xref: /linux/drivers/i2c/busses/i2c-synquacer.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2012 FUJITSU SEMICONDUCTOR LIMITED
4  */
5 
6 #include <linux/acpi.h>
7 #include <linux/clk.h>
8 #include <linux/delay.h>
9 #include <linux/device.h>
10 #include <linux/err.h>
11 #include <linux/errno.h>
12 #include <linux/i2c.h>
13 #include <linux/interrupt.h>
14 #include <linux/io.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/platform_device.h>
18 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <linux/spinlock.h>
21 
22 #define WAIT_PCLK(n, rate)	\
23 	ndelay(DIV_ROUND_UP(DIV_ROUND_UP(1000000000, rate), n) + 10)
24 
25 /* I2C register address definitions */
26 #define SYNQUACER_I2C_REG_BSR		(0x00 << 2) // Bus Status
27 #define SYNQUACER_I2C_REG_BCR		(0x01 << 2) // Bus Control
28 #define SYNQUACER_I2C_REG_CCR		(0x02 << 2) // Clock Control
29 #define SYNQUACER_I2C_REG_ADR		(0x03 << 2) // Address
30 #define SYNQUACER_I2C_REG_DAR		(0x04 << 2) // Data
31 #define SYNQUACER_I2C_REG_CSR		(0x05 << 2) // Expansion CS
32 #define SYNQUACER_I2C_REG_FSR		(0x06 << 2) // Bus Clock Freq
33 #define SYNQUACER_I2C_REG_BC2R		(0x07 << 2) // Bus Control 2
34 
35 /* I2C register bit definitions */
36 #define SYNQUACER_I2C_BSR_FBT		BIT(0)	// First Byte Transfer
37 #define SYNQUACER_I2C_BSR_GCA		BIT(1)	// General Call Address
38 #define SYNQUACER_I2C_BSR_AAS		BIT(2)	// Address as Slave
39 #define SYNQUACER_I2C_BSR_TRX		BIT(3)	// Transfer/Receive
40 #define SYNQUACER_I2C_BSR_LRB		BIT(4)	// Last Received Bit
41 #define SYNQUACER_I2C_BSR_AL		BIT(5)	// Arbitration Lost
42 #define SYNQUACER_I2C_BSR_RSC		BIT(6)	// Repeated Start Cond.
43 #define SYNQUACER_I2C_BSR_BB		BIT(7)	// Bus Busy
44 
45 #define SYNQUACER_I2C_BCR_INT		BIT(0)	// Interrupt
46 #define SYNQUACER_I2C_BCR_INTE		BIT(1)	// Interrupt Enable
47 #define SYNQUACER_I2C_BCR_GCAA		BIT(2)	// Gen. Call Access Ack.
48 #define SYNQUACER_I2C_BCR_ACK		BIT(3)	// Acknowledge
49 #define SYNQUACER_I2C_BCR_MSS		BIT(4)	// Master Slave Select
50 #define SYNQUACER_I2C_BCR_SCC		BIT(5)	// Start Condition Cont.
51 #define SYNQUACER_I2C_BCR_BEIE		BIT(6)	// Bus Error Int Enable
52 #define SYNQUACER_I2C_BCR_BER		BIT(7)	// Bus Error
53 
54 #define SYNQUACER_I2C_CCR_CS_MASK	(0x1f)	// CCR Clock Period Sel.
55 #define SYNQUACER_I2C_CCR_EN		BIT(5)	// Enable
56 #define SYNQUACER_I2C_CCR_FM		BIT(6)	// Speed Mode Select
57 
58 #define SYNQUACER_I2C_CSR_CS_MASK	(0x3f)	// CSR Clock Period Sel.
