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wdenk8ed96042005-01-09 23:16:25 +00001/*
2 * Basic I2C functions
3 *
4 * Copyright (c) 2004 Texas Instruments
5 *
6 * This package is free software; you can redistribute it and/or
7 * modify it under the terms of the license found in the file
8 * named COPYING that should have accompanied this file.
9 *
10 * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
11 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
12 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
13 *
14 * Author: Jian Zhang jzhang@ti.com, Texas Instruments
15 *
16 * Copyright (c) 2003 Wolfgang Denk, wd@denx.de
17 * Rewritten to fit into the current U-Boot framework
18 *
19 * Adapted for OMAP2420 I2C, r-woodruff2@ti.com
20 *
21 */
22
23#include <common.h>
wdenk289f9322005-01-12 00:15:14 +000024
wdenk8ed96042005-01-09 23:16:25 +000025#include <asm/arch/i2c.h>
26#include <asm/io.h>
27
28#define inw(a) __raw_readw(a)
29#define outw(a,v) __raw_writew(a,v)
30
wdenk8ed96042005-01-09 23:16:25 +000031static void wait_for_bb (void);
32static u16 wait_for_pin (void);
Wolfgang Denk49a75812005-09-25 18:41:04 +020033static void flush_fifo(void);
wdenk8ed96042005-01-09 23:16:25 +000034
35void i2c_init (int speed, int slaveadd)
36{
37 u16 scl;
38
Wolfgang Denk49a75812005-09-25 18:41:04 +020039 outw(0x2, I2C_SYSC); /* for ES2 after soft reset */
40 udelay(1000);
41 outw(0x0, I2C_SYSC); /* will probably self clear but */
42
wdenk8ed96042005-01-09 23:16:25 +000043 if (inw (I2C_CON) & I2C_CON_EN) {
44 outw (0, I2C_CON);
45 udelay (50000);
46 }
47
48 /* 12Mhz I2C module clock */
49 outw (0, I2C_PSC);
wdenk082acfd2005-01-10 00:01:04 +000050 speed = speed/1000; /* 100 or 400 */
51 scl = ((12000/(speed*2)) - 7); /* use 7 when PSC = 0 */
wdenk8ed96042005-01-09 23:16:25 +000052 outw (scl, I2C_SCLL);
53 outw (scl, I2C_SCLH);
54 /* own address */
55 outw (slaveadd, I2C_OA);
56 outw (I2C_CON_EN, I2C_CON);
Wolfgang Denk49a75812005-09-25 18:41:04 +020057
wdenk8ed96042005-01-09 23:16:25 +000058 /* have to enable intrrupts or OMAP i2c module doesn't work */
59 outw (I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE |
60 I2C_IE_NACK_IE | I2C_IE_AL_IE, I2C_IE);
61 udelay (1000);
Wolfgang Denk49a75812005-09-25 18:41:04 +020062 flush_fifo();
63 outw (0xFFFF, I2C_STAT);
64 outw (0, I2C_CNT);
wdenk8ed96042005-01-09 23:16:25 +000065}
66
67static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value)
68{
69 int i2c_error = 0;
70 u16 status;
71
72 /* wait until bus not busy */
73 wait_for_bb ();
74
75 /* one byte only */
76 outw (1, I2C_CNT);
77 /* set slave address */
78 outw (devaddr, I2C_SA);
79 /* no stop bit needed here */
80 outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX, I2C_CON);
81
82 status = wait_for_pin ();
83
84 if (status & I2C_STAT_XRDY) {
85 /* Important: have to use byte access */
86 *(volatile u8 *) (I2C_DATA) = regoffset;
87 udelay (20000);
88 if (inw (I2C_STAT) & I2C_STAT_NACK) {
89 i2c_error = 1;
90 }
91 } else {
92 i2c_error = 1;
93 }
94
95 if (!i2c_error) {
