LXR linux/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
  32struct 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
  49struct 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
  60static inline void *i2c_mux_priv(struct i2c_mux_core *muxc)
  61{
  62        return muxc->priv;
  63}
  64
  65struct 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 */
  72int i2c_mux_add_adapter(struct i2c_mux_core *muxc,
  73                        u32 force_nr, u32 chan_id,
  74                        unsigned int class);
  75
  76void i2c_mux_del_adapters(struct i2c_mux_core *muxc);
  77
  78#endif /* __KERNEL__ */
  79
  80#endif /* _LINUX_I2C_MUX_H */
  81