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/pxa-regs.h>
47 //#define DEBUG_I2C 1 /* activate local debugging output */
48 #define I2C_PXA_SLAVE_ADDR 0x1 /* slave pxa unit address */
49 #define I2C_ICR_INIT (ICR_BEIE | ICR_IRFIE | ICR_ITEIE | ICR_GCD | ICR_SCLE)
50 #define I2C_ISR_INIT 0x7FF
53 #define PRINTD(x) printf x
59 /* Shall the current transfer have a start/stop condition? */
60 #define I2C_COND_NORMAL 0
61 #define I2C_COND_START 1
62 #define I2C_COND_STOP 2
64 /* Shall the current transfer be ack/nacked or being waited for it? */
65 #define I2C_ACKNAK_WAITACK 1
66 #define I2C_ACKNAK_SENDACK 2
67 #define I2C_ACKNAK_SENDNAK 4
69 /* Specify who shall transfer the data (master or slave) */
73 /* All transfers are described by this data structure */
83 * i2c_pxa_reset: - reset the host controller
87 static void i2c_reset( void )
89 ICR &= ~ICR_IUE; /* disable unit */
90 ICR |= ICR_UR; /* reset the unit */
92 ICR &= ~ICR_IUE; /* disable unit */
93 CKEN |= CKEN14_I2C; /* set the global I2C clock on */
94 ISAR = I2C_PXA_SLAVE_ADDR; /* set our slave address */
95 ICR = I2C_ICR_INIT; /* set control register values */
96 ISR = I2C_ISR_INIT; /* set clear interrupt bits */
97 ICR |= ICR_IUE; /* enable unit */
103 * i2c_isr_set_cleared: - wait until certain bits of the I2C status register
104 * are set and cleared
106 * @return: 0 in case of success, 1 means timeout (no match within 10 ms).
109 static int i2c_isr_set_cleared( unsigned long set_mask, unsigned long cleared_mask )
113 while( ((ISR & set_mask)!=set_mask) || ((ISR & cleared_mask)!=0) ){
115 if( timeout-- < 0 ) return 0;
123 * i2c_transfer: - Transfer one byte over the i2c bus
125 * This function can tranfer a byte over the i2c bus in both directions.
126 * It is used by the public API functions.
128 * @return: 0: transfer successful
129 * -1: message is empty
130 * -2: transmit timeout
132 * -4: receive timeout
133 * -5: illegal parameters
134 * -6: bus is busy and couldn't be aquired
136 int i2c_transfer(struct i2c_msg *msg)
141 goto transfer_error_msg_empty;
143 switch(msg->direction) {
147 /* check if bus is not busy */
148 if (!i2c_isr_set_cleared(0,ISR_IBB))
149 goto transfer_error_bus_busy;
151 /* start transmission */
155 if (msg->condition == I2C_COND_START) ICR |= ICR_START;
156 if (msg->condition == I2C_COND_STOP) ICR |= ICR_STOP;
157 if (msg->acknack == I2C_ACKNAK_SENDNAK) ICR |= ICR_ACKNAK;
158 if (msg->acknack == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK;
162 /* transmit register empty? */
163 if (!i2c_isr_set_cleared(ISR_ITE,0))
164 goto transfer_error_transmit_timeout;
166 /* clear 'transmit empty' state */
169 /* wait for ACK from slave */
170 if (msg->acknack == I2C_ACKNAK_WAITACK)
171 if (!i2c_isr_set_cleared(0,ISR_ACKNAK))
172 goto transfer_error_ack_missing;
177 /* check if bus is not busy */
178 if (!i2c_isr_set_cleared(0,ISR_IBB))
179 goto transfer_error_bus_busy;
184 if (msg->condition == I2C_COND_START) ICR |= ICR_START;
185 if (msg->condition == I2C_COND_STOP) ICR |= ICR_STOP;
186 if (msg->acknack == I2C_ACKNAK_SENDNAK) ICR |= ICR_ACKNAK;
187 if (msg->acknack == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK;
191 /* receive register full? */
192 if (!i2c_isr_set_cleared(ISR_IRF,0))
193 goto transfer_error_receive_timeout;
197 /* clear 'receive empty' state */
204 goto transfer_error_illegal_param;
210 transfer_error_msg_empty:
211 PRINTD(("i2c_transfer: error: 'msg' is empty\n"));
212 ret = -1; goto i2c_transfer_finish;
214 transfer_error_transmit_timeout:
215 PRINTD(("i2c_transfer: error: transmit timeout\n"));
216 ret = -2; goto i2c_transfer_finish;
218 transfer_error_ack_missing:
219 PRINTD(("i2c_transfer: error: ACK missing\n"));
220 ret = -3; goto i2c_transfer_finish;
222 transfer_error_receive_timeout:
223 PRINTD(("i2c_transfer: error: receive timeout\n"));
224 ret = -4; goto i2c_transfer_finish;
226 transfer_error_illegal_param:
227 PRINTD(("i2c_transfer: error: illegal parameters\n"));
228 ret = -5; goto i2c_transfer_finish;
230 transfer_error_bus_busy:
231 PRINTD(("i2c_transfer: error: bus is busy\n"));
232 ret = -6; goto i2c_transfer_finish;
235 PRINTD(("i2c_transfer: ISR: 0x%04x\n",ISR));
241 /* ------------------------------------------------------------------------ */
243 /* ------------------------------------------------------------------------ */
245 void i2c_init(int speed, int slaveaddr)
251 * i2c_probe: - Test if a chip answers for a given i2c address
253 * @chip: address of the chip which is searched for
254 * @return: 0 if a chip was found, -1 otherwhise
257 int i2c_probe(uchar chip)