96 /* free bus, otherwise we can't use a combined transction */
97 outw (0, I2C_CON);
98 while (inw (I2C_STAT) || (inw (I2C_CON) & I2C_CON_MST)) {
99 udelay (10000);
100 /* Have to clear pending interrupt to clear I2C_STAT */
101 outw (0xFFFF, I2C_STAT);
102 }
103
104 wait_for_bb ();
105 /* set slave address */
106 outw (devaddr, I2C_SA);
107 /* read one byte from slave */
108 outw (1, I2C_CNT);
109 /* need stop bit here */
110 outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP,
111 I2C_CON);
112
113 status = wait_for_pin ();
114 if (status & I2C_STAT_RRDY) {
115 *value = inw (I2C_DATA);
116 udelay (20000);
117 } else {
118 i2c_error = 1;
119 }
120
121 if (!i2c_error) {
122 outw (I2C_CON_EN, I2C_CON);
123 while (inw (I2C_STAT)
124 || (inw (I2C_CON) & I2C_CON_MST)) {
125 udelay (10000);
126 outw (0xFFFF, I2C_STAT);
127 }
128 }
129 }
130 flush_fifo();
131 outw (0xFFFF, I2C_STAT);
132 outw (0, I2C_CNT);
133 return i2c_error;
134}
135
136static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value)
137{
138 int i2c_error = 0;
139 u16 status, stat;
140
141 /* wait until bus not busy */
142 wait_for_bb ();
143
144 /* two bytes */
145 outw (2, I2C_CNT);
146 /* set slave address */
147 outw (devaddr, I2C_SA);
148 /* stop bit needed here */
149 outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
150 I2C_CON_STP, I2C_CON);
151
152 /* wait until state change */
153 status = wait_for_pin ();
154
155 if (status & I2C_STAT_XRDY) {
156 /* send out two bytes */
157 outw ((value << 8) + regoffset, I2C_DATA);
158 /* must have enough delay to allow BB bit to go low */
159 udelay (50000);
160 if (inw (I2C_STAT) & I2C_STAT_NACK) {
161 i2c_error = 1;
162 }
163 } else {
164 i2c_error = 1;
165 }
166
167 if (!i2c_error) {
Wolfgang Denk49a75812005-09-25 18:41:04 +0200168 int eout = 200;
169
wdenk8ed96042005-01-09 23:16:25 +0000170 outw (I2C_CON_EN, I2C_CON);
171 while ((stat = inw (I2C_STAT)) || (inw (I2C_CON) & I2C_CON_MST)) {
172 udelay (1000);
173 /* have to read to clear intrrupt */
174 outw (0xFFFF, I2C_STAT);
Wolfgang Denk49a75812005-09-25 18:41:04 +0200175 if(--eout == 0) /* better leave with error than hang */
176 break;
wdenk8ed96042005-01-09 23:16:25 +0000177 }
178 }
179 flush_fifo();
180 outw (0xFFFF, I2C_STAT);
181 outw (0, I2C_CNT);
182 return i2c_error;
183}
184
Wolfgang Denk49a75812005-09-25 18:41:04 +0200185static void flush_fifo(void)
wdenk8ed96042005-01-09 23:16:25 +0000186{ u16 stat;
wdenk082acfd2005-01-10 00:01:04 +0000187
188 /* note: if you try and read data when its not there or ready
189 * you get a bus error
190 */
wdenk8ed96042005-01-09 23:16:25 +0000191 while(1){
192 stat = inw(I2C_STAT);
193 if(stat == I2C_STAT_RRDY){
194 inw(I2C_DATA);
195 outw(I2C_STAT_RRDY,I2C_STAT);
196 udelay(1000);
197 }else
198 break;
199 }
200}
201
202int i2c_probe (uchar chip)
203{
204 int res = 1; /* default = fail */
205
206 if (chip == inw (I2C_OA)) {
207 return res;
208 }
209
210 /* wait until bus not busy */
211 wait_for_bb ();
212
213 /* try to read one byte */
214 outw (1, I2C_CNT);
