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[/] [or1k_old/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [armnommu/] [kernel/] [iic.c] - Blame information for rev 1782

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/*
 * linux/arch/arm/kernel/iic.c
 *
 * Copyright (C) 1995, 1996 Russell King
 *
 * IIC is used to get the current time from the CMOS rtc.
 */
 
#include <asm/system.h>
#include <asm/delay.h>
#include <asm/io.h>
#include <asm/hardware.h>
 
#define FORCE_ONES      0xdc
 
/*
 * if delay loop has been calibrated then us that,
 * else use IOC timer 1.
 */
static void iic_delay (void)
{
        extern unsigned long loops_per_sec;
        if (loops_per_sec != (1 << 12)) {
                udelay(10);
                return;
        } else {
                unsigned long flags;
                save_flags_cli(flags);
 
                outb(254,  IOC_T1LTCHL);
                outb(255,  IOC_T1LTCHH);
                outb(0,    IOC_T1GO);
                outb(1<<6, IOC_IRQCLRA);                        /* clear T1 irq */
                outb(4,    IOC_T1LTCHL);
                outb(0,    IOC_T1LTCHH);
                outb(0,    IOC_T1GO);
                while ((inb(IOC_IRQSTATA) & (1<<6)) == 0);
                restore_flags(flags);
        }
}
 
static inline void iic_start (void)
{
        unsigned char out;
 
        out = inb(IOC_CONTROL) | FORCE_ONES | 0x02;
 
        outb(out, IOC_CONTROL);
        iic_delay();
 
        outb(out ^ 1, IOC_CONTROL);
        iic_delay();
}
 
static inline void iic_stop (void)
{
        unsigned char out;
 
        out = inb(IOC_CONTROL) | FORCE_ONES | 0x03;
 
        iic_delay();
        outb(out ^ 1, IOC_CONTROL);
 
        iic_delay();
        outb(out, IOC_CONTROL);
}
 
static int iic_sendbyte (unsigned char b)
{
        unsigned char out, in;
        int i;
 
        out = (inb(IOC_CONTROL) & 0xfc) | FORCE_ONES;
 
        outb(out, IOC_CONTROL);
        for (i = 7; i >= 0; i--) {
                unsigned char c;
                c = out | ((b & (1 << i)) ? 1 : 0);
 
                outb(c, IOC_CONTROL);
                iic_delay();
 
                outb(c | 2, IOC_CONTROL);
                iic_delay();
 
                outb(c, IOC_CONTROL);
        }
        outb(out | 1, IOC_CONTROL);
        iic_delay();
 
        outb(out | 3, IOC_CONTROL);
        iic_delay();
 
        in = inb(IOC_CONTROL) & 1;
 
        outb(out | 1, IOC_CONTROL);
        iic_delay();
 
        outb(out, IOC_CONTROL);
        iic_delay();
 
        if(in) {
                printk("No acknowledge from RTC\n");
                return 1;
        } else
                return 0;
}
 
static unsigned char iic_recvbyte (void)
{
        unsigned char out, in;
        int i;
 
        out = (inb(IOC_CONTROL) & 0xfc) | FORCE_ONES;
 
        outb(out, IOC_CONTROL);
        in = 0;
        for (i = 7; i >= 0; i--) {
                outb(out | 1, IOC_CONTROL);
                iic_delay();
                outb(out | 3, IOC_CONTROL);
                iic_delay();
                in = (in << 1) | (inb(IOC_CONTROL) & 1);
                outb(out | 1, IOC_CONTROL);
                iic_delay();
        }
        outb(out, IOC_CONTROL);
        iic_delay();
        outb(out | 2, IOC_CONTROL);
        iic_delay();
 
        return in;
}
 
void iic_control (unsigned char addr, unsigned char loc, unsigned char *buf, int len)
{
        iic_start();
 
        if (iic_sendbyte(addr & 0xfe))
                goto error;
 
        if (iic_sendbyte(loc))
                goto error;
 
        if (addr & 1) {
                int i;
 
                for (i = 0; i < len; i++)
                        if (iic_sendbyte (buf[i]))
                                break;
        } else {
                int i;
 
                iic_stop();
                iic_start();
                iic_sendbyte(addr|1);
                for (i = 0; i < len; i++)
                        buf[i] = iic_recvbyte ();
        }
error:
        iic_stop();
}

