[linux-2.6-block.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/pm_runtime.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;
	}

	/*
	 * Check if there are pinctrl states at all. Note: we cant' use
	 * devm_pinctrl_get_select() because we need to distinguish between
	 * the -ENODEV from devm_pinctrl_get() and pinctrl_lookup_state().
	 */
	p = devm_pinctrl_get(adap->dev.parent);
	if (IS_ERR(p)) {
		ret = PTR_ERR(p);
		/* continue if just no pinctrl states (e.g. i2c-gpio), otherwise exit */
		if (ret != -ENODEV)
			goto err_with_put;
	} else {
		/* there are states. check and use them */
		struct pinctrl_state *s = pinctrl_lookup_state(p, priv->bus_name);

		if (IS_ERR(s)) {
			ret = PTR_ERR(s);
			goto err_with_put;
		}
		ret = pinctrl_select_state(p, s);
		if (ret < 0)
			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 = &adap->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:%pOF%c",
				   i, priv->chan[i].parent_np,
				   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);

	pm_runtime_no_callbacks(&pdev->dev);

	/* 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>
fca700d6	21	#include <linux/pm_runtime.h>
50a5ba87 WS	22	#include <linux/slab.h>
	23	#include <linux/sysfs.h>
	24
	25	struct i2c_demux_pinctrl_chan {
	26	struct device_node *parent_np;
	27	struct i2c_adapter *parent_adap;
	28	struct of_changeset chgset;
	29	};
	30
	31	struct i2c_demux_pinctrl_priv {
	32	int cur_chan;
	33	int num_chan;
	34	struct device *dev;
	35	const char *bus_name;
	36	struct i2c_adapter cur_adap;
	37	struct i2c_algorithm algo;
	38	struct i2c_demux_pinctrl_chan chan[];
	39	};
	40
50a5ba87 WS	41	static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
	42	{
	43	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
	44	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
	45
	46	return __i2c_transfer(parent, msgs, num);
	47	}
	48
	49	static u32 i2c_demux_functionality(struct i2c_adapter *adap)
	50	{
	51	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
	52	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
	53
	54	return parent->algo->functionality(parent);
	55	}
	56
	57	static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
	58	{
	59	struct i2c_adapter *adap;
	60	struct pinctrl *p;
	61	int ret;
	62
	63	ret = of_changeset_apply(&priv->chan[new_chan].chgset);
	64	if (ret)
	65	goto err;
	66
	67	adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
	68	if (!adap) {
	69	ret = -ENODEV;
ce8cb803	70	goto err_with_revert;
50a5ba87 WS	71	}
50a5ba87 WS	72
d052db11 WS	73	/*
	74	* Check if there are pinctrl states at all. Note: we cant' use
	75	* devm_pinctrl_get_select() because we need to distinguish between
	76	* the -ENODEV from devm_pinctrl_get() and pinctrl_lookup_state().
	77	*/
	78	p = devm_pinctrl_get(adap->dev.parent);
50a5ba87 WS	79	if (IS_ERR(p)) {
50a5ba87 WS	80	ret = PTR_ERR(p);
d052db11 WS	81	/* continue if just no pinctrl states (e.g. i2c-gpio), otherwise exit */
	82	if (ret != -ENODEV)
	83	goto err_with_put;
	84	} else {
	85	/* there are states. check and use them */
	86	struct pinctrl_state *s = pinctrl_lookup_state(p, priv->bus_name);
	87
	88	if (IS_ERR(s)) {
	89	ret = PTR_ERR(s);
	90	goto err_with_put;
	91	}
	92	ret = pinctrl_select_state(p, s);
	93	if (ret < 0)
	94	goto err_with_put;
50a5ba87 WS	95	}
	96
	97	priv->chan[new_chan].parent_adap = adap;
	98	priv->cur_chan = new_chan;
	99
	100	/* Now fill out current adapter structure. cur_chan must be up to date */
