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/drivers/i2c/busses/i2c-ocores.c

http://github.com/mirrors/linux
C | 818 lines | 612 code | 120 blank | 86 comment | 114 complexity | bb17dd1a3e776e9b17defe13b8c07fdd MD5 | raw file
  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * i2c-ocores.c: I2C bus driver for OpenCores I2C controller
  4 * (https://opencores.org/project/i2c/overview)
  5 *
  6 * Peter Korsgaard <peter@korsgaard.com>
  7 *
  8 * Support for the GRLIB port of the controller by
  9 * Andreas Larsson <andreas@gaisler.com>
 10 */
 11
 12#include <linux/clk.h>
 13#include <linux/delay.h>
 14#include <linux/err.h>
 15#include <linux/kernel.h>
 16#include <linux/module.h>
 17#include <linux/errno.h>
 18#include <linux/platform_device.h>
 19#include <linux/i2c.h>
 20#include <linux/interrupt.h>
 21#include <linux/wait.h>
 22#include <linux/platform_data/i2c-ocores.h>
 23#include <linux/slab.h>
 24#include <linux/io.h>
 25#include <linux/log2.h>
 26#include <linux/spinlock.h>
 27#include <linux/jiffies.h>
 28
 29/*
 30 * 'process_lock' exists because ocores_process() and ocores_process_timeout()
 31 * can't run in parallel.
 32 */
 33struct ocores_i2c {
 34	void __iomem *base;
 35	int iobase;
 36	u32 reg_shift;
 37	u32 reg_io_width;
 38	unsigned long flags;
 39	wait_queue_head_t wait;
 40	struct i2c_adapter adap;
 41	struct i2c_msg *msg;
 42	int pos;
 43	int nmsgs;
 44	int state; /* see STATE_ */
 45	spinlock_t process_lock;
 46	struct clk *clk;
 47	int ip_clock_khz;
 48	int bus_clock_khz;
 49	void (*setreg)(struct ocores_i2c *i2c, int reg, u8 value);
 50	u8 (*getreg)(struct ocores_i2c *i2c, int reg);
 51};
 52
 53/* registers */
 54#define OCI2C_PRELOW		0
 55#define OCI2C_PREHIGH		1
 56#define OCI2C_CONTROL		2
 57#define OCI2C_DATA		3
 58#define OCI2C_CMD		4 /* write only */
 59#define OCI2C_STATUS		4 /* read only, same address as OCI2C_CMD */
 60
 61#define OCI2C_CTRL_IEN		0x40
 62#define OCI2C_CTRL_EN		0x80
 63
 64#define OCI2C_CMD_START		0x91
 65#define OCI2C_CMD_STOP		0x41
 66#define OCI2C_CMD_READ		0x21
 67#define OCI2C_CMD_WRITE		0x11
 68#define OCI2C_CMD_READ_ACK	0x21
 69#define OCI2C_CMD_READ_NACK	0x29
 70#define OCI2C_CMD_IACK		0x01
 71
 72#define OCI2C_STAT_IF		0x01
 73#define OCI2C_STAT_TIP		0x02
 74#define OCI2C_STAT_ARBLOST	0x20
 75#define OCI2C_STAT_BUSY		0x40
 76#define OCI2C_STAT_NACK		0x80
 77
 78#define STATE_DONE		0
 79#define STATE_START		1
 80#define STATE_WRITE		2
 81#define STATE_READ		3
 82#define STATE_ERROR		4
 83
 84#define TYPE_OCORES		0
 85#define TYPE_GRLIB		1
 86#define TYPE_SIFIVE_REV0	2
 87
 88#define OCORES_FLAG_BROKEN_IRQ BIT(1) /* Broken IRQ for FU540-C000 SoC */
 89
 90static void oc_setreg_8(struct ocores_i2c *i2c, int reg, u8 value)
 91{
 92	iowrite8(value, i2c->base + (reg << i2c->reg_shift));
 93}
 94
 95static void oc_setreg_16(struct ocores_i2c *i2c, int reg, u8 value)
 96{
 97	iowrite16(value, i2c->base + (reg << i2c->reg_shift));
 98}
 99
100static void oc_setreg_32(struct ocores_i2c *i2c, int reg, u8 value)
101{
102	iowrite32(value, i2c->base + (reg << i2c->reg_shift));
103}
104
105static void oc_setreg_16be(struct ocores_i2c *i2c, int reg, u8 value)
106{
