xref: /linux/drivers/i2c/busses/i2c-rcar.c (revision 6e7fd890f1d6ac83805409e9c346240de2705584)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Driver for the Renesas R-Car I2C unit
4  *
5  * Copyright (C) 2014-19 Wolfram Sang <wsa@sang-engineering.com>
6  * Copyright (C) 2011-2019 Renesas Electronics Corporation
7  *
8  * Copyright (C) 2012-14 Renesas Solutions Corp.
9  * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
10  *
11  * This file is based on the drivers/i2c/busses/i2c-sh7760.c
12  * (c) 2005-2008 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com>
13  */
14 #include <linux/bitops.h>
15 #include <linux/clk.h>
16 #include <linux/delay.h>
17 #include <linux/dmaengine.h>
18 #include <linux/dma-mapping.h>
19 #include <linux/err.h>
20 #include <linux/interrupt.h>
21 #include <linux/io.h>
22 #include <linux/iopoll.h>
23 #include <linux/i2c.h>
24 #include <linux/i2c-smbus.h>
25 #include <linux/kernel.h>
26 #include <linux/module.h>
27 #include <linux/of.h>
28 #include <linux/platform_device.h>
29 #include <linux/pm_runtime.h>
30 #include <linux/reset.h>
31 #include <linux/slab.h>
32 
33 /* register offsets */
34 #define ICSCR	0x00	/* slave ctrl */
35 #define ICMCR	0x04	/* master ctrl */
36 #define ICSSR	0x08	/* slave status */
37 #define ICMSR	0x0C	/* master status */
38 #define ICSIER	0x10	/* slave irq enable */
39 #define ICMIER	0x14	/* master irq enable */
40 #define ICCCR	0x18	/* clock dividers */
41 #define ICSAR	0x1C	/* slave address */
42 #define ICMAR	0x20	/* master address */
43 #define ICRXTX	0x24	/* data port */
44 #define ICCCR2	0x28	/* Clock control 2 */
45 #define ICMPR	0x2C	/* SCL mask control */
46 #define ICHPR	0x30	/* SCL HIGH control */
47 #define ICLPR	0x34	/* SCL LOW control */
48 #define ICFBSCR	0x38	/* first bit setup cycle (Gen3) */
49 #define ICDMAER	0x3c	/* DMA enable (Gen3) */
50 
51 /* ICSCR */
52 #define SDBS	BIT(3)	/* slave data buffer select */
53 #define SIE	BIT(2)	/* slave interface enable */
54 #define GCAE	BIT(1)	/* general call address enable */
55 #define FNA	BIT(0)	/* forced non acknowledgment */
56 
57 /* ICMCR */
58 #define MDBS	BIT(7)	/* non-fifo mode switch */
59 #define FSCL	BIT(6)	/* override SCL pin */
60 #define FSDA	BIT(5)	/* override SDA pin */
61 #define OBPC	BIT(4)	/* override pins */
62 #define MIE	BIT(3)	/* master if enable */
63 #define TSBE	BIT(2)
64 #define FSB	BIT(1)	/* force stop bit */
65 #define ESG	BIT(0)	/* enable start bit gen */
66 
67 /* ICSSR (also for ICSIER) */
68 #define GCAR	BIT(6)	/* general call received */
69 #define STM	BIT(5)	/* slave transmit mode */
70 #define SSR	BIT(4)	/* stop received */
71 #define SDE	BIT(3)	/* slave data empty */
72 #define SDT	BIT(2)	/* slave data transmitted */
73 #define SDR	BIT(1)	/* slave data received */
74 #define SAR	BIT(0)	/* slave addr received */
75 
76 /* ICMSR (also for ICMIE) */
77 #define MNR	BIT(6)	/* nack received */
78 #define MAL	BIT(5)	/* arbitration lost */
79 #define MST	BIT(4)	/* sent a stop */
80 #define MDE	BIT(3)
81 #define MDT	BIT(2)
82 #define MDR	BIT(1)
83 #define MAT	BIT(0)	/* slave addr xfer done */
84 
85 /* ICDMAER */
86 #define RSDMAE	BIT(3)	/* DMA Slave Received Enable */
87 #define TSDMAE	BIT(2)	/* DMA Slave Transmitted Enable */
88 #define RMDMAE	BIT(1)	/* DMA Master Received Enable */
89 #define TMDMAE	BIT(0)	/* DMA Master Transmitted Enable */
90 
91 /* ICCCR2 */
92 #define FMPE	BIT(7)	/* Fast Mode Plus Enable */
93 #define CDFD	BIT(2)	/* CDF Disable */
94 #define HLSE	BIT(1)	/* HIGH/LOW Separate Control Enable */
95 #define SME	BIT(0)	/* SCL Mask Enable */
96 
97 /* ICFBSCR */
98 #define TCYC17	0x0f		/* 17*Tcyc delay 1st bit between SDA and SCL */
99 
100 #define RCAR_MIN_DMA_LEN	8
101 
102 /* SCL low/high ratio 5:4 to meet all I2C timing specs (incl safety margin) */
103 #define RCAR_SCLD_RATIO		5
104 #define RCAR_SCHD_RATIO		4
105 /*
106  * SMD should be smaller than SCLD/SCHD and is always around 20 in the docs.
107  * Thus, we simply use 20 which works for low and high speeds.