263 msg.condition = I2C_COND_START;
264 msg.acknack = I2C_ACKNAK_WAITACK;
265 msg.direction = I2C_WRITE;
266 msg.data = (chip << 1) + 1;
267 if (i2c_transfer(&msg)) return -1;
269 msg.condition = I2C_COND_STOP;
270 msg.acknack = I2C_ACKNAK_SENDNAK;
271 msg.direction = I2C_READ;
273 if (i2c_transfer(&msg)) return -1;
280 * i2c_read: - Read multiple bytes from an i2c device
282 * The higher level routines take into account that this function is only
283 * called with len < page length of the device (see configuration file)
285 * @chip: address of the chip which is to be read
286 * @addr: i2c data address within the chip
287 * @alen: length of the i2c data address (1..2 bytes)
288 * @buffer: where to write the data
289 * @len: how much byte do we want to read
290 * @return: 0 in case of success
293 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
296 u8 addr_bytes[3]; /* lowest...highest byte of data address */
299 PRINTD(("i2c_read(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len));
303 /* dummy chip address write */
304 PRINTD(("i2c_read: dummy chip address write\n"));
305 msg.condition = I2C_COND_START;
306 msg.acknack = I2C_ACKNAK_WAITACK;
307 msg.direction = I2C_WRITE;
308 msg.data = (chip << 1);
310 if ((ret=i2c_transfer(&msg))) return -1;
313 * send memory address bytes;
314 * alen defines how much bytes we have to send.
316 //addr &= ((1 << CFG_EEPROM_PAGE_WRITE_BITS)-1);
317 addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF);
318 addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF);
319 addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
321 while (--alen >= 0) {
323 PRINTD(("i2c_read: send memory word address byte %1d\n",alen));
324 msg.condition = I2C_COND_NORMAL;
325 msg.acknack = I2C_ACKNAK_WAITACK;
326 msg.direction = I2C_WRITE;
327 msg.data = addr_bytes[alen];
328 if ((ret=i2c_transfer(&msg))) return -1;
332 /* start read sequence */
333 PRINTD(("i2c_read: start read sequence\n"));
334 msg.condition = I2C_COND_START;
335 msg.acknack = I2C_ACKNAK_WAITACK;
336 msg.direction = I2C_WRITE;
337 msg.data = (chip << 1);
339 if ((ret=i2c_transfer(&msg))) return -1;
341 /* read bytes; send NACK at last byte */
345 msg.condition = I2C_COND_STOP;
346 msg.acknack = I2C_ACKNAK_SENDNAK;
348 msg.condition = I2C_COND_NORMAL;
349 msg.acknack = I2C_ACKNAK_SENDACK;
352 msg.direction = I2C_READ;
354 if ((ret=i2c_transfer(&msg))) return -1;
356 *(buffer++) = msg.data;
358 PRINTD(("i2c_read: reading byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer));
369 * i2c_write: - Write multiple bytes to an i2c device
371 * The higher level routines take into account that this function is only
372 * called with len < page length of the device (see configuration file)
374 * @chip: address of the chip which is to be written
375 * @addr: i2c data address within the chip
376 * @alen: length of the i2c data address (1..2 bytes)
377 * @buffer: where to find the data to be written
378 * @len: how much byte do we want to read
379 * @return: 0 in case of success
382 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
385 u8 addr_bytes[3]; /* lowest...highest byte of data address */
387 PRINTD(("i2c_write(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len));
391 /* chip address write */
392 PRINTD(("i2c_write: chip address write\n"));
393 msg.condition = I2C_COND_START;
394 msg.acknack = I2C_ACKNAK_WAITACK;
395 msg.direction = I2C_WRITE;
396 msg.data = (chip << 1);
398 if (i2c_transfer(&msg)) return -1;
401 * send memory address bytes;
402 * alen defines how much bytes we have to send.
404 addr_bytes[0] = (u8)((addr >> 0) & 0x000000FF);
405 addr_bytes[1] = (u8)((addr >> 8) & 0x000000FF);
406 addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
408 while (--alen >= 0) {
410 PRINTD(("i2c_write: send memory word address\n"));
411 msg.condition = I2C_COND_NORMAL;
412 msg.acknack = I2C_ACKNAK_WAITACK;
413 msg.direction = I2C_WRITE;
414 msg.data = addr_bytes[alen];
415 if (i2c_transfer(&msg)) return -1;
418 /* write bytes; send NACK at last byte */
421 PRINTD(("i2c_write: writing byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer));
424 msg.condition = I2C_COND_STOP;
426 msg.condition = I2C_COND_NORMAL;
428 msg.acknack = I2C_ACKNAK_WAITACK;
429 msg.direction = I2C_WRITE;
430 msg.data = *(buffer++);
432 if (i2c_transfer(&msg)) return -1;
442 uchar i2c_reg_read (uchar chip, uchar reg)
444 PRINTD(("i2c_reg_read(chip=0x%02x, reg=0x%02x)\n",chip,reg));
448 void i2c_reg_write(uchar chip, uchar reg, uchar val)
450 PRINTD(("i2c_reg_write(chip=0x%02x, reg=0x%02x, val=0x%02x)\n",chip,reg,val));
453 #endif /* CONFIG_HARD_I2C */