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.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
102enum 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
113struct 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 bool atomic_xfer;
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
142struct 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/* Register offsets */
150#define ICDR 0x00
151#define ICCR 0x04
152#define ICSR 0x08
153#define ICIC 0x0c
154#define ICCL 0x10
155#define ICCH 0x14
156#define ICSTART 0x70
157
158/* Register bits */
159#define ICCR_ICE 0x80
160#define ICCR_RACK 0x40
161#define ICCR_TRS 0x10
162#define ICCR_BBSY 0x04
163#define ICCR_SCP 0x01
164
165#define ICSR_SCLM 0x80
166#define ICSR_SDAM 0x40
167#define SW_DONE 0x20
168#define ICSR_BUSY 0x10
169#define ICSR_AL 0x08
170#define ICSR_TACK 0x04
171#define ICSR_WAIT 0x02
172#define ICSR_DTE 0x01
173
174#define ICIC_ICCLB8 0x80
175#define ICIC_ICCHB8 0x40
176#define ICIC_TDMAE 0x20
177#define ICIC_RDMAE 0x10
178#define ICIC_ALE 0x08
179#define ICIC_TACKE 0x04
180#define ICIC_WAITE 0x02
181#define ICIC_DTEE 0x01
182
183#define ICSTART_ICSTART 0x10
184
185static void iic_wr(struct sh_mobile_i2c_data *pd, int offs, unsigned char data)
186{
187 if (offs == ICIC)
188 data |= pd->icic;
189
190 iowrite8(data, pd->reg + offs);
191}
192
193static unsigned char iic_rd(struct sh_mobile_i2c_data *pd, int offs)
194{
195 return ioread8(pd->reg + offs);
196}
197
198static void iic_set_clr(struct sh_mobile_i2c_data *pd, int offs,
199 unsigned char set, unsigned char clr)
200{
201 iic_wr(pd, offs, data: (iic_rd(pd, offs) | set) & ~clr);
202}
203
204static u32 sh_mobile_i2c_iccl(unsigned long count_khz, u32 tLOW, u32 tf)
205{
206 /*
207 * Conditional expression:
208 * ICCL >= COUNT_CLK * (tLOW + tf)
209 *
210 * SH-Mobile IIC hardware starts counting the LOW period of
211 * the SCL signal (tLOW) as soon as it pulls the SCL line.
212 * In order to meet the tLOW timing spec, we need to take into
213 * account the fall time of SCL signal (tf). Default tf value
214 * should be 0.3 us, for safety.
215 */
216 return (((count_khz * (tLOW + tf)) + 5000) / 10000);
217}
218
219static u32 sh_mobile_i2c_icch(unsigned long count_khz, u32 tHIGH, u32 tf)
220{
221 /*
222 * Conditional expression:
223 * ICCH >= COUNT_CLK * (tHIGH + tf)
224 *
225 * SH-Mobile IIC hardware is aware of SCL transition period 'tr',
226 * and can ignore it. SH-Mobile IIC controller starts counting
227 * the HIGH period of the SCL signal (tHIGH) after the SCL input
228 * voltage increases at VIH.
229 *
230 * Afterward it turned out calculating ICCH using only tHIGH spec
231 * will result in violation of the tHD;STA timing spec. We need
232 * to take into account the fall time of SDA signal (tf) at START
233 * condition, in order to meet both tHIGH and tHD;STA specs.