	101	priv->algo.master_xfer = i2c_demux_master_xfer;
	102	priv->algo.functionality = i2c_demux_functionality;
	103
	104	snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name),
	105	"i2c-demux (master i2c-%d)", i2c_adapter_id(adap));
	106	priv->cur_adap.owner = THIS_MODULE;
	107	priv->cur_adap.algo = &priv->algo;
	108	priv->cur_adap.algo_data = priv;
5a9dcd81	109	priv->cur_adap.dev.parent = &adap->dev;
50a5ba87 WS	110	priv->cur_adap.class = adap->class;
	111	priv->cur_adap.retries = adap->retries;
	112	priv->cur_adap.timeout = adap->timeout;
	113	priv->cur_adap.quirks = adap->quirks;
	114	priv->cur_adap.dev.of_node = priv->dev->of_node;
	115	ret = i2c_add_adapter(&priv->cur_adap);
	116	if (ret < 0)
	117	goto err_with_put;
	118
	119	return 0;
	120
	121	err_with_put:
	122	i2c_put_adapter(adap);
ce8cb803 WS	123	err_with_revert:
ce8cb803 WS	124	of_changeset_revert(&priv->chan[new_chan].chgset);
50a5ba87 WS	125	err:
50a5ba87 WS	126	dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret);
9a5382e8	127	priv->cur_chan = -EINVAL;
50a5ba87 WS	128	return ret;
	129	}
	130
	131	static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv)
	132	{
	133	int ret, cur = priv->cur_chan;
	134
	135	if (cur < 0)
	136	return 0;
	137
	138	i2c_del_adapter(&priv->cur_adap);
	139	i2c_put_adapter(priv->chan[cur].parent_adap);
	140
	141	ret = of_changeset_revert(&priv->chan[cur].chgset);
	142
	143	priv->chan[cur].parent_adap = NULL;
	144	priv->cur_chan = -EINVAL;
	145
	146	return ret;
	147	}
	148
	149	static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
	150	{
	151	int ret;
	152
	153	if (new_chan == priv->cur_chan)
	154	return 0;
	155
	156	ret = i2c_demux_deactivate_master(priv);
	157	if (ret)
	158	return ret;
	159
	160	return i2c_demux_activate_master(priv, new_chan);
	161	}
	162
c0c508a4 BH	163	static ssize_t available_masters_show(struct device *dev,
	164	struct device_attribute *attr,
	165	char *buf)
50a5ba87 WS	166	{
	167	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	168	int count = 0, i;
	169
	170	for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++)
453a237c RH	171	count += scnprintf(buf + count, PAGE_SIZE - count, "%d:%pOF%c",
453a237c RH	172	i, priv->chan[i].parent_np,
c0c508a4	173	i == priv->num_chan - 1 ? '\n' : ' ');
50a5ba87 WS	174
	175	return count;
	176	}
c0c508a4	177	static DEVICE_ATTR_RO(available_masters);
50a5ba87	178
c0c508a4 BH	179	static ssize_t current_master_show(struct device *dev,
	180	struct device_attribute *attr,
	181	char *buf)
	182	{
	183	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	184
	185	return sprintf(buf, "%d\n", priv->cur_chan);
	186	}
	187
	188	static ssize_t current_master_store(struct device *dev,
	189	struct device_attribute *attr,
	190	const char *buf, size_t count)
50a5ba87 WS	191	{
	192	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	193	unsigned int val;
	194	int ret;
	195
	196	ret = kstrtouint(buf, 0, &val);
	197	if (ret < 0)
	198	return ret;
	199
	200	if (val >= priv->num_chan)
	201	return -EINVAL;
	202
	203	ret = i2c_demux_change_master(priv, val);
	204
	205	return ret < 0 ? ret : count;
	206	}
c0c508a4	207	static DEVICE_ATTR_RW(current_master);
50a5ba87 WS	208
	209	static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
	210	{
	211	struct device_node *np = pdev->dev.of_node;
	212	struct i2c_demux_pinctrl_priv *priv;
e35478ea	213	struct property *props;
50a5ba87 WS	214	int num_chan, i, j, err;
