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 #if defined(CONFIG_AT91RM9200) || \
34 defined(CONFIG_AT91SAM9260) || defined(CONFIG_AT91SAM9261) || \
35 defined(CONFIG_AT91SAM9263)
37 #include <asm/arch/hardware.h>
38 #include <asm/arch/at91_pio.h>
39 #ifdef CONFIG_AT91_LEGACY
40 #include <asm/arch/gpio.h>
43 #ifdef CONFIG_IXP425 /* only valid for IXP425 */
44 #include <asm/arch/ixp425.h>
47 #include <asm/arch/hardware.h>
49 #if defined(CONFIG_MPC852T) || defined(CONFIG_MPC866)
54 #if defined(CONFIG_SOFT_I2C_GPIO_SCL)
55 # include <asm/gpio.h>
57 # ifndef I2C_GPIO_SYNC
58 # define I2C_GPIO_SYNC
64 gpio_request(CONFIG_SOFT_I2C_GPIO_SCL, "soft_i2c"); \
65 gpio_request(CONFIG_SOFT_I2C_GPIO_SDA, "soft_i2c"); \
70 # define I2C_ACTIVE do { } while (0)
74 # define I2C_TRISTATE do { } while (0)
78 # define I2C_READ gpio_get_value(CONFIG_SOFT_I2C_GPIO_SDA)
82 # define I2C_SDA(bit) \
85 gpio_direction_input(CONFIG_SOFT_I2C_GPIO_SDA); \
87 gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SDA, 0); \
93 # define I2C_SCL(bit) \
95 gpio_direction_output(CONFIG_SOFT_I2C_GPIO_SCL, bit); \
101 # define I2C_DELAY udelay(5) /* 1/4 I2C clock duration */
106 /* #define DEBUG_I2C */
109 DECLARE_GLOBAL_DATA_PTR;
112 /*-----------------------------------------------------------------------
118 #define I2C_ACK 0 /* PD_SDA level to ack a byte */
119 #define I2C_NOACK 1 /* PD_SDA level to noack a byte */
123 #define PRINTD(fmt,args...) do { \
124 if (gd->have_console) \
125 printf (fmt ,##args); \
128 #define PRINTD(fmt,args...)
131 #if defined(CONFIG_I2C_MULTI_BUS)
132 static unsigned int i2c_bus_num __attribute__ ((section (".data"))) = 0;
133 #endif /* CONFIG_I2C_MULTI_BUS */
135 /*-----------------------------------------------------------------------
138 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
139 static void send_reset (void);
141 static void send_start (void);
142 static void send_stop (void);
143 static void send_ack (int);
144 static int write_byte (uchar byte);
145 static uchar read_byte (int);
147 #if !defined(CONFIG_SYS_I2C_INIT_BOARD)
148 /*-----------------------------------------------------------------------
149 * Send a reset sequence consisting of 9 clocks with the data signal high
150 * to clock any confused device back into an idle state. Also send a
151 * <stop> at the end of the sequence for belts & suspenders.
153 static void send_reset(void)
155 I2C_SOFT_DECLARATIONS /* intentional without ';' */
164 for(j = 0; j < 9; j++) {
177 /*-----------------------------------------------------------------------
178 * START: High -> Low on SDA while SCL is High
180 static void send_start(void)
182 I2C_SOFT_DECLARATIONS /* intentional without ';' */
194 /*-----------------------------------------------------------------------
195 * STOP: Low -> High on SDA while SCL is High
197 static void send_stop(void)
199 I2C_SOFT_DECLARATIONS /* intentional without ';' */
213 /*-----------------------------------------------------------------------
214 * ack should be I2C_ACK or I2C_NOACK
216 static void send_ack(int ack)
218 I2C_SOFT_DECLARATIONS /* intentional without ';' */
232 /*-----------------------------------------------------------------------
233 * Send 8 bits and look for an acknowledgement.
235 static int write_byte(uchar data)
237 I2C_SOFT_DECLARATIONS /* intentional without ';' */
242 for(j = 0; j < 8; j++) {
245 I2C_SDA(data & 0x80);
255 * Look for an <ACK>(negative logic) and return it.
