1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * SuperH Mobile I2C Controller
4 *
5 * Copyright (C) 2014 Wolfram Sang <wsa@sang-engineering.com>
6 *
7 * Copyright (C) 2008 Magnus Damm
8 *
9 * Portions of the code based on out-of-tree driver i2c-sh7343.c
10 * Copyright (c) 2006 Carlos Munoz <carlos@kenati.com>
11 */
12
13 #include <linux/clk.h>
14 #include <linux/delay.h>
15 #include <linux/dmaengine.h>
16 #include <linux/dma-mapping.h>
17 #include <linux/err.h>
18 #include <linux/i2c.h>
19 #include <linux/init.h>
20 #include <linux/interrupt.h>
21 #include <linux/io.h>
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/of_device.h>
25 #include <linux/platform_device.h>
26 #include <linux/pm_runtime.h>
27 #include <linux/slab.h>
28
29 /* Transmit operation: */
30 /* */
31 /* 0 byte transmit */
32 /* BUS: S A8 ACK P(*) */
33 /* IRQ: DTE WAIT */
34 /* ICIC: */
35 /* ICCR: 0x94 0x90 */
36 /* ICDR: A8 */
37 /* */
38 /* 1 byte transmit */
39 /* BUS: S A8 ACK D8(1) ACK P(*) */
40 /* IRQ: DTE WAIT WAIT */
41 /* ICIC: -DTE */
42 /* ICCR: 0x94 0x90 */
43 /* ICDR: A8 D8(1) */
44 /* */
45 /* 2 byte transmit */
46 /* BUS: S A8 ACK D8(1) ACK D8(2) ACK P(*) */
47 /* IRQ: DTE WAIT WAIT WAIT */
48 /* ICIC: -DTE */
49 /* ICCR: 0x94 0x90 */
50 /* ICDR: A8 D8(1) D8(2) */
51 /* */
52 /* 3 bytes or more, +---------+ gets repeated */
53 /* */
54 /* */
55 /* Receive operation: */
56 /* */
57 /* 0 byte receive - not supported since slave may hold SDA low */
58 /* */
59 /* 1 byte receive [TX] | [RX] */
60 /* BUS: S A8 ACK | D8(1) ACK P(*) */
61 /* IRQ: DTE WAIT | WAIT DTE */
62 /* ICIC: -DTE | +DTE */
63 /* ICCR: 0x94 0x81 | 0xc0 */
64 /* ICDR: A8 | D8(1) */
65 /* */
66 /* 2 byte receive [TX]| [RX] */
67 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK P(*) */
68 /* IRQ: DTE WAIT | WAIT WAIT DTE */
69 /* ICIC: -DTE | +DTE */
70 /* ICCR: 0x94 0x81 | 0xc0 */
71 /* ICDR: A8 | D8(1) D8(2) */
72 /* */
73 /* 3 byte receive [TX] | [RX] (*) */
74 /* BUS: S A8 ACK | D8(1) ACK D8(2) ACK D8(3) ACK P */
75 /* IRQ: DTE WAIT | WAIT WAIT WAIT DTE */
76 /* ICIC: -DTE | +DTE */
77 /* ICCR: 0x94 0x81 | 0xc0 */
78 /* ICDR: A8 | D8(1) D8(2) D8(3) */
79 /* */
80 /* 4 bytes or more, this part is repeated +---------+ */
81 /* */
82 /* */
83 /* Interrupt order and BUSY flag */
84 /* ___ _ */
85 /* SDA ___\___XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXAAAAAAAAA___/ */
86 /* SCL \_/1\_/2\_/3\_/4\_/5\_/6\_/7\_/8\___/9\_____/ */
87 /* */
88 /* S D7 D6 D5 D4 D3 D2 D1 D0 P(*) */
89 /* ___ */
90 /* WAIT IRQ ________________________________/ \___________ */
91 /* TACK IRQ ____________________________________/ \_______ */
92 /* DTE IRQ __________________________________________/ \_ */
93 /* AL IRQ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX */
94 /* _______________________________________________ */
95 /* BUSY __/ \_ */
96 /* */
97 /* (*) The STOP condition is only sent by the master at the end of the last */
98 /* I2C message or if the I2C_M_STOP flag is set. Similarly, the BUSY bit is */
99 /* only cleared after the STOP condition, so, between messages we have to */
100 /* poll for the DTE bit. */
101 /* */
102
103 enum sh_mobile_i2c_op {
104 OP_START = 0,
105 OP_TX_FIRST,
106 OP_TX,
107 OP_TX_STOP,
108 OP_TX_TO_RX,
109 OP_RX,
110 OP_RX_STOP,
111 OP_RX_STOP_DATA,
112 };
113
114 struct sh_mobile_i2c_data {
