diff options
Diffstat (limited to 'drivers/i2c/i2c-boardinfo.c')
| -rw-r--r-- | drivers/i2c/i2c-boardinfo.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/drivers/i2c/i2c-boardinfo.c b/drivers/i2c/i2c-boardinfo.c new file mode 100644 index 000000000000..ffb35f09df03 --- /dev/null +++ b/drivers/i2c/i2c-boardinfo.c @@ -0,0 +1,90 @@ +/* + * i2c-boardinfo.h - collect pre-declarations of I2C devices + * + * 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. + */ + +#include <linux/kernel.h> +#include <linux/i2c.h> + +#include "i2c-core.h" + + +/* These symbols are exported ONLY FOR the i2c core. + * No other users will be supported. + */ +DEFINE_MUTEX(__i2c_board_lock); +EXPORT_SYMBOL_GPL(__i2c_board_lock); + +LIST_HEAD(__i2c_board_list); +EXPORT_SYMBOL_GPL(__i2c_board_list); + +int __i2c_first_dynamic_bus_num; +EXPORT_SYMBOL_GPL(__i2c_first_dynamic_bus_num); + + +/** + * i2c_register_board_info - statically declare I2C devices + * @busnum: identifies the bus to which these devices belong + * @info: vector of i2c device descriptors + * @len: how many descriptors in the vector; may be zero to reserve + * the specified bus number. + * + * Systems using the Linux I2C driver stack can declare tables of board info + * while they initialize. This should be done in board-specific init code + * near arch_initcall() time, or equivalent, before any I2C adapter driver is + * registered. For example, mainboard init code could define several devices, + * as could the init code for each daughtercard in a board stack. + * + * The I2C devices will be created later, after the adapter for the relevant + * bus has been registered. After that moment, standard driver model tools + * are used to bind "new style" I2C drivers to the devices. The bus number + * for any device declared using this routine is not available for dynamic + * allocation. + * + * The board info passed can safely be __initdata, but be careful of embedded + * pointers (for platform_data, functions, etc) since that won't be copied. + */ +int __init +i2c_register_board_info(int busnum, + struct i2c_board_info const *info, unsigned len) +{ + int status; + + mutex_lock(&__i2c_board_lock); + + /* dynamic bus numbers will be assigned after the last static one */ + if (busnum >= __i2c_first_dynamic_bus_num) + __i2c_first_dynamic_bus_num = busnum + 1; + + for (status = 0; len; len--, info++) { + struct i2c_devinfo *devinfo; + + devinfo = kzalloc(sizeof(*devinfo), GFP_KERNEL); + if (!devinfo) { + pr_debug("i2c-core: can't register boardinfo!\n"); + status = -ENOMEM; + break; + } + + devinfo->busnum = busnum; + devinfo->board_info = *info; + list_add_tail(&devinfo->list, &__i2c_board_list); + } + + mutex_unlock(&__i2c_board_lock); + + return status; +} |