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hwrng: core - Don't use a stack buffer in add_early_randomness()
[linux/fpc-iii.git] / drivers / i2c / busses / i2c-sh_mobile.c
blob192f36f00e4d3d345e556e75da9ee6b826604104
1 /*
2 * SuperH Mobile I2C Controller
3 *
4 * Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com>
5 *
6 * Copyright (C) 2008 Magnus Damm
7 *
8 * Portions of the code based on out-of-tree driver i2c-sh7343.c
9 * Copyright (c) 2006 Carlos Munoz <carlos@kenati.com>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 */
20
21 #include <linux/clk.h>
22 #include <linux/delay.h>
23 #include <linux/dmaengine.h>
24 #include <linux/dma-mapping.h>
25 #include <linux/err.h>
26 #include <linux/i2c.h>
27 #include <linux/i2c/i2c-sh_mobile.h>
28 #include <linux/init.h>
29 #include <linux/interrupt.h>
30 #include <linux/io.h>
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/of_device.h>
34 #include <linux/platform_device.h>
35 #include <linux/pm_runtime.h>
36 #include <linux/slab.h>
37
38 /* Transmit operation: */
39 /* */
40 /* 0 byte transmit */
41 /* BUS: S A8 ACK P(*) */
42 /* IRQ: DTE WAIT */
43 /* ICIC: */
44 /* ICCR: 0x94 0x90 */
45 /* ICDR: A8 */
46 /* */
47 /* 1 byte transmit */
48 /* BUS: S A8 ACK D8(1) ACK P(*) */
49 /* IRQ: DTE WAIT WAIT */
50 /* ICIC: -DTE */
51 /* ICCR: 0x94 0x90 */
52 /* ICDR: A8 D8(1) */
53 /* */
54 /* 2 byte transmit */
55 /* BUS: S A8 ACK D8(1) ACK D8(2) ACK P(*) */
56 /* IRQ: DTE WAIT WAIT WAIT */
57 /* ICIC: -DTE */
58 /* ICCR: 0x94 0x90 */
59 /* ICDR: A8 D8(1) D8(2) */
60 /* */
61 /* 3 bytes or more, +---------+ gets repeated */
62 /* */
63 /* */
64 /* Receive operation: */
65 /* */
66 /* 0 byte receive - not supported since slave may hold SDA low */
67 /* */
68 /* 1 byte receive [TX] | [RX] */
69 /* BUS: S A8 ACK | D8(1) ACK P(*) */
70 /* IRQ: DTE WAIT | WAIT DTE */
71 /* ICIC: -DTE | +DTE */
72 /* ICCR: 0x94 0x81 | 0xc0 */
73 /* ICDR: A8 | D8(1) */
74 /* */
75 /* 2 byte receive [TX]| [RX] */
76 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK P(*) */
77 /* IRQ: DTE WAIT | WAIT WAIT DTE */
78 /* ICIC: -DTE | +DTE */
79 /* ICCR: 0x94 0x81 | 0xc0 */
80 /* ICDR: A8 | D8(1) D8(2) */
81 /* */
82 /* 3 byte receive [TX] | [RX] (*) */
83 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK D8(3) ACK P */
84 /* IRQ: DTE WAIT | WAIT WAIT WAIT DTE */
85 /* ICIC: -DTE | +DTE */
86 /* ICCR: 0x94 0x81 | 0xc0 */
87 /* ICDR: A8 | D8(1) D8(2) D8(3) */
88 /* */
89 /* 4 bytes or more, this part is repeated +---------+ */
90 /* */
91 /* */
92 /* Interrupt order and BUSY flag */
93 /* ___ _ */
94 /* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */
95 /* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */
96 /* */
97 /* S D7 D6 D5 D4 D3 D2 D1 D0 P(*) */
98 /* ___ */
99 /* WAIT IRQ ________________________________/ \___________ */
100 /* TACK IRQ ____________________________________/ \_______ */
101 /* DTE IRQ __________________________________________/ \_ */
102 /* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
103 /* _______________________________________________ */
104 /* BUSY __/ \_ */
105 /* */
106 /* (*) The STOP condition is only sent by the master at the end of the last */
107 /* I2C message or if the I2C_M_STOP flag is set. Similarly, the BUSY bit is */
108 /* only cleared after the STOP condition, so, between messages we have to */
109 /* poll for the DTE bit. */
110 /* */
111
112 enum sh_mobile_i2c_op {
113 OP_START = 0,
