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wdenk43d96162003-03-06 00:02:04 +00001/*
2 * (C) Copyright 2000
3 * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
4 *
5 * (C) Copyright 2000 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
6 * Marius Groeger <mgroeger@sysgo.de>
7 *
8 * (C) Copyright 2003 Pengutronix e.K.
9 * Robert Schwebel <r.schwebel@pengutronix.de>
10 *
11 * See file CREDITS for list of people who contributed to this
12 * project.
13 *
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.
18 *
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.
23 *
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,
27 * MA 02111-1307 USA
28 *
29 * Back ported to the 8xx platform (from the 8260 platform) by
30 * Murray.Jensen@cmst.csiro.au, 27-Jan-01.
31 */
32
33/* FIXME: this file is PXA255 specific! What about other XScales? */
34
35#include <common.h>
36
37#ifdef CONFIG_HARD_I2C
38
39/*
40 * - CFG_I2C_SPEED
41 * - I2C_PXA_SLAVE_ADDR
42 */
43
wdenk47cd00f2003-03-06 13:39:27 +000044#include <asm/arch/hardware.h>
wdenk43d96162003-03-06 00:02:04 +000045#include <asm/arch/pxa-regs.h>
46#include <i2c.h>
47
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
52
53#ifdef DEBUG_I2C
54#define PRINTD(x) printf x
55#else
56#define PRINTD(x)
57#endif
58
59
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
64
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
69
70/* Specify who shall transfer the data (master or slave) */
71#define I2C_READ 0
72#define I2C_WRITE 1
73
74/* All transfers are described by this data structure */
75struct i2c_msg {
76 u8 condition;
77 u8 acknack;
78 u8 direction;
79 u8 data;
80};
81
82
83/**
84 * i2c_pxa_reset: - reset the host controller
85 *
86 */
87
88static void i2c_reset( void )
89{
90 ICR &= ~ICR_IUE; /* disable unit */
91 ICR |= ICR_UR; /* reset the unit */
92 udelay(100);
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 */
99 udelay(100);
100}
101
102
103/**
104 * i2c_isr_set_cleared: - wait until certain bits of the I2C status register
105 * are set and cleared
106 *
107 * @return: 0 in case of success, 1 means timeout (no match within 10 ms).
108 */
109
110static int i2c_isr_set_cleared( unsigned long set_mask, unsigned long cleared_mask )
111{
112 int timeout = 10000;
113
114 while( ((ISR & set_mask)!=set_mask) || ((ISR & cleared_mask)!=0) ){
115 udelay( 10 );
116 if( timeout-- < 0 ) return 0;
117 }
118
119 return 1;
120}
121
122
123/**
124 * i2c_transfer: - Transfer one byte over the i2c bus
125 *
126 * This function can tranfer a byte over the i2c bus in both directions.
127 * It is used by the public API functions.
128 *
129 * @return: 0: transfer successful
130 * -1: message is empty
131 * -2: transmit timeout
132 * -3: ACK missing
133 * -4: receive timeout
134 * -5: illegal parameters
135 * -6: bus is busy and couldn't be aquired
136 */
137int i2c_transfer(struct i2c_msg *msg)
138{
139 int ret;
140
141 if (!msg)
142 goto transfer_error_msg_empty;
143
144 switch(msg->direction) {
145
146 case I2C_WRITE:
147
148 /* check if bus is not busy */
149 if (!i2c_isr_set_cleared(0,ISR_IBB))
150 goto transfer_error_bus_busy;
151
152 /* start transmission */
153 ICR &= ~ICR_START;
154 ICR &= ~ICR_STOP;
155 IDBR = msg->data;
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;
160 ICR &= ~ICR_ALDIE;
161 ICR |= ICR_TB;
162
163 /* transmit register empty? */
164 if (!i2c_isr_set_cleared(ISR_ITE,0))
165 goto transfer_error_transmit_timeout;
166
167 /* clear 'transmit empty' state */
168 ISR |= ISR_ITE;
169
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;
174 break;
175
176 case I2C_READ:
177
178 /* check if bus is not busy */
179 if (!i2c_isr_set_cleared(0,ISR_IBB))
180 goto transfer_error_bus_busy;
181
182 /* start receive */
183 ICR &= ~ICR_START;
184 ICR &= ~ICR_STOP;
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;
189 ICR &= ~ICR_ALDIE;
190 ICR |= ICR_TB;
191
192 /* receive register full? */
193 if (!i2c_isr_set_cleared(ISR_IRF,0))
194 goto transfer_error_receive_timeout;
195
196 msg->data = IDBR;
197
198 /* clear 'receive empty' state */
199 ISR |= ISR_IRF;
200
201 break;
202
203 default:
204
205 goto transfer_error_illegal_param;
206
207 }
208
209 return 0;
210
211transfer_error_msg_empty:
212 PRINTD(("i2c_transfer: error: 'msg' is empty\n"));
213 ret = -1; goto i2c_transfer_finish;
214
215transfer_error_transmit_timeout:
216 PRINTD(("i2c_transfer: error: transmit timeout\n"));
217 ret = -2; goto i2c_transfer_finish;
218
219transfer_error_ack_missing:
220 PRINTD(("i2c_transfer: error: ACK missing\n"));
221 ret = -3; goto i2c_transfer_finish;
222
223transfer_error_receive_timeout:
224 PRINTD(("i2c_transfer: error: receive timeout\n"));
