drivers/i2c/algos/i2c-algo-sibyte.c

   1 /* ------------------------------------------------------------------------- */
   2 /* i2c-algo-sibyte.c i2c driver algorithms for bit-shift adapters                    */
   3 /* ------------------------------------------------------------------------- */
   4 /*   Copyright (C) 2001,2002,2003 Broadcom Corporation
   5      Copyright (C) 1995-2000 Simon G. Vogl
   6
   7     This program is free software; you can redistribute it and/or modify
   8     it under the terms of the GNU General Public License as published by
   9     the Free Software Foundation; either version 2 of the License, or
  10     (at your option) any later version.
  11
  12     This program is distributed in the hope that it will be useful,
  13     but WITHOUT ANY WARRANTY; without even the implied warranty of
  14     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15     GNU General Public License for more details.
  16
  17     You should have received a copy of the GNU General Public License
  18     along with this program; if not, write to the Free Software
  19     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.                */
  20 /* ------------------------------------------------------------------------- */
  21
  22 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> and even
  23    Frodo Looijaard <frodol@dds.nl>.  */
  24
  25 /* Ported for SiByte SOCs by Broadcom Corporation.  */
  26
  27 #include <linux/config.h>
  28 #include <linux/kernel.h>
  29 #include <linux/module.h>
  30 #include <linux/init.h>
  31
  32 #include <asm/io.h>
  33 #include <asm/sibyte/sb1250_regs.h>
  34 #include <asm/sibyte/sb1250_smbus.h>
  35
  36 #include <linux/i2c.h>
  37 #include <linux/i2c-algo-sibyte.h>
  38
  39 /* ----- global defines ----------------------------------------------- */
  40 #define SMB_CSR(a,r) ((long)(a->reg_base + r))
  41
  42 /* ----- global variables --------------------------------------------- */
  43
  44 /* module parameters:
  45  */
  46 static int bit_scan=0;  /* have a look at what's hanging 'round         */
  47
  48
  49 static int smbus_xfer(struct i2c_adapter *i2c_adap, u16 addr,
  50                       unsigned short flags, char read_write,
  51                       u8 command, int size, union i2c_smbus_data * data)
  52 {
  53         struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
  54         int data_bytes = 0;
  55         int error;
  56
  57         while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
  58                 ;
  59
  60         switch (size) {
  61         case I2C_SMBUS_QUICK:
  62                 csr_out32((V_SMB_ADDR(addr) | (read_write == I2C_SMBUS_READ ? M_SMB_QDATA : 0) |
  63                            V_SMB_TT_QUICKCMD), SMB_CSR(adap, R_SMB_START));
  64                 break;
  65         case I2C_SMBUS_BYTE:
  66                 if (read_write == I2C_SMBUS_READ) {
  67                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_RD1BYTE),
  68                                   SMB_CSR(adap, R_SMB_START));
  69                         data_bytes = 1;
  70                 } else {
  71                         csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  72                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR1BYTE),
  73                                   SMB_CSR(adap, R_SMB_START));
  74                 }
  75                 break;
  76         case I2C_SMBUS_BYTE_DATA:
  77                 csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  78                 if (read_write == I2C_SMBUS_READ) {
  79                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_CMD_RD1BYTE),
  80                                   SMB_CSR(adap, R_SMB_START));
  81                         data_bytes = 1;
  82                 } else {
  83                         csr_out32(V_SMB_LB(data->byte), SMB_CSR(adap, R_SMB_DATA));
  84                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
  85                                   SMB_CSR(adap, R_SMB_START));
  86                 }
  87                 break;
  88         case I2C_SMBUS_WORD_DATA:
  89                 csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  90                 if (read_write == I2C_SMBUS_READ) {
  91                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_CMD_RD2BYTE),