Line No.	Rev	Author	Line
1	1622	jcastillo	`/*`
2			`* linux/arch/arm/kernel/iic.c`
3			`*`
4			`* Copyright (C) 1995, 1996 Russell King`
5			`*`
6			`* IIC is used to get the current time from the CMOS rtc.`
7			`*/`
8
9			`#include <asm/system.h>`
10			`#include <asm/delay.h>`
11			`#include <asm/io.h>`
12			`#include <asm/hardware.h>`
13
14			`#define FORCE_ONES 0xdc`
15
16			`/*`
17			`* if delay loop has been calibrated then us that,`
18			`* else use IOC timer 1.`
19			`*/`
20			`static void iic_delay (void)`
21			`{`
22			`extern unsigned long loops_per_sec;`
23			`if (loops_per_sec != (1 << 12)) {`
24			`udelay(10);`
25			`return;`
26			`} else {`
27			`unsigned long flags;`
28			`save_flags_cli(flags);`
29
30			`outb(254, IOC_T1LTCHL);`
31			`outb(255, IOC_T1LTCHH);`
32			`outb(0, IOC_T1GO);`
33			`outb(1<<6, IOC_IRQCLRA); /* clear T1 irq */`
34			`outb(4, IOC_T1LTCHL);`
35			`outb(0, IOC_T1LTCHH);`
36			`outb(0, IOC_T1GO);`
37			`while ((inb(IOC_IRQSTATA) & (1<<6)) == 0);`
38			`restore_flags(flags);`
39			`}`
40			`}`
41
42			`static inline void iic_start (void)`
43			`{`
44			`unsigned char out;`
45
46			`out = inb(IOC_CONTROL) \| FORCE_ONES \| 0x02;`
47
48			`outb(out, IOC_CONTROL);`
49			`iic_delay();`
50
51			`outb(out ^ 1, IOC_CONTROL);`
52			`iic_delay();`
53			`}`
54
55			`static inline void iic_stop (void)`
56			`{`
57			`unsigned char out;`
58
59			`out = inb(IOC_CONTROL) \| FORCE_ONES \| 0x03;`
60
61			`iic_delay();`
62			`outb(out ^ 1, IOC_CONTROL);`
63
64			`iic_delay();`
65			`outb(out, IOC_CONTROL);`
66			`}`
67
68			`static int iic_sendbyte (unsigned char b)`
69			`{`
70			`unsigned char out, in;`
71			`int i;`
72
73			`out = (inb(IOC_CONTROL) & 0xfc) \| FORCE_ONES;`
74
75			`outb(out, IOC_CONTROL);`
76			`for (i = 7; i >= 0; i--) {`
77			`unsigned char c;`
78			`c = out \| ((b & (1 << i)) ? 1 : 0);`
79
80			`outb(c, IOC_CONTROL);`
81			`iic_delay();`
82
83			`outb(c \| 2, IOC_CONTROL);`
84			`iic_delay();`
85
86			`outb(c, IOC_CONTROL);`
87			`}`
88			`outb(out \| 1, IOC_CONTROL);`
89			`iic_delay();`
90
91			`outb(out \| 3, IOC_CONTROL);`
92			`iic_delay();`
93
94			`in = inb(IOC_CONTROL) & 1;`
95
96			`outb(out \| 1, IOC_CONTROL);`
97			`iic_delay();`
98
99			`outb(out, IOC_CONTROL);`
100			`iic_delay();`
101
102			`if(in) {`
103			`printk("No acknowledge from RTC\n");`
104			`return 1;`
105			`} else`
106			`return 0;`
107			`}`
108
109			`static unsigned char iic_recvbyte (void)`
110			`{`
111			`unsigned char out, in;`
112			`int i;`
113
114			`out = (inb(IOC_CONTROL) & 0xfc) \| FORCE_ONES;`
115
116			`outb(out, IOC_CONTROL);`
117			`in = 0;`
118			`for (i = 7; i >= 0; i--) {`
119			`outb(out \| 1, IOC_CONTROL);`
120			`iic_delay();`
121			`outb(out \| 3, IOC_CONTROL);`
122			`iic_delay();`
123			`in = (in << 1) \| (inb(IOC_CONTROL) & 1);`
124			`outb(out \| 1, IOC_CONTROL);`
125			`iic_delay();`
126			`}`
127			`outb(out, IOC_CONTROL);`
128			`iic_delay();`
129			`outb(out \| 2, IOC_CONTROL);`
130			`iic_delay();`
131
132			`return in;`
133			`}`
134
135			`void iic_control (unsigned char addr, unsigned char loc, unsigned char *buf, int len)`
136			`{`
137			`iic_start();`
138
139			`if (iic_sendbyte(addr & 0xfe))`
140			`goto error;`
141
142			`if (iic_sendbyte(loc))`
143			`goto error;`
144
145			`if (addr & 1) {`
146			`int i;`
147
148			`for (i = 0; i < len; i++)`
149			`if (iic_sendbyte (buf[i]))`
150			`break;`
151			`} else {`
152			`int i;`
153
154			`iic_stop();`
155			`iic_start();`
156			`iic_sendbyte(addr\|1);`
157			`for (i = 0; i < len; i++)`
158			`buf[i] = iic_recvbyte ();`
159			`}`
160			`error:`
161			`iic_stop();`
162			`}`

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[/] [or1k_old/] [trunk/] [rc203soc/] [sw/] [uClinux/] [arch/] [armnommu/] [kernel/] [iic.c] - Blame information for rev 1782