234 */
235 return (((count_khz * (tHIGH + tf)) + 5000) / 10000);
236}
237
238static int sh_mobile_i2c_check_timing(struct sh_mobile_i2c_data *pd)
239{
240 u16 max_val = pd->flags & IIC_FLAG_HAS_ICIC67 ? 0x1ff : 0xff;
241
242 if (pd->iccl > max_val || pd->icch > max_val) {
243 dev_err(pd->dev, "timing values out of range: L/H=0x%x/0x%x\n",
244 pd->iccl, pd->icch);
245 return -EINVAL;
246 }
247
248 /* one more bit of ICCL in ICIC */
249 if (pd->iccl & 0x100)
250 pd->icic |= ICIC_ICCLB8;
251 else
252 pd->icic &= ~ICIC_ICCLB8;
253
254 /* one more bit of ICCH in ICIC */
255 if (pd->icch & 0x100)
256 pd->icic |= ICIC_ICCHB8;
257 else
258 pd->icic &= ~ICIC_ICCHB8;
259
260 dev_dbg(pd->dev, "timing values: L/H=0x%x/0x%x\n", pd->iccl, pd->icch);
261 return 0;
262}
263
264static int sh_mobile_i2c_init(struct sh_mobile_i2c_data *pd)
265{
266 unsigned long i2c_clk_khz;
267 u32 tHIGH, tLOW, tf;
268
269 i2c_clk_khz = clk_get_rate(clk: pd->clk) / 1000 / pd->clks_per_count;
270
271 if (pd->bus_speed == I2C_MAX_STANDARD_MODE_FREQ) {
272 tLOW = 47; /* tLOW = 4.7 us */
273 tHIGH = 40; /* tHD;STA = tHIGH = 4.0 us */
274 tf = 3; /* tf = 0.3 us */
275 } else if (pd->bus_speed == I2C_MAX_FAST_MODE_FREQ) {
276 tLOW = 13; /* tLOW = 1.3 us */
277 tHIGH = 6; /* tHD;STA = tHIGH = 0.6 us */
278 tf = 3; /* tf = 0.3 us */
279 } else {
280 dev_err(pd->dev, "unrecognized bus speed %lu Hz\n",
281 pd->bus_speed);
282 return -EINVAL;
283 }
284
285 pd->iccl = sh_mobile_i2c_iccl(count_khz: i2c_clk_khz, tLOW, tf);
286 pd->icch = sh_mobile_i2c_icch(count_khz: i2c_clk_khz, tHIGH, tf);
287
288 return sh_mobile_i2c_check_timing(pd);
289}
290
291static int sh_mobile_i2c_v2_init(struct sh_mobile_i2c_data *pd)
292{
293 unsigned long clks_per_cycle;
294
295 /* L = 5, H = 4, L + H = 9 */
296 clks_per_cycle = clk_get_rate(clk: pd->clk) / pd->bus_speed;
297 pd->iccl = DIV_ROUND_UP(clks_per_cycle * 5 / 9 - 1, pd->clks_per_count);
298 pd->icch = DIV_ROUND_UP(clks_per_cycle * 4 / 9 - 5, pd->clks_per_count);
299
300 return sh_mobile_i2c_check_timing(pd);
301}
302
303static unsigned char i2c_op(struct sh_mobile_i2c_data *pd, enum sh_mobile_i2c_op op)
304{
305 unsigned char ret = 0;
306 unsigned long flags;
307
308 dev_dbg(pd->dev, "op %d\n", op);
309
310 spin_lock_irqsave(&pd->lock, flags);
311
312 switch (op) {
313 case OP_START: /* issue start and trigger DTE interrupt */
314 iic_wr(pd, ICCR, ICCR_ICE | ICCR_TRS | ICCR_BBSY);
315 break;
316 case OP_TX_FIRST: /* disable DTE interrupt and write client address */
317 iic_wr(pd, ICIC, ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
318 iic_wr(pd, ICDR, data: i2c_8bit_addr_from_msg(msg: pd->msg));
319 break;
320 case OP_TX: /* write data */
321 iic_wr(pd, ICDR, data: pd->msg->buf[pd->pos]);
322 break;
323 case OP_TX_STOP: /* issue a stop (or rep_start) */
324 iic_wr(pd, ICCR, data: pd->send_stop ? ICCR_ICE | ICCR_TRS
325 : ICCR_ICE | ICCR_TRS | ICCR_BBSY);
326 break;
327 case OP_TX_TO_RX: /* select read mode */
328 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP);
329 break;
330 case OP_RX: /* just read data */
331 ret = iic_rd(pd, ICDR);
