xref: /linux/drivers/i2c/busses/i2c-imx-lpi2c.c (revision 32786fdc9506aeba98278c1844d4bfb766863832)
1 /*
2  * This is i.MX low power i2c controller driver.
3  *
4  * Copyright 2016 Freescale Semiconductor, Inc.
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version 2
9  * of the License, or (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  */
17 
18 #include <linux/clk.h>
19 #include <linux/completion.h>
20 #include <linux/delay.h>
21 #include <linux/err.h>
22 #include <linux/errno.h>
23 #include <linux/i2c.h>
24 #include <linux/init.h>
25 #include <linux/interrupt.h>
26 #include <linux/io.h>
27 #include <linux/kernel.h>
28 #include <linux/module.h>
29 #include <linux/of.h>
30 #include <linux/of_device.h>
31 #include <linux/platform_device.h>
32 #include <linux/sched.h>
33 #include <linux/slab.h>
34 
35 #define DRIVER_NAME "imx-lpi2c"
36 
37 #define LPI2C_PARAM	0x04	/* i2c RX/TX FIFO size */
38 #define LPI2C_MCR	0x10	/* i2c contrl register */
39 #define LPI2C_MSR	0x14	/* i2c status register */
40 #define LPI2C_MIER	0x18	/* i2c interrupt enable */
41 #define LPI2C_MCFGR0	0x20	/* i2c master configuration */
42 #define LPI2C_MCFGR1	0x24	/* i2c master configuration */
43 #define LPI2C_MCFGR2	0x28	/* i2c master configuration */
44 #define LPI2C_MCFGR3	0x2C	/* i2c master configuration */
45 #define LPI2C_MCCR0	0x48	/* i2c master clk configuration */
46 #define LPI2C_MCCR1	0x50	/* i2c master clk configuration */
47 #define LPI2C_MFCR	0x58	/* i2c master FIFO control */
48 #define LPI2C_MFSR	0x5C	/* i2c master FIFO status */
49 #define LPI2C_MTDR	0x60	/* i2c master TX data register */
50 #define LPI2C_MRDR	0x70	/* i2c master RX data register */
51 
52 /* i2c command */
53 #define TRAN_DATA	0X00
54 #define RECV_DATA	0X01
55 #define GEN_STOP	0X02
56 #define RECV_DISCARD	0X03
57 #define GEN_START	0X04
58 #define START_NACK	0X05
59 #define START_HIGH	0X06
60 #define START_HIGH_NACK	0X07
61 
62 #define MCR_MEN		BIT(0)
63 #define MCR_RST		BIT(1)
64 #define MCR_DOZEN	BIT(2)
65 #define MCR_DBGEN	BIT(3)
66 #define MCR_RTF		BIT(8)
67 #define MCR_RRF		BIT(9)
68 #define MSR_TDF		BIT(0)
69 #define MSR_RDF		BIT(1)
70 #define MSR_SDF		BIT(9)
71 #define MSR_NDF		BIT(10)
72 #define MSR_ALF		BIT(11)
73 #define MSR_MBF		BIT(24)
74 #define MSR_BBF		BIT(25)
75 #define MIER_TDIE	BIT(0)
76 #define MIER_RDIE	BIT(1)
77 #define MIER_SDIE	BIT(9)
78 #define MIER_NDIE	BIT(10)
79 #define MCFGR1_AUTOSTOP	BIT(8)
80 #define MCFGR1_IGNACK	BIT(9)
81 #define MRDR_RXEMPTY	BIT(14)
82 
83 #define I2C_CLK_RATIO	2
84 #define CHUNK_DATA	256
85 
86 #define LPI2C_DEFAULT_RATE	100000
87 #define STARDARD_MAX_BITRATE	400000
88 #define FAST_MAX_BITRATE	1000000
89 #define FAST_PLUS_MAX_BITRATE	3400000
90 #define HIGHSPEED_MAX_BITRATE	5000000
91 
92 enum lpi2c_imx_mode {
93 	STANDARD,	/* 100+Kbps */
94 	FAST,		/* 400+Kbps */
95 	FAST_PLUS,	/* 1.0+Mbps */
96 	HS,		/* 3.4+Mbps */
97 	ULTRA_FAST,	/* 5.0+Mbps */
98 };
99 
100 enum lpi2c_imx_pincfg {
101 	TWO_PIN_OD,
