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Merge branch 'work.regset' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
[linux/fpc-iii.git] / drivers / i2c / busses / i2c-sh_mobile.c
blob2cca1b21e26e80531d6997a09232973762f0aaf2
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * SuperH Mobile I2C Controller
4 *
5 * Copyright (C) 2014-19 Wolfram Sang <wsa@sang-engineering.com>
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
12 #include <linux/clk.h>
13 #include <linux/delay.h>
14 #include <linux/dmaengine.h>
15 #include <linux/dma-mapping.h>
16 #include <linux/err.h>
17 #include <linux/i2c.h>
18 #include <linux/init.h>
19 #include <linux/interrupt.h>
20 #include <linux/io.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/of_device.h>
24 #include <linux/platform_device.h>
25 #include <linux/pm_runtime.h>
26 #include <linux/slab.h>
27
28 /* Transmit operation: */
29 /* */
30 /* 0 byte transmit */
31 /* BUS: S A8 ACK P(*) */
32 /* IRQ: DTE WAIT */
33 /* ICIC: */
34 /* ICCR: 0x94 0x90 */
35 /* ICDR: A8 */
36 /* */
37 /* 1 byte transmit */
38 /* BUS: S A8 ACK D8(1) ACK P(*) */
39 /* IRQ: DTE WAIT WAIT */
40 /* ICIC: -DTE */
41 /* ICCR: 0x94 0x90 */
42 /* ICDR: A8 D8(1) */
43 /* */
44 /* 2 byte transmit */
45 /* BUS: S A8 ACK D8(1) ACK D8(2) ACK P(*) */
46 /* IRQ: DTE WAIT WAIT WAIT */
47 /* ICIC: -DTE */
48 /* ICCR: 0x94 0x90 */
49 /* ICDR: A8 D8(1) D8(2) */
50 /* */
51 /* 3 bytes or more, +---------+ gets repeated */
52 /* */
53 /* */
54 /* Receive operation: */
55 /* */
56 /* 0 byte receive - not supported since slave may hold SDA low */
57 /* */
58 /* 1 byte receive [TX] | [RX] */
59 /* BUS: S A8 ACK | D8(1) ACK P(*) */
60 /* IRQ: DTE WAIT | WAIT DTE */
61 /* ICIC: -DTE | +DTE */
62 /* ICCR: 0x94 0x81 | 0xc0 */
63 /* ICDR: A8 | D8(1) */
64 /* */
65 /* 2 byte receive [TX]| [RX] */
66 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK P(*) */
67 /* IRQ: DTE WAIT | WAIT WAIT DTE */
68 /* ICIC: -DTE | +DTE */
69 /* ICCR: 0x94 0x81 | 0xc0 */
70 /* ICDR: A8 | D8(1) D8(2) */
71 /* */
72 /* 3 byte receive [TX] | [RX] (*) */
73 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK D8(3) ACK P */
74 /* IRQ: DTE WAIT | WAIT WAIT WAIT DTE */
75 /* ICIC: -DTE | +DTE */
76 /* ICCR: 0x94 0x81 | 0xc0 */
77 /* ICDR: A8 | D8(1) D8(2) D8(3) */
78 /* */
79 /* 4 bytes or more, this part is repeated +---------+ */
80 /* */
81 /* */
82 /* Interrupt order and BUSY flag */
83 /* ___ _ */
84 /* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */
85 /* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */
86 /* */
87 /* S D7 D6 D5 D4 D3 D2 D1 D0 P(*) */
88 /* ___ */
89 /* WAIT IRQ ________________________________/ \___________ */
90 /* TACK IRQ ____________________________________/ \_______ */
91 /* DTE IRQ __________________________________________/ \_ */
92 /* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
93 /* _______________________________________________ */
94 /* BUSY __/ \_ */
95 /* */
96 /* (*) The STOP condition is only sent by the master at the end of the last */
97 /* I2C message or if the I2C_M_STOP flag is set. Similarly, the BUSY bit is */
98 /* only cleared after the STOP condition, so, between messages we have to */