332 break;
333 case OP_RX_STOP: /* enable DTE interrupt, issue stop */
334 if (!pd->atomic_xfer)
335 iic_wr(pd, ICIC,
336 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
337 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
338 break;
339 case OP_RX_STOP_DATA: /* enable DTE interrupt, read data, issue stop */
340 if (!pd->atomic_xfer)
341 iic_wr(pd, ICIC,
342 ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
343 ret = iic_rd(pd, ICDR);
344 iic_wr(pd, ICCR, ICCR_ICE | ICCR_RACK);
345 break;
346 }
347
348 spin_unlock_irqrestore(lock: &pd->lock, flags);
349
350 dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
351 return ret;
352}
353
354static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
355{
356 if (pd->pos == pd->msg->len) {
357 i2c_op(pd, op: OP_TX_STOP);
358 return 1;
359 }
360
361 if (pd->pos == -1)
362 i2c_op(pd, op: OP_TX_FIRST);
363 else
364 i2c_op(pd, op: OP_TX);
365
366 pd->pos++;
367 return 0;
368}
369
370static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
371{
372 int real_pos;
373
374 /* switch from TX (address) to RX (data) adds two interrupts */
375 real_pos = pd->pos - 2;
376
377 if (pd->pos == -1) {
378 i2c_op(pd, op: OP_TX_FIRST);
379 } else if (pd->pos == 0) {
380 i2c_op(pd, op: OP_TX_TO_RX);
381 } else if (pd->pos == pd->msg->len) {
382 if (pd->stop_after_dma) {
383 /* Simulate PIO end condition after DMA transfer */
384 i2c_op(pd, op: OP_RX_STOP);
385 pd->pos++;
386 goto done;
387 }
388
389 if (real_pos < 0)
390 i2c_op(pd, op: OP_RX_STOP);
391 else
392 pd->msg->buf[real_pos] = i2c_op(pd, op: OP_RX_STOP_DATA);
393 } else if (real_pos >= 0) {
394 pd->msg->buf[real_pos] = i2c_op(pd, op: OP_RX);
395 }
396
397 done:
398 pd->pos++;
399 return pd->pos == (pd->msg->len + 2);
400}
401
402static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
403{
404 struct sh_mobile_i2c_data *pd = dev_id;
405 unsigned char sr;
406 int wakeup = 0;
407
408 sr = iic_rd(pd, ICSR);
409 pd->sr |= sr; /* remember state */
410
411 dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
412 (pd->msg->flags & I2C_M_RD) ? "read" : "write",
413 pd->pos, pd->msg->len);
414
415 /* Kick off TxDMA after preface was done */
416 if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0)
417 iic_set_clr(pd, ICIC, ICIC_TDMAE, clr: 0);
418 else if (sr & (ICSR_AL | ICSR_TACK))
419 /* don't interrupt transaction - continue to issue stop */
420 iic_wr(pd, ICSR, data: sr & ~(ICSR_AL | ICSR_TACK));
421 else if (pd->msg->flags & I2C_M_RD)
422 wakeup = sh_mobile_i2c_isr_rx(pd);
423 else
424 wakeup = sh_mobile_i2c_isr_tx(pd);
425
426 /* Kick off RxDMA after preface was done */
427 if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1)
428 iic_set_clr(pd, ICIC, ICIC_RDMAE, clr: 0);
429
430 if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
431 iic_wr(pd, ICSR, data: sr & ~ICSR_WAIT);
432
433 if (wakeup) {
434 pd->sr |= SW_DONE;
435 if (!pd->atomic_xfer)
436 wake_up(&pd->wait);
437 }
438
439 /* defeat write posting to avoid spurious WAIT interrupts */
440 iic_rd(pd, ICSR);
441
442 return IRQ_HANDLED;
443}
444
