i2c/busses/i2c-sibyte.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Copyright (C) 2004 Steven J. Hill
0004  * Copyright (C) 2001,2002,2003 Broadcom Corporation
0005  * Copyright (C) 1995-2000 Simon G. Vogl
0006  */
0007
0008 #include <linux/kernel.h>
0009 #include <linux/module.h>
0010 #include <linux/init.h>
0011 #include <linux/i2c.h>
0012 #include <linux/io.h>
0013 #include <asm/sibyte/sb1250_regs.h>
0014 #include <asm/sibyte/sb1250_smbus.h>
0015
0016
0017 struct i2c_algo_sibyte_data {
0018     void *data;     /* private data */
0019     int   bus;      /* which bus */
0020     void *reg_base;     /* CSR base */
0021 };
0022
0023 /* ----- global defines ----------------------------------------------- */
0024 #define SMB_CSR(a,r) ((long)(a->reg_base + r))
0025
0026
0027 static int smbus_xfer(struct i2c_adapter *i2c_adap, u16 addr,
0028               unsigned short flags, char read_write,
0029               u8 command, int size, union i2c_smbus_data * data)
0030 {
0031     struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
0032     int data_bytes = 0;
0033     int error;
0034
0035     while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
0036         ;
0037
0038     switch (size) {
0039     case I2C_SMBUS_QUICK:
0040         csr_out32((V_SMB_ADDR(addr) |
0041                (read_write == I2C_SMBUS_READ ? M_SMB_QDATA : 0) |
0042                V_SMB_TT_QUICKCMD), SMB_CSR(adap, R_SMB_START));
0043         break;
0044     case I2C_SMBUS_BYTE:
0045         if (read_write == I2C_SMBUS_READ) {
0046             csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_RD1BYTE),
0047                   SMB_CSR(adap, R_SMB_START));
0048             data_bytes = 1;
0049         } else {
0050             csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
0051             csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR1BYTE),
0052                   SMB_CSR(adap, R_SMB_START));
0053         }
0054         break;
0055     case I2C_SMBUS_BYTE_DATA:
0056         csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
0057         if (read_write == I2C_SMBUS_READ) {
0058             csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_CMD_RD1BYTE),
0059                   SMB_CSR(adap, R_SMB_START));
0060             data_bytes = 1;
0061         } else {
0062             csr_out32(V_SMB_LB(data->byte),
0063                   SMB_CSR(adap, R_SMB_DATA));
0064             csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
0065                   SMB_CSR(adap, R_SMB_START));
0066         }
0067         break;
0068     case I2C_SMBUS_WORD_DATA:
0069         csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
0070         if (read_write == I2C_SMBUS_READ) {
0071             csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_CMD_RD2BYTE),
0072                   SMB_CSR(adap, R_SMB_START));
0073             data_bytes = 2;
0074         } else {
0075             csr_out32(V_SMB_LB(data->word & 0xff),
0076                   SMB_CSR(adap, R_SMB_DATA));
0077             csr_out32(V_SMB_MB(data->word >> 8),
0078                   SMB_CSR(adap, R_SMB_DATA));
0079             csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
0080                   SMB_CSR(adap, R_SMB_START));
0081         }
0082         break;
0083     default:
0084         return -EOPNOTSUPP;
0085     }
0086
0087     while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
0088         ;
0089
0090     error = csr_in32(SMB_CSR(adap, R_SMB_STATUS));
0091     if (error & M_SMB_ERROR) {
0092         /* Clear error bit by writing a 1 */
0093         csr_out32(M_SMB_ERROR, SMB_CSR(adap, R_SMB_STATUS));
0094         return (error & M_SMB_ERROR_TYPE) ? -EIO : -ENXIO;
0095     }
0096
0097     if (data_bytes == 1)
0098         data->byte = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xff;
0099     if (data_bytes == 2)
0100         data->word = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xffff;
0101
0102     return 0;
0103 }
0104
0105 static u32 bit_func(struct i2c_adapter *adap)
0106 {
0107     return (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
0108         I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA);
0109 }
0110
0111
0112 /* -----exported algorithm data: -------------------------------------  */
0113
0114 static const struct i2c_algorithm i2c_sibyte_algo = {
0115     .smbus_xfer = smbus_xfer,
0116     .functionality  = bit_func,
0117 };
0118
0119 /*
0120  * registering functions to load algorithms at runtime
0121  */
0122 static int __init i2c_sibyte_add_bus(struct i2c_adapter *i2c_adap, int speed)
0123 {
0124     struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
0125
0126     /* Register new adapter to i2c module... */
0127     i2c_adap->algo = &i2c_sibyte_algo;
0128
0129     /* Set the requested frequency. */
0130     csr_out32(speed, SMB_CSR(adap,R_SMB_FREQ));
0131     csr_out32(0, SMB_CSR(adap,R_SMB_CONTROL));
0132
0133     return i2c_add_numbered_adapter(i2c_adap);
0134 }
0135
0136
0137 static struct i2c_algo_sibyte_data sibyte_board_data[2] = {
0138     { NULL, 0, (void *) (CKSEG1+A_SMB_BASE(0)) },
0139     { NULL, 1, (void *) (CKSEG1+A_SMB_BASE(1)) }
0140 };
0141
0142 static struct i2c_adapter sibyte_board_adapter[2] = {
0143     {
0144         .owner      = THIS_MODULE,
0145         .class      = I2C_CLASS_HWMON | I2C_CLASS_SPD,
0146         .algo       = NULL,
0147         .algo_data  = &sibyte_board_data[0],
0148         .nr     = 0,
0149         .name       = "SiByte SMBus 0",
0150     },
0151     {
0152         .owner      = THIS_MODULE,
0153         .class      = I2C_CLASS_HWMON | I2C_CLASS_SPD,
0154         .algo       = NULL,
0155         .algo_data  = &sibyte_board_data[1],
0156         .nr     = 1,
0157         .name       = "SiByte SMBus 1",
0158     },
0159 };
0160
0161 static int __init i2c_sibyte_init(void)
0162 {
0163     pr_info("i2c-sibyte: i2c SMBus adapter module for SiByte board\n");
0164     if (i2c_sibyte_add_bus(&sibyte_board_adapter[0], K_SMB_FREQ_100KHZ) < 0)
0165         return -ENODEV;
0166     if (i2c_sibyte_add_bus(&sibyte_board_adapter[1],
0167                    K_SMB_FREQ_400KHZ) < 0) {
0168         i2c_del_adapter(&sibyte_board_adapter[0]);
0169         return -ENODEV;
0170     }
0171     return 0;
0172 }
0173
0174 static void __exit i2c_sibyte_exit(void)
0175 {
0176     i2c_del_adapter(&sibyte_board_adapter[0]);
0177     i2c_del_adapter(&sibyte_board_adapter[1]);
0178 }
0179
0180 module_init(i2c_sibyte_init);
0181 module_exit(i2c_sibyte_exit);
0182
0183 MODULE_AUTHOR("Kip Walker (Broadcom Corp.)");
0184 MODULE_AUTHOR("Steven J. Hill <sjhill@realitydiluted.com>");
0185 MODULE_DESCRIPTION("SMBus adapter routines for SiByte boards");
0186 MODULE_LICENSE("GPL");