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? */
37 #ifdef CONFIG_HARD_I2C
41 * - I2C_PXA_SLAVE_ADDR
44 #include <asm/arch/hardware.h>
45 #include <asm/arch/pxa-regs.h>
48 /*#define DEBUG_I2C 1 /###* activate local debugging output */
49 #define I2C_PXA_SLAVE_ADDR 0x1 /* slave pxa unit address */
50 #define I2C_ICR_INIT (ICR_BEIE | ICR_IRFIE | ICR_ITEIE | ICR_GCD | ICR_SCLE)
51 #define I2C_ISR_INIT 0x7FF
54 #define PRINTD(x) printf x
60 /* Shall the current transfer have a start/stop condition? */
61 #define I2C_COND_NORMAL 0
62 #define I2C_COND_START 1
63 #define I2C_COND_STOP 2
65 /* Shall the current transfer be ack/nacked or being waited for it? */
66 #define I2C_ACKNAK_WAITACK 1
67 #define I2C_ACKNAK_SENDACK 2
68 #define I2C_ACKNAK_SENDNAK 4
70 /* Specify who shall transfer the data (master or slave) */
74 /* All transfers are described by this data structure */
84 * i2c_pxa_reset: - reset the host controller
88 static void i2c_reset( void )
90 ICR &= ~ICR_IUE; /* disable unit */
91 ICR |= ICR_UR; /* reset the unit */
93 ICR &= ~ICR_IUE; /* disable unit */
94 CKEN |= CKEN14_I2C; /* set the global I2C clock on */
95 ISAR = I2C_PXA_SLAVE_ADDR; /* set our slave address */
96 ICR = I2C_ICR_INIT; /* set control register values */
97 ISR = I2C_ISR_INIT; /* set clear interrupt bits */
98 ICR |= ICR_IUE; /* enable unit */
104 * i2c_isr_set_cleared: - wait until certain bits of the I2C status register
105 * are set and cleared
107 * @return: 0 in case of success, 1 means timeout (no match within 10 ms).
110 static int i2c_isr_set_cleared( unsigned long set_mask, unsigned long cleared_mask )
114 while( ((ISR & set_mask)!=set_mask) || ((ISR & cleared_mask)!=0) ){
116 if( timeout-- < 0 ) return 0;
124 * i2c_transfer: - Transfer one byte over the i2c bus
126 * This function can tranfer a byte over the i2c bus in both directions.
127 * It is used by the public API functions.
129 * @return: 0: transfer successful
130 * -1: message is empty
131 * -2: transmit timeout
133 * -4: receive timeout
134 * -5: illegal parameters
135 * -6: bus is busy and couldn't be aquired
137 int i2c_transfer(struct i2c_msg *msg)
142 goto transfer_error_msg_empty;
144 switch(msg->direction) {
148 /* check if bus is not busy */
149 if (!i2c_isr_set_cleared(0,ISR_IBB))
150 goto transfer_error_bus_busy;
152 /* start transmission */
156 if (msg->condition == I2C_COND_START) ICR |= ICR_START;
157 if (msg->condition == I2C_COND_STOP) ICR |= ICR_STOP;
158 if (msg->acknack == I2C_ACKNAK_SENDNAK) ICR |= ICR_ACKNAK;
159 if (msg->acknack == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK;
163 /* transmit register empty? */
164 if (!i2c_isr_set_cleared(ISR_ITE,0))
165 goto transfer_error_transmit_timeout;
167 /* clear 'transmit empty' state */
170 /* wait for ACK from slave */
171 if (msg->acknack == I2C_ACKNAK_WAITACK)
172 if (!i2c_isr_set_cleared(0,ISR_ACKNAK))
173 goto transfer_error_ack_missing;
178 /* check if bus is not busy */
179 if (!i2c_isr_set_cleared(0,ISR_IBB))
180 goto transfer_error_bus_busy;
185 if (msg->condition == I2C_COND_START) ICR |= ICR_START;
186 if (msg->condition == I2C_COND_STOP) ICR |= ICR_STOP;
187 if (msg->acknack == I2C_ACKNAK_SENDNAK) ICR |= ICR_ACKNAK;
188 if (msg->acknack == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK;
192 /* receive register full? */
193 if (!i2c_isr_set_cleared(ISR_IRF,0))
194 goto transfer_error_receive_timeout;
198 /* clear 'receive empty' state */
205 goto transfer_error_illegal_param;
211 transfer_error_msg_empty:
212 PRINTD(("i2c_transfer: error: 'msg' is empty\n"));
213 ret = -1; goto i2c_transfer_finish;
215 transfer_error_transmit_timeout:
216 PRINTD(("i2c_transfer: error: transmit timeout\n"));
217 ret = -2; goto i2c_transfer_finish;
219 transfer_error_ack_missing:
220 PRINTD(("i2c_transfer: error: ACK missing\n"));
221 ret = -3; goto i2c_transfer_finish;
223 transfer_error_receive_timeout:
224 PRINTD(("i2c_transfer: error: receive timeout\n"));
225 ret = -4; goto i2c_transfer_finish;
227 transfer_error_illegal_param:
228 PRINTD(("i2c_transfer: error: illegal parameters\n"));
229 ret = -5; goto i2c_transfer_finish;
231 transfer_error_bus_busy:
232 PRINTD(("i2c_transfer: error: bus is busy\n"));
233 ret = -6; goto i2c_transfer_finish;
236 PRINTD(("i2c_transfer: ISR: 0x%04x\n",ISR));
242 /* ------------------------------------------------------------------------ */
244 /* ------------------------------------------------------------------------ */
246 void i2c_init(int speed, int slaveaddr)
248 #ifdef CFG_I2C_INIT_BOARD
249 /* call board specific i2c bus reset routine before accessing the */
250 /* environment, which might be in a chip on that bus. For details */
251 /* about this problem see doc/I2C_Edge_Conditions. */
258 * i2c_probe: - Test if a chip answers for a given i2c address