445static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd, bool terminate)
446{
447 struct dma_chan *chan = pd->dma_direction == DMA_FROM_DEVICE
448 ? pd->dma_rx : pd->dma_tx;
449
450 /* only allowed from thread context! */
451 if (terminate)
452 dmaengine_terminate_sync(chan);
453
454 dma_unmap_single(chan->device->dev, sg_dma_address(&pd->sg),
455 pd->msg->len, pd->dma_direction);
456
457 pd->dma_direction = DMA_NONE;
458}
459
460static void sh_mobile_i2c_dma_callback(void *data)
461{
462 struct sh_mobile_i2c_data *pd = data;
463
464 sh_mobile_i2c_cleanup_dma(pd, terminate: false);
465 pd->pos = pd->msg->len;
466 pd->stop_after_dma = true;
467
468 iic_set_clr(pd, ICIC, set: 0, ICIC_TDMAE | ICIC_RDMAE);
469}
470
471static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev,
472 enum dma_transfer_direction dir, dma_addr_t port_addr)
473{
474 struct dma_chan *chan;
475 struct dma_slave_config cfg;
476 char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
477 int ret;
478
479 chan = dma_request_chan(dev, name: chan_name);
480 if (IS_ERR(ptr: chan)) {
481 dev_dbg(dev, "request_channel failed for %s (%ld)\n", chan_name,
482 PTR_ERR(chan));
483 return chan;
484 }
485
486 memset(&cfg, 0, sizeof(cfg));
487 cfg.direction = dir;
488 if (dir == DMA_MEM_TO_DEV) {
489 cfg.dst_addr = port_addr;
490 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
491 } else {
492 cfg.src_addr = port_addr;
493 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
494 }
495
496 ret = dmaengine_slave_config(chan, config: &cfg);
497 if (ret) {
498 dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret);
499 dma_release_channel(chan);
500 return ERR_PTR(error: ret);
501 }
502
503 dev_dbg(dev, "got DMA channel for %s\n", chan_name);
504 return chan;
505}
506
507static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
508{
509 bool read = pd->msg->flags & I2C_M_RD;
510 enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
511 struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx;
512 struct dma_async_tx_descriptor *txdesc;
513 dma_addr_t dma_addr;
514 dma_cookie_t cookie;
515
516 if (PTR_ERR(ptr: chan) == -EPROBE_DEFER) {
517 if (read)
518 chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(dev: pd->dev, dir: DMA_DEV_TO_MEM,
519 port_addr: pd->res->start + ICDR);
520 else
521 chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(dev: pd->dev, dir: DMA_MEM_TO_DEV,
522 port_addr: pd->res->start + ICDR);
523 }
524
525 if (IS_ERR(ptr: chan))
526 return;
527
528 dma_addr = dma_map_single(chan->device->dev, pd->dma_buf, pd->msg->len, dir);
529 if (dma_mapping_error(dev: chan->device->dev, dma_addr)) {
530 dev_dbg(pd->dev, "dma map failed, using PIO\n");
531 return;
532 }
533
534 sg_dma_len(&pd->sg) = pd->msg->len;
535 sg_dma_address(&pd->sg) = dma_addr;
536
537 pd->dma_direction = dir;
538
539 txdesc = dmaengine_prep_slave_sg(chan, sgl: &pd->sg, sg_len: 1,
540 dir: read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
541 flags: DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
542 if (!txdesc) {
543 dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n");