102 	TWO_PIN_OO,
103 	TWO_PIN_PP,
104 	FOUR_PIN_PP,
105 };
106 
107 struct lpi2c_imx_struct {
108 	struct i2c_adapter	adapter;
109 	struct clk		*clk;
110 	void __iomem		*base;
111 	__u8			*rx_buf;
112 	__u8			*tx_buf;
113 	struct completion	complete;
114 	unsigned int		msglen;
115 	unsigned int		delivered;
116 	unsigned int		block_data;
117 	unsigned int		bitrate;
118 	unsigned int		txfifosize;
119 	unsigned int		rxfifosize;
120 	enum lpi2c_imx_mode	mode;
121 };
122 
123 static void lpi2c_imx_intctrl(struct lpi2c_imx_struct *lpi2c_imx,
124 			      unsigned int enable)
125 {
126 	writel(enable, lpi2c_imx->base + LPI2C_MIER);
127 }
128 
129 static int lpi2c_imx_bus_busy(struct lpi2c_imx_struct *lpi2c_imx)
130 {
131 	unsigned long orig_jiffies = jiffies;
132 	unsigned int temp;
133 
134 	while (1) {
135 		temp = readl(lpi2c_imx->base + LPI2C_MSR);
136 
137 		/* check for arbitration lost, clear if set */
138 		if (temp & MSR_ALF) {
139 			writel(temp, lpi2c_imx->base + LPI2C_MSR);
140 			return -EAGAIN;
141 		}
142 
143 		if (temp & (MSR_BBF | MSR_MBF))
144 			break;
145 
146 		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
147 			dev_dbg(&lpi2c_imx->adapter.dev, "bus not work\n");
148 			return -ETIMEDOUT;
149 		}
150 		schedule();
151 	}
152 
153 	return 0;
154 }
155 
156 static void lpi2c_imx_set_mode(struct lpi2c_imx_struct *lpi2c_imx)
157 {
158 	unsigned int bitrate = lpi2c_imx->bitrate;
159 	enum lpi2c_imx_mode mode;
160 
161 	if (bitrate < STARDARD_MAX_BITRATE)
162 		mode = STANDARD;
163 	else if (bitrate < FAST_MAX_BITRATE)
164 		mode = FAST;
165 	else if (bitrate < FAST_PLUS_MAX_BITRATE)
166 		mode = FAST_PLUS;
167 	else if (bitrate < HIGHSPEED_MAX_BITRATE)
168 		mode = HS;
169 	else
170 		mode = ULTRA_FAST;
171 
172 	lpi2c_imx->mode = mode;
173 }
174 
175 static int lpi2c_imx_start(struct lpi2c_imx_struct *lpi2c_imx,
176 			   struct i2c_msg *msgs)
177 {
178 	unsigned int temp;
179 	u8 read;
180 
181 	temp = readl(lpi2c_imx->base + LPI2C_MCR);
182 	temp |= MCR_RRF | MCR_RTF;
183 	writel(temp, lpi2c_imx->base + LPI2C_MCR);
184 	writel(0x7f00, lpi2c_imx->base + LPI2C_MSR);
185 
186 	read = msgs->flags & I2C_M_RD;
187 	temp = (msgs->addr << 1 | read) | (GEN_START << 8);
188 	writel(temp, lpi2c_imx->base + LPI2C_MTDR);
189 
190 	return lpi2c_imx_bus_busy(lpi2c_imx);
191 }
192 
193 static void lpi2c_imx_stop(struct lpi2c_imx_struct *lpi2c_imx)
194 {
195 	unsigned long orig_jiffies = jiffies;
196 	unsigned int temp;
197 
198 	writel(GEN_STOP << 8, lpi2c_imx->base + LPI2C_MTDR);
199 
200 	do {
201 		temp = readl(lpi2c_imx->base + LPI2C_MSR);
202 		if (temp & MSR_SDF)
203 			break;
204 
205 		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
206 			dev_dbg(&lpi2c_imx->adapter.dev, "stop timeout\n");
207 			break;
208 		}
209 		schedule();
210 
211 	} while (1);
212 }
213 
214 /* CLKLO = I2C_CLK_RATIO * CLKHI, SETHOLD = CLKHI, DATAVD = CLKHI/2 */
215 static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx)
216 {