114 OP_TX_FIRST,
115 OP_TX,
116 OP_TX_STOP,
117 OP_TX_STOP_DATA,
118 OP_TX_TO_RX,
119 OP_RX,
120 OP_RX_STOP,
121 OP_RX_STOP_DATA,
122 };
123
124 struct sh_mobile_i2c_data {
125 struct device *dev;
126 void __iomem *reg;
127 struct i2c_adapter adap;
128 unsigned long bus_speed;
129 unsigned int clks_per_count;
130 struct clk *clk;
131 u_int8_t icic;
132 u_int8_t flags;
133 u_int16_t iccl;
134 u_int16_t icch;
135
136 spinlock_t lock;
137 wait_queue_head_t wait;
138 struct i2c_msg *msg;
139 int pos;
140 int sr;
141 bool send_stop;
142 bool stop_after_dma;
143
144 struct resource *res;
145 struct dma_chan *dma_tx;
146 struct dma_chan *dma_rx;
147 struct scatterlist sg;
148 enum dma_data_direction dma_direction;
149 };
150
151 struct sh_mobile_dt_config {
152 int clks_per_count;
153 void (*setup)(struct sh_mobile_i2c_data *pd);
154 };
155
156 #define IIC_FLAG_HAS_ICIC67 (1 << 0)
157
158 #define STANDARD_MODE 100000
159 #define FAST_MODE 400000
160
161 /* Register offsets */
162 #define ICDR 0x00
163 #define ICCR 0x04
164 #define ICSR 0x08
165 #define ICIC 0x0c
166 #define ICCL 0x10
167 #define ICCH 0x14
168 #define ICSTART 0x70
169
170 /* Register bits */
171 #define ICCR_ICE 0x80
172 #define ICCR_RACK 0x40
173 #define ICCR_TRS 0x10
174 #define ICCR_BBSY 0x04
175 #define ICCR_SCP 0x01
176
177 #define ICSR_SCLM 0x80
178 #define ICSR_SDAM 0x40
179 #define SW_DONE 0x20
180 #define ICSR_BUSY 0x10
181 #define ICSR_AL 0x08
182 #define ICSR_TACK 0x04
183 #define ICSR_WAIT 0x02
184 #define ICSR_DTE 0x01
185
186 #define ICIC_ICCLB8 0x80
187 #define ICIC_ICCHB8 0x40
188 #define ICIC_TDMAE 0x20
189 #define ICIC_RDMAE 0x10
190 #define ICIC_ALE 0x08
191 #define ICIC_TACKE 0x04
192 #define ICIC_WAITE 0x02
193 #define ICIC_DTEE 0x01
194
195 #define ICSTART_ICSTART 0x10
196
197 static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data)
198 {
199 if (offs == ICIC)
200 data |= pd->icic;
201
202 iowrite8(data, pd->reg + offs);
203 }
204
205 static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs)
206 {
207 return ioread8(pd->reg + offs);
208 }
209
210 static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs,
211 unsigned char set, unsigned char clr)
212 {
213 iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr);
214 }
215
216 static u32 sh_mobile_i2c_iccl(unsigned long count_khz, u32 tLOW, u32 tf)
217 {
218 /*
219 * Conditional expression:
220 * ICCL >= COUNT_CLK * (tLOW + tf)
221 *
222 * SH-Mobile IIC hardware starts counting the LOW period of
223 * the SCL signal (tLOW) as soon as it pulls the SCL line.
224 * In order to meet the tLOW timing spec, we need to take into
225 * account the fall time of SCL signal (tf). Default tf value
226 * should be 0.3 us, for safety.
227 */
228 return (((count_khz * (tLOW + tf)) + 5000) / 10000);
229 }
230
231 static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf)
232 {
233 /*
234 * Conditional expression:
235 * ICCH >= COUNT_CLK * (tHIGH + tf)
236 *
237 * SH-Mobile IIC hardware is aware of SCL transition period 'tr',
238 * and can ignore it. SH-Mobile IIC controller starts counting
239 * the HIGH period of the SCL signal (tHIGH) after the SCL input
240 * voltage increases at VIH.
241 *
242 * Afterward it turned out calculating ICCH using only tHIGH spec
243 * will result in violation of the tHD;STA timing spec. We need
244 * to take into account the fall time of SDA signal (tf) at START
245 * condition, in order to meet both tHIGH and tHD;STA specs.
