include/linux/i2c-mux.h

   1 /*
   2  *
   3  * i2c-mux.h - functions for the i2c-bus mux support
   4  *
   5  * Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
   6  * Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
   7  * Michael Lawnick <michael.lawnick.ext@nsn.com>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  22  * MA 02110-1301 USA.
  23  */
  24
  25 #ifndef _LINUX_I2C_MUX_H
  26 #define _LINUX_I2C_MUX_H
  27
  28 #ifdef __KERNEL__
  29
  30 #include <linux/bitops.h>
  31
  32 struct i2c_mux_core {
  33         struct i2c_adapter *parent;
  34         struct device *dev;
  35         unsigned int mux_locked:1;
  36         unsigned int arbitrator:1;
  37         unsigned int gate:1;
  38
  39         void *priv;
  40
  41         int (*select)(struct i2c_mux_core *, u32 chan_id);
  42         int (*deselect)(struct i2c_mux_core *, u32 chan_id);
  43
  44         int num_adapters;
  45         int max_adapters;
  46         struct i2c_adapter *adapter[0];
  47 };
  48
  49 struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
  50                                    struct device *dev, int max_adapters,
  51                                    int sizeof_priv, u32 flags,
  52                                    int (*select)(struct i2c_mux_core *, u32),
  53                                    int (*deselect)(struct i2c_mux_core *, u32));
  54
  55 /* flags for i2c_mux_alloc */
  56 #define I2C_MUX_LOCKED     BIT(0)
  57 #define I2C_MUX_ARBITRATOR BIT(1)
  58 #define I2C_MUX_GATE       BIT(2)
  59
  60 static inline void *i2c_mux_priv(struct i2c_mux_core *muxc)
  61 {
  62         return muxc->priv;
  63 }
  64
  65 struct i2c_adapter *i2c_root_adapter(struct device *dev);
  66
  67 /*
  68  * Called to create an i2c bus on a multiplexed bus segment.
  69  * The chan_id parameter is passed to the select and deselect
  70  * callback functions to perform hardware-specific mux control.
  71  */
  72 int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
  73                         u32 force_nr, u32 chan_id,
  74                         unsigned int class);
  75
  76 void i2c_mux_del_adapters(struct i2c_mux_core *muxc);
  77
  78 #endif /* __KERNEL__ */
  79
  80 #endif /* _LINUX_I2C_MUX_H */