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authorDavid Brownell <david-b@pacbell.net>2007-05-01 23:26:31 +0200
committerJean Delvare <khali@hyperion.delvare>2007-05-01 23:26:31 +0200
commit9c1600eda42e52796f49b36cf15b9debcfd09bea (patch)
treefe93f5924c7777cd5c3cc1ef6033dd2dfae542b5 /drivers/i2c/i2c-core.h
parent4298cfc3eb6110df989f784be516c6340c597a66 (diff)
downloadlinux-9c1600eda42e52796f49b36cf15b9debcfd09bea.tar.bz2
i2c: Add i2c_board_info and i2c_new_device()
This provides partial support for new-style I2C driver binding. It builds on "struct i2c_board_info" declarations that identify I2C devices on a given board. This is needed on systems with I2C devices that can't be fully probed and/or autoconfigured, such as many embedded Linux configurations where the way a given I2C device is wired may affect how it must be used. There are two models for declaring such devices: * LATE -- using a public function i2c_new_device(). This lets modules declare I2C devices found *AFTER* a given I2C adapter becomes available. For example, a PCI card could create adapters giving access to utility chips on that card, and this would be used to associate those chips with those adapters. * EARLY -- from arch_initcall() level code, using a non-exported function i2c_register_board_info(). This copies the declarations *BEFORE* such an i2c_adapter becomes available, arranging that i2c_new_device() will be called later when i2c-core registers the relevant i2c_adapter. For example, arch/.../.../board-*.c files would declare the I2C devices along with their platform data, and I2C devices would behave much like PNPACPI devices. (That is, both enumerate from board-specific tables.) To match the exported i2c_new_device(), the previously-private function i2c_unregister_device() is now exported. Pending later patches using these new APIs, this is effectively a NOP. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'drivers/i2c/i2c-core.h')
-rw-r--r--drivers/i2c/i2c-core.h31
1 files changed, 31 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-core.h b/drivers/i2c/i2c-core.h
new file mode 100644
index 000000000000..cd5bff874855
--- /dev/null
+++ b/drivers/i2c/i2c-core.h
@@ -0,0 +1,31 @@
+/*
+ * i2c-core.h - interfaces internal to the I2C framework
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+struct i2c_devinfo {
+ struct list_head list;
+ int busnum;
+ struct i2c_board_info board_info;
+};
+
+/* board_lock protects board_list and first_dynamic_bus_num.
+ * only i2c core components are allowed to use these symbols.
+ */
+extern struct mutex __i2c_board_lock;
+extern struct list_head __i2c_board_list;
+extern int __i2c_first_dynamic_bus_num;
+