246 */
247 return (((count_khz * (tHIGH + tf)) + 5000) / 10000);
248 }
249
250 static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
251 {
252 unsigned long i2c_clk_khz;
253 u32 tHIGH, tLOW, tf;
254 uint16_t max_val;
255
256 /* Get clock rate after clock is enabled */
257 clk_prepare_enable(pd->clk);
258 i2c_clk_khz = clk_get_rate(pd->clk) / 1000;
259 clk_disable_unprepare(pd->clk);
260 i2c_clk_khz /= pd->clks_per_count;
261
262 if (pd->bus_speed == STANDARD_MODE) {
263 tLOW = 47; /* tLOW = 4.7 us */
264 tHIGH = 40; /* tHD;STA = tHIGH = 4.0 us */
265 tf = 3; /* tf = 0.3 us */
266 } else if (pd->bus_speed == FAST_MODE) {
267 tLOW = 13; /* tLOW = 1.3 us */
268 tHIGH = 6; /* tHD;STA = tHIGH = 0.6 us */
269 tf = 3; /* tf = 0.3 us */
270 } else {
271 dev_err(pd->dev, "unrecognized bus speed %lu Hz\n",
272 pd->bus_speed);
273 return -EINVAL;
274 }
275
276 pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf);
277 pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf);
278
279 max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff;
280 if (pd->iccl > max_val || pd->icch > max_val) {
281 dev_err(pd->dev, "timing values out of range: L/H=0x%x/0x%x\n",
282 pd->iccl, pd->icch);
283 return -EINVAL;
284 }
285
286 /* one more bit of ICCL in ICIC */
287 if (pd->iccl & 0x100)
288 pd->icic |= ICIC_ICCLB8;
289 else
290 pd->icic &= ~ICIC_ICCLB8;
291
292 /* one more bit of ICCH in ICIC */
293 if (pd->icch & 0x100)
294 pd->icic |= ICIC_ICCHB8;
295 else
296 pd->icic &= ~ICIC_ICCHB8;
297
298 dev_dbg(pd->dev, "timing values: L/H=0x%x/0x%x\n", pd->iccl, pd->icch);
299 return 0;
300 }
301
302 static void activate_ch(struct sh_mobile_i2c_data *pd)
303 {
304 /* Wake up device and enable clock */
305 pm_runtime_get_sync(pd->dev);
306 clk_prepare_enable(pd->clk);
307
308 /* Enable channel and configure rx ack */
309 iic_set_clr(pd, ICCR, ICCR_ICE, 0);
310
311 /* Mask all interrupts */
312 iic_wr(pd, ICIC, 0);
313
314 /* Set the clock */
315 iic_wr(pd, ICCL, pd->iccl & 0xff);
316 iic_wr(pd, ICCH, pd->icch & 0xff);
317 }
318
319 static void deactivate_ch(struct sh_mobile_i2c_data *pd)
320 {
321 /* Clear/disable interrupts */
322 iic_wr(pd, ICSR, 0);
323 iic_wr(pd, ICIC, 0);
324
325 /* Disable channel */
326 iic_set_clr(pd, ICCR, 0, ICCR_ICE);
327
328 /* Disable clock and mark device as idle */
329 clk_disable_unprepare(pd->clk);
330 pm_runtime_put_sync(pd->dev);
331 }
332
333 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
334 enum sh_mobile_i2c_op op, unsigned char data)
335 {
336 unsigned char ret = 0;
337 unsigned long flags;
338
339 dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
340
341 spin_lock_irqsave(&pd->lock, flags);
342
343 switch (op) {
344 case OP_START: /* issue start and trigger DTE interrupt */
345 iic_wr(pd, ICCR, ICCR_ICE | ICCR_TRS | ICCR_BBSY);
346 break;
347 case OP_TX_FIRST: /* disable DTE interrupt and write data */
348 iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
349 iic_wr(pd, ICDR, data);
350 break;
351 case OP_TX: /* write data */
352 iic_wr(pd, ICDR, data);
353 break;
354 case OP_TX_STOP_DATA: /* write data and issue a stop afterwards */
355 iic_wr(pd, ICDR, data);
356 /* fallthrough */
357 case OP_TX_STOP: /* issue a stop */
358 iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS
359 : ICCR_ICE | ICCR_TRS | ICCR_BBSY);
360 break;
361 case OP_TX_TO_RX: /* select read mode */
362 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP);
363 break;
364 case OP_RX: /* just read data */
365 ret = iic_rd(pd, ICDR);
366 break;
367 case OP_RX_STOP: /* enable DTE interrupt, issue stop */
