From: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
CONFIG_OF_DYNAMIC enables runtime changes to the device tree which in
turn may trigger addition or removal of devices from Linux. Add an
OF_RECONFIG notifier handler to receive tree change events and to
creating or destroy i2c devices as required.
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@xxxxxxxxxxxx>
[grant.likely: clean up #ifdefs and drop unneeded error handling]
Signed-off-by: Grant Likely <grant.likely@xxxxxxxxxx>
Cc: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: linux-i2c@xxxxxxxxxxxxxxx
---
drivers/i2c/i2c-core.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 52 insertions(+)
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 15ba6185dba5..d8afd3f28ca4 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1951,6 +1951,52 @@ void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
}
EXPORT_SYMBOL(i2c_clients_command);
+#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 */
+
+ client = of_i2c_register_device(adap, rd->dn);
+ put_device(&adap->dev);
+
+ if (IS_ERR(client)) {
+ pr_err("%s: failed to create for '%s'\n",
+ __func__, rd->dn->full_name);
+ return notifier_from_errno(PTR_ERR(client));
+ }
+ break;
+ case OF_RECONFIG_CHANGE_REMOVE:
+ /* 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;
+}
+static struct notifier_block i2c_of_notifier = {
+ .notifier_call = of_i2c_notify,
+};
+#else
+extern struct notifier_block i2c_of_notifier;
+#endif /* CONFIG_OF_DYNAMIC */
+
static int __init i2c_init(void)
{
int retval;
@@ -1968,6 +2014,10 @@ static int __init i2c_init(void)
retval = i2c_add_driver(&dummy_driver);
if (retval)
goto class_err;
+
+ if (IS_ENABLED(CONFIG_OF_DYNAMIC))
+ WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
+
return 0;
class_err:
@@ -1981,6 +2031,8 @@ bus_err:
static void __exit i2c_exit(void)
{
+ if (IS_ENABLED(CONFIG_OF_DYNAMIC))
+ WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
i2c_del_driver(&dummy_driver);
#ifdef CONFIG_I2C_COMPAT
class_compat_unregister(i2c_adapter_compat_class);
--
1.9.1
--
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