99 /* poll for the DTE bit. */
100 /* */
101
102 enum sh_mobile_i2c_op {
103 OP_START = 0,
104 OP_TX_FIRST,
105 OP_TX,
106 OP_TX_STOP,
107 OP_TX_TO_RX,
108 OP_RX,
109 OP_RX_STOP,
110 OP_RX_STOP_DATA,
111 };
112
113 struct sh_mobile_i2c_data {
114 struct device *dev;
115 void __iomem *reg;
116 struct i2c_adapter adap;
117 unsigned long bus_speed;
118 unsigned int clks_per_count;
119 struct clk *clk;
120 u_int8_t icic;
121 u_int8_t flags;
122 u_int16_t iccl;
123 u_int16_t icch;
124
125 spinlock_t lock;
126 wait_queue_head_t wait;
127 struct i2c_msg *msg;
128 int pos;
129 int sr;
130 bool send_stop;
131 bool stop_after_dma;
132
133 struct resource *res;
134 struct dma_chan *dma_tx;
135 struct dma_chan *dma_rx;
136 struct scatterlist sg;
137 enum dma_data_direction dma_direction;
138 u8 *dma_buf;
139 };
140
141 struct sh_mobile_dt_config {
142 int clks_per_count;
143 int (*setup)(struct sh_mobile_i2c_data *pd);
144 };
145
146 #define IIC_FLAG_HAS_ICIC67 (1 << 0)
147
148 /* Register offsets */
149 #define ICDR 0x00
150 #define ICCR 0x04
151 #define ICSR 0x08
152 #define ICIC 0x0c
153 #define ICCL 0x10
154 #define ICCH 0x14
155 #define ICSTART 0x70
156
157 /* Register bits */
158 #define ICCR_ICE 0x80
159 #define ICCR_RACK 0x40
160 #define ICCR_TRS 0x10
161 #define ICCR_BBSY 0x04
162 #define ICCR_SCP 0x01
163
164 #define ICSR_SCLM 0x80
165 #define ICSR_SDAM 0x40
166 #define SW_DONE 0x20
167 #define ICSR_BUSY 0x10
168 #define ICSR_AL 0x08
169 #define ICSR_TACK 0x04
170 #define ICSR_WAIT 0x02
171 #define ICSR_DTE 0x01
172
173 #define ICIC_ICCLB8 0x80
174 #define ICIC_ICCHB8 0x40
175 #define ICIC_TDMAE 0x20
176 #define ICIC_RDMAE 0x10
177 #define ICIC_ALE 0x08
178 #define ICIC_TACKE 0x04
179 #define ICIC_WAITE 0x02
180 #define ICIC_DTEE 0x01
181
182 #define ICSTART_ICSTART 0x10
183
184 static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data)
185 {
186 if (offs == ICIC)
187 data |= pd->icic;
188
189 iowrite8(data, pd->reg + offs);
190 }
191
192 static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs)
193 {
194 return ioread8(pd->reg + offs);
195 }
196
197 static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs,
198 unsigned char set, unsigned char clr)
199 {
200 iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr);
201 }
202
203 static u32 sh_mobile_i2c_iccl(unsigned long count_khz, u32 tLOW, u32 tf)
204 {
205 /*
206 * Conditional expression:
207 * ICCL >= COUNT_CLK * (tLOW + tf)
208 *
209 * SH-Mobile IIC hardware starts counting the LOW period of
210 * the SCL signal (tLOW) as soon as it pulls the SCL line.
211 * In order to meet the tLOW timing spec, we need to take into
212 * account the fall time of SCL signal (tf). Default tf value
213 * should be 0.3 us, for safety.
214 */
215 return (((count_khz * (tLOW + tf)) + 5000) / 10000);
216 }
217
218 static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf)
219 {
220 /*
221 * Conditional expression:
222 * ICCH >= COUNT_CLK * (tHIGH + tf)
223 *
224 * SH-Mobile IIC hardware is aware of SCL transition period 'tr',
225 * and can ignore it. SH-Mobile IIC controller starts counting
226 * the HIGH period of the SCL signal (tHIGH) after the SCL input
227 * voltage increases at VIH.