368 iic_wr(pd, ICIC,
369 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
370 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
371 break;
372 case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
373 iic_wr(pd, ICIC,
374 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
375 ret = iic_rd(pd, ICDR);
376 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
377 break;
378 }
379
380 spin_unlock_irqrestore(&pd->lock, flags);
381
382 dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
383 return ret;
384 }
385
386 static bool sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
387 {
388 return pd->pos == -1;
389 }
390
391 static bool sh_mobile_i2c_is_last_byte(struct sh_mobile_i2c_data *pd)
392 {
393 return pd->pos == pd->msg->len - 1;
394 }
395
396 static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
397 unsigned char *buf)
398 {
399 switch (pd->pos) {
400 case -1:
401 *buf = i2c_8bit_addr_from_msg(pd->msg);
402 break;
403 default:
404 *buf = pd->msg->buf[pd->pos];
405 }
406 }
407
408 static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
409 {
410 unsigned char data;
411
412 if (pd->pos == pd->msg->len) {
413 /* Send stop if we haven't yet (DMA case) */
414 if (pd->send_stop && pd->stop_after_dma)
415 i2c_op(pd, OP_TX_STOP, 0);
416 return 1;
417 }
418
419 sh_mobile_i2c_get_data(pd, &data);
420
421 if (sh_mobile_i2c_is_last_byte(pd))
422 i2c_op(pd, OP_TX_STOP_DATA, data);
423 else if (sh_mobile_i2c_is_first_byte(pd))
424 i2c_op(pd, OP_TX_FIRST, data);
425 else
426 i2c_op(pd, OP_TX, data);
427
428 pd->pos++;
429 return 0;
430 }
431
432 static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
433 {
434 unsigned char data;
435 int real_pos;
436
437 do {
438 if (pd->pos <= -1) {
439 sh_mobile_i2c_get_data(pd, &data);
440
441 if (sh_mobile_i2c_is_first_byte(pd))
442 i2c_op(pd, OP_TX_FIRST, data);
443 else
444 i2c_op(pd, OP_TX, data);
445 break;
446 }
447
448 if (pd->pos == 0) {
449 i2c_op(pd, OP_TX_TO_RX, 0);
450 break;
451 }
452
453 real_pos = pd->pos - 2;
454
455 if (pd->pos == pd->msg->len) {
456 if (pd->stop_after_dma) {
457 /* Simulate PIO end condition after DMA transfer */
458 i2c_op(pd, OP_RX_STOP, 0);
459 pd->pos++;
460 break;
461 }
462
463 if (real_pos < 0) {
464 i2c_op(pd, OP_RX_STOP, 0);
465 break;
466 }
467 data = i2c_op(pd, OP_RX_STOP_DATA, 0);
468 } else
469 data = i2c_op(pd, OP_RX, 0);
470
471 if (real_pos >= 0)
472 pd->msg->buf[real_pos] = data;
473 } while (0);
474
475 pd->pos++;
476 return pd->pos == (pd->msg->len + 2);
477 }
478
479 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
480 {
481 struct sh_mobile_i2c_data *pd = dev_id;
482 unsigned char sr;
483 int wakeup = 0;
484
485 sr = iic_rd(pd, ICSR);
486 pd->sr |= sr; /* remember state */
487
488 dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
489 (pd->msg->flags & I2C_M_RD) ? "read" : "write",
490 pd->pos, pd->msg->len);
491
492 /* Kick off TxDMA after preface was done */
493 if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0)
494 iic_set_clr(pd, ICIC, ICIC_TDMAE, 0);
495 else if (sr & (ICSR_AL | ICSR_TACK))
496 /* don't interrupt transaction - continue to issue stop */
497 iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK));
498 else if (pd->msg->flags & I2C_M_RD)
499 wakeup = sh_mobile_i2c_isr_rx(pd);
500 else
501 wakeup = sh_mobile_i2c_isr_tx(pd);
502
503 /* Kick off RxDMA after preface was done */
504 if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1)
505 iic_set_clr(pd, ICIC, ICIC_RDMAE, 0);
506
507 if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