108  */
109 #define RCAR_DEFAULT_SMD	20
110 
111 #define RCAR_BUS_PHASE_START	(MDBS | MIE | ESG)
112 #define RCAR_BUS_PHASE_DATA	(MDBS | MIE)
113 #define RCAR_BUS_PHASE_STOP	(MDBS | MIE | FSB)
114 
115 #define RCAR_IRQ_SEND	(MNR | MAL | MST | MAT | MDE)
116 #define RCAR_IRQ_RECV	(MNR | MAL | MST | MAT | MDR)
117 #define RCAR_IRQ_STOP	(MST)
118 
119 #define ID_LAST_MSG		BIT(0)
120 #define ID_REP_AFTER_RD		BIT(1)
121 #define ID_DONE			BIT(2)
122 #define ID_ARBLOST		BIT(3)
123 #define ID_NACK			BIT(4)
124 #define ID_EPROTO		BIT(5)
125 /* persistent flags */
126 #define ID_P_FMPLUS		BIT(27)
127 #define ID_P_NOT_ATOMIC		BIT(28)
128 #define ID_P_HOST_NOTIFY	BIT(29)
129 #define ID_P_NO_RXDMA		BIT(30) /* HW forbids RXDMA sometimes */
130 #define ID_P_PM_BLOCKED		BIT(31)
131 #define ID_P_MASK		GENMASK(31, 27)
132 
133 enum rcar_i2c_type {
134 	I2C_RCAR_GEN1,
135 	I2C_RCAR_GEN2,
136 	I2C_RCAR_GEN3,
137 	I2C_RCAR_GEN4,
138 };
139 
140 struct rcar_i2c_priv {
141 	u32 flags;
142 	void __iomem *io;
143 	struct i2c_adapter adap;
144 	struct i2c_msg *msg;
145 	int msgs_left;
146 	struct clk *clk;
147 
148 	wait_queue_head_t wait;
149 
150 	int pos;
151 	u32 icccr;
152 	u16 schd;
153 	u16 scld;
154 	u8 smd;
155 	u8 recovery_icmcr;	/* protected by adapter lock */
156 	enum rcar_i2c_type devtype;
157 	struct i2c_client *slave;
158 
159 	struct resource *res;
160 	struct dma_chan *dma_tx;
161 	struct dma_chan *dma_rx;
162 	struct scatterlist sg;
163 	enum dma_data_direction dma_direction;
164 
165 	struct reset_control *rstc;
166 	int irq;
167 
168 	struct i2c_client *host_notify_client;
169 };
170 
171 #define rcar_i2c_priv_to_dev(p)		((p)->adap.dev.parent)
172 #define rcar_i2c_is_recv(p)		((p)->msg->flags & I2C_M_RD)
173 
174 static void rcar_i2c_write(struct rcar_i2c_priv *priv, int reg, u32 val)
175 {
176 	writel(val, priv->io + reg);
177 }
178 
179 static u32 rcar_i2c_read(struct rcar_i2c_priv *priv, int reg)
180 {
181 	return readl(priv->io + reg);
182 }
183 
184 static void rcar_i2c_clear_irq(struct rcar_i2c_priv *priv, u32 val)
185 {
186 	writel(~val & 0x7f, priv->io + ICMSR);
187 }
188 
189 static int rcar_i2c_get_scl(struct i2c_adapter *adap)
190 {
191 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
192 
193 	return !!(rcar_i2c_read(priv, ICMCR) & FSCL);
194 }
195 
196 static void rcar_i2c_set_scl(struct i2c_adapter *adap, int val)
197 {
198 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
199 
200 	if (val)
201 		priv->recovery_icmcr |= FSCL;
202 	else
203 		priv->recovery_icmcr &= ~FSCL;
204 
205 	rcar_i2c_write(priv, ICMCR, priv->recovery_icmcr);
206 }
207 
208 static void rcar_i2c_set_sda(struct i2c_adapter *adap, int val)
209 {
210 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
211 
212 	if (val)
213 		priv->recovery_icmcr |= FSDA;
214 	else
215 		priv->recovery_icmcr &= ~FSDA;
216 
217 	rcar_i2c_write(priv, ICMCR, priv->recovery_icmcr);
218 }
219 
220 static int rcar_i2c_get_bus_free(struct i2c_adapter *adap)
221 {
222 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
223 
224 	return !(rcar_i2c_read(priv, ICMCR) & FSDA);
225 }
226 
227 static struct i2c_bus_recovery_info rcar_i2c_bri = {
228 	.get_scl = rcar_i2c_get_scl,
229 	.set_scl = rcar_i2c_set_scl,
230 	.set_sda = rcar_i2c_set_sda,
231 	.get_bus_free = rcar_i2c_get_bus_free,
232 	.recover_bus = i2c_generic_scl_recovery,
233 };
234 
235 static void rcar_i2c_init(struct rcar_i2c_priv *priv)
236 {
237 	/* reset master mode */
238 	rcar_i2c_write(priv, ICMIER, 0);
239 	rcar_i2c_write(priv, ICMCR, MDBS);
240 	rcar_i2c_write(priv, ICMSR, 0);
241 	/* start clock */
242 	if (priv->devtype < I2C_RCAR_GEN3) {
243 		rcar_i2c_write(priv, ICCCR, priv->icccr);
244 	} else {
245 		u32 icccr2 = CDFD | HLSE | SME;
246 
247 		if (priv->flags & ID_P_FMPLUS)
248 			icccr2 |= FMPE;
249 
250 		rcar_i2c_write(priv, ICCCR2, icccr2);
251 		rcar_i2c_write(priv, ICCCR, priv->icccr);
252 		rcar_i2c_write(priv, ICMPR, priv->smd);
253 		rcar_i2c_write(priv, ICHPR, priv->schd);
254 		rcar_i2c_write(priv, ICLPR, priv->scld);
255 		rcar_i2c_write(priv, ICFBSCR, TCYC17);
256 	}
257 }
258 
259 static void rcar_i2c_reset_slave(struct rcar_i2c_priv *priv)
260 {
261 	rcar_i2c_write(priv, ICSIER, 0);
262 	rcar_i2c_write(priv, ICSSR, 0);
263 	rcar_i2c_write(priv, ICSCR, SDBS);
264 	rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */
265 }
266 
267 static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv)
268 {
269 	int ret;
270 	u32 val;
271 
272 	ret = readl_poll_timeout(priv->io + ICMCR, val, !(val & FSDA), 10,
273 				 priv->adap.timeout);
274 	if (ret) {
275 		/* Waiting did not help, try to recover */
276 		priv->recovery_icmcr = MDBS | OBPC | FSDA | FSCL;
277 		ret = i2c_recover_bus(&priv->adap);
278 	}
279 
280 	return ret;
281 }
282 
283 static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv)
284 {
285 	u32 cdf, round, ick, sum, scl, cdf_width;
286 	unsigned long rate;
287 	struct device *dev = rcar_i2c_priv_to_dev(priv);
288 	struct i2c_timings t = {
289 		.bus_freq_hz		= I2C_MAX_STANDARD_MODE_FREQ,
290 		.scl_fall_ns		= 35,
291 		.scl_rise_ns		= 200,
292 		.scl_int_delay_ns	= 50,
293 	};
294 
295 	/* Fall back to previously used values if not supplied */
296 	i2c_parse_fw_timings(dev, &t, false);
297 	priv->smd = RCAR_DEFAULT_SMD;
298 
299 	/*
300 	 * calculate SCL clock
301 	 * see
302 	 *	ICCCR (and ICCCR2 for Gen3+)
303 	 *
304 	 * ick	= clkp / (1 + CDF)
305 	 * SCL	= ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
306 	 *
307 	 * for Gen3+:
308 	 * SCL	= clkp / (8 + SMD * 2 + SCLD + SCHD +F[(ticf + tr + intd) * clkp])
309 	 *
310 	 * ick  : I2C internal clock < 20 MHz
311 	 * ticf : I2C SCL falling time
312 	 * tr   : I2C SCL rising  time
313 	 * intd : LSI internal delay
314 	 * clkp : peripheral_clk
315 	 * F[]  : integer up-valuation
316 	 */
317 	rate = clk_get_rate(priv->clk);
318 	cdf = rate / 20000000;
319 	cdf_width = (priv->devtype == I2C_RCAR_GEN1) ? 2 : 3;
320 	if (cdf >= 1U << cdf_width)
321 		goto err_no_val;
322 
323 	if (t.bus_freq_hz > I2C_MAX_FAST_MODE_FREQ && priv->devtype >= I2C_RCAR_GEN4)
324 		priv->flags |= ID_P_FMPLUS;
325 	else
326 		priv->flags &= ~ID_P_FMPLUS;
327 
328 	/* On Gen3+, we use cdf only for the filters, not as a SCL divider */
329 	ick = rate / (priv->devtype < I2C_RCAR_GEN3 ? (cdf + 1) : 1);
330 
331 	/*
332 	 * It is impossible to calculate a large scale number on u32. Separate it.