107	iowrite16be(value, i2c->base + (reg << i2c->reg_shift));
108}
109
110static void oc_setreg_32be(struct ocores_i2c *i2c, int reg, u8 value)
111{
112	iowrite32be(value, i2c->base + (reg << i2c->reg_shift));
113}
114
115static inline u8 oc_getreg_8(struct ocores_i2c *i2c, int reg)
116{
117	return ioread8(i2c->base + (reg << i2c->reg_shift));
118}
119
120static inline u8 oc_getreg_16(struct ocores_i2c *i2c, int reg)
121{
122	return ioread16(i2c->base + (reg << i2c->reg_shift));
123}
124
125static inline u8 oc_getreg_32(struct ocores_i2c *i2c, int reg)
126{
127	return ioread32(i2c->base + (reg << i2c->reg_shift));
128}
129
130static inline u8 oc_getreg_16be(struct ocores_i2c *i2c, int reg)
131{
132	return ioread16be(i2c->base + (reg << i2c->reg_shift));
133}
134
135static inline u8 oc_getreg_32be(struct ocores_i2c *i2c, int reg)
136{
137	return ioread32be(i2c->base + (reg << i2c->reg_shift));
138}
139
140static void oc_setreg_io_8(struct ocores_i2c *i2c, int reg, u8 value)
141{
142	outb(value, i2c->iobase + reg);
143}
144
145static inline u8 oc_getreg_io_8(struct ocores_i2c *i2c, int reg)
146{
147	return inb(i2c->iobase + reg);
148}
149
150static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
151{
152	i2c->setreg(i2c, reg, value);
153}
154
155static inline u8 oc_getreg(struct ocores_i2c *i2c, int reg)
156{
157	return i2c->getreg(i2c, reg);
158}
159
160static void ocores_process(struct ocores_i2c *i2c, u8 stat)
161{
162	struct i2c_msg *msg = i2c->msg;
163	unsigned long flags;
164
165	/*
166	 * If we spin here is because we are in timeout, so we are going
167	 * to be in STATE_ERROR. See ocores_process_timeout()
168	 */
169	spin_lock_irqsave(&i2c->process_lock, flags);
170
171	if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) {
172		/* stop has been sent */
173		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
174		wake_up(&i2c->wait);
175		goto out;
176	}
177
178	/* error? */
179	if (stat & OCI2C_STAT_ARBLOST) {
180		i2c->state = STATE_ERROR;
181		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
182		goto out;
183	}
184
185	if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) {
186		i2c->state =
187			(msg->flags & I2C_M_RD) ? STATE_READ : STATE_WRITE;
188
189		if (stat & OCI2C_STAT_NACK) {
190			i2c->state = STATE_ERROR;
191			oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
192			goto out;
193		}
194	} else {
195		msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);
196	}
197
198	/* end of msg? */
199	if (i2c->pos == msg->len) {
200		i2c->nmsgs--;
201		i2c->msg++;
202		i2c->pos = 0;
203		msg = i2c->msg;
204
205		if (i2c->nmsgs) {	/* end? */
206			/* send start? */
207			if (!(msg->flags & I2C_M_NOSTART)) {
208				u8 addr = i2c_8bit_addr_from_msg(msg);
209
210				i2c->state = STATE_START;
211
212				oc_setreg(i2c, OCI2C_DATA, addr);
213				oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
214				goto out;
215			}
216			i2c->state = (msg->flags & I2C_M_RD)
217				? STATE_READ : STATE_WRITE;
218		} else {
219			i2c->state = STATE_DONE;
220			oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
221			goto out;
222		}
223	}
224
225	if (i2c->state == STATE_READ) {
226		oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len-1) ?