508 iic_wr(pd, ICSR, sr & ~ICSR_WAIT);
509
510 if (wakeup) {
511 pd->sr |= SW_DONE;
512 wake_up(&pd->wait);
513 }
514
515 /* defeat write posting to avoid spurious WAIT interrupts */
516 iic_rd(pd, ICSR);
517
518 return IRQ_HANDLED;
519 }
520
521 static void sh_mobile_i2c_dma_unmap(struct sh_mobile_i2c_data *pd)
522 {
523 struct dma_chan *chan = pd->dma_direction == DMA_FROM_DEVICE
524 ? pd->dma_rx : pd->dma_tx;
525
526 dma_unmap_single(chan->device->dev, sg_dma_address(&pd->sg),
527 pd->msg->len, pd->dma_direction);
528
529 pd->dma_direction = DMA_NONE;
530 }
531
532 static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd)
533 {
534 if (pd->dma_direction == DMA_NONE)
535 return;
536 else if (pd->dma_direction == DMA_FROM_DEVICE)
537 dmaengine_terminate_all(pd->dma_rx);
538 else if (pd->dma_direction == DMA_TO_DEVICE)
539 dmaengine_terminate_all(pd->dma_tx);
540
541 sh_mobile_i2c_dma_unmap(pd);
542 }
543
544 static void sh_mobile_i2c_dma_callback(void *data)
545 {
546 struct sh_mobile_i2c_data *pd = data;
547
548 sh_mobile_i2c_dma_unmap(pd);
549 pd->pos = pd->msg->len;
550 pd->stop_after_dma = true;
551
552 iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE);
553 }
554
555 static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev,
556 enum dma_transfer_direction dir, dma_addr_t port_addr)
557 {
558 struct dma_chan *chan;
559 struct dma_slave_config cfg;
560 char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
561 int ret;
562
563 chan = dma_request_slave_channel_reason(dev, chan_name);
564 if (IS_ERR(chan)) {
565 ret = PTR_ERR(chan);
566 dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret);
567 return chan;
568 }
569
570 memset(&cfg, 0, sizeof(cfg));
571 cfg.direction = dir;
572 if (dir == DMA_MEM_TO_DEV) {
573 cfg.dst_addr = port_addr;
574 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
575 } else {
576 cfg.src_addr = port_addr;
577 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
578 }
579
580 ret = dmaengine_slave_config(chan, &cfg);
581 if (ret) {
582 dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret);
583 dma_release_channel(chan);
584 return ERR_PTR(ret);
585 }
586
587 dev_dbg(dev, "got DMA channel for %s\n", chan_name);
588 return chan;
589 }
590
591 static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
592 {
593 bool read = pd->msg->flags & I2C_M_RD;
594 enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
595 struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx;
596 struct dma_async_tx_descriptor *txdesc;
597 dma_addr_t dma_addr;
598 dma_cookie_t cookie;
599
600 if (PTR_ERR(chan) == -EPROBE_DEFER) {
601 if (read)
602 chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM,
603 pd->res->start + ICDR);
604 else
605 chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV,
606 pd->res->start + ICDR);
607 }
608
609 if (IS_ERR(chan))
610 return;
611
612 dma_addr = dma_map_single(chan->device->dev, pd->msg->buf, pd->msg->len, dir);
613 if (dma_mapping_error(chan->device->dev, dma_addr)) {
614 dev_dbg(pd->dev, "dma map failed, using PIO\n");
615 return;
616 }
617
618 sg_dma_len(&pd->sg) = pd->msg->len;
619 sg_dma_address(&pd->sg) = dma_addr;
620
621 pd->dma_direction = dir;
622
623 txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1,
624 read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
625 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
626 if (!txdesc) {
627 dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n");
628 sh_mobile_i2c_cleanup_dma(pd);
629 return;
630 }
631
632 txdesc->callback = sh_mobile_i2c_dma_callback;
