i2c-pxa.c 21.9 KB
Newer Older
Russell King's avatar
Russell King committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
/*
 *  i2c_adap_pxa.c
 *
 *  I2C adapter for the PXA I2C bus access.
 *
 *  Copyright (C) 2002 Intrinsyc Software Inc.
 *  Copyright (C) 2004-2005 Deep Blue Solutions Ltd.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  History:
 *    Apr 2002: Initial version [CS]
 *    Jun 2002: Properly seperated algo/adap [FB]
 *    Jan 2003: Fixed several bugs concerning interrupt handling [Kai-Uwe Bloem]
 *    Jan 2003: added limited signal handling [Kai-Uwe Bloem]
 *    Sep 2004: Major rework to ensure efficient bus handling [RMK]
 *    Dec 2004: Added support for PXA27x and slave device probing [Liam Girdwood]
 *    Feb 2005: Rework slave mode handling [RMK]
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/i2c-id.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/i2c-pxa.h>
33
#include <linux/platform_device.h>
Russell King's avatar
Russell King committed
34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100

#include <asm/hardware.h>
#include <asm/irq.h>
#include <asm/arch/i2c.h>
#include <asm/arch/pxa-regs.h>

struct pxa_i2c {
	spinlock_t		lock;
	wait_queue_head_t	wait;
	struct i2c_msg		*msg;
	unsigned int		msg_num;
	unsigned int		msg_idx;
	unsigned int		msg_ptr;
	unsigned int		slave_addr;

	struct i2c_adapter	adap;
#ifdef CONFIG_I2C_PXA_SLAVE
	struct i2c_slave_client *slave;
#endif

	unsigned int		irqlogidx;
	u32			isrlog[32];
	u32			icrlog[32];
};

/*
 * I2C Slave mode address
 */
#define I2C_PXA_SLAVE_ADDR      0x1

#ifdef DEBUG

struct bits {
	u32	mask;
	const char *set;
	const char *unset;
};
#define BIT(m, s, u)	{ .mask = m, .set = s, .unset = u }

static inline void
decode_bits(const char *prefix, const struct bits *bits, int num, u32 val)
{
	printk("%s %08x: ", prefix, val);
	while (num--) {
		const char *str = val & bits->mask ? bits->set : bits->unset;
		if (str)
			printk("%s ", str);
		bits++;
	}
}

static const struct bits isr_bits[] = {
	BIT(ISR_RWM,	"RX",		"TX"),
	BIT(ISR_ACKNAK,	"NAK",		"ACK"),
	BIT(ISR_UB,	"Bsy",		"Rdy"),
	BIT(ISR_IBB,	"BusBsy",	"BusRdy"),
	BIT(ISR_SSD,	"SlaveStop",	NULL),
	BIT(ISR_ALD,	"ALD",		NULL),
	BIT(ISR_ITE,	"TxEmpty",	NULL),
	BIT(ISR_IRF,	"RxFull",	NULL),
	BIT(ISR_GCAD,	"GenCall",	NULL),
	BIT(ISR_SAD,	"SlaveAddr",	NULL),
	BIT(ISR_BED,	"BusErr",	NULL),
};

static void decode_ISR(unsigned int val)
{
101
	decode_bits(KERN_DEBUG "ISR", isr_bits, ARRAY_SIZE(isr_bits), val);
Russell King's avatar
Russell King committed
102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124
	printk("\n");
}

static const struct bits icr_bits[] = {
	BIT(ICR_START,  "START",	NULL),
	BIT(ICR_STOP,   "STOP",		NULL),
	BIT(ICR_ACKNAK, "ACKNAK",	NULL),
	BIT(ICR_TB,     "TB",		NULL),
	BIT(ICR_MA,     "MA",		NULL),
	BIT(ICR_SCLE,   "SCLE",		"scle"),
	BIT(ICR_IUE,    "IUE",		"iue"),
	BIT(ICR_GCD,    "GCD",		NULL),
	BIT(ICR_ITEIE,  "ITEIE",	NULL),
	BIT(ICR_IRFIE,  "IRFIE",	NULL),
	BIT(ICR_BEIE,   "BEIE",		NULL),
	BIT(ICR_SSDIE,  "SSDIE",	NULL),
	BIT(ICR_ALDIE,  "ALDIE",	NULL),
	BIT(ICR_SADIE,  "SADIE",	NULL),
	BIT(ICR_UR,     "UR",		"ur"),
};

