firmware/export/generic_i2c.h

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2006 by Linus Nielsen Feltzing
  11  *
  12  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19 #ifndef _GEN_I2C_
  20 #define _GEN_I2C_
  21
  22 struct i2c_interface
  23 {
  24     unsigned char address; /* Address of the chip that this interface
  25                               describes */
  26
  27     void (*scl_hi)(void);  /* Drive SCL high, might sleep on clk stretch */
  28     void (*scl_lo)(void);  /* Drive SCL low */
  29     void (*sda_hi)(void);  /* Drive SDA high */
  30     void (*sda_lo)(void);  /* Drive SDA low */
  31     void (*sda_input)(void);  /* Set SDA as input */
  32     void (*sda_output)(void); /* Set SDA as output */
  33     void (*scl_input)(void);  /* Set SCL as input */
  34     void (*scl_output)(void); /* Set SCL as output */
  35     int (*scl)(void);      /* Read SCL, returns 0 or non-zero */
  36     int (*sda)(void);      /* Read SDA, returns 0 or non-zero */
  37
  38     /* These are the delays specified in the I2C specification, the
  39        time pairs to the right are the minimum 100kHz and 400kHz specs */
  40     void (*delay_hd_sta)(void); /* START SDA hold (tHD:SDA)    4.0us/0.6us */
  41     void (*delay_hd_dat)(void); /* SDA hold (tHD:DAT)          5.0us/0us   */
  42     void (*delay_su_dat)(void); /* SDA setup (tSU:DAT)         250ns/100ns */
  43     void (*delay_su_sto)(void); /* STOP setup (tSU:STO)        4.0us/0.6us */
  44     void (*delay_su_sta)(void); /* Rep. START setup (tSU:STA)  4.7us/0.6us */
  45     void (*delay_thigh)(void);  /* SCL high period (tHIGH)     4.0us/0.6us */
  46 };
  47
  48 extern void i2c_add_node(struct i2c_interface *iface);
  49 extern int i2c_write_data(int bus_address, int address,
  50                           const unsigned char* buf, int count);
  51 extern int i2c_read_data(int bus_address, int address,
  52                          unsigned char* buf, int count);
  53 #endif