3 * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
5 * (C) Copyright 2000 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
6 * Marius Groeger <mgroeger@sysgo.de>
8 * (C) Copyright 2003 Pengutronix e.K.
9 * Robert Schwebel <r.schwebel@pengutronix.de>
11 * See file CREDITS for list of people who contributed to this
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License as
16 * published by the Free Software Foundation; either version 2 of
17 * the License, or (at your option) any later version.
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 * GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, write to the Free Software
26 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
29 * Back ported to the 8xx platform (from the 8260 platform) by
30 * Murray.Jensen@cmst.csiro.au, 27-Jan-01.
33 /* FIXME: this file is PXA255 specific! What about other XScales? */
38 #ifdef CONFIG_HARD_I2C
41 * - CONFIG_SYS_I2C_SPEED
42 * - I2C_PXA_SLAVE_ADDR
45 #include <asm/arch/hardware.h>
46 #include <asm/arch/pxa-regs.h>
49 /*#define DEBUG_I2C 1 /###* activate local debugging output */
50 #define I2C_PXA_SLAVE_ADDR 0x1 /* slave pxa unit address */
52 #if (CONFIG_SYS_I2C_SPEED == 400000)
53 #define I2C_ICR_INIT (ICR_FM | ICR_BEIE | ICR_IRFIE | ICR_ITEIE | ICR_GCD | ICR_SCLE)
55 #define I2C_ICR_INIT (ICR_BEIE | ICR_IRFIE | ICR_ITEIE | ICR_GCD | ICR_SCLE)
58 #define I2C_ISR_INIT 0x7FF
61 #define PRINTD(x) printf x
67 /* Shall the current transfer have a start/stop condition? */
68 #define I2C_COND_NORMAL 0
69 #define I2C_COND_START 1
70 #define I2C_COND_STOP 2
72 /* Shall the current transfer be ack/nacked or being waited for it? */
73 #define I2C_ACKNAK_WAITACK 1
74 #define I2C_ACKNAK_SENDACK 2
75 #define I2C_ACKNAK_SENDNAK 4
77 /* Specify who shall transfer the data (master or slave) */
81 /* All transfers are described by this data structure */
91 * i2c_pxa_reset: - reset the host controller
95 static void i2c_reset( void )
97 writel(readl(ICR) & ~ICR_IUE, ICR); /* disable unit */
98 writel(readl(ICR) | ICR_UR, ICR); /* reset the unit */
100 writel(readl(ICR) & ~ICR_IUE, ICR); /* disable unit */
101 #ifdef CONFIG_CPU_MONAHANS
102 /* | CKENB_1_PWM1 | CKENB_0_PWM0); */
103 writel(readl(CKENB) | (CKENB_4_I2C), CKENB);
104 #else /* CONFIG_CPU_MONAHANS */
105 /* set the global I2C clock on */
106 writel(readl(CKEN) | CKEN14_I2C, CKEN);
108 writel(I2C_PXA_SLAVE_ADDR, ISAR); /* set our slave address */
109 writel(I2C_ICR_INIT, ICR); /* set control reg values */
110 writel(I2C_ISR_INIT, ISR); /* set clear interrupt bits */
111 writel(readl(ICR) | ICR_IUE, ICR); /* enable unit */
117 * i2c_isr_set_cleared: - wait until certain bits of the I2C status register
118 * are set and cleared
120 * @return: 1 in case of success, 0 means timeout (no match within 10 ms).
122 static int i2c_isr_set_cleared( unsigned long set_mask, unsigned long cleared_mask )
126 while( ((ISR & set_mask)!=set_mask) || ((ISR & cleared_mask)!=0) ){
128 if( timeout-- < 0 ) return 0;
136 * i2c_transfer: - Transfer one byte over the i2c bus
138 * This function can tranfer a byte over the i2c bus in both directions.
139 * It is used by the public API functions.
