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Commit ea7513bb authored by Pantelis Antoniou's avatar Pantelis Antoniou Committed by Grant Likely
Browse files

i2c/of: Add OF_RECONFIG notifier handler 



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: default avatarPantelis Antoniou <pantelis.antoniou@konsulko.com>
[grant.likely: clean up #ifdefs and drop unneeded error handling]
Signed-off-by: default avatarGrant Likely <grant.likely@linaro.org>
Reviewed-by: default avatarWolfram Sang <wsa@the-dreams.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-i2c@vger.kernel.org
parent a430a345

drivers/i2c/i2c-core.c

+52 −0
Original line number Diff line number Diff line
@@ -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 @@ static int __init i2c_init(void) 


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);