  92                                   SMB_CSR(adap, R_SMB_START));
  93                         data_bytes = 2;
  94                 } else {
  95                         csr_out32(V_SMB_LB(data->word & 0xff), SMB_CSR(adap, R_SMB_DATA));
  96                         csr_out32(V_SMB_MB(data->word >> 8), SMB_CSR(adap, R_SMB_DATA));
  97                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
  98                                   SMB_CSR(adap, R_SMB_START));
  99                 }
 100                 break;
 101         default:
 102                 return -1;      /* XXXKW better error code? */
 103         }
 104
 105         while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
 106                 ;
 107
 108         error = csr_in32(SMB_CSR(adap, R_SMB_STATUS));
 109         if (error & M_SMB_ERROR) {
 110                 /* Clear error bit by writing a 1 */
 111                 csr_out32(M_SMB_ERROR, SMB_CSR(adap, R_SMB_STATUS));
 112                 return -1;      /* XXXKW better error code? */
 113         }
 114
 115         if (data_bytes == 1)
 116                 data->byte = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xff;
 117         if (data_bytes == 2)
 118                 data->word = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xffff;
 119
 120         return 0;
 121 }
 122
 123 static int algo_control(struct i2c_adapter *adapter,
 124         unsigned int cmd, unsigned long arg)
 125 {
 126         return 0;
 127 }
 128
 129 static u32 bit_func(struct i2c_adapter *adap)
 130 {
 131         return (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 132                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA);
 133 }
 134
 135
 136 /* -----exported algorithm data: -------------------------------------  */
 137
 138 static struct i2c_algorithm i2c_sibyte_algo = {
 139         .name           = "SiByte algorithm",
 140         .id             = I2C_ALGO_SIBYTE,
 141         .smbus_xfer     = smbus_xfer,
 142         .algo_control   = algo_control, /* ioctl */
 143         .functionality  = bit_func,
 144 };
 145
 146 /*
 147  * registering functions to load algorithms at runtime
 148  */
 149 int i2c_sibyte_add_bus(struct i2c_adapter *i2c_adap, int speed)
 150 {
 151         int i;
 152         struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
 153
 154         /* register new adapter to i2c module... */
 155
 156         i2c_adap->id |= i2c_sibyte_algo.id;
 157         i2c_adap->algo = &i2c_sibyte_algo;
 158
 159         /* Set the frequency to 100 kHz */
 160         csr_out32(speed, SMB_CSR(adap,R_SMB_FREQ));
 161         csr_out32(0, SMB_CSR(adap,R_SMB_CONTROL));
 162
 163         /* scan bus */
 164         if (bit_scan) {
 165                 union i2c_smbus_data data;
 166                 int rc;
 167                 printk(KERN_INFO " i2c-algo-sibyte.o: scanning bus %s.\n",
 168                        i2c_adap->name);
 169                 for (i = 0x00; i < 0x7f; i++) {
 170                         /* XXXKW is this a realistic probe? */
 171                         rc = smbus_xfer(i2c_adap, i, 0, I2C_SMBUS_READ, 0,
 172                                         I2C_SMBUS_BYTE_DATA, &data);
 173                         if (!rc) {
 174                                 printk("(%02x)",i);
 175                         } else
 176                                 printk(".");
 177                 }
 178                 printk("\n");
 179         }
 180
 181         i2c_add_adapter(i2c_adap);
 182
 183         return 0;
 184 }
 185
 186
 187 int i2c_sibyte_del_bus(struct i2c_adapter *adap)
 188 {
 189         int res;
 190
 191         if ((res = i2c_del_adapter(adap)) < 0)
 192                 return res;
 193
 194         return 0;
 195 }
 196
 197 int __init i2c_algo_sibyte_init (void)
 198 {
 199         printk("i2c-algo-sibyte.o: i2c SiByte algorithm module\n");
 200         return 0;
 201 }
 202
 203
 204 EXPORT_SYMBOL(i2c_sibyte_add_bus);
 205 EXPORT_SYMBOL(i2c_sibyte_del_bus);
 206
 207 #ifdef MODULE
 208 MODULE_AUTHOR("Kip Walker, Broadcom Corp.");
 209 MODULE_DESCRIPTION("SiByte I2C-Bus algorithm");
 210 MODULE_PARM(bit_scan, "i");
 211 MODULE_PARM_DESC(bit_scan, "Scan for active chips on the bus");
 212 MODULE_LICENSE("GPL");
 213
 214 int init_module(void)
 215 {
 216         return i2c_algo_sibyte_init();
 217 }
 218
 219 void cleanup_module(void)
 220 {
 221 }
 222 #endif