270 return(nack); /* not a nack is an ack */
273 #if defined(CONFIG_I2C_MULTI_BUS)
275 * Functions for multiple I2C bus handling
277 unsigned int i2c_get_bus_num(void)
282 int i2c_set_bus_num(unsigned int bus)
284 #if defined(CONFIG_I2C_MUX)
285 if (bus < CONFIG_SYS_MAX_I2C_BUS) {
290 ret = i2x_mux_select_mux(bus);
297 if (bus >= CONFIG_SYS_MAX_I2C_BUS)
305 /*-----------------------------------------------------------------------
306 * if ack == I2C_ACK, ACK the byte so can continue reading, else
307 * send I2C_NOACK to end the read.
309 static uchar read_byte(int ack)
311 I2C_SOFT_DECLARATIONS /* intentional without ';' */
316 * Read 8 bits, MSB first.
321 for(j = 0; j < 8; j++) {
335 /*=====================================================================*/
336 /* Public Functions */
337 /*=====================================================================*/
339 /*-----------------------------------------------------------------------
342 void i2c_init (int speed, int slaveaddr)
344 #if defined(CONFIG_SYS_I2C_INIT_BOARD)
345 /* call board specific i2c bus reset routine before accessing the */
346 /* environment, which might be in a chip on that bus. For details */
347 /* about this problem see doc/I2C_Edge_Conditions. */
351 * WARNING: Do NOT save speed in a static variable: if the
352 * I2C routines are called before RAM is initialized (to read
353 * the DIMM SPD, for instance), RAM won't be usable and your
360 /*-----------------------------------------------------------------------
361 * Probe to see if a chip is present. Also good for checking for the
362 * completion of EEPROM writes since the chip stops responding until
363 * the write completes (typically 10mSec).
365 int i2c_probe(uchar addr)
370 * perform 1 byte write transaction with just address byte
374 rc = write_byte ((addr << 1) | 0);
380 /*-----------------------------------------------------------------------
383 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
386 PRINTD("i2c_read: chip %02X addr %02X alen %d buffer %p len %d\n",
387 chip, addr, alen, buffer, len);
389 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
391 * EEPROM chips that implement "address overflow" are ones
392 * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
393 * address and the extra bits end up in the "chip address"
394 * bit slots. This makes a 24WC08 (1Kbyte) chip look like
395 * four 256 byte chips.
397 * Note that we consider the length of the address field to
398 * still be one byte because the extra address bits are
399 * hidden in the chip address.
401 chip |= ((addr >> (alen * 8)) & CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
403 PRINTD("i2c_read: fix addr_overflow: chip %02X addr %02X\n",
408 * Do the addressing portion of a write cycle to set the
409 * chip's address pointer. If the address length is zero,
410 * don't do the normal write cycle to set the address pointer,
411 * there is no address pointer in this chip.
415 if(write_byte(chip << 1)) { /* write cycle */
417 PRINTD("i2c_read, no chip responded %02X\n", chip);
420 shift = (alen-1) * 8;
422 if(write_byte(addr >> shift)) {
423 PRINTD("i2c_read, address not <ACK>ed\n");
429 /* Some I2C chips need a stop/start sequence here,
430 * other chips don't work with a full stop and need
431 * only a start. Default behaviour is to send the
432 * stop/start sequence.
434 #ifdef CONFIG_SOFT_I2C_READ_REPEATED_START
442 * Send the chip address again, this time for a read cycle.
443 * Then read the data. On the last byte, we do a NACK instead
444 * of an ACK(len == 0) to terminate the read.
446 write_byte((chip << 1) | 1); /* read cycle */
448 *buffer++ = read_byte(len == 0);
454 /*-----------------------------------------------------------------------
457 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
459 int shift, failures = 0;
461 PRINTD("i2c_write: chip %02X addr %02X alen %d buffer %p len %d\n",
462 chip, addr, alen, buffer, len);
465 if(write_byte(chip << 1)) { /* write cycle */
467 PRINTD("i2c_write, no chip responded %02X\n", chip);
470 shift = (alen-1) * 8;
472 if(write_byte(addr >> shift)) {
473 PRINTD("i2c_write, address not <ACK>ed\n");
480 if(write_byte(*buffer++)) {