xref: /linux/drivers/i2c/busses/i2c-rcar.c (revision e6a901a00822659181c93c86d8bbc2a17779fddc)
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 
197 static void rcar_i2c_set_scl(struct i2c_adapter *adap, int val)
198 {
199 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
200 
201 	if (val)
202 		priv->recovery_icmcr |= FSCL;
203 	else
204 		priv->recovery_icmcr &= ~FSCL;
205 
206 	rcar_i2c_write(priv, ICMCR, priv->recovery_icmcr);
207 };
208 
209 static void rcar_i2c_set_sda(struct i2c_adapter *adap, int val)
210 {
211 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
212 
213 	if (val)
214 		priv->recovery_icmcr |= FSDA;
215 	else
216 		priv->recovery_icmcr &= ~FSDA;
217 
218 	rcar_i2c_write(priv, ICMCR, priv->recovery_icmcr);
219 };
220 
221 static int rcar_i2c_get_bus_free(struct i2c_adapter *adap)
222 {
223 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
224 
225 	return !(rcar_i2c_read(priv, ICMCR) & FSDA);
226 
227 };
228 
229 static struct i2c_bus_recovery_info rcar_i2c_bri = {
230 	.get_scl = rcar_i2c_get_scl,
231 	.set_scl = rcar_i2c_set_scl,
232 	.set_sda = rcar_i2c_set_sda,
233 	.get_bus_free = rcar_i2c_get_bus_free,
234 	.recover_bus = i2c_generic_scl_recovery,
235 };
236 static void rcar_i2c_init(struct rcar_i2c_priv *priv)
237 {
238 	/* reset master mode */
239 	rcar_i2c_write(priv, ICMIER, 0);
240 	rcar_i2c_write(priv, ICMCR, MDBS);
241 	rcar_i2c_write(priv, ICMSR, 0);
242 	/* start clock */
243 	if (priv->devtype < I2C_RCAR_GEN3) {
244 		rcar_i2c_write(priv, ICCCR, priv->icccr);
245 	} else {
246 		u32 icccr2 = CDFD | HLSE | SME;
247 
248 		if (priv->flags & ID_P_FMPLUS)
249 			icccr2 |= FMPE;
250 
251 		rcar_i2c_write(priv, ICCCR2, icccr2);
252 		rcar_i2c_write(priv, ICCCR, priv->icccr);
253 		rcar_i2c_write(priv, ICMPR, priv->smd);
254 		rcar_i2c_write(priv, ICHPR, priv->schd);
255 		rcar_i2c_write(priv, ICLPR, priv->scld);
256 		rcar_i2c_write(priv, ICFBSCR, TCYC17);
257 	}
258 }
259 
260 static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv)
261 {
262 	int ret;
263 	u32 val;
264 
265 	ret = readl_poll_timeout(priv->io + ICMCR, val, !(val & FSDA), 10,
266 				 priv->adap.timeout);
267 	if (ret) {
268 		/* Waiting did not help, try to recover */
269 		priv->recovery_icmcr = MDBS | OBPC | FSDA | FSCL;
270 		ret = i2c_recover_bus(&priv->adap);
271 	}
272 
273 	return ret;
274 }
275 
276 static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv)
277 {
278 	u32 cdf, round, ick, sum, scl, cdf_width;
279 	unsigned long rate;
280 	struct device *dev = rcar_i2c_priv_to_dev(priv);
281 	struct i2c_timings t = {
282 		.bus_freq_hz		= I2C_MAX_STANDARD_MODE_FREQ,
283 		.scl_fall_ns		= 35,
284 		.scl_rise_ns		= 200,
285 		.scl_int_delay_ns	= 50,
286 	};
287 
288 	/* Fall back to previously used values if not supplied */
289 	i2c_parse_fw_timings(dev, &t, false);
290 	priv->smd = RCAR_DEFAULT_SMD;
291 
292 	/*
293 	 * calculate SCL clock
294 	 * see
295 	 *	ICCCR (and ICCCR2 for Gen3+)
296 	 *
297 	 * ick	= clkp / (1 + CDF)
298 	 * SCL	= ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
299 	 *
300 	 * for Gen3+:
301 	 * SCL	= clkp / (8 + SMD * 2 + SCLD + SCHD +F[(ticf + tr + intd) * clkp])
302 	 *
303 	 * ick  : I2C internal clock < 20 MHz
304 	 * ticf : I2C SCL falling time
305 	 * tr   : I2C SCL rising  time
306 	 * intd : LSI internal delay
307 	 * clkp : peripheral_clk
308 	 * F[]  : integer up-valuation
309 	 */
310 	rate = clk_get_rate(priv->clk);
311 	cdf = rate / 20000000;
312 	cdf_width = (priv->devtype == I2C_RCAR_GEN1) ? 2 : 3;
313 	if (cdf >= 1U << cdf_width)
314 		goto err_no_val;
315 
316 	if (t.bus_freq_hz > I2C_MAX_FAST_MODE_FREQ && priv->devtype >= I2C_RCAR_GEN4)
317 		priv->flags |= ID_P_FMPLUS;
318 	else
319 		priv->flags &= ~ID_P_FMPLUS;
320 
321 	/* On Gen3+, we use cdf only for the filters, not as a SCL divider */
322 	ick = rate / (priv->devtype < I2C_RCAR_GEN3 ? (cdf + 1) : 1);
323 
324 	/*
325 	 * It is impossible to calculate a large scale number on u32. Separate it.