228 *
229 * Afterward it turned out calculating ICCH using only tHIGH spec
230 * will result in violation of the tHD;STA timing spec. We need
231 * to take into account the fall time of SDA signal (tf) at START
232 * condition, in order to meet both tHIGH and tHD;STA specs.
233 */
234 return (((count_khz * (tHIGH + tf)) + 5000) / 10000);
235 }
236
237 static int sh_mobile_i2c_check_timing(struct sh_mobile_i2c_data *pd)
238 {
239 u16 max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff;
240
241 if (pd->iccl > max_val || pd->icch > max_val) {
242 dev_err(pd->dev, "timing values out of range: L/H=0x%x/0x%x\n",
243 pd->iccl, pd->icch);
244 return -EINVAL;
245 }
246
247 /* one more bit of ICCL in ICIC */
248 if (pd->iccl & 0x100)
249 pd->icic |= ICIC_ICCLB8;
250 else
251 pd->icic &= ~ICIC_ICCLB8;
252
253 /* one more bit of ICCH in ICIC */
254 if (pd->icch & 0x100)
255 pd->icic |= ICIC_ICCHB8;
256 else
257 pd->icic &= ~ICIC_ICCHB8;
258
259 dev_dbg(pd->dev, "timing values: L/H=0x%x/0x%x\n", pd->iccl, pd->icch);
260 return 0;
261 }
262
263 static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
264 {
265 unsigned long i2c_clk_khz;
266 u32 tHIGH, tLOW, tf;
267
268 i2c_clk_khz = clk_get_rate(pd->clk) / 1000 / pd->clks_per_count;
269
270 if (pd->bus_speed == I2C_MAX_STANDARD_MODE_FREQ) {
271 tLOW = 47; /* tLOW = 4.7 us */
272 tHIGH = 40; /* tHD;STA = tHIGH = 4.0 us */
273 tf = 3; /* tf = 0.3 us */
274 } else if (pd->bus_speed == I2C_MAX_FAST_MODE_FREQ) {
275 tLOW = 13; /* tLOW = 1.3 us */
276 tHIGH = 6; /* tHD;STA = tHIGH = 0.6 us */
277 tf = 3; /* tf = 0.3 us */
278 } else {
279 dev_err(pd->dev, "unrecognized bus speed %lu Hz\n",
280 pd->bus_speed);
281 return -EINVAL;
282 }
283
284 pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf);
285 pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf);
286
287 return sh_mobile_i2c_check_timing(pd);
288 }
289
290 static int sh_mobile_i2c_v2_init(struct sh_mobile_i2c_data *pd)
291 {
292 unsigned long clks_per_cycle;
293
294 /* L = 5, H = 4, L + H = 9 */
295 clks_per_cycle = clk_get_rate(pd->clk) / pd->bus_speed;
296 pd->iccl = DIV_ROUND_UP(clks_per_cycle * 5 / 9 - 1, pd->clks_per_count);
297 pd->icch = DIV_ROUND_UP(clks_per_cycle * 4 / 9 - 5, pd->clks_per_count);
298
299 return sh_mobile_i2c_check_timing(pd);
300 }
301
302 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd, enum sh_mobile_i2c_op op)
303 {
304 unsigned char ret = 0;
305 unsigned long flags;
306
307 dev_dbg(pd->dev, "op %d\n", op);
308
309 spin_lock_irqsave(&pd->lock, flags);
310
311 switch (op) {
312 case OP_START: /* issue start and trigger DTE interrupt */
313 iic_wr(pd, ICCR, ICCR_ICE | ICCR_TRS | ICCR_BBSY);
314 break;
315 case OP_TX_FIRST: /* disable DTE interrupt and write client address */
316 iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
317 iic_wr(pd, ICDR, i2c_8bit_addr_from_msg(pd->msg));
318 break;
319 case OP_TX: /* write data */
320 iic_wr(pd, ICDR, pd->msg->buf[pd->pos]);
321 break;
322 case OP_TX_STOP: /* issue a stop (or rep_start) */
323 iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS
324 : ICCR_ICE | ICCR_TRS | ICCR_BBSY);
325 break;
326 case OP_TX_TO_RX: /* select read mode */
327 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP);
328 break;
329 case OP_RX: /* just read data */
330 ret = iic_rd(pd, ICDR);
331 break;
332 case OP_RX_STOP: /* enable DTE interrupt, issue stop */
333 iic_wr(pd, ICIC,
334 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
335 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
336 break;
337 case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
338 iic_wr(pd, ICIC,
339 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
340 ret = iic_rd(pd, ICDR);
