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32 results

intel_dp_mst.c

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  • i2c-core-of.c 6.45 KiB
    // SPDX-License-Identifier: GPL-2.0-or-later
    /*
     * Linux I2C core OF support code
     *
     * Copyright (C) 2008 Jochen Friedrich <jochen@scram.de>
     * based on a previous patch from Jon Smirl <jonsmirl@gmail.com>
     *
     * Copyright (C) 2013, 2018 Wolfram Sang <wsa@the-dreams.de>
     */
    
    #include <dt-bindings/i2c/i2c.h>
    #include <linux/device.h>
    #include <linux/err.h>
    #include <linux/i2c.h>
    #include <linux/module.h>
    #include <linux/of.h>
    #include <linux/of_device.h>
    #include <linux/sysfs.h>
    
    #include "i2c-core.h"
    
    int of_i2c_get_board_info(struct device *dev, struct device_node *node,
    			  struct i2c_board_info *info)
    {
    	u32 addr;
    	int ret;
    
    	memset(info, 0, sizeof(*info));
    
    	if (of_modalias_node(node, info->type, sizeof(info->type)) < 0) {
    		dev_err(dev, "of_i2c: modalias failure on %pOF\n", node);
    		return -EINVAL;
    	}
    
    	ret = of_property_read_u32(node, "reg", &addr);
    	if (ret) {
    		dev_err(dev, "of_i2c: invalid reg on %pOF\n", node);
    		return ret;
    	}
    
    	if (addr & I2C_TEN_BIT_ADDRESS) {
    		addr &= ~I2C_TEN_BIT_ADDRESS;
    		info->flags |= I2C_CLIENT_TEN;
    	}
    
    	if (addr & I2C_OWN_SLAVE_ADDRESS) {
    		addr &= ~I2C_OWN_SLAVE_ADDRESS;
    		info->flags |= I2C_CLIENT_SLAVE;
    	}
    
    	info->addr = addr;
    	info->of_node = node;
    
    	if (of_property_read_bool(node, "host-notify"))
    		info->flags |= I2C_CLIENT_HOST_NOTIFY;
    
    	if (of_get_property(node, "wakeup-source", NULL))
    		info->flags |= I2C_CLIENT_WAKE;
    
    	return 0;
    }
    EXPORT_SYMBOL_GPL(of_i2c_get_board_info);
    
    static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
    						 struct device_node *node)
    {
    	struct i2c_client *client;
    	struct i2c_board_info info;
    	int ret;
    
    	dev_dbg(&adap->dev, "of_i2c: register %pOF\n", node);
    
    	ret = of_i2c_get_board_info(&adap->dev, node, &info);
    	if (ret)
    		return ERR_PTR(ret);
    
    	client = i2c_new_device(adap, &info);
    	if (!client) {
    		dev_err(&adap->dev, "of_i2c: Failure registering %pOF\n", node);
    		return ERR_PTR(-EINVAL);
    	}
    	return client;
    }
    
    void of_i2c_register_devices(struct i2c_adapter *adap)
    {
    	struct device_node *bus, *node;
    	struct i2c_client *client;
    
    	/* Only register child devices if the adapter has a node pointer set */
    	if (!adap->dev.of_node)
    		return;
    
    	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
    
    	bus = of_get_child_by_name(adap->dev.of_node, "i2c-bus");
    	if (!bus)
    		bus = of_node_get(adap->dev.of_node);
    
    	for_each_available_child_of_node(bus, node) {
    		if (of_node_test_and_set_flag(node, OF_POPULATED))
    			continue;
    
    		client = of_i2c_register_device(adap, node);
    		if (IS_ERR(client)) {
    			dev_err(&adap->dev,
    				 "Failed to create I2C device for %pOF\n",
    				 node);
    			of_node_clear_flag(node, OF_POPULATED);
    		}
    	}
    
    	of_node_put(bus);
    }
    
    static int of_dev_or_parent_node_match(struct device *dev, const void *data)
    {
    	if (dev->of_node == data)
    		return 1;
    
    	if (dev->parent)
    		return dev->parent->of_node == data;
    
    	return 0;
    }
    
    /* must call put_device() when done with returned i2c_client device */
    struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
    {
    	struct device *dev;
    	struct i2c_client *client;
    
    	dev = bus_find_device_by_of_node(&i2c_bus_type, node);
    	if (!dev)
    		return NULL;
    
    	client = i2c_verify_client(dev);
    	if (!client)
    		put_device(dev);
    
    	return client;
    }
    EXPORT_SYMBOL(of_find_i2c_device_by_node);
    