544 sh_mobile_i2c_cleanup_dma(pd, terminate: false);
545 return;
546 }
547
548 txdesc->callback = sh_mobile_i2c_dma_callback;
549 txdesc->callback_param = pd;
550
551 cookie = dmaengine_submit(desc: txdesc);
552 if (dma_submit_error(cookie)) {
553 dev_dbg(pd->dev, "submitting dma failed, using PIO\n");
554 sh_mobile_i2c_cleanup_dma(pd, terminate: false);
555 return;
556 }
557
558 dma_async_issue_pending(chan);
559}
560
561static void start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
562 bool do_init)
563{
564 if (do_init) {
565 /* Initialize channel registers */
566 iic_wr(pd, ICCR, ICCR_SCP);
567
568 /* Enable channel and configure rx ack */
569 iic_wr(pd, ICCR, ICCR_ICE | ICCR_SCP);
570
571 /* Set the clock */
572 iic_wr(pd, ICCL, data: pd->iccl & 0xff);
573 iic_wr(pd, ICCH, data: pd->icch & 0xff);
574 }
575
576 pd->msg = usr_msg;
577 pd->pos = -1;
578 pd->sr = 0;
579
580 if (pd->atomic_xfer)
581 return;
582
583 pd->dma_buf = i2c_get_dma_safe_msg_buf(msg: pd->msg, threshold: 8);
584 if (pd->dma_buf)
585 sh_mobile_i2c_xfer_dma(pd);
586
587 /* Enable all interrupts to begin with */
588 iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
589}
590
591static int poll_dte(struct sh_mobile_i2c_data *pd)
592{
593 int i;
594
595 for (i = 1000; i; i--) {
596 u_int8_t val = iic_rd(pd, ICSR);
597
598 if (val & ICSR_DTE)
599 break;
600
601 if (val & ICSR_TACK)
602 return -ENXIO;
603
604 udelay(10);
605 }
606
607 return i ? 0 : -ETIMEDOUT;
608}
609
610static int poll_busy(struct sh_mobile_i2c_data *pd)
611{
612 int i;
613
614 for (i = 1000; i; i--) {
615 u_int8_t val = iic_rd(pd, ICSR);
616
617 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
618
619 /* the interrupt handler may wake us up before the
620 * transfer is finished, so poll the hardware
621 * until we're done.
622 */
623 if (!(val & ICSR_BUSY)) {
624 /* handle missing acknowledge and arbitration lost */
625 val |= pd->sr;
626 if (val & ICSR_TACK)
627 return -ENXIO;
628 if (val & ICSR_AL)
629 return -EAGAIN;
630 break;
631 }
632
633 udelay(10);
634 }
635
636 return i ? 0 : -ETIMEDOUT;
637}
638
639static int sh_mobile_xfer(struct sh_mobile_i2c_data *pd,
640 struct i2c_msg *msgs, int num)
641{
642 struct i2c_msg *msg;
643 int err = 0;
644 int i;
645 long time_left;
646
647 /* Wake up device and enable clock */
648 pm_runtime_get_sync(dev: pd->dev);
649
650 /* Process all messages */
651 for (i = 0; i < num; i++) {
652 bool do_start = pd->send_stop || !i;
653 msg = &msgs[i];
654 pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP;
655 pd->stop_after_dma = false;
656
657 start_ch(pd, usr_msg: msg, do_init: do_start);
658
659 if (do_start)
660 i2c_op(pd, op: OP_START);
661
662 if (pd->atomic_xfer) {
663 unsigned long j = jiffies + pd->adap.timeout;
664
665 time_left = time_before_eq(jiffies, j);
666 while (time_left &&
667 !(pd->sr & (ICSR_TACK | SW_DONE))) {
668 unsigned char sr = iic_rd(pd, ICSR);
669
670 if (sr & (ICSR_AL | ICSR_TACK |
671 ICSR_WAIT | ICSR_DTE)) {
672 sh_mobile_i2c_isr(irq: 0, dev_id: pd);
673 udelay(150);
674 } else {
675 cpu_relax();
676 }
677 time_left = time_before_eq(jiffies, j);