341 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
342 break;
343 }
344
345 spin_unlock_irqrestore(&pd->lock, flags);
346
347 dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
348 return ret;
349 }
350
351 static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
352 {
353 if (pd->pos == pd->msg->len) {
354 i2c_op(pd, OP_TX_STOP);
355 return 1;
356 }
357
358 if (pd->pos == -1)
359 i2c_op(pd, OP_TX_FIRST);
360 else
361 i2c_op(pd, OP_TX);
362
363 pd->pos++;
364 return 0;
365 }
366
367 static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
368 {
369 int real_pos;
370
371 /* switch from TX (address) to RX (data) adds two interrupts */
372 real_pos = pd->pos - 2;
373
374 if (pd->pos == -1) {
375 i2c_op(pd, OP_TX_FIRST);
376 } else if (pd->pos == 0) {
377 i2c_op(pd, OP_TX_TO_RX);
378 } else if (pd->pos == pd->msg->len) {
379 if (pd->stop_after_dma) {
380 /* Simulate PIO end condition after DMA transfer */
381 i2c_op(pd, OP_RX_STOP);
382 pd->pos++;
383 goto done;
384 }
385
386 if (real_pos < 0)
387 i2c_op(pd, OP_RX_STOP);
388 else
389 pd->msg->buf[real_pos] = i2c_op(pd, OP_RX_STOP_DATA);
390 } else if (real_pos >= 0) {
391 pd->msg->buf[real_pos] = i2c_op(pd, OP_RX);
392 }
393
394 done:
395 pd->pos++;
396 return pd->pos == (pd->msg->len + 2);
397 }
398
399 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
400 {
401 struct sh_mobile_i2c_data *pd = dev_id;
402 unsigned char sr;
403 int wakeup = 0;
404
405 sr = iic_rd(pd, ICSR);
406 pd->sr |= sr; /* remember state */
407
408 dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
409 (pd->msg->flags & I2C_M_RD) ? "read" : "write",
410 pd->pos, pd->msg->len);
411
412 /* Kick off TxDMA after preface was done */
413 if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0)
414 iic_set_clr(pd, ICIC, ICIC_TDMAE, 0);
415 else if (sr & (ICSR_AL | ICSR_TACK))
416 /* don't interrupt transaction - continue to issue stop */
417 iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK));
418 else if (pd->msg->flags & I2C_M_RD)
419 wakeup = sh_mobile_i2c_isr_rx(pd);
420 else
421 wakeup = sh_mobile_i2c_isr_tx(pd);
422
423 /* Kick off RxDMA after preface was done */
424 if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1)
425 iic_set_clr(pd, ICIC, ICIC_RDMAE, 0);
426
427 if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
428 iic_wr(pd, ICSR, sr & ~ICSR_WAIT);
429
430 if (wakeup) {
431 pd->sr |= SW_DONE;
432 wake_up(&pd->wait);
433 }
434
435 /* defeat write posting to avoid spurious WAIT interrupts */
436 iic_rd(pd, ICSR);
437
438 return IRQ_HANDLED;
439 }
440
441 static void sh_mobile_i2c_dma_unmap(struct sh_mobile_i2c_data *pd)
442 {
443 struct dma_chan *chan = pd->dma_direction == DMA_FROM_DEVICE
444 ? pd->dma_rx : pd->dma_tx;
445
446 dma_unmap_single(chan->device->dev, sg_dma_address(&pd->sg),
447 pd->msg->len, pd->dma_direction);
448
449 pd->dma_direction = DMA_NONE;
450 }
451
452 static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd)
453 {
454 if (pd->dma_direction == DMA_NONE)
455 return;
456 else if (pd->dma_direction == DMA_FROM_DEVICE)
457 dmaengine_terminate_all(pd->dma_rx);
458 else if (pd->dma_direction == DMA_TO_DEVICE)
459 dmaengine_terminate_all(pd->dma_tx);
460
461 sh_mobile_i2c_dma_unmap(pd);
462 }
463
464 static void sh_mobile_i2c_dma_callback(void *data)
465 {
466 struct sh_mobile_i2c_data *pd = data;
467
468 sh_mobile_i2c_dma_unmap(pd);
469 pd->pos = pd->msg->len;
470 pd->stop_after_dma = true;
471
472 iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE);
473 }
474
475 static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev,
476 enum dma_transfer_direction dir, dma_addr_t port_addr)
477 {
478 struct dma_chan *chan;
479 struct dma_slave_config cfg;
480 char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
