1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Driver for the Renesas R-Car I2C unit
4 *
5 * Copyright (C) 2014-15 Wolfram Sang <wsa@sang-engineering.com>
6 * Copyright (C) 2011-2015 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/i2c.h>
23 #include <linux/kernel.h>
24 #include <linux/module.h>
25 #include <linux/of_device.h>
26 #include <linux/platform_device.h>
27 #include <linux/pm_runtime.h>
28 #include <linux/reset.h>
29 #include <linux/slab.h>
30
31 /* register offsets */
32 #define ICSCR 0x00 /* slave ctrl */
33 #define ICMCR 0x04 /* master ctrl */
34 #define ICSSR 0x08 /* slave status */
35 #define ICMSR 0x0C /* master status */
36 #define ICSIER 0x10 /* slave irq enable */
37 #define ICMIER 0x14 /* master irq enable */
38 #define ICCCR 0x18 /* clock dividers */
39 #define ICSAR 0x1C /* slave address */
40 #define ICMAR 0x20 /* master address */
41 #define ICRXTX 0x24 /* data port */
42 #define ICDMAER 0x3c /* DMA enable */
43 #define ICFBSCR 0x38 /* first bit setup cycle */
44
45 /* ICSCR */
46 #define SDBS (1 << 3) /* slave data buffer select */
47 #define SIE (1 << 2) /* slave interface enable */
48 #define GCAE (1 << 1) /* general call address enable */
49 #define FNA (1 << 0) /* forced non acknowledgment */
50
51 /* ICMCR */
52 #define MDBS (1 << 7) /* non-fifo mode switch */
53 #define FSCL (1 << 6) /* override SCL pin */
54 #define FSDA (1 << 5) /* override SDA pin */
55 #define OBPC (1 << 4) /* override pins */
56 #define MIE (1 << 3) /* master if enable */
57 #define TSBE (1 << 2)
58 #define FSB (1 << 1) /* force stop bit */
59 #define ESG (1 << 0) /* enable start bit gen */
60
61 /* ICSSR (also for ICSIER) */
62 #define GCAR (1 << 6) /* general call received */
63 #define STM (1 << 5) /* slave transmit mode */
64 #define SSR (1 << 4) /* stop received */
65 #define SDE (1 << 3) /* slave data empty */
66 #define SDT (1 << 2) /* slave data transmitted */
67 #define SDR (1 << 1) /* slave data received */
68 #define SAR (1 << 0) /* slave addr received */
69
70 /* ICMSR (also for ICMIE) */
71 #define MNR (1 << 6) /* nack received */
72 #define MAL (1 << 5) /* arbitration lost */
73 #define MST (1 << 4) /* sent a stop */
74 #define MDE (1 << 3)
75 #define MDT (1 << 2)
76 #define MDR (1 << 1)
77 #define MAT (1 << 0) /* slave addr xfer done */
78
79 /* ICDMAER */
80 #define RSDMAE (1 << 3) /* DMA Slave Received Enable */
81 #define TSDMAE (1 << 2) /* DMA Slave Transmitted Enable */
82 #define RMDMAE (1 << 1) /* DMA Master Received Enable */
83 #define TMDMAE (1 << 0) /* DMA Master Transmitted Enable */
84
85 /* ICFBSCR */
86 #define TCYC06 0x04 /* 6*Tcyc delay 1st bit between SDA and SCL */
87 #define TCYC17 0x0f /* 17*Tcyc delay 1st bit between SDA and SCL */
88
89
90 #define RCAR_BUS_PHASE_START (MDBS | MIE | ESG)
91 #define RCAR_BUS_PHASE_DATA (MDBS | MIE)
92 #define RCAR_BUS_MASK_DATA (~(ESG | FSB) & 0xFF)
93 #define RCAR_BUS_PHASE_STOP (MDBS | MIE | FSB)
94
95 #define RCAR_IRQ_SEND (MNR | MAL | MST | MAT | MDE)
96 #define RCAR_IRQ_RECV (MNR | MAL | MST | MAT | MDR)
97 #define RCAR_IRQ_STOP (MST)
98
99 #define RCAR_IRQ_ACK_SEND (~(MAT | MDE) & 0x7F)
100 #define RCAR_IRQ_ACK_RECV (~(MAT | MDR) & 0x7F)
101
102 #define ID_LAST_MSG (1 << 0)
103 #define ID_FIRST_MSG (1 << 1)
104 #define ID_DONE (1 << 2)
105 #define ID_ARBLOST (1 << 3)
106 #define ID_NACK (1 << 4)
107 /* persistent flags */
108 #define ID_P_REP_AFTER_RD BIT(29)
109 #define ID_P_NO_RXDMA BIT(30) /* HW forbids RXDMA sometimes */
110 #define ID_P_PM_BLOCKED BIT(31)
111 #define ID_P_MASK GENMASK(31, 29)
112
113 enum rcar_i2c_type {
114 I2C_RCAR_GEN1,
115 I2C_RCAR_GEN2,
116 I2C_RCAR_GEN3,
117 };
118
119 struct rcar_i2c_priv {
120 void __iomem *io;
121 struct i2c_adapter adap;
122 struct i2c_msg *msg;
123 int msgs_left;
124 struct clk *clk;
125