115 struct device *dev;
116 void __iomem *reg;
117 struct i2c_adapter adap;
118 unsigned long bus_speed;
119 unsigned int clks_per_count;
120 struct clk *clk;
121 u_int8_t icic;
122 u_int8_t flags;
123 u_int16_t iccl;
124 u_int16_t icch;
125
126 spinlock_t lock;
127 wait_queue_head_t wait;
128 struct i2c_msg *msg;
129 int pos;
130 int sr;
131 bool send_stop;
132 bool stop_after_dma;
133
134 struct resource *res;
135 struct dma_chan *dma_tx;
136 struct dma_chan *dma_rx;
137 struct scatterlist sg;
138 enum dma_data_direction dma_direction;
139 u8 *dma_buf;
140 };
141
142 struct sh_mobile_dt_config {
143 int clks_per_count;
144 int (*setup)(struct sh_mobile_i2c_data *pd);
145 };
146
147 #define IIC_FLAG_HAS_ICIC67 (1 << 0)
148
149 #define STANDARD_MODE 100000
150 #define FAST_MODE 400000
151
152 /* Register offsets */
153 #define ICDR 0x00
154 #define ICCR 0x04
155 #define ICSR 0x08
156 #define ICIC 0x0c
157 #define ICCL 0x10
158 #define ICCH 0x14
159 #define ICSTART 0x70
160
161 /* Register bits */
162 #define ICCR_ICE 0x80
163 #define ICCR_RACK 0x40
164 #define ICCR_TRS 0x10
165 #define ICCR_BBSY 0x04
166 #define ICCR_SCP 0x01
167
168 #define ICSR_SCLM 0x80
169 #define ICSR_SDAM 0x40
170 #define SW_DONE 0x20
171 #define ICSR_BUSY 0x10
172 #define ICSR_AL 0x08
173 #define ICSR_TACK 0x04
174 #define ICSR_WAIT 0x02
175 #define ICSR_DTE 0x01
176
177 #define ICIC_ICCLB8 0x80
178 #define ICIC_ICCHB8 0x40
179 #define ICIC_TDMAE 0x20
180 #define ICIC_RDMAE 0x10
181 #define ICIC_ALE 0x08
182 #define ICIC_TACKE 0x04
183 #define ICIC_WAITE 0x02
184 #define ICIC_DTEE 0x01
185
186 #define ICSTART_ICSTART 0x10
187
iic_wr(struct sh_mobile_i2c_data * pd,int offs,unsigned char data)188 static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data)
189 {
190 if (offs == ICIC)
191 data |= pd->icic;
192
193 iowrite8(data, pd->reg + offs);
194 }
195
iic_rd(struct sh_mobile_i2c_data * pd,int offs)196 static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs)
197 {
198 return ioread8(pd->reg + offs);
199 }
200
iic_set_clr(struct sh_mobile_i2c_data * pd,int offs,unsigned char set,unsigned char clr)201 static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs,
202 unsigned char set, unsigned char clr)
203 {
204 iic_wr(pd, offs, (iic_rd(pd, offs) | set) & ~clr);
205 }
206
sh_mobile_i2c_iccl(unsigned long count_khz,u32 tLOW,u32 tf)207 static u32 sh_mobile_i2c_iccl(unsigned long count_khz, u32 tLOW, u32 tf)
208 {
209 /*
210 * Conditional expression:
211 * ICCL >= COUNT_CLK * (tLOW + tf)
212 *
213 * SH-Mobile IIC hardware starts counting the LOW period of
214 * the SCL signal (tLOW) as soon as it pulls the SCL line.
215 * In order to meet the tLOW timing spec, we need to take into
216 * account the fall time of SCL signal (tf). Default tf value
217 * should be 0.3 us, for safety.
218 */
219 return (((count_khz * (tLOW + tf)) + 5000) / 10000);
220 }
221
sh_mobile_i2c_icch(unsigned long count_khz,u32 tHIGH,u32 tf)222 static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf)
223 {
224 /*
225 * Conditional expression:
226 * ICCH >= COUNT_CLK * (tHIGH + tf)
227 *
228 * SH-Mobile IIC hardware is aware of SCL transition period 'tr',
229 * and can ignore it. SH-Mobile IIC controller starts counting
230 * the HIGH period of the SCL signal (tHIGH) after the SCL input
231 * voltage increases at VIH.