481 int ret;
482
483 chan = dma_request_chan(dev, chan_name);
484 if (IS_ERR(chan)) {
485 dev_dbg(dev, "request_channel failed for %s (%ld)\n", chan_name,
486 PTR_ERR(chan));
487 return chan;
488 }
489
490 memset(&cfg, 0, sizeof(cfg));
491 cfg.direction = dir;
492 if (dir == DMA_MEM_TO_DEV) {
493 cfg.dst_addr = port_addr;
494 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
495 } else {
496 cfg.src_addr = port_addr;
497 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
498 }
499
500 ret = dmaengine_slave_config(chan, &cfg);
501 if (ret) {
502 dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret);
503 dma_release_channel(chan);
504 return ERR_PTR(ret);
505 }
506
507 dev_dbg(dev, "got DMA channel for %s\n", chan_name);
508 return chan;
509 }
510
511 static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
512 {
513 bool read = pd->msg->flags & I2C_M_RD;
514 enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
515 struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx;
516 struct dma_async_tx_descriptor *txdesc;
517 dma_addr_t dma_addr;
518 dma_cookie_t cookie;
519
520 if (PTR_ERR(chan) == -EPROBE_DEFER) {
521 if (read)
522 chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM,
523 pd->res->start + ICDR);
524 else
525 chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV,
526 pd->res->start + ICDR);
527 }
528
529 if (IS_ERR(chan))
530 return;
531
532 dma_addr = dma_map_single(chan->device->dev, pd->dma_buf, pd->msg->len, dir);
533 if (dma_mapping_error(chan->device->dev, dma_addr)) {
534 dev_dbg(pd->dev, "dma map failed, using PIO\n");
535 return;
536 }
537
538 sg_dma_len(&pd->sg) = pd->msg->len;
539 sg_dma_address(&pd->sg) = dma_addr;
540
541 pd->dma_direction = dir;
542
543 txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1,
544 read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
545 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
546 if (!txdesc) {
547 dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n");
548 sh_mobile_i2c_cleanup_dma(pd);
549 return;
550 }
551
552 txdesc->callback = sh_mobile_i2c_dma_callback;
553 txdesc->callback_param = pd;
554
555 cookie = dmaengine_submit(txdesc);
556 if (dma_submit_error(cookie)) {
557 dev_dbg(pd->dev, "submitting dma failed, using PIO\n");
558 sh_mobile_i2c_cleanup_dma(pd);
559 return;
560 }
561
562 dma_async_issue_pending(chan);
563 }
564
565 static void start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
566 bool do_init)
567 {
568 if (do_init) {
569 /* Initialize channel registers */
570 iic_wr(pd, ICCR, ICCR_SCP);
571
572 /* Enable channel and configure rx ack */
573 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP);
574
575 /* Set the clock */
576 iic_wr(pd, ICCL, pd->iccl & 0xff);
577 iic_wr(pd, ICCH, pd->icch & 0xff);
578 }
579
580 pd->msg = usr_msg;
581 pd->pos = -1;
582 pd->sr = 0;
583
584 pd->dma_buf = i2c_get_dma_safe_msg_buf(pd->msg, 8);
585 if (pd->dma_buf)
586 sh_mobile_i2c_xfer_dma(pd);
587
588 /* Enable all interrupts to begin with */
589 iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
590 }
591
592 static int poll_dte(struct sh_mobile_i2c_data *pd)
593 {
594 int i;
595
596 for (i = 1000; i; i--) {
597 u_int8_t val = iic_rd(pd, ICSR);
598
599 if (val & ICSR_DTE)
600 break;
601
602 if (val & ICSR_TACK)
603 return -ENXIO;
604
605 udelay(10);
606 }
607
608 return i ? 0 : -ETIMEDOUT;
609 }
610
611 static int poll_busy(struct sh_mobile_i2c_data *pd)
612 {
613 int i;
614
615 for (i = 1000; i; i--) {
616 u_int8_t val = iic_rd(pd, ICSR);
617
618 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
619
620 /* the interrupt handler may wake us up before the
621 * transfer is finished, so poll the hardware
622 * until we're done.