59 
60 #define SYNQUACER_I2C_BC2R_SCLL		BIT(0)	// SCL Low Drive
61 #define SYNQUACER_I2C_BC2R_SDAL		BIT(1)	// SDA Low Drive
62 #define SYNQUACER_I2C_BC2R_SCLS		BIT(4)	// SCL Status
63 #define SYNQUACER_I2C_BC2R_SDAS		BIT(5)	// SDA Status
64 
65 /* PCLK frequency */
66 #define SYNQUACER_I2C_BUS_CLK_FR(rate)	(((rate) / 20000000) + 1)
67 
68 /* STANDARD MODE frequency */
69 #define SYNQUACER_I2C_CLK_MASTER_STD(rate)			\
70 	DIV_ROUND_UP(DIV_ROUND_UP((rate), I2C_MAX_STANDARD_MODE_FREQ) - 2, 2)
71 /* FAST MODE frequency */
72 #define SYNQUACER_I2C_CLK_MASTER_FAST(rate)			\
73 	DIV_ROUND_UP((DIV_ROUND_UP((rate), I2C_MAX_FAST_MODE_FREQ) - 2) * 2, 3)
74 
75 /* (clkrate <= 18000000) */
76 /* calculate the value of CS bits in CCR register on standard mode */
77 #define SYNQUACER_I2C_CCR_CS_STD_MAX_18M(rate)			\
78 	   ((SYNQUACER_I2C_CLK_MASTER_STD(rate) - 65)		\
79 					& SYNQUACER_I2C_CCR_CS_MASK)
80 
81 /* calculate the value of CS bits in CSR register on standard mode */
82 #define SYNQUACER_I2C_CSR_CS_STD_MAX_18M(rate)		0x00
83 
84 /* calculate the value of CS bits in CCR register on fast mode */
85 #define SYNQUACER_I2C_CCR_CS_FAST_MAX_18M(rate)			\
86 	   ((SYNQUACER_I2C_CLK_MASTER_FAST(rate) - 1)		\
87 					& SYNQUACER_I2C_CCR_CS_MASK)
88 
89 /* calculate the value of CS bits in CSR register on fast mode */
90 #define SYNQUACER_I2C_CSR_CS_FAST_MAX_18M(rate)		0x00
91 
92 /* (clkrate > 18000000) */
93 /* calculate the value of CS bits in CCR register on standard mode */
94 #define SYNQUACER_I2C_CCR_CS_STD_MIN_18M(rate)			\
95 	   ((SYNQUACER_I2C_CLK_MASTER_STD(rate) - 1)		\
96 					& SYNQUACER_I2C_CCR_CS_MASK)
97 
98 /* calculate the value of CS bits in CSR register on standard mode */
99 #define SYNQUACER_I2C_CSR_CS_STD_MIN_18M(rate)			\
100 	   (((SYNQUACER_I2C_CLK_MASTER_STD(rate) - 1) >> 5)	\
101 					& SYNQUACER_I2C_CSR_CS_MASK)
102 
103 /* calculate the value of CS bits in CCR register on fast mode */
104 #define SYNQUACER_I2C_CCR_CS_FAST_MIN_18M(rate)			\
105 	   ((SYNQUACER_I2C_CLK_MASTER_FAST(rate) - 1)		\
106 					& SYNQUACER_I2C_CCR_CS_MASK)
107 
108 /* calculate the value of CS bits in CSR register on fast mode */
109 #define SYNQUACER_I2C_CSR_CS_FAST_MIN_18M(rate)			\
110 	   (((SYNQUACER_I2C_CLK_MASTER_FAST(rate) - 1) >> 5)	\
111 					& SYNQUACER_I2C_CSR_CS_MASK)
112 
113 /* min I2C clock frequency 14M */
114 #define SYNQUACER_I2C_MIN_CLK_RATE	(14 * 1000000)
115 /* max I2C clock frequency 200M */
116 #define SYNQUACER_I2C_MAX_CLK_RATE	(200 * 1000000)
117 /* I2C clock frequency 18M */
118 #define SYNQUACER_I2C_CLK_RATE_18M	(18 * 1000000)
119 
120 #define SYNQUACER_I2C_SPEED_FM		400	// Fast Mode
121 #define SYNQUACER_I2C_SPEED_SM		100	// Standard Mode
122 
123 enum i2c_state {
124 	STATE_IDLE,
125 	STATE_START,
126 	STATE_READ,
127 	STATE_WRITE
128 };
129 
130 struct synquacer_i2c {
131 	struct completion	completion;
132 
133 	struct i2c_msg		*msg;
134 	u32			msg_num;