141 * @return: 0: transfer successful
142 * -1: message is empty
143 * -2: transmit timeout
145 * -4: receive timeout
146 * -5: illegal parameters
147 * -6: bus is busy and couldn't be aquired
149 int i2c_transfer(struct i2c_msg *msg)
154 goto transfer_error_msg_empty;
156 switch(msg->direction) {
160 /* check if bus is not busy */
161 if (!i2c_isr_set_cleared(0,ISR_IBB))
162 goto transfer_error_bus_busy;
164 /* start transmission */
165 writel(readl(ICR) & ~ICR_START, ICR);
166 writel(readl(ICR) & ~ICR_STOP, ICR);
167 writel(msg->data, IDBR);
168 if (msg->condition == I2C_COND_START)
169 writel(readl(ICR) | ICR_START, ICR);
170 if (msg->condition == I2C_COND_STOP)
171 writel(readl(ICR) | ICR_STOP, ICR);
172 if (msg->acknack == I2C_ACKNAK_SENDNAK)
173 writel(readl(ICR) | ICR_ACKNAK, ICR);
174 if (msg->acknack == I2C_ACKNAK_SENDACK)
175 writel(readl(ICR) & ~ICR_ACKNAK, ICR);
176 writel(readl(ICR) & ~ICR_ALDIE, ICR);
177 writel(readl(ICR) | ICR_TB, ICR);
179 /* transmit register empty? */
180 if (!i2c_isr_set_cleared(ISR_ITE,0))
181 goto transfer_error_transmit_timeout;
183 /* clear 'transmit empty' state */
184 writel(readl(ISR) | ISR_ITE, ISR);
186 /* wait for ACK from slave */
187 if (msg->acknack == I2C_ACKNAK_WAITACK)
188 if (!i2c_isr_set_cleared(0,ISR_ACKNAK))
189 goto transfer_error_ack_missing;
194 /* check if bus is not busy */
195 if (!i2c_isr_set_cleared(0,ISR_IBB))
196 goto transfer_error_bus_busy;
199 writel(readl(ICR) & ~ICR_START, ICR);
200 writel(readl(ICR) & ~ICR_STOP, ICR);
201 if (msg->condition == I2C_COND_START)
202 writel(readl(ICR) | ICR_START, ICR);
203 if (msg->condition == I2C_COND_STOP)
204 writel(readl(ICR) | ICR_STOP, ICR);
205 if (msg->acknack == I2C_ACKNAK_SENDNAK)
206 writel(readl(ICR) | ICR_ACKNAK, ICR);
207 if (msg->acknack == I2C_ACKNAK_SENDACK)
208 writel(readl(ICR) & ~ICR_ACKNAK, ICR);
209 writel(readl(ICR) & ~ICR_ALDIE, ICR);
210 writel(readl(ICR) | ICR_TB, ICR);
212 /* receive register full? */
213 if (!i2c_isr_set_cleared(ISR_IRF,0))
214 goto transfer_error_receive_timeout;
216 msg->data = readl(IDBR);
218 /* clear 'receive empty' state */
219 writel(readl(ISR) | ISR_IRF, ISR);
225 goto transfer_error_illegal_param;
231 transfer_error_msg_empty:
232 PRINTD(("i2c_transfer: error: 'msg' is empty\n"));
233 ret = -1; goto i2c_transfer_finish;
235 transfer_error_transmit_timeout:
236 PRINTD(("i2c_transfer: error: transmit timeout\n"));
237 ret = -2; goto i2c_transfer_finish;
239 transfer_error_ack_missing:
240 PRINTD(("i2c_transfer: error: ACK missing\n"));
241 ret = -3; goto i2c_transfer_finish;
243 transfer_error_receive_timeout:
244 PRINTD(("i2c_transfer: error: receive timeout\n"));
245 ret = -4; goto i2c_transfer_finish;
247 transfer_error_illegal_param:
248 PRINTD(("i2c_transfer: error: illegal parameters\n"));
249 ret = -5; goto i2c_transfer_finish;
251 transfer_error_bus_busy:
252 PRINTD(("i2c_transfer: error: bus is busy\n"));
253 ret = -6; goto i2c_transfer_finish;
256 PRINTD(("i2c_transfer: ISR: 0x%04x\n",ISR));
262 /* ------------------------------------------------------------------------ */
264 /* ------------------------------------------------------------------------ */
266 void i2c_init(int speed, int slaveaddr)
268 #ifdef CONFIG_SYS_I2C_INIT_BOARD
269 /* call board specific i2c bus reset routine before accessing the */
270 /* environment, which might be in a chip on that bus. For details */
271 /* about this problem see doc/I2C_Edge_Conditions. */
278 * i2c_probe: - Test if a chip answers for a given i2c address
280 * @chip: address of the chip which is searched for
281 * @return: 0 if a chip was found, -1 otherwhise
284 int i2c_probe(uchar chip)
290 msg.condition = I2C_COND_START;
291 msg.acknack = I2C_ACKNAK_WAITACK;
292 msg.direction = I2C_WRITE;
293 msg.data = (chip << 1) + 1;
294 if (i2c_transfer(&msg)) return -1;
296 msg.condition = I2C_COND_STOP;
297 msg.acknack = I2C_ACKNAK_SENDNAK;
298 msg.direction = I2C_READ;
300 if (i2c_transfer(&msg)) return -1;
307 * i2c_read: - Read multiple bytes from an i2c device
309 * The higher level routines take into account that this function is only
310 * called with len < page length of the device (see configuration file)
312 * @chip: address of the chip which is to be read
313 * @addr: i2c data address within the chip
314 * @alen: length of the i2c data address (1..2 bytes)
315 * @buffer: where to write the data
316 * @len: how much byte do we want to read
317 * @return: 0 in case of success
320 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
323 u8 addr_bytes[3]; /* lowest...highest byte of data address */
326 PRINTD(("i2c_read(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len));
330 /* dummy chip address write */
331 PRINTD(("i2c_read: dummy chip address write\n"));
332 msg.condition = I2C_COND_START;
333 msg.acknack = I2C_ACKNAK_WAITACK;
334 msg.direction = I2C_WRITE;
335 msg.data = (chip << 1);
337 if ((ret=i2c_transfer(&msg))) return -1;
340 * send memory address bytes;
341 * alen defines how much bytes we have to send.
343 /*addr &= ((1 << CONFIG_SYS_EEPROM_PAGE_WRITE_BITS)-1); */
344 addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF);
345 addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF);
346 addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
348 while (--alen >= 0) {
350 PRINTD(("i2c_read: send memory word address byte %1d\n",alen));
351 msg.condition = I2C_COND_NORMAL;
352 msg.acknack = I2C_ACKNAK_WAITACK;
353 msg.direction = I2C_WRITE;
354 msg.data = addr_bytes[alen];
355 if ((ret=i2c_transfer(&msg))) return -1;
359 /* start read sequence */
360 PRINTD(("i2c_read: start read sequence\n"));
361 msg.condition = I2C_COND_START;
362 msg.acknack = I2C_ACKNAK_WAITACK;
363 msg.direction = I2C_WRITE;
364 msg.data = (chip << 1);
366 if ((ret=i2c_transfer(&msg))) return -1;
368 /* read bytes; send NACK at last byte */
372 msg.condition = I2C_COND_STOP;
373 msg.acknack = I2C_ACKNAK_SENDNAK;
375 msg.condition = I2C_COND_NORMAL;
376 msg.acknack = I2C_ACKNAK_SENDACK;
379 msg.direction = I2C_READ;
381 if ((ret=i2c_transfer(&msg))) return -1;
384 PRINTD(("i2c_read: reading byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer));
396 * i2c_write: - Write multiple bytes to an i2c device
398 * The higher level routines take into account that this function is only
399 * called with len < page length of the device (see configuration file)
401 * @chip: address of the chip which is to be written
402 * @addr: i2c data address within the chip
403 * @alen: length of the i2c data address (1..2 bytes)
404 * @buffer: where to find the data to be written
405 * @len: how much byte do we want to read
406 * @return: 0 in case of success
409 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
412 u8 addr_bytes[3]; /* lowest...highest byte of data address */
414 PRINTD(("i2c_write(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len));
418 /* chip address write */
419 PRINTD(("i2c_write: chip address write\n"));
420 msg.condition = I2C_COND_START;
421 msg.acknack = I2C_ACKNAK_WAITACK;
422 msg.direction = I2C_WRITE;
423 msg.data = (chip << 1);
425 if (i2c_transfer(&msg)) return -1;
428 * send memory address bytes;
429 * alen defines how much bytes we have to send.
431 addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF);
432 addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF);
433 addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
435 while (--alen >= 0) {
437 PRINTD(("i2c_write: send memory word address\n"));
438 msg.condition = I2C_COND_NORMAL;
439 msg.acknack = I2C_ACKNAK_WAITACK;
440 msg.direction = I2C_WRITE;
441 msg.data = addr_bytes[alen];
442 if (i2c_transfer(&msg)) return -1;
445 /* write bytes; send NACK at last byte */
448 PRINTD(("i2c_write: writing byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer));
451 msg.condition = I2C_COND_STOP;
453 msg.condition = I2C_COND_NORMAL;
455 msg.acknack = I2C_ACKNAK_WAITACK;
456 msg.direction = I2C_WRITE;
457 msg.data = *(buffer++);
459 if (i2c_transfer(&msg)) return -1;
469 #endif /* CONFIG_HARD_I2C */