blob: 942f32b91d12da6a803e4c9da3edea54a29f3f23 (
plain)
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
|
/*
* Atmel AT93C46 serial eeprom driver
*
* Brian Murphy <brian.murphy@eicon.com>
*
*/
#include <linux/kernel.h>
#include <linux/delay.h>
#include <asm/lasat/lasat.h>
#include <linux/module.h>
#include "at93c.h"
#define AT93C_ADDR_SHIFT 7
#define AT93C_ADDR_MAX ((1 << AT93C_ADDR_SHIFT) - 1)
#define AT93C_RCMD (0x6 << AT93C_ADDR_SHIFT)
#define AT93C_WCMD (0x5 << AT93C_ADDR_SHIFT)
#define AT93C_WENCMD 0x260
#define AT93C_WDSCMD 0x200
struct at93c_defs *at93c;
static void at93c_reg_write(u32 val)
{
*at93c->reg = val;
}
static u32 at93c_reg_read(void)
{
u32 tmp = *at93c->reg;
return tmp;
}
static u32 at93c_datareg_read(void)
{
u32 tmp = *at93c->rdata_reg;
return tmp;
}
static void at93c_cycle_clk(u32 data)
{
at93c_reg_write(data | at93c->clk);
lasat_ndelay(250);
at93c_reg_write(data & ~at93c->clk);
lasat_ndelay(250);
}
static void at93c_write_databit(u8 bit)
{
u32 data = at93c_reg_read();
if (bit)
data |= 1 << at93c->wdata_shift;
else
data &= ~(1 << at93c->wdata_shift);
at93c_reg_write(data);
lasat_ndelay(100);
at93c_cycle_clk(data);
}
static unsigned int at93c_read_databit(void)
{
u32 data;
at93c_cycle_clk(at93c_reg_read());
data = (at93c_datareg_read() >> at93c->rdata_shift) & 1;
return data;
}
static u8 at93c_read_byte(void)
{
int i;
u8 data = 0;
for (i = 0; i <= 7; i++) {
data <<= 1;
data |= at93c_read_databit();
}
return data;
}
static void at93c_write_bits(u32 data, int size)
{
int i;
int shift = size - 1;
u32 mask = (1 << shift);
for (i = 0; i < size; i++) {
at93c_write_databit((data & mask) >> shift);
data <<= 1;
}
}
static void at93c_init_op(void)
{
at93c_reg_write((at93c_reg_read() | at93c->cs) &
~at93c->clk & ~(1 << at93c->rdata_shift));
lasat_ndelay(50);
}
static void at93c_end_op(void)
{
at93c_reg_write(at93c_reg_read() & ~at93c->cs);
lasat_ndelay(250);
}
static void at93c_wait(void)
{
at93c_init_op();
while (!at93c_read_databit())
;
at93c_end_op();
};
static void at93c_disable_wp(void)
{
at93c_init_op();
at93c_write_bits(AT93C_WENCMD, 10);
at93c_end_op();
}
static void at93c_enable_wp(void)
{
at93c_init_op();
at93c_write_bits(AT93C_WDSCMD, 10);
at93c_end_op();
}
u8 at93c_read(u8 addr)
{
u8 byte;
at93c_init_op();
at93c_write_bits((addr & AT93C_ADDR_MAX)|AT93C_RCMD, 10);
byte = at93c_read_byte();
at93c_end_op();
return byte;
}
void at93c_write(u8 addr, u8 data)
{
at93c_disable_wp();
at93c_init_op();
at93c_write_bits((addr & AT93C_ADDR_MAX)|AT93C_WCMD, 10);
at93c_write_bits(data, 8);
at93c_end_op();
at93c_wait();
at93c_enable_wp();
}
|
