include/i2c.h

   1 /*
   2  * (C) Copyright 2001
   3  * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  *
  23  * The original I2C interface was
  24  *   (C) 2000 by Paolo Scaffardi (arsenio@tin.it)
  25  *   AIRVENT SAM s.p.a - RIMINI(ITALY)
  26  * but has been changed substantially.
  27  */
  28
  29 #ifndef _I2C_H_
  30 #define _I2C_H_
  31
  32 /*
  33  * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
  34  *
  35  * The implementation MUST NOT use static or global variables if the
  36  * I2C routines are used to read SDRAM configuration information
  37  * because this is done before the memories are initialized. Limited
  38  * use of stack-based variables are OK (the initial stack size is
  39  * limited).
  40  *
  41  * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
  42  */
  43
  44 /*
  45  * Configuration items.
  46  */
  47 #define I2C_RXTX_LEN    128     /* maximum tx/rx buffer length */
  48
  49 #if defined(CONFIG_I2C_MULTI_BUS)
  50 #if !defined(CONFIG_SYS_MAX_I2C_BUS)
  51 #define CONFIG_SYS_MAX_I2C_BUS          2
  52 #endif
  53 #define I2C_GET_BUS()           i2c_get_bus_num()
  54 #define I2C_SET_BUS(a)          i2c_set_bus_num(a)
  55 #else
  56 #define CONFIG_SYS_MAX_I2C_BUS          1
  57 #define I2C_GET_BUS()           0
  58 #define I2C_SET_BUS(a)
  59 #endif
  60
  61 /* define the I2C bus number for RTC and DTT if not already done */
  62 #if !defined(CONFIG_SYS_RTC_BUS_NUM)
  63 #define CONFIG_SYS_RTC_BUS_NUM          0
  64 #endif
  65 #if !defined(CONFIG_SYS_DTT_BUS_NUM)
  66 #define CONFIG_SYS_DTT_BUS_NUM          0
  67 #endif
  68 #if !defined(CONFIG_SYS_SPD_BUS_NUM)
  69 #define CONFIG_SYS_SPD_BUS_NUM          0
  70 #endif
  71
  72 #ifndef I2C_SOFT_DECLARATIONS
  73 # if defined(CONFIG_MPC8260)
  74 #  define I2C_SOFT_DECLARATIONS volatile ioport_t *iop = ioport_addr((immap_t *)CONFIG_SYS_IMMR, I2C_PORT);
  75 # elif defined(CONFIG_8xx)
  76 #  define I2C_SOFT_DECLARATIONS volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR;
  77 # else
  78 #  define I2C_SOFT_DECLARATIONS
  79 # endif
  80 #endif
  81
  82 #ifdef CONFIG_8xx
  83 /* Set default value for the I2C bus speed on 8xx. In the
  84  * future, we'll define these in all 8xx board config files.
  85  */
  86 #ifndef CONFIG_SYS_I2C_SPEED
  87 #define CONFIG_SYS_I2C_SPEED    50000
  88 #endif
  89 #endif
  90
  91 /*
  92  * Many boards/controllers/drivers don't support an I2C slave interface so
  93  * provide a default slave address for them for use in common code.  A real
  94  * value for CONFIG_SYS_I2C_SLAVE should be defined for any board which does
  95  * support a slave interface.
  96  */
  97 #ifndef CONFIG_SYS_I2C_SLAVE
  98 #define CONFIG_SYS_I2C_SLAVE    0xfe
  99 #endif
 100
 101 /*
 102  * Initialization, must be called once on start up, may be called
 103  * repeatedly to change the speed and slave addresses.
