ .compatible = "i2c-demux-pinctrl", },
	{},
};
MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match);

static struct platform_driver i2c_demux_pinctrl_driver = {
	.driver	= {
		.name = "i2c-demux-pinctrl",
		.of_match_table = i2c_demux_pinctrl_of_match,
	},
	.probe	= i2c_demux_pinctrl_probe,
	.remove	= i2c_demux_pinctrl_remove,
};
module_platform_driver(i2c_demux_pinctrl_driver);

MODULE_DESCRIPTION("pinctrl-based I2C demux driver");
MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:i2c-demux-pinctrl");
Commit	Line	Data
50a5ba87 WS	1	/*
	2	* Pinctrl based I2C DeMultiplexer
	3	*
	4	* Copyright (C) 2015-16 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com>
	5	* Copyright (C) 2015-16 by Renesas Electronics Corporation
	6	*
	7	* This program is free software; you can redistribute it and/or modify it
	8	* under the terms of the GNU General Public License as published by the
	9	* Free Software Foundation; version 2 of the License.
	10	*
	11	* See the bindings doc for DTS setup and the sysfs doc for usage information.
	12	* (look for filenames containing 'i2c-demux-pinctrl' in Documentation/)
	13	*/
	14
	15	#include <linux/i2c.h>
	16	#include <linux/init.h>
	17	#include <linux/module.h>
	18	#include <linux/of.h>
	19	#include <linux/pinctrl/consumer.h>
	20	#include <linux/platform_device.h>
	21	#include <linux/slab.h>
	22	#include <linux/sysfs.h>
	23
	24	struct i2c_demux_pinctrl_chan {
	25	struct device_node *parent_np;
	26	struct i2c_adapter *parent_adap;
	27	struct of_changeset chgset;
	28	};
	29
	30	struct i2c_demux_pinctrl_priv {
	31	int cur_chan;
	32	int num_chan;
	33	struct device *dev;
	34	const char *bus_name;
	35	struct i2c_adapter cur_adap;
	36	struct i2c_algorithm algo;
	37	struct i2c_demux_pinctrl_chan chan[];
	38	};
	39
50a5ba87 WS	40	static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
	41	{
	42	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
	43	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
	44
	45	return __i2c_transfer(parent, msgs, num);
	46	}
	47
	48	static u32 i2c_demux_functionality(struct i2c_adapter *adap)
	49	{
	50	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
	51	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
	52
	53	return parent->algo->functionality(parent);
	54	}
	55
	56	static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
	57	{
	58	struct i2c_adapter *adap;
	59	struct pinctrl *p;
	60	int ret;
	61
	62	ret = of_changeset_apply(&priv->chan[new_chan].chgset);
	63	if (ret)
	64	goto err;
	65
	66	adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
	67	if (!adap) {
	68	ret = -ENODEV;
ce8cb803	69	goto err_with_revert;
50a5ba87 WS	70	}
	71
	72	p = devm_pinctrl_get_select(adap->dev.parent, priv->bus_name);
	73	if (IS_ERR(p)) {
	74	ret = PTR_ERR(p);
	75	goto err_with_put;
	76	}
	77
	78	priv->chan[new_chan].parent_adap = adap;
	79	priv->cur_chan = new_chan;
	80
	81	/* Now fill out current adapter structure. cur_chan must be up to date */
	82	priv->algo.master_xfer = i2c_demux_master_xfer;
	83	priv->algo.functionality = i2c_demux_functionality;
	84
	85	snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name),
	86	"i2c-demux (master i2c-%d)", i2c_adapter_id(adap));
	87	priv->cur_adap.owner = THIS_MODULE;