232 *
233 * Afterward it turned out calculating ICCH using only tHIGH spec
234 * will result in violation of the tHD;STA timing spec. We need
235 * to take into account the fall time of SDA signal (tf) at START
236 * condition, in order to meet both tHIGH and tHD;STA specs.
237 */
238 return (((count_khz * (tHIGH + tf)) + 5000) / 10000);
239 }
240
sh_mobile_i2c_check_timing(struct sh_mobile_i2c_data * pd)241 static int sh_mobile_i2c_check_timing(struct sh_mobile_i2c_data *pd)
242 {
243 u16 max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff;
244
245 if (pd->iccl > max_val || pd->icch > max_val) {
246 dev_err(pd->dev, "timing values out of range: L/H=0x%x/0x%x\n",
247 pd->iccl, pd->icch);
248 return -EINVAL;
249 }
250
251 /* one more bit of ICCL in ICIC */
252 if (pd->iccl & 0x100)
253 pd->icic |= ICIC_ICCLB8;
254 else
255 pd->icic &= ~ICIC_ICCLB8;
256
257 /* one more bit of ICCH in ICIC */
258 if (pd->icch & 0x100)
259 pd->icic |= ICIC_ICCHB8;
260 else
261 pd->icic &= ~ICIC_ICCHB8;
262
263 dev_dbg(pd->dev, "timing values: L/H=0x%x/0x%x\n", pd->iccl, pd->icch);
264 return 0;
265 }
266
sh_mobile_i2c_init(struct sh_mobile_i2c_data * pd)267 static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
268 {
269 unsigned long i2c_clk_khz;
270 u32 tHIGH, tLOW, tf;
271
272 i2c_clk_khz = clk_get_rate(pd->clk) / 1000 / pd->clks_per_count;
273
274 if (pd->bus_speed == STANDARD_MODE) {
275 tLOW = 47; /* tLOW = 4.7 us */
276 tHIGH = 40; /* tHD;STA = tHIGH = 4.0 us */
277 tf = 3; /* tf = 0.3 us */
278 } else if (pd->bus_speed == FAST_MODE) {
279 tLOW = 13; /* tLOW = 1.3 us */
280 tHIGH = 6; /* tHD;STA = tHIGH = 0.6 us */
281 tf = 3; /* tf = 0.3 us */
282 } else {
283 dev_err(pd->dev, "unrecognized bus speed %lu Hz\n",
284 pd->bus_speed);
285 return -EINVAL;
286 }
287
288 pd->iccl = sh_mobile_i2c_iccl(i2c_clk_khz, tLOW, tf);
289 pd->icch = sh_mobile_i2c_icch(i2c_clk_khz, tHIGH, tf);
290
291 return sh_mobile_i2c_check_timing(pd);
292 }
293
sh_mobile_i2c_v2_init(struct sh_mobile_i2c_data * pd)294 static int sh_mobile_i2c_v2_init(struct sh_mobile_i2c_data *pd)
295 {
296 unsigned long clks_per_cycle;
297
298 /* L = 5, H = 4, L + H = 9 */
299 clks_per_cycle = clk_get_rate(pd->clk) / pd->bus_speed;
300 pd->iccl = DIV_ROUND_UP(clks_per_cycle * 5 / 9 - 1, pd->clks_per_count);
301 pd->icch = DIV_ROUND_UP(clks_per_cycle * 4 / 9 - 5, pd->clks_per_count);
302
303 return sh_mobile_i2c_check_timing(pd);
304 }
305
i2c_op(struct sh_mobile_i2c_data * pd,enum sh_mobile_i2c_op op,unsigned char data)306 static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
307 enum sh_mobile_i2c_op op, unsigned char data)
308 {
309 unsigned char ret = 0;
310 unsigned long flags;
311
312 dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
313
314 spin_lock_irqsave(&pd->lock, flags);
315
316 switch (op) {
317 case OP_START: /* issue start and trigger DTE interrupt */
318 iic_wr(pd, ICCR, ICCR_ICE | ICCR_TRS | ICCR_BBSY);
319 break;
320 case OP_TX_FIRST: /* disable DTE interrupt and write data */
321 iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
322 iic_wr(pd, ICDR, data);
323 break;
324 case OP_TX: /* write data */
325 iic_wr(pd, ICDR, data);
326 break;
327 case OP_TX_STOP: /* issue a stop (or rep_start) */
328 iic_wr(pd, ICCR, pd->send_stop ? ICCR_ICE | ICCR_TRS
329 : ICCR_ICE | ICCR_TRS | ICCR_BBSY);
330 break;
331 case OP_TX_TO_RX: /* select read mode */
332 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP);
333 break;
334 case OP_RX: /* just read data */
335 ret = iic_rd(pd, ICDR);
336 break;
337 case OP_RX_STOP: /* enable DTE interrupt, issue stop */
338 iic_wr(pd, ICIC,
339 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
340 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
341 break;
342 case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
