[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/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 struct property status_okay = { .name = "status", .length = 3, .value = "ok" };

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);
	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;
	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);
	if (!priv)
		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;

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

	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
	40	static struct property status_okay = { .name = "status", .length = 3, .value = "ok" };
	41
	42	static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
	43	{
	44	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
	45	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
	46
	47	return __i2c_transfer(parent, msgs, num);
	48	}
	49
	50	static u32 i2c_demux_functionality(struct i2c_adapter *adap)
	51	{
	52	struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
	53	struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
	54
	55	return parent->algo->functionality(parent);
	56	}
	57
	58	static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
	59	{
	60	struct i2c_adapter *adap;
	61	struct pinctrl *p;
	62	int ret;
	63
	64	ret = of_changeset_apply(&priv->chan[new_chan].chgset);
65	if (ret)
66	goto err;
67
68	adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
69	if (!adap) {
70	ret = -ENODEV;
ce8cb803	71	goto err_with_revert;
50a5ba87 WS	72	}
	73
	74	p = devm_pinctrl_get_select(adap->dev.parent, priv->bus_name);
	75	if (IS_ERR(p)) {
	76	ret = PTR_ERR(p);
	77	goto err_with_put;
	78	}
	79
	80	priv->chan[new_chan].parent_adap = adap;
	81	priv->cur_chan = new_chan;
	82
	83	/* Now fill out current adapter structure. cur_chan must be up to date */
	84	priv->algo.master_xfer = i2c_demux_master_xfer;
	85	priv->algo.functionality = i2c_demux_functionality;
	86
	87	snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name),
	88	"i2c-demux (master i2c-%d)", i2c_adapter_id(adap));
	89	priv->cur_adap.owner = THIS_MODULE;
	90	priv->cur_adap.algo = &priv->algo;
	91	priv->cur_adap.algo_data = priv;
	92	priv->cur_adap.dev.parent = priv->dev;
	93	priv->cur_adap.class = adap->class;
	94	priv->cur_adap.retries = adap->retries;
	95	priv->cur_adap.timeout = adap->timeout;
	96	priv->cur_adap.quirks = adap->quirks;
	97	priv->cur_adap.dev.of_node = priv->dev->of_node;
	98	ret = i2c_add_adapter(&priv->cur_adap);
	99	if (ret < 0)
	100	goto err_with_put;
	101
	102	return 0;
	103
	104	err_with_put:
	105	i2c_put_adapter(adap);
ce8cb803 WS	106	err_with_revert:
ce8cb803 WS	107	of_changeset_revert(&priv->chan[new_chan].chgset);
50a5ba87 WS	108	err:
	109	dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret);
	110	return ret;
	111	}
	112
	113	static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv)
	114	{
	115	int ret, cur = priv->cur_chan;
	116
	117	if (cur < 0)
	118	return 0;
	119
	120	i2c_del_adapter(&priv->cur_adap);
	121	i2c_put_adapter(priv->chan[cur].parent_adap);
	122
	123	ret = of_changeset_revert(&priv->chan[cur].chgset);
	124
	125	priv->chan[cur].parent_adap = NULL;
	126	priv->cur_chan = -EINVAL;
	127
	128	return ret;
	129	}
	130
	131	static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
	132	{
	133	int ret;
	134
	135	if (new_chan == priv->cur_chan)
	136	return 0;
	137
	138	ret = i2c_demux_deactivate_master(priv);
	139	if (ret)
	140	return ret;
	141
	142	return i2c_demux_activate_master(priv, new_chan);
	143	}
	144
c0c508a4 BH	145	static ssize_t available_masters_show(struct device *dev,
	146	struct device_attribute *attr,
	147	char *buf)
50a5ba87 WS	148	{
	149	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	150	int count = 0, i;
	151
	152	for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++)
c0c508a4 BH	153	count += scnprintf(buf + count, PAGE_SIZE - count, "%d:%s%c",