static void decode_ICR(unsigned int val)
{
125
	decode_bits(KERN_DEBUG "ICR", icr_bits, ARRAY_SIZE(icr_bits), val);
Russell King's avatar
Russell King committed
126 127 128 129 130 131 132
	printk("\n");
}

static unsigned int i2c_debug = DEBUG;

static void i2c_pxa_show_state(struct pxa_i2c *i2c, int lno, const char *fname)
{
133
	dev_dbg(&i2c->adap.dev, "state:%s:%d: ISR=%08x, ICR=%08x, IBMR=%02x\n", fname, lno, ISR, ICR, IBMR);
Russell King's avatar
Russell King committed
134 135 136 137 138 139 140 141 142 143 144
}

#define show_state(i2c) i2c_pxa_show_state(i2c, __LINE__, __FUNCTION__)
#else
#define i2c_debug	0

#define show_state(i2c) do { } while (0)
#define decode_ISR(val) do { } while (0)
#define decode_ICR(val) do { } while (0)
#endif

145
#define eedbg(lvl, x...) do { if ((lvl) < 1) { printk(KERN_DEBUG "" x); } } while(0)
Russell King's avatar
Russell King committed
146 147 148 149 150 151 152 153 154

static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret);

static void i2c_pxa_scream_blue_murder(struct pxa_i2c *i2c, const char *why)
{
	unsigned int i;
	printk("i2c: error: %s\n", why);
	printk("i2c: msg_num: %d msg_idx: %d msg_ptr: %d\n",
		i2c->msg_num, i2c->msg_idx, i2c->msg_ptr);
155 156
	printk("i2c: ICR: %08x ISR: %08x\n"
	       "i2c: log: ", ICR, ISR);
Russell King's avatar
Russell King committed
157 158 159 160 161 162 163 164 165 166 167 168 169 170 171
	for (i = 0; i < i2c->irqlogidx; i++)
		printk("[%08x:%08x] ", i2c->isrlog[i], i2c->icrlog[i]);
	printk("\n");
}

static inline int i2c_pxa_is_slavemode(struct pxa_i2c *i2c)
{
	return !(ICR & ICR_SCLE);
}

static void i2c_pxa_abort(struct pxa_i2c *i2c)
{
	unsigned long timeout = jiffies + HZ/4;

	if (i2c_pxa_is_slavemode(i2c)) {
172
		dev_dbg(&i2c->adap.dev, "%s: called in slave mode\n", __func__);
Russell King's avatar
Russell King committed
173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215
		return;
	}

	while (time_before(jiffies, timeout) && (IBMR & 0x1) == 0) {
		unsigned long icr = ICR;

		icr &= ~ICR_START;
		icr |= ICR_ACKNAK | ICR_STOP | ICR_TB;

		ICR = icr;

		show_state(i2c);

		msleep(1);
	}

	ICR &= ~(ICR_MA | ICR_START | ICR_STOP);
}

static int i2c_pxa_wait_bus_not_busy(struct pxa_i2c *i2c)
{
	int timeout = DEF_TIMEOUT;

	while (timeout-- && ISR & (ISR_IBB | ISR_UB)) {
		if ((ISR & ISR_SAD) != 0)
			timeout += 4;

		msleep(2);
		show_state(i2c);
	}

	if (timeout <= 0)
		show_state(i2c);

	return timeout <= 0 ? I2C_RETRY : 0;
}

static int i2c_pxa_wait_master(struct pxa_i2c *i2c)
{
	unsigned long timeout = jiffies + HZ*4;

	while (time_before(jiffies, timeout)) {
		if (i2c_debug > 1)
216 217
			dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
				__func__, (long)jiffies, ISR, ICR, IBMR);
Russell King's avatar
Russell King committed
218 219 220

		if (ISR & ISR_SAD) {
			if (i2c_debug > 0)
221
				dev_dbg(&i2c->adap.dev, "%s: Slave detected\n", __func__);
Russell King's avatar
Russell King committed
222 223 224 225 226 227 228 229 230
			goto out;
		}