135 	u32			msg_idx;
136 	u32			msg_ptr;
137 
138 	int			irq;
139 	struct device		*dev;
140 	void __iomem		*base;
141 	u32			pclkrate;
142 	u32			speed_khz;
143 	u32			timeout_ms;
144 	enum i2c_state		state;
145 	struct i2c_adapter	adapter;
146 };
147 
148 static inline int is_lastmsg(struct synquacer_i2c *i2c)
149 {
150 	return i2c->msg_idx >= (i2c->msg_num - 1);
151 }
152 
153 static inline int is_msglast(struct synquacer_i2c *i2c)
154 {
155 	return i2c->msg_ptr == (i2c->msg->len - 1);
156 }
157 
158 static inline int is_msgend(struct synquacer_i2c *i2c)
159 {
160 	return i2c->msg_ptr >= i2c->msg->len;
161 }
162 
163 static inline unsigned long calc_timeout_ms(struct synquacer_i2c *i2c,
164 					    struct i2c_msg *msgs,
165 					    int num)
166 {
167 	unsigned long bit_count = 0;
168 	int i;
169 
170 	for (i = 0; i < num; i++, msgs++)
171 		bit_count += msgs->len;
172 
173 	return DIV_ROUND_UP((bit_count * 9 + num * 10) * 3, 200) + 10;
174 }
175 
176 static void synquacer_i2c_stop(struct synquacer_i2c *i2c, int ret)
177 {
178 	/*
179 	 * clear IRQ (INT=0, BER=0)
180 	 * set Stop Condition (MSS=0)
181 	 * Interrupt Disable
182 	 */
183 	writeb(0, i2c->base + SYNQUACER_I2C_REG_BCR);
184 
185 	i2c->state = STATE_IDLE;
186 
187 	i2c->msg_ptr = 0;
188 	i2c->msg = NULL;
189 	i2c->msg_idx++;
190 	i2c->msg_num = 0;
191 	if (ret)
192 		i2c->msg_idx = ret;
193 
194 	complete(&i2c->completion);
195 }
196 
197 static void synquacer_i2c_hw_init(struct synquacer_i2c *i2c)
198 {
199 	unsigned char ccr_cs, csr_cs;
200 	u32 rt = i2c->pclkrate;
201 
202 	/* Set own Address */
203 	writeb(0, i2c->base + SYNQUACER_I2C_REG_ADR);
204 
205 	/* Set PCLK frequency */
206 	writeb(SYNQUACER_I2C_BUS_CLK_FR(i2c->pclkrate),
207 	       i2c->base + SYNQUACER_I2C_REG_FSR);
208 
209 	switch (i2c->speed_khz) {
210 	case SYNQUACER_I2C_SPEED_FM:
211 		if (i2c->pclkrate <= SYNQUACER_I2C_CLK_RATE_18M) {
212 			ccr_cs = SYNQUACER_I2C_CCR_CS_FAST_MAX_18M(rt);
213 			csr_cs = SYNQUACER_I2C_CSR_CS_FAST_MAX_18M(rt);
214 		} else {
215 			ccr_cs = SYNQUACER_I2C_CCR_CS_FAST_MIN_18M(rt);
216 			csr_cs = SYNQUACER_I2C_CSR_CS_FAST_MIN_18M(rt);
217 		}
218 
219 		/* Set Clock and enable, Set fast mode */
220 		writeb(ccr_cs | SYNQUACER_I2C_CCR_FM |
221 		       SYNQUACER_I2C_CCR_EN,
222 		       i2c->base + SYNQUACER_I2C_REG_CCR);
223 		writeb(csr_cs, i2c->base + SYNQUACER_I2C_REG_CSR);
224 		break;
225 	case SYNQUACER_I2C_SPEED_SM:
226 		if (i2c->pclkrate <= SYNQUACER_I2C_CLK_RATE_18M) {
227 			ccr_cs = SYNQUACER_I2C_CCR_CS_STD_MAX_18M(rt);
228 			csr_cs = SYNQUACER_I2C_CSR_CS_STD_MAX_18M(rt);
229 		} else {
230 			ccr_cs = SYNQUACER_I2C_CCR_CS_STD_MIN_18M(rt);
231 			csr_cs = SYNQUACER_I2C_CSR_CS_STD_MIN_18M(rt);
232 		}
233 
234 		/* Set Clock and enable, Set standard mode */
235 		writeb(ccr_cs | SYNQUACER_I2C_CCR_EN,
236 		      i2c->base + SYNQUACER_I2C_REG_CCR);
237 		writeb(csr_cs, i2c->base + SYNQUACER_I2C_REG_CSR);
238 		break;