	154	i, priv->chan[i].parent_np->full_name,
	155	i == priv->num_chan - 1 ? '\n' : ' ');
50a5ba87 WS	156
	157	return count;
	158	}
c0c508a4	159	static DEVICE_ATTR_RO(available_masters);
50a5ba87	160
c0c508a4 BH	161	static ssize_t current_master_show(struct device *dev,
	162	struct device_attribute *attr,
	163	char *buf)
	164	{
	165	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	166
	167	return sprintf(buf, "%d\n", priv->cur_chan);
	168	}
	169
	170	static ssize_t current_master_store(struct device *dev,
	171	struct device_attribute *attr,
	172	const char *buf, size_t count)
50a5ba87 WS	173	{
	174	struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
	175	unsigned int val;
	176	int ret;
	177
	178	ret = kstrtouint(buf, 0, &val);
	179	if (ret < 0)
	180	return ret;
	181
	182	if (val >= priv->num_chan)
	183	return -EINVAL;
	184
	185	ret = i2c_demux_change_master(priv, val);
	186
	187	return ret < 0 ? ret : count;
	188	}
c0c508a4	189	static DEVICE_ATTR_RW(current_master);
50a5ba87 WS	190
	191	static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
	192	{
	193	struct device_node *np = pdev->dev.of_node;
	194	struct i2c_demux_pinctrl_priv *priv;
	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);
	205	if (!priv)
	206	return -ENOMEM;
	207
	208	err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name);
	209	if (err)
	210	return err;
	211
	212	for (i = 0; i < num_chan; i++) {
	213	struct device_node *adap_np;
	214
	215	adap_np = of_parse_phandle(np, "i2c-parent", i);
	216	if (!adap_np) {
	217	dev_err(&pdev->dev, "can't get phandle for parent %d\n", i);
	218	err = -ENOENT;
	219	goto err_rollback;
	220	}
	221	priv->chan[i].parent_np = adap_np;
	222
	223	of_changeset_init(&priv->chan[i].chgset);
	224	of_changeset_update_property(&priv->chan[i].chgset, adap_np, &status_okay);
	225	}
	226
	227	priv->num_chan = num_chan;
	228	priv->dev = &pdev->dev;
	229
	230	platform_set_drvdata(pdev, priv);
	231
	232	/* switch to first parent as active master */
	233	i2c_demux_activate_master(priv, 0);
	234
c0c508a4	235	err = device_create_file(&pdev->dev, &dev_attr_available_masters);
50a5ba87 WS	236	if (err)
	237	goto err_rollback;
	238
c0c508a4 BH	239	err = device_create_file(&pdev->dev, &dev_attr_current_master);
	240	if (err)
	241	goto err_rollback_available;
	242
50a5ba87 WS	243	return 0;
50a5ba87 WS	244
c0c508a4 BH	245	err_rollback_available:
c0c508a4 BH	246	device_remove_file(&pdev->dev, &dev_attr_available_masters);
50a5ba87 WS	247	err_rollback:
	248	for (j = 0; j < i; j++) {
	249	of_node_put(priv->chan[j].parent_np);
	250	of_changeset_destroy(&priv->chan[j].chgset);
	251	}
	252
	253	return err;
	254	}
	255
	256	static int i2c_demux_pinctrl_remove(struct platform_device *pdev)
	257	{
	258	struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev);
	259	int i;
	260
c0c508a4 BH	261	device_remove_file(&pdev->dev, &dev_attr_current_master);
c0c508a4 BH	262	device_remove_file(&pdev->dev, &dev_attr_available_masters);
50a5ba87 WS	263
	264	i2c_demux_deactivate_master(priv);
	265
	266	for (i = 0; i < priv->num_chan; i++) {
	267	of_node_put(priv->chan[i].parent_np);
	268	of_changeset_destroy(&priv->chan[i].chgset);
	269	}
	270
	271	return 0;
	272	}
	273
	274	static const struct of_device_id i2c_demux_pinctrl_of_match[] = {
	275	{ .compatible = "i2c-demux-pinctrl", },
	276	{},
	277	};
	278	MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match);
	279
	280	static struct platform_driver i2c_demux_pinctrl_driver = {
	281	.driver = {
	282	.name = "i2c-demux-pinctrl",
	283	.of_match_table = i2c_demux_pinctrl_of_match,
	284	},
	285	.probe = i2c_demux_pinctrl_probe,
	286	.remove = i2c_demux_pinctrl_remove,
	287	};
	288	module_platform_driver(i2c_demux_pinctrl_driver);
	289
	290	MODULE_DESCRIPTION("pinctrl-based I2C demux driver");
	291	MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
	292	MODULE_LICENSE("GPL v2");
	293	MODULE_ALIAS("platform:i2c-demux-pinctrl");