333 	 *
334 	 * F[(ticf + tr + intd) * ick] with sum = (ticf + tr + intd)
335 	 *  = F[sum * ick / 1000000000]
336 	 *  = F[(ick / 1000000) * sum / 1000]
337 	 */
338 	sum = t.scl_fall_ns + t.scl_rise_ns + t.scl_int_delay_ns;
339 	round = DIV_ROUND_CLOSEST(ick, 1000000);
340 	round = DIV_ROUND_CLOSEST(round * sum, 1000);
341 
342 	if (priv->devtype < I2C_RCAR_GEN3) {
343 		u32 scgd;
344 		/*
345 		 * SCL	= ick / (20 + 8 * SCGD + F[(ticf + tr + intd) * ick])
346 		 * 20 + 8 * SCGD + F[...] = ick / SCL
347 		 * SCGD = ((ick / SCL) - 20 - F[...]) / 8
348 		 * Result (= SCL) should be less than bus_speed for hardware safety
349 		 */
350 		scgd = DIV_ROUND_UP(ick, t.bus_freq_hz ?: 1);
351 		scgd = DIV_ROUND_UP(scgd - 20 - round, 8);
352 		scl = ick / (20 + 8 * scgd + round);
353 
354 		if (scgd > 0x3f)
355 			goto err_no_val;
356 
357 		dev_dbg(dev, "clk %u/%u(%lu), round %u, CDF: %u, SCGD: %u\n",
358 			scl, t.bus_freq_hz, rate, round, cdf, scgd);
359 
360 		priv->icccr = scgd << cdf_width | cdf;
361 	} else {
362 		u32 x, sum_ratio = RCAR_SCHD_RATIO + RCAR_SCLD_RATIO;
363 		/*
364 		 * SCLD/SCHD ratio and SMD default value are explained above
365 		 * where they are defined. With these definitions, we can compute
366 		 * x as a base value for the SCLD/SCHD ratio:
367 		 *
368 		 * SCL = clkp / (8 + 2 * SMD + SCLD + SCHD + F[(ticf + tr + intd) * clkp])
369 		 * SCL = clkp / (8 + 2 * SMD + RCAR_SCLD_RATIO * x
370 		 *		 + RCAR_SCHD_RATIO * x + F[...])
371 		 *
372 		 * with: sum_ratio = RCAR_SCLD_RATIO + RCAR_SCHD_RATIO
373 		 *
374 		 * SCL = clkp / (8 + 2 * smd + sum_ratio * x + F[...])
375 		 * 8 + 2 * smd + sum_ratio * x + F[...] = clkp / SCL
376 		 * x = ((clkp / SCL) - 8 - 2 * smd - F[...]) / sum_ratio
377 		 */
378 		x = DIV_ROUND_UP(rate, t.bus_freq_hz ?: 1);
379 		x = DIV_ROUND_UP(x - 8 - 2 * priv->smd - round, sum_ratio);
380 		scl = rate / (8 + 2 * priv->smd + sum_ratio * x + round);
381 
382 		if (x == 0 || x * RCAR_SCLD_RATIO > 0xffff)
383 			goto err_no_val;
384 
385 		priv->icccr = cdf;
386 		priv->schd = RCAR_SCHD_RATIO * x;
387 		priv->scld = RCAR_SCLD_RATIO * x;
388 		if (priv->smd >= priv->schd)
389 			priv->smd = priv->schd - 1;
390 
391 		dev_dbg(dev, "clk %u/%u(%lu), round %u, CDF: %u SCHD %u SCLD %u SMD %u\n",
392 			scl, t.bus_freq_hz, rate, round, cdf, priv->schd, priv->scld, priv->smd);
393 	}
394 
395 	return 0;
396 
397 err_no_val:
398 	dev_err(dev, "it is impossible to calculate best SCL\n");
399 	return -EINVAL;
400 }
401 
402 /*
403  * We don't have a test case but the HW engineers say that the write order of
404  * ICMSR and ICMCR depends on whether we issue START or REP_START. So, ICMSR
405  * handling is outside of this function. First messages clear ICMSR before this
406  * function, interrupt handlers clear the relevant bits after this function.