		/* wait for unit and bus being not busy, and we also do a
		 * quick check of the i2c lines themselves to ensure they've
		 * gone high...
		 */
		if ((ISR & (ISR_UB | ISR_IBB)) == 0 && IBMR == 3) {
			if (i2c_debug > 0)
231
				dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
Russell King's avatar
Russell King committed
232 233 234 235 236 237 238
			return 1;
		}

		msleep(1);
	}

	if (i2c_debug > 0)
239
		dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
Russell King's avatar
Russell King committed
240 241 242 243 244 245 246
 out:
	return 0;
}

static int i2c_pxa_set_master(struct pxa_i2c *i2c)
{
	if (i2c_debug)
247
		dev_dbg(&i2c->adap.dev, "setting to bus master\n");
Russell King's avatar
Russell King committed
248 249

	if ((ISR & (ISR_UB | ISR_IBB)) != 0) {
250
		dev_dbg(&i2c->adap.dev, "%s: unit is busy\n", __func__);
Russell King's avatar
Russell King committed
251
		if (!i2c_pxa_wait_master(i2c)) {
252
			dev_dbg(&i2c->adap.dev, "%s: error: unit busy\n", __func__);
Russell King's avatar
Russell King committed
253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271
			return I2C_RETRY;
		}
	}

	ICR |= ICR_SCLE;
	return 0;
}

#ifdef CONFIG_I2C_PXA_SLAVE
static int i2c_pxa_wait_slave(struct pxa_i2c *i2c)
{
	unsigned long timeout = jiffies + HZ*1;

	/* wait for stop */

	show_state(i2c);

	while (time_before(jiffies, timeout)) {
		if (i2c_debug > 1)
272 273
			dev_dbg(&i2c->adap.dev, "%s: %ld: ISR=%08x, ICR=%08x, IBMR=%02x\n",
				__func__, (long)jiffies, ISR, ICR, IBMR);
Russell King's avatar
Russell King committed
274 275 276 277

		if ((ISR & (ISR_UB|ISR_IBB|ISR_SAD)) == ISR_SAD ||
		    (ICR & ICR_SCLE) == 0) {
			if (i2c_debug > 1)
278
				dev_dbg(&i2c->adap.dev, "%s: done\n", __func__);
Russell King's avatar
Russell King committed
279 280 281 282 283 284 285
			return 1;
		}

		msleep(1);
	}

	if (i2c_debug > 0)
286
		dev_dbg(&i2c->adap.dev, "%s: did not free\n", __func__);
Russell King's avatar
Russell King committed
287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309
	return 0;
}

/*
 * clear the hold on the bus, and take of anything else
 * that has been configured
 */
static void i2c_pxa_set_slave(struct pxa_i2c *i2c, int errcode)
{
	show_state(i2c);

	if (errcode < 0) {
		udelay(100);   /* simple delay */
	} else {
		/* we need to wait for the stop condition to end */

		/* if we where in stop, then clear... */
		if (ICR & ICR_STOP) {
			udelay(100);
			ICR &= ~ICR_STOP;
		}

		if (!i2c_pxa_wait_slave(i2c)) {
310 311
			dev_err(&i2c->adap.dev, "%s: wait timedout\n",
				__func__);
Russell King's avatar
Russell King committed
312 313 314 315 316 317 318 319
			return;
		}
	}

	ICR &= ~(ICR_STOP|ICR_ACKNAK|ICR_MA);
	ICR &= ~ICR_SCLE;

	if (i2c_debug) {
320
		dev_dbg(&i2c->adap.dev, "ICR now %08x, ISR %08x\n", ICR, ISR);
Russell King's avatar
Russell King committed
321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345
		decode_ICR(ICR);
	}
}
#else
#define i2c_pxa_set_slave(i2c, err)	do { } while (0)
#endif

static void i2c_pxa_reset(struct pxa_i2c *i2c)
{
	pr_debug("Resetting I2C Controller Unit\n");

	/* abort any transfer currently under way */
	i2c_pxa_abort(i2c);

	/* reset according to 9.8 */
	ICR = ICR_UR;
	ISR = I2C_ISR_INIT;
	ICR &= ~ICR_UR;

	ISAR = i2c->slave_addr;

	/* set control register values */
	ICR = I2C_ICR_INIT;

#ifdef CONFIG_I2C_PXA_SLAVE
346
	dev_info(&i2c->adap.dev, "Enabling slave mode\n");
Russell King's avatar
Russell King committed
347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516
	ICR |= ICR_SADIE | ICR_ALDIE | ICR_SSDIE;
#endif

	i2c_pxa_set_slave(i2c, 0);