326 	 *
327 	 * F[(ticf + tr + intd) * ick] with sum = (ticf + tr + intd)
328 	 *  = F[sum * ick / 1000000000]
329 	 *  = F[(ick / 1000000) * sum / 1000]
330 	 */
331 	sum = t.scl_fall_ns + t.scl_rise_ns + t.scl_int_delay_ns;
332 	round = DIV_ROUND_CLOSEST(ick, 1000000);
333 	round = DIV_ROUND_CLOSEST(round * sum, 1000);
334 
335 	if (priv->devtype < I2C_RCAR_GEN3) {
336 		u32 scgd;
337 		/*
338 		 * SCL	= ick / (20 + 8 * SCGD + F[(ticf + tr + intd) * ick])
339 		 * 20 + 8 * SCGD + F[...] = ick / SCL
340 		 * SCGD = ((ick / SCL) - 20 - F[...]) / 8
341 		 * Result (= SCL) should be less than bus_speed for hardware safety
342 		 */
343 		scgd = DIV_ROUND_UP(ick, t.bus_freq_hz ?: 1);
344 		scgd = DIV_ROUND_UP(scgd - 20 - round, 8);
345 		scl = ick / (20 + 8 * scgd + round);
346 
347 		if (scgd > 0x3f)
348 			goto err_no_val;
349 
350 		dev_dbg(dev, "clk %u/%u(%lu), round %u, CDF: %u, SCGD: %u\n",
351 			scl, t.bus_freq_hz, rate, round, cdf, scgd);
352 
353 		priv->icccr = scgd << cdf_width | cdf;
354 	} else {
355 		u32 x, sum_ratio = RCAR_SCHD_RATIO + RCAR_SCLD_RATIO;
356 		/*
357 		 * SCLD/SCHD ratio and SMD default value are explained above
358 		 * where they are defined. With these definitions, we can compute
359 		 * x as a base value for the SCLD/SCHD ratio:
360 		 *
361 		 * SCL = clkp / (8 + 2 * SMD + SCLD + SCHD + F[(ticf + tr + intd) * clkp])
362 		 * SCL = clkp / (8 + 2 * SMD + RCAR_SCLD_RATIO * x
363 		 *		 + RCAR_SCHD_RATIO * x + F[...])
364 		 *
365 		 * with: sum_ratio = RCAR_SCLD_RATIO + RCAR_SCHD_RATIO
366 		 *
367 		 * SCL = clkp / (8 + 2 * smd + sum_ratio * x + F[...])
368 		 * 8 + 2 * smd + sum_ratio * x + F[...] = clkp / SCL
369 		 * x = ((clkp / SCL) - 8 - 2 * smd - F[...]) / sum_ratio
370 		 */
371 		x = DIV_ROUND_UP(rate, t.bus_freq_hz ?: 1);
372 		x = DIV_ROUND_UP(x - 8 - 2 * priv->smd - round, sum_ratio);
373 		scl = rate / (8 + 2 * priv->smd + sum_ratio * x + round);
374 
375 		if (x == 0 || x * RCAR_SCLD_RATIO > 0xffff)
376 			goto err_no_val;
377 
378 		priv->icccr = cdf;
379 		priv->schd = RCAR_SCHD_RATIO * x;
380 		priv->scld = RCAR_SCLD_RATIO * x;
381 		if (priv->smd >= priv->schd)
382 			priv->smd = priv->schd - 1;
383 
384 		dev_dbg(dev, "clk %u/%u(%lu), round %u, CDF: %u SCHD %u SCLD %u SMD %u\n",
385 			scl, t.bus_freq_hz, rate, round, cdf, priv->schd, priv->scld, priv->smd);
386 	}
387 
388 	return 0;
389 
390 err_no_val:
391 	dev_err(dev, "it is impossible to calculate best SCL\n");
392 	return -EINVAL;
393 }
394 
395 /*
396  * We don't have a test case but the HW engineers say that the write order of
397  * ICMSR and ICMCR depends on whether we issue START or REP_START. So, ICMSR
398  * handling is outside of this function. First messages clear ICMSR before this
399  * function, interrupt handlers clear the relevant bits after this function.
