xref: /openbmc/linux/drivers/i2c/busses/i2c-sibyte.c (revision f80531c8)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2004 Steven J. Hill
4  * Copyright (C) 2001,2002,2003 Broadcom Corporation
5  * Copyright (C) 1995-2000 Simon G. Vogl
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/i2c.h>
12 #include <linux/io.h>
13 #include <asm/sibyte/sb1250_regs.h>
14 #include <asm/sibyte/sb1250_smbus.h>
15 
16 
17 struct i2c_algo_sibyte_data {
18 	void *data;		/* private data */
19 	int   bus;		/* which bus */
20 	void *reg_base;		/* CSR base */
21 };
22 
23 /* ----- global defines ----------------------------------------------- */
24 #define SMB_CSR(a,r) ((long)(a->reg_base + r))
25 
26 
smbus_xfer(struct i2c_adapter * i2c_adap,u16 addr,unsigned short flags,char read_write,u8 command,int size,union i2c_smbus_data * data)27 static int smbus_xfer(struct i2c_adapter *i2c_adap, u16 addr,
28 		      unsigned short flags, char read_write,
29 		      u8 command, int size, union i2c_smbus_data * data)
30 {
31 	struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
32 	int data_bytes = 0;
33 	int error;
34 
35 	while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
36 		;
37 
38 	switch (size) {
39 	case I2C_SMBUS_QUICK:
40 		csr_out32((V_SMB_ADDR(addr) |
41 			   (read_write == I2C_SMBUS_READ ? M_SMB_QDATA : 0) |
42 			   V_SMB_TT_QUICKCMD), SMB_CSR(adap, R_SMB_START));
43 		break;
44 	case I2C_SMBUS_BYTE:
45 		if (read_write == I2C_SMBUS_READ) {
46 			csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_RD1BYTE),
47 				  SMB_CSR(adap, R_SMB_START));
48 			data_bytes = 1;
49 		} else {
50 			csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
51 			csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR1BYTE),
52 				  SMB_CSR(adap, R_SMB_START));
53 		}
54 		break;
55 	case I2C_SMBUS_BYTE_DATA:
56 		csr_out32(V_SMB_CMD(command), SMB_CSR(adap, R_SMB_CMD));
57 		if (read_write == I2C_SMBUS_READ) {
58 			csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_CMD_RD1BYTE),
59 				  SMB_CSR(adap, R_SMB_START));
60 			data_bytes = 1;
61 		} else {
62 			csr_out32(V_SMB_LB(data->byte),
63 				  SMB_CSR(adap, R_SMB_DATA));
64 			csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
65 				  SMB_CSR(adap, R_SMB_START));
66 		}
67 		break;
68 	case I2C_SMBUS_WORD_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_RD2BYTE),
72 				  SMB_CSR(adap, R_SMB_START));
73 			data_bytes = 2;
74 		} else {
75 			csr_out32(V_SMB_LB(data->word & 0xff),
76 				  SMB_CSR(adap, R_SMB_DATA));
77 			csr_out32(V_SMB_MB(data->word >> 8),
78 				  SMB_CSR(adap, R_SMB_DATA));
79 			csr_out32((V_SMB_ADDR(addr) | V_SMB_TT_WR2BYTE),
80 				  SMB_CSR(adap, R_SMB_START));
81 		}
82 		break;
83 	default:
84 		return -EOPNOTSUPP;
85 	}
86 
87 	while (csr_in32(SMB_CSR(adap, R_SMB_STATUS)) & M_SMB_BUSY)
88 		;
89 
90 	error = csr_in32(SMB_CSR(adap, R_SMB_STATUS));
91 	if (error & M_SMB_ERROR) {
92 		/* Clear error bit by writing a 1 */