227			  OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);
228	} else {
229		oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);
230		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);
231	}
232
233out:
234	spin_unlock_irqrestore(&i2c->process_lock, flags);
235}
236
237static irqreturn_t ocores_isr(int irq, void *dev_id)
238{
239	struct ocores_i2c *i2c = dev_id;
240	u8 stat = oc_getreg(i2c, OCI2C_STATUS);
241
242	if (i2c->flags & OCORES_FLAG_BROKEN_IRQ) {
243		if ((stat & OCI2C_STAT_IF) && !(stat & OCI2C_STAT_BUSY))
244			return IRQ_NONE;
245	} else if (!(stat & OCI2C_STAT_IF)) {
246		return IRQ_NONE;
247	}
248	ocores_process(i2c, stat);
249
250	return IRQ_HANDLED;
251}
252
253/**
254 * Process timeout event
255 * @i2c: ocores I2C device instance
256 */
257static void ocores_process_timeout(struct ocores_i2c *i2c)
258{
259	unsigned long flags;
260
261	spin_lock_irqsave(&i2c->process_lock, flags);
262	i2c->state = STATE_ERROR;
263	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
264	spin_unlock_irqrestore(&i2c->process_lock, flags);
265}
266
267/**
268 * Wait until something change in a given register
269 * @i2c: ocores I2C device instance
270 * @reg: register to query
271 * @mask: bitmask to apply on register value
272 * @val: expected result
273 * @timeout: timeout in jiffies
274 *
275 * Timeout is necessary to avoid to stay here forever when the chip
276 * does not answer correctly.
277 *
278 * Return: 0 on success, -ETIMEDOUT on timeout
279 */
280static int ocores_wait(struct ocores_i2c *i2c,
281		       int reg, u8 mask, u8 val,
282		       const unsigned long timeout)
283{
284	unsigned long j;
285
286	j = jiffies + timeout;
287	while (1) {
288		u8 status = oc_getreg(i2c, reg);
289
290		if ((status & mask) == val)
291			break;
292
293		if (time_after(jiffies, j))
294			return -ETIMEDOUT;
295	}
296	return 0;
297}
298
299/**
300 * Wait until is possible to process some data
301 * @i2c: ocores I2C device instance
302 *
303 * Used when the device is in polling mode (interrupts disabled).
304 *
305 * Return: 0 on success, -ETIMEDOUT on timeout
306 */
307static int ocores_poll_wait(struct ocores_i2c *i2c)
308{
309	u8 mask;
310	int err;
311
312	if (i2c->state == STATE_DONE || i2c->state == STATE_ERROR) {
313		/* transfer is over */
314		mask = OCI2C_STAT_BUSY;
315	} else {
316		/* on going transfer */
317		mask = OCI2C_STAT_TIP;
318		/*
319		 * We wait for the data to be transferred (8bit),
320		 * then we start polling on the ACK/NACK bit
321		 */
322		udelay((8 * 1000) / i2c->bus_clock_khz);
323	}
324
325	/*
326	 * once we are here we expect to get the expected result immediately
327	 * so if after 1ms we timeout then something is broken.
328	 */
329	err = ocores_wait(i2c, OCI2C_STATUS, mask, 0, msecs_to_jiffies(1));
330	if (err)
331		dev_warn(i2c->adap.dev.parent,
332			 "%s: STATUS timeout, bit 0x%x did not clear in 1ms\n",
333			 __func__, mask);
334	return err;
335}
336
337/**
338 * It handles an IRQ-less transfer
339 * @i2c: ocores I2C device instance
340 *
341 * Even if IRQ are disabled, the I2C OpenCore IP behavior is exactly the same
342 * (only that IRQ are not produced). This means that we can re-use entirely
343 * ocores_isr(), we just add our polling code around it.