215 /* set slave address */
216 outw (chip, I2C_SA);
217 /* stop bit needed here */
218 outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, I2C_CON);
219 /* enough delay for the NACK bit set */
220 udelay (50000);
221
222 if (!(inw (I2C_STAT) & I2C_STAT_NACK)) {
wdenk082acfd2005-01-10 00:01:04 +0000223 res = 0; /* success case */
wdenk8ed96042005-01-09 23:16:25 +0000224 flush_fifo();
225 outw(0xFFFF, I2C_STAT);
226 } else {
wdenk082acfd2005-01-10 00:01:04 +0000227 outw(0xFFFF, I2C_STAT); /* failue, clear sources*/
wdenk8ed96042005-01-09 23:16:25 +0000228 outw (inw (I2C_CON) | I2C_CON_STP, I2C_CON); /* finish up xfer */
229 udelay(20000);
230 wait_for_bb ();
231 }
232 flush_fifo();
233 outw (0, I2C_CNT); /* don't allow any more data in...we don't want it.*/
234 outw(0xFFFF, I2C_STAT);
235 return res;
236}
237
238int i2c_read (uchar chip, uint addr, int alen, uchar * buffer, int len)
239{
240 int i;
241
242 if (alen > 1) {
243 printf ("I2C read: addr len %d not supported\n", alen);
244 return 1;
245 }
246
247 if (addr + len > 256) {
248 printf ("I2C read: address out of range\n");
249 return 1;
250 }
251
252 for (i = 0; i < len; i++) {
253 if (i2c_read_byte (chip, addr + i, &buffer[i])) {
254 printf ("I2C read: I/O error\n");
255 i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE);
256 return 1;
257 }
258 }
259
260 return 0;
261}
262
263int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len)
264{
265 int i;
266
267 if (alen > 1) {
268 printf ("I2C read: addr len %d not supported\n", alen);
269 return 1;
270 }
271
272 if (addr + len > 256) {
273 printf ("I2C read: address out of range\n");
274 return 1;
275 }
276
277 for (i = 0; i < len; i++) {
278 if (i2c_write_byte (chip, addr + i, buffer[i])) {
279 printf ("I2C read: I/O error\n");
280 i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE);
281 return 1;
282 }
283 }
284
285 return 0;
286}
287
288static void wait_for_bb (void)
289{
290 int timeout = 10;
291 u16 stat;
292
wdenk082acfd2005-01-10 00:01:04 +0000293 outw(0xFFFF, I2C_STAT); /* clear current interruts...*/
wdenk8ed96042005-01-09 23:16:25 +0000294 while ((stat = inw (I2C_STAT) & I2C_STAT_BB) && timeout--) {
295 outw (stat, I2C_STAT);
296 udelay (50000);
297 }
298
299 if (timeout <= 0) {
300 printf ("timed out in wait_for_bb: I2C_STAT=%x\n",
301 inw (I2C_STAT));
302 }
wdenk082acfd2005-01-10 00:01:04 +0000303 outw(0xFFFF, I2C_STAT); /* clear delayed stuff*/
wdenk8ed96042005-01-09 23:16:25 +0000304}
305
306static u16 wait_for_pin (void)
307{
308 u16 status;
309 int timeout = 10;
310
311 do {
312 udelay (1000);
313 status = inw (I2C_STAT);
314 } while ( !(status &
315 (I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY |
316 I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK |
317 I2C_STAT_AL)) && timeout--);
318
319 if (timeout <= 0) {
320 printf ("timed out in wait_for_pin: I2C_STAT=%x\n",
321 inw (I2C_STAT));
wdenk082acfd2005-01-10 00:01:04 +0000322 outw(0xFFFF, I2C_STAT);
wdenk8ed96042005-01-09 23:16:25 +0000323}
324 return status;
325}