drivers/i2c/busses/i2c-sibyte.c

   1 /*
   2  * Copyright (C) 2004 Steven J. Hill
   3  * Copyright (C) 2001,2002,2003 Broadcom Corporation
   4  * Copyright (C) 1995-2000 Simon G. Vogl
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  19  */
  20
  21 #include <linux/kernel.h>
  22 #include <linux/module.h>
  23 #include <linux/init.h>
  24 #include <linux/i2c.h>
  25 #include <asm/io.h>
  26 #include <asm/sibyte/sb1250_regs.h>
  27 #include <asm/sibyte/sb1250_smbus.h>
  28
  29
  30 struct i2c_algo_sibyte_data {
  31         void *data;             /* private data */
  32         int   bus;              /* which bus */
  33         void *reg_base;         /* CSR base */
  34 };
  35
  36 /* ----- global defines ----------------------------------------------- */
  37 #define SMB_CSR(a,r) ((long)(a->reg_base + r))
  38
  39 /* ----- global variables --------------------------------------------- */
  40
  41 /* module parameters:
  42  */
  43 static int bit_scan;    /* have a look at what's hanging 'round */
  44 module_param(bit_scan, int, 0);
  45 MODULE_PARM_DESC(bit_scan, "Scan for active chips on the bus");
  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) |
  62                            (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),
  84                                   SMB_CSR(adap, R_SMB_DATA));
  85                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
  86                                   SMB_CSR(adap, R_SMB_START));
  87                 }
  88                 break;
  89         case I2C_SMBUS_WORD_DATA:
  90                 csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  91                 if (read_write == I2C_SMBUS_READ) {
  92                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_CMD_RD2BYTE),
  93                                   SMB_CSR(adap, R_SMB_START));
  94                         data_bytes = 2;
  95                 } else {
  96                         csr_out32(V_SMB_LB(data->word & 0xff),
  97                                   SMB_CSR(adap, R_SMB_DATA));
  98                         csr_out32(V_SMB_MB(data->word >> 8),
  99                                   SMB_CSR(adap, R_SMB_DATA));
 100                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
 101                                   SMB_CSR(adap, R_SMB_START));
 102                 }
 103                 break;
 104         default:
 105                 return -1;      /* XXXKW better error code? */
 106         }
 107
 108         while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
 109                 ;
 110
 111         error = csr_in32(SMB_CSR(adap, R_SMB_STATUS));
 112         if (error & M_SMB_ERROR) {
 113                 /* Clear error bit by writing a 1 */
 114                 csr_out32(M_SMB_ERROR, SMB_CSR(adap, R_SMB_STATUS));
 115                 return -1;      /* XXXKW better error code? */
 116         }
 117
 118         if (data_bytes == 1)
 119                 data->byte = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xff;
 120         if (data_bytes == 2)
 121                 data->word = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xffff;
 122
 123         return 0;
 124 }
 125
 126 static u32 bit_func(struct i2c_adapter *adap)
 127 {
 128         return (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 129                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA);
 130 }
 131
 132
 133 /* -----exported algorithm data: -------------------------------------  */
 134
 135 static const struct i2c_algorithm i2c_sibyte_algo = {
 136         .smbus_xfer     = smbus_xfer,
 137         .functionality  = bit_func,
 138 };
 139
 140 /*
 141  * registering functions to load algorithms at runtime
 142  */
 143 int i2c_sibyte_add_bus(struct i2c_adapter *i2c_adap, int speed)
 144 {
 145         int i;
 146         struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
 147
 148         /* register new adapter to i2c module... */
 149         i2c_adap->algo = &i2c_sibyte_algo;
 150
 151         /* Set the frequency to 100 kHz */
 152         csr_out32(speed, SMB_CSR(adap,R_SMB_FREQ));
 153         csr_out32(0, SMB_CSR(adap,R_SMB_CONTROL));
 154
 155         /* scan bus */
 156         if (bit_scan) {
 157                 union i2c_smbus_data data;
 158                 int rc;
 159                 printk(KERN_INFO " i2c-algo-sibyte.o: scanning bus %s.\n",
 160                        i2c_adap->name);
 161                 for (i = 0x00; i < 0x7f; i++) {
 162                         /* XXXKW is this a realistic probe? */
 163                         rc = smbus_xfer(i2c_adap, i, 0, I2C_SMBUS_READ, 0,
 164                                         I2C_SMBUS_BYTE_DATA, &data);
 165                         if (!rc) {
 166                                 printk("(%02x)",i);
 167                         } else
 168                                 printk(".");
 169                 }
 170                 printk("\n");
 171         }
 172
 173         return i2c_add_adapter(i2c_adap);
 174 }
 175
 176
 177 static struct i2c_algo_sibyte_data sibyte_board_data[2] = {
 178         { NULL, 0, (void *) (CKSEG1+A_SMB_BASE(0)) },
 179         { NULL, 1, (void *) (CKSEG1+A_SMB_BASE(1)) }
 180 };
 181
 182 static struct i2c_adapter sibyte_board_adapter[2] = {
 183         {
 184                 .owner          = THIS_MODULE,
 185                 .id             = I2C_HW_SIBYTE,
 186                 .class          = I2C_CLASS_HWMON,
 187                 .algo           = NULL,
 188                 .algo_data      = &sibyte_board_data[0],
 189                 .name           = "SiByte SMBus 0",
 190         },
 191         {
 192                 .owner          = THIS_MODULE,
 193                 .id             = I2C_HW_SIBYTE,
 194                 .class          = I2C_CLASS_HWMON,
 195                 .algo           = NULL,
 196                 .algo_data      = &sibyte_board_data[1],
 197                 .name           = "SiByte SMBus 1",
 198         },
 199 };
 200
 201 static int __init i2c_sibyte_init(void)
 202 {
 203         printk("i2c-swarm.o: i2c SMBus adapter module for SiByte board\n");
 204         if (i2c_sibyte_add_bus(&sibyte_board_adapter[0], K_SMB_FREQ_100KHZ) < 0)
 205                 return -ENODEV;
 206         if (i2c_sibyte_add_bus(&sibyte_board_adapter[1], K_SMB_FREQ_400KHZ) < 0)
 207                 return -ENODEV;
 208         return 0;
 209 }
 210
 211 static void __exit i2c_sibyte_exit(void)
 212 {
 213         i2c_del_adapter(&sibyte_board_adapter[0]);
 214         i2c_del_adapter(&sibyte_board_adapter[1]);
 215 }
 216
 217 module_init(i2c_sibyte_init);
 218 module_exit(i2c_sibyte_exit);
 219
 220 MODULE_AUTHOR("Kip Walker (Broadcom Corp.), Steven J. Hill <sjhill@realitydiluted.com>");
 221 MODULE_DESCRIPTION("SMBus adapter routines for SiByte boards");
 222 MODULE_LICENSE("GPL");