2 i2c Support for Apple Keywest I2C Bus Controller
4 Copyright (c) 2001 Benjamin Herrenschmidt <benh@kernel.crashing.org>
8 Copyright (c) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
10 This program is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 2 of the License, or
13 (at your option) any later version.
15 This program is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with this program; if not, write to the Free Software
22 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26 2001/12/13 BenH New implementation
27 2001/12/15 BenH Add support for "byte" and "quick"
28 transfers. Add i2c_xfer routine.
29 2003/09/21 BenH Rework state machine with Paulus help
30 2004/01/21 BenH Merge in Greg KH changes, polled mode is back
31 2004/02/05 BenH Merge 64 bits fixes from the g5 ppc64 tree
33 My understanding of the various modes supported by keywest are:
35 - Dumb mode : not implemented, probably direct tweaking of lines
36 - Standard mode : simple i2c transaction of type
37 S Addr R/W A Data A Data ... T
38 - Standard sub mode : combined 8 bit subaddr write with data read
39 S Addr R/W A SubAddr A Data A Data ... T
40 - Combined mode : Subaddress and Data sequences appended with no stop
41 S Addr R/W A SubAddr S Addr R/W A Data A Data ... T
43 Currently, this driver uses only Standard mode for i2c xfer, and
44 smbus byte & quick transfers ; and uses StandardSub mode for
45 other smbus transfers instead of combined as we need that for the
46 sound driver to be happy
49 #include <linux/module.h>
50 #include <linux/kernel.h>
51 #include <linux/ioport.h>
52 #include <linux/pci.h>
53 #include <linux/types.h>
54 #include <linux/delay.h>
55 #include <linux/i2c.h>
56 #include <linux/init.h>
58 #include <linux/timer.h>
59 #include <linux/spinlock.h>
60 #include <linux/completion.h>
61 #include <linux/interrupt.h>
65 #include <asm/machdep.h>
66 #include <asm/pmac_feature.h>
67 #include <asm/pmac_low_i2c.h>
69 #include "i2c-keywest.h"
73 /* Some debug macros */
74 #define WRONG_STATE(name) do {\
75 pr_debug("KW: wrong state. Got %s, state: %s (isr: %02x)\n", \
76 name, __kw_state_names[iface->state], isr); \
80 static const char *__kw_state_names[] = {
90 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
91 MODULE_DESCRIPTION("I2C driver for Apple's Keywest");
92 MODULE_LICENSE("GPL");
95 /* Don't schedule, the g5 fan controller is too
99 wait_interrupt(struct keywest_iface* iface)
104 for (i = 0; i < 200000; i++) {
105 isr = read_reg(reg_isr) & KW_I2C_IRQ_MASK;
112 #endif /* POLLED_MODE */
115 do_stop(struct keywest_iface* iface, int result)
117 write_reg(reg_control, KW_I2C_CTL_STOP);
118 iface->state = state_stop;
119 iface->result = result;
122 /* Main state machine for standard & standard sub mode */
124 handle_interrupt(struct keywest_iface *iface, u8 isr)
129 if (iface->state != state_stop) {
130 pr_debug("KW: Timeout !\n");
131 do_stop(iface, -EIO);
133 if (iface->state == state_stop) {
134 ack = read_reg(reg_status);
135 if (!(ack & KW_I2C_STAT_BUSY)) {
136 iface->state = state_idle;
137 write_reg(reg_ier, 0x00);
139 complete(&iface->complete);
140 #endif /* POLLED_MODE */
146 if (isr & KW_I2C_IRQ_ADDR) {
147 ack = read_reg(reg_status);
148 if (iface->state != state_addr) {
149 write_reg(reg_isr, KW_I2C_IRQ_ADDR);
150 WRONG_STATE("KW_I2C_IRQ_ADDR");
