-
Notifications
You must be signed in to change notification settings - Fork 2
/
i2c_util.c
218 lines (171 loc) · 5.63 KB
/
i2c_util.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
/********************************************************************************
* Copyright (C) 2021 Ju, Gyeong-min
********************************************************************************/
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/kconfig.h> /// for CONFIG_HZ
#include <linux/errno.h>
#include <asm/io.h>
#include "log_util.h"
#include "i2c_util.h"
#include "bcm_peri.h"
#include "gpio_util.h"
#include "bcm2835.h"
/*
* Defines for I2C peripheral (aka BSC, or Broadcom Serial Controller)
*/
#define BSC1_C (*(bsc1 + 0x00))
#define BSC1_S (*(bsc1 + 0x01))
#define BSC1_DLEN (*(bsc1 + 0x02))
#define BSC1_A (*(bsc1 + 0x03))
#define BSC1_FIFO (*(bsc1 + 0x04))
#define BSC_C_I2CEN (1 << 15)
#define BSC_C_INTR (1 << 10)
#define BSC_C_INTT (1 << 9)
#define BSC_C_INTD (1 << 8)
#define BSC_C_ST (1 << 7)
#define BSC_C_CLEAR (1 << 4)
#define BSC_C_READ (1)
#define START_READ (BSC_C_I2CEN | BSC_C_ST | BSC_C_CLEAR | BSC_C_READ)
#define START_WRITE (BSC_C_I2CEN | BSC_C_ST)
#define BSC_S_CLKT (1 << 9)
#define BSC_S_ERR (1 << 8)
#define BSC_S_RXF (1 << 7)
#define BSC_S_TXE (1 << 6)
#define BSC_S_RXD (1 << 5)
#define BSC_S_TXD (1 << 4)
#define BSC_S_RXR (1 << 3)
#define BSC_S_TXW (1 << 2)
#define BSC_S_DONE (1 << 1)
#define BSC_S_TA (1)
#define CLEAR_STATUS (BSC_S_CLKT | BSC_S_ERR | BSC_S_DONE)
static volatile unsigned* bsc1;
static int bsc1_ref_count = 0;
//#define BSC1_BASE (PERI_BASE + 0x804000)
#define BSC1_BASE (0x804000)
int i2c_init(u32 peri_base_addr, int size)
{
if (bsc1_ref_count++ > 0) return 0;
if (size == 0) size = 0xB0;
/* Set up i2c pointer for direct register access */
if ((bsc1 = ioremap(peri_base_addr + BSC1_BASE, size)) == NULL) {
am_log_err("io remap failed.");
bsc1_ref_count--;
return -EBUSY;
}
INP_GPIO(2);
SET_GPIO_ALT(2, 0);
INP_GPIO(3);
SET_GPIO_ALT(3, 0);
return 0;
}
void i2c_close(void)
{
if (--bsc1_ref_count > 0) return;
if (bsc1 != NULL) {
iounmap(bsc1);
bsc1 = NULL;
}
}
void wait_i2c_done(void)
{
while (!(BSC1_S & BSC_S_DONE)) {
udelay(1);
}
}
// Function to write data to an I2C device via the FIFO. This doesn't refill the FIFO, so writes are limited to 16 bytes
// including the register address. len specifies the number of bytes in the buffer.
void i2c_raw_write(char dev_addr, char *buf, int len)
{
int i;
BSC1_A = dev_addr;
BSC1_DLEN = len; // one byte for the register address, plus the buffer length
for (i = 0; i < len; i++) {
BSC1_FIFO = buf[i];
}
BSC1_S = CLEAR_STATUS; // Reset status bits (see #define)
BSC1_C = START_WRITE; // Start Write (see #define)
wait_i2c_done();
// BSC1_S = CLEAR_STATUS; // Reset status bits (see #define)
}
// Function to read a number of bytes into a buffer from the FIFO of the I2C controller
void i2c_raw_read(char dev_addr, char *buf, int len)
{
int bufidx;
BSC1_DLEN = (unsigned char)len;
BSC1_S = CLEAR_STATUS; // Reset status bits (see #define)
BSC1_C = START_READ; // Start Read after clearing FIFO (see #define)
bufidx = 0;
while (!(BSC1_S & BSC_S_DONE)) {
// Wait for some data to appear in the FIFO
while ((BSC1_S & BSC_S_TA) && !(BSC1_S & BSC_S_RXD));
// Consume the FIFO
while ((BSC1_S & BSC_S_RXD) && (bufidx < len)) {
buf[bufidx++] = BSC1_FIFO;
}
}
wait_i2c_done();
// BSC1_S = CLEAR_STATUS; // Reset status bits (see #define)
}
// Function to write data to an I2C device via the FIFO. This doesn't refill the FIFO, so writes are limited to 16 bytes
// including the register address. len specifies the number of bytes in the buffer.
void i2c_write(char dev_addr, char reg_addr, char *buf, int len)
{
int i;
BSC1_A = dev_addr;
BSC1_DLEN = len + 1; // one byte for the register address, plus the buffer length
BSC1_FIFO = reg_addr; // start register address
for (i = 0; i < len; i++) {
BSC1_FIFO = buf[i];
}
BSC1_S = CLEAR_STATUS; // Reset status bits (see #define)
BSC1_C = START_WRITE; // Start Write (see #define)
wait_i2c_done();
// BSC1_S = CLEAR_STATUS; // Reset status bits (see #define)
}
// Function to read a number of bytes into a buffer from the FIFO of the I2C controller
void i2c_read(char dev_addr, char reg_addr, char *buf, int len)
{
i2c_raw_write(dev_addr, ®_addr, sizeof(char));
i2c_raw_read(dev_addr, buf, len);
}
void i2c_write_1byte(char dev_addr, char reg_addr, char value)
{
i2c_write(dev_addr, reg_addr, &value, sizeof(char));
}
void i2c_write_1word(char dev_addr, char reg_addr, short value)
{
i2c_write(dev_addr, reg_addr, (char *)&value, sizeof(short));
}
void i2c_raw_write_1byte(char dev_addr, char value)
{
i2c_raw_write(dev_addr, &value, sizeof(char));
}
void i2c_raw_write_1word(char dev_addr, short value)
{
i2c_raw_write(dev_addr, (char *)&value, sizeof(short));
}
char i2c_read_1byte(char dev_addr, char reg_addr)
{
char value;
i2c_read(dev_addr, reg_addr, &value, 1);
return value;
}
short i2c_read_1word(char dev_addr, char reg_addr)
{
short value;
i2c_read(dev_addr, reg_addr, (char *)&value, sizeof(short));
return value;
}
char i2c_raw_read_1byte(char dev_addr)
{
char value;
i2c_raw_read(dev_addr, &value, 1);
return value;
}
short i2c_raw_read_1word(char dev_addr)
{
short value;
i2c_raw_read(dev_addr, (char *)&value, sizeof(short));
return value;
}