400  */
401 static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv)
402 {
403 	int read = !!rcar_i2c_is_recv(priv);
404 	bool rep_start = !(priv->flags & ID_REP_AFTER_RD);
405 
406 	priv->pos = 0;
407 	priv->flags &= ID_P_MASK;
408 
409 	if (priv->msgs_left == 1)
410 		priv->flags |= ID_LAST_MSG;
411 
412 	rcar_i2c_write(priv, ICMAR, i2c_8bit_addr_from_msg(priv->msg));
413 	if (priv->flags & ID_P_NOT_ATOMIC)
414 		rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND);
415 
416 	if (rep_start)
417 		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
418 }
419 
420 static void rcar_i2c_first_msg(struct rcar_i2c_priv *priv,
421 			       struct i2c_msg *msgs, int num)
422 {
423 	priv->msg = msgs;
424 	priv->msgs_left = num;
425 	rcar_i2c_write(priv, ICMSR, 0); /* must be before preparing msg */
426 	rcar_i2c_prepare_msg(priv);
427 }
428 
429 static void rcar_i2c_next_msg(struct rcar_i2c_priv *priv)
430 {
431 	priv->msg++;
432 	priv->msgs_left--;
433 	rcar_i2c_prepare_msg(priv);
434 	/* ICMSR handling must come afterwards in the irq handler */
435 }
436 
437 static void rcar_i2c_cleanup_dma(struct rcar_i2c_priv *priv, bool terminate)
438 {
439 	struct dma_chan *chan = priv->dma_direction == DMA_FROM_DEVICE
440 		? priv->dma_rx : priv->dma_tx;
441 
442 	/* only allowed from thread context! */
443 	if (terminate)
444 		dmaengine_terminate_sync(chan);
445 
446 	dma_unmap_single(chan->device->dev, sg_dma_address(&priv->sg),
447 			 sg_dma_len(&priv->sg), priv->dma_direction);
448 
449 	/* Gen3+ can only do one RXDMA per transfer and we just completed it */
450 	if (priv->devtype >= I2C_RCAR_GEN3 &&
451 	    priv->dma_direction == DMA_FROM_DEVICE)
452 		priv->flags |= ID_P_NO_RXDMA;
453 
454 	priv->dma_direction = DMA_NONE;
455 
456 	/* Disable DMA Master Received/Transmitted, must be last! */
457 	rcar_i2c_write(priv, ICDMAER, 0);
458 }
459 
460 static void rcar_i2c_dma_callback(void *data)
461 {
462 	struct rcar_i2c_priv *priv = data;
463 
464 	priv->pos += sg_dma_len(&priv->sg);
465 
466 	rcar_i2c_cleanup_dma(priv, false);
467 }
468 
469 static bool rcar_i2c_dma(struct rcar_i2c_priv *priv)
470 {
471 	struct device *dev = rcar_i2c_priv_to_dev(priv);
472 	struct i2c_msg *msg = priv->msg;
473 	bool read = msg->flags & I2C_M_RD;
474 	enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
475 	struct dma_chan *chan = read ? priv->dma_rx : priv->dma_tx;
476 	struct dma_async_tx_descriptor *txdesc;
477 	dma_addr_t dma_addr;
478 	dma_cookie_t cookie;
479 	unsigned char *buf;
480 	int len;
481 
482 	/* Do various checks to see if DMA is feasible at all */
483 	if (!(priv->flags & ID_P_NOT_ATOMIC) || IS_ERR(chan) || msg->len < RCAR_MIN_DMA_LEN ||
484 	    !(msg->flags & I2C_M_DMA_SAFE) || (read && priv->flags & ID_P_NO_RXDMA))
485 		return false;
486 
487 	if (read) {
488 		/*
489 		 * The last two bytes needs to be fetched using PIO in
490 		 * order for the STOP phase to work.
491 		 */
492 		buf = priv->msg->buf;
493 		len = priv->msg->len - 2;
494 	} else {
495 		/*
496 		 * First byte in message was sent using PIO.
497 		 */
498 		buf = priv->msg->buf + 1;
499 		len = priv->msg->len - 1;
500 	}
501 
502 	dma_addr = dma_map_single(chan->device->dev, buf, len, dir);
503 	if (dma_mapping_error(chan->device->dev, dma_addr)) {
504 		dev_dbg(dev, "dma map failed, using PIO\n");
505 		return false;
506 	}
507 
508 	sg_dma_len(&priv->sg) = len;
509 	sg_dma_address(&priv->sg) = dma_addr;
510 
511 	priv->dma_direction = dir;
512 
513 	txdesc = dmaengine_prep_slave_sg(chan, &priv->sg, 1,
514 					 read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
515 					 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
516 	if (!txdesc) {
517 		dev_dbg(dev, "dma prep slave sg failed, using PIO\n");
518 		rcar_i2c_cleanup_dma(priv, false);
519 		return false;
520 	}
521 
522 	txdesc->callback = rcar_i2c_dma_callback;
523 	txdesc->callback_param = priv;
524 
525 	cookie = dmaengine_submit(txdesc);
526 	if (dma_submit_error(cookie)) {
527 		dev_dbg(dev, "submitting dma failed, using PIO\n");
528 		rcar_i2c_cleanup_dma(priv, false);
529 		return false;
530 	}
531 
532 	/* Enable DMA Master Received/Transmitted */
533 	if (read)
534 		rcar_i2c_write(priv, ICDMAER, RMDMAE);
535 	else
536 		rcar_i2c_write(priv, ICDMAER, TMDMAE);
537 
538 	dma_async_issue_pending(chan);
539 	return true;
540 }
541 
542 static void rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr)
543 {
544 	struct i2c_msg *msg = priv->msg;
545 	u32 irqs_to_clear = MDE;
546 
547 	/* FIXME: sometimes, unknown interrupt happened. Do nothing */
548 	if (!(msr & MDE))
549 		return;
550 
551 	if (msr & MAT)
552 		irqs_to_clear |= MAT;
553 
554 	/* Check if DMA can be enabled and take over */
555 	if (priv->pos == 1 && rcar_i2c_dma(priv))
556 		return;
557 
558 	if (priv->pos < msg->len) {
559 		/*
560 		 * Prepare next data to ICRXTX register.
561 		 * This data will go to _SHIFT_ register.
562 		 *
563 		 *    *
564 		 * [ICRXTX] -> [SHIFT] -> [I2C bus]
565 		 */
566 		rcar_i2c_write(priv, ICRXTX, msg->buf[priv->pos]);
567 		priv->pos++;
568 	} else {
569 		/*
570 		 * The last data was pushed to ICRXTX on _PREV_ empty irq.
571 		 * It is on _SHIFT_ register, and will sent to I2C bus.
572 		 *
573 		 *		  *
574 		 * [ICRXTX] -> [SHIFT] -> [I2C bus]
575 		 */
576 
577 		if (priv->flags & ID_LAST_MSG)
578 			/*
579 			 * If current msg is the _LAST_ msg,
580 			 * prepare stop condition here.
581 			 * ID_DONE will be set on STOP irq.