343 iic_wr(pd, ICIC,
344 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
345 ret = iic_rd(pd, ICDR);
346 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
347 break;
348 }
349
350 spin_unlock_irqrestore(&pd->lock, flags);
351
352 dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
353 return ret;
354 }
355
sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data * pd)356 static bool sh_mobile_i2c_is_first_byte(struct sh_mobile_i2c_data *pd)
357 {
358 return pd->pos == -1;
359 }
360
sh_mobile_i2c_get_data(struct sh_mobile_i2c_data * pd,unsigned char * buf)361 static void sh_mobile_i2c_get_data(struct sh_mobile_i2c_data *pd,
362 unsigned char *buf)
363 {
364 switch (pd->pos) {
365 case -1:
366 *buf = i2c_8bit_addr_from_msg(pd->msg);
367 break;
368 default:
369 *buf = pd->msg->buf[pd->pos];
370 }
371 }
372
sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data * pd)373 static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
374 {
375 unsigned char data;
376
377 if (pd->pos == pd->msg->len) {
378 i2c_op(pd, OP_TX_STOP, 0);
379 return 1;
380 }
381
382 sh_mobile_i2c_get_data(pd, &data);
383 i2c_op(pd, sh_mobile_i2c_is_first_byte(pd) ? OP_TX_FIRST : OP_TX, data);
384
385 pd->pos++;
386 return 0;
387 }
388
sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data * pd)389 static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
390 {
391 unsigned char data;
392 int real_pos;
393
394 do {
395 if (pd->pos <= -1) {
396 sh_mobile_i2c_get_data(pd, &data);
397
398 if (sh_mobile_i2c_is_first_byte(pd))
399 i2c_op(pd, OP_TX_FIRST, data);
400 else
401 i2c_op(pd, OP_TX, data);
402 break;
403 }
404
405 if (pd->pos == 0) {
406 i2c_op(pd, OP_TX_TO_RX, 0);
407 break;
408 }
409
410 real_pos = pd->pos - 2;
411
412 if (pd->pos == pd->msg->len) {
413 if (pd->stop_after_dma) {
414 /* Simulate PIO end condition after DMA transfer */
415 i2c_op(pd, OP_RX_STOP, 0);
416 pd->pos++;
417 break;
418 }
419
420 if (real_pos < 0) {
421 i2c_op(pd, OP_RX_STOP, 0);
422 break;
423 }
424 data = i2c_op(pd, OP_RX_STOP_DATA, 0);
425 } else if (real_pos >= 0) {
426 data = i2c_op(pd, OP_RX, 0);
427 }
428
429 if (real_pos >= 0)
430 pd->msg->buf[real_pos] = data;
431 } while (0);
432
433 pd->pos++;
434 return pd->pos == (pd->msg->len + 2);
435 }
436
sh_mobile_i2c_isr(int irq,void * dev_id)437 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
438 {
439 struct sh_mobile_i2c_data *pd = dev_id;
440 unsigned char sr;
441 int wakeup = 0;
442
443 sr = iic_rd(pd, ICSR);
444 pd->sr |= sr; /* remember state */
445
446 dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
447 (pd->msg->flags & I2C_M_RD) ? "read" : "write",
448 pd->pos, pd->msg->len);
449
450 /* Kick off TxDMA after preface was done */
451 if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0)
452 iic_set_clr(pd, ICIC, ICIC_TDMAE, 0);
453 else if (sr & (ICSR_AL | ICSR_TACK))
454 /* don't interrupt transaction - continue to issue stop */
455 iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK));
456 else if (pd->msg->flags & I2C_M_RD)
457 wakeup = sh_mobile_i2c_isr_rx(pd);
458 else
459 wakeup = sh_mobile_i2c_isr_tx(pd);
460
461 /* Kick off RxDMA after preface was done */
462 if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1)
463 iic_set_clr(pd, ICIC, ICIC_RDMAE, 0);
464
465 if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
466 iic_wr(pd, ICSR, sr & ~ICSR_WAIT);
467
468 if (wakeup) {
469 pd->sr |= SW_DONE;
470 wake_up(&pd->wait);
471 }
472
473 /* defeat write posting to avoid spurious WAIT interrupts */
474 iic_rd(pd, ICSR);
475
476 return IRQ_HANDLED;
477 }
478
sh_mobile_i2c_dma_unmap(struct sh_mobile_i2c_data * pd)479 static void sh_mobile_i2c_dma_unmap(struct sh_mobile_i2c_data *pd)
480 {
481 struct dma_chan *chan = pd->dma_direction == DMA_FROM_DEVICE