407  */
408 static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv)
409 {
410 	int read = !!rcar_i2c_is_recv(priv);
411 	bool rep_start = !(priv->flags & ID_REP_AFTER_RD);
412 
413 	priv->pos = 0;
414 	priv->flags &= ID_P_MASK;
415 
416 	if (priv->msgs_left == 1)
417 		priv->flags |= ID_LAST_MSG;
418 
419 	rcar_i2c_write(priv, ICMAR, i2c_8bit_addr_from_msg(priv->msg));
420 	if (priv->flags & ID_P_NOT_ATOMIC)
421 		rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND);
422 
423 	if (rep_start)
424 		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
425 }
426 
427 static void rcar_i2c_first_msg(struct rcar_i2c_priv *priv,
428 			       struct i2c_msg *msgs, int num)
429 {
430 	priv->msg = msgs;
431 	priv->msgs_left = num;
432 	rcar_i2c_write(priv, ICMSR, 0); /* must be before preparing msg */
433 	rcar_i2c_prepare_msg(priv);
434 }
435 
436 static void rcar_i2c_next_msg(struct rcar_i2c_priv *priv)
437 {
438 	priv->msg++;
439 	priv->msgs_left--;
440 	rcar_i2c_prepare_msg(priv);
441 	/* ICMSR handling must come afterwards in the irq handler */
442 }
443 
444 static void rcar_i2c_cleanup_dma(struct rcar_i2c_priv *priv, bool terminate)
445 {
446 	struct dma_chan *chan = priv->dma_direction == DMA_FROM_DEVICE
447 		? priv->dma_rx : priv->dma_tx;
448 
449 	/* only allowed from thread context! */
450 	if (terminate)
451 		dmaengine_terminate_sync(chan);
452 
453 	dma_unmap_single(chan->device->dev, sg_dma_address(&priv->sg),
454 			 sg_dma_len(&priv->sg), priv->dma_direction);
455 
456 	/* Gen3+ can only do one RXDMA per transfer and we just completed it */
457 	if (priv->devtype >= I2C_RCAR_GEN3 &&
458 	    priv->dma_direction == DMA_FROM_DEVICE)
459 		priv->flags |= ID_P_NO_RXDMA;
460 
461 	priv->dma_direction = DMA_NONE;
462 
463 	/* Disable DMA Master Received/Transmitted, must be last! */
464 	rcar_i2c_write(priv, ICDMAER, 0);
465 }
466 
467 static void rcar_i2c_dma_callback(void *data)
468 {
469 	struct rcar_i2c_priv *priv = data;
470 
471 	priv->pos += sg_dma_len(&priv->sg);
472 
473 	rcar_i2c_cleanup_dma(priv, false);
474 }
475 
476 static bool rcar_i2c_dma(struct rcar_i2c_priv *priv)
477 {
478 	struct device *dev = rcar_i2c_priv_to_dev(priv);
479 	struct i2c_msg *msg = priv->msg;
480 	bool read = msg->flags & I2C_M_RD;
481 	enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
482 	struct dma_chan *chan = read ? priv->dma_rx : priv->dma_tx;
483 	struct dma_async_tx_descriptor *txdesc;
484 	dma_addr_t dma_addr;
485 	dma_cookie_t cookie;
486 	unsigned char *buf;
487 	int len;
488 
489 	/* Do various checks to see if DMA is feasible at all */
490 	if (!(priv->flags & ID_P_NOT_ATOMIC) || IS_ERR(chan) || msg->len < RCAR_MIN_DMA_LEN ||
491 	    !(msg->flags & I2C_M_DMA_SAFE) || (read && priv->flags & ID_P_NO_RXDMA))
492 		return false;
493 
494 	if (read) {
495 		/*
496 		 * The last two bytes needs to be fetched using PIO in
497 		 * order for the STOP phase to work.
498 		 */
499 		buf = priv->msg->buf;
500 		len = priv->msg->len - 2;
501 	} else {
502 		/*
503 		 * First byte in message was sent using PIO.
504 		 */
505 		buf = priv->msg->buf + 1;
506 		len = priv->msg->len - 1;
507 	}
508 
509 	dma_addr = dma_map_single(chan->device->dev, buf, len, dir);
510 	if (dma_mapping_error(chan->device->dev, dma_addr)) {
511 		dev_dbg(dev, "dma map failed, using PIO\n");
512 		return false;
513 	}
514 
515 	sg_dma_len(&priv->sg) = len;
516 	sg_dma_address(&priv->sg) = dma_addr;
517 
518 	priv->dma_direction = dir;
519 
520 	txdesc = dmaengine_prep_slave_sg(chan, &priv->sg, 1,
521 					 read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
522 					 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
523 	if (!txdesc) {
524 		dev_dbg(dev, "dma prep slave sg failed, using PIO\n");
525 		rcar_i2c_cleanup_dma(priv, false);
526 		return false;
527 	}
528 
529 	txdesc->callback = rcar_i2c_dma_callback;
530 	txdesc->callback_param = priv;
531 
532 	cookie = dmaengine_submit(txdesc);
533 	if (dma_submit_error(cookie)) {
534 		dev_dbg(dev, "submitting dma failed, using PIO\n");
535 		rcar_i2c_cleanup_dma(priv, false);
536 		return false;
537 	}
538 
539 	/* Enable DMA Master Received/Transmitted */
540 	if (read)
541 		rcar_i2c_write(priv, ICDMAER, RMDMAE);
542 	else
543 		rcar_i2c_write(priv, ICDMAER, TMDMAE);
544 
545 	dma_async_issue_pending(chan);
546 	return true;
547 }
548 
549 static void rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr)
550 {
551 	struct i2c_msg *msg = priv->msg;
552 	u32 irqs_to_clear = MDE;
553 
554 	/* FIXME: sometimes, unknown interrupt happened. Do nothing */
555 	if (WARN(!(msr & MDE), "spurious irq"))
556 		return;
557 
558 	if (msr & MAT)
559 		irqs_to_clear |= MAT;
560 
561 	/* Check if DMA can be enabled and take over */
562 	if (priv->pos == 1 && rcar_i2c_dma(priv))
563 		return;
564 
565 	if (priv->pos < msg->len) {
566 		/*
567 		 * Prepare next data to ICRXTX register.
568 		 * This data will go to _SHIFT_ register.
569 		 *
570 		 *    *
571 		 * [ICRXTX] -> [SHIFT] -> [I2C bus]
572 		 */
573 		rcar_i2c_write(priv, ICRXTX, msg->buf[priv->pos]);
574 		priv->pos++;
575 	} else {
576 		/*
577 		 * The last data was pushed to ICRXTX on _PREV_ empty irq.
578 		 * It is on _SHIFT_ register, and will sent to I2C bus.
579 		 *
580 		 *		  *
581 		 * [ICRXTX] -> [SHIFT] -> [I2C bus]
582 		 */
583 
584 		if (priv->flags & ID_LAST_MSG)
585 			/*
586 			 * If current msg is the _LAST_ msg,
587 			 * prepare stop condition here.
588 			 * ID_DONE will be set on STOP irq.
589 			 */
590 			rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
591 		else
592 			rcar_i2c_next_msg(priv);
593 	}
594 
595 	rcar_i2c_clear_irq(priv, irqs_to_clear);
596 }
597 
598 static void rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr)
599 {
600 	struct i2c_msg *msg = priv->msg;
601 	bool recv_len_init = priv->pos == 0 && msg->flags & I2C_M_RECV_LEN;
602 	u32 irqs_to_clear = MDR;
603 
604 	/* FIXME: sometimes, unknown interrupt happened. Do nothing */
605 	if (!(msr & MDR))
606 		return;
607 
608 	if (msr & MAT) {
609 		irqs_to_clear |= MAT;
610 		/*
611 		 * Address transfer phase finished, but no data at this point.
612 		 * Try to use DMA to receive data.
613 		 */
614 		rcar_i2c_dma(priv);
615 	} else if (priv->pos < msg->len) {
616 		/* get received data */
617 		u8 data = rcar_i2c_read(priv, ICRXTX);
618 
619 		msg->buf[priv->pos] = data;
620 		if (recv_len_init) {
621 			if (data == 0 || data > I2C_SMBUS_BLOCK_MAX) {
622 				priv->flags |= ID_DONE | ID_EPROTO;
623 				return;
624 			}
625 			msg->len += msg->buf[0];
626 			/* Enough data for DMA? */
627 			if (rcar_i2c_dma(priv))
628 				return;
629 			/* new length after RECV_LEN now properly initialized */
630 			recv_len_init = false;
631 		}
632 		priv->pos++;
633 	}
634 
635 	/*
636 	 * If next received data is the _LAST_ and we are not waiting for a new
637 	 * length because of RECV_LEN, then go to a new phase.