582 			 */
583 			rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
584 		else
585 			rcar_i2c_next_msg(priv);
586 	}
587 
588 	rcar_i2c_clear_irq(priv, irqs_to_clear);
589 }
590 
591 static void rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr)
592 {
593 	struct i2c_msg *msg = priv->msg;
594 	bool recv_len_init = priv->pos == 0 && msg->flags & I2C_M_RECV_LEN;
595 	u32 irqs_to_clear = MDR;
596 
597 	/* FIXME: sometimes, unknown interrupt happened. Do nothing */
598 	if (!(msr & MDR))
599 		return;
600 
601 	if (msr & MAT) {
602 		irqs_to_clear |= MAT;
603 		/*
604 		 * Address transfer phase finished, but no data at this point.
605 		 * Try to use DMA to receive data.
606 		 */
607 		rcar_i2c_dma(priv);
608 	} else if (priv->pos < msg->len) {
609 		/* get received data */
610 		u8 data = rcar_i2c_read(priv, ICRXTX);
611 
612 		msg->buf[priv->pos] = data;
613 		if (recv_len_init) {
614 			if (data == 0 || data > I2C_SMBUS_BLOCK_MAX) {
615 				priv->flags |= ID_DONE | ID_EPROTO;
616 				return;
617 			}
618 			msg->len += msg->buf[0];
619 			/* Enough data for DMA? */
620 			if (rcar_i2c_dma(priv))
621 				return;
622 			/* new length after RECV_LEN now properly initialized */
623 			recv_len_init = false;
624 		}
625 		priv->pos++;
626 	}
627 
628 	/*
629 	 * If next received data is the _LAST_ and we are not waiting for a new
630 	 * length because of RECV_LEN, then go to a new phase.
631 	 */
632 	if (priv->pos + 1 == msg->len && !recv_len_init) {
633 		if (priv->flags & ID_LAST_MSG) {
634 			rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
635 		} else {
636 			rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
637 			priv->flags |= ID_REP_AFTER_RD;
638 		}
639 	}
640 
641 	if (priv->pos == msg->len && !(priv->flags & ID_LAST_MSG))
642 		rcar_i2c_next_msg(priv);
643 
644 	rcar_i2c_clear_irq(priv, irqs_to_clear);
645 }
646 
647 static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
648 {
649 	u32 ssr_raw, ssr_filtered;
650 	u8 value;
651 
652 	ssr_raw = rcar_i2c_read(priv, ICSSR) & 0xff;
653 	ssr_filtered = ssr_raw & rcar_i2c_read(priv, ICSIER);
654 
655 	if (!ssr_filtered)
656 		return false;
657 
658 	/* address detected */
659 	if (ssr_filtered & SAR) {
660 		/* read or write request */
661 		if (ssr_raw & STM) {
662 			i2c_slave_event(priv->slave, I2C_SLAVE_READ_REQUESTED, &value);
663 			rcar_i2c_write(priv, ICRXTX, value);
664 			rcar_i2c_write(priv, ICSIER, SDE | SSR | SAR);
665 		} else {
666 			i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
667 			rcar_i2c_read(priv, ICRXTX);	/* dummy read */
668 			rcar_i2c_write(priv, ICSIER, SDR | SSR | SAR);
669 		}
670 
671 		/* Clear SSR, too, because of old STOPs to other clients than us */
672 		rcar_i2c_write(priv, ICSSR, ~(SAR | SSR) & 0xff);
673 	}
674 
675 	/* master sent stop */
676 	if (ssr_filtered & SSR) {
677 		i2c_slave_event(priv->slave, I2C_SLAVE_STOP, &value);
678 		rcar_i2c_write(priv, ICSCR, SIE | SDBS); /* clear our NACK */
679 		rcar_i2c_write(priv, ICSIER, SAR);
680 		rcar_i2c_write(priv, ICSSR, ~SSR & 0xff);
681 	}
682 
683 	/* master wants to write to us */
684 	if (ssr_filtered & SDR) {
685 		int ret;
686 
687 		value = rcar_i2c_read(priv, ICRXTX);
688 		ret = i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
689 		/* Send NACK in case of error */
690 		rcar_i2c_write(priv, ICSCR, SIE | SDBS | (ret < 0 ? FNA : 0));
691 		rcar_i2c_write(priv, ICSSR, ~SDR & 0xff);
692 	}
693 
694 	/* master wants to read from us */
695 	if (ssr_filtered & SDE) {
696 		i2c_slave_event(priv->slave, I2C_SLAVE_READ_PROCESSED, &value);
697 		rcar_i2c_write(priv, ICRXTX, value);
698 		rcar_i2c_write(priv, ICSSR, ~SDE & 0xff);
699 	}
700 
701 	return true;
702 }
703 
704 /*
705  * This driver has a lock-free design because there are IP cores (at least
706  * R-Car Gen2) which have an inherent race condition in their hardware design.
707  * There, we need to switch to RCAR_BUS_PHASE_DATA as soon as possible after
708  * the interrupt was generated, otherwise an unwanted repeated message gets
709  * generated. It turned out that taking a spinlock at the beginning of the ISR
710  * was already causing repeated messages. Thus, this driver was converted to
711  * the now lockless behaviour. Please keep this in mind when hacking the driver.
712  * R-Car Gen3 seems to have this fixed but earlier versions than R-Car Gen2 are
713  * likely affected. Therefore, we have different interrupt handler entries.