151 do_stop(iface, -EIO);
154 if ((ack & KW_I2C_STAT_LAST_AAK) == 0) {
155 iface->state = state_stop;
156 iface->result = -ENODEV;
157 pr_debug("KW: NAK on address\n");
159 /* Handle rw "quick" mode */
160 if (iface->datalen == 0) {
162 } else if (iface->read_write == I2C_SMBUS_READ) {
163 iface->state = state_read;
164 if (iface->datalen > 1)
165 write_reg(reg_control, KW_I2C_CTL_AAK);
167 iface->state = state_write;
168 write_reg(reg_data, *(iface->data++));
172 write_reg(reg_isr, KW_I2C_IRQ_ADDR);
175 if (isr & KW_I2C_IRQ_DATA) {
176 if (iface->state == state_read) {
177 *(iface->data++) = read_reg(reg_data);
178 write_reg(reg_isr, KW_I2C_IRQ_DATA);
180 if (iface->datalen == 0)
181 iface->state = state_stop;
182 else if (iface->datalen == 1)
183 write_reg(reg_control, 0);
184 } else if (iface->state == state_write) {
185 /* Check ack status */
186 ack = read_reg(reg_status);
187 if ((ack & KW_I2C_STAT_LAST_AAK) == 0) {
188 pr_debug("KW: nack on data write (%x): %x\n",
189 iface->data[-1], ack);
190 do_stop(iface, -EIO);
191 } else if (iface->datalen) {
192 write_reg(reg_data, *(iface->data++));
195 write_reg(reg_control, KW_I2C_CTL_STOP);
196 iface->state = state_stop;
199 write_reg(reg_isr, KW_I2C_IRQ_DATA);
201 write_reg(reg_isr, KW_I2C_IRQ_DATA);
202 WRONG_STATE("KW_I2C_IRQ_DATA");
203 if (iface->state != state_stop)
204 do_stop(iface, -EIO);
208 if (isr & KW_I2C_IRQ_STOP) {
209 write_reg(reg_isr, KW_I2C_IRQ_STOP);
210 if (iface->state != state_stop) {
211 WRONG_STATE("KW_I2C_IRQ_STOP");
212 iface->result = -EIO;
214 iface->state = state_idle;
215 write_reg(reg_ier, 0x00);
217 complete(&iface->complete);
218 #endif /* POLLED_MODE */
221 if (isr & KW_I2C_IRQ_START)
222 write_reg(reg_isr, KW_I2C_IRQ_START);
227 /* Interrupt handler */
229 keywest_irq(int irq, void *dev_id, struct pt_regs *regs)
231 struct keywest_iface *iface = (struct keywest_iface *)dev_id;
234 spin_lock_irqsave(&iface->lock, flags);
235 del_timer(&iface->timeout_timer);
236 handle_interrupt(iface, read_reg(reg_isr));
237 if (iface->state != state_idle) {
238 iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
239 add_timer(&iface->timeout_timer);
241 spin_unlock_irqrestore(&iface->lock, flags);
246 keywest_timeout(unsigned long data)
248 struct keywest_iface *iface = (struct keywest_iface *)data;
251 pr_debug("timeout !\n");
252 spin_lock_irqsave(&iface->lock, flags);
253 handle_interrupt(iface, read_reg(reg_isr));
254 if (iface->state != state_idle) {
255 iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
256 add_timer(&iface->timeout_timer);
258 spin_unlock_irqrestore(&iface->lock, flags);
261 #endif /* POLLED_MODE */
264 * SMBUS-type transfer entrypoint
267 keywest_smbus_xfer( struct i2c_adapter* adap,
269 unsigned short flags,
273 union i2c_smbus_data* data)
275 struct keywest_chan* chan = i2c_get_adapdata(adap);
276 struct keywest_iface* iface = chan->iface;
282 if (iface->state == state_dead)
285 /* Prepare datas & select mode */
286 iface->cur_mode &= ~KW_I2C_MODE_MODE_MASK;
288 case I2C_SMBUS_QUICK:
291 iface->cur_mode |= KW_I2C_MODE_STANDARD;
295 buffer = &data->byte;
296 iface->cur_mode |= KW_I2C_MODE_STANDARD;
298 case I2C_SMBUS_BYTE_DATA:
300 buffer = &data->byte;
301 iface->cur_mode |= KW_I2C_MODE_STANDARDSUB;
303 case I2C_SMBUS_WORD_DATA:
305 cur_word = cpu_to_le16(data->word);
306 buffer = (u8 *)&cur_word;
307 iface->cur_mode |= KW_I2C_MODE_STANDARDSUB;
309 case I2C_SMBUS_BLOCK_DATA:
310 len = data->block[0];
311 buffer = &data->block[1];
312 iface->cur_mode |= KW_I2C_MODE_STANDARDSUB;
318 /* Turn a standardsub read into a combined mode access */
319 if (read_write == I2C_SMBUS_READ
320 && (iface->cur_mode & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_STANDARDSUB) {
321 iface->cur_mode &= ~KW_I2C_MODE_MODE_MASK;
322 iface->cur_mode |= KW_I2C_MODE_COMBINED;
325 /* Original driver had this limitation */
329 if (pmac_low_i2c_lock(iface->node))
332 pr_debug("chan: %d, addr: 0x%x, transfer len: %d, read: %d\n",
333 chan->chan_no, addr, len, read_write == I2C_SMBUS_READ);
335 iface->data = buffer;
336 iface->datalen = len;
337 iface->state = state_addr;
339 iface->read_write = read_write;
341 /* Setup channel & clear pending irqs */
342 write_reg(reg_isr, read_reg(reg_isr));
343 write_reg(reg_mode, iface->cur_mode | (chan->chan_no << 4));
344 write_reg(reg_status, 0);
346 /* Set up address and r/w bit */
348 (addr << 1) | ((read_write == I2C_SMBUS_READ) ? 0x01 : 0x00));
350 /* Set up the sub address */
351 if ((iface->cur_mode & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_STANDARDSUB
352 || (iface->cur_mode & KW_I2C_MODE_MODE_MASK) == KW_I2C_MODE_COMBINED)
353 write_reg(reg_subaddr, command);
357 iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
358 add_timer(&iface->timeout_timer);
361 /* Start sending address & enable interrupt*/
362 write_reg(reg_control, KW_I2C_CTL_XADDR);
363 write_reg(reg_ier, KW_I2C_IRQ_MASK);
366 pr_debug("using polled mode...\n");
367 /* State machine, to turn into an interrupt handler */
368 while(iface->state != state_idle) {
371 u8 isr = wait_interrupt(iface);
372 spin_lock_irqsave(&iface->lock, flags);
373 handle_interrupt(iface, isr);
374 spin_unlock_irqrestore(&iface->lock, flags);
376 #else /* POLLED_MODE */
377 pr_debug("using interrupt mode...\n");
378 wait_for_completion(&iface->complete);
379 #endif /* POLLED_MODE */
382 pr_debug("transfer done, result: %d\n", rc);
384 if (rc == 0 && size == I2C_SMBUS_WORD_DATA && read_write == I2C_SMBUS_READ)
385 data->word = le16_to_cpu(cur_word);
388 pmac_low_i2c_unlock(iface->node);
394 * Generic i2c master transfer entrypoint
397 keywest_xfer( struct i2c_adapter *adap,
398 struct i2c_msg *msgs,
401 struct keywest_chan* chan = i2c_get_adapdata(adap);
402 struct keywest_iface* iface = chan->iface;
403 struct i2c_msg *pmsg;
407 if (iface->state == state_dead)
410 if (pmac_low_i2c_lock(iface->node))
413 /* Set adapter to standard mode */
414 iface->cur_mode &= ~KW_I2C_MODE_MODE_MASK;
415 iface->cur_mode |= KW_I2C_MODE_STANDARD;
418 for (i = 0; rc >= 0 && i < num;) {
423 if (pmsg->flags & I2C_M_TEN) {
424 printk(KERN_ERR "i2c-keywest: 10 bits addr not supported !\n");
428 pr_debug("xfer: chan: %d, doing %s %d bytes to 0x%02x - %d of %d messages\n",
430 pmsg->flags & I2C_M_RD ? "read" : "write",
431 pmsg->len, addr, i, num);
433 /* Setup channel & clear pending irqs */
434 write_reg(reg_mode, iface->cur_mode | (chan->chan_no << 4));
435 write_reg(reg_isr, read_reg(reg_isr));
436 write_reg(reg_status, 0);
438 iface->data = pmsg->buf;
439 iface->datalen = pmsg->len;
440 iface->state = state_addr;
442 if (pmsg->flags & I2C_M_RD)