 104  */
 105 void i2c_init(int speed, int slaveaddr);
 106 #ifdef CONFIG_SYS_I2C_INIT_BOARD
 107 void i2c_init_board(void);
 108 #endif
 109
 110 #if defined(CONFIG_I2C_MUX)
 111
 112 typedef struct _mux {
 113         uchar   chip;
 114         uchar   channel;
 115         char    *name;
 116         struct _mux     *next;
 117 } I2C_MUX;
 118
 119 typedef struct _mux_device {
 120         int     busid;
 121         I2C_MUX *mux;   /* List of muxes, to reach the device */
 122         struct _mux_device      *next;
 123 } I2C_MUX_DEVICE;
 124
 125 int     i2c_mux_add_device(I2C_MUX_DEVICE *dev);
 126
 127 I2C_MUX_DEVICE  *i2c_mux_search_device(int id);
 128 I2C_MUX_DEVICE *i2c_mux_ident_muxstring (uchar *buf);
 129 int i2x_mux_select_mux(int bus);
 130 int i2c_mux_ident_muxstring_f (uchar *buf);
 131 #endif
 132
 133 /*
 134  * Probe the given I2C chip address.  Returns 0 if a chip responded,
 135  * not 0 on failure.
 136  */
 137 int i2c_probe(uchar chip);
 138
 139 /*
 140  * Read/Write interface:
 141  *   chip:    I2C chip address, range 0..127
 142  *   addr:    Memory (register) address within the chip
 143  *   alen:    Number of bytes to use for addr (typically 1, 2 for larger
 144  *              memories, 0 for register type devices with only one
 145  *              register)
 146  *   buffer:  Where to read/write the data
 147  *   len:     How many bytes to read/write
 148  *
 149  *   Returns: 0 on success, not 0 on failure
 150  */
 151 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len);
 152 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len);
 153
 154 /*
 155  * Utility routines to read/write registers.
 156  */
 157 static inline u8 i2c_reg_read(u8 addr, u8 reg)
 158 {
 159         u8 buf;
 160
 161 #ifdef CONFIG_8xx
 162         /* MPC8xx needs this.  Maybe one day we can get rid of it. */
 163         i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 164 #endif
 165
 166 #ifdef DEBUG
 167         printf("%s: addr=0x%02x, reg=0x%02x\n", __func__, addr, reg);
 168 #endif
 169
 170         i2c_read(addr, reg, 1, &buf, 1);
 171
 172         return buf;
 173 }
 174
 175 static inline void i2c_reg_write(u8 addr, u8 reg, u8 val)
 176 {
 177 #ifdef CONFIG_8xx
 178         /* MPC8xx needs this.  Maybe one day we can get rid of it. */
 179         i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 180 #endif
 181
 182 #ifdef DEBUG
 183         printf("%s: addr=0x%02x, reg=0x%02x, val=0x%02x\n",
 184                __func__, addr, reg, val);
 185 #endif
 186
 187         i2c_write(addr, reg, 1, &val, 1);
 188 }
 189
 190 /*
 191  * Functions for setting the current I2C bus and its speed
 192  */
 193
 194 /*
 195  * i2c_set_bus_num:
 196  *
 197  *  Change the active I2C bus.  Subsequent read/write calls will
 198  *  go to this one.
 199  *
 200  *      bus - bus index, zero based
 201  *
 202  *      Returns: 0 on success, not 0 on failure
 203  *
 204  */
 205 int i2c_set_bus_num(unsigned int bus);
 206
 207 /*
 208  * i2c_get_bus_num:
 209  *
 210  *  Returns index of currently active I2C bus.  Zero-based.
 211  */
 212
 213 unsigned int i2c_get_bus_num(void);
 214
 215 /*
 216  * i2c_set_bus_speed:
 217  *
 218  *  Change the speed of the active I2C bus
 219  *
 220  *      speed - bus speed in Hz
 221  *
 222  *      Returns: 0 on success, not 0 on failure
 223  *
 224  */
 225 int i2c_set_bus_speed(unsigned int);
 226
 227 /*
 228  * i2c_get_bus_speed:
 229  *
 230  *  Returns speed of currently active I2C bus in Hz
 231  */
 232
 233 unsigned int i2c_get_bus_speed(void);
 234
 235 #endif  /* _I2C_H_ */