714  */
715 static irqreturn_t rcar_i2c_irq(int irq, struct rcar_i2c_priv *priv, u32 msr)
716 {
717 	if (!msr) {
718 		if (rcar_i2c_slave_irq(priv))
719 			return IRQ_HANDLED;
720 
721 		return IRQ_NONE;
722 	}
723 
724 	/* Arbitration lost */
725 	if (msr & MAL) {
726 		priv->flags |= ID_DONE | ID_ARBLOST;
727 		goto out;
728 	}
729 
730 	/* Nack */
731 	if (msr & MNR) {
732 		/* HW automatically sends STOP after received NACK */
733 		if (priv->flags & ID_P_NOT_ATOMIC)
734 			rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP);
735 		priv->flags |= ID_NACK;
736 		goto out;
737 	}
738 
739 	/* Stop */
740 	if (msr & MST) {
741 		priv->msgs_left--; /* The last message also made it */
742 		priv->flags |= ID_DONE;
743 		goto out;
744 	}
745 
746 	if (rcar_i2c_is_recv(priv))
747 		rcar_i2c_irq_recv(priv, msr);
748 	else
749 		rcar_i2c_irq_send(priv, msr);
750 
751 out:
752 	if (priv->flags & ID_DONE) {
753 		rcar_i2c_write(priv, ICMIER, 0);
754 		rcar_i2c_write(priv, ICMSR, 0);
755 		if (priv->flags & ID_P_NOT_ATOMIC)
756 			wake_up(&priv->wait);
757 	}
758 
759 	return IRQ_HANDLED;
760 }
761 
762 static irqreturn_t rcar_i2c_gen2_irq(int irq, void *ptr)
763 {
764 	struct rcar_i2c_priv *priv = ptr;
765 	u32 msr;
766 
767 	/* Clear START or STOP immediately, except for REPSTART after read */
768 	if (likely(!(priv->flags & ID_REP_AFTER_RD)))
769 		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
770 
771 	/* Only handle interrupts that are currently enabled */
772 	msr = rcar_i2c_read(priv, ICMSR);
773 	if (priv->flags & ID_P_NOT_ATOMIC)
774 		msr &= rcar_i2c_read(priv, ICMIER);
775 
776 	return rcar_i2c_irq(irq, priv, msr);
777 }
778 
779 static irqreturn_t rcar_i2c_gen3_irq(int irq, void *ptr)
780 {
781 	struct rcar_i2c_priv *priv = ptr;
782 	u32 msr;
783 
784 	/* Only handle interrupts that are currently enabled */
785 	msr = rcar_i2c_read(priv, ICMSR);
786 	if (priv->flags & ID_P_NOT_ATOMIC)
787 		msr &= rcar_i2c_read(priv, ICMIER);
788 
789 	/*
790 	 * Clear START or STOP immediately, except for REPSTART after read or
791 	 * if a spurious interrupt was detected.
792 	 */
793 	if (likely(!(priv->flags & ID_REP_AFTER_RD) && msr))
794 		rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
795 
796 	return rcar_i2c_irq(irq, priv, msr);
797 }
798 
799 static struct dma_chan *rcar_i2c_request_dma_chan(struct device *dev,
800 					enum dma_transfer_direction dir,
801 					dma_addr_t port_addr)
802 {
803 	struct dma_chan *chan;
804 	struct dma_slave_config cfg;
805 	char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
806 	int ret;
807 
808 	chan = dma_request_chan(dev, chan_name);
809 	if (IS_ERR(chan)) {
810 		dev_dbg(dev, "request_channel failed for %s (%ld)\n",
811 			chan_name, PTR_ERR(chan));
812 		return chan;
813 	}
814 
815 	memset(&cfg, 0, sizeof(cfg));
816 	cfg.direction = dir;
817 	if (dir == DMA_MEM_TO_DEV) {
818 		cfg.dst_addr = port_addr;
819 		cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
820 	} else {
821 		cfg.src_addr = port_addr;
822 		cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
823 	}
824 
825 	ret = dmaengine_slave_config(chan, &cfg);
826 	if (ret) {
827 		dev_dbg(dev, "slave_config failed for %s (%d)\n",
828 			chan_name, ret);
829 		dma_release_channel(chan);
830 		return ERR_PTR(ret);
831 	}
832 
833 	dev_dbg(dev, "got DMA channel for %s\n", chan_name);
834 	return chan;
835 }
836 
837 static void rcar_i2c_request_dma(struct rcar_i2c_priv *priv,
838 				 struct i2c_msg *msg)
839 {
840 	struct device *dev = rcar_i2c_priv_to_dev(priv);
841 	bool read;
842 	struct dma_chan *chan;
843 	enum dma_transfer_direction dir;
844 
845 	read = msg->flags & I2C_M_RD;
846 
847 	chan = read ? priv->dma_rx : priv->dma_tx;
848 	if (PTR_ERR(chan) != -EPROBE_DEFER)
849 		return;
850 
851 	dir = read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV;
852 	chan = rcar_i2c_request_dma_chan(dev, dir, priv->res->start + ICRXTX);
853 
854 	if (read)
855 		priv->dma_rx = chan;
856 	else
857 		priv->dma_tx = chan;
858 }
859 
860 static void rcar_i2c_release_dma(struct rcar_i2c_priv *priv)
861 {
862 	if (!IS_ERR(priv->dma_tx)) {
