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/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/init.h>
  30
  31 #include <asm/io.h>
  32 #include <asm/sibyte/sb1250_regs.h>
  33 #include <asm/sibyte/sb1250_smbus.h>
  34
  35 #include <linux/i2c.h>
  36 #include <linux/i2c-algo-sibyte.h>
  37
  38 /* ----- global defines ----------------------------------------------- */
  39 #define SMB_CSR(a,r) ((long)(a->reg_base + r))
  40
  41 /* ----- global variables --------------------------------------------- */
  42
  43 /* module parameters:
  44  */
  45 static int bit_scan;    /* have a look at what's hanging 'round         */
  46
  47
  48 static int smbus_xfer(struct i2c_adapter *i2c_adap, u16 addr,
  49                       unsigned short flags, char read_write,
  50                       u8 command, int size, union i2c_smbus_data * data)
  51 {
  52         struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
  53         int data_bytes = 0;
  54         int error;
  55
  56         while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
  57                 ;
  58
  59         switch (size) {
  60         case I2C_SMBUS_QUICK:
  61                 csr_out32((V_SMB_ADDR(addr) | (read_write == I2C_SMBUS_READ ? M_SMB_QDATA : 0) |
  62                            V_SMB_TT_QUICKCMD), SMB_CSR(adap, R_SMB_START));
  63                 break;
  64         case I2C_SMBUS_BYTE:
  65                 if (read_write == I2C_SMBUS_READ) {
  66                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_RD1BYTE),
  67                                   SMB_CSR(adap, R_SMB_START));
  68                         data_bytes = 1;
  69                 } else {
  70                         csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  71                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR1BYTE),
  72                                   SMB_CSR(adap, R_SMB_START));
  73                 }
  74                 break;
  75         case I2C_SMBUS_BYTE_DATA:
  76                 csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  77                 if (read_write == I2C_SMBUS_READ) {
  78                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_CMD_RD1BYTE),
  79                                   SMB_CSR(adap, R_SMB_START));
  80                         data_bytes = 1;
  81                 } else {
  82                         csr_out32(V_SMB_LB(data->byte), SMB_CSR(adap, R_SMB_DATA));
  83                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
  84                                   SMB_CSR(adap, R_SMB_START));
  85                 }
  86                 break;
  87         case I2C_SMBUS_WORD_DATA:
  88                 csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  89                 if (read_write == I2C_SMBUS_READ) {
  90                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_CMD_RD2BYTE),
  91                                   SMB_CSR(adap, R_SMB_START));
  92                         data_bytes = 2;
  93                 } else {
  94                         csr_out32(V_SMB_LB(data->word & 0xff), SMB_CSR(adap, R_SMB_DATA));
  95                         csr_out32(V_SMB_MB(data->word >> 8), SMB_CSR(adap, R_SMB_DATA));
  96                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
  97                                   SMB_CSR(adap, R_SMB_START));
  98                 }
  99                 break;
 100         default:
 101                 return -1;      /* XXXKW better error code? */
 102         }
 103
 104         while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
 105                 ;
 106
 107         error = csr_in32(SMB_CSR(adap, R_SMB_STATUS));
 108         if (error & M_SMB_ERROR) {
 109                 /* Clear error bit by writing a 1 */
 110                 csr_out32(M_SMB_ERROR, SMB_CSR(adap, R_SMB_STATUS));
 111                 return -1;      /* XXXKW better error code? */
 112         }
 113
 114         if (data_bytes == 1)
 115                 data->byte = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xff;
 116         if (data_bytes == 2)
 117                 data->word = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xffff;
 118
 119         return 0;
 120 }
 121
 122 static u32 bit_func(struct i2c_adapter *adap)
 123 {
 124         return (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 125                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA);
 126 }
 127
 128
 129 /* -----exported algorithm data: -------------------------------------  */
 130
 131 static struct i2c_algorithm i2c_sibyte_algo = {
 132         .smbus_xfer     = smbus_xfer,
 133         .functionality  = bit_func,
 134 };
 135
 136 /*
 137  * registering functions to load algorithms at runtime
 138  */
 139 int i2c_sibyte_add_bus(struct i2c_adapter *i2c_adap, int speed)
 140 {
 141         int i;
 142         struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
 143
 144         /* register new adapter to i2c module... */
 145         i2c_adap->algo = &i2c_sibyte_algo;
 146
 147         /* Set the frequency to 100 kHz */
 148         csr_out32(speed, SMB_CSR(adap,R_SMB_FREQ));
 149         csr_out32(0, SMB_CSR(adap,R_SMB_CONTROL));
 150
 151         /* scan bus */
 152         if (bit_scan) {
 153                 union i2c_smbus_data data;
 154                 int rc;
 155                 printk(KERN_INFO " i2c-algo-sibyte.o: scanning bus %s.\n",
 156                        i2c_adap->name);
 157                 for (i = 0x00; i < 0x7f; i++) {
 158                         /* XXXKW is this a realistic probe? */
 159                         rc = smbus_xfer(i2c_adap, i, 0, I2C_SMBUS_READ, 0,
 160                                         I2C_SMBUS_BYTE_DATA, &data);
 161                         if (!rc) {
 162                                 printk("(%02x)",i);
 163                         } else
 164                                 printk(".");
 165                 }
 166                 printk("\n");
 167         }
 168
 169         return i2c_add_adapter(i2c_adap);
 170 }
 171
 172
 173 int i2c_sibyte_del_bus(struct i2c_adapter *adap)
 174 {
 175         return i2c_del_adapter(adap);
 176 }
 177
 178
 179 EXPORT_SYMBOL(i2c_sibyte_add_bus);
 180 EXPORT_SYMBOL(i2c_sibyte_del_bus);
 181
 182 MODULE_AUTHOR("Kip Walker, Broadcom Corp.");
 183 MODULE_DESCRIPTION("SiByte I2C-Bus algorithm");
 184 module_param(bit_scan, int, 0);
 185 MODULE_PARM_DESC(bit_scan, "Scan for active chips on the bus");
 186 MODULE_LICENSE("GPL");