	88	priv->cur_adap.algo = &priv->algo;
	89	priv->cur_adap.algo_data = priv;
	90	priv->cur_adap.dev.parent = priv->dev;
	91	priv->cur_adap.class = adap->class;
	92	priv->cur_adap.retries = adap->retries;
	93	priv->cur_adap.timeout = adap->timeout;
	94	priv->cur_adap.quirks = adap->quirks;
	95	priv->cur_adap.dev.of_node = priv->dev->of_node;
	96	ret = i2c_add_adapter(&priv->cur_adap);
	97	if (ret < 0)
	98	goto err_with_put;
	99
	100	return 0;
	101
	102	err_with_put:
	103	i2c_put_adapter(adap);
ce8cb803 WS	104	err_with_revert:
ce8cb803 WS	105	of_changeset_revert(&priv->chan[new_chan].chgset);
50a5ba87 WS	106	err:
50a5ba87 WS	107	dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret);
9a5382e8	108	priv->cur_chan = -EINVAL;
50a5ba87 WS	109	return ret;
	110	}
	111
	112	static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv)
	113	{
	114	int ret, cur = priv->cur_chan;
	115
	116	if (cur < 0)
	117	return 0;
	118
	119	i2c_del_adapter(&priv->cur_adap);
	120	i2c_put_adapter(priv->chan[cur].parent_adap);
	121
	122	ret = of_changeset_revert(&priv->chan[cur].chgset);
	123
	124	priv->chan[cur].parent_adap = NULL;
	125	priv->cur_chan = -EINVAL;
	126
	127	return ret;
	128	}
	129
	130	static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
	131	{
	132	int ret;
	133
	134	if (new_chan == priv->cur_chan)
	135	return 0;
	136
	137	ret = i2c_demux_deactivate_master(priv);
	138	if (ret)
	139	return ret;
	140
	141	return i2c_demux_activate_master(priv, new_chan);
	142	}
	143
c0c508a4 BH	144	static ssize_t available_masters_show(struct device *dev,
	145	struct device_attribute *attr,
	146	char *buf)
50a5ba87 WS	147	{
	148	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	149	int count = 0, i;
	150
	151	for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++)
c0c508a4 BH	152	count += scnprintf(buf + count, PAGE_SIZE - count, "%d:%s%c",
	153	i, priv->chan[i].parent_np->full_name,
	154	i == priv->num_chan - 1 ? '\n' : ' ');
50a5ba87 WS	155
	156	return count;
	157	}
c0c508a4	158	static DEVICE_ATTR_RO(available_masters);
50a5ba87	159
c0c508a4 BH	160	static ssize_t current_master_show(struct device *dev,
	161	struct device_attribute *attr,
	162	char *buf)
	163	{
	164	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	165
	166	return sprintf(buf, "%d\n", priv->cur_chan);
	167	}
	168
	169	static ssize_t current_master_store(struct device *dev,
	170	struct device_attribute *attr,
	171	const char *buf, size_t count)
50a5ba87 WS	172	{
	173	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	174	unsigned int val;
	175	int ret;
	176
	177	ret = kstrtouint(buf, 0, &val);
	178	if (ret < 0)
	179	return ret;
	180
	181	if (val >= priv->num_chan)
	182	return -EINVAL;
	183
	184	ret = i2c_demux_change_master(priv, val);
	185
	186	return ret < 0 ? ret : count;
	187	}
c0c508a4	188	static DEVICE_ATTR_RW(current_master);
50a5ba87 WS	189
	190	static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
	191	{
	192	struct device_node *np = pdev->dev.of_node;
	193	struct i2c_demux_pinctrl_priv *priv;
e35478ea	194	struct property *props;
50a5ba87 WS	195	int num_chan, i, j, err;
	196
	197	num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL);
	198	if (num_chan < 2) {