863 		dma_release_channel(priv->dma_tx);
864 		priv->dma_tx = ERR_PTR(-EPROBE_DEFER);
865 	}
866 
867 	if (!IS_ERR(priv->dma_rx)) {
868 		dma_release_channel(priv->dma_rx);
869 		priv->dma_rx = ERR_PTR(-EPROBE_DEFER);
870 	}
871 }
872 
873 /* I2C is a special case, we need to poll the status of a reset */
874 static int rcar_i2c_do_reset(struct rcar_i2c_priv *priv)
875 {
876 	int ret;
877 
878 	ret = reset_control_reset(priv->rstc);
879 	if (ret)
880 		return ret;
881 
882 	return read_poll_timeout_atomic(reset_control_status, ret, ret == 0, 1,
883 					100, false, priv->rstc);
884 }
885 
886 static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
887 				struct i2c_msg *msgs,
888 				int num)
889 {
890 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
891 	struct device *dev = rcar_i2c_priv_to_dev(priv);
892 	int i, ret;
893 	long time_left;
894 
895 	priv->flags |= ID_P_NOT_ATOMIC;
896 
897 	pm_runtime_get_sync(dev);
898 
899 	/* Check bus state before init otherwise bus busy info will be lost */
900 	ret = rcar_i2c_bus_barrier(priv);
901 	if (ret < 0)
902 		goto out;
903 
904 	/* Gen3+ needs a reset. That also allows RXDMA once */
905 	if (priv->devtype >= I2C_RCAR_GEN3) {
906 		priv->flags &= ~ID_P_NO_RXDMA;
907 		ret = rcar_i2c_do_reset(priv);
908 		if (ret)
909 			goto out;
910 	}
911 
912 	rcar_i2c_init(priv);
913 
914 	for (i = 0; i < num; i++)
915 		rcar_i2c_request_dma(priv, msgs + i);
916 
917 	rcar_i2c_first_msg(priv, msgs, num);
918 
919 	time_left = wait_event_timeout(priv->wait, priv->flags & ID_DONE,
920 				     num * adap->timeout);
921 
922 	/* cleanup DMA if it couldn't complete properly due to an error */
923 	if (priv->dma_direction != DMA_NONE)
924 		rcar_i2c_cleanup_dma(priv, true);
925 
926 	if (!time_left) {
927 		rcar_i2c_init(priv);
928 		ret = -ETIMEDOUT;
929 	} else if (priv->flags & ID_NACK) {
930 		ret = -ENXIO;
931 	} else if (priv->flags & ID_ARBLOST) {
932 		ret = -EAGAIN;
933 	} else if (priv->flags & ID_EPROTO) {
934 		ret = -EPROTO;
935 	} else {
936 		ret = num - priv->msgs_left; /* The number of transfer */
937 	}
938 out:
939 	pm_runtime_put(dev);
940 
941 	if (ret < 0 && ret != -ENXIO)
942 		dev_err(dev, "error %d : %x\n", ret, priv->flags);
943 
944 	return ret;
945 }
946 
947 static int rcar_i2c_master_xfer_atomic(struct i2c_adapter *adap,
948 				struct i2c_msg *msgs,
949 				int num)
950 {
951 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
952 	struct device *dev = rcar_i2c_priv_to_dev(priv);
953 	unsigned long j;
954 	bool time_left;
955 	int ret;
956 
957 	priv->flags &= ~ID_P_NOT_ATOMIC;
958 
959 	pm_runtime_get_sync(dev);
960 
961 	/* Check bus state before init otherwise bus busy info will be lost */
962 	ret = rcar_i2c_bus_barrier(priv);
963 	if (ret < 0)
964 		goto out;
965 
966 	rcar_i2c_init(priv);
967 	rcar_i2c_first_msg(priv, msgs, num);
968 
969 	j = jiffies + num * adap->timeout;
970 	do {
971 		u32 msr = rcar_i2c_read(priv, ICMSR);
972 
973 		msr &= (rcar_i2c_is_recv(priv) ? RCAR_IRQ_RECV : RCAR_IRQ_SEND) | RCAR_IRQ_STOP;
974 
975 		if (msr) {
976 			if (priv->devtype < I2C_RCAR_GEN3)
977 				rcar_i2c_gen2_irq(0, priv);
978 			else
979 				rcar_i2c_gen3_irq(0, priv);
980 		}
981 
982 		time_left = time_before_eq(jiffies, j);
983 	} while (!(priv->flags & ID_DONE) && time_left);
984 
985 	if (!time_left) {
986 		rcar_i2c_init(priv);
987 		ret = -ETIMEDOUT;
988 	} else if (priv->flags & ID_NACK) {
989 		ret = -ENXIO;
990 	} else if (priv->flags & ID_ARBLOST) {
991 		ret = -EAGAIN;
992 	} else if (priv->flags & ID_EPROTO) {
993 		ret = -EPROTO;
994 	} else {
995 		ret = num - priv->msgs_left; /* The number of transfer */
996 	}
997 out:
998 	pm_runtime_put(dev);
999 
1000 	if (ret < 0 && ret != -ENXIO)
1001 		dev_err(dev, "error %d : %x\n", ret, priv->flags);
1002 
1003 	return ret;
1004 }
1005 
1006 static int rcar_reg_slave(struct i2c_client *slave)
1007 {
1008 	struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
1009 
1010 	if (priv->slave)
1011 		return -EBUSY;
1012 
1013 	if (slave->flags & I2C_CLIENT_TEN)
1014 		return -EAFNOSUPPORT;
1015 
1016 	/* Keep device active for slave address detection logic */