482 ? pd->dma_rx : pd->dma_tx;
483
484 dma_unmap_single(chan->device->dev, sg_dma_address(&pd->sg),
485 pd->msg->len, pd->dma_direction);
486
487 pd->dma_direction = DMA_NONE;
488 }
489
sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data * pd)490 static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd)
491 {
492 if (pd->dma_direction == DMA_NONE)
493 return;
494 else if (pd->dma_direction == DMA_FROM_DEVICE)
495 dmaengine_terminate_all(pd->dma_rx);
496 else if (pd->dma_direction == DMA_TO_DEVICE)
497 dmaengine_terminate_all(pd->dma_tx);
498
499 sh_mobile_i2c_dma_unmap(pd);
500 }
501
sh_mobile_i2c_dma_callback(void * data)502 static void sh_mobile_i2c_dma_callback(void *data)
503 {
504 struct sh_mobile_i2c_data *pd = data;
505
506 sh_mobile_i2c_dma_unmap(pd);
507 pd->pos = pd->msg->len;
508 pd->stop_after_dma = true;
509
510 iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE);
511 }
512
sh_mobile_i2c_request_dma_chan(struct device * dev,enum dma_transfer_direction dir,dma_addr_t port_addr)513 static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev,
514 enum dma_transfer_direction dir, dma_addr_t port_addr)
515 {
516 struct dma_chan *chan;
517 struct dma_slave_config cfg;
518 char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
519 int ret;
520
521 chan = dma_request_slave_channel_reason(dev, chan_name);
522 if (IS_ERR(chan)) {
523 dev_dbg(dev, "request_channel failed for %s (%ld)\n", chan_name,
524 PTR_ERR(chan));
525 return chan;
526 }
527
528 memset(&cfg, 0, sizeof(cfg));
529 cfg.direction = dir;
530 if (dir == DMA_MEM_TO_DEV) {
531 cfg.dst_addr = port_addr;
532 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
533 } else {
534 cfg.src_addr = port_addr;
535 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
536 }
537
538 ret = dmaengine_slave_config(chan, &cfg);
539 if (ret) {
540 dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret);
541 dma_release_channel(chan);
542 return ERR_PTR(ret);
543 }
544
545 dev_dbg(dev, "got DMA channel for %s\n", chan_name);
546 return chan;
547 }
548
sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data * pd)549 static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
550 {
551 bool read = pd->msg->flags & I2C_M_RD;
552 enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
553 struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx;
554 struct dma_async_tx_descriptor *txdesc;
555 dma_addr_t dma_addr;
556 dma_cookie_t cookie;
557
558 if (PTR_ERR(chan) == -EPROBE_DEFER) {
559 if (read)
560 chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM,
561 pd->res->start + ICDR);
562 else
563 chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV,
564 pd->res->start + ICDR);
565 }
566
567 if (IS_ERR(chan))
568 return;
569
570 dma_addr = dma_map_single(chan->device->dev, pd->dma_buf, pd->msg->len, dir);
571 if (dma_mapping_error(chan->device->dev, dma_addr)) {
572 dev_dbg(pd->dev, "dma map failed, using PIO\n");
573 return;
574 }
575
576 sg_dma_len(&pd->sg) = pd->msg->len;
577 sg_dma_address(&pd->sg) = dma_addr;
578
579 pd->dma_direction = dir;
580
581 txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1,
582 read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
583 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
584 if (!txdesc) {
585 dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n");
586 sh_mobile_i2c_cleanup_dma(pd);
587 return;
588 }
589
590 txdesc->callback = sh_mobile_i2c_dma_callback;
591 txdesc->callback_param = pd;
592
593 cookie = dmaengine_submit(txdesc);
594 if (dma_submit_error(cookie)) {
595 dev_dbg(pd->dev, "submitting dma failed, using PIO\n");
596 sh_mobile_i2c_cleanup_dma(pd);
597 return;
598 }
599
600 dma_async_issue_pending(chan);
601 }
602