	/* enable unit */
	ICR |= ICR_IUE;
	udelay(100);
}


#ifdef CONFIG_I2C_PXA_SLAVE
/*
 * I2C EEPROM emulation.
 */
static struct i2c_eeprom_emu eeprom = {
	.size = I2C_EEPROM_EMU_SIZE,
	.watch = LIST_HEAD_INIT(eeprom.watch),
};

struct i2c_eeprom_emu *i2c_pxa_get_eeprom(void)
{
	return &eeprom;
}

int i2c_eeprom_emu_addwatcher(struct i2c_eeprom_emu *emu, void *data,
			      unsigned int addr, unsigned int size,
			      struct i2c_eeprom_emu_watcher *watcher)
{
	struct i2c_eeprom_emu_watch *watch;
	unsigned long flags;

	if (addr + size > emu->size)
		return -EINVAL;

	watch = kmalloc(sizeof(struct i2c_eeprom_emu_watch), GFP_KERNEL);
	if (watch) {
		watch->start = addr;
		watch->end = addr + size - 1;
		watch->ops = watcher;
		watch->data = data;

		local_irq_save(flags);
		list_add(&watch->node, &emu->watch);
		local_irq_restore(flags);
	}

	return watch ? 0 : -ENOMEM;
}

void i2c_eeprom_emu_delwatcher(struct i2c_eeprom_emu *emu, void *data,
			       struct i2c_eeprom_emu_watcher *watcher)
{
	struct i2c_eeprom_emu_watch *watch, *n;
	unsigned long flags;

	list_for_each_entry_safe(watch, n, &emu->watch, node) {
		if (watch->ops == watcher && watch->data == data) {
			local_irq_save(flags);
			list_del(&watch->node);
			local_irq_restore(flags);
			kfree(watch);
		}
	}
}

static void i2c_eeprom_emu_event(void *ptr, i2c_slave_event_t event)
{
	struct i2c_eeprom_emu *emu = ptr;

	eedbg(3, "i2c_eeprom_emu_event: %d\n", event);

	switch (event) {
	case I2C_SLAVE_EVENT_START_WRITE:
		emu->seen_start = 1;
		eedbg(2, "i2c_eeprom: write initiated\n");
		break;

	case I2C_SLAVE_EVENT_START_READ:
		emu->seen_start = 0;
		eedbg(2, "i2c_eeprom: read initiated\n");
		break;

	case I2C_SLAVE_EVENT_STOP:
		emu->seen_start = 0;
		eedbg(2, "i2c_eeprom: received stop\n");
		break;

	default:
		eedbg(0, "i2c_eeprom: unhandled event\n");
		break;
	}
}

static int i2c_eeprom_emu_read(void *ptr)
{
	struct i2c_eeprom_emu *emu = ptr;
	int ret;

	ret = emu->bytes[emu->ptr];
	emu->ptr = (emu->ptr + 1) % emu->size;

	return ret;
}

static void i2c_eeprom_emu_write(void *ptr, unsigned int val)
{
	struct i2c_eeprom_emu *emu = ptr;
	struct i2c_eeprom_emu_watch *watch;

	if (emu->seen_start != 0) {
		eedbg(2, "i2c_eeprom_emu_write: setting ptr %02x\n", val);
		emu->ptr = val;
		emu->seen_start = 0;
		return;
	}

	emu->bytes[emu->ptr] = val;

	eedbg(1, "i2c_eeprom_emu_write: ptr=0x%02x, val=0x%02x\n",
	      emu->ptr, val);

	list_for_each_entry(watch, &emu->watch, node) {
		if (!watch->ops || !watch->ops->write)
			continue;
		if (watch->start <= emu->ptr && watch->end >= emu->ptr)
			watch->ops->write(watch->data, emu->ptr, val);
	}

	emu->ptr = (emu->ptr + 1) % emu->size;
}

struct i2c_slave_client eeprom_client = {
	.data	= &eeprom,
	.event	= i2c_eeprom_emu_event,
	.read	= i2c_eeprom_emu_read,
	.write	= i2c_eeprom_emu_write
};

/*
 * PXA I2C Slave mode
 */

static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
{
	if (isr & ISR_BED) {
		/* what should we do here? */
	} else {
		int ret = i2c->slave->read(i2c->slave->data);

		IDBR = ret;
		ICR |= ICR_TB;   /* allow next byte */
	}
}

static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
{
	unsigned int byte = IDBR;

	if (i2c->slave != NULL)
		i2c->slave->write(i2c->slave->data, byte);