239 	default:
240 		WARN_ON(1);
241 	}
242 
243 	/* clear IRQ (INT=0, BER=0), Interrupt Disable */
244 	writeb(0, i2c->base + SYNQUACER_I2C_REG_BCR);
245 	writeb(0, i2c->base + SYNQUACER_I2C_REG_BC2R);
246 }
247 
248 static void synquacer_i2c_hw_reset(struct synquacer_i2c *i2c)
249 {
250 	/* Disable clock */
251 	writeb(0, i2c->base + SYNQUACER_I2C_REG_CCR);
252 	writeb(0, i2c->base + SYNQUACER_I2C_REG_CSR);
253 
254 	WAIT_PCLK(100, i2c->pclkrate);
255 }
256 
257 static int synquacer_i2c_master_start(struct synquacer_i2c *i2c,
258 				      struct i2c_msg *pmsg)
259 {
260 	unsigned char bsr, bcr;
261 
262 	writeb(i2c_8bit_addr_from_msg(pmsg), i2c->base + SYNQUACER_I2C_REG_DAR);
263 
264 	dev_dbg(i2c->dev, "slave:0x%02x\n", pmsg->addr);
265 
266 	/* Generate Start Condition */
267 	bsr = readb(i2c->base + SYNQUACER_I2C_REG_BSR);
268 	bcr = readb(i2c->base + SYNQUACER_I2C_REG_BCR);
269 	dev_dbg(i2c->dev, "bsr:0x%02x, bcr:0x%02x\n", bsr, bcr);
270 
271 	if ((bsr & SYNQUACER_I2C_BSR_BB) &&
272 	    !(bcr & SYNQUACER_I2C_BCR_MSS)) {
273 		dev_dbg(i2c->dev, "bus is busy");
274 		return -EBUSY;
275 	}
276 
277 	if (bsr & SYNQUACER_I2C_BSR_BB) { /* Bus is busy */
278 		dev_dbg(i2c->dev, "Continuous Start");
279 		writeb(bcr | SYNQUACER_I2C_BCR_SCC,
280 		       i2c->base + SYNQUACER_I2C_REG_BCR);
281 	} else {
282 		if (bcr & SYNQUACER_I2C_BCR_MSS) {
283 			dev_dbg(i2c->dev, "not in master mode");
284 			return -EAGAIN;
285 		}
286 		dev_dbg(i2c->dev, "Start Condition");
287 		/* Start Condition + Enable Interrupts */
288 		writeb(bcr | SYNQUACER_I2C_BCR_MSS |
289 		       SYNQUACER_I2C_BCR_INTE | SYNQUACER_I2C_BCR_BEIE,
290 		       i2c->base + SYNQUACER_I2C_REG_BCR);
291 	}
292 
293 	WAIT_PCLK(10, i2c->pclkrate);
294 
295 	/* get BSR & BCR registers */
296 	bsr = readb(i2c->base + SYNQUACER_I2C_REG_BSR);
297 	bcr = readb(i2c->base + SYNQUACER_I2C_REG_BCR);
298 	dev_dbg(i2c->dev, "bsr:0x%02x, bcr:0x%02x\n", bsr, bcr);
299 
300 	if ((bsr & SYNQUACER_I2C_BSR_AL) ||
301 	    !(bcr & SYNQUACER_I2C_BCR_MSS)) {
302 		dev_dbg(i2c->dev, "arbitration lost\n");
303 		return -EAGAIN;
304 	}
305 
306 	return 0;
307 }
308 
309 static int synquacer_i2c_doxfer(struct synquacer_i2c *i2c,
310 				struct i2c_msg *msgs, int num)
311 {
312 	unsigned char bsr;
313 	unsigned long time_left;
314 	int ret;
315 
316 	synquacer_i2c_hw_init(i2c);
317 	bsr = readb(i2c->base + SYNQUACER_I2C_REG_BSR);
318 	if (bsr & SYNQUACER_I2C_BSR_BB) {
319 		dev_err(i2c->dev, "cannot get bus (bus busy)\n");
320 		return -EBUSY;
321 	}
322 
323 	reinit_completion(&i2c->completion);
324 
325 	i2c->msg = msgs;
326 	i2c->msg_num = num;
327 	i2c->msg_ptr = 0;
328 	i2c->msg_idx = 0;
329 	i2c->state = STATE_START;
330 
331 	ret = synquacer_i2c_master_start(i2c, i2c->msg);
332 	if (ret < 0) {
333 		dev_dbg(i2c->dev, "Address failed: (%d)\n", ret);
334 		return ret;
335 	}
336 
337 	time_left = wait_for_completion_timeout(&i2c->completion,