start_ch(struct sh_mobile_i2c_data * pd,struct i2c_msg * usr_msg,bool do_init)603 static void start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
604 bool do_init)
605 {
606 if (do_init) {
607 /* Initialize channel registers */
608 iic_wr(pd, ICCR, ICCR_SCP);
609
610 /* Enable channel and configure rx ack */
611 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP);
612
613 /* Set the clock */
614 iic_wr(pd, ICCL, pd->iccl & 0xff);
615 iic_wr(pd, ICCH, pd->icch & 0xff);
616 }
617
618 pd->msg = usr_msg;
619 pd->pos = -1;
620 pd->sr = 0;
621
622 pd->dma_buf = i2c_get_dma_safe_msg_buf(pd->msg, 8);
623 if (pd->dma_buf)
624 sh_mobile_i2c_xfer_dma(pd);
625
626 /* Enable all interrupts to begin with */
627 iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
628 }
629
poll_dte(struct sh_mobile_i2c_data * pd)630 static int poll_dte(struct sh_mobile_i2c_data *pd)
631 {
632 int i;
633
634 for (i = 1000; i; i--) {
635 u_int8_t val = iic_rd(pd, ICSR);
636
637 if (val & ICSR_DTE)
638 break;
639
640 if (val & ICSR_TACK)
641 return -ENXIO;
642
643 udelay(10);
644 }
645
646 return i ? 0 : -ETIMEDOUT;
647 }
648
poll_busy(struct sh_mobile_i2c_data * pd)649 static int poll_busy(struct sh_mobile_i2c_data *pd)
650 {
651 int i;
652
653 for (i = 1000; i; i--) {
654 u_int8_t val = iic_rd(pd, ICSR);
655
656 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
657
658 /* the interrupt handler may wake us up before the
659 * transfer is finished, so poll the hardware
660 * until we're done.
661 */
662 if (!(val & ICSR_BUSY)) {
663 /* handle missing acknowledge and arbitration lost */
664 val |= pd->sr;
665 if (val & ICSR_TACK)
666 return -ENXIO;
667 if (val & ICSR_AL)
668 return -EAGAIN;
669 break;
670 }
671
672 udelay(10);
673 }
674
675 return i ? 0 : -ETIMEDOUT;
676 }
677
sh_mobile_i2c_xfer(struct i2c_adapter * adapter,struct i2c_msg * msgs,int num)678 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
679 struct i2c_msg *msgs,
680 int num)
681 {
682 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
683 struct i2c_msg *msg;
684 int err = 0;
685 int i;
686 long timeout;
687
688 /* Wake up device and enable clock */
689 pm_runtime_get_sync(pd->dev);
690
691 /* Process all messages */
692 for (i = 0; i < num; i++) {
693 bool do_start = pd->send_stop || !i;
694 msg = &msgs[i];
695 pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP;
696 pd->stop_after_dma = false;
697
698 start_ch(pd, msg, do_start);
699
700 if (do_start)
701 i2c_op(pd, OP_START, 0);
702
703 /* The interrupt handler takes care of the rest... */
704 timeout = wait_event_timeout(pd->wait,
705 pd->sr & (ICSR_TACK | SW_DONE),
706 adapter->timeout);
707
708 /* 'stop_after_dma' tells if DMA transfer was complete */
709 i2c_put_dma_safe_msg_buf(pd->dma_buf, pd->msg, pd->stop_after_dma);
710
711 if (!timeout) {
712 dev_err(pd->dev, "Transfer request timed out\n");
713 if (pd->dma_direction != DMA_NONE)
714 sh_mobile_i2c_cleanup_dma(pd);
715
716 err = -ETIMEDOUT;
717 break;
718 }
719
720 if (pd->send_stop)
721 err = poll_busy(pd);
722 else
723 err = poll_dte(pd);
724 if (err < 0)
725 break;
726 }
727
728 /* Disable channel */
729 iic_wr(pd, ICCR, ICCR_SCP);
730
731 /* Disable clock and mark device as idle */
732 pm_runtime_put_sync(pd->dev);
733
734 return err ?: num;
735 }
736
sh_mobile_i2c_func(struct i2c_adapter * adapter)737 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
738 {
739 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
740 }
741
742 static const struct i2c_algorithm sh_mobile_i2c_algorithm = {
743 .functionality = sh_mobile_i2c_func,
744 .master_xfer = sh_mobile_i2c_xfer,
745 };
746
747 static const struct i2c_adapter_quirks sh_mobile_i2c_quirks = {
748 .flags = I2C_AQ_NO_ZERO_LEN_READ,
749 };
750
751 /*
752 * r8a7740 chip has lasting errata on I2C I/O pad reset.
753 * this is work-around for it.