217 	u8 prescale, filt, sethold, clkhi, clklo, datavd;
218 	unsigned int clk_rate, clk_cycle;
219 	enum lpi2c_imx_pincfg pincfg;
220 	unsigned int temp;
221 
222 	lpi2c_imx_set_mode(lpi2c_imx);
223 
224 	clk_rate = clk_get_rate(lpi2c_imx->clk);
225 	if (lpi2c_imx->mode == HS || lpi2c_imx->mode == ULTRA_FAST)
226 		filt = 0;
227 	else
228 		filt = 2;
229 
230 	for (prescale = 0; prescale <= 7; prescale++) {
231 		clk_cycle = clk_rate / ((1 << prescale) * lpi2c_imx->bitrate)
232 			    - 3 - (filt >> 1);
233 		clkhi = (clk_cycle + I2C_CLK_RATIO) / (I2C_CLK_RATIO + 1);
234 		clklo = clk_cycle - clkhi;
235 		if (clklo < 64)
236 			break;
237 	}
238 
239 	if (prescale > 7)
240 		return -EINVAL;
241 
242 	/* set MCFGR1: PINCFG, PRESCALE, IGNACK */
243 	if (lpi2c_imx->mode == ULTRA_FAST)
244 		pincfg = TWO_PIN_OO;
245 	else
246 		pincfg = TWO_PIN_OD;
247 	temp = prescale | pincfg << 24;
248 
249 	if (lpi2c_imx->mode == ULTRA_FAST)
250 		temp |= MCFGR1_IGNACK;
251 
252 	writel(temp, lpi2c_imx->base + LPI2C_MCFGR1);
253 
254 	/* set MCFGR2: FILTSDA, FILTSCL */
255 	temp = (filt << 16) | (filt << 24);
256 	writel(temp, lpi2c_imx->base + LPI2C_MCFGR2);
257 
258 	/* set MCCR: DATAVD, SETHOLD, CLKHI, CLKLO */
259 	sethold = clkhi;
260 	datavd = clkhi >> 1;
261 	temp = datavd << 24 | sethold << 16 | clkhi << 8 | clklo;
262 
263 	if (lpi2c_imx->mode == HS)
264 		writel(temp, lpi2c_imx->base + LPI2C_MCCR1);
265 	else
266 		writel(temp, lpi2c_imx->base + LPI2C_MCCR0);
267 
268 	return 0;
269 }
270 
271 static int lpi2c_imx_master_enable(struct lpi2c_imx_struct *lpi2c_imx)
272 {
273 	unsigned int temp;
274 	int ret;
275 
276 	ret = clk_enable(lpi2c_imx->clk);
277 	if (ret)
278 		return ret;
279 
280 	temp = MCR_RST;
281 	writel(temp, lpi2c_imx->base + LPI2C_MCR);
282 	writel(0, lpi2c_imx->base + LPI2C_MCR);
283 
284 	ret = lpi2c_imx_config(lpi2c_imx);
285 	if (ret)
286 		goto clk_disable;
287 
288 	temp = readl(lpi2c_imx->base + LPI2C_MCR);
289 	temp |= MCR_MEN;
290 	writel(temp, lpi2c_imx->base + LPI2C_MCR);
291 
292 	return 0;
293 
294 clk_disable:
295 	clk_disable(lpi2c_imx->clk);
296 
297 	return ret;
298 }
299 
300 static int lpi2c_imx_master_disable(struct lpi2c_imx_struct *lpi2c_imx)
301 {
302 	u32 temp;
303 
304 	temp = readl(lpi2c_imx->base + LPI2C_MCR);
305 	temp &= ~MCR_MEN;
306 	writel(temp, lpi2c_imx->base + LPI2C_MCR);
307 
308 	clk_disable(lpi2c_imx->clk);
309 
310 	return 0;
311 }
312 
313 static int lpi2c_imx_msg_complete(struct lpi2c_imx_struct *lpi2c_imx)
314 {
315 	unsigned long timeout;
316 
317 	timeout = wait_for_completion_timeout(&lpi2c_imx->complete, HZ);
318 
319 	return timeout ? 0 : -ETIMEDOUT;
320 }
321 
322 static int lpi2c_imx_txfifo_empty(struct lpi2c_imx_struct *lpi2c_imx)
323 {
324 	unsigned long orig_jiffies = jiffies;
325 	u32 txcnt;
326 
327 	do {
328 		txcnt = readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff;
329 
330 		if (readl(lpi2c_imx->base + LPI2C_MSR) & MSR_NDF) {
