1 files changed, 289 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core-of.c b/drivers/i2c/i2c-core-of.c
new file mode 100644
index 000000000..14d488499
--- /dev/null
+++ b/drivers/i2c/i2c-core-of.c
@@ -0,0 +1,289 @@
+/*
+ * 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>
+ *
+ * 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"
+
+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_node_match(struct device *dev, void *data)
+{
+	return dev->of_node == data;
+}
+
+static int of_dev_or_parent_node_match(struct device *dev, 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(&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_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 */