1017 	pm_runtime_get_sync(rcar_i2c_priv_to_dev(priv));
1018 
1019 	priv->slave = slave;
1020 	rcar_i2c_write(priv, ICSAR, slave->addr);
1021 	rcar_i2c_write(priv, ICSSR, 0);
1022 	rcar_i2c_write(priv, ICSIER, SAR);
1023 	rcar_i2c_write(priv, ICSCR, SIE | SDBS);
1024 
1025 	return 0;
1026 }
1027 
1028 static int rcar_unreg_slave(struct i2c_client *slave)
1029 {
1030 	struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
1031 
1032 	WARN_ON(!priv->slave);
1033 
1034 	/* ensure no irq is running before clearing ptr */
1035 	disable_irq(priv->irq);
1036 	rcar_i2c_write(priv, ICSIER, 0);
1037 	rcar_i2c_write(priv, ICSSR, 0);
1038 	enable_irq(priv->irq);
1039 	rcar_i2c_write(priv, ICSCR, SDBS);
1040 	rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */
1041 
1042 	priv->slave = NULL;
1043 
1044 	pm_runtime_put(rcar_i2c_priv_to_dev(priv));
1045 
1046 	return 0;
1047 }
1048 
1049 static u32 rcar_i2c_func(struct i2c_adapter *adap)
1050 {
1051 	struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
1052 
1053 	/*
1054 	 * This HW can't do:
1055 	 * I2C_SMBUS_QUICK (setting FSB during START didn't work)
1056 	 * I2C_M_NOSTART (automatically sends address after START)
1057 	 * I2C_M_IGNORE_NAK (automatically sends STOP after NAK)
1058 	 */
1059 	u32 func = I2C_FUNC_I2C | I2C_FUNC_SLAVE |
1060 		   (I2C_FUNC_SMBUS_EMUL_ALL & ~I2C_FUNC_SMBUS_QUICK);
1061 
1062 	if (priv->flags & ID_P_HOST_NOTIFY)
1063 		func |= I2C_FUNC_SMBUS_HOST_NOTIFY;
1064 
1065 	return func;
1066 }
1067 
1068 static const struct i2c_algorithm rcar_i2c_algo = {
1069 	.master_xfer	= rcar_i2c_master_xfer,
1070 	.master_xfer_atomic = rcar_i2c_master_xfer_atomic,
1071 	.functionality	= rcar_i2c_func,
1072 	.reg_slave	= rcar_reg_slave,
1073 	.unreg_slave	= rcar_unreg_slave,
1074 };
1075 
1076 static const struct i2c_adapter_quirks rcar_i2c_quirks = {
1077 	.flags = I2C_AQ_NO_ZERO_LEN,
1078 };
1079 
1080 static const struct of_device_id rcar_i2c_dt_ids[] = {
1081 	{ .compatible = "renesas,i2c-r8a7778", .data = (void *)I2C_RCAR_GEN1 },
1082 	{ .compatible = "renesas,i2c-r8a7779", .data = (void *)I2C_RCAR_GEN1 },
1083 	{ .compatible = "renesas,i2c-r8a7790", .data = (void *)I2C_RCAR_GEN2 },
1084 	{ .compatible = "renesas,i2c-r8a7791", .data = (void *)I2C_RCAR_GEN2 },
1085 	{ .compatible = "renesas,i2c-r8a7792", .data = (void *)I2C_RCAR_GEN2 },
1086 	{ .compatible = "renesas,i2c-r8a7793", .data = (void *)I2C_RCAR_GEN2 },
1087 	{ .compatible = "renesas,i2c-r8a7794", .data = (void *)I2C_RCAR_GEN2 },
1088 	{ .compatible = "renesas,i2c-r8a7795", .data = (void *)I2C_RCAR_GEN3 },
1089 	{ .compatible = "renesas,i2c-r8a7796", .data = (void *)I2C_RCAR_GEN3 },
1090 	/* S4 has no FM+ bit */
1091 	{ .compatible = "renesas,i2c-r8a779f0", .data = (void *)I2C_RCAR_GEN3 },
1092 	{ .compatible = "renesas,rcar-gen1-i2c", .data = (void *)I2C_RCAR_GEN1 },
1093 	{ .compatible = "renesas,rcar-gen2-i2c", .data = (void *)I2C_RCAR_GEN2 },
1094 	{ .compatible = "renesas,rcar-gen3-i2c", .data = (void *)I2C_RCAR_GEN3 },
1095 	{ .compatible = "renesas,rcar-gen4-i2c", .data = (void *)I2C_RCAR_GEN4 },
1096 	{},
1097 };
1098 MODULE_DEVICE_TABLE(of, rcar_i2c_dt_ids);
1099 
1100 static int rcar_i2c_probe(struct platform_device *pdev)
1101 {
1102 	struct rcar_i2c_priv *priv;
1103 	struct i2c_adapter *adap;
1104 	struct device *dev = &pdev->dev;
1105 	unsigned long irqflags = 0;
1106 	irqreturn_t (*irqhandler)(int irq, void *ptr) = rcar_i2c_gen3_irq;
1107 	int ret;
1108 
1109 	/* Otherwise logic will break because some bytes must always use PIO */
1110 	BUILD_BUG_ON_MSG(RCAR_MIN_DMA_LEN < 3, "Invalid min DMA length");
1111 
1112 	priv = devm_kzalloc(dev, sizeof(struct rcar_i2c_priv), GFP_KERNEL);
1113 	if (!priv)
1114 		return -ENOMEM;
1115 
1116 	priv->clk = devm_clk_get(dev, NULL);
1117 	if (IS_ERR(priv->clk)) {
1118 		dev_err(dev, "cannot get clock\n");
1119 		return PTR_ERR(priv->clk);
1120 	}
1121 
1122 	priv->io = devm_platform_get_and_ioremap_resource(pdev, 0, &priv->res);
1123 	if (IS_ERR(priv->io))
1124 		return PTR_ERR(priv->io);
1125 
1126 	priv->devtype = (enum rcar_i2c_type)of_device_get_match_data(dev);
1127 	init_waitqueue_head(&priv->wait);
1128 