331 			dev_dbg(&lpi2c_imx->adapter.dev, "NDF detected\n");
332 			return -EIO;
333 		}
334 
335 		if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
336 			dev_dbg(&lpi2c_imx->adapter.dev, "txfifo empty timeout\n");
337 			return -ETIMEDOUT;
338 		}
339 		schedule();
340 
341 	} while (txcnt);
342 
343 	return 0;
344 }
345 
346 static void lpi2c_imx_set_tx_watermark(struct lpi2c_imx_struct *lpi2c_imx)
347 {
348 	writel(lpi2c_imx->txfifosize >> 1, lpi2c_imx->base + LPI2C_MFCR);
349 }
350 
351 static void lpi2c_imx_set_rx_watermark(struct lpi2c_imx_struct *lpi2c_imx)
352 {
353 	unsigned int temp, remaining;
354 
355 	remaining = lpi2c_imx->msglen - lpi2c_imx->delivered;
356 
357 	if (remaining > (lpi2c_imx->rxfifosize >> 1))
358 		temp = lpi2c_imx->rxfifosize >> 1;
359 	else
360 		temp = 0;
361 
362 	writel(temp << 16, lpi2c_imx->base + LPI2C_MFCR);
363 }
364 
365 static void lpi2c_imx_write_txfifo(struct lpi2c_imx_struct *lpi2c_imx)
366 {
367 	unsigned int data, txcnt;
368 
369 	txcnt = readl(lpi2c_imx->base + LPI2C_MFSR) & 0xff;
370 
371 	while (txcnt < lpi2c_imx->txfifosize) {
372 		if (lpi2c_imx->delivered == lpi2c_imx->msglen)
373 			break;
374 
375 		data = lpi2c_imx->tx_buf[lpi2c_imx->delivered++];
376 		writel(data, lpi2c_imx->base + LPI2C_MTDR);
377 		txcnt++;
378 	}
379 
380 	if (lpi2c_imx->delivered < lpi2c_imx->msglen)
381 		lpi2c_imx_intctrl(lpi2c_imx, MIER_TDIE | MIER_NDIE);
382 	else
383 		complete(&lpi2c_imx->complete);
384 }
385 
386 static void lpi2c_imx_read_rxfifo(struct lpi2c_imx_struct *lpi2c_imx)
387 {
388 	unsigned int blocklen, remaining;
389 	unsigned int temp, data;
390 
391 	do {
392 		data = readl(lpi2c_imx->base + LPI2C_MRDR);
393 		if (data & MRDR_RXEMPTY)
394 			break;
395 
396 		lpi2c_imx->rx_buf[lpi2c_imx->delivered++] = data & 0xff;
397 	} while (1);
398 
399 	/*
400 	 * First byte is the length of remaining packet in the SMBus block
401 	 * data read. Add it to msgs->len.
402 	 */
403 	if (lpi2c_imx->block_data) {
404 		blocklen = lpi2c_imx->rx_buf[0];
405 		lpi2c_imx->msglen += blocklen;
406 	}
407 
408 	remaining = lpi2c_imx->msglen - lpi2c_imx->delivered;
409 
410 	if (!remaining) {
411 		complete(&lpi2c_imx->complete);
412 		return;
413 	}
414 
415 	/* not finished, still waiting for rx data */
416 	lpi2c_imx_set_rx_watermark(lpi2c_imx);
417 
418 	/* multiple receive commands */
419 	if (lpi2c_imx->block_data) {
420 		lpi2c_imx->block_data = 0;
421 		temp = remaining;
422 		temp |= (RECV_DATA << 8);
423 		writel(temp, lpi2c_imx->base + LPI2C_MTDR);
424 	} else if (!(lpi2c_imx->delivered & 0xff)) {
425 		temp = (remaining > CHUNK_DATA ? CHUNK_DATA : remaining) - 1;
426 		temp |= (RECV_DATA << 8);
427 		writel(temp, lpi2c_imx->base + LPI2C_MTDR);
428 	}
429 
430 	lpi2c_imx_intctrl(lpi2c_imx, MIER_RDIE);
431 }
432 
433 static void lpi2c_imx_write(struct lpi2c_imx_struct *lpi2c_imx,
434 			    struct i2c_msg *msgs)
435 {
436 	lpi2c_imx->tx_buf = msgs->buf;
437 	lpi2c_imx_set_tx_watermark(lpi2c_imx);