623 */
624 if (!(val & ICSR_BUSY)) {
625 /* handle missing acknowledge and arbitration lost */
626 val |= pd->sr;
627 if (val & ICSR_TACK)
628 return -ENXIO;
629 if (val & ICSR_AL)
630 return -EAGAIN;
631 break;
632 }
633
634 udelay(10);
635 }
636
637 return i ? 0 : -ETIMEDOUT;
638 }
639
640 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
641 struct i2c_msg *msgs,
642 int num)
643 {
644 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
645 struct i2c_msg *msg;
646 int err = 0;
647 int i;
648 long timeout;
649
650 /* Wake up device and enable clock */
651 pm_runtime_get_sync(pd->dev);
652
653 /* Process all messages */
654 for (i = 0; i < num; i++) {
655 bool do_start = pd->send_stop || !i;
656 msg = &msgs[i];
657 pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP;
658 pd->stop_after_dma = false;
659
660 start_ch(pd, msg, do_start);
661
662 if (do_start)
663 i2c_op(pd, OP_START);
664
665 /* The interrupt handler takes care of the rest... */
666 timeout = wait_event_timeout(pd->wait,
667 pd->sr & (ICSR_TACK | SW_DONE),
668 adapter->timeout);
669
670 /* 'stop_after_dma' tells if DMA transfer was complete */
671 i2c_put_dma_safe_msg_buf(pd->dma_buf, pd->msg, pd->stop_after_dma);
672
673 if (!timeout) {
674 dev_err(pd->dev, "Transfer request timed out\n");
675 if (pd->dma_direction != DMA_NONE)
676 sh_mobile_i2c_cleanup_dma(pd);
677
678 err = -ETIMEDOUT;
679 break;
680 }
681
682 if (pd->send_stop)
683 err = poll_busy(pd);
684 else
685 err = poll_dte(pd);
686 if (err < 0)
687 break;
688 }
689
690 /* Disable channel */
691 iic_wr(pd, ICCR, ICCR_SCP);
692
693 /* Disable clock and mark device as idle */
694 pm_runtime_put_sync(pd->dev);
695
696 return err ?: num;
697 }
698
699 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
700 {
701 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
702 }
703
704 static const struct i2c_algorithm sh_mobile_i2c_algorithm = {
705 .functionality = sh_mobile_i2c_func,
706 .master_xfer = sh_mobile_i2c_xfer,
707 };
708
709 static const struct i2c_adapter_quirks sh_mobile_i2c_quirks = {
710 .flags = I2C_AQ_NO_ZERO_LEN_READ,
711 };
712
713 /*
714 * r8a7740 has an errata regarding I2C I/O pad reset needing this workaround.