1129 	adap = &priv->adap;
1130 	adap->nr = pdev->id;
1131 	adap->algo = &rcar_i2c_algo;
1132 	adap->class = I2C_CLASS_DEPRECATED;
1133 	adap->retries = 3;
1134 	adap->dev.parent = dev;
1135 	adap->dev.of_node = dev->of_node;
1136 	adap->bus_recovery_info = &rcar_i2c_bri;
1137 	adap->quirks = &rcar_i2c_quirks;
1138 	i2c_set_adapdata(adap, priv);
1139 	strscpy(adap->name, pdev->name, sizeof(adap->name));
1140 
1141 	/* Init DMA */
1142 	sg_init_table(&priv->sg, 1);
1143 	priv->dma_direction = DMA_NONE;
1144 	priv->dma_rx = priv->dma_tx = ERR_PTR(-EPROBE_DEFER);
1145 
1146 	/* Activate device for clock calculation */
1147 	pm_runtime_enable(dev);
1148 	pm_runtime_get_sync(dev);
1149 	ret = rcar_i2c_clock_calculate(priv);
1150 	if (ret < 0) {
1151 		pm_runtime_put(dev);
1152 		goto out_pm_disable;
1153 	}
1154 
1155 	rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */
1156 
1157 	if (priv->devtype < I2C_RCAR_GEN3) {
1158 		irqflags |= IRQF_NO_THREAD;
1159 		irqhandler = rcar_i2c_gen2_irq;
1160 	}
1161 
1162 	/* Stay always active when multi-master to keep arbitration working */
1163 	if (of_property_read_bool(dev->of_node, "multi-master"))
1164 		priv->flags |= ID_P_PM_BLOCKED;
1165 	else
1166 		pm_runtime_put(dev);
1167 
1168 	if (of_property_read_bool(dev->of_node, "smbus"))
1169 		priv->flags |= ID_P_HOST_NOTIFY;
1170 
1171 	if (priv->devtype >= I2C_RCAR_GEN3) {
1172 		priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
1173 		if (IS_ERR(priv->rstc)) {
1174 			ret = PTR_ERR(priv->rstc);
1175 			goto out_pm_put;
1176 		}
1177 
1178 		ret = reset_control_status(priv->rstc);
1179 		if (ret < 0)
1180 			goto out_pm_put;
1181 	}
1182 
1183 	ret = platform_get_irq(pdev, 0);
1184 	if (ret < 0)
1185 		goto out_pm_put;
1186 	priv->irq = ret;
1187 	ret = devm_request_irq(dev, priv->irq, irqhandler, irqflags, dev_name(dev), priv);
1188 	if (ret < 0) {
1189 		dev_err(dev, "cannot get irq %d\n", priv->irq);
1190 		goto out_pm_put;
1191 	}
1192 
1193 	platform_set_drvdata(pdev, priv);
1194 
1195 	ret = i2c_add_numbered_adapter(adap);
1196 	if (ret < 0)
1197 		goto out_pm_put;
1198 
1199 	if (priv->flags & ID_P_HOST_NOTIFY) {
1200 		priv->host_notify_client = i2c_new_slave_host_notify_device(adap);
1201 		if (IS_ERR(priv->host_notify_client)) {
1202 			ret = PTR_ERR(priv->host_notify_client);
1203 			goto out_del_device;
1204 		}
1205 	}
1206 
1207 	dev_info(dev, "probed\n");
1208 
1209 	return 0;
1210 
1211  out_del_device:
1212 	i2c_del_adapter(&priv->adap);
1213  out_pm_put:
1214 	if (priv->flags & ID_P_PM_BLOCKED)
1215 		pm_runtime_put(dev);
1216  out_pm_disable:
1217 	pm_runtime_disable(dev);
1218 	return ret;
1219 }
1220 
1221 static void rcar_i2c_remove(struct platform_device *pdev)
1222 {
1223 	struct rcar_i2c_priv *priv = platform_get_drvdata(pdev);
1224 	struct device *dev = &pdev->dev;
1225 
1226 	if (priv->host_notify_client)
1227 		i2c_free_slave_host_notify_device(priv->host_notify_client);
1228 	i2c_del_adapter(&priv->adap);
1229 	rcar_i2c_release_dma(priv);
1230 	if (priv->flags & ID_P_PM_BLOCKED)
1231 		pm_runtime_put(dev);
1232 	pm_runtime_disable(dev);
1233 }
1234 
1235 static int rcar_i2c_suspend(struct device *dev)
1236 {
1237 	struct rcar_i2c_priv *priv = dev_get_drvdata(dev);
1238 
1239 	i2c_mark_adapter_suspended(&priv->adap);
1240 	return 0;
1241 }
1242 
1243 static int rcar_i2c_resume(struct device *dev)
1244 {
1245 	struct rcar_i2c_priv *priv = dev_get_drvdata(dev);
1246 
1247 	i2c_mark_adapter_resumed(&priv->adap);
1248 	return 0;
1249 }
1250 
1251 static const struct dev_pm_ops rcar_i2c_pm_ops = {
1252 	NOIRQ_SYSTEM_SLEEP_PM_OPS(rcar_i2c_suspend, rcar_i2c_resume)
1253 };
1254 
1255 static struct platform_driver rcar_i2c_driver = {
1256 	.driver	= {
1257 		.name	= "i2c-rcar",
1258 		.of_match_table = rcar_i2c_dt_ids,
1259 		.pm	= pm_sleep_ptr(&rcar_i2c_pm_ops),
1260 	},
1261 	.probe		= rcar_i2c_probe,
1262 	.remove_new	= rcar_i2c_remove,
1263 };
1264 
1265 module_platform_driver(rcar_i2c_driver);
1266 
1267 MODULE_LICENSE("GPL v2");
1268 MODULE_DESCRIPTION("Renesas R-Car I2C bus driver");
1269 MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
1270