4 * Copyright (c) 2004 Texas Instruments
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.
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.
14 * Author: Jian Zhang jzhang@ti.com, Texas Instruments
16 * Copyright (c) 2003 Wolfgang Denk, wd@denx.de
17 * Rewritten to fit into the current U-Boot framework
19 * Adapted for OMAP2420 I2C, r-woodruff2@ti.com
24 #include <asm/arch/i2c.h>
27 #define inw(a) __raw_readw(a)
28 #define outw(a,v) __raw_writew(a,v)
30 #ifdef CONFIG_DRIVER_OMAP24XX_I2C
32 static void wait_for_bb (void);
33 static u16 wait_for_pin (void);
34 void flush_fifo(void);
36 void i2c_init (int speed, int slaveadd)
40 if (inw (I2C_CON) & I2C_CON_EN) {
45 /* 12Mhz I2C module clock */
47 speed = speed/1000; /* 100 or 400 */
48 scl = ((12000/(speed*2)) - 7); /* use 7 when PSC = 0 */
52 outw (slaveadd, I2C_OA);
53 outw (I2C_CON_EN, I2C_CON);
55 /* have to enable intrrupts or OMAP i2c module doesn't work */
56 outw (I2C_IE_XRDY_IE | I2C_IE_RRDY_IE | I2C_IE_ARDY_IE |
57 I2C_IE_NACK_IE | I2C_IE_AL_IE, I2C_IE);
61 static int i2c_read_byte (u8 devaddr, u8 regoffset, u8 * value)
66 /* wait until bus not busy */
71 /* set slave address */
72 outw (devaddr, I2C_SA);
73 /* no stop bit needed here */
74 outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX, I2C_CON);
76 status = wait_for_pin ();
78 if (status & I2C_STAT_XRDY) {
79 /* Important: have to use byte access */
80 *(volatile u8 *) (I2C_DATA) = regoffset;
82 if (inw (I2C_STAT) & I2C_STAT_NACK) {
90 /* free bus, otherwise we can't use a combined transction */
92 while (inw (I2C_STAT) || (inw (I2C_CON) & I2C_CON_MST)) {
94 /* Have to clear pending interrupt to clear I2C_STAT */
95 outw (0xFFFF, I2C_STAT);
99 /* set slave address */
100 outw (devaddr, I2C_SA);
101 /* read one byte from slave */
103 /* need stop bit here */
104 outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP,
107 status = wait_for_pin ();
108 if (status & I2C_STAT_RRDY) {
109 *value = inw (I2C_DATA);
116 outw (I2C_CON_EN, I2C_CON);
117 while (inw (I2C_STAT)
118 || (inw (I2C_CON) & I2C_CON_MST)) {
120 outw (0xFFFF, I2C_STAT);
125 outw (0xFFFF, I2C_STAT);
130 static int i2c_write_byte (u8 devaddr, u8 regoffset, u8 value)
135 /* wait until bus not busy */
140 /* set slave address */
141 outw (devaddr, I2C_SA);
142 /* stop bit needed here */
143 outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX |
144 I2C_CON_STP, I2C_CON);
146 /* wait until state change */
147 status = wait_for_pin ();
149 if (status & I2C_STAT_XRDY) {
150 /* send out two bytes */
151 outw ((value << 8) + regoffset, I2C_DATA);
152 /* must have enough delay to allow BB bit to go low */
154 if (inw (I2C_STAT) & I2C_STAT_NACK) {
162 outw (I2C_CON_EN, I2C_CON);
163 while ((stat = inw (I2C_STAT)) || (inw (I2C_CON) & I2C_CON_MST)) {
165 /* have to read to clear intrrupt */
166 outw (0xFFFF, I2C_STAT);
170 outw (0xFFFF, I2C_STAT);
175 void flush_fifo(void)
178 /* note: if you try and read data when its not there or ready
179 * you get a bus error
182 stat = inw(I2C_STAT);
183 if(stat == I2C_STAT_RRDY){
185 outw(I2C_STAT_RRDY,I2C_STAT);
192 int i2c_probe (uchar chip)
194 int res = 1; /* default = fail */
196 if (chip == inw (I2C_OA)) {
200 /* wait until bus not busy */
203 /* try to read one byte */
205 /* set slave address */
207 /* stop bit needed here */
208 outw (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP, I2C_CON);
209 /* enough delay for the NACK bit set */
212 if (!(inw (I2C_STAT) & I2C_STAT_NACK)) {
213 res = 0; /* success case */
215 outw(0xFFFF, I2C_STAT);
217 outw(0xFFFF, I2C_STAT); /* failue, clear sources*/
218 outw (inw (I2C_CON) | I2C_CON_STP, I2C_CON); /* finish up xfer */
223 outw (0, I2C_CNT); /* don't allow any more data in...we don't want it.*/
224 outw(0xFFFF, I2C_STAT);
228 int i2c_read (uchar chip, uint addr, int alen, uchar * buffer, int len)
233 printf ("I2C read: addr len %d not supported\n", alen);
237 if (addr + len > 256) {
238 printf ("I2C read: address out of range\n");
242 for (i = 0; i < len; i++) {
243 if (i2c_read_byte (chip, addr + i, &buffer[i])) {
244 printf ("I2C read: I/O error\n");
245 i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE);
253 int i2c_write (uchar chip, uint addr, int alen, uchar * buffer, int len)
258 printf ("I2C read: addr len %d not supported\n", alen);
262 if (addr + len > 256) {
263 printf ("I2C read: address out of range\n");
267 for (i = 0; i < len; i++) {
268 if (i2c_write_byte (chip, addr + i, buffer[i])) {
269 printf ("I2C read: I/O error\n");
270 i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE);
278 static void wait_for_bb (void)
283 outw(0xFFFF, I2C_STAT); /* clear current interruts...*/
284 while ((stat = inw (I2C_STAT) & I2C_STAT_BB) && timeout--) {
285 outw (stat, I2C_STAT);
290 printf ("timed out in wait_for_bb: I2C_STAT=%x\n",
293 outw(0xFFFF, I2C_STAT); /* clear delayed stuff*/
296 static u16 wait_for_pin (void)
303 status = inw (I2C_STAT);
305 (I2C_STAT_ROVR | I2C_STAT_XUDF | I2C_STAT_XRDY |
306 I2C_STAT_RRDY | I2C_STAT_ARDY | I2C_STAT_NACK |
307 I2C_STAT_AL)) && timeout--);
310 printf ("timed out in wait_for_pin: I2C_STAT=%x\n",
312 outw(0xFFFF, I2C_STAT);
317 #endif /* CONFIG_DRIVER_OMAP24XX_I2C */