linux/drivers/i2c/i2c-core-of.c
Boris Brezillon da0086d018 i2c: Export of_i2c_get_board_info()
I3C busses have to know about all I2C devices connected on the I3C bus
to properly initialize the I3C master, and I2C frames can't be sent on
the bus until this initialization is done.

We can't let the I2C core parse the DT and instantiate I2C devices as
part of its i2c_add_adapter() procedure because, when done this way,
I2C devices are directly registered to the device-model and might be
attached to drivers which could in turn start sending frames on the bus,
which won't work since, as said above, the bus is not yet initialized.

Export of_i2c_register_device() in order to let the I3C core parse the
I2C device nodes by itself and initialize the bus.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2018-05-22 13:42:16 +02:00

278 lines
6.5 KiB
C

/*
* 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;
}
/* 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 */