715 */
716 static int sh_mobile_i2c_r8a7740_workaround(struct sh_mobile_i2c_data *pd)
717 {
718 iic_set_clr(pd, ICCR, ICCR_ICE, 0);
719 iic_rd(pd, ICCR); /* dummy read */
720
721 iic_set_clr(pd, ICSTART, ICSTART_ICSTART, 0);
722 iic_rd(pd, ICSTART); /* dummy read */
723
724 udelay(10);
725
726 iic_wr(pd, ICCR, ICCR_SCP);
727 iic_wr(pd, ICSTART, 0);
728
729 udelay(10);
730
731 iic_wr(pd, ICCR, ICCR_TRS);
732 udelay(10);
733 iic_wr(pd, ICCR, 0);
734 udelay(10);
735 iic_wr(pd, ICCR, ICCR_TRS);
736 udelay(10);
737
738 return sh_mobile_i2c_init(pd);
739 }
740
741 static const struct sh_mobile_dt_config default_dt_config = {
742 .clks_per_count = 1,
743 .setup = sh_mobile_i2c_init,
744 };
745
746 static const struct sh_mobile_dt_config fast_clock_dt_config = {
747 .clks_per_count = 2,
748 .setup = sh_mobile_i2c_init,
749 };
750
751 static const struct sh_mobile_dt_config v2_freq_calc_dt_config = {
752 .clks_per_count = 2,
753 .setup = sh_mobile_i2c_v2_init,
754 };
755
756 static const struct sh_mobile_dt_config r8a7740_dt_config = {
757 .clks_per_count = 1,
758 .setup = sh_mobile_i2c_r8a7740_workaround,
759 };
760
761 static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
762 { .compatible = "renesas,iic-r8a73a4", .data = &fast_clock_dt_config },
763 { .compatible = "renesas,iic-r8a7740", .data = &r8a7740_dt_config },
764 { .compatible = "renesas,iic-r8a774c0", .data = &fast_clock_dt_config },
765 { .compatible = "renesas,iic-r8a7790", .data = &v2_freq_calc_dt_config },
766 { .compatible = "renesas,iic-r8a7791", .data = &v2_freq_calc_dt_config },
767 { .compatible = "renesas,iic-r8a7792", .data = &v2_freq_calc_dt_config },
768 { .compatible = "renesas,iic-r8a7793", .data = &v2_freq_calc_dt_config },
769 { .compatible = "renesas,iic-r8a7794", .data = &v2_freq_calc_dt_config },
770 { .compatible = "renesas,iic-r8a7795", .data = &v2_freq_calc_dt_config },
771 { .compatible = "renesas,iic-r8a77990", .data = &v2_freq_calc_dt_config },
772 { .compatible = "renesas,iic-sh73a0", .data = &fast_clock_dt_config },
773 { .compatible = "renesas,rcar-gen2-iic", .data = &v2_freq_calc_dt_config },
774 { .compatible = "renesas,rcar-gen3-iic", .data = &v2_freq_calc_dt_config },
775 { .compatible = "renesas,rmobile-iic", .data = &default_dt_config },
776 {},
777 };
778 MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids);
779
780 static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd)
781 {
782 if (!IS_ERR(pd->dma_tx)) {
783 dma_release_channel(pd->dma_tx);
784 pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
785 }
786
787 if (!IS_ERR(pd->dma_rx)) {
788 dma_release_channel(pd->dma_rx);
789 pd->dma_rx = ERR_PTR(-EPROBE_DEFER);
790 }
791 }
792
793 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, struct sh_mobile_i2c_data *pd)
794 {
795 struct resource *res;
796 resource_size_t n;
797 int k = 0, ret;
798
799 while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
800 for (n = res->start; n <= res->end; n++) {
801 ret = devm_request_irq(&dev->dev, n, sh_mobile_i2c_isr,
802 0, dev_name(&dev->dev), pd);
803 if (ret) {
804 dev_err(&dev->dev, "cannot request IRQ %pa\n", &n);
805 return ret;
806 }
807 }
808 k++;
809 }
810
811 return k > 0 ? 0 : -ENOENT;
812 }
813
814 static int sh_mobile_i2c_probe(struct platform_device *dev)
815 {
816 struct sh_mobile_i2c_data *pd;
