From ea7513bbc04170f1cbf42953187a4d8b731c71c4 Mon Sep 17 00:00:00 2001 From: Pantelis Antoniou Date: Tue, 28 Oct 2014 22:36:03 +0200 Subject: [PATCH] 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: Pantelis Antoniou [grant.likely: clean up #ifdefs and drop unneeded error handling] Signed-off-by: Grant Likely Reviewed-by: Wolfram Sang Cc: Rob Herring Cc: linux-i2c@vger.kernel.org --- 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 @@ 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); -- GitLab