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wdenk2cbe5712004-10-10 17:05:18 +00001/*
2 * i2c Support for Atmel's AT91RM9200 Two-Wire Interface
3 *
4 * (c) Rick Bronson
5 *
6 * Borrowed heavily from original work by:
7 * Copyright (c) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
8 *
9 * Modified to work with u-boot by (C) 2004 Gary Jennejohn garyj@denx.de
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 *
25*/
26#include <common.h>
27
28#ifdef CONFIG_HARD_I2C
29
30#include <i2c.h>
31#include <asm/io.h>
32#include <asm/arch/hardware.h>
33
34#include <at91rm9200_i2c.h>
35
wdenk45ea3fc2004-12-14 23:28:24 +000036/* define DEBUG */
wdenk2cbe5712004-10-10 17:05:18 +000037
38/*
39 * Poll the i2c status register until the specified bit is set.
40 * Returns 0 if timed out (100 msec)
41 */
42static short at91_poll_status(AT91PS_TWI twi, unsigned long bit) {
43 int loop_cntr = 10000;
44 do {
wdenk9d5028c2004-11-21 00:06:33 +000045 udelay(10);
wdenk2cbe5712004-10-10 17:05:18 +000046 } while (!(twi->TWI_SR & bit) && (--loop_cntr > 0));
47
48 return (loop_cntr > 0);
49}
50
51/*
52 * Generic i2c master transfer entrypoint
53 *
54 * rw == 1 means that this is a read
55 */
56static int
57at91_xfer(unsigned char chip, unsigned int addr, int alen,
58 unsigned char *buffer, int len, int rw)
59{
60 AT91PS_TWI twi = (AT91PS_TWI) AT91_TWI_BASE;
61 int length;
62 unsigned char *buf;
wdenk2cbe5712004-10-10 17:05:18 +000063 /* Set the TWI Master Mode Register */
64 twi->TWI_MMR = (chip << 16) | (alen << 8)
65 | ((rw == 1) ? AT91C_TWI_MREAD : 0);
66
67 /* Set TWI Internal Address Register with first messages data field */
wdenk2cbe5712004-10-10 17:05:18 +000068 if (alen > 0)
Wolfgang Denk78da6072005-10-06 01:22:22 +020069 twi->TWI_IADR = addr;
wdenk2cbe5712004-10-10 17:05:18 +000070
71 length = len;
72 buf = buffer;
73 if (length && buf) { /* sanity check */
74 if (rw) {
75 twi->TWI_CR = AT91C_TWI_START;
76 while (length--) {
77 if (!length)
78 twi->TWI_CR = AT91C_TWI_STOP;
79 /* Wait until transfer is finished */
80 if (!at91_poll_status(twi, AT91C_TWI_RXRDY)) {
wdenk45ea3fc2004-12-14 23:28:24 +000081 debug ("at91_i2c: timeout 1\n");
wdenk2cbe5712004-10-10 17:05:18 +000082 return 1;
83 }
84 *buf++ = twi->TWI_RHR;
85 }
86 if (!at91_poll_status(twi, AT91C_TWI_TXCOMP)) {
wdenk45ea3fc2004-12-14 23:28:24 +000087 debug ("at91_i2c: timeout 2\n");
wdenk2cbe5712004-10-10 17:05:18 +000088 return 1;
89 }
90 } else {
91 twi->TWI_CR = AT91C_TWI_START;
92 while (length--) {
93 twi->TWI_THR = *buf++;
94 if (!length)
95 twi->TWI_CR = AT91C_TWI_STOP;
96 if (!at91_poll_status(twi, AT91C_TWI_TXRDY)) {
wdenk45ea3fc2004-12-14 23:28:24 +000097 debug ("at91_i2c: timeout 3\n");
wdenk2cbe5712004-10-10 17:05:18 +000098 return 1;
99 }
100 }
101 /* Wait until transfer is finished */
102 if (!at91_poll_status(twi, AT91C_TWI_TXCOMP)) {
wdenk45ea3fc2004-12-14 23:28:24 +0000103 debug ("at91_i2c: timeout 4\n");
wdenk2cbe5712004-10-10 17:05:18 +0000104 return 1;
105 }
106 }
107 }
108 return 0;
109}
110
111int
112i2c_probe(unsigned char chip)
113{
Wolfgang Denkd52fb7e2006-03-11 22:53:33 +0100114 unsigned char buffer[1];
wdenk2cbe5712004-10-10 17:05:18 +0000115
116 return at91_xfer(chip, 0, 0, buffer, 1, 1);
117}
118
119int
wdenk59acc292005-04-03 14:18:51 +0000120i2c_read (unsigned char chip, unsigned int addr, int alen,