638 	 */
639 	if (priv->pos + 1 == msg->len && !recv_len_init) {
640 		if (priv->flags & ID_LAST_MSG) {
641 			rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
642 		} else {
643 			rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
644 			priv->flags |= ID_REP_AFTER_RD;
645 		}
646 	}
647 
648 	if (priv->pos == msg->len && !(priv->flags & ID_LAST_MSG))
649 		rcar_i2c_next_msg(priv);
650 
651 	rcar_i2c_clear_irq(priv, irqs_to_clear);
652 }
653 
654 static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
655 {
656 	u32 ssr_raw, ssr_filtered;
657 	u8 value;
658 
659 	ssr_raw = rcar_i2c_read(priv, ICSSR) & 0xff;
660 	ssr_filtered = ssr_raw & rcar_i2c_read(priv, ICSIER);
661 
662 	if (!ssr_filtered)
663 		return false;
664 
665 	/* address detected */
666 	if (ssr_filtered & SAR) {
667 		/* read or write request */
668 		if (ssr_raw & STM) {
669 			i2c_slave_event(priv->slave, I2C_SLAVE_READ_REQUESTED, &value);
670 			rcar_i2c_write(priv, ICRXTX, value);
671 			rcar_i2c_write(priv, ICSIER, SDE | SSR | SAR);
672 		} else {
673 			i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
674 			rcar_i2c_read(priv, ICRXTX);	/* dummy read */
675 			rcar_i2c_write(priv, ICSIER, SDR | SSR | SAR);
676 		}
677 
678 		/* Clear SSR, too, because of old STOPs to other clients than us */
679 		rcar_i2c_write(priv, ICSSR, ~(SAR | SSR) & 0xff);
680 	}
681 
682 	/* master sent stop */
683 	if (ssr_filtered & SSR) {
684 		i2c_slave_event(priv->slave, I2C_SLAVE_STOP, &value);
685 		rcar_i2c_write(priv, ICSCR, SIE | SDBS); /* clear our NACK */
686 		rcar_i2c_write(priv, ICSIER, SAR);
687 		rcar_i2c_write(priv, ICSSR, ~SSR & 0xff);
688 	}
689 
690 	/* master wants to write to us */
691 	if (ssr_filtered & SDR) {
692 		int ret;
693 
694 		value = rcar_i2c_read(priv, ICRXTX);
695 		ret = i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
696 		/* Send NACK in case of error */
697 		rcar_i2c_write(priv, ICSCR, SIE | SDBS | (ret < 0 ? FNA : 0));
698 		rcar_i2c_write(priv, ICSSR, ~SDR & 0xff);
699 	}
700 
701 	/* master wants to read from us */
702 	if (ssr_filtered & SDE) {
703 		i2c_slave_event(priv->slave, I2C_SLAVE_READ_PROCESSED, &value);
704 		rcar_i2c_write(priv, ICRXTX, value);
705 		rcar_i2c_write(priv, ICSSR, ~SDE & 0xff);
706 	}
707 
708 	return true;
709 }
710 
711 /*
712  * This driver has a lock-free design because there are IP cores (at least
713  * R-Car Gen2) which have an inherent race condition in their hardware design.
714  * There, we need to switch to RCAR_BUS_PHASE_DATA as soon as possible after
715  * the interrupt was generated, otherwise an unwanted repeated message gets
716  * generated. It turned out that taking a spinlock at the beginning of the ISR
717  * was already causing repeated messages. Thus, this driver was converted to
718  * the now lockless behaviour. Please keep this in mind when hacking the driver.
719  * R-Car Gen3 seems to have this fixed but earlier versions than R-Car Gen2 are
720  * likely affected. Therefore, we have different interrupt handler entries.
721  */
722 static irqreturn_t rcar_i2c_irq(int irq, struct rcar_i2c_priv *priv, u32 msr)
723 {
724 	if (!msr) {
725 		if (rcar_i2c_slave_irq(priv))
726 			return IRQ_HANDLED;
727 
728 		return IRQ_NONE;
729 	}
730 
731 	/* Arbitration lost */
732 	if (msr & MAL) {
733 		priv->flags |= ID_DONE | ID_ARBLOST;
734 		goto out;
735 	}
736 
737 	/* Nack */
738 	if (msr & MNR) {
739 		/* HW automatically sends STOP after received NACK */
740 		if (priv->flags & ID_P_NOT_ATOMIC)
741 			rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP);
742 		priv->flags |= ID_NACK;
743 		goto out;
744 	}
745 
746 	/* Stop */
747 	if (msr & MST) {
748 		priv->msgs_left--; /* The last message also made it */
749 		priv->flags |= ID_DONE;
750 		goto out;
751 	}
752 
753 	if (rcar_i2c_is_recv(priv))
754 		rcar_i2c_irq_recv(priv, msr);
755 	else
756 		rcar_i2c_irq_send(priv, msr);
757 
758 out:
759 	if (priv->flags & ID_DONE) {
760 		rcar_i2c_write(priv, ICMIER, 0);
761 		rcar_i2c_write(priv, ICMSR, 0);
762 		if (priv->flags & ID_P_NOT_ATOMIC)
763 			wake_up(&priv->wait);
764 	}
765 
766 	return IRQ_HANDLED;
767 }
768 
769 static irqreturn_t rcar_i2c_gen2_irq(int irq, void *ptr)
770 {
771 	struct rcar_i2c_priv *priv = ptr;
772 	u32 msr;
773 
774 	/* Clear START or STOP immediately, except for REPSTART after read */
775 	if (likely(!(priv->flags & ID_REP_AFTER_RD)))
776 		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
777 
778 	/* Only handle interrupts that are currently enabled */
779 	msr = rcar_i2c_read(priv, ICMSR);
780 	if (priv->flags & ID_P_NOT_ATOMIC)
781 		msr &= rcar_i2c_read(priv, ICMIER);
782 
783 	return rcar_i2c_irq(irq, priv, msr);
784 }
785 
786 static irqreturn_t rcar_i2c_gen3_irq(int irq, void *ptr)
787 {
788 	struct rcar_i2c_priv *priv = ptr;
789 	u32 msr;
790 
791 	/* Only handle interrupts that are currently enabled */
792 	msr = rcar_i2c_read(priv, ICMSR);
793 	if (priv->flags & ID_P_NOT_ATOMIC)
794 		msr &= rcar_i2c_read(priv, ICMIER);
795 
796 	/*
797 	 * Clear START or STOP immediately, except for REPSTART after read or
798 	 * if a spurious interrupt was detected.