438 	lpi2c_imx_write_txfifo(lpi2c_imx);
439 }
440 
441 static void lpi2c_imx_read(struct lpi2c_imx_struct *lpi2c_imx,
442 			   struct i2c_msg *msgs)
443 {
444 	unsigned int temp;
445 
446 	lpi2c_imx->rx_buf = msgs->buf;
447 	lpi2c_imx->block_data = msgs->flags & I2C_M_RECV_LEN;
448 
449 	lpi2c_imx_set_rx_watermark(lpi2c_imx);
450 	temp = msgs->len > CHUNK_DATA ? CHUNK_DATA - 1 : msgs->len - 1;
451 	temp |= (RECV_DATA << 8);
452 	writel(temp, lpi2c_imx->base + LPI2C_MTDR);
453 
454 	lpi2c_imx_intctrl(lpi2c_imx, MIER_RDIE | MIER_NDIE);
455 }
456 
457 static int lpi2c_imx_xfer(struct i2c_adapter *adapter,
458 			  struct i2c_msg *msgs, int num)
459 {
460 	struct lpi2c_imx_struct *lpi2c_imx = i2c_get_adapdata(adapter);
461 	unsigned int temp;
462 	int i, result;
463 
464 	result = lpi2c_imx_master_enable(lpi2c_imx);
465 	if (result)
466 		return result;
467 
468 	for (i = 0; i < num; i++) {
469 		result = lpi2c_imx_start(lpi2c_imx, &msgs[i]);
470 		if (result)
471 			goto disable;
472 
473 		/* quick smbus */
474 		if (num == 1 && msgs[0].len == 0)
475 			goto stop;
476 
477 		lpi2c_imx->delivered = 0;
478 		lpi2c_imx->msglen = msgs[i].len;
479 		init_completion(&lpi2c_imx->complete);
480 
481 		if (msgs[i].flags & I2C_M_RD)
482 			lpi2c_imx_read(lpi2c_imx, &msgs[i]);
483 		else
484 			lpi2c_imx_write(lpi2c_imx, &msgs[i]);
485 
486 		result = lpi2c_imx_msg_complete(lpi2c_imx);
487 		if (result)
488 			goto stop;
489 
490 		if (!(msgs[i].flags & I2C_M_RD)) {
491 			result = lpi2c_imx_txfifo_empty(lpi2c_imx);
492 			if (result)
493 				goto stop;
494 		}
495 	}
496 
497 stop:
498 	lpi2c_imx_stop(lpi2c_imx);
499 
500 	temp = readl(lpi2c_imx->base + LPI2C_MSR);
501 	if ((temp & MSR_NDF) && !result)
502 		result = -EIO;
503 
504 disable:
505 	lpi2c_imx_master_disable(lpi2c_imx);
506 
507 	dev_dbg(&lpi2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
508 		(result < 0) ? "error" : "success msg",
509 		(result < 0) ? result : num);
510 
511 	return (result < 0) ? result : num;
512 }
513 
514 static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
515 {
516 	struct lpi2c_imx_struct *lpi2c_imx = dev_id;
517 	unsigned int temp;
518 
519 	lpi2c_imx_intctrl(lpi2c_imx, 0);
520 	temp = readl(lpi2c_imx->base + LPI2C_MSR);
521 
522 	if (temp & MSR_RDF)
523 		lpi2c_imx_read_rxfifo(lpi2c_imx);
524 
525 	if (temp & MSR_TDF)
526 		lpi2c_imx_write_txfifo(lpi2c_imx);
527 
528 	if (temp & MSR_NDF)
529 		complete(&lpi2c_imx->complete);
530 
531 	return IRQ_HANDLED;
532 }
533 
534 static u32 lpi2c_imx_func(struct i2c_adapter *adapter)
535 {
536 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
537 		I2C_FUNC_SMBUS_READ_BLOCK_DATA;
538 }
539 
540 static struct i2c_algorithm lpi2c_imx_algo = {
541 	.master_xfer	= lpi2c_imx_xfer,
542 	.functionality	= lpi2c_imx_func,
543 };
544 
545 static const struct of_device_id lpi2c_imx_of_match[] = {
546 	{ .compatible = "fsl,imx7ulp-lpi2c" },
547 	{ .compatible = "fsl,imx8dv-lpi2c" },
548 	{ },
549 };