121 unsigned char *buffer, int len)
wdenk2cbe5712004-10-10 17:05:18 +0000122{
wdenkb6508512004-10-10 18:03:33 +0000123#ifdef CFG_I2C_EEPROM_ADDR_OVERFLOW
wdenk2cbe5712004-10-10 17:05:18 +0000124 /* we only allow one address byte */
125 if (alen > 1)
126 return 1;
wdenk2cbe5712004-10-10 17:05:18 +0000127 /* XXX assume an ATMEL AT24C16 */
128 if (alen == 1) {
wdenkb6508512004-10-10 18:03:33 +0000129#if 0 /* EEPROM code already sets this correctly */
wdenk2cbe5712004-10-10 17:05:18 +0000130 chip |= (addr >> 8) & 0xff;
wdenkb6508512004-10-10 18:03:33 +0000131#endif
wdenk2cbe5712004-10-10 17:05:18 +0000132 addr = addr & 0xff;
133 }
134#endif
135 return at91_xfer(chip, addr, alen, buffer, len, 1);
136}
137
138int
139i2c_write(unsigned char chip, unsigned int addr, int alen,
wdenk2a8af182005-04-13 10:02:42 +0000140 unsigned char *buffer, int len)
wdenk2cbe5712004-10-10 17:05:18 +0000141{
wdenk2a8af182005-04-13 10:02:42 +0000142#ifdef CFG_I2C_EEPROM_ADDR_OVERFLOW
wdenk2cbe5712004-10-10 17:05:18 +0000143 int i;
144 unsigned char *buf;
145
146 /* we only allow one address byte */
147 if (alen > 1)
148 return 1;
wdenk2cbe5712004-10-10 17:05:18 +0000149 /* XXX assume an ATMEL AT24C16 */
150 if (alen == 1) {
151 buf = buffer;
152 /* do single byte writes */
153 for (i = 0; i < len; i++) {
wdenkb6508512004-10-10 18:03:33 +0000154#if 0 /* EEPROM code already sets this correctly */
wdenk2cbe5712004-10-10 17:05:18 +0000155 chip |= (addr >> 8) & 0xff;
wdenkb6508512004-10-10 18:03:33 +0000156#endif
wdenk2cbe5712004-10-10 17:05:18 +0000157 addr = addr & 0xff;
158 if (at91_xfer(chip, addr, alen, buf++, 1, 0))
159 return 1;
wdenkb6508512004-10-10 18:03:33 +0000160 addr++;
wdenk2cbe5712004-10-10 17:05:18 +0000161 }
wdenkb6508512004-10-10 18:03:33 +0000162 return 0;
wdenk2cbe5712004-10-10 17:05:18 +0000163 }
wdenk2cbe5712004-10-10 17:05:18 +0000164#endif
165 return at91_xfer(chip, addr, alen, buffer, len, 0);
166}
167
168/*
169 * Main initialization routine
170 */
171void
172i2c_init(int speed, int slaveaddr)
173{
174 AT91PS_TWI twi = (AT91PS_TWI) AT91_TWI_BASE;
175
176 *AT91C_PIOA_PDR = AT91C_PA25_TWD | AT91C_PA26_TWCK;
177 *AT91C_PIOA_ASR = AT91C_PA25_TWD | AT91C_PA26_TWCK;
178 *AT91C_PIOA_MDER = AT91C_PA25_TWD | AT91C_PA26_TWCK;
179 *AT91C_PMC_PCER = 1 << AT91C_ID_TWI; /* enable peripheral clock */
180
181 twi->TWI_IDR = 0x3ff; /* Disable all interrupts */
182 twi->TWI_CR = AT91C_TWI_SWRST; /* Reset peripheral */
183 twi->TWI_CR = AT91C_TWI_MSEN | AT91C_TWI_SVDIS; /* Set Master mode */
184
185 /* Here, CKDIV = 1 and CHDIV=CLDIV ==> CLDIV = CHDIV = 1/4*((Fmclk/FTWI) -6) */
186 twi->TWI_CWGR = AT91C_TWI_CKDIV1 | AT91C_TWI_CLDIV3 | (AT91C_TWI_CLDIV3 << 8);
187
wdenk45ea3fc2004-12-14 23:28:24 +0000188 debug ("Found AT91 i2c\n");
wdenk2cbe5712004-10-10 17:05:18 +0000189 return;
190}
wdenkb77fad32005-04-07 22:36:40 +0000191
192uchar i2c_reg_read(uchar i2c_addr, uchar reg)
193{
Wolfgang Denkd52fb7e2006-03-11 22:53:33 +0100194 unsigned char buf;
wdenkb77fad32005-04-07 22:36:40 +0000195
196 i2c_read(i2c_addr, reg, 1, &buf, 1);
197
198 return(buf);
199}
200
201void i2c_reg_write(uchar i2c_addr, uchar reg, uchar val)
202{
203 i2c_write(i2c_addr, reg, 1, &val, 1);
204}
205
wdenk2cbe5712004-10-10 17:05:18 +0000206#endif /* CONFIG_HARD_I2C */