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
  40 static int smbus_xfer(struct i2c_adapter *i2c_adap, u16 addr,
  41                       unsigned short flags, char read_write,
  42                       u8 command, int size, union i2c_smbus_data * data)
  43 {
  44         struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
  45         int data_bytes = 0;
  46         int error;
  47
  48         while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
  49                 ;
  50
  51         switch (size) {
  52         case I2C_SMBUS_QUICK:
  53                 csr_out32((V_SMB_ADDR(addr) |
  54                            (read_write == I2C_SMBUS_READ ? M_SMB_QDATA : 0) |
  55                            V_SMB_TT_QUICKCMD), SMB_CSR(adap, R_SMB_START));
  56                 break;
  57         case I2C_SMBUS_BYTE:
  58                 if (read_write == I2C_SMBUS_READ) {
  59                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_RD1BYTE),
  60                                   SMB_CSR(adap, R_SMB_START));
  61                         data_bytes = 1;
  62                 } else {
  63                         csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  64                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR1BYTE),
  65                                   SMB_CSR(adap, R_SMB_START));
  66                 }
  67                 break;
  68         case I2C_SMBUS_BYTE_DATA:
  69                 csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  70                 if (read_write == I2C_SMBUS_READ) {
  71                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_CMD_RD1BYTE),
  72                                   SMB_CSR(adap, R_SMB_START));
  73                         data_bytes = 1;
  74                 } else {
  75                         csr_out32(V_SMB_LB(data->byte),
  76                                   SMB_CSR(adap, R_SMB_DATA));
  77                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
  78                                   SMB_CSR(adap, R_SMB_START));
  79                 }
  80                 break;
  81         case I2C_SMBUS_WORD_DATA:
  82                 csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
  83                 if (read_write == I2C_SMBUS_READ) {
  84                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_CMD_RD2BYTE),
  85                                   SMB_CSR(adap, R_SMB_START));
  86                         data_bytes = 2;
  87                 } else {
  88                         csr_out32(V_SMB_LB(data->word & 0xff),
  89                                   SMB_CSR(adap, R_SMB_DATA));
  90                         csr_out32(V_SMB_MB(data->word >> 8),
  91                                   SMB_CSR(adap, R_SMB_DATA));
  92                         csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
  93                                   SMB_CSR(adap, R_SMB_START));
  94                 }
  95                 break;
  96         default:
  97                 return -1;      /* XXXKW better error code? */
  98         }
  99
 100         while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
 101                 ;
 102
 103         error = csr_in32(SMB_CSR(adap, R_SMB_STATUS));
 104         if (error & M_SMB_ERROR) {
 105                 /* Clear error bit by writing a 1 */
 106                 csr_out32(M_SMB_ERROR, SMB_CSR(adap, R_SMB_STATUS));
 107                 return -1;      /* XXXKW better error code? */
 108         }
 109
 110         if (data_bytes == 1)
 111                 data->byte = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xff;
 112         if (data_bytes == 2)
 113                 data->word = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xffff;
 114
 115         return 0;
 116 }
 117
 118 static u32 bit_func(struct i2c_adapter *adap)
 119 {
 120         return (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 121                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA);
 122 }
 123
 124
 125 /* -----exported algorithm data: -------------------------------------  */
 126
 127 static const struct i2c_algorithm i2c_sibyte_algo = {
 128         .smbus_xfer     = smbus_xfer,
 129         .functionality  = bit_func,
 130 };
 131
 132 /*
 133  * registering functions to load algorithms at runtime
 134  */
 135 static int __init i2c_sibyte_add_bus(struct i2c_adapter *i2c_adap, int speed)
 136 {
 137         struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
 138
 139         /* Register new adapter to i2c module... */
 140         i2c_adap->algo = &i2c_sibyte_algo;
 141
 142         /* Set the requested frequency. */
 143         csr_out32(speed, SMB_CSR(adap,R_SMB_FREQ));
 144         csr_out32(0, SMB_CSR(adap,R_SMB_CONTROL));
 145
 146         return i2c_add_adapter(i2c_adap);
 147 }
 148
 149
 150 static struct i2c_algo_sibyte_data sibyte_board_data[2] = {
 151         { NULL, 0, (void *) (CKSEG1+A_SMB_BASE(0)) },
 152         { NULL, 1, (void *) (CKSEG1+A_SMB_BASE(1)) }
 153 };
 154
 155 static struct i2c_adapter sibyte_board_adapter[2] = {
 156         {
 157                 .owner          = THIS_MODULE,
 158                 .id             = I2C_HW_SIBYTE,
 159                 .class          = I2C_CLASS_HWMON,
 160                 .algo           = NULL,
 161                 .algo_data      = &sibyte_board_data[0],
 162                 .name           = "SiByte SMBus 0",
 163         },
 164         {
 165                 .owner          = THIS_MODULE,
 166                 .id             = I2C_HW_SIBYTE,
 167                 .class          = I2C_CLASS_HWMON,
 168                 .algo           = NULL,
 169                 .algo_data      = &sibyte_board_data[1],
 170                 .name           = "SiByte SMBus 1",
 171         },
 172 };
 173
 174 static int __init i2c_sibyte_init(void)
 175 {
 176         pr_info("i2c-sibyte: i2c SMBus adapter module for SiByte board\n");
 177         if (i2c_sibyte_add_bus(&sibyte_board_adapter[0], K_SMB_FREQ_100KHZ) < 0)
 178                 return -ENODEV;
 179         if (i2c_sibyte_add_bus(&sibyte_board_adapter[1],
 180                                K_SMB_FREQ_400KHZ) < 0) {
 181                 i2c_del_adapter(&sibyte_board_adapter[0]);
 182                 return -ENODEV;
 183         }
 184         return 0;
 185 }
 186
 187 static void __exit i2c_sibyte_exit(void)
 188 {
 189         i2c_del_adapter(&sibyte_board_adapter[0]);
 190         i2c_del_adapter(&sibyte_board_adapter[1]);
 191 }
 192
 193 module_init(i2c_sibyte_init);
 194 module_exit(i2c_sibyte_exit);
 195
 196 MODULE_AUTHOR("Kip Walker (Broadcom Corp.), Steven J. Hill <sjhill@realitydiluted.com>");
 197 MODULE_DESCRIPTION("SMBus adapter routines for SiByte boards");
 198 MODULE_LICENSE("GPL");