338 						msecs_to_jiffies(i2c->timeout_ms));
339 	if (time_left == 0) {
340 		dev_dbg(i2c->dev, "timeout\n");
341 		return -EAGAIN;
342 	}
343 
344 	ret = i2c->msg_idx;
345 	if (ret != num) {
346 		dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
347 		return -EAGAIN;
348 	}
349 
350 	/* wait 2 clock periods to ensure the stop has been through the bus */
351 	udelay(DIV_ROUND_UP(2 * 1000, i2c->speed_khz));
352 
353 	return ret;
354 }
355 
356 static irqreturn_t synquacer_i2c_isr(int irq, void *dev_id)
357 {
358 	struct synquacer_i2c *i2c = dev_id;
359 
360 	unsigned char byte;
361 	unsigned char bsr, bcr;
362 	int ret;
363 
364 	bcr = readb(i2c->base + SYNQUACER_I2C_REG_BCR);
365 	bsr = readb(i2c->base + SYNQUACER_I2C_REG_BSR);
366 	dev_dbg(i2c->dev, "bsr:0x%02x, bcr:0x%02x\n", bsr, bcr);
367 
368 	if (bcr & SYNQUACER_I2C_BCR_BER) {
369 		dev_err(i2c->dev, "bus error\n");
370 		synquacer_i2c_stop(i2c, -EAGAIN);
371 		goto out;
372 	}
373 	if ((bsr & SYNQUACER_I2C_BSR_AL) ||
374 	    !(bcr & SYNQUACER_I2C_BCR_MSS)) {
375 		dev_dbg(i2c->dev, "arbitration lost\n");
376 		synquacer_i2c_stop(i2c, -EAGAIN);
377 		goto out;
378 	}
379 
380 	switch (i2c->state) {
381 	case STATE_START:
382 		if (bsr & SYNQUACER_I2C_BSR_LRB) {
383 			dev_dbg(i2c->dev, "ack was not received\n");
384 			synquacer_i2c_stop(i2c, -EAGAIN);
385 			goto out;
386 		}
387 
388 		if (i2c->msg->flags & I2C_M_RD)
389 			i2c->state = STATE_READ;
390 		else
391 			i2c->state = STATE_WRITE;
392 
393 		if (is_lastmsg(i2c) && i2c->msg->len == 0) {
394 			synquacer_i2c_stop(i2c, 0);
395 			goto out;
396 		}
397 
398 		if (i2c->state == STATE_READ)
399 			goto prepare_read;
400 		fallthrough;
401 
402 	case STATE_WRITE:
403 		if (bsr & SYNQUACER_I2C_BSR_LRB) {
404 			dev_dbg(i2c->dev, "WRITE: No Ack\n");
405 			synquacer_i2c_stop(i2c, -EAGAIN);
406 			goto out;
407 		}
408 
409 		if (!is_msgend(i2c)) {
410 			writeb(i2c->msg->buf[i2c->msg_ptr++],
411 			       i2c->base + SYNQUACER_I2C_REG_DAR);
412 
413 			/* clear IRQ, and continue */
414 			writeb(SYNQUACER_I2C_BCR_BEIE |
415 			       SYNQUACER_I2C_BCR_MSS |
416 			       SYNQUACER_I2C_BCR_INTE,
417 			       i2c->base + SYNQUACER_I2C_REG_BCR);
418 			break;
419 		}
420 		if (is_lastmsg(i2c)) {
421 			synquacer_i2c_stop(i2c, 0);
422 			break;
423 		}
424 		dev_dbg(i2c->dev, "WRITE: Next Message\n");
425 
426 		i2c->msg_ptr = 0;
427 		i2c->msg_idx++;
428 		i2c->msg++;
429 
430 		/* send the new start */
431 		ret = synquacer_i2c_master_start(i2c, i2c->msg);
432 		if (ret < 0) {
433 			dev_dbg(i2c->dev, "restart error (%d)\n", ret);
434 			synquacer_i2c_stop(i2c, -EAGAIN);
435 			break;
436 		}
437 		i2c->state = STATE_START;
438 		break;
439 
440 	case STATE_READ:
441 		byte = readb(i2c->base + SYNQUACER_I2C_REG_DAR);
442 		if (!(bsr & SYNQUACER_I2C_BSR_FBT)) /* data */
443 			i2c->msg->buf[i2c->msg_ptr++] = byte;
444 		else /* address */
445 			dev_dbg(i2c->dev, "address:0x%02x. ignore it.\n", byte);