799 	 */
800 	if (likely(!(priv->flags & ID_REP_AFTER_RD) && msr))
801 		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
802 
803 	return rcar_i2c_irq(irq, priv, msr);
804 }
805 
806 static struct dma_chan *rcar_i2c_request_dma_chan(struct device *dev,
807 					enum dma_transfer_direction dir,
808 					dma_addr_t port_addr)
809 {
810 	struct dma_chan *chan;
811 	struct dma_slave_config cfg;
812 	char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
813 	int ret;
814 
815 	chan = dma_request_chan(dev, chan_name);
816 	if (IS_ERR(chan)) {
817 		dev_dbg(dev, "request_channel failed for %s (%ld)\n",
818 			chan_name, PTR_ERR(chan));
819 		return chan;
820 	}
821 
822 	memset(&cfg, 0, sizeof(cfg));
823 	cfg.direction = dir;
824 	if (dir == DMA_MEM_TO_DEV) {
825 		cfg.dst_addr = port_addr;
826 		cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
827 	} else {
828 		cfg.src_addr = port_addr;
829 		cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
830 	}
831 
832 	ret = dmaengine_slave_config(chan, &cfg);
833 	if (ret) {
834 		dev_dbg(dev, "slave_config failed for %s (%d)\n",
835 			chan_name, ret);
836 		dma_release_channel(chan);
837 		return ERR_PTR(ret);
838 	}
839 
840 	dev_dbg(dev, "got DMA channel for %s\n", chan_name);
841 	return chan;
842 }
843 
844 static void rcar_i2c_request_dma(struct rcar_i2c_priv *priv,
845 				 struct i2c_msg *msg)
846 {
847 	struct device *dev = rcar_i2c_priv_to_dev(priv);
848 	bool read;
849 	struct dma_chan *chan;
850 	enum dma_transfer_direction dir;
851 
852 	read = msg->flags & I2C_M_RD;
853 
854 	chan = read ? priv->dma_rx : priv->dma_tx;
855 	if (PTR_ERR(chan) != -EPROBE_DEFER)
856 		return;
857 
858 	dir = read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV;
859 	chan = rcar_i2c_request_dma_chan(dev, dir, priv->res->start + ICRXTX);
860 
861 	if (read)
862 		priv->dma_rx = chan;
863 	else
864 		priv->dma_tx = chan;
865 }
866 
867 static void rcar_i2c_release_dma(struct rcar_i2c_priv *priv)
868 {
869 	if (!IS_ERR(priv->dma_tx)) {
870 		dma_release_channel(priv->dma_tx);
871 		priv->dma_tx = ERR_PTR(-EPROBE_DEFER);
872 	}
873 
874 	if (!IS_ERR(priv->dma_rx)) {
875 		dma_release_channel(priv->dma_rx);
876 		priv->dma_rx = ERR_PTR(-EPROBE_DEFER);
877 	}
878 }
879 
880 /* I2C is a special case, we need to poll the status of a reset */
881 static int rcar_i2c_do_reset(struct rcar_i2c_priv *priv)
882 {
883 	int ret;
884 
885 	/* Don't reset if a slave instance is currently running */
886 	if (priv->slave)
887 		return -EISCONN;
888 
889 	ret = reset_control_reset(priv->rstc);
890 	if (ret)
891 		return ret;
892 
893 	return read_poll_timeout_atomic(reset_control_status, ret, ret == 0, 1,
894 					100, false, priv->rstc);
895 }
896 
897 static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
898 				struct i2c_msg *msgs,
899 				int num)
900 {
901 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
902 	struct device *dev = rcar_i2c_priv_to_dev(priv);
903 	int i, ret;
904 	long time_left;
905 
906 	priv->flags |= ID_P_NOT_ATOMIC;
907 
908 	pm_runtime_get_sync(dev);
909 
910 	/* Check bus state before init otherwise bus busy info will be lost */
911 	ret = rcar_i2c_bus_barrier(priv);
912 	if (ret < 0)
913 		goto out;
914 
915 	/* Gen3+ needs a reset. That also allows RXDMA once */
916 	if (priv->devtype >= I2C_RCAR_GEN3) {
917 		ret = rcar_i2c_do_reset(priv);
918 		if (ret)
919 			goto out;
920 		priv->flags &= ~ID_P_NO_RXDMA;
921 	}
922 
923 	rcar_i2c_init(priv);
924 
925 	for (i = 0; i < num; i++)
926 		rcar_i2c_request_dma(priv, msgs + i);
927 
928 	rcar_i2c_first_msg(priv, msgs, num);
929 
930 	time_left = wait_event_timeout(priv->wait, priv->flags & ID_DONE,
931 				     num * adap->timeout);
932 
933 	/* cleanup DMA if it couldn't complete properly due to an error */
934 	if (priv->dma_direction != DMA_NONE)
935 		rcar_i2c_cleanup_dma(priv, true);
936 
937 	if (!time_left) {
938 		rcar_i2c_init(priv);
939 		ret = -ETIMEDOUT;
940 	} else if (priv->flags & ID_NACK) {
941 		ret = -ENXIO;
942 	} else if (priv->flags & ID_ARBLOST) {
943 		ret = -EAGAIN;
944 	} else if (priv->flags & ID_EPROTO) {
945 		ret = -EPROTO;
946 	} else {
947 		ret = num - priv->msgs_left; /* The number of transfer */
948 	}
949 out:
950 	pm_runtime_put(dev);
951 
952 	if (ret < 0 && ret != -ENXIO)
953 		dev_err(dev, "error %d : %x\n", ret, priv->flags);
954 
955 	return ret;
956 }
957 
958 static int rcar_i2c_master_xfer_atomic(struct i2c_adapter *adap,
959 				struct i2c_msg *msgs,
960 				int num)
961 {
962 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
963 	struct device *dev = rcar_i2c_priv_to_dev(priv);
964 	unsigned long j;
965 	bool time_left;
966 	int ret;
967 
968 	priv->flags &= ~ID_P_NOT_ATOMIC;
969 
970 	pm_runtime_get_sync(dev);
971 
972 	/* Check bus state before init otherwise bus busy info will be lost */
973 	ret = rcar_i2c_bus_barrier(priv);