633 txdesc->callback_param = pd;
634
635 cookie = dmaengine_submit(txdesc);
636 if (dma_submit_error(cookie)) {
637 dev_dbg(pd->dev, "submitting dma failed, using PIO\n");
638 sh_mobile_i2c_cleanup_dma(pd);
639 return;
640 }
641
642 dma_async_issue_pending(chan);
643 }
644
645 static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
646 bool do_init)
647 {
648 if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
649 dev_err(pd->dev, "Unsupported zero length i2c read\n");
650 return -EOPNOTSUPP;
651 }
652
653 if (do_init) {
654 /* Initialize channel registers */
655 iic_set_clr(pd, ICCR, 0, ICCR_ICE);
656
657 /* Enable channel and configure rx ack */
658 iic_set_clr(pd, ICCR, ICCR_ICE, 0);
659
660 /* Set the clock */
661 iic_wr(pd, ICCL, pd->iccl & 0xff);
662 iic_wr(pd, ICCH, pd->icch & 0xff);
663 }
664
665 pd->msg = usr_msg;
666 pd->pos = -1;
667 pd->sr = 0;
668
669 if (pd->msg->len > 8)
670 sh_mobile_i2c_xfer_dma(pd);
671
672 /* Enable all interrupts to begin with */
673 iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
674 return 0;
675 }
676
677 static int poll_dte(struct sh_mobile_i2c_data *pd)
678 {
679 int i;
680
681 for (i = 1000; i; i--) {
682 u_int8_t val = iic_rd(pd, ICSR);
683
684 if (val & ICSR_DTE)
685 break;
686
687 if (val & ICSR_TACK)
688 return -ENXIO;
689
690 udelay(10);
691 }
692
693 return i ? 0 : -ETIMEDOUT;
694 }
695
696 static int poll_busy(struct sh_mobile_i2c_data *pd)
697 {
698 int i;
699
700 for (i = 1000; i; i--) {
701 u_int8_t val = iic_rd(pd, ICSR);
702
703 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
704
705 /* the interrupt handler may wake us up before the
706 * transfer is finished, so poll the hardware
707 * until we're done.
708 */
709 if (!(val & ICSR_BUSY)) {
710 /* handle missing acknowledge and arbitration lost */
711 val |= pd->sr;
712 if (val & ICSR_TACK)
713 return -ENXIO;
714 if (val & ICSR_AL)
715 return -EAGAIN;
716 break;
717 }
718
719 udelay(10);
720 }
721
722 return i ? 0 : -ETIMEDOUT;
723 }
724
725 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
726 struct i2c_msg *msgs,
727 int num)
728 {
729 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
730 struct i2c_msg *msg;
731 int err = 0;
732 int i;
733 long timeout;
734
735 activate_ch(pd);
736
737 /* Process all messages */
738 for (i = 0; i < num; i++) {
739 bool do_start = pd->send_stop || !i;
740 msg = &msgs[i];
741 pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP;
742 pd->stop_after_dma = false;
743
744 err = start_ch(pd, msg, do_start);
745 if (err)
746 break;
747
748 if (do_start)
749 i2c_op(pd, OP_START, 0);
750
751 /* The interrupt handler takes care of the rest... */
752 timeout = wait_event_timeout(pd->wait,
753 pd->sr & (ICSR_TACK | SW_DONE),
754 adapter->timeout);
755 if (!timeout) {
756 dev_err(pd->dev, "Transfer request timed out\n");
757 if (pd->dma_direction != DMA_NONE)
758 sh_mobile_i2c_cleanup_dma(pd);
759
760 err = -ETIMEDOUT;
761 break;
762 }
763
764 if (pd->send_stop)
765 err = poll_busy(pd);
766 else
767 err = poll_dte(pd);
768 if (err < 0)
769 break;
770 }
771
772 deactivate_ch(pd);
773
774 if (!err)
775 err = num;
776 return err;
777 }
778
779 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
780 {
781 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
782 }
783
784 static struct i2c_algorithm sh_mobile_i2c_algorithm = {
785 .functionality = sh_mobile_i2c_func,
786 .master_xfer = sh_mobile_i2c_xfer,
787 };
788
789 /*
790 * r8a7740 chip has lasting errata on I2C I/O pad reset.
791 * this is work-around for it.