	ICR |= ICR_TB;
}

static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
{
	int timeout;

	if (i2c_debug > 0)
517
		dev_dbg(&i2c->adap.dev, "SAD, mode is slave-%cx\n",
Russell King's avatar
Russell King committed
518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540
		       (isr & ISR_RWM) ? 'r' : 't');

	if (i2c->slave != NULL)
		i2c->slave->event(i2c->slave->data,
				 (isr & ISR_RWM) ? I2C_SLAVE_EVENT_START_READ : I2C_SLAVE_EVENT_START_WRITE);

	/*
	 * slave could interrupt in the middle of us generating a
	 * start condition... if this happens, we'd better back off
	 * and stop holding the poor thing up
	 */
	ICR &= ~(ICR_START|ICR_STOP);
	ICR |= ICR_TB;

	timeout = 0x10000;

	while (1) {
		if ((IBMR & 2) == 2)
			break;

		timeout--;

		if (timeout <= 0) {
541
			dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
Russell King's avatar
Russell King committed
542 543 544 545 546 547 548 549 550 551
			break;
		}
	}

	ICR &= ~ICR_SCLE;
}

static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
{
	if (i2c_debug > 2)
552
		dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop)\n");
Russell King's avatar
Russell King committed
553 554 555 556 557

	if (i2c->slave != NULL)
		i2c->slave->event(i2c->slave->data, I2C_SLAVE_EVENT_STOP);

	if (i2c_debug > 2)
558
		dev_dbg(&i2c->adap.dev, "ISR: SSD (Slave Stop) acked\n");
Russell King's avatar
Russell King committed
559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603

	/*
	 * If we have a master-mode message waiting,
	 * kick it off now that the slave has completed.
	 */
	if (i2c->msg)
		i2c_pxa_master_complete(i2c, I2C_RETRY);
}
#else
static void i2c_pxa_slave_txempty(struct pxa_i2c *i2c, u32 isr)
{
	if (isr & ISR_BED) {
		/* what should we do here? */
	} else {
		IDBR = 0;
		ICR |= ICR_TB;
	}
}

static void i2c_pxa_slave_rxfull(struct pxa_i2c *i2c, u32 isr)
{
	ICR |= ICR_TB | ICR_ACKNAK;
}

static void i2c_pxa_slave_start(struct pxa_i2c *i2c, u32 isr)
{
	int timeout;

	/*
	 * slave could interrupt in the middle of us generating a
	 * start condition... if this happens, we'd better back off
	 * and stop holding the poor thing up
	 */
	ICR &= ~(ICR_START|ICR_STOP);
	ICR |= ICR_TB | ICR_ACKNAK;

	timeout = 0x10000;

	while (1) {
		if ((IBMR & 2) == 2)
			break;

		timeout--;

		if (timeout <= 0) {
604
			dev_err(&i2c->adap.dev, "timeout waiting for SCL high\n");
Russell King's avatar
Russell King committed
605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649
			break;
		}
	}

	ICR &= ~ICR_SCLE;
}

static void i2c_pxa_slave_stop(struct pxa_i2c *i2c)
{
	if (i2c->msg)
		i2c_pxa_master_complete(i2c, I2C_RETRY);
}
#endif

/*
 * PXA I2C Master mode
 */

static inline unsigned int i2c_pxa_addr_byte(struct i2c_msg *msg)
{
	unsigned int addr = (msg->addr & 0x7f) << 1;

	if (msg->flags & I2C_M_RD)
		addr |= 1;

	return addr;
}

static inline void i2c_pxa_start_message(struct pxa_i2c *i2c)
{
	u32 icr;

	/*
	 * Step 1: target slave address into IDBR
	 */
	IDBR = i2c_pxa_addr_byte(i2c->msg);

	/*
	 * Step 2: initiate the write.
	 */
	icr = ICR & ~(ICR_STOP | ICR_ALDIE);
	ICR = icr | ICR_START | ICR_TB;
}

/*
650
 * We are protected by the adapter bus mutex.
Russell King's avatar
Russell King committed
651 652 653 654 655 656 657 658 659 660 661
 */
static int i2c_pxa_do_xfer(struct pxa_i2c *i2c, struct i2c_msg *msg, int num)
{
	long timeout;
	int ret;

	/*
	 * Wait for the bus to become free.
	 */
	ret = i2c_pxa_wait_bus_not_busy(i2c);
	if (ret) {
662
		dev_err(&i2c->adap.dev, "i2c_pxa: timeout waiting for bus free\n");
Russell King's avatar
Russell King committed
663 664 665 666 667 668 669 670
		goto out;
	}