678 }
679 } else {
680 /* The interrupt handler takes care of the rest... */
681 time_left = wait_event_timeout(pd->wait,
682 pd->sr & (ICSR_TACK | SW_DONE),
683 pd->adap.timeout);
684
685 /* 'stop_after_dma' tells if DMA xfer was complete */
686 i2c_put_dma_safe_msg_buf(buf: pd->dma_buf, msg: pd->msg,
687 xferred: pd->stop_after_dma);
688 }
689
690 if (!time_left) {
691 dev_err(pd->dev, "Transfer request timed out\n");
692 if (pd->dma_direction != DMA_NONE)
693 sh_mobile_i2c_cleanup_dma(pd, terminate: true);
694
695 err = -ETIMEDOUT;
696 break;
697 }
698
699 if (pd->send_stop)
700 err = poll_busy(pd);
701 else
702 err = poll_dte(pd);
703 if (err < 0)
704 break;
705 }
706
707 /* Disable channel */
708 iic_wr(pd, ICCR, ICCR_SCP);
709
710 /* Disable clock and mark device as idle */
711 pm_runtime_put_sync(dev: pd->dev);
712
713 return err ?: num;
714}
715
716static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
717 struct i2c_msg *msgs,
718 int num)
719{
720 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adap: adapter);
721
722 pd->atomic_xfer = false;
723 return sh_mobile_xfer(pd, msgs, num);
724}
725
726static int sh_mobile_i2c_xfer_atomic(struct i2c_adapter *adapter,
727 struct i2c_msg *msgs,
728 int num)
729{
730 struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adap: adapter);
731
732 pd->atomic_xfer = true;
733 return sh_mobile_xfer(pd, msgs, num);
734}
735
736static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
737{
738 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
739}
740
741static const struct i2c_algorithm sh_mobile_i2c_algorithm = {
742 .functionality = sh_mobile_i2c_func,
743 .master_xfer = sh_mobile_i2c_xfer,
744 .master_xfer_atomic = sh_mobile_i2c_xfer_atomic,
745};
746
747static const struct i2c_adapter_quirks sh_mobile_i2c_quirks = {
748 .flags = I2C_AQ_NO_ZERO_LEN_READ,
749};
750
751/*
752 * r8a7740 has an errata regarding I2C I/O pad reset needing this workaround.
753 */
754static int sh_mobile_i2c_r8a7740_workaround(struct sh_mobile_i2c_data *pd)
755{
756 iic_set_clr(pd, ICCR, ICCR_ICE, clr: 0);
757 iic_rd(pd, ICCR); /* dummy read */
758
759 iic_set_clr(pd, ICSTART, ICSTART_ICSTART, clr: 0);
760 iic_rd(pd, ICSTART); /* dummy read */
761
762 udelay(10);
763
764 iic_wr(pd, ICCR, ICCR_SCP);
765 iic_wr(pd, ICSTART, data: 0);
766
767 udelay(10);
768
769 iic_wr(pd, ICCR, ICCR_TRS);
770 udelay(10);
771 iic_wr(pd, ICCR, data: 0);
772 udelay(10);
773 iic_wr(pd, ICCR, ICCR_TRS);
774 udelay(10);
775
776 return sh_mobile_i2c_init(pd);
777}
778
779static const struct sh_mobile_dt_config default_dt_config = {
780 .clks_per_count = 1,
781 .setup = sh_mobile_i2c_init,
782};
783
784static const struct sh_mobile_dt_config fast_clock_dt_config = {
785 .clks_per_count = 2,
786 .setup = sh_mobile_i2c_init,
787};
788
789static const struct sh_mobile_dt_config v2_freq_calc_dt_config = {
790 .clks_per_count = 2,
791 .setup = sh_mobile_i2c_v2_init,
792};
793
794static const struct sh_mobile_dt_config r8a7740_dt_config = {
795 .clks_per_count = 1,
796 .setup = sh_mobile_i2c_r8a7740_workaround,
797};
798