    /* must call put_device() when done with returned i2c_adapter device */
    struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
    {
    	struct device *dev;
    	struct i2c_adapter *adapter;
    
    	dev = bus_find_device(&i2c_bus_type, NULL, node,
    			      of_dev_or_parent_node_match);
    	if (!dev)
    		return NULL;
    
    	adapter = i2c_verify_adapter(dev);
    	if (!adapter)
    		put_device(dev);
    
    	return adapter;
    }
    EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
    
    /* must call i2c_put_adapter() when done with returned i2c_adapter device */
    struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
    {
    	struct i2c_adapter *adapter;
    
    	adapter = of_find_i2c_adapter_by_node(node);
    	if (!adapter)
    		return NULL;
    
    	if (!try_module_get(adapter->owner)) {
    		put_device(&adapter->dev);
    		adapter = NULL;
    	}
    
    	return adapter;
    }
    EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
    
    static const struct of_device_id*
    i2c_of_match_device_sysfs(const struct of_device_id *matches,
    				  struct i2c_client *client)
    {
    	const char *name;
    
    	for (; matches->compatible[0]; matches++) {
    		/*
    		 * Adding devices through the i2c sysfs interface provides us
    		 * a string to match which may be compatible with the device
    		 * tree compatible strings, however with no actual of_node the
    		 * of_match_device() will not match
    		 */
    		if (sysfs_streq(client->name, matches->compatible))
    			return matches;
    
    		name = strchr(matches->compatible, ',');
    		if (!name)
    			name = matches->compatible;
    		else
    			name++;
    
    		if (sysfs_streq(client->name, name))
    			return matches;
    	}
    
    	return NULL;
    }
    
    const struct of_device_id
    *i2c_of_match_device(const struct of_device_id *matches,
    		     struct i2c_client *client)
    {
    	const struct of_device_id *match;
    
    	if (!(client && matches))
    		return NULL;
    
    	match = of_match_device(matches, &client->dev);
    	if (match)
    		return match;
    
    	return i2c_of_match_device_sysfs(matches, client);
    }
    EXPORT_SYMBOL_GPL(i2c_of_match_device);
    
    #if IS_ENABLED(CONFIG_OF_DYNAMIC)
    static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
    			 void *arg)
    {
    	struct of_reconfig_data *rd = arg;
    	struct i2c_adapter *adap;
    	struct i2c_client *client;
    
    	switch (of_reconfig_get_state_change(action, rd)) {
    	case OF_RECONFIG_CHANGE_ADD:
    		adap = of_find_i2c_adapter_by_node(rd->dn->parent);
    		if (adap == NULL)
    			return NOTIFY_OK;	/* not for us */
    
    		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
    			put_device(&adap->dev);
    			return NOTIFY_OK;
    		}
    
    		client = of_i2c_register_device(adap, rd->dn);
    		if (IS_ERR(client)) {
    			dev_err(&adap->dev, "failed to create client for '%pOF'\n",
    				 rd->dn);
    			put_device(&adap->dev);
    			of_node_clear_flag(rd->dn, OF_POPULATED);
    			return notifier_from_errno(PTR_ERR(client));
    		}
    		put_device(&adap->dev);
    		break;
    	case OF_RECONFIG_CHANGE_REMOVE:
    		/* already depopulated? */
    		if (!of_node_check_flag(rd->dn, OF_POPULATED))
    			return NOTIFY_OK;
    
    		/* find our device by node */
    		client = of_find_i2c_device_by_node(rd->dn);
    		if (client == NULL)
    			return NOTIFY_OK;	/* no? not meant for us */
    
    		/* unregister takes one ref away */
    		i2c_unregister_device(client);
    
    		/* and put the reference of the find */
    		put_device(&client->dev);
    		break;
    	}
    
    	return NOTIFY_OK;
    }
    
    struct notifier_block i2c_of_notifier = {
    	.notifier_call = of_i2c_notify,
    };
    #endif /* CONFIG_OF_DYNAMIC */