	/*
	 * Set master mode.
	 */
	ret = i2c_pxa_set_master(i2c);
	if (ret) {
671
		dev_err(&i2c->adap.dev, "i2c_pxa_set_master: error %d\n", ret);
Russell King's avatar
Russell King committed
672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858
		goto out;
	}

	spin_lock_irq(&i2c->lock);

	i2c->msg = msg;
	i2c->msg_num = num;
	i2c->msg_idx = 0;
	i2c->msg_ptr = 0;
	i2c->irqlogidx = 0;

	i2c_pxa_start_message(i2c);

	spin_unlock_irq(&i2c->lock);

	/*
	 * The rest of the processing occurs in the interrupt handler.
	 */
	timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);

	/*
	 * We place the return code in i2c->msg_idx.
	 */
	ret = i2c->msg_idx;

	if (timeout == 0)
		i2c_pxa_scream_blue_murder(i2c, "timeout");

 out:
	return ret;
}

/*
 * i2c_pxa_master_complete - complete the message and wake up.
 */
static void i2c_pxa_master_complete(struct pxa_i2c *i2c, int ret)
{
	i2c->msg_ptr = 0;
	i2c->msg = NULL;
	i2c->msg_idx ++;
	i2c->msg_num = 0;
	if (ret)
		i2c->msg_idx = ret;
	wake_up(&i2c->wait);
}

static void i2c_pxa_irq_txempty(struct pxa_i2c *i2c, u32 isr)
{
	u32 icr = ICR & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);

 again:
	/*
	 * If ISR_ALD is set, we lost arbitration.
	 */
	if (isr & ISR_ALD) {
		/*
		 * Do we need to do anything here?  The PXA docs
		 * are vague about what happens.
		 */
		i2c_pxa_scream_blue_murder(i2c, "ALD set");

		/*
		 * We ignore this error.  We seem to see spurious ALDs
		 * for seemingly no reason.  If we handle them as I think
		 * they should, we end up causing an I2C error, which
		 * is painful for some systems.
		 */
		return; /* ignore */
	}

	if (isr & ISR_BED) {
		int ret = BUS_ERROR;

		/*
		 * I2C bus error - either the device NAK'd us, or
		 * something more serious happened.  If we were NAK'd
		 * on the initial address phase, we can retry.
		 */
		if (isr & ISR_ACKNAK) {
			if (i2c->msg_ptr == 0 && i2c->msg_idx == 0)
				ret = I2C_RETRY;
			else
				ret = XFER_NAKED;
		}
		i2c_pxa_master_complete(i2c, ret);
	} else if (isr & ISR_RWM) {
		/*
		 * Read mode.  We have just sent the address byte, and
		 * now we must initiate the transfer.
		 */
		if (i2c->msg_ptr == i2c->msg->len - 1 &&
		    i2c->msg_idx == i2c->msg_num - 1)
			icr |= ICR_STOP | ICR_ACKNAK;

		icr |= ICR_ALDIE | ICR_TB;
	} else if (i2c->msg_ptr < i2c->msg->len) {
		/*
		 * Write mode.  Write the next data byte.
		 */
		IDBR = i2c->msg->buf[i2c->msg_ptr++];

		icr |= ICR_ALDIE | ICR_TB;

		/*
		 * If this is the last byte of the last message, send
		 * a STOP.
		 */
		if (i2c->msg_ptr == i2c->msg->len &&
		    i2c->msg_idx == i2c->msg_num - 1)
			icr |= ICR_STOP;
	} else if (i2c->msg_idx < i2c->msg_num - 1) {
		/*
		 * Next segment of the message.
		 */
		i2c->msg_ptr = 0;
		i2c->msg_idx ++;
		i2c->msg++;

		/*
		 * If we aren't doing a repeated start and address,
		 * go back and try to send the next byte.  Note that
		 * we do not support switching the R/W direction here.
		 */
		if (i2c->msg->flags & I2C_M_NOSTART)
			goto again;

		/*
		 * Write the next address.
		 */
		IDBR = i2c_pxa_addr_byte(i2c->msg);