754 */
sh_mobile_i2c_r8a7740_workaround(struct sh_mobile_i2c_data * pd)755 static int sh_mobile_i2c_r8a7740_workaround(struct sh_mobile_i2c_data *pd)
756 {
757 iic_set_clr(pd, ICCR, ICCR_ICE, 0);
758 iic_rd(pd, ICCR); /* dummy read */
759
760 iic_set_clr(pd, ICSTART, ICSTART_ICSTART, 0);
761 iic_rd(pd, ICSTART); /* dummy read */
762
763 udelay(10);
764
765 iic_wr(pd, ICCR, ICCR_SCP);
766 iic_wr(pd, ICSTART, 0);
767
768 udelay(10);
769
770 iic_wr(pd, ICCR, ICCR_TRS);
771 udelay(10);
772 iic_wr(pd, ICCR, 0);
773 udelay(10);
774 iic_wr(pd, ICCR, ICCR_TRS);
775 udelay(10);
776
777 return sh_mobile_i2c_init(pd);
778 }
779
780 static const struct sh_mobile_dt_config default_dt_config = {
781 .clks_per_count = 1,
782 .setup = sh_mobile_i2c_init,
783 };
784
785 static const struct sh_mobile_dt_config fast_clock_dt_config = {
786 .clks_per_count = 2,
787 .setup = sh_mobile_i2c_init,
788 };
789
790 static const struct sh_mobile_dt_config v2_freq_calc_dt_config = {
791 .clks_per_count = 2,
792 .setup = sh_mobile_i2c_v2_init,
793 };
794
795 static const struct sh_mobile_dt_config r8a7740_dt_config = {
796 .clks_per_count = 1,
797 .setup = sh_mobile_i2c_r8a7740_workaround,
798 };
799
800 static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
801 { .compatible = "renesas,iic-r8a73a4", .data = &fast_clock_dt_config },
802 { .compatible = "renesas,iic-r8a7740", .data = &r8a7740_dt_config },
803 { .compatible = "renesas,iic-r8a7790", .data = &v2_freq_calc_dt_config },
804 { .compatible = "renesas,iic-r8a7791", .data = &fast_clock_dt_config },
805 { .compatible = "renesas,iic-r8a7792", .data = &fast_clock_dt_config },
806 { .compatible = "renesas,iic-r8a7793", .data = &fast_clock_dt_config },
807 { .compatible = "renesas,iic-r8a7794", .data = &fast_clock_dt_config },
808 { .compatible = "renesas,rcar-gen2-iic", .data = &fast_clock_dt_config },
809 { .compatible = "renesas,iic-r8a7795", .data = &fast_clock_dt_config },
810 { .compatible = "renesas,rcar-gen3-iic", .data = &fast_clock_dt_config },
811 { .compatible = "renesas,iic-sh73a0", .data = &fast_clock_dt_config },
812 { .compatible = "renesas,rmobile-iic", .data = &default_dt_config },
813 {},
814 };
815 MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids);
816
sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data * pd)817 static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd)
818 {
819 if (!IS_ERR(pd->dma_tx)) {
820 dma_release_channel(pd->dma_tx);
821 pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
822 }
823
824 if (!IS_ERR(pd->dma_rx)) {
825 dma_release_channel(pd->dma_rx);
826 pd->dma_rx = ERR_PTR(-EPROBE_DEFER);
827 }
828 }
829
sh_mobile_i2c_hook_irqs(struct platform_device * dev,struct sh_mobile_i2c_data * pd)830 static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, struct sh_mobile_i2c_data *pd)
831 {
832 struct resource *res;
833 resource_size_t n;
834 int k = 0, ret;
835
836 while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
837 for (n = res->start; n <= res->end; n++) {
838 ret = devm_request_irq(&dev->dev, n, sh_mobile_i2c_isr,
839 0, dev_name(&dev->dev), pd);
840 if (ret) {
841 dev_err(&dev->dev, "cannot request IRQ %pa\n", &n);
842 return ret;
843 }
844 }
845 k++;
846 }
847
848 return k > 0 ? 0 : -ENOENT;
849 }
850
sh_mobile_i2c_probe(struct platform_device * dev)851 static int sh_mobile_i2c_probe(struct platform_device *dev)
852 {
853 struct sh_mobile_i2c_data *pd;
854 struct i2c_adapter *adap;
855 struct resource *res;
856 const struct sh_mobile_dt_config *config;
857 int ret;
858 u32 bus_speed;
859
860 pd = devm_kzalloc(&dev->dev, sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
861 if (!pd)
862 return -ENOMEM;
863
864 pd->clk = devm_clk_get(&dev->dev, NULL);