550 MODULE_DEVICE_TABLE(of, lpi2c_imx_of_match);
551 
552 static int lpi2c_imx_probe(struct platform_device *pdev)
553 {
554 	struct lpi2c_imx_struct *lpi2c_imx;
555 	struct resource *res;
556 	unsigned int temp;
557 	int irq, ret;
558 
559 	lpi2c_imx = devm_kzalloc(&pdev->dev, sizeof(*lpi2c_imx), GFP_KERNEL);
560 	if (!lpi2c_imx)
561 		return -ENOMEM;
562 
563 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
564 	lpi2c_imx->base = devm_ioremap_resource(&pdev->dev, res);
565 	if (IS_ERR(lpi2c_imx->base))
566 		return PTR_ERR(lpi2c_imx->base);
567 
568 	irq = platform_get_irq(pdev, 0);
569 	if (irq < 0) {
570 		dev_err(&pdev->dev, "can't get irq number\n");
571 		return irq;
572 	}
573 
574 	lpi2c_imx->adapter.owner	= THIS_MODULE;
575 	lpi2c_imx->adapter.algo		= &lpi2c_imx_algo;
576 	lpi2c_imx->adapter.dev.parent	= &pdev->dev;
577 	lpi2c_imx->adapter.dev.of_node	= pdev->dev.of_node;
578 	strlcpy(lpi2c_imx->adapter.name, pdev->name,
579 		sizeof(lpi2c_imx->adapter.name));
580 
581 	lpi2c_imx->clk = devm_clk_get(&pdev->dev, NULL);
582 	if (IS_ERR(lpi2c_imx->clk)) {
583 		dev_err(&pdev->dev, "can't get I2C peripheral clock\n");
584 		return PTR_ERR(lpi2c_imx->clk);
585 	}
586 
587 	ret = of_property_read_u32(pdev->dev.of_node,
588 				   "clock-frequency", &lpi2c_imx->bitrate);
589 	if (ret)
590 		lpi2c_imx->bitrate = LPI2C_DEFAULT_RATE;
591 
592 	ret = devm_request_irq(&pdev->dev, irq, lpi2c_imx_isr, 0,
593 			       pdev->name, lpi2c_imx);
594 	if (ret) {
595 		dev_err(&pdev->dev, "can't claim irq %d\n", irq);
596 		return ret;
597 	}
598 
599 	i2c_set_adapdata(&lpi2c_imx->adapter, lpi2c_imx);
600 	platform_set_drvdata(pdev, lpi2c_imx);
601 
602 	ret = clk_prepare_enable(lpi2c_imx->clk);
603 	if (ret) {
604 		dev_err(&pdev->dev, "clk enable failed %d\n", ret);
605 		return ret;
606 	}
607 
608 	temp = readl(lpi2c_imx->base + LPI2C_PARAM);
609 	lpi2c_imx->txfifosize = 1 << (temp & 0x0f);
610 	lpi2c_imx->rxfifosize = 1 << ((temp >> 8) & 0x0f);
611 
612 	clk_disable(lpi2c_imx->clk);
613 
614 	ret = i2c_add_adapter(&lpi2c_imx->adapter);
615 	if (ret)
616 		goto clk_unprepare;
617 
618 	dev_info(&lpi2c_imx->adapter.dev, "LPI2C adapter registered\n");
619 
620 	return 0;
621 
622 clk_unprepare:
623 	clk_unprepare(lpi2c_imx->clk);
624 
625 	return ret;
626 }
627 
628 static int lpi2c_imx_remove(struct platform_device *pdev)
629 {
630 	struct lpi2c_imx_struct *lpi2c_imx = platform_get_drvdata(pdev);
631 
632 	i2c_del_adapter(&lpi2c_imx->adapter);
633 
634 	clk_unprepare(lpi2c_imx->clk);
635 
636 	return 0;
637 }
638 
639 static struct platform_driver lpi2c_imx_driver = {
640 	.probe = lpi2c_imx_probe,
641 	.remove = lpi2c_imx_remove,
642 	.driver = {
643 		.name = DRIVER_NAME,
644 		.of_match_table = lpi2c_imx_of_match,
645 	},
646 };
647 
648 module_platform_driver(lpi2c_imx_driver);
649 
650 MODULE_AUTHOR("Gao Pan <pandy.gao@nxp.com>");
651 MODULE_DESCRIPTION("I2C adapter driver for LPI2C bus");
652 MODULE_LICENSE("GPL");
653