		/*
		 * And trigger a repeated start, and send the byte.
		 */
		icr &= ~ICR_ALDIE;
		icr |= ICR_START | ICR_TB;
	} else {
		if (i2c->msg->len == 0) {
			/*
			 * Device probes have a message length of zero
			 * and need the bus to be reset before it can
			 * be used again.
			 */
			i2c_pxa_reset(i2c);
		}
		i2c_pxa_master_complete(i2c, 0);
	}

	i2c->icrlog[i2c->irqlogidx-1] = icr;

	ICR = icr;
	show_state(i2c);
}

static void i2c_pxa_irq_rxfull(struct pxa_i2c *i2c, u32 isr)
{
	u32 icr = ICR & ~(ICR_START|ICR_STOP|ICR_ACKNAK|ICR_TB);

	/*
	 * Read the byte.
	 */
	i2c->msg->buf[i2c->msg_ptr++] = IDBR;

	if (i2c->msg_ptr < i2c->msg->len) {
		/*
		 * If this is the last byte of the last
		 * message, send a STOP.
		 */
		if (i2c->msg_ptr == i2c->msg->len - 1)
			icr |= ICR_STOP | ICR_ACKNAK;

		icr |= ICR_ALDIE | ICR_TB;
	} else {
		i2c_pxa_master_complete(i2c, 0);
	}

	i2c->icrlog[i2c->irqlogidx-1] = icr;

	ICR = icr;
}

static irqreturn_t i2c_pxa_handler(int this_irq, void *dev_id, struct pt_regs *regs)
{
	struct pxa_i2c *i2c = dev_id;
	u32 isr = ISR;

	if (i2c_debug > 2 && 0) {
859 860
		dev_dbg(&i2c->adap.dev, "%s: ISR=%08x, ICR=%08x, IBMR=%02x\n",
			__func__, isr, ICR, IBMR);
Russell King's avatar
Russell King committed
861 862 863
		decode_ISR(isr);
	}

864
	if (i2c->irqlogidx < ARRAY_SIZE(i2c->isrlog))
Russell King's avatar
Russell King committed
865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901
		i2c->isrlog[i2c->irqlogidx++] = isr;

	show_state(i2c);

	/*
	 * Always clear all pending IRQs.
	 */
	ISR = isr & (ISR_SSD|ISR_ALD|ISR_ITE|ISR_IRF|ISR_SAD|ISR_BED);

	if (isr & ISR_SAD)
		i2c_pxa_slave_start(i2c, isr);
	if (isr & ISR_SSD)
		i2c_pxa_slave_stop(i2c);

	if (i2c_pxa_is_slavemode(i2c)) {
		if (isr & ISR_ITE)
			i2c_pxa_slave_txempty(i2c, isr);
		if (isr & ISR_IRF)
			i2c_pxa_slave_rxfull(i2c, isr);
	} else if (i2c->msg) {
		if (isr & ISR_ITE)
			i2c_pxa_irq_txempty(i2c, isr);
		if (isr & ISR_IRF)
			i2c_pxa_irq_rxfull(i2c, isr);
	} else {
		i2c_pxa_scream_blue_murder(i2c, "spurious irq");
	}

	return IRQ_HANDLED;
}


static int i2c_pxa_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
{
	struct pxa_i2c *i2c = adap->algo_data;
	int ret, i;

902 903 904 905 906 907
	/* If the I2C controller is disabled we need to reset it (probably due
 	   to a suspend/resume destroying state). We do this here as we can then
 	   avoid worrying about resuming the controller before its users. */
	if (!(ICR & ICR_IUE))
		i2c_pxa_reset(i2c);

Russell King's avatar
Russell King committed
908 909 910 911 912 913
	for (i = adap->retries; i >= 0; i--) {
		ret = i2c_pxa_do_xfer(i2c, msgs, num);
		if (ret != I2C_RETRY)
			goto out;

		if (i2c_debug)
914
			dev_dbg(&adap->dev, "Retrying transmission\n");
Russell King's avatar
Russell King committed
915 916 917 918 919 920 921 922 923
		udelay(100);
	}
	i2c_pxa_scream_blue_murder(i2c, "exhausted retries");
	ret = -EREMOTEIO;
 out:
	i2c_pxa_set_slave(i2c, ret);
	return ret;
}

924 925 926 927 928
static u32 i2c_pxa_functionality(struct i2c_adapter *adap)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

