1 //#include <device/smbus_def.h>
3 #define SMBUS_WAIT_UNTIL_READY_TIMEOUT -2
4 #define SMBUS_WAIT_UNTIL_DONE_TIMEOUT -3
8 #define SMB_CTRL_STS 0x02
11 #define SMB_CTRL2 0x05
12 #define SMB_CTRL3 0x06
14 #define SMB_STS_SLVSTP (0x01 << 7)
15 #define SMB_STS_SDAST (0x01 << 6)
16 #define SMB_STS_BER (0x01 << 5)
17 #define SMB_STS_NEGACK (0x01 << 4)
18 #define SMB_STS_STASTR (0x01 << 3)
19 #define SMB_STS_NMATCH (0x01 << 2)
20 #define SMB_STS_MASTER (0x01 << 1)
21 #define SMB_STS_XMIT (0x01 << 0)
23 #define SMB_CSTS_TGSCL (0x01 << 5)
24 #define SMB_CSTS_TSDA (0x01 << 4)
25 #define SMB_CSTS_GCMTCH (0x01 << 3)
26 #define SMB_CSTS_MATCH (0x01 << 2)
27 #define SMB_CSTS_BB (0x01 << 1)
28 #define SMB_CSTS_BUSY (0x01 << 0)
30 #define SMB_CTRL1_STASTRE (0x01 << 7)
31 #define SMB_CTRL1_NMINTE (0x01 << 6)
32 #define SMB_CTRL1_GCMEN (0x01 << 5)
33 #define SMB_CTRL1_ACK (0x01 << 4)
34 #define SMB_CTRL1_RSVD (0x01 << 3)
35 #define SMB_CTRL1_INTEN (0x01 << 2)
36 #define SMB_CTRL1_STOP (0x01 << 1)
37 #define SMB_CTRL1_START (0x01 << 0)
39 #define SMB_ADD_SAEN (0x01 << 7)
41 #define SMB_CTRL2_ENABLE 0x01
43 #define SMBUS_TIMEOUT (100*1000*10)
44 #define SMBUS_STATUS_MASK 0xfbff
46 #define SMBUS_IO_BASE 0x6000
48 static void smbus_delay(void)
53 /* generate a smbus start condition */
54 static int smbus_start_condition(unsigned smbus_io_base)
58 loops = SMBUS_TIMEOUT;
60 /* issue a START condition */
61 val = inb(smbus_io_base + SMB_CTRL1);
62 outb(val | SMB_CTRL1_START, smbus_io_base + SMB_CTRL1);
64 /* check for bus conflict */
65 val = inb(smbus_io_base + SMB_STS);
66 if ((val & SMB_STS_BER) != 0)
69 /* check for SDA status */
72 val = inw(smbus_io_base + SMB_STS);
73 if ((val & SMB_STS_SDAST) != 0) {
77 return loops?0:SMBUS_WAIT_UNTIL_READY_TIMEOUT;
80 static int smbus_check_stop_condition(unsigned smbus_io_base)
84 loops = SMBUS_TIMEOUT;
85 /* check for SDA status */
88 val = inw(smbus_io_base + SMB_CTRL1);
89 if ((val & SMB_CTRL1_STOP) == 0) {
93 return loops?0:SMBUS_WAIT_UNTIL_READY_TIMEOUT;
96 static int smbus_stop_condition(unsigned smbus_io_base)
99 val = inb(smbus_io_base + SMB_CTRL1);
100 outb(SMB_CTRL1_STOP, smbus_io_base + SMB_CTRL1);
103 static int smbus_send_slave_address(unsigned smbus_io_base, unsigned char device)
107 loops = SMBUS_TIMEOUT;
109 /* send the slave address */
110 outb(device, smbus_io_base + SMB_SDA);
112 /* check for bus conflict and NACK */
113 val = inb(smbus_io_base + SMB_STS);
114 if (((val & SMB_STS_BER) != 0) ||
115 ((val & SMB_STS_NEGACK) != 0))
118 /* check for SDA status */
121 val = inw(smbus_io_base + SMB_STS);
122 if ((val & SMB_STS_SDAST) != 0) {
126 return loops?0:SMBUS_WAIT_UNTIL_READY_TIMEOUT;
129 static int smbus_send_command(unsigned smbus_io_base, unsigned char command)
133 loops = SMBUS_TIMEOUT;
135 /* send the command */
136 outb(command, smbus_io_base + SMB_SDA);
138 /* check for bus conflict and NACK */
139 val = inb(smbus_io_base + SMB_STS);
140 if (((val & SMB_STS_BER) != 0) ||
141 ((val & SMB_STS_NEGACK) != 0))
144 /* check for SDA status */
147 val = inw(smbus_io_base + SMB_STS);
148 if ((val & SMB_STS_SDAST) != 0) {
152 return loops?0:SMBUS_WAIT_UNTIL_READY_TIMEOUT;
155 static unsigned char do_smbus_read_byte(unsigned smbus_io_base, unsigned char device, unsigned char address)
157 unsigned char val, val1;
159 smbus_check_stop_condition(smbus_io_base);
161 smbus_start_condition(smbus_io_base);
163 smbus_send_slave_address(smbus_io_base, device);
165 smbus_send_command(smbus_io_base, address);
167 smbus_start_condition(smbus_io_base);
169 smbus_send_slave_address(smbus_io_base, device | 0x01);
171 /* send NACK to slave */
172 val = inb(smbus_io_base + SMB_CTRL1);
173 outb(val | SMB_CTRL1_ACK, smbus_io_base + SMB_CTRL1);
175 val = inb(smbus_io_base + SMB_SDA);
177 //smbus_stop_condition(smbus_io_base);