344 *
345 * It can run in atomic context
346 */
347static void ocores_process_polling(struct ocores_i2c *i2c)
348{
349	while (1) {
350		irqreturn_t ret;
351		int err;
352
353		err = ocores_poll_wait(i2c);
354		if (err) {
355			i2c->state = STATE_ERROR;
356			break; /* timeout */
357		}
358
359		ret = ocores_isr(-1, i2c);
360		if (ret == IRQ_NONE)
361			break; /* all messages have been transferred */
362		else {
363			if (i2c->flags & OCORES_FLAG_BROKEN_IRQ)
364				if (i2c->state == STATE_DONE)
365					break;
366		}
367	}
368}
369
370static int ocores_xfer_core(struct ocores_i2c *i2c,
371			    struct i2c_msg *msgs, int num,
372			    bool polling)
373{
374	int ret;
375	u8 ctrl;
376
377	ctrl = oc_getreg(i2c, OCI2C_CONTROL);
378	if (polling)
379		oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~OCI2C_CTRL_IEN);
380	else
381		oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN);
382
383	i2c->msg = msgs;
384	i2c->pos = 0;
385	i2c->nmsgs = num;
386	i2c->state = STATE_START;
387
388	oc_setreg(i2c, OCI2C_DATA, i2c_8bit_addr_from_msg(i2c->msg));
389	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
390
391	if (polling) {
392		ocores_process_polling(i2c);
393	} else {
394		ret = wait_event_timeout(i2c->wait,
395					 (i2c->state == STATE_ERROR) ||
396					 (i2c->state == STATE_DONE), HZ);
397		if (ret == 0) {
398			ocores_process_timeout(i2c);
399			return -ETIMEDOUT;
400		}
401	}
402
403	return (i2c->state == STATE_DONE) ? num : -EIO;
404}
405
406static int ocores_xfer_polling(struct i2c_adapter *adap,
407			       struct i2c_msg *msgs, int num)
408{
409	return ocores_xfer_core(i2c_get_adapdata(adap), msgs, num, true);
410}
411
412static int ocores_xfer(struct i2c_adapter *adap,
413		       struct i2c_msg *msgs, int num)
414{
415	return ocores_xfer_core(i2c_get_adapdata(adap), msgs, num, false);
416}
417
418static int ocores_init(struct device *dev, struct ocores_i2c *i2c)
419{
420	int prescale;
421	int diff;
422	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
423
424	/* make sure the device is disabled */
425	ctrl &= ~(OCI2C_CTRL_EN | OCI2C_CTRL_IEN);
426	oc_setreg(i2c, OCI2C_CONTROL, ctrl);
427
428	prescale = (i2c->ip_clock_khz / (5 * i2c->bus_clock_khz)) - 1;
429	prescale = clamp(prescale, 0, 0xffff);
430
431	diff = i2c->ip_clock_khz / (5 * (prescale + 1)) - i2c->bus_clock_khz;
432	if (abs(diff) > i2c->bus_clock_khz / 10) {
433		dev_err(dev,
434			"Unsupported clock settings: core: %d KHz, bus: %d KHz\n",
435			i2c->ip_clock_khz, i2c->bus_clock_khz);
436		return -EINVAL;
437	}
438
439	oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff);
440	oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8);
441
442	/* Init the device */
443	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
444	oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_EN);
445
446	return 0;
447}
448
449
450static u32 ocores_func(struct i2c_adapter *adap)
451{
452	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
453}
454
455static struct i2c_algorithm ocores_algorithm = {
456	.master_xfer = ocores_xfer,
457	.master_xfer_atomic = ocores_xfer_polling,
458	.functionality = ocores_func,
459};
460
461static const struct i2c_adapter ocores_adapter = {
462	.owner = THIS_MODULE,
463	.name = "i2c-ocores",
464	.class = I2C_CLASS_DEPRECATED,
465	.algo = &ocores_algorithm,
466};
467
468static const struct of_device_id ocores_i2c_match[] = {
469	{
470		.compatible = "opencores,i2c-ocores",
471		.data = (void *)TYPE_OCORES,
472	},
473	{
474		.compatible = "aeroflexgaisler,i2cmst",
475		.data = (void *)TYPE_GRLIB,
476	},
477	{
478		.compatible = "sifive,fu540-c000-i2c",
479		.data = (void *)TYPE_SIFIVE_REV0,
480	},
481	{
482		.compatible = "sifive,i2c0",
483		.data = (void *)TYPE_SIFIVE_REV0,
484	},
485	{},
486};
487MODULE_DEVICE_TABLE(of, ocores_i2c_match);
488
489#ifdef CONFIG_OF
490/*
491 * Read and write functions for the GRLIB port of the controller. Registers are
492 * 32-bit big endian and the PRELOW and PREHIGH registers are merged into one
493 * register. The subsequent registers have their offsets decreased accordingly.