446 
447 prepare_read:
448 		if (is_msglast(i2c)) {
449 			writeb(SYNQUACER_I2C_BCR_MSS |
450 			       SYNQUACER_I2C_BCR_BEIE |
451 			       SYNQUACER_I2C_BCR_INTE,
452 			       i2c->base + SYNQUACER_I2C_REG_BCR);
453 			break;
454 		}
455 		if (!is_msgend(i2c)) {
456 			writeb(SYNQUACER_I2C_BCR_MSS |
457 			       SYNQUACER_I2C_BCR_BEIE |
458 			       SYNQUACER_I2C_BCR_INTE |
459 			       SYNQUACER_I2C_BCR_ACK,
460 			       i2c->base + SYNQUACER_I2C_REG_BCR);
461 			break;
462 		}
463 		if (is_lastmsg(i2c)) {
464 			/* last message, send stop and complete */
465 			dev_dbg(i2c->dev, "READ: Send Stop\n");
466 			synquacer_i2c_stop(i2c, 0);
467 			break;
468 		}
469 		dev_dbg(i2c->dev, "READ: Next Transfer\n");
470 
471 		i2c->msg_ptr = 0;
472 		i2c->msg_idx++;
473 		i2c->msg++;
474 
475 		ret = synquacer_i2c_master_start(i2c, i2c->msg);
476 		if (ret < 0) {
477 			dev_dbg(i2c->dev, "restart error (%d)\n", ret);
478 			synquacer_i2c_stop(i2c, -EAGAIN);
479 		} else {
480 			i2c->state = STATE_START;
481 		}
482 		break;
483 	default:
484 		dev_err(i2c->dev, "called in err STATE (%d)\n", i2c->state);
485 		break;
486 	}
487 
488 out:
489 	WAIT_PCLK(10, i2c->pclkrate);
490 	return IRQ_HANDLED;
491 }
492 
493 static int synquacer_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
494 			      int num)
495 {
496 	struct synquacer_i2c *i2c;
497 	int retry;
498 	int ret;
499 
500 	i2c = i2c_get_adapdata(adap);
501 	i2c->timeout_ms = calc_timeout_ms(i2c, msgs, num);
502 
503 	dev_dbg(i2c->dev, "calculated timeout %d ms\n", i2c->timeout_ms);
504 
505 	for (retry = 0; retry <= adap->retries; retry++) {
506 		ret = synquacer_i2c_doxfer(i2c, msgs, num);
507 		if (ret != -EAGAIN)
508 			return ret;
509 
510 		dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
511 
512 		synquacer_i2c_hw_reset(i2c);
513 	}
514 	return -EIO;
515 }
516 
517 static u32 synquacer_i2c_functionality(struct i2c_adapter *adap)
518 {
519 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
520 }
521 
522 static const struct i2c_algorithm synquacer_i2c_algo = {
523 	.master_xfer	= synquacer_i2c_xfer,
524 	.functionality	= synquacer_i2c_functionality,
525 };
526 
527 static const struct i2c_adapter synquacer_i2c_ops = {
528 	.owner		= THIS_MODULE,
529 	.name		= "synquacer_i2c-adapter",
530 	.algo		= &synquacer_i2c_algo,
531 	.retries	= 5,
532 };
533 
534 static int synquacer_i2c_probe(struct platform_device *pdev)
535 {
536 	struct synquacer_i2c *i2c;
537 	struct clk *pclk;
538 	u32 bus_speed;
539 	int ret;
540 
541 	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
542 	if (!i2c)
543 		return -ENOMEM;
544 
545 	bus_speed = i2c_acpi_find_bus_speed(&pdev->dev);
546 	if (!bus_speed)
547 		device_property_read_u32(&pdev->dev, "clock-frequency",
548 					 &bus_speed);
549 
550 	device_property_read_u32(&pdev->dev, "socionext,pclk-rate",
551 				 &i2c->pclkrate);
552 