817 struct i2c_adapter *adap;
818 struct resource *res;
819 const struct sh_mobile_dt_config *config;
820 int ret;
821 u32 bus_speed;
822
823 pd = devm_kzalloc(&dev->dev, sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
824 if (!pd)
825 return -ENOMEM;
826
827 pd->clk = devm_clk_get(&dev->dev, NULL);
828 if (IS_ERR(pd->clk)) {
829 dev_err(&dev->dev, "cannot get clock\n");
830 return PTR_ERR(pd->clk);
831 }
832
833 ret = sh_mobile_i2c_hook_irqs(dev, pd);
834 if (ret)
835 return ret;
836
837 pd->dev = &dev->dev;
838 platform_set_drvdata(dev, pd);
839
840 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
841
842 pd->res = res;
843 pd->reg = devm_ioremap_resource(&dev->dev, res);
844 if (IS_ERR(pd->reg))
845 return PTR_ERR(pd->reg);
846
847 ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed);
848 pd->bus_speed = (ret || !bus_speed) ? I2C_MAX_STANDARD_MODE_FREQ : bus_speed;
849 pd->clks_per_count = 1;
850
851 /* Newer variants come with two new bits in ICIC */
852 if (resource_size(res) > 0x17)
853 pd->flags |= IIC_FLAG_HAS_ICIC67;
854
855 pm_runtime_enable(&dev->dev);
856 pm_runtime_get_sync(&dev->dev);
857
858 config = of_device_get_match_data(&dev->dev);
859 if (config) {
860 pd->clks_per_count = config->clks_per_count;
861 ret = config->setup(pd);
862 } else {
863 ret = sh_mobile_i2c_init(pd);
864 }
865
866 pm_runtime_put_sync(&dev->dev);
867 if (ret)
868 return ret;
869
870 /* Init DMA */
871 sg_init_table(&pd->sg, 1);
872 pd->dma_direction = DMA_NONE;
873 pd->dma_rx = pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
874
875 /* setup the private data */
876 adap = &pd->adap;
877 i2c_set_adapdata(adap, pd);
878
879 adap->owner = THIS_MODULE;
880 adap->algo = &sh_mobile_i2c_algorithm;
881 adap->quirks = &sh_mobile_i2c_quirks;
882 adap->dev.parent = &dev->dev;
883 adap->retries = 5;
884 adap->nr = dev->id;
885 adap->dev.of_node = dev->dev.of_node;
886
887 strlcpy(adap->name, dev->name, sizeof(adap->name));
888
889 spin_lock_init(&pd->lock);
890 init_waitqueue_head(&pd->wait);
891
892 ret = i2c_add_numbered_adapter(adap);
893 if (ret < 0) {
894 sh_mobile_i2c_release_dma(pd);
895 return ret;
896 }
897
898 dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed);
899
900 return 0;
901 }
902
903 static int sh_mobile_i2c_remove(struct platform_device *dev)
904 {
905 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
906
907 i2c_del_adapter(&pd->adap);
908 sh_mobile_i2c_release_dma(pd);
909 pm_runtime_disable(&dev->dev);
910 return 0;
911 }
912
913 static struct platform_driver sh_mobile_i2c_driver = {
914 .driver = {
915 .name = "i2c-sh_mobile",
916 .of_match_table = sh_mobile_i2c_dt_ids,
917 },
918 .probe = sh_mobile_i2c_probe,
919 .remove = sh_mobile_i2c_remove,
920 };
921
922 static int __init sh_mobile_i2c_adap_init(void)
923 {
924 return platform_driver_register(&sh_mobile_i2c_driver);
925 }
926 subsys_initcall(sh_mobile_i2c_adap_init);
927
928 static void __exit sh_mobile_i2c_adap_exit(void)
929 {
930 platform_driver_unregister(&sh_mobile_i2c_driver);
931 }
932 module_exit(sh_mobile_i2c_adap_exit);
933
934 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
935 MODULE_AUTHOR("Magnus Damm and Wolfram Sang");
936 MODULE_LICENSE("GPL v2");
937 MODULE_ALIAS("platform:i2c-sh_mobile");
Linux with added FPC-III support