865 if (IS_ERR(pd->clk)) {
866 dev_err(&dev->dev, "cannot get clock\n");
867 return PTR_ERR(pd->clk);
868 }
869
870 ret = sh_mobile_i2c_hook_irqs(dev, pd);
871 if (ret)
872 return ret;
873
874 pd->dev = &dev->dev;
875 platform_set_drvdata(dev, pd);
876
877 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
878
879 pd->res = res;
880 pd->reg = devm_ioremap_resource(&dev->dev, res);
881 if (IS_ERR(pd->reg))
882 return PTR_ERR(pd->reg);
883
884 ret = of_property_read_u32(dev->dev.of_node, "clock-frequency", &bus_speed);
885 pd->bus_speed = (ret || !bus_speed) ? STANDARD_MODE : bus_speed;
886 pd->clks_per_count = 1;
887
888 /* Newer variants come with two new bits in ICIC */
889 if (resource_size(res) > 0x17)
890 pd->flags |= IIC_FLAG_HAS_ICIC67;
891
892 pm_runtime_enable(&dev->dev);
893 pm_runtime_get_sync(&dev->dev);
894
895 config = of_device_get_match_data(&dev->dev);
896 if (config) {
897 pd->clks_per_count = config->clks_per_count;
898 ret = config->setup(pd);
899 } else {
900 ret = sh_mobile_i2c_init(pd);
901 }
902
903 pm_runtime_put_sync(&dev->dev);
904 if (ret)
905 return ret;
906
907 /* Init DMA */
908 sg_init_table(&pd->sg, 1);
909 pd->dma_direction = DMA_NONE;
910 pd->dma_rx = pd->dma_tx = ERR_PTR(-EPROBE_DEFER);
911
912 /* setup the private data */
913 adap = &pd->adap;
914 i2c_set_adapdata(adap, pd);
915
916 adap->owner = THIS_MODULE;
917 adap->algo = &sh_mobile_i2c_algorithm;
918 adap->quirks = &sh_mobile_i2c_quirks;
919 adap->dev.parent = &dev->dev;
920 adap->retries = 5;
921 adap->nr = dev->id;
922 adap->dev.of_node = dev->dev.of_node;
923
924 strlcpy(adap->name, dev->name, sizeof(adap->name));
925
926 spin_lock_init(&pd->lock);
927 init_waitqueue_head(&pd->wait);
928
929 ret = i2c_add_numbered_adapter(adap);
930 if (ret < 0) {
931 sh_mobile_i2c_release_dma(pd);
932 return ret;
933 }
934
935 dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed);
936
937 return 0;
938 }
939
sh_mobile_i2c_remove(struct platform_device * dev)940 static int sh_mobile_i2c_remove(struct platform_device *dev)
941 {
942 struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
943
944 i2c_del_adapter(&pd->adap);
945 sh_mobile_i2c_release_dma(pd);
946 pm_runtime_disable(&dev->dev);
947 return 0;
948 }
949
sh_mobile_i2c_runtime_nop(struct device * dev)950 static int sh_mobile_i2c_runtime_nop(struct device *dev)
951 {
952 /* Runtime PM callback shared between ->runtime_suspend()
953 * and ->runtime_resume(). Simply returns success.
954 *
955 * This driver re-initializes all registers after
956 * pm_runtime_get_sync() anyway so there is no need
957 * to save and restore registers here.
958 */
959 return 0;
960 }
961
962 static const struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = {
963 .runtime_suspend = sh_mobile_i2c_runtime_nop,
964 .runtime_resume = sh_mobile_i2c_runtime_nop,
965 };
966
967 static struct platform_driver sh_mobile_i2c_driver = {
968 .driver = {
969 .name = "i2c-sh_mobile",
970 .pm = &sh_mobile_i2c_dev_pm_ops,
971 .of_match_table = sh_mobile_i2c_dt_ids,
972 },
973 .probe = sh_mobile_i2c_probe,
974 .remove = sh_mobile_i2c_remove,
975 };
976
sh_mobile_i2c_adap_init(void)977 static int __init sh_mobile_i2c_adap_init(void)
978 {
979 return platform_driver_register(&sh_mobile_i2c_driver);
980 }
981 subsys_initcall(sh_mobile_i2c_adap_init);
982
sh_mobile_i2c_adap_exit(void)983 static void __exit sh_mobile_i2c_adap_exit(void)
984 {
985 platform_driver_unregister(&sh_mobile_i2c_driver);
986 }
987 module_exit(sh_mobile_i2c_adap_exit);
988
989 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
990 MODULE_AUTHOR("Magnus Damm and Wolfram Sang");
991 MODULE_LICENSE("GPL v2");
992 MODULE_ALIAS("platform:i2c-sh_mobile");
993