443 iface->read_write = I2C_SMBUS_READ;
445 iface->read_write = I2C_SMBUS_WRITE;
447 /* Set up address and r/w bit */
448 if (pmsg->flags & I2C_M_REV_DIR_ADDR)
452 ((iface->read_write == I2C_SMBUS_READ) ? 0x01 : 0x00));
456 iface->timeout_timer.expires = jiffies + POLL_TIMEOUT;
457 add_timer(&iface->timeout_timer);
460 /* Start sending address & enable interrupt*/
461 write_reg(reg_ier, KW_I2C_IRQ_MASK);
462 write_reg(reg_control, KW_I2C_CTL_XADDR);
465 pr_debug("using polled mode...\n");
466 /* State machine, to turn into an interrupt handler */
467 while(iface->state != state_idle) {
468 u8 isr = wait_interrupt(iface);
469 handle_interrupt(iface, isr);
471 #else /* POLLED_MODE */
472 pr_debug("using interrupt mode...\n");
473 wait_for_completion(&iface->complete);
474 #endif /* POLLED_MODE */
479 pr_debug("transfer done, result: %d\n", rc);
483 pmac_low_i2c_unlock(iface->node);
489 keywest_func(struct i2c_adapter * adapter)
491 return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
492 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
493 I2C_FUNC_SMBUS_BLOCK_DATA;
496 /* For now, we only handle combined mode (smbus) */
497 static struct i2c_algorithm keywest_algorithm = {
498 .smbus_xfer = keywest_smbus_xfer,
499 .master_xfer = keywest_xfer,
500 .functionality = keywest_func,
505 create_iface(struct device_node *np, struct device *dev)
508 unsigned bsteps, tsize, i, nchan, addroffset;
509 struct keywest_iface* iface;
513 if (np->n_intrs < 1 || np->n_addrs < 1) {
514 printk(KERN_ERR "%s: Missing interrupt or address !\n",
518 if (pmac_low_i2c_lock(np))
521 psteps = (u32 *)get_property(np, "AAPL,address-step", NULL);
522 steps = psteps ? (*psteps) : 0x10;
524 /* Hrm... maybe we can be smarter here */
525 for (bsteps = 0; (steps & 0x01) == 0; bsteps++)
528 if (np->parent->name[0] == 'u') {
536 tsize = sizeof(struct keywest_iface) +
537 (sizeof(struct keywest_chan) + 4) * nchan;
538 iface = (struct keywest_iface *) kmalloc(tsize, GFP_KERNEL);
540 printk(KERN_ERR "i2c-keywest: can't allocate inteface !\n");
541 pmac_low_i2c_unlock(np);
544 memset(iface, 0, tsize);
545 spin_lock_init(&iface->lock);
546 init_completion(&iface->complete);
547 iface->node = of_node_get(np);
548 iface->bsteps = bsteps;
549 iface->chan_count = nchan;
550 iface->state = state_idle;
551 iface->irq = np->intrs[0].line;
552 iface->channels = (struct keywest_chan *)
553 (((unsigned long)(iface + 1) + 3UL) & ~3UL);
554 iface->base = ioremap(np->addrs[0].address + addroffset,
557 printk(KERN_ERR "i2c-keywest: can't map inteface !\n");
559 pmac_low_i2c_unlock(np);
564 init_timer(&iface->timeout_timer);
565 iface->timeout_timer.function = keywest_timeout;
566 iface->timeout_timer.data = (unsigned long)iface;
569 /* Select interface rate */
570 iface->cur_mode = KW_I2C_MODE_100KHZ;
571 prate = (u32 *)get_property(np, "AAPL,i2c-rate", NULL);
572 if (prate) switch(*prate) {
574 iface->cur_mode = KW_I2C_MODE_100KHZ;
577 iface->cur_mode = KW_I2C_MODE_50KHZ;
580 iface->cur_mode = KW_I2C_MODE_25KHZ;
583 printk(KERN_WARNING "i2c-keywest: unknown rate %ldKhz, using 100KHz\n",
587 /* Select standard mode by default */
588 iface->cur_mode |= KW_I2C_MODE_STANDARD;
591 write_reg(reg_mode, iface->cur_mode);
593 /* Switch interrupts off & clear them*/
594 write_reg(reg_ier, 0x00);
