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wdenk232c1502004-03-12 00:14:09 +00001/*
2 * Basic I2C functions
3 *
4 * Copyright (c) 2003 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 */
20
21#include <common.h>
22
wdenk232c1502004-03-12 00:14:09 +000023static void wait_for_bb (void);
24static u16 wait_for_pin (void);
25
26void i2c_init (int speed, int slaveadd)
27{
28 u16 scl;
29
30 if (inw (I2C_CON) & I2C_CON_EN) {
31 outw (0, I2C_CON);
32 udelay (5000);
33 }
34
Wolfgang Denk8ed44d92008-10-19 02:35:50 +020035 /* 12MHz I2C module clock */
wdenk232c1502004-03-12 00:14:09 +000036 outw (0, I2C_PSC);
37 outw (I2C_CON_EN, I2C_CON);
38 outw (0, I2C_SYSTEST);
39 /* have to enable intrrupts or OMAP i2c module doesn't work */
40 outw (I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE |
41 I2C_IE_NACK_IE | I2C_IE_AL_IE, I2C_IE);
42 scl = (12000000 / 2) / speed - 6;
43 outw (scl, I2C_SCLL);
44 outw (scl, I2C_SCLH);
45 /* own address */
46 outw (slaveadd, I2C_OA);
47 outw (0, I2C_CNT);
48 udelay (1000);
49}
50
51static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value)
52{
53 int i2c_error = 0;
54 u16 status;
55
56 /* wait until bus not busy */
57 wait_for_bb ();
58
59 /* one byte only */
60 outw (1, I2C_CNT);
61 /* set slave address */
62 outw (devaddr, I2C_SA);
63 /* no stop bit needed here */
64 outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX, I2C_CON);
65
66 status = wait_for_pin ();
67
68 if (status & I2C_STAT_XRDY) {
69 /* Important: have to use byte access */
70 *(volatile u8 *) (I2C_DATA) = regoffset;
71 udelay (20000);
72 if (inw (I2C_STAT) & I2C_STAT_NACK) {
73 i2c_error = 1;
74 }
75 } else {
76 i2c_error = 1;
77 }
78
79 if (!i2c_error) {
80 /* free bus, otherwise we can't use a combined transction */
81 outw (0, I2C_CON);
82 while (inw (I2C_STAT) || (inw (I2C_CON) & I2C_CON_MST)) {
83 udelay (10000);
84 /* Have to clear pending interrupt to clear I2C_STAT */
85 inw (I2C_IV);
86 }
87
88 wait_for_bb ();
89 /* set slave address */
90 outw (devaddr, I2C_SA);
91 /* read one byte from slave */
92 outw (1, I2C_CNT);
93 /* need stop bit here */
94 outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP,
95 I2C_CON);
96
97 status = wait_for_pin ();
98 if (status & I2C_STAT_RRDY) {
99 *value = inw (I2C_DATA);
100 udelay (20000);
101 } else {
102 i2c_error = 1;
103 }
104
105 if (!i2c_error) {
106 outw (I2C_CON_EN, I2C_CON);
107 while (inw (I2C_STAT)
108 || (inw (I2C_CON) & I2C_CON_MST)) {
109 udelay (10000);
110 inw (I2C_IV);
111 }
112 }
113 }
114
115 return i2c_error;
116}
117
118static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value)
119{
120 int i2c_error = 0;
121 u16 status;
122
123 /* wait until bus not busy */
124 wait_for_bb ();
125
126 /* two bytes */
127 outw (2, I2C_CNT);
128 /* set slave address */
129 outw (devaddr, I2C_SA);
130 /* stop bit needed here */
131 outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
132 I2C_CON_STP, I2C_CON);
133
134 /* wait until state change */
135 status = wait_for_pin ();
136
137 if (status & I2C_STAT_XRDY) {
138 /* send out two bytes */
139 outw ((value << 8) + regoffset, I2C_DATA);
140 /* must have enough delay to allow BB bit to go low */
141 udelay (30000);
142 if (inw (I2C_STAT) & I2C_STAT_NACK) {
143 i2c_error = 1;
144 }
145 } else {
146 i2c_error = 1;
147 }
148
149 if (!i2c_error) {
150 outw (I2C_CON_EN, I2C_CON);
151 while (inw (I2C_STAT) || (inw (I2C_CON) & I2C_CON_MST)) {
152 udelay (1000);
153 /* have to read to clear intrrupt */
154 inw (I2C_IV);
155 }
156 }
157
158 return i2c_error;
159}
160
161int i2c_probe (uchar chip)
162{
163 int res = 1;
164
165 if (chip == inw (I2C_OA)) {
166 return res;
167 }
168
169 /* wait until bus not busy */
170 wait_for_bb ();
171
172 /* try to read one byte */
173 outw (1, I2C_CNT);
174 /* set slave address */
175 outw (chip, I2C_SA);
176 /* stop bit needed here */
177 outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, I2C_CON);
178 /* enough delay for the NACK bit set */
179 udelay (2000);
180 if (!(inw (I2C_STAT) & I2C_STAT_NACK)) {
181 res = 0;
182 } else {
183 outw (inw (I2C_CON) | I2C_CON_STP, I2C_CON);
184 udelay (20);
185 wait_for_bb ();
186 }
187
188 return res;
189}
190
191int i2c_read (uchar chip, uint addr, int alen, uchar * buffer, int len)
192{
193 int i;
194
195 if (alen > 1) {
196 printf ("I2C read: addr len %d not supported\n", alen);
197 return 1;
198 }
199
200 if (addr + len > 256) {
201 printf ("I2C read: address out of range\n");
202 return 1;
203 }
204
205 for (i = 0; i < len; i++) {
206 if (i2c_read_byte (chip, addr + i, &buffer[i])) {
207 printf ("I2C read: I/O error\n");
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200208 i2c_init (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
wdenk232c1502004-03-12 00:14:09 +0000209 return 1;
210 }
211 }
212
213 return 0;
214}
215
216int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len)
217{
218 int i;
219
220 if (alen > 1) {
221 printf ("I2C read: addr len %d not supported\n", alen);
222 return 1;
223 }
224
225 if (addr + len > 256) {
226 printf ("I2C read: address out of range\n");
227 return 1;
228 }
229
230 for (i = 0; i < len; i++) {
231 if (i2c_write_byte (chip, addr + i, buffer[i])) {
232 printf ("I2C read: I/O error\n");
Jean-Christophe PLAGNIOL-VILLARD6d0f6bc2008-10-16 15:01:15 +0200233 i2c_init (CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
wdenk232c1502004-03-12 00:14:09 +0000234 return 1;
235 }
236 }
237
238 return 0;
239}
240
241static void wait_for_bb (void)
242{
243 int timeout = 10;
244
245 while ((inw (I2C_STAT) & I2C_STAT_BB) && timeout--) {
246 inw (I2C_IV);
247 udelay (1000);
248 }
249
250 if (timeout <= 0) {
251 printf ("timed out in wait_for_bb: I2C_STAT=%x\n",
252 inw (I2C_STAT));
253 }
254}
255
256static u16 wait_for_pin (void)
257{
258 u16 status, iv;
259 int timeout = 10;
260
261 do {
262 udelay (1000);
263 status = inw (I2C_STAT);
264 iv = inw (I2C_IV);
265 } while (!iv &&
266 !(status &
267 (I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY |
268 I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK |
269 I2C_STAT_AL)) && timeout--);
270
271 if (timeout <= 0) {
272 printf ("timed out in wait_for_pin: I2C_STAT=%x\n",
273 inw (I2C_STAT));
274 }
275
276 return status;
277}