494 */
495static u8 oc_getreg_grlib(struct ocores_i2c *i2c, int reg)
496{
497	u32 rd;
498	int rreg = reg;
499
500	if (reg != OCI2C_PRELOW)
501		rreg--;
502	rd = ioread32be(i2c->base + (rreg << i2c->reg_shift));
503	if (reg == OCI2C_PREHIGH)
504		return (u8)(rd >> 8);
505	else
506		return (u8)rd;
507}
508
509static void oc_setreg_grlib(struct ocores_i2c *i2c, int reg, u8 value)
510{
511	u32 curr, wr;
512	int rreg = reg;
513
514	if (reg != OCI2C_PRELOW)
515		rreg--;
516	if (reg == OCI2C_PRELOW || reg == OCI2C_PREHIGH) {
517		curr = ioread32be(i2c->base + (rreg << i2c->reg_shift));
518		if (reg == OCI2C_PRELOW)
519			wr = (curr & 0xff00) | value;
520		else
521			wr = (((u32)value) << 8) | (curr & 0xff);
522	} else {
523		wr = value;
524	}
525	iowrite32be(wr, i2c->base + (rreg << i2c->reg_shift));
526}
527
528static int ocores_i2c_of_probe(struct platform_device *pdev,
529				struct ocores_i2c *i2c)
530{
531	struct device_node *np = pdev->dev.of_node;
532	const struct of_device_id *match;
533	u32 val;
534	u32 clock_frequency;
535	bool clock_frequency_present;
536
537	if (of_property_read_u32(np, "reg-shift", &i2c->reg_shift)) {
538		/* no 'reg-shift', check for deprecated 'regstep' */
539		if (!of_property_read_u32(np, "regstep", &val)) {
540			if (!is_power_of_2(val)) {
541				dev_err(&pdev->dev, "invalid regstep %d\n",
542					val);
543				return -EINVAL;
544			}
545			i2c->reg_shift = ilog2(val);
546			dev_warn(&pdev->dev,
547				"regstep property deprecated, use reg-shift\n");
548		}
549	}
550
551	clock_frequency_present = !of_property_read_u32(np, "clock-frequency",
552							&clock_frequency);
553	i2c->bus_clock_khz = 100;
554
555	i2c->clk = devm_clk_get(&pdev->dev, NULL);
556
557	if (!IS_ERR(i2c->clk)) {
558		int ret = clk_prepare_enable(i2c->clk);
559
560		if (ret) {
561			dev_err(&pdev->dev,
562				"clk_prepare_enable failed: %d\n", ret);
563			return ret;
564		}
565		i2c->ip_clock_khz = clk_get_rate(i2c->clk) / 1000;
566		if (clock_frequency_present)
567			i2c->bus_clock_khz = clock_frequency / 1000;
568	}
569
570	if (i2c->ip_clock_khz == 0) {
571		if (of_property_read_u32(np, "opencores,ip-clock-frequency",
572						&val)) {
573			if (!clock_frequency_present) {
574				dev_err(&pdev->dev,
575					"Missing required parameter 'opencores,ip-clock-frequency'\n");
576				clk_disable_unprepare(i2c->clk);
577				return -ENODEV;
578			}
579			i2c->ip_clock_khz = clock_frequency / 1000;
580			dev_warn(&pdev->dev,
581				 "Deprecated usage of the 'clock-frequency' property, please update to 'opencores,ip-clock-frequency'\n");
582		} else {
583			i2c->ip_clock_khz = val / 1000;
584			if (clock_frequency_present)
585				i2c->bus_clock_khz = clock_frequency / 1000;
586		}
587	}
588
589	of_property_read_u32(pdev->dev.of_node, "reg-io-width",
590				&i2c->reg_io_width);