93 		csr_out32(M_SMB_ERROR, SMB_CSR(adap, R_SMB_STATUS));
94 		return (error & M_SMB_ERROR_TYPE) ? -EIO : -ENXIO;
95 	}
96 
97 	if (data_bytes == 1)
98 		data->byte = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xff;
99 	if (data_bytes == 2)
100 		data->word = csr_in32(SMB_CSR(adap, R_SMB_DATA)) & 0xffff;
101 
102 	return 0;
103 }
104 
bit_func(struct i2c_adapter * adap)105 static u32 bit_func(struct i2c_adapter *adap)
106 {
107 	return (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
108 		I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA);
109 }
110 
111 
112 /* -----exported algorithm data: -------------------------------------	*/
113 
114 static const struct i2c_algorithm i2c_sibyte_algo = {
115 	.smbus_xfer	= smbus_xfer,
116 	.functionality	= bit_func,
117 };
118 
119 /*
120  * registering functions to load algorithms at runtime
121  */
i2c_sibyte_add_bus(struct i2c_adapter * i2c_adap,int speed)122 static int __init i2c_sibyte_add_bus(struct i2c_adapter *i2c_adap, int speed)
123 {
124 	struct i2c_algo_sibyte_data *adap = i2c_adap->algo_data;
125 
126 	/* Register new adapter to i2c module... */
127 	i2c_adap->algo = &i2c_sibyte_algo;
128 
129 	/* Set the requested frequency. */
130 	csr_out32(speed, SMB_CSR(adap,R_SMB_FREQ));
131 	csr_out32(0, SMB_CSR(adap,R_SMB_CONTROL));
132 
133 	return i2c_add_numbered_adapter(i2c_adap);
134 }
135 
136 
137 static struct i2c_algo_sibyte_data sibyte_board_data[2] = {
138 	{ NULL, 0, (void *) (CKSEG1+A_SMB_BASE(0)) },
139 	{ NULL, 1, (void *) (CKSEG1+A_SMB_BASE(1)) }
140 };
141 
142 static struct i2c_adapter sibyte_board_adapter[2] = {
143 	{
144 		.owner		= THIS_MODULE,
145 		.class		= I2C_CLASS_HWMON | I2C_CLASS_SPD,
146 		.algo		= NULL,
147 		.algo_data	= &sibyte_board_data[0],
148 		.nr		= 0,
149 		.name		= "SiByte SMBus 0",
150 	},
151 	{
152 		.owner		= THIS_MODULE,
153 		.class		= I2C_CLASS_HWMON | I2C_CLASS_SPD,
154 		.algo		= NULL,
155 		.algo_data	= &sibyte_board_data[1],
156 		.nr		= 1,
157 		.name		= "SiByte SMBus 1",
158 	},
159 };
160 
i2c_sibyte_init(void)161 static int __init i2c_sibyte_init(void)
162 {
163 	pr_info("i2c-sibyte: i2c SMBus adapter module for SiByte board\n");
164 	if (i2c_sibyte_add_bus(&sibyte_board_adapter[0], K_SMB_FREQ_100KHZ) < 0)
165 		return -ENODEV;
166 	if (i2c_sibyte_add_bus(&sibyte_board_adapter[1],
167 			       K_SMB_FREQ_400KHZ) < 0) {
168 		i2c_del_adapter(&sibyte_board_adapter[0]);
169 		return -ENODEV;
170 	}
171 	return 0;
172 }
173 
i2c_sibyte_exit(void)174 static void __exit i2c_sibyte_exit(void)
175 {
176 	i2c_del_adapter(&sibyte_board_adapter[0]);
177 	i2c_del_adapter(&sibyte_board_adapter[1]);
178 }
179 
180 module_init(i2c_sibyte_init);
181 module_exit(i2c_sibyte_exit);
182 
183 MODULE_AUTHOR("Kip Walker (Broadcom Corp.)");
184 MODULE_AUTHOR("Steven J. Hill <sjhill@realitydiluted.com>");
185 MODULE_DESCRIPTION("SMBus adapter routines for SiByte boards");
186 MODULE_LICENSE("GPL");
187