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author | David Brownell <david-b@pacbell.net> | 2007-05-01 23:26:31 +0200 |
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committer | Jean Delvare <khali@hyperion.delvare> | 2007-05-01 23:26:31 +0200 |
commit | 9c1600eda42e52796f49b36cf15b9debcfd09bea (patch) | |
tree | fe93f5924c7777cd5c3cc1ef6033dd2dfae542b5 /drivers/i2c/i2c-core.h | |
parent | 4298cfc3eb6110df989f784be516c6340c597a66 (diff) | |
download | kernel_samsung_smdk4412-9c1600eda42e52796f49b36cf15b9debcfd09bea.zip kernel_samsung_smdk4412-9c1600eda42e52796f49b36cf15b9debcfd09bea.tar.gz kernel_samsung_smdk4412-9c1600eda42e52796f49b36cf15b9debcfd09bea.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.h | 31 |
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 0000000..cd5bff8 --- /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; + |