553 	pclk = devm_clk_get_optional_enabled(&pdev->dev, "pclk");
554 	if (IS_ERR(pclk))
555 		return dev_err_probe(&pdev->dev, PTR_ERR(pclk),
556 				     "failed to get and enable clock\n");
557 
558 	if (pclk)
559 		i2c->pclkrate = clk_get_rate(pclk);
560 
561 	if (i2c->pclkrate < SYNQUACER_I2C_MIN_CLK_RATE ||
562 	    i2c->pclkrate > SYNQUACER_I2C_MAX_CLK_RATE)
563 		return dev_err_probe(&pdev->dev, -EINVAL,
564 				     "PCLK missing or out of range (%d)\n",
565 				     i2c->pclkrate);
566 
567 	i2c->base = devm_platform_ioremap_resource(pdev, 0);
568 	if (IS_ERR(i2c->base))
569 		return PTR_ERR(i2c->base);
570 
571 	i2c->irq = platform_get_irq(pdev, 0);
572 	if (i2c->irq < 0)
573 		return i2c->irq;
574 
575 	ret = devm_request_irq(&pdev->dev, i2c->irq, synquacer_i2c_isr,
576 			       0, dev_name(&pdev->dev), i2c);
577 	if (ret < 0)
578 		return dev_err_probe(&pdev->dev, ret, "cannot claim IRQ %d\n", i2c->irq);
579 
580 	i2c->state = STATE_IDLE;
581 	i2c->dev = &pdev->dev;
582 	i2c->adapter = synquacer_i2c_ops;
583 	i2c_set_adapdata(&i2c->adapter, i2c);
584 	i2c->adapter.dev.parent = &pdev->dev;
585 	i2c->adapter.dev.of_node = pdev->dev.of_node;
586 	ACPI_COMPANION_SET(&i2c->adapter.dev, ACPI_COMPANION(&pdev->dev));
587 	i2c->adapter.nr = pdev->id;
588 	init_completion(&i2c->completion);
589 
590 	if (bus_speed < I2C_MAX_FAST_MODE_FREQ)
591 		i2c->speed_khz = SYNQUACER_I2C_SPEED_SM;
592 	else
593 		i2c->speed_khz = SYNQUACER_I2C_SPEED_FM;
594 
595 	synquacer_i2c_hw_init(i2c);
596 
597 	ret = i2c_add_numbered_adapter(&i2c->adapter);
598 	if (ret)
599 		return dev_err_probe(&pdev->dev, ret, "failed to add bus to i2c core\n");
600 
601 	platform_set_drvdata(pdev, i2c);
602 
603 	dev_info(&pdev->dev, "%s: synquacer_i2c adapter\n",
604 		 dev_name(&i2c->adapter.dev));
605 
606 	return 0;
607 }
608 
609 static void synquacer_i2c_remove(struct platform_device *pdev)
610 {
611 	struct synquacer_i2c *i2c = platform_get_drvdata(pdev);
612 
613 	i2c_del_adapter(&i2c->adapter);
614 };
615 
616 static const struct of_device_id synquacer_i2c_dt_ids[] __maybe_unused = {
617 	{ .compatible = "socionext,synquacer-i2c" },
618 	{ /* sentinel */ }
619 };
620 MODULE_DEVICE_TABLE(of, synquacer_i2c_dt_ids);
621 
622 #ifdef CONFIG_ACPI
623 static const struct acpi_device_id synquacer_i2c_acpi_ids[] = {
624 	{ "SCX0003" },
625 	{ /* sentinel */ }
626 };
627 MODULE_DEVICE_TABLE(acpi, synquacer_i2c_acpi_ids);
628 #endif
629 
630 static struct platform_driver synquacer_i2c_driver = {
631 	.probe	= synquacer_i2c_probe,
632 	.remove = synquacer_i2c_remove,
633 	.driver	= {
634 		.name = "synquacer_i2c",
635 		.of_match_table = of_match_ptr(synquacer_i2c_dt_ids),
636 		.acpi_match_table = ACPI_PTR(synquacer_i2c_acpi_ids),
637 	},
638 };
639 module_platform_driver(synquacer_i2c_driver);
640 
641 MODULE_AUTHOR("Fujitsu Semiconductor Ltd");
642 MODULE_DESCRIPTION("Socionext SynQuacer I2C Driver");
643 MODULE_LICENSE("GPL v2");
644