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c609719b WD |
1 | /* |
2 | * (C) Copyright 2002 | |
3 | * Wolfgang Denk, DENX Software Engineering, wd@denx.de. | |
4 | * | |
5 | * See file CREDITS for list of people who contributed to this | |
6 | * project. | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU General Public License as | |
10 | * published by the Free Software Foundation; either version 2 of | |
11 | * the License, or (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, | |
21 | * MA 02111-1307 USA | |
22 | */ | |
23 | ||
24 | #include <config.h> | |
25 | #include <common.h> | |
26 | #include <asm/io.h> | |
27 | ||
28 | #include "hardware.h" | |
29 | #include "i2c.h" | |
30 | ||
31 | static void i2c_start (void); | |
32 | static void i2c_stop (void); | |
33 | static int i2c_write (u8 data); | |
34 | static void i2c_read (u8 * data); | |
35 | ||
36 | static inline void i2c_port_start (void); | |
37 | static inline void i2c_clock (unsigned int val); | |
38 | static inline void i2c_data (unsigned int val); | |
39 | static inline unsigned int | |
40 | i2c_in (void); | |
41 | static inline void i2c_write_bit (unsigned int val); | |
42 | static inline unsigned int | |
43 | i2c_read_bit (void); | |
44 | ||
45 | static inline void i2c_udelay (unsigned int time); | |
46 | ||
47 | int i2c_read_byte ( | |
48 | u8 * data, | |
49 | u8 dev, | |
50 | u8 offset) | |
51 | { | |
52 | int err = 0; | |
53 | ||
54 | i2c_start(); | |
55 | ||
56 | err = ! i2c_write(dev); | |
57 | ||
58 | if (! err) | |
59 | { | |
60 | err = ! i2c_write(offset); | |
61 | } | |
62 | ||
63 | if (! err) | |
64 | { | |
65 | i2c_start(); | |
66 | } | |
67 | ||
68 | if (! err) | |
69 | { | |
70 | err = ! i2c_write(dev | 0x01); | |
71 | } | |
72 | ||
73 | if (! err) | |
74 | { | |
75 | i2c_read(data); | |
76 | } | |
77 | ||
78 | i2c_stop(); | |
79 | ||
80 | return ! err; | |
81 | } | |
82 | ||
83 | static inline void i2c_udelay ( | |
84 | unsigned int time) | |
85 | { | |
86 | int v; | |
87 | ||
6d0f6bcf | 88 | asm volatile("mtdec %0" : : "r" (time * ((CONFIG_SYS_BUS_CLK / 4) / 1000000))); |
c609719b WD |
89 | |
90 | do | |
91 | { | |
92 | asm volatile("isync; mfdec %0" : "=r" (v)); | |
93 | } while (v >= 0); | |
94 | } | |
95 | ||
96 | /* Low-level hardware access | |
97 | */ | |
98 | ||
99 | #define BIT_GPDATA 0x80000000 | |
100 | #define BIT_GPCLK 0x40000000 | |
101 | ||
102 | static inline void i2c_port_start (void) | |
103 | { | |
104 | out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) & ~(BIT_GPCLK | BIT_GPDATA)); | |
105 | out32(REG(CPC0, GPOUT), in32(REG(CPC0, GPOUT)) & ~(BIT_GPCLK | BIT_GPDATA)); | |
106 | iobarrier_rw(); | |
107 | ||
108 | i2c_udelay(1); | |
109 | } | |
110 | ||
111 | static inline void i2c_clock ( | |
112 | unsigned int val) | |
113 | { | |
114 | if (val) | |
115 | { | |
116 | out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) & ~BIT_GPCLK); | |
117 | } | |
118 | else | |
119 | { | |
