drivers/i2c/muxes/i2c-demux-pinctrl.c - linux - Git at Google

 /*
  * 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");
	/*
	* 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");