/*
 * 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 Wolfram Sang <wsa@the-dreams.de>
 *
 * 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; either version 2 of the License, or (at your option)
 * any later version.
 */

#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 "i2c-core.h"

static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
                                                 struct device_node *node)
{
        struct i2c_client *result;
        struct i2c_board_info info = {};
        struct dev_archdata dev_ad = {};
        const __be32 *addr_be;
        u32 addr;
        int len;

        dev_dbg(&adap->dev, "of_i2c: register %pOF\n", node);

        if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
                dev_err(&adap->dev, "of_i2c: modalias failure on %pOF\n",
                        node);
                return ERR_PTR(-EINVAL);
        }

        addr_be = of_get_property(node, "reg", &len);
        if (!addr_be || (len < sizeof(*addr_be))) {
                dev_err(&adap->dev, "of_i2c: invalid reg on %pOF\n", node);
                return ERR_PTR(-EINVAL);
        }

        addr = be32_to_cpup(addr_be);
        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;
        }

        if (i2c_check_addr_validity(addr, info.flags)) {
                dev_err(&adap->dev, "of_i2c: invalid addr=%x on %pOF\n",
                        addr, node);
                return ERR_PTR(-EINVAL);
        }

        info.addr = addr;
        info.of_node = of_node_get(node);
        info.archdata = &dev_ad;

        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;

        result = i2c_new_device(adap, &info);
        if (result == NULL) {
                dev_err(&adap->dev, "of_i2c: Failure registering %pOF\n", node);
                of_node_put(node);
                return ERR_PTR(-EINVAL);
        }
        return result;
}

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_warn(&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_node_match(struct device *dev, void *data)
{
        return dev->of_node == data;
}

/* 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(&i2c_bus_type, NULL, node, of_dev_node_match);
        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_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);
                put_device(&adap->dev);

                if (IS_ERR(client)) {
                        dev_err(&adap->dev, "failed to create client for '%pOF'\n",
                                 rd->dn);
                        of_node_clear_flag(rd->dn, OF_POPULATED);
                        return notifier_from_errno(PTR_ERR(client));
                }
                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 */