225 ret = -4; goto i2c_transfer_finish;
226
227transfer_error_illegal_param:
228 PRINTD(("i2c_transfer: error: illegal parameters\n"));
229 ret = -5; goto i2c_transfer_finish;
230
231transfer_error_bus_busy:
232 PRINTD(("i2c_transfer: error: bus is busy\n"));
233 ret = -6; goto i2c_transfer_finish;
234
235i2c_transfer_finish:
236 PRINTD(("i2c_transfer: ISR: 0x%04x\n",ISR));
237 i2c_reset();
238 return ret;
239
240}
241
242/* ------------------------------------------------------------------------ */
243/* API Functions */
244/* ------------------------------------------------------------------------ */
245
246void i2c_init(int speed, int slaveaddr)
247{
wdenk47cd00f2003-03-06 13:39:27 +0000248#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. */
252 i2c_init_board();
253#endif
wdenk43d96162003-03-06 00:02:04 +0000254}
255
256
257/**
258 * i2c_probe: - Test if a chip answers for a given i2c address
259 *
260 * @chip: address of the chip which is searched for
261 * @return: 0 if a chip was found, -1 otherwhise
262 */
263
264int i2c_probe(uchar chip)
265{
266 struct i2c_msg msg;
267
268 i2c_reset();
269
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;
275
276 msg.condition = I2C_COND_STOP;
277 msg.acknack = I2C_ACKNAK_SENDNAK;
278 msg.direction = I2C_READ;
279 msg.data = 0x00;
280 if (i2c_transfer(&msg)) return -1;
281
282 return 0;
283}
284
285
286/**
287 * i2c_read: - Read multiple bytes from an i2c device
288 *
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)
291 *
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
298 */
299
300int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
301{
302 struct i2c_msg msg;
303 u8 addr_bytes[3]; /* lowest...highest byte of data address */
304 int ret;
305
306 PRINTD(("i2c_read(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len));
307
308 i2c_reset();
309
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);
316 msg.data &= 0xFE;
317 if ((ret=i2c_transfer(&msg))) return -1;
318
319 /*
320 * send memory address bytes;
321 * alen defines how much bytes we have to send.
322 */
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);
327
328 while (--alen >= 0) {
329
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;
336 }
337
338
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);
345 msg.data |= 0x01;
346 if ((ret=i2c_transfer(&msg))) return -1;
347
348 /* read bytes; send NACK at last byte */
349 while (len--) {
350
351 if (len==0) {
352 msg.condition = I2C_COND_STOP;
353 msg.acknack = I2C_ACKNAK_SENDNAK;
354 } else {
355 msg.condition = I2C_COND_NORMAL;
356 msg.acknack = I2C_ACKNAK_SENDACK;
357 }
358
359 msg.direction = I2C_READ;
360 msg.data = 0x00;
361 if ((ret=i2c_transfer(&msg))) return -1;
362
363 *(buffer++) = msg.data;
364
365 PRINTD(("i2c_read: reading byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer));
366
367 }
368
369 i2c_reset();
370
371 return 0;
372}
373
374
375/**
376 * i2c_write: - Write multiple bytes to an i2c device
377 *
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)
380 *
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
387 */
388
389int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
390{
391 struct i2c_msg msg;
392 u8 addr_bytes[3]; /* lowest...highest byte of data address */
393
394 PRINTD(("i2c_write(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len));
395
396 i2c_reset();
397
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);
404 msg.data &= 0xFE;
405 if (i2c_transfer(&msg)) return -1;
406
407 /*
408 * send memory address bytes;
409 * alen defines how much bytes we have to send.
410 */
411 addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF);
412 addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF);
413 addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
414
415 while (--alen >= 0) {
416
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;
423 }
424
425 /* write bytes; send NACK at last byte */
426 while (len--) {
427
428 PRINTD(("i2c_write: writing byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer));
429
430 if (len==0)
431 msg.condition = I2C_COND_STOP;
432 else
433 msg.condition = I2C_COND_NORMAL;
434
435 msg.acknack = I2C_ACKNAK_WAITACK;
436 msg.direction = I2C_WRITE;
437 msg.data = *(buffer++);
438
439 if (i2c_transfer(&msg)) return -1;
440
441 }
442
443 i2c_reset();
444
445 return 0;
446
447}
448
449uchar i2c_reg_read (uchar chip, uchar reg)
450{
451 PRINTD(("i2c_reg_read(chip=0x%02x, reg=0x%02x)\n",chip,reg));
452 return 0;
453}
454
455void i2c_reg_write(uchar chip, uchar reg, uchar val)
456{
457 PRINTD(("i2c_reg_write(chip=0x%02x, reg=0x%02x, val=0x%02x)\n",chip,reg,val));
458}
459
460#endif /* CONFIG_HARD_I2C */