Russell King's avatar
Russell King committed
929 930
static struct i2c_algorithm i2c_pxa_algorithm = {
	.master_xfer	= i2c_pxa_xfer,
931
	.functionality	= i2c_pxa_functionality,
Russell King's avatar
Russell King committed
932 933 934 935 936 937
};

static struct pxa_i2c i2c_pxa = {
	.lock	= SPIN_LOCK_UNLOCKED,
	.wait	= __WAIT_QUEUE_HEAD_INITIALIZER(i2c_pxa.wait),
	.adap	= {
938
		.owner		= THIS_MODULE,
Russell King's avatar
Russell King committed
939
		.algo		= &i2c_pxa_algorithm,
940
		.name		= "pxa2xx-i2c",
Russell King's avatar
Russell King committed
941 942 943 944
		.retries	= 5,
	},
};

945
static int i2c_pxa_probe(struct platform_device *dev)
Russell King's avatar
Russell King committed
946 947
{
	struct pxa_i2c *i2c = &i2c_pxa;
948
#ifdef CONFIG_I2C_PXA_SLAVE
949
	struct i2c_pxa_platform_data *plat = dev->dev.platform_data;
950
#endif
Russell King's avatar
Russell King committed
951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970
	int ret;

#ifdef CONFIG_PXA27x
	pxa_gpio_mode(GPIO117_I2CSCL_MD);
	pxa_gpio_mode(GPIO118_I2CSDA_MD);
	udelay(100);
#endif

	i2c->slave_addr = I2C_PXA_SLAVE_ADDR;

#ifdef CONFIG_I2C_PXA_SLAVE
	i2c->slave = &eeprom_client;
	if (plat) {
		i2c->slave_addr = plat->slave_addr;
		if (plat->slave)
			i2c->slave = plat->slave;
	}
#endif

	pxa_set_cken(CKEN14_I2C, 1);
971
	ret = request_irq(IRQ_I2C, i2c_pxa_handler, IRQF_DISABLED,
Russell King's avatar
Russell King committed
972 973 974 975 976 977 978
			  "pxa2xx-i2c", i2c);
	if (ret)
		goto out;

	i2c_pxa_reset(i2c);

	i2c->adap.algo_data = i2c;
979
	i2c->adap.dev.parent = &dev->dev;
Russell King's avatar
Russell King committed
980 981 982 983 984 985 986

	ret = i2c_add_adapter(&i2c->adap);
	if (ret < 0) {
		printk(KERN_INFO "I2C: Failed to add bus\n");
		goto err_irq;
	}

987
	platform_set_drvdata(dev, i2c);
Russell King's avatar
Russell King committed
988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003

#ifdef CONFIG_I2C_PXA_SLAVE
	printk(KERN_INFO "I2C: %s: PXA I2C adapter, slave address %d\n",
	       i2c->adap.dev.bus_id, i2c->slave_addr);
#else
	printk(KERN_INFO "I2C: %s: PXA I2C adapter\n",
	       i2c->adap.dev.bus_id);
#endif
	return 0;

 err_irq:
	free_irq(IRQ_I2C, i2c);
 out:
	return ret;
}

1004
static int i2c_pxa_remove(struct platform_device *dev)
Russell King's avatar
Russell King committed
1005
{
1006
	struct pxa_i2c *i2c = platform_get_drvdata(dev);
Russell King's avatar
Russell King committed
1007

1008
	platform_set_drvdata(dev, NULL);
Russell King's avatar
Russell King committed
1009 1010 1011 1012 1013 1014 1015 1016

	i2c_del_adapter(&i2c->adap);
	free_irq(IRQ_I2C, i2c);
	pxa_set_cken(CKEN14_I2C, 0);

	return 0;
}

1017
static struct platform_driver i2c_pxa_driver = {
Russell King's avatar
Russell King committed
1018 1019
	.probe		= i2c_pxa_probe,
	.remove		= i2c_pxa_remove,
1020 1021 1022
	.driver		= {
		.name	= "pxa2xx-i2c",
	},
Russell King's avatar
Russell King committed
1023 1024 1025 1026
};

static int __init i2c_adap_pxa_init(void)
{
1027
	return platform_driver_register(&i2c_pxa_driver);
Russell King's avatar
Russell King committed
1028 1029 1030 1031
}

static void i2c_adap_pxa_exit(void)
{
1032
	return platform_driver_unregister(&i2c_pxa_driver);
Russell King's avatar
Russell King committed
1033 1034
}

1035 1036
MODULE_LICENSE("GPL");

Russell King's avatar
Russell King committed
1037 1038
module_init(i2c_adap_pxa_init);
module_exit(i2c_adap_pxa_exit);