799static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
800 { .compatible = "renesas,iic-r8a73a4", .data = &fast_clock_dt_config },
801 { .compatible = "renesas,iic-r8a7740", .data = &r8a7740_dt_config },
802 { .compatible = "renesas,iic-r8a774c0", .data = &v2_freq_calc_dt_config },
803 { .compatible = "renesas,iic-r8a7790", .data = &v2_freq_calc_dt_config },
804 { .compatible = "renesas,iic-r8a7791", .data = &v2_freq_calc_dt_config },
805 { .compatible = "renesas,iic-r8a7792", .data = &v2_freq_calc_dt_config },
806 { .compatible = "renesas,iic-r8a7793", .data = &v2_freq_calc_dt_config },
807 { .compatible = "renesas,iic-r8a7794", .data = &v2_freq_calc_dt_config },
808 { .compatible = "renesas,iic-r8a7795", .data = &v2_freq_calc_dt_config },
809 { .compatible = "renesas,iic-r8a77990", .data = &v2_freq_calc_dt_config },
810 { .compatible = "renesas,iic-sh73a0", .data = &fast_clock_dt_config },
811 { .compatible = "renesas,rcar-gen2-iic", .data = &v2_freq_calc_dt_config },
812 { .compatible = "renesas,rcar-gen3-iic", .data = &v2_freq_calc_dt_config },
813 { .compatible = "renesas,rmobile-iic", .data = &default_dt_config },
814 {},
815};
816MODULE_DEVICE_TABLE(of, sh_mobile_i2c_dt_ids);
817
818static void sh_mobile_i2c_release_dma(struct sh_mobile_i2c_data *pd)
819{
820 if (!IS_ERR(ptr: pd->dma_tx)) {
821 dma_release_channel(chan: pd->dma_tx);
822 pd->dma_tx = ERR_PTR(error: -EPROBE_DEFER);
823 }
824
825 if (!IS_ERR(ptr: pd->dma_rx)) {
826 dma_release_channel(chan: pd->dma_rx);
827 pd->dma_rx = ERR_PTR(error: -EPROBE_DEFER);
828 }
829}
830
831static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, struct sh_mobile_i2c_data *pd)
832{
833 struct device_node *np = dev_of_node(dev: &dev->dev);
834 int k = 0, ret;
835
836 if (np) {
837 int irq;
838
839 while ((irq = platform_get_irq_optional(dev, k)) != -ENXIO) {
840 if (irq < 0)
841 return irq;
842 ret = devm_request_irq(dev: &dev->dev, irq, handler: sh_mobile_i2c_isr,
843 irqflags: 0, devname: dev_name(dev: &dev->dev), dev_id: pd);
844 if (ret) {
845 dev_err(&dev->dev, "cannot request IRQ %d\n", irq);
846 return ret;
847 }
848 k++;
849 }
850 } else {
851 struct resource *res;
852 resource_size_t n;
853
854 while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
855 for (n = res->start; n <= res->end; n++) {
856 ret = devm_request_irq(dev: &dev->dev, irq: n, handler: sh_mobile_i2c_isr,
857 irqflags: 0, devname: dev_name(dev: &dev->dev), dev_id: pd);
858 if (ret) {
859 dev_err(&dev->dev, "cannot request IRQ %pa\n", &n);
860 return ret;
861 }
862 }
863 k++;
864 }
865 }
866
867 return k > 0 ? 0 : -ENOENT;
868}
869
870static int sh_mobile_i2c_probe(struct platform_device *dev)
871{
872 struct sh_mobile_i2c_data *pd;
873 struct i2c_adapter *adap;
874 const struct sh_mobile_dt_config *config;
875 int ret;
876 u32 bus_speed;
877
878 pd = devm_kzalloc(dev: &dev->dev, size: sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
879 if (!pd)
880 return -ENOMEM;
881
882 pd->clk = devm_clk_get(dev: &dev->dev, NULL);
883 if (IS_ERR(ptr: pd->clk)) {
884 dev_err(&dev->dev, "cannot get clock\n");