591
592	match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
593	if (match && (long)match->data == TYPE_GRLIB) {
594		dev_dbg(&pdev->dev, "GRLIB variant of i2c-ocores\n");
595		i2c->setreg = oc_setreg_grlib;
596		i2c->getreg = oc_getreg_grlib;
597	}
598
599	return 0;
600}
601#else
602#define ocores_i2c_of_probe(pdev, i2c) -ENODEV
603#endif
604
605static int ocores_i2c_probe(struct platform_device *pdev)
606{
607	struct ocores_i2c *i2c;
608	struct ocores_i2c_platform_data *pdata;
609	const struct of_device_id *match;
610	struct resource *res;
611	int irq;
612	int ret;
613	int i;
614
615	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
616	if (!i2c)
617		return -ENOMEM;
618
619	spin_lock_init(&i2c->process_lock);
620
621	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
622	if (res) {
623		i2c->base = devm_ioremap_resource(&pdev->dev, res);
624		if (IS_ERR(i2c->base))
625			return PTR_ERR(i2c->base);
626	} else {
627		res = platform_get_resource(pdev, IORESOURCE_IO, 0);
628		if (!res)
629			return -EINVAL;
630		i2c->iobase = res->start;
631		if (!devm_request_region(&pdev->dev, res->start,
632					 resource_size(res),
633					 pdev->name)) {
634			dev_err(&pdev->dev, "Can't get I/O resource.\n");
635			return -EBUSY;
636		}
637		i2c->setreg = oc_setreg_io_8;
638		i2c->getreg = oc_getreg_io_8;
639	}
640
641	pdata = dev_get_platdata(&pdev->dev);
642	if (pdata) {
643		i2c->reg_shift = pdata->reg_shift;
644		i2c->reg_io_width = pdata->reg_io_width;
645		i2c->ip_clock_khz = pdata->clock_khz;
646		if (pdata->bus_khz)
647			i2c->bus_clock_khz = pdata->bus_khz;
648		else
649			i2c->bus_clock_khz = 100;
650	} else {
651		ret = ocores_i2c_of_probe(pdev, i2c);
652		if (ret)
653			return ret;
654	}
655
656	if (i2c->reg_io_width == 0)
657		i2c->reg_io_width = 1; /* Set to default value */
658
659	if (!i2c->setreg || !i2c->getreg) {
660		bool be = pdata ? pdata->big_endian :
661			of_device_is_big_endian(pdev->dev.of_node);
662
663		switch (i2c->reg_io_width) {
664		case 1:
665			i2c->setreg = oc_setreg_8;
666			i2c->getreg = oc_getreg_8;
667			break;
668
669		case 2:
670			i2c->setreg = be ? oc_setreg_16be : oc_setreg_16;
671			i2c->getreg = be ? oc_getreg_16be : oc_getreg_16;
672			break;
673
674		case 4:
675			i2c->setreg = be ? oc_setreg_32be : oc_setreg_32;
676			i2c->getreg = be ? oc_getreg_32be : oc_getreg_32;
677			break;
678
679		default:
680			dev_err(&pdev->dev, "Unsupported I/O width (%d)\n",
681				i2c->reg_io_width);
682			ret = -EINVAL;
683			goto err_clk;
684		}
685	}
686
687	init_waitqueue_head(&i2c->wait);
688
689	irq = platform_get_irq(pdev, 0);
690	if (irq == -ENXIO) {
691		ocores_algorithm.master_xfer = ocores_xfer_polling;
692
693		/*
694		 * Set in OCORES_FLAG_BROKEN_IRQ to enable workaround for
695		 * FU540-C000 SoC in polling mode.
