2 * (C) Copyright 2001, 2002
3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5 * See file CREDITS for list of people who contributed to this
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.
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.
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,
23 * This has been changed substantially by Gerald Van Baren, Custom IDEAS,
24 * vanbaren@cideas.com. It was heavily influenced by LiMon, written by
29 #ifdef CONFIG_MPC8260 /* only valid for MPC8260 */
33 #ifdef CONFIG_AT91RM9200 /* need this for the at91rm9200 */
35 #include <asm/arch/hardware.h>
37 #ifdef CONFIG_AT91SAM9263 /* only valid for AT91SAM9263 */
38 #include <asm/arch/at91_pmc.h>
39 #include <asm/arch/gpio.h>
40 #include <asm/arch/io.h>
42 #ifdef CONFIG_IXP425 /* only valid for IXP425 */
43 #include <asm/arch/ixp425.h>
46 #include <asm/arch/hardware.h>
48 #if defined(CONFIG_MPC852T) || defined(CONFIG_MPC866)
53 /* #define DEBUG_I2C */
56 DECLARE_GLOBAL_DATA_PTR;
59 /*-----------------------------------------------------------------------
65 #define I2C_ACK 0 /* PD_SDA level to ack a byte */
66 #define I2C_NOACK 1 /* PD_SDA level to noack a byte */
70 #define PRINTD(fmt,args...) do { \
71 if (gd->have_console) \
72 printf (fmt ,##args); \
75 #define PRINTD(fmt,args...)
78 #if defined(CONFIG_I2C_MULTI_BUS)
79 static unsigned int i2c_bus_num __attribute__ ((section (".data"))) = 0;
80 #endif /* CONFIG_I2C_MULTI_BUS */
82 /*-----------------------------------------------------------------------
85 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
86 static void send_reset (void);
88 static void send_start (void);
89 static void send_stop (void);
90 static void send_ack (int);
91 static int write_byte (uchar byte);
92 static uchar read_byte (int);
94 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
95 /*-----------------------------------------------------------------------
96 * Send a reset sequence consisting of 9 clocks with the data signal high
97 * to clock any confused device back into an idle state. Also send a
98 * <stop> at the end of the sequence for belts & suspenders.
100 static void send_reset(void)
102 I2C_SOFT_DECLARATIONS /* intentional without ';' */
111 for(j = 0; j < 9; j++) {
124 /*-----------------------------------------------------------------------
125 * START: High -> Low on SDA while SCL is High
127 static void send_start(void)
129 I2C_SOFT_DECLARATIONS /* intentional without ';' */
141 /*-----------------------------------------------------------------------
142 * STOP: Low -> High on SDA while SCL is High
144 static void send_stop(void)
146 I2C_SOFT_DECLARATIONS /* intentional without ';' */
160 /*-----------------------------------------------------------------------
161 * ack should be I2C_ACK or I2C_NOACK
163 static void send_ack(int ack)
165 I2C_SOFT_DECLARATIONS /* intentional without ';' */
179 /*-----------------------------------------------------------------------
180 * Send 8 bits and look for an acknowledgement.
182 static int write_byte(uchar data)
184 I2C_SOFT_DECLARATIONS /* intentional without ';' */
189 for(j = 0; j < 8; j++) {
192 I2C_SDA(data & 0x80);
202 * Look for an <ACK>(negative logic) and return it.
217 return(nack); /* not a nack is an ack */
220 #if defined(CONFIG_I2C_MULTI_BUS)
222 * Functions for multiple I2C bus handling
224 unsigned int i2c_get_bus_num(void)
229 int i2c_set_bus_num(unsigned int bus)
231 #if defined(CONFIG_I2C_MUX)
232 if (bus < CONFIG_SYS_MAX_I2C_BUS) {
237 ret = i2x_mux_select_mux(bus);
244 if (bus >= CONFIG_SYS_MAX_I2C_BUS)
252 /*-----------------------------------------------------------------------
253 * if ack == I2C_ACK, ACK the byte so can continue reading, else
254 * send I2C_NOACK to end the read.
256 static uchar read_byte(int ack)
258 I2C_SOFT_DECLARATIONS /* intentional without ';' */
263 * Read 8 bits, MSB first.
268 for(j = 0; j < 8; j++) {
282 /*=====================================================================*/
283 /* Public Functions */
284 /*=====================================================================*/
286 /*-----------------------------------------------------------------------
289 void i2c_init (int speed, int slaveaddr)
291 #if defined(CONFIG_SYS_I2C_INIT_BOARD)
292 /* call board specific i2c bus reset routine before accessing the */
293 /* environment, which might be in a chip on that bus. For details */
294 /* about this problem see doc/I2C_Edge_Conditions. */
298 * WARNING: Do NOT save speed in a static variable: if the
299 * I2C routines are called before RAM is initialized (to read
300 * the DIMM SPD, for instance), RAM won't be usable and your
307 /*-----------------------------------------------------------------------
308 * Probe to see if a chip is present. Also good for checking for the
309 * completion of EEPROM writes since the chip stops responding until
310 * the write completes (typically 10mSec).
312 int i2c_probe(uchar addr)
317 * perform 1 byte write transaction with just address byte
321 rc = write_byte ((addr << 1) | 0);
327 /*-----------------------------------------------------------------------
330 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
333 PRINTD("i2c_read: chip %02X addr %02X alen %d buffer %p len %d\n",
334 chip, addr, alen, buffer, len);
336 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
338 * EEPROM chips that implement "address overflow" are ones
339 * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
340 * address and the extra bits end up in the "chip address"
341 * bit slots. This makes a 24WC08 (1Kbyte) chip look like
342 * four 256 byte chips.
344 * Note that we consider the length of the address field to
345 * still be one byte because the extra address bits are
346 * hidden in the chip address.
348 chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
350 PRINTD("i2c_read: fix addr_overflow: chip %02X addr %02X\n",
355 * Do the addressing portion of a write cycle to set the
356 * chip's address pointer. If the address length is zero,
357 * don't do the normal write cycle to set the address pointer,
358 * there is no address pointer in this chip.
362 if(write_byte(chip << 1)) { /* write cycle */
364 PRINTD("i2c_read, no chip responded %02X\n", chip);
367 shift = (alen-1) * 8;
369 if(write_byte(addr >> shift)) {
370 PRINTD("i2c_read, address not <ACK>ed\n");
376 /* Some I2C chips need a stop/start sequence here,
377 * other chips don't work with a full stop and need
378 * only a start. Default behaviour is to send the
379 * stop/start sequence.
381 #ifdef CONFIG_SOFT_I2C_READ_REPEATED_START
389 * Send the chip address again, this time for a read cycle.
390 * Then read the data. On the last byte, we do a NACK instead
391 * of an ACK(len == 0) to terminate the read.
393 write_byte((chip << 1) | 1); /* read cycle */
395 *buffer++ = read_byte(len == 0);
401 /*-----------------------------------------------------------------------
404 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
406 int shift, failures = 0;
408 PRINTD("i2c_write: chip %02X addr %02X alen %d buffer %p len %d\n",
409 chip, addr, alen, buffer, len);
412 if(write_byte(chip << 1)) { /* write cycle */
414 PRINTD("i2c_write, no chip responded %02X\n", chip);
417 shift = (alen-1) * 8;
419 if(write_byte(addr >> shift)) {
420 PRINTD("i2c_write, address not <ACK>ed\n");
427 if(write_byte(*buffer++)) {