120 | out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) | BIT_GPCLK); | |
121 | } | |
122 | ||
123 | iobarrier_rw(); | |
124 | ||
125 | i2c_udelay(1); | |
126 | } | |
127 | ||
128 | static inline void i2c_data ( | |
129 | unsigned int val) | |
130 | { | |
131 | if (val) | |
132 | { | |
133 | out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) & ~BIT_GPDATA); | |
134 | } | |
135 | else | |
136 | { | |
137 | out32(REG(CPC0, GPDIR), in32(REG(CPC0, GPDIR)) | BIT_GPDATA); | |
138 | } | |
139 | ||
140 | iobarrier_rw(); | |
141 | ||
142 | i2c_udelay(1); | |
143 | } | |
144 | ||
145 | static inline unsigned int i2c_in (void) | |
146 | { | |
147 | unsigned int val = ((in32(REG(CPC0, GPIN)) & BIT_GPDATA) != 0)?1:0; | |
148 | ||
149 | iobarrier_rw(); | |
150 | ||
151 | return val; | |
152 | } | |
153 | ||
154 | ||
155 | /* Protocol implementation | |
156 | */ | |
157 | ||
158 | static inline void i2c_write_bit ( | |
159 | unsigned int val) | |
160 | { | |
161 | i2c_data(val); | |
162 | i2c_udelay(10); | |
163 | i2c_clock(1); | |
164 | i2c_udelay(10); | |
165 | i2c_clock(0); | |
166 | i2c_udelay(10); | |
167 | } | |
168 | ||
169 | static inline unsigned int i2c_read_bit (void) | |
170 | { | |
171 | unsigned int val; | |
172 | ||
173 | i2c_data(1); | |
174 | i2c_udelay(10); | |
175 | ||
176 | i2c_clock(1); | |
177 | i2c_udelay(10); | |
178 | ||
179 | val = i2c_in(); | |
180 | ||
181 | i2c_clock(0); | |
182 | i2c_udelay(10); | |
183 | ||
184 | return val; | |
185 | } | |
186 | ||
187 | unsigned int i2c_reset (void) | |
188 | { | |
189 | unsigned int val; | |
190 | int i; | |
191 | ||
192 | i2c_port_start(); | |
193 | ||
194 | i=0; | |
195 | do { | |
196 | i2c_udelay(10); | |
197 | i2c_clock(0); | |
198 | i2c_udelay(10); | |
199 | i2c_clock(1); | |
200 | i2c_udelay(10); | |
201 | val = i2c_in(); | |
202 | i++; | |
203 | } while ((i<9)&&(val==0)); | |
204 | return (val); | |
205 | } | |
206 | ||
207 | ||
208 | static void i2c_start (void) | |
209 | { | |
210 | i2c_data(1); | |
211 | i2c_clock(1); | |
212 | i2c_udelay(10); | |
213 | i2c_data(0); | |
214 | i2c_udelay(10); | |
215 | i2c_clock(0); | |
216 | i2c_udelay(10); | |
217 | } | |
218 | ||
219 | static void i2c_stop (void) | |
220 | { | |
221 | i2c_data(0); | |
222 | i2c_udelay(10); | |
223 | i2c_clock(1); | |
224 | i2c_udelay(10); | |
225 | i2c_data(1); | |
226 | i2c_udelay(10); | |
227 | } | |
228 | ||
229 | static int i2c_write ( | |
230 | u8 data) | |
231 | { | |
232 | unsigned int i; | |
233 | ||
234 | for (i = 0; i < 8; i++) | |
235 | { | |
236 | i2c_write_bit(data >> 7); | |
237 | data <<= 1; | |
238 | } | |
239 | ||
240 | return i2c_read_bit() == 0; | |
241 | } | |
242 | ||
243 | static void i2c_read ( | |
244 | u8 * data) | |
245 | { | |
246 | unsigned int i; | |
247 | u8 val = 0; | |
248 | ||
249 | for (i = 0; i < 8; i++) | |
250 | { | |
251 | val <<= 1; | |
252 | val |= i2c_read_bit(); | |
253 | } | |
254 | ||
255 | *data = val; | |
256 | i2c_write_bit(1); /* NoAck */ | |
257 | } |