974 	if (ret < 0)
975 		goto out;
976 
977 	rcar_i2c_init(priv);
978 	rcar_i2c_first_msg(priv, msgs, num);
979 
980 	j = jiffies + num * adap->timeout;
981 	do {
982 		u32 msr = rcar_i2c_read(priv, ICMSR);
983 
984 		msr &= (rcar_i2c_is_recv(priv) ? RCAR_IRQ_RECV : RCAR_IRQ_SEND) | RCAR_IRQ_STOP;
985 
986 		if (msr) {
987 			if (priv->devtype < I2C_RCAR_GEN3)
988 				rcar_i2c_gen2_irq(0, priv);
989 			else
990 				rcar_i2c_gen3_irq(0, priv);
991 		}
992 
993 		time_left = time_before_eq(jiffies, j);
994 	} while (!(priv->flags & ID_DONE) && time_left);
995 
996 	if (!time_left) {
997 		rcar_i2c_init(priv);
998 		ret = -ETIMEDOUT;
999 	} else if (priv->flags & ID_NACK) {
1000 		ret = -ENXIO;
1001 	} else if (priv->flags & ID_ARBLOST) {
1002 		ret = -EAGAIN;
1003 	} else if (priv->flags & ID_EPROTO) {
1004 		ret = -EPROTO;
1005 	} else {
1006 		ret = num - priv->msgs_left; /* The number of transfer */
1007 	}
1008 out:
1009 	pm_runtime_put(dev);
1010 
1011 	if (ret < 0 && ret != -ENXIO)
1012 		dev_err(dev, "error %d : %x\n", ret, priv->flags);
1013 
1014 	return ret;
1015 }
1016 
1017 static int rcar_reg_slave(struct i2c_client *slave)
1018 {
1019 	struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
1020 
1021 	if (priv->slave)
1022 		return -EBUSY;
1023 
1024 	if (slave->flags & I2C_CLIENT_TEN)
1025 		return -EAFNOSUPPORT;
1026 
1027 	/* Keep device active for slave address detection logic */
1028 	pm_runtime_get_sync(rcar_i2c_priv_to_dev(priv));
1029 
1030 	priv->slave = slave;
1031 	rcar_i2c_write(priv, ICSAR, slave->addr);
1032 	rcar_i2c_write(priv, ICSSR, 0);
1033 	rcar_i2c_write(priv, ICSIER, SAR);
1034 	rcar_i2c_write(priv, ICSCR, SIE | SDBS);
1035 
1036 	return 0;
1037 }
1038 
1039 static int rcar_unreg_slave(struct i2c_client *slave)
1040 {
1041 	struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
1042 
1043 	WARN_ON(!priv->slave);
1044 
1045 	/* ensure no irq is running before clearing ptr */
1046 	disable_irq(priv->irq);
1047 	rcar_i2c_reset_slave(priv);
1048 	enable_irq(priv->irq);
1049 
1050 	priv->slave = NULL;
1051 
1052 	pm_runtime_put(rcar_i2c_priv_to_dev(priv));
1053 
1054 	return 0;
1055 }
1056 
1057 static u32 rcar_i2c_func(struct i2c_adapter *adap)
1058 {
1059 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
1060 
1061 	/*
1062 	 * This HW can't do:
1063 	 * I2C_SMBUS_QUICK (setting FSB during START didn't work)
1064 	 * I2C_M_NOSTART (automatically sends address after START)
1065 	 * I2C_M_IGNORE_NAK (automatically sends STOP after NAK)
1066 	 */
1067 	u32 func = I2C_FUNC_I2C | I2C_FUNC_SLAVE |
1068 		   (I2C_FUNC_SMBUS_EMUL_ALL & ~I2C_FUNC_SMBUS_QUICK);
1069 
1070 	if (priv->flags & ID_P_HOST_NOTIFY)
1071 		func |= I2C_FUNC_SMBUS_HOST_NOTIFY;
1072 
1073 	return func;
1074 }
1075 
1076 static const struct i2c_algorithm rcar_i2c_algo = {
1077 	.master_xfer	= rcar_i2c_master_xfer,
1078 	.master_xfer_atomic = rcar_i2c_master_xfer_atomic,
1079 	.functionality	= rcar_i2c_func,
1080 	.reg_slave	= rcar_reg_slave,
1081 	.unreg_slave	= rcar_unreg_slave,
1082 };
1083 
1084 static const struct i2c_adapter_quirks rcar_i2c_quirks = {
1085 	.flags = I2C_AQ_NO_ZERO_LEN,
1086 };
1087 
1088 static const struct of_device_id rcar_i2c_dt_ids[] = {
1089 	{ .compatible = "renesas,i2c-r8a7778", .data = (void *)I2C_RCAR_GEN1 },
1090 	{ .compatible = "renesas,i2c-r8a7779", .data = (void *)I2C_RCAR_GEN1 },
1091 	{ .compatible = "renesas,i2c-r8a7790", .data = (void *)I2C_RCAR_GEN2 },
1092 	{ .compatible = "renesas,i2c-r8a7791", .data = (void *)I2C_RCAR_GEN2 },
1093 	{ .compatible = "renesas,i2c-r8a7792", .data = (void *)I2C_RCAR_GEN2 },
1094 	{ .compatible = "renesas,i2c-r8a7793", .data = (void *)I2C_RCAR_GEN2 },
1095 	{ .compatible = "renesas,i2c-r8a7794", .data = (void *)I2C_RCAR_GEN2 },
1096 	{ .compatible = "renesas,i2c-r8a7795", .data = (void *)I2C_RCAR_GEN3 },
1097 	{ .compatible = "renesas,i2c-r8a7796", .data = (void *)I2C_RCAR_GEN3 },
1098 	/* S4 has no FM+ bit */
1099 	{ .compatible = "renesas,i2c-r8a779f0", .data = (void *)I2C_RCAR_GEN3 },
1100 	{ .compatible = "renesas,rcar-gen1-i2c", .data = (void *)I2C_RCAR_GEN1 },
1101 	{ .compatible = "renesas,rcar-gen2-i2c", .data = (void *)I2C_RCAR_GEN2 },
1102 	{ .compatible = "renesas,rcar-gen3-i2c", .data = (void *)I2C_RCAR_GEN3 },
1103 	{ .compatible = "renesas,rcar-gen4-i2c", .data = (void *)I2C_RCAR_GEN4 },
1104 	{},
1105 };
1106 MODULE_DEVICE_TABLE(of, rcar_i2c_dt_ids);
1107 
1108 static int rcar_i2c_probe(struct platform_device *pdev)
1109 {
1110 	struct rcar_i2c_priv *priv;
1111 	struct i2c_adapter *adap;
1112 	struct device *dev = &pdev->dev;
1113 	unsigned long irqflags = 0;
1114 	irqreturn_t (*irqhandler)(int irq, void *ptr) = rcar_i2c_gen3_irq;
1115 	int ret;
1116 
1117 	/* Otherwise logic will break because some bytes must always use PIO */
1118 	BUILD_BUG_ON_MSG(RCAR_MIN_DMA_LEN < 3, "Invalid min DMA length");
1119 