595 write_reg(reg_isr, KW_I2C_IRQ_MASK);
598 /* Request chip interrupt */
599 rc = request_irq(iface->irq, keywest_irq, SA_INTERRUPT, "keywest i2c", iface);
601 printk(KERN_ERR "i2c-keywest: can't get IRQ %d !\n", iface->irq);
602 iounmap(iface->base);
604 pmac_low_i2c_unlock(np);
607 #endif /* POLLED_MODE */
609 pmac_low_i2c_unlock(np);
610 dev_set_drvdata(dev, iface);
612 for (i=0; i<nchan; i++) {
613 struct keywest_chan* chan = &iface->channels[i];
616 sprintf(chan->adapter.name, "%s %d", np->parent->name, i);
619 chan->adapter.algo = &keywest_algorithm;
620 chan->adapter.algo_data = NULL;
621 chan->adapter.client_register = NULL;
622 chan->adapter.client_unregister = NULL;
623 i2c_set_adapdata(&chan->adapter, chan);
624 chan->adapter.dev.parent = dev;
626 rc = i2c_add_adapter(&chan->adapter);
628 printk("i2c-keywest.c: Adapter %s registration failed\n",
630 i2c_set_adapdata(&chan->adapter, NULL);
634 printk(KERN_INFO "Found KeyWest i2c on \"%s\", %d channel%s, stepping: %d bits\n",
635 np->parent->name, nchan, nchan > 1 ? "s" : "", bsteps);
641 dispose_iface(struct device *dev)
643 struct keywest_iface *iface = dev_get_drvdata(dev);
646 /* Make sure we stop all activity */
647 if (pmac_low_i2c_lock(iface->node))
651 spin_lock_irq(&iface->lock);
652 while (iface->state != state_idle) {
653 spin_unlock_irq(&iface->lock);
655 spin_lock_irq(&iface->lock);
657 #endif /* POLLED_MODE */
658 iface->state = state_dead;
660 spin_unlock_irq(&iface->lock);
661 free_irq(iface->irq, iface);
662 #endif /* POLLED_MODE */
664 pmac_low_i2c_unlock(iface->node);
666 /* Release all channels */
667 for (i=0; i<iface->chan_count; i++) {
668 struct keywest_chan* chan = &iface->channels[i];
669 if (i2c_get_adapdata(&chan->adapter) == NULL)
671 rc = i2c_del_adapter(&chan->adapter);
672 i2c_set_adapdata(&chan->adapter, NULL);
673 /* We aren't that prepared to deal with this... */
675 printk("i2c-keywest.c: i2c_del_adapter failed, that's bad !\n");
677 iounmap(iface->base);
678 dev_set_drvdata(dev, NULL);
679 of_node_put(iface->node);
686 create_iface_macio(struct macio_dev* dev, const struct of_device_id *match)
688 return create_iface(dev->ofdev.node, &dev->ofdev.dev);
692 dispose_iface_macio(struct macio_dev* dev)
694 return dispose_iface(&dev->ofdev.dev);
698 create_iface_of_platform(struct of_device* dev, const struct of_device_id *match)
700 return create_iface(dev->node, &dev->dev);
704 dispose_iface_of_platform(struct of_device* dev)
706 return dispose_iface(&dev->dev);
709 static struct of_device_id i2c_keywest_match[] =
713 .compatible = "keywest"
718 static struct macio_driver i2c_keywest_macio_driver =
720 .name = "i2c-keywest",
721 .match_table = i2c_keywest_match,
722 .probe = create_iface_macio,
723 .remove = dispose_iface_macio
726 static struct of_platform_driver i2c_keywest_of_platform_driver =
728 .name = "i2c-keywest",
729 .match_table = i2c_keywest_match,
730 .probe = create_iface_of_platform,
731 .remove = dispose_iface_of_platform
735 i2c_keywest_init(void)
737 of_register_driver(&i2c_keywest_of_platform_driver);
738 macio_register_driver(&i2c_keywest_macio_driver);
744 i2c_keywest_cleanup(void)
746 of_unregister_driver(&i2c_keywest_of_platform_driver);
747 macio_unregister_driver(&i2c_keywest_macio_driver);
750 module_init(i2c_keywest_init);
751 module_exit(i2c_keywest_cleanup);