	199	dev_err(&pdev->dev, "Need at least two I2C masters to switch\n");
	200	return -EINVAL;
	201	}
	202
	203	priv = devm_kzalloc(&pdev->dev, sizeof(*priv)
	204	+ num_chan * sizeof(struct i2c_demux_pinctrl_chan), GFP_KERNEL);
e35478ea WS	205
	206	props = devm_kcalloc(&pdev->dev, num_chan, sizeof(*props), GFP_KERNEL);
	207
	208	if (!priv \|\| !props)
50a5ba87 WS	209	return -ENOMEM;
	210
	211	err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name);
	212	if (err)
	213	return err;
	214
	215	for (i = 0; i < num_chan; i++) {
	216	struct device_node *adap_np;
	217
	218	adap_np = of_parse_phandle(np, "i2c-parent", i);
	219	if (!adap_np) {
	220	dev_err(&pdev->dev, "can't get phandle for parent %d\n", i);
	221	err = -ENOENT;
	222	goto err_rollback;
	223	}
	224	priv->chan[i].parent_np = adap_np;
	225
e35478ea WS	226	props[i].name = devm_kstrdup(&pdev->dev, "status", GFP_KERNEL);
	227	props[i].value = devm_kstrdup(&pdev->dev, "ok", GFP_KERNEL);
	228	props[i].length = 3;
	229
50a5ba87	230	of_changeset_init(&priv->chan[i].chgset);
e35478ea	231	of_changeset_update_property(&priv->chan[i].chgset, adap_np, &props[i]);
50a5ba87 WS	232	}
	233
	234	priv->num_chan = num_chan;
	235	priv->dev = &pdev->dev;
	236
	237	platform_set_drvdata(pdev, priv);
	238
	239	/* switch to first parent as active master */
	240	i2c_demux_activate_master(priv, 0);
	241
c0c508a4	242	err = device_create_file(&pdev->dev, &dev_attr_available_masters);
50a5ba87 WS	243	if (err)
	244	goto err_rollback;
	245
c0c508a4 BH	246	err = device_create_file(&pdev->dev, &dev_attr_current_master);
	247	if (err)
	248	goto err_rollback_available;
	249
50a5ba87 WS	250	return 0;
50a5ba87 WS	251
c0c508a4 BH	252	err_rollback_available:
c0c508a4 BH	253	device_remove_file(&pdev->dev, &dev_attr_available_masters);
50a5ba87 WS	254	err_rollback:
	255	for (j = 0; j < i; j++) {
	256	of_node_put(priv->chan[j].parent_np);
	257	of_changeset_destroy(&priv->chan[j].chgset);
	258	}
	259
	260	return err;
	261	}
	262
	263	static int i2c_demux_pinctrl_remove(struct platform_device *pdev)
	264	{
	265	struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev);
	266	int i;
	267
c0c508a4 BH	268	device_remove_file(&pdev->dev, &dev_attr_current_master);
c0c508a4 BH	269	device_remove_file(&pdev->dev, &dev_attr_available_masters);
50a5ba87 WS	270
	271	i2c_demux_deactivate_master(priv);
	272
	273	for (i = 0; i < priv->num_chan; i++) {
	274	of_node_put(priv->chan[i].parent_np);
	275	of_changeset_destroy(&priv->chan[i].chgset);
	276	}
	277
	278	return 0;
	279	}
	280
	281	static const struct of_device_id i2c_demux_pinctrl_of_match[] = {
	282	{ .compatible = "i2c-demux-pinctrl", },
	283	{},
	284	};
	285	MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match);
	286
	287	static struct platform_driver i2c_demux_pinctrl_driver = {
	288	.driver = {
	289	.name = "i2c-demux-pinctrl",
	290	.of_match_table = i2c_demux_pinctrl_of_match,
	291	},
	292	.probe = i2c_demux_pinctrl_probe,
	293	.remove = i2c_demux_pinctrl_remove,
	294	};
	295	module_platform_driver(i2c_demux_pinctrl_driver);
	296
	297	MODULE_DESCRIPTION("pinctrl-based I2C demux driver");
	298	MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
	299	MODULE_LICENSE("GPL v2");
	300	MODULE_ALIAS("platform:i2c-demux-pinctrl");