1120 	priv = devm_kzalloc(dev, sizeof(struct rcar_i2c_priv), GFP_KERNEL);
1121 	if (!priv)
1122 		return -ENOMEM;
1123 
1124 	priv->clk = devm_clk_get(dev, NULL);
1125 	if (IS_ERR(priv->clk)) {
1126 		dev_err(dev, "cannot get clock\n");
1127 		return PTR_ERR(priv->clk);
1128 	}
1129 
1130 	priv->io = devm_platform_get_and_ioremap_resource(pdev, 0, &priv->res);
1131 	if (IS_ERR(priv->io))
1132 		return PTR_ERR(priv->io);
1133 
1134 	priv->devtype = (enum rcar_i2c_type)of_device_get_match_data(dev);
1135 	init_waitqueue_head(&priv->wait);
1136 
1137 	adap = &priv->adap;
1138 	adap->nr = pdev->id;
1139 	adap->algo = &rcar_i2c_algo;
1140 	adap->class = I2C_CLASS_DEPRECATED;
1141 	adap->retries = 3;
1142 	adap->dev.parent = dev;
1143 	adap->dev.of_node = dev->of_node;
1144 	adap->bus_recovery_info = &rcar_i2c_bri;
1145 	adap->quirks = &rcar_i2c_quirks;
1146 	i2c_set_adapdata(adap, priv);
1147 	strscpy(adap->name, pdev->name, sizeof(adap->name));
1148 
1149 	/* Init DMA */
1150 	sg_init_table(&priv->sg, 1);
1151 	priv->dma_direction = DMA_NONE;
1152 	priv->dma_rx = priv->dma_tx = ERR_PTR(-EPROBE_DEFER);
1153 
1154 	/* Activate device for clock calculation */
1155 	pm_runtime_enable(dev);
1156 	pm_runtime_get_sync(dev);
1157 	ret = rcar_i2c_clock_calculate(priv);
1158 	if (ret < 0) {
1159 		pm_runtime_put(dev);
1160 		goto out_pm_disable;
1161 	}
1162 
1163 	/* Bring hardware to known state */
1164 	rcar_i2c_init(priv);
1165 	rcar_i2c_reset_slave(priv);
1166 
1167 	if (priv->devtype < I2C_RCAR_GEN3) {
1168 		irqflags |= IRQF_NO_THREAD;
1169 		irqhandler = rcar_i2c_gen2_irq;
1170 	}
1171 
1172 	/* Stay always active when multi-master to keep arbitration working */
1173 	if (of_property_read_bool(dev->of_node, "multi-master"))
1174 		priv->flags |= ID_P_PM_BLOCKED;
1175 	else
1176 		pm_runtime_put(dev);
1177 
1178 	if (of_property_read_bool(dev->of_node, "smbus"))
1179 		priv->flags |= ID_P_HOST_NOTIFY;
1180 
1181 	/* R-Car Gen3+ needs a reset before every transfer */
1182 	if (priv->devtype >= I2C_RCAR_GEN3) {
1183 		priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
1184 		if (IS_ERR(priv->rstc)) {
1185 			ret = PTR_ERR(priv->rstc);
1186 			goto out_pm_put;
1187 		}
1188 
1189 		ret = reset_control_status(priv->rstc);
1190 		if (ret < 0)
1191 			goto out_pm_put;
1192 
1193 		/* hard reset disturbs HostNotify local target, so disable it */
1194 		priv->flags &= ~ID_P_HOST_NOTIFY;
1195 	}
1196 
1197 	ret = platform_get_irq(pdev, 0);
1198 	if (ret < 0)
1199 		goto out_pm_put;
1200 	priv->irq = ret;
1201 	ret = devm_request_irq(dev, priv->irq, irqhandler, irqflags, dev_name(dev), priv);
1202 	if (ret < 0) {
1203 		dev_err(dev, "cannot get irq %d\n", priv->irq);
1204 		goto out_pm_put;
1205 	}
1206 
1207 	platform_set_drvdata(pdev, priv);
1208 
1209 	ret = i2c_add_numbered_adapter(adap);
1210 	if (ret < 0)
1211 		goto out_pm_put;
1212 
1213 	if (priv->flags & ID_P_HOST_NOTIFY) {
1214 		priv->host_notify_client = i2c_new_slave_host_notify_device(adap);
1215 		if (IS_ERR(priv->host_notify_client)) {
1216 			ret = PTR_ERR(priv->host_notify_client);
1217 			goto out_del_device;
1218 		}
1219 	}
1220 
1221 	dev_info(dev, "probed\n");
1222 
1223 	return 0;
1224 
1225  out_del_device:
1226 	i2c_del_adapter(&priv->adap);
1227  out_pm_put:
1228 	if (priv->flags & ID_P_PM_BLOCKED)
1229 		pm_runtime_put(dev);
1230  out_pm_disable:
1231 	pm_runtime_disable(dev);
1232 	return ret;
1233 }
1234 
1235 static void rcar_i2c_remove(struct platform_device *pdev)
1236 {
1237 	struct rcar_i2c_priv *priv = platform_get_drvdata(pdev);
1238 	struct device *dev = &pdev->dev;
1239 
1240 	if (priv->host_notify_client)
1241 		i2c_free_slave_host_notify_device(priv->host_notify_client);
1242 	i2c_del_adapter(&priv->adap);
1243 	rcar_i2c_release_dma(priv);
1244 	if (priv->flags & ID_P_PM_BLOCKED)
1245 		pm_runtime_put(dev);
1246 	pm_runtime_disable(dev);
1247 }
1248 
1249 static int rcar_i2c_suspend(struct device *dev)
1250 {
1251 	struct rcar_i2c_priv *priv = dev_get_drvdata(dev);
1252 
1253 	i2c_mark_adapter_suspended(&priv->adap);
1254 	return 0;
1255 }
1256 
1257 static int rcar_i2c_resume(struct device *dev)
1258 {
1259 	struct rcar_i2c_priv *priv = dev_get_drvdata(dev);
1260 
1261 	i2c_mark_adapter_resumed(&priv->adap);
1262 	return 0;
1263 }
1264 
1265 static const struct dev_pm_ops rcar_i2c_pm_ops = {
1266 	NOIRQ_SYSTEM_SLEEP_PM_OPS(rcar_i2c_suspend, rcar_i2c_resume)
1267 };
1268 
1269 static struct platform_driver rcar_i2c_driver = {
1270 	.driver	= {
1271 		.name	= "i2c-rcar",
1272 		.of_match_table = rcar_i2c_dt_ids,
1273 		.pm	= pm_sleep_ptr(&rcar_i2c_pm_ops),
1274 	},
1275 	.probe		= rcar_i2c_probe,
1276 	.remove_new	= rcar_i2c_remove,
1277 };
1278 
1279 module_platform_driver(rcar_i2c_driver);
1280 
1281 MODULE_LICENSE("GPL v2");
1282 MODULE_DESCRIPTION("Renesas R-Car I2C bus driver");
1283 MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
1284