792 */
793 static void sh_mobile_i2c_r8a7740_workaround(struct sh_mobile_i2c_data *pd)
794 {
795 iic_set_clr(pd, ICCR, ICCR_ICE, 0);
796 iic_rd(pd, ICCR); /* dummy read */
797
798 iic_set_clr(pd, ICSTART, ICSTART_ICSTART, 0);
799 iic_rd(pd, ICSTART); /* dummy read */
800
801 udelay(10);
802
803 iic_wr(pd, ICCR, ICCR_SCP);
804 iic_wr(pd, ICSTART, 0);
805
806 udelay(10);
807
808 iic_wr(pd, ICCR, ICCR_TRS);
809 udelay(10);
810 iic_wr(pd, ICCR, 0);
811 udelay(10);
812 iic_wr(pd, ICCR, ICCR_TRS);
813 udelay(10);
814 }
815
816 static const struct sh_mobile_dt_config default_dt_config = {
817 .clks_per_count = 1,
818 };
819
820 static const struct sh_mobile_dt_config fast_clock_dt_config = {
821 .clks_per_count = 2,
822 };
823
824 static const struct sh_mobile_dt_config r8a7740_dt_config = {
825 .clks_per_count = 1,
826 .setup = sh_mobile_i2c_r8a7740_workaround,
827 };
828
829 static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
830 { .compatible = "renesas,rmobile-iic", .data = &default_dt_config },
831 { .compatible = "renesas,iic-r8a73a4", .data = &fast_clock_dt_config },
832 { .compatible = "renesas,iic-r8a7740", .data = &r8a7740_dt_config },
833 { .compatible = "renesas,iic-r8a7790", .data = &fast_clock_dt_config },
834 { .compatible = "renesas,iic-r8a7791", .data = &fast_clock_dt_config },
835 { .compatible = "renesas,iic-r8a7792", .data = &fast_clock_dt_config },
836 { .compatible = "renesas,iic-r8a7793", .data = &fast_clock_dt_config },
837 { .compatible = "renesas,iic-r8a7794", .data = &fast_clock_dt_config },
838 { .compatible = "renesas,iic-r8a7795", .data = &fast_clock_dt_config },
839 { .compatible = "renesas,iic-sh73a0", .data = &fast_clock_dt_config },
840 {},
841 };
842 MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids);
843
844 static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd)
845 {
846 if (!IS_ERR(pd->dma_tx)) {
847 dma_release_channel(pd->dma_tx);
848 pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
849 }
850
851 if (!IS_ERR(pd->dma_rx)) {
852 dma_release_channel(pd->dma_rx);
853 pd->dma_rx = ERR_PTR(-EPROBE_DEFER);
854 }
855 }
856
857 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, struct sh_mobile_i2c_data *pd)
858 {
859 struct resource *res;
860 resource_size_t n;
861 int k = 0, ret;
862
863 while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
864 for (n = res->start; n <= res->end; n++) {
865 ret = devm_request_irq(&dev->dev, n, sh_mobile_i2c_isr,
866 0, dev_name(&dev->dev), pd);
867 if (ret) {
868 dev_err(&dev->dev, "cannot request IRQ %pa\n", &n);
869 return ret;
870 }
871 }
872 k++;
873 }
874
875 return k > 0 ? 0 : -ENOENT;
876 }
877
878 static int sh_mobile_i2c_probe(struct platform_device *dev)
879 {
880 struct i2c_sh_mobile_platform_data *pdata = dev_get_platdata(&dev->dev);
881 struct sh_mobile_i2c_data *pd;
882 struct i2c_adapter *adap;
883 struct resource *res;
884 int ret;
885 u32 bus_speed;
886
887 pd = devm_kzalloc(&dev->dev, sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
888 if (!pd)
889 return -ENOMEM;
890
891 pd->clk = devm_clk_get(&dev->dev, NULL);
892 if (IS_ERR(pd->clk)) {
893 dev_err(&dev->dev, "cannot get clock\n");
894 return PTR_ERR(pd->clk);
895 }
896
897 ret = sh_mobile_i2c_hook_irqs(dev, pd);
898 if (ret)
899 return ret;
900
901 pd->dev = &dev->dev;
902 platform_set_drvdata(dev, pd);
903
904 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
905
906 pd->res = res;
907 pd->reg = devm_ioremap_resource(&dev->dev, res);
908 if (IS_ERR(pd->reg))
909 return PTR_ERR(pd->reg);
910
911 /* Use platform data bus speed or STANDARD_MODE */
912 ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed);
913 pd->bus_speed = ret ? STANDARD_MODE : bus_speed;
914
915 pd->clks_per_count = 1;
916
917 if (dev->dev.of_node) {
918 const struct of_device_id *match;
919
920 match = of_match_device(sh_mobile_i2c_dt_ids, &dev->dev);
921 if (match) {
922 const struct sh_mobile_dt_config *config;
923
924 config = match->data;
925 pd->clks_per_count = config->clks_per_count;
926
927 if (config->setup)
928 config->setup(pd);
929 }
930 } else {
931 if (pdata && pdata->bus_speed)
932 pd->bus_speed = pdata->bus_speed;
933 if (pdata && pdata->clks_per_count)
934 pd->clks_per_count = pdata->clks_per_count;
935 }
936
937 /* The IIC blocks on SH-Mobile ARM processors
938 * come with two new bits in ICIC.