885 return PTR_ERR(ptr: pd->clk);
886 }
887
888 ret = sh_mobile_i2c_hook_irqs(dev, pd);
889 if (ret)
890 return ret;
891
892 pd->dev = &dev->dev;
893 platform_set_drvdata(pdev: dev, data: pd);
894
895 pd->reg = devm_platform_get_and_ioremap_resource(pdev: dev, index: 0, res: &pd->res);
896 if (IS_ERR(ptr: pd->reg))
897 return PTR_ERR(ptr: pd->reg);
898
899 ret = of_property_read_u32(np: dev->dev.of_node, propname: "clock-frequency", out_value: &bus_speed);
900 pd->bus_speed = (ret || !bus_speed) ? I2C_MAX_STANDARD_MODE_FREQ : bus_speed;
901 pd->clks_per_count = 1;
902
903 /* Newer variants come with two new bits in ICIC */
904 if (resource_size(res: pd->res) > 0x17)
905 pd->flags |= IIC_FLAG_HAS_ICIC67;
906
907 pm_runtime_enable(dev: &dev->dev);
908 pm_runtime_get_sync(dev: &dev->dev);
909
910 config = of_device_get_match_data(dev: &dev->dev);
911 if (config) {
912 pd->clks_per_count = config->clks_per_count;
913 ret = config->setup(pd);
914 } else {
915 ret = sh_mobile_i2c_init(pd);
916 }
917
918 pm_runtime_put_sync(dev: &dev->dev);
919 if (ret)
920 return ret;
921
922 /* Init DMA */
923 sg_init_table(&pd->sg, 1);
924 pd->dma_direction = DMA_NONE;
925 pd->dma_rx = pd->dma_tx = ERR_PTR(error: -EPROBE_DEFER);
926
927 /* setup the private data */
928 adap = &pd->adap;
929 i2c_set_adapdata(adap, data: pd);
930
931 adap->owner = THIS_MODULE;
932 adap->algo = &sh_mobile_i2c_algorithm;
933 adap->quirks = &sh_mobile_i2c_quirks;
934 adap->dev.parent = &dev->dev;
935 adap->retries = 5;
936 adap->nr = dev->id;
937 adap->dev.of_node = dev->dev.of_node;
938
939 strscpy(p: adap->name, q: dev->name, size: sizeof(adap->name));
940
941 spin_lock_init(&pd->lock);
942 init_waitqueue_head(&pd->wait);
943
944 ret = i2c_add_numbered_adapter(adap);
945 if (ret < 0) {
946 sh_mobile_i2c_release_dma(pd);
947 return ret;
948 }
949
950 dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed);
951
952 return 0;
953}
954
955static void sh_mobile_i2c_remove(struct platform_device *dev)
956{
957 struct sh_mobile_i2c_data *pd = platform_get_drvdata(pdev: dev);
958
959 i2c_del_adapter(adap: &pd->adap);
960 sh_mobile_i2c_release_dma(pd);
961 pm_runtime_disable(dev: &dev->dev);
962}
963
964static int sh_mobile_i2c_suspend(struct device *dev)
965{
966 struct sh_mobile_i2c_data *pd = dev_get_drvdata(dev);
967
968 i2c_mark_adapter_suspended(adap: &pd->adap);
969 return 0;
970}
971
972static int sh_mobile_i2c_resume(struct device *dev)
973{
974 struct sh_mobile_i2c_data *pd = dev_get_drvdata(dev);
975
976 i2c_mark_adapter_resumed(adap: &pd->adap);
977 return 0;
978}
979
980static const struct dev_pm_ops sh_mobile_i2c_pm_ops = {
981 NOIRQ_SYSTEM_SLEEP_PM_OPS(sh_mobile_i2c_suspend,
982 sh_mobile_i2c_resume)
983};
984
985static struct platform_driver sh_mobile_i2c_driver = {
986 .driver = {
987 .name = "i2c-sh_mobile",
988 .of_match_table = sh_mobile_i2c_dt_ids,
989 .pm = pm_sleep_ptr(&sh_mobile_i2c_pm_ops),
990 },
991 .probe = sh_mobile_i2c_probe,
992 .remove_new = sh_mobile_i2c_remove,
993};
994
995static int __init sh_mobile_i2c_adap_init(void)
996{
997 return platform_driver_register(&sh_mobile_i2c