696		 */
697		match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
698		if (match && (long)match->data == TYPE_SIFIVE_REV0)
699			i2c->flags |= OCORES_FLAG_BROKEN_IRQ;
700	} else {
701		if (irq < 0)
702			return irq;
703	}
704
705	if (ocores_algorithm.master_xfer != ocores_xfer_polling) {
706		ret = devm_request_any_context_irq(&pdev->dev, irq,
707						   ocores_isr, 0,
708						   pdev->name, i2c);
709		if (ret) {
710			dev_err(&pdev->dev, "Cannot claim IRQ\n");
711			goto err_clk;
712		}
713	}
714
715	ret = ocores_init(&pdev->dev, i2c);
716	if (ret)
717		goto err_clk;
718
719	/* hook up driver to tree */
720	platform_set_drvdata(pdev, i2c);
721	i2c->adap = ocores_adapter;
722	i2c_set_adapdata(&i2c->adap, i2c);
723	i2c->adap.dev.parent = &pdev->dev;
724	i2c->adap.dev.of_node = pdev->dev.of_node;
725
726	/* add i2c adapter to i2c tree */
727	ret = i2c_add_adapter(&i2c->adap);
728	if (ret)
729		goto err_clk;
730
731	/* add in known devices to the bus */
732	if (pdata) {
733		for (i = 0; i < pdata->num_devices; i++)
734			i2c_new_client_device(&i2c->adap, pdata->devices + i);
735	}
736
737	return 0;
738
739err_clk:
740	clk_disable_unprepare(i2c->clk);
741	return ret;
742}
743
744static int ocores_i2c_remove(struct platform_device *pdev)
745{
746	struct ocores_i2c *i2c = platform_get_drvdata(pdev);
747	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
748
749	/* disable i2c logic */
750	ctrl &= ~(OCI2C_CTRL_EN | OCI2C_CTRL_IEN);
751	oc_setreg(i2c, OCI2C_CONTROL, ctrl);
752
753	/* remove adapter & data */
754	i2c_del_adapter(&i2c->adap);
755
756	if (!IS_ERR(i2c->clk))
757		clk_disable_unprepare(i2c->clk);
758
759	return 0;
760}
761
762#ifdef CONFIG_PM_SLEEP
763static int ocores_i2c_suspend(struct device *dev)
764{
765	struct ocores_i2c *i2c = dev_get_drvdata(dev);
766	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
767
768	/* make sure the device is disabled */
769	ctrl &= ~(OCI2C_CTRL_EN | OCI2C_CTRL_IEN);
770	oc_setreg(i2c, OCI2C_CONTROL, ctrl);
771
772	if (!IS_ERR(i2c->clk))
773		clk_disable_unprepare(i2c->clk);
774	return 0;
775}
776
777static int ocores_i2c_resume(struct device *dev)
778{
779	struct ocores_i2c *i2c = dev_get_drvdata(dev);
780
781	if (!IS_ERR(i2c->clk)) {
782		unsigned long rate;
783		int ret = clk_prepare_enable(i2c->clk);
784
785		if (ret) {
786			dev_err(dev,
787				"clk_prepare_enable failed: %d\n", ret);
788			return ret;
789		}
790		rate = clk_get_rate(i2c->clk) / 1000;
791		if (rate)
792			i2c->ip_clock_khz = rate;
793	}
794	return ocores_init(dev, i2c);
795}
796
797static SIMPLE_DEV_PM_OPS(ocores_i2c_pm, ocores_i2c_suspend, ocores_i2c_resume);
798#define OCORES_I2C_PM	(&ocores_i2c_pm)
799#else
800#define OCORES_I2C_PM	NULL
801#endif
802
803static struct platform_driver ocores_i2c_driver = {
804	.probe   = ocores_i2c_probe,
805	.remove  = ocores_i2c_remove,
806	.driver  = {
807		.name = "ocores-i2c",
808		.of_match_table = ocores_i2c_match,
809		.pm = OCORES_I2C_PM,
810	},
811};
812
813module_platform_driver(ocores_i2c_driver);
814
815MODULE_AUTHOR("Peter Korsgaard <peter@korsgaard.com>");
816MODULE_DESCRIPTION("OpenCores I2C bus driver");
817MODULE_LICENSE("GPL");
818MODULE_ALIAS("platform:ocores-i2c");