126 wait_queue_head_t wait;
127
128 int pos;
129 u32 icccr;
130 u32 flags;
131 u8 recovery_icmcr; /* protected by adapter lock */
132 enum rcar_i2c_type devtype;
133 struct i2c_client *slave;
134
135 struct resource *res;
136 struct dma_chan *dma_tx;
137 struct dma_chan *dma_rx;
138 struct scatterlist sg;
139 enum dma_data_direction dma_direction;
140
141 struct reset_control *rstc;
142 };
143
144 #define rcar_i2c_priv_to_dev(p) ((p)->adap.dev.parent)
145 #define rcar_i2c_is_recv(p) ((p)->msg->flags & I2C_M_RD)
146
147 #define LOOP_TIMEOUT 1024
148
149
rcar_i2c_write(struct rcar_i2c_priv * priv,int reg,u32 val)150 static void rcar_i2c_write(struct rcar_i2c_priv *priv, int reg, u32 val)
151 {
152 writel(val, priv->io + reg);
153 }
154
rcar_i2c_read(struct rcar_i2c_priv * priv,int reg)155 static u32 rcar_i2c_read(struct rcar_i2c_priv *priv, int reg)
156 {
157 return readl(priv->io + reg);
158 }
159
rcar_i2c_get_scl(struct i2c_adapter * adap)160 static int rcar_i2c_get_scl(struct i2c_adapter *adap)
161 {
162 struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
163
164 return !!(rcar_i2c_read(priv, ICMCR) & FSCL);
165
166 };
167
rcar_i2c_set_scl(struct i2c_adapter * adap,int val)168 static void rcar_i2c_set_scl(struct i2c_adapter *adap, int val)
169 {
170 struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
171
172 if (val)
173 priv->recovery_icmcr |= FSCL;
174 else
175 priv->recovery_icmcr &= ~FSCL;
176
177 rcar_i2c_write(priv, ICMCR, priv->recovery_icmcr);
178 };
179
rcar_i2c_set_sda(struct i2c_adapter * adap,int val)180 static void rcar_i2c_set_sda(struct i2c_adapter *adap, int val)
181 {
182 struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
183
184 if (val)
185 priv->recovery_icmcr |= FSDA;
186 else
187 priv->recovery_icmcr &= ~FSDA;
188
189 rcar_i2c_write(priv, ICMCR, priv->recovery_icmcr);
190 };
191
rcar_i2c_get_bus_free(struct i2c_adapter * adap)192 static int rcar_i2c_get_bus_free(struct i2c_adapter *adap)
193 {
194 struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
195
196 return !(rcar_i2c_read(priv, ICMCR) & FSDA);
197
198 };
199
200 static struct i2c_bus_recovery_info rcar_i2c_bri = {
201 .get_scl = rcar_i2c_get_scl,
202 .set_scl = rcar_i2c_set_scl,
203 .set_sda = rcar_i2c_set_sda,
204 .get_bus_free = rcar_i2c_get_bus_free,
205 .recover_bus = i2c_generic_scl_recovery,
206 };
rcar_i2c_init(struct rcar_i2c_priv * priv)207 static void rcar_i2c_init(struct rcar_i2c_priv *priv)
208 {
209 /* reset master mode */
210 rcar_i2c_write(priv, ICMIER, 0);
211 rcar_i2c_write(priv, ICMCR, MDBS);
212 rcar_i2c_write(priv, ICMSR, 0);
213 /* start clock */
214 rcar_i2c_write(priv, ICCCR, priv->icccr);
215 }
216
rcar_i2c_bus_barrier(struct rcar_i2c_priv * priv)217 static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv)
218 {
219 int i;
220
221 for (i = 0; i < LOOP_TIMEOUT; i++) {
222 /* make sure that bus is not busy */
223 if (!(rcar_i2c_read(priv, ICMCR) & FSDA))
224 return 0;
225 udelay(1);
226 }
227
228 /* Waiting did not help, try to recover */
229 priv->recovery_icmcr = MDBS | OBPC | FSDA | FSCL;
230 return i2c_recover_bus(&priv->adap);
231 }
232
rcar_i2c_clock_calculate(struct rcar_i2c_priv * priv,struct i2c_timings * t)233 static int rcar_i2c_clock_calculate(struct rcar_i2c_priv *priv, struct i2c_timings *t)
234 {
235 u32 scgd, cdf, round, ick, sum, scl, cdf_width;
236 unsigned long rate;
237 struct device *dev = rcar_i2c_priv_to_dev(priv);
238
239 /* Fall back to previously used values if not supplied */
240 t->bus_freq_hz = t->bus_freq_hz ?: 100000;
241 t->scl_fall_ns = t->scl_fall_ns ?: 35;
242 t->scl_rise_ns = t->scl_rise_ns ?: 200;
243 t->scl_int_delay_ns = t->scl_int_delay_ns ?: 50;
244
245 switch (priv->devtype) {
246 case I2C_RCAR_GEN1:
247 cdf_width = 2;
248 break;
249 case I2C_RCAR_GEN2:
250 case I2C_RCAR_GEN3:
251 cdf_width = 3;
252 break;
253 default:
254 dev_err(dev, "device type error\n");
255 return -EIO;
256 }
257
258 /*
259 * calculate SCL clock
260 * see
261 * ICCCR
262 *
263 * ick = clkp / (1 + CDF)
264 * SCL = ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
265 *
266 * ick : I2C internal clock < 20 MHz
267 * ticf : I2C SCL falling time
268 * tr : I2C SCL rising time
269 * intd : LSI internal delay
270 * clkp : peripheral_clk
271 * F[] : integer up-valuation
272 */
273 rate = clk_get_rate(priv->clk);
274 cdf = rate / 20000000;
275 if (cdf >= 1U << cdf_width) {
276 dev_err(dev, "Input clock %lu too high\n", rate);
277 return -EIO;
278 }
279 ick = rate / (cdf + 1);
280
281 /*
282 * it is impossible to calculate large scale
283 * number on u32. separate it
284 *
285 * F[(ticf + tr + intd) * ick] with sum = (ticf + tr + intd)
286 * = F[sum * ick / 1000000000]
287 * = F[(ick / 1000000) * sum / 1000]
288 */
289 sum = t->scl_fall_ns + t->scl_rise_ns + t->scl_int_delay_ns;
290 round = (ick + 500000) / 1000000 * sum;
291 round = (round + 500) / 1000;
292
293 /*
294 * SCL = ick / (20 + SCGD * 8 + F[(ticf + tr + intd) * ick])
295 *
296 * Calculation result (= SCL) should be less than
297 * bus_speed for hardware safety
298 *
299 * We could use something along the lines of
300 * div = ick / (bus_speed + 1) + 1;
301 * scgd = (div - 20 - round + 7) / 8;
302 * scl = ick / (20 + (scgd * 8) + round);
303 * (not fully verified) but that would get pretty involved
304 */
305 for (scgd = 0; scgd < 0x40; scgd++) {
306 scl = ick / (20 + (scgd * 8) + round);
307 if (scl <= t->bus_freq_hz)
308 goto scgd_find;
309 }
310 dev_err(dev, "it is impossible to calculate best SCL\n");
311 return -EIO;
312
313 scgd_find:
314 dev_dbg(dev, "clk %d/%d(%lu), round %u, CDF:0x%x, SCGD: 0x%x\n",
315 scl, t->bus_freq_hz, clk_get_rate(priv->clk), round, cdf, scgd);
316
317 /* keep icccr value */
318 priv->icccr = scgd << cdf_width | cdf;
319
320 return 0;
321 }
322
rcar_i2c_prepare_msg(struct rcar_i2c_priv * priv)323 static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv)
324 {
325 int read = !!rcar_i2c_is_recv(priv);
326
327 priv->pos = 0;
328 if (priv->msgs_left == 1)
329 priv->flags |= ID_LAST_MSG;
330
331 rcar_i2c_write(priv, ICMAR, i2c_8bit_addr_from_msg(priv->msg));
332 /*
333 * We don't have a test case but the HW engineers say that the write order
334 * of ICMSR and ICMCR depends on whether we issue START or REP_START. Since
335 * it didn't cause a drawback for me, let's rather be safe than sorry.
336 */
337 if (priv->flags & ID_FIRST_MSG) {
338 rcar_i2c_write(priv, ICMSR, 0);
339 rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
340 } else {
341 if (priv->flags & ID_P_REP_AFTER_RD)
342 priv->flags &= ~ID_P_REP_AFTER_RD;
343 else
344 rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
345 rcar_i2c_write(priv, ICMSR, 0);
346 }
347 rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND);
348 }
349
rcar_i2c_next_msg(struct rcar_i2c_priv * priv)350 static void rcar_i2c_next_msg(struct rcar_i2c_priv *priv)
351 {
352 priv->msg++;
353 priv->msgs_left--;
354 priv->flags &= ID_P_MASK;
355 rcar_i2c_prepare_msg(priv);
356 }
357
358 /*
359 * interrupt functions
360 */
rcar_i2c_dma_unmap(struct rcar_i2c_priv * priv)361 static void rcar_i2c_dma_unmap(struct rcar_i2c_priv *priv)
362 {
363 struct dma_chan *chan = priv->dma_direction == DMA_FROM_DEVICE
364 ? priv->dma_rx : priv->dma_tx;
365
366 /* Disable DMA Master Received/Transmitted */
367 rcar_i2c_write(priv, ICDMAER, 0);
368
369 /* Reset default delay */
370 rcar_i2c_write(priv, ICFBSCR, TCYC06);
371
372 dma_unmap_single(chan->device->dev, sg_dma_address(&priv->sg),
373 sg_dma_len(&priv->sg), priv->dma_direction);
374
375 /* Gen3 can only do one RXDMA per transfer and we just completed it */
376 if (priv->devtype == I2C_RCAR_GEN3 &&
377 priv->dma_direction == DMA_FROM_DEVICE)
378 priv->flags |= ID_P_NO_RXDMA;
379
380 priv->dma_direction = DMA_NONE;
381 }
382
rcar_i2c_cleanup_dma(struct rcar_i2c_priv * priv)383 static void rcar_i2c_cleanup_dma(struct rcar_i2c_priv *priv)
384 {
385 if (priv->dma_direction == DMA_NONE)
386 return;
387 else if (priv->dma_direction == DMA_FROM_DEVICE)
388 dmaengine_terminate_all(priv->dma_rx);
389 else if (priv->dma_direction == DMA_TO_DEVICE)
390 dmaengine_terminate_all(priv->dma_tx);
391
392 rcar_i2c_dma_unmap(priv);
393 }
394
rcar_i2c_dma_callback(void * data)395 static void rcar_i2c_dma_callback(void *data)
396 {
397 struct rcar_i2c_priv *priv = data;
398
399 priv->pos += sg_dma_len(&priv->sg);
400
401 rcar_i2c_dma_unmap(priv);
402 }
403
rcar_i2c_dma(struct rcar_i2c_priv * priv)404 static void rcar_i2c_dma(struct rcar_i2c_priv *priv)
405 {
406 struct device *dev = rcar_i2c_priv_to_dev(priv);
407 struct i2c_msg *msg = priv->msg;
408 bool read = msg->flags & I2C_M_RD;
409 enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
410 struct dma_chan *chan = read ? priv->dma_rx : priv->dma_tx;
411 struct dma_async_tx_descriptor *txdesc;
412 dma_addr_t dma_addr;
413 dma_cookie_t cookie;
414 unsigned char *buf;
415 int len;
416
417 /* Do various checks to see if DMA is feasible at all */
418 if (IS_ERR(chan) || msg->len < 8 || !(msg->flags & I2C_M_DMA_SAFE) ||
419 (read && priv->flags & ID_P_NO_RXDMA))
420 return;
421
422 if (read) {
423 /*
424 * The last two bytes needs to be fetched using PIO in
425 * order for the STOP phase to work.
426 */
427 buf = priv->msg->buf;
428 len = priv->msg->len - 2;
429 } else {
430 /*
431 * First byte in message was sent using PIO.
432 */
433 buf = priv->msg->buf + 1;
434 len = priv->msg->len - 1;
435 }
436
437 dma_addr = dma_map_single(chan->device->dev, buf, len, dir);
438 if (dma_mapping_error(chan->device->dev, dma_addr)) {
439 dev_dbg(dev, "dma map failed, using PIO\n");
440 return;
441 }
442
443 sg_dma_len(&priv->sg) = len;
444 sg_dma_address(&priv->sg) = dma_addr;
445
446 priv->dma_direction = dir;
447
448 txdesc = dmaengine_prep_slave_sg(chan, &priv->sg, 1,
449 read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
450 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
451 if (!txdesc) {
452 dev_dbg(dev, "dma prep slave sg failed, using PIO\n");
453 rcar_i2c_cleanup_dma(priv);
454 return;
455 }
456
457 txdesc->callback = rcar_i2c_dma_callback;
458 txdesc->callback_param = priv;
459
460 cookie = dmaengine_submit(txdesc);
461 if (dma_submit_error(cookie)) {
462 dev_dbg(dev, "submitting dma failed, using PIO\n");
463 rcar_i2c_cleanup_dma(priv);
464 return;
465 }
466
467 /* Set delay for DMA operations */
468 rcar_i2c_write(priv, ICFBSCR, TCYC17);
469
470 /* Enable DMA Master Received/Transmitted */
471 if (read)
472 rcar_i2c_write(priv, ICDMAER, RMDMAE);
473 else
474 rcar_i2c_write(priv, ICDMAER, TMDMAE);
475
476 dma_async_issue_pending(chan);
477 }
478
rcar_i2c_irq_send(struct rcar_i2c_priv * priv,u32 msr)479 static void rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr)
480 {
481 struct i2c_msg *msg = priv->msg;
482
483 /* FIXME: sometimes, unknown interrupt happened. Do nothing */
484 if (!(msr & MDE))
485 return;
486
487 if (priv->pos < msg->len) {
488 /*
489 * Prepare next data to ICRXTX register.
490 * This data will go to _SHIFT_ register.
491 *
492 * *
493 * [ICRXTX] -> [SHIFT] -> [I2C bus]
494 */
495 rcar_i2c_write(priv, ICRXTX, msg->buf[priv->pos]);
496 priv->pos++;
497
498 /*
499 * Try to use DMA to transmit the rest of the data if
500 * address transfer phase just finished.
501 */
502 if (msr & MAT)
503 rcar_i2c_dma(priv);
504 } else {
505 /*
506 * The last data was pushed to ICRXTX on _PREV_ empty irq.
507 * It is on _SHIFT_ register, and will sent to I2C bus.
508 *
509 * *
510 * [ICRXTX] -> [SHIFT] -> [I2C bus]
511 */
512
513 if (priv->flags & ID_LAST_MSG) {
514 /*
515 * If current msg is the _LAST_ msg,
516 * prepare stop condition here.
517 * ID_DONE will be set on STOP irq.
518 */
519 rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
520 } else {
521 rcar_i2c_next_msg(priv);
522 return;
523 }
524 }
525
526 rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_SEND);
527 }
528
rcar_i2c_irq_recv(struct rcar_i2c_priv * priv,u32 msr)529 static void rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr)
530 {
531 struct i2c_msg *msg = priv->msg;
532
533 /* FIXME: sometimes, unknown interrupt happened. Do nothing */
534 if (!(msr & MDR))
535 return;
536
537 if (msr & MAT) {
538 /*
539 * Address transfer phase finished, but no data at this point.
540 * Try to use DMA to receive data.
541 */
542 rcar_i2c_dma(priv);
543 } else if (priv->pos < msg->len) {
544 /* get received data */
545 msg->buf[priv->pos] = rcar_i2c_read(priv, ICRXTX);
546 priv->pos++;
547 }
548
549 /* If next received data is the _LAST_, go to new phase. */
550 if (priv->pos + 1 == msg->len) {
551 if (priv->flags & ID_LAST_MSG) {
552 rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP);
553 } else {
554 rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_START);
555 priv->flags |= ID_P_REP_AFTER_RD;
556 }
557 }
558
559 if (priv->pos == msg->len && !(priv->flags & ID_LAST_MSG))
560 rcar_i2c_next_msg(priv);
561 else
562 rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_RECV);
563 }
564
rcar_i2c_slave_irq(struct rcar_i2c_priv * priv)565 static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
566 {
567 u32 ssr_raw, ssr_filtered;
568 u8 value;
569
570 ssr_raw = rcar_i2c_read(priv, ICSSR) & 0xff;
571 ssr_filtered = ssr_raw & rcar_i2c_read(priv, ICSIER);
572
573 if (!ssr_filtered)
574 return false;
575
576 /* address detected */
577 if (ssr_filtered & SAR) {
578 /* read or write request */
579 if (ssr_raw & STM) {
580 i2c_slave_event(priv->slave, I2C_SLAVE_READ_REQUESTED, &value);
581 rcar_i2c_write(priv, ICRXTX, value);
582 rcar_i2c_write(priv, ICSIER, SDE | SSR | SAR);
583 } else {
584 i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
585 rcar_i2c_read(priv, ICRXTX); /* dummy read */
586 rcar_i2c_write(priv, ICSIER, SDR | SSR | SAR);
587 }
588
589 rcar_i2c_write(priv, ICSSR, ~SAR & 0xff);
590 }
591
592 /* master sent stop */
593 if (ssr_filtered & SSR) {
594 i2c_slave_event(priv->slave, I2C_SLAVE_STOP, &value);
595 rcar_i2c_write(priv, ICSIER, SAR | SSR);
596 rcar_i2c_write(priv, ICSSR, ~SSR & 0xff);
597 }
598
599 /* master wants to write to us */
600 if (ssr_filtered & SDR) {
601 int ret;
602
603 value = rcar_i2c_read(priv, ICRXTX);
604 ret = i2c_slave_event(priv->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
605 /* Send NACK in case of error */
606 rcar_i2c_write(priv, ICSCR, SIE | SDBS | (ret < 0 ? FNA : 0));
607 rcar_i2c_write(priv, ICSSR, ~SDR & 0xff);
608 }
609
610 /* master wants to read from us */
611 if (ssr_filtered & SDE) {
612 i2c_slave_event(priv->slave, I2C_SLAVE_READ_PROCESSED, &value);
613 rcar_i2c_write(priv, ICRXTX, value);
614 rcar_i2c_write(priv, ICSSR, ~SDE & 0xff);
615 }
616
617 return true;
618 }
619
rcar_i2c_irq(int irq,void * ptr)620 static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
621 {
622 struct rcar_i2c_priv *priv = ptr;
623 u32 msr, val;
624
625 /* Clear START or STOP immediately, except for REPSTART after read */
626 if (likely(!(priv->flags & ID_P_REP_AFTER_RD))) {
627 val = rcar_i2c_read(priv, ICMCR);
628 rcar_i2c_write(priv, ICMCR, val & RCAR_BUS_MASK_DATA);
629 }
630
631 msr = rcar_i2c_read(priv, ICMSR);
632
633 /* Only handle interrupts that are currently enabled */
634 msr &= rcar_i2c_read(priv, ICMIER);
635 if (!msr) {
636 if (rcar_i2c_slave_irq(priv))
637 return IRQ_HANDLED;
638
639 return IRQ_NONE;
640 }
641
642 /* Arbitration lost */
643 if (msr & MAL) {
644 priv->flags |= ID_DONE | ID_ARBLOST;
645 goto out;
646 }
647
648 /* Nack */
649 if (msr & MNR) {
650 /* HW automatically sends STOP after received NACK */
651 rcar_i2c_write(priv, ICMIER, RCAR_IRQ_STOP);
652 priv->flags |= ID_NACK;
653 goto out;
654 }
655
656 /* Stop */
657 if (msr & MST) {
658 priv->msgs_left--; /* The last message also made it */
659 priv->flags |= ID_DONE;
660 goto out;
661 }
662
663 if (rcar_i2c_is_recv(priv))
664 rcar_i2c_irq_recv(priv, msr);
665 else
666 rcar_i2c_irq_send(priv, msr);
667
668 out:
669 if (priv->flags & ID_DONE) {
670 rcar_i2c_write(priv, ICMIER, 0);
671 rcar_i2c_write(priv, ICMSR, 0);
672 wake_up(&priv->wait);
673 }
674
675 return IRQ_HANDLED;
676 }
677
rcar_i2c_request_dma_chan(struct device * dev,enum dma_transfer_direction dir,dma_addr_t port_addr)678 static struct dma_chan *rcar_i2c_request_dma_chan(struct device *dev,
679 enum dma_transfer_direction dir,
680 dma_addr_t port_addr)
681 {
682 struct dma_chan *chan;
683 struct dma_slave_config cfg;
684 char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
685 int ret;
686
687 chan = dma_request_chan(dev, chan_name);
688 if (IS_ERR(chan)) {
689 dev_dbg(dev, "request_channel failed for %s (%ld)\n",
690 chan_name, PTR_ERR(chan));
691 return chan;
692 }
693
694 memset(&cfg, 0, sizeof(cfg));
695 cfg.direction = dir;
696 if (dir == DMA_MEM_TO_DEV) {
697 cfg.dst_addr = port_addr;
698 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
699 } else {
700 cfg.src_addr = port_addr;
701 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
702 }
703
704 ret = dmaengine_slave_config(chan, &cfg);
705 if (ret) {
706 dev_dbg(dev, "slave_config failed for %s (%d)\n",
707 chan_name, ret);
708 dma_release_channel(chan);
709 return ERR_PTR(ret);
710 }
711
712 dev_dbg(dev, "got DMA channel for %s\n", chan_name);
713 return chan;
714 }
715
rcar_i2c_request_dma(struct rcar_i2c_priv * priv,struct i2c_msg * msg)716 static void rcar_i2c_request_dma(struct rcar_i2c_priv *priv,
717 struct i2c_msg *msg)
718 {
719 struct device *dev = rcar_i2c_priv_to_dev(priv);
720 bool read;
721 struct dma_chan *chan;
722 enum dma_transfer_direction dir;
723
724 read = msg->flags & I2C_M_RD;
725
726 chan = read ? priv->dma_rx : priv->dma_tx;
727 if (PTR_ERR(chan) != -EPROBE_DEFER)
728 return;
729
730 dir = read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV;
731 chan = rcar_i2c_request_dma_chan(dev, dir, priv->res->start + ICRXTX);
732
733 if (read)
734 priv->dma_rx = chan;
735 else
736 priv->dma_tx = chan;
737 }
738
rcar_i2c_release_dma(struct rcar_i2c_priv * priv)739 static void rcar_i2c_release_dma(struct rcar_i2c_priv *priv)
740 {
741 if (!IS_ERR(priv->dma_tx)) {
742 dma_release_channel(priv->dma_tx);
743 priv->dma_tx = ERR_PTR(-EPROBE_DEFER);
744 }
745
746 if (!IS_ERR(priv->dma_rx)) {
747 dma_release_channel(priv->dma_rx);
748 priv->dma_rx = ERR_PTR(-EPROBE_DEFER);
749 }
750 }
751
752 /* I2C is a special case, we need to poll the status of a reset */
rcar_i2c_do_reset(struct rcar_i2c_priv * priv)753 static int rcar_i2c_do_reset(struct rcar_i2c_priv *priv)
754 {
755 int i, ret;
756
757 ret = reset_control_reset(priv->rstc);
758 if (ret)
759 return ret;
760
761 for (i = 0; i < LOOP_TIMEOUT; i++) {
762 ret = reset_control_status(priv->rstc);
763 if (ret == 0)
764 return 0;
765 udelay(1);
766 }
767
768 return -ETIMEDOUT;
769 }
770
rcar_i2c_master_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)771 static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
772 struct i2c_msg *msgs,
773 int num)
774 {
775 struct rcar_i2c_priv *priv = i2c_get_adapdata(adap);
776 struct device *dev = rcar_i2c_priv_to_dev(priv);
777 int i, ret;
778 long time_left;
779
780 pm_runtime_get_sync(dev);
781
782 /* Gen3 needs a reset before allowing RXDMA once */
783 if (priv->devtype == I2C_RCAR_GEN3) {
784 priv->flags |= ID_P_NO_RXDMA;
785 if (!IS_ERR(priv->rstc)) {
786 ret = rcar_i2c_do_reset(priv);
787 if (ret == 0)
788 priv->flags &= ~ID_P_NO_RXDMA;
789 }
790 }
791
792 rcar_i2c_init(priv);
793
794 ret = rcar_i2c_bus_barrier(priv);
795 if (ret < 0)
796 goto out;
797
798 for (i = 0; i < num; i++)
799 rcar_i2c_request_dma(priv, msgs + i);
800
801 /* init first message */
802 priv->msg = msgs;
803 priv->msgs_left = num;
804 priv->flags = (priv->flags & ID_P_MASK) | ID_FIRST_MSG;
805 rcar_i2c_prepare_msg(priv);
806
807 time_left = wait_event_timeout(priv->wait, priv->flags & ID_DONE,
808 num * adap->timeout);
809
810 /* cleanup DMA if it couldn't complete properly due to an error */
811 if (priv->dma_direction != DMA_NONE)
812 rcar_i2c_cleanup_dma(priv);
813
814 if (!time_left) {
815 rcar_i2c_init(priv);
816 ret = -ETIMEDOUT;
817 } else if (priv->flags & ID_NACK) {
818 ret = -ENXIO;
819 } else if (priv->flags & ID_ARBLOST) {
820 ret = -EAGAIN;
821 } else {
822 ret = num - priv->msgs_left; /* The number of transfer */
823 }
824 out:
825 pm_runtime_put(dev);
826
827 if (ret < 0 && ret != -ENXIO)
828 dev_err(dev, "error %d : %x\n", ret, priv->flags);
829
830 return ret;
831 }
832
rcar_reg_slave(struct i2c_client * slave)833 static int rcar_reg_slave(struct i2c_client *slave)
834 {
835 struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
836
837 if (priv->slave)
838 return -EBUSY;
839
840 if (slave->flags & I2C_CLIENT_TEN)
841 return -EAFNOSUPPORT;
842
843 /* Keep device active for slave address detection logic */
844 pm_runtime_get_sync(rcar_i2c_priv_to_dev(priv));
845
846 priv->slave = slave;
847 rcar_i2c_write(priv, ICSAR, slave->addr);
848 rcar_i2c_write(priv, ICSSR, 0);
849 rcar_i2c_write(priv, ICSIER, SAR | SSR);
850 rcar_i2c_write(priv, ICSCR, SIE | SDBS);
851
852 return 0;
853 }
854
rcar_unreg_slave(struct i2c_client * slave)855 static int rcar_unreg_slave(struct i2c_client *slave)
856 {
857 struct rcar_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
858
859 WARN_ON(!priv->slave);
860
861 rcar_i2c_write(priv, ICSIER, 0);
862 rcar_i2c_write(priv, ICSCR, 0);
863
864 priv->slave = NULL;
865
866 pm_runtime_put(rcar_i2c_priv_to_dev(priv));
867
868 return 0;
869 }
870
rcar_i2c_func(struct i2c_adapter * adap)871 static u32 rcar_i2c_func(struct i2c_adapter *adap)
872 {
873 /*
874 * This HW can't do:
875 * I2C_SMBUS_QUICK (setting FSB during START didn't work)
876 * I2C_M_NOSTART (automatically sends address after START)
877 * I2C_M_IGNORE_NAK (automatically sends STOP after NAK)
878 */
879 return I2C_FUNC_I2C | I2C_FUNC_SLAVE |
880 (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
881 }
882
883 static const struct i2c_algorithm rcar_i2c_algo = {
884 .master_xfer = rcar_i2c_master_xfer,
885 .functionality = rcar_i2c_func,
886 .reg_slave = rcar_reg_slave,
887 .unreg_slave = rcar_unreg_slave,
888 };
889
890 static const struct i2c_adapter_quirks rcar_i2c_quirks = {
891 .flags = I2C_AQ_NO_ZERO_LEN,
892 };
893
894 static const struct of_device_id rcar_i2c_dt_ids[] = {
895 { .compatible = "renesas,i2c-r8a7778", .data = (void *)I2C_RCAR_GEN1 },
896 { .compatible = "renesas,i2c-r8a7779", .data = (void *)I2C_RCAR_GEN1 },
897 { .compatible = "renesas,i2c-r8a7790", .data = (void *)I2C_RCAR_GEN2 },
898 { .compatible = "renesas,i2c-r8a7791", .data = (void *)I2C_RCAR_GEN2 },
899 { .compatible = "renesas,i2c-r8a7792", .data = (void *)I2C_RCAR_GEN2 },
900 { .compatible = "renesas,i2c-r8a7793", .data = (void *)I2C_RCAR_GEN2 },
901 { .compatible = "renesas,i2c-r8a7794", .data = (void *)I2C_RCAR_GEN2 },
902 { .compatible = "renesas,i2c-r8a7795", .data = (void *)I2C_RCAR_GEN3 },
903 { .compatible = "renesas,i2c-r8a7796", .data = (void *)I2C_RCAR_GEN3 },
904 { .compatible = "renesas,i2c-rcar", .data = (void *)I2C_RCAR_GEN1 }, /* Deprecated */
905 { .compatible = "renesas,rcar-gen1-i2c", .data = (void *)I2C_RCAR_GEN1 },
906 { .compatible = "renesas,rcar-gen2-i2c", .data = (void *)I2C_RCAR_GEN2 },
907 { .compatible = "renesas,rcar-gen3-i2c", .data = (void *)I2C_RCAR_GEN3 },
908 {},
909 };
910 MODULE_DEVICE_TABLE(of, rcar_i2c_dt_ids);
911
rcar_i2c_probe(struct platform_device * pdev)912 static int rcar_i2c_probe(struct platform_device *pdev)
913 {
914 struct rcar_i2c_priv *priv;
915 struct i2c_adapter *adap;
916 struct device *dev = &pdev->dev;
917 struct i2c_timings i2c_t;
918 int irq, ret;
919
920 priv = devm_kzalloc(dev, sizeof(struct rcar_i2c_priv), GFP_KERNEL);
921 if (!priv)
922 return -ENOMEM;
923
924 priv->clk = devm_clk_get(dev, NULL);
925 if (IS_ERR(priv->clk)) {
926 dev_err(dev, "cannot get clock\n");
927 return PTR_ERR(priv->clk);
928 }
929
930 priv->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
931
932 priv->io = devm_ioremap_resource(dev, priv->res);
933 if (IS_ERR(priv->io))
934 return PTR_ERR(priv->io);
935
936 priv->devtype = (enum rcar_i2c_type)of_device_get_match_data(dev);
937 init_waitqueue_head(&priv->wait);
938
939 adap = &priv->adap;
940 adap->nr = pdev->id;
941 adap->algo = &rcar_i2c_algo;
942 adap->class = I2C_CLASS_DEPRECATED;
943 adap->retries = 3;
944 adap->dev.parent = dev;
945 adap->dev.of_node = dev->of_node;
946 adap->bus_recovery_info = &rcar_i2c_bri;
947 adap->quirks = &rcar_i2c_quirks;
948 i2c_set_adapdata(adap, priv);
949 strlcpy(adap->name, pdev->name, sizeof(adap->name));
950
951 i2c_parse_fw_timings(dev, &i2c_t, false);
952
953 /* Init DMA */
954 sg_init_table(&priv->sg, 1);
955 priv->dma_direction = DMA_NONE;
956 priv->dma_rx = priv->dma_tx = ERR_PTR(-EPROBE_DEFER);
957
958 /* Activate device for clock calculation */
959 pm_runtime_enable(dev);
960 pm_runtime_get_sync(dev);
961 ret = rcar_i2c_clock_calculate(priv, &i2c_t);
962 if (ret < 0)
963 goto out_pm_put;
964
965 if (priv->devtype == I2C_RCAR_GEN3) {
966 priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
967 if (!IS_ERR(priv->rstc)) {
968 ret = reset_control_status(priv->rstc);
969 if (ret < 0)
970 priv->rstc = ERR_PTR(-ENOTSUPP);
971 }
972 }
973
974 /* Stay always active when multi-master to keep arbitration working */
975 if (of_property_read_bool(dev->of_node, "multi-master"))
976 priv->flags |= ID_P_PM_BLOCKED;
977 else
978 pm_runtime_put(dev);
979
980
981 irq = platform_get_irq(pdev, 0);
982 ret = devm_request_irq(dev, irq, rcar_i2c_irq, 0, dev_name(dev), priv);
983 if (ret < 0) {
984 dev_err(dev, "cannot get irq %d\n", irq);
985 goto out_pm_disable;
986 }
987
988 platform_set_drvdata(pdev, priv);
989
990 ret = i2c_add_numbered_adapter(adap);
991 if (ret < 0)
992 goto out_pm_disable;
993
994 dev_info(dev, "probed\n");
995
996 return 0;
997
998 out_pm_put:
999 pm_runtime_put(dev);
1000 out_pm_disable:
1001 pm_runtime_disable(dev);
1002 return ret;
1003 }
1004
rcar_i2c_remove(struct platform_device * pdev)1005 static int rcar_i2c_remove(struct platform_device *pdev)
1006 {
1007 struct rcar_i2c_priv *priv = platform_get_drvdata(pdev);
1008 struct device *dev = &pdev->dev;
1009
1010 i2c_del_adapter(&priv->adap);
1011 rcar_i2c_release_dma(priv);
1012 if (priv->flags & ID_P_PM_BLOCKED)
1013 pm_runtime_put(dev);
1014 pm_runtime_disable(dev);
1015
1016 return 0;
1017 }
1018
1019 static struct platform_driver rcar_i2c_driver = {
1020 .driver = {
1021 .name = "i2c-rcar",
1022 .of_match_table = rcar_i2c_dt_ids,
1023 },
1024 .probe = rcar_i2c_probe,
1025 .remove = rcar_i2c_remove,
1026 };
1027
1028 module_platform_driver(rcar_i2c_driver);
1029
1030 MODULE_LICENSE("GPL v2");
1031 MODULE_DESCRIPTION("Renesas R-Car I2C bus driver");
1032 MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
1033