	215
	216	num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL);
	217	if (num_chan < 2) {
	218	dev_err(&pdev->dev, "Need at least two I2C masters to switch\n");
	219	return -EINVAL;
	220	}
	221
	222	priv = devm_kzalloc(&pdev->dev, sizeof(*priv)
	223	+ num_chan * sizeof(struct i2c_demux_pinctrl_chan), GFP_KERNEL);
e35478ea WS	224
	225	props = devm_kcalloc(&pdev->dev, num_chan, sizeof(*props), GFP_KERNEL);
	226
	227	if (!priv \|\| !props)
50a5ba87 WS	228	return -ENOMEM;
	229
	230	err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name);
	231	if (err)
	232	return err;
	233
	234	for (i = 0; i < num_chan; i++) {
	235	struct device_node *adap_np;
	236
	237	adap_np = of_parse_phandle(np, "i2c-parent", i);
	238	if (!adap_np) {
	239	dev_err(&pdev->dev, "can't get phandle for parent %d\n", i);
	240	err = -ENOENT;
	241	goto err_rollback;
	242	}
	243	priv->chan[i].parent_np = adap_np;
	244
e35478ea WS	245	props[i].name = devm_kstrdup(&pdev->dev, "status", GFP_KERNEL);
	246	props[i].value = devm_kstrdup(&pdev->dev, "ok", GFP_KERNEL);
	247	props[i].length = 3;
	248
50a5ba87	249	of_changeset_init(&priv->chan[i].chgset);
e35478ea	250	of_changeset_update_property(&priv->chan[i].chgset, adap_np, &props[i]);
50a5ba87 WS	251	}
	252
	253	priv->num_chan = num_chan;
	254	priv->dev = &pdev->dev;
	255
	256	platform_set_drvdata(pdev, priv);
	257
fca700d6 WS	258	pm_runtime_no_callbacks(&pdev->dev);
fca700d6 WS	259
50a5ba87 WS	260	/* switch to first parent as active master */
	261	i2c_demux_activate_master(priv, 0);
	262
c0c508a4	263	err = device_create_file(&pdev->dev, &dev_attr_available_masters);
50a5ba87 WS	264	if (err)
	265	goto err_rollback;
	266
c0c508a4 BH	267	err = device_create_file(&pdev->dev, &dev_attr_current_master);
	268	if (err)
	269	goto err_rollback_available;
	270
50a5ba87 WS	271	return 0;
50a5ba87 WS	272
c0c508a4 BH	273	err_rollback_available:
c0c508a4 BH	274	device_remove_file(&pdev->dev, &dev_attr_available_masters);
50a5ba87 WS	275	err_rollback:
	276	for (j = 0; j < i; j++) {
	277	of_node_put(priv->chan[j].parent_np);
	278	of_changeset_destroy(&priv->chan[j].chgset);
	279	}
	280
	281	return err;
	282	}
	283
	284	static int i2c_demux_pinctrl_remove(struct platform_device *pdev)
	285	{
	286	struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev);
	287	int i;
	288
c0c508a4 BH	289	device_remove_file(&pdev->dev, &dev_attr_current_master);
c0c508a4 BH	290	device_remove_file(&pdev->dev, &dev_attr_available_masters);
50a5ba87 WS	291
	292	i2c_demux_deactivate_master(priv);
	293
	294	for (i = 0; i < priv->num_chan; i++) {
	295	of_node_put(priv->chan[i].parent_np);
	296	of_changeset_destroy(&priv->chan[i].chgset);
	297	}
	298
	299	return 0;
	300	}
	301
	302	static const struct of_device_id i2c_demux_pinctrl_of_match[] = {
	303	{ .compatible = "i2c-demux-pinctrl", },
	304	{},
	305	};
	306	MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match);
	307
	308	static struct platform_driver i2c_demux_pinctrl_driver = {
	309	.driver = {
	310	.name = "i2c-demux-pinctrl",
	311	.of_match_table = i2c_demux_pinctrl_of_match,
	312	},
	313	.probe = i2c_demux_pinctrl_probe,
	314	.remove = i2c_demux_pinctrl_remove,
	315	};
	316	module_platform_driver(i2c_demux_pinctrl_driver);
	317
	318	MODULE_DESCRIPTION("pinctrl-based I2C demux driver");
	319	MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
	320	MODULE_LICENSE("GPL v2");
	321	MODULE_ALIAS("platform:i2c-demux-pinctrl");