939 */
940 if (resource_size(res) > 0x17)
941 pd->flags |= IIC_FLAG_HAS_ICIC67;
942
943 ret = sh_mobile_i2c_init(pd);
944 if (ret)
945 return ret;
946
947 /* Init DMA */
948 sg_init_table(&pd->sg, 1);
949 pd->dma_direction = DMA_NONE;
950 pd->dma_rx = pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
951
952 /* Enable Runtime PM for this device.
953 *
954 * Also tell the Runtime PM core to ignore children
955 * for this device since it is valid for us to suspend
956 * this I2C master driver even though the slave devices
957 * on the I2C bus may not be suspended.
958 *
959 * The state of the I2C hardware bus is unaffected by
960 * the Runtime PM state.
961 */
962 pm_suspend_ignore_children(&dev->dev, true);
963 pm_runtime_enable(&dev->dev);
964
965 /* setup the private data */
966 adap = &pd->adap;
967 i2c_set_adapdata(adap, pd);
968
969 adap->owner = THIS_MODULE;
970 adap->algo = &sh_mobile_i2c_algorithm;
971 adap->dev.parent = &dev->dev;
972 adap->retries = 5;
973 adap->nr = dev->id;
974 adap->dev.of_node = dev->dev.of_node;
975
976 strlcpy(adap->name, dev->name, sizeof(adap->name));
977
978 spin_lock_init(&pd->lock);
979 init_waitqueue_head(&pd->wait);
980
981 ret = i2c_add_numbered_adapter(adap);
982 if (ret < 0) {
983 sh_mobile_i2c_release_dma(pd);
984 return ret;
985 }
986
987 dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed);
988
989 return 0;
990 }
991
992 static int sh_mobile_i2c_remove(struct platform_device *dev)
993 {
994 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
995
996 i2c_del_adapter(&pd->adap);
997 sh_mobile_i2c_release_dma(pd);
998 pm_runtime_disable(&dev->dev);
999 return 0;
1000 }
1001
1002 static int sh_mobile_i2c_runtime_nop(struct device *dev)
1003 {
1004 /* Runtime PM callback shared between ->runtime_suspend()
1005 * and ->runtime_resume(). Simply returns success.
1006 *
1007 * This driver re-initializes all registers after
1008 * pm_runtime_get_sync() anyway so there is no need
1009 * to save and restore registers here.
1010 */
1011 return 0;
1012 }
1013
1014 static const struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = {
1015 .runtime_suspend = sh_mobile_i2c_runtime_nop,
1016 .runtime_resume = sh_mobile_i2c_runtime_nop,
1017 };
1018
1019 static struct platform_driver sh_mobile_i2c_driver = {
1020 .driver = {
1021 .name = "i2c-sh_mobile",
1022 .pm = &sh_mobile_i2c_dev_pm_ops,
1023 .of_match_table = sh_mobile_i2c_dt_ids,
1024 },
1025 .probe = sh_mobile_i2c_probe,
1026 .remove = sh_mobile_i2c_remove,
1027 };
1028
1029 static int __init sh_mobile_i2c_adap_init(void)
1030 {
1031 return platform_driver_register(&sh_mobile_i2c_driver);
1032 }
1033 subsys_initcall(sh_mobile_i2c_adap_init);
1034
1035 static void __exit sh_mobile_i2c_adap_exit(void)
1036 {
1037 platform_driver_unregister(&sh_mobile_i2c_driver);
1038 }
1039 module_exit(sh_mobile_i2c_adap_exit);
1040
1041 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
1042 MODULE_AUTHOR("Magnus Damm and Wolfram Sang");
1043 MODULE_LICENSE("GPL v2");
1044 MODULE_ALIAS("platform:i2c-sh_mobile");
Linux with added FPC-III support