260 * @chip: address of the chip which is searched for
261 * @return: 0 if a chip was found, -1 otherwhise
264 int i2c_probe(uchar chip)
270 msg.condition = I2C_COND_START;
271 msg.acknack = I2C_ACKNAK_WAITACK;
272 msg.direction = I2C_WRITE;
273 msg.data = (chip << 1) + 1;
274 if (i2c_transfer(&msg)) return -1;
276 msg.condition = I2C_COND_STOP;
277 msg.acknack = I2C_ACKNAK_SENDNAK;
278 msg.direction = I2C_READ;
280 if (i2c_transfer(&msg)) return -1;
287 * i2c_read: - Read multiple bytes from an i2c device
289 * The higher level routines take into account that this function is only
290 * called with len < page length of the device (see configuration file)
292 * @chip: address of the chip which is to be read
293 * @addr: i2c data address within the chip
294 * @alen: length of the i2c data address (1..2 bytes)
295 * @buffer: where to write the data
296 * @len: how much byte do we want to read
297 * @return: 0 in case of success
300 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
303 u8 addr_bytes[3]; /* lowest...highest byte of data address */
306 PRINTD(("i2c_read(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len));
310 /* dummy chip address write */
311 PRINTD(("i2c_read: dummy chip address write\n"));
312 msg.condition = I2C_COND_START;
313 msg.acknack = I2C_ACKNAK_WAITACK;
314 msg.direction = I2C_WRITE;
315 msg.data = (chip << 1);
317 if ((ret=i2c_transfer(&msg))) return -1;
320 * send memory address bytes;
321 * alen defines how much bytes we have to send.
323 /*addr &= ((1 << CFG_EEPROM_PAGE_WRITE_BITS)-1); */
324 addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF);
325 addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF);
326 addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
328 while (--alen >= 0) {
330 PRINTD(("i2c_read: send memory word address byte %1d\n",alen));
331 msg.condition = I2C_COND_NORMAL;
332 msg.acknack = I2C_ACKNAK_WAITACK;
333 msg.direction = I2C_WRITE;
334 msg.data = addr_bytes[alen];
335 if ((ret=i2c_transfer(&msg))) return -1;
339 /* start read sequence */
340 PRINTD(("i2c_read: start read sequence\n"));
341 msg.condition = I2C_COND_START;
342 msg.acknack = I2C_ACKNAK_WAITACK;
343 msg.direction = I2C_WRITE;
344 msg.data = (chip << 1);
346 if ((ret=i2c_transfer(&msg))) return -1;
348 /* read bytes; send NACK at last byte */
352 msg.condition = I2C_COND_STOP;
353 msg.acknack = I2C_ACKNAK_SENDNAK;
355 msg.condition = I2C_COND_NORMAL;
356 msg.acknack = I2C_ACKNAK_SENDACK;
359 msg.direction = I2C_READ;
361 if ((ret=i2c_transfer(&msg))) return -1;
363 *(buffer++) = msg.data;
365 PRINTD(("i2c_read: reading byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer));
376 * i2c_write: - Write multiple bytes to an i2c device
378 * The higher level routines take into account that this function is only
379 * called with len < page length of the device (see configuration file)
381 * @chip: address of the chip which is to be written
382 * @addr: i2c data address within the chip
383 * @alen: length of the i2c data address (1..2 bytes)
384 * @buffer: where to find the data to be written
385 * @len: how much byte do we want to read
386 * @return: 0 in case of success
389 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
392 u8 addr_bytes[3]; /* lowest...highest byte of data address */
394 PRINTD(("i2c_write(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len));
398 /* chip address write */
399 PRINTD(("i2c_write: chip address write\n"));
400 msg.condition = I2C_COND_START;
401 msg.acknack = I2C_ACKNAK_WAITACK;
402 msg.direction = I2C_WRITE;
403 msg.data = (chip << 1);
405 if (i2c_transfer(&msg)) return -1;
408 * send memory address bytes;
409 * alen defines how much bytes we have to send.
411 addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF);
412 addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF);
413 addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
415 while (--alen >= 0) {
417 PRINTD(("i2c_write: send memory word address\n"));
418 msg.condition = I2C_COND_NORMAL;
419 msg.acknack = I2C_ACKNAK_WAITACK;
420 msg.direction = I2C_WRITE;
421 msg.data = addr_bytes[alen];
422 if (i2c_transfer(&msg)) return -1;
425 /* write bytes; send NACK at last byte */
428 PRINTD(("i2c_write: writing byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer));
431 msg.condition = I2C_COND_STOP;
433 msg.condition = I2C_COND_NORMAL;
435 msg.acknack = I2C_ACKNAK_WAITACK;
436 msg.direction = I2C_WRITE;
437 msg.data = *(buffer++);
439 if (i2c_transfer(&msg)) return -1;
449 uchar i2c_reg_read (uchar chip, uchar reg)
451 PRINTD(("i2c_reg_read(chip=0x%02x, reg=0x%02x)\n",chip,reg));
455 void i2c_reg_write(uchar chip, uchar reg, uchar val)
457 PRINTD(("i2c_reg_write(chip=0x%02x, reg=0x%02x, val=0x%02x)\n",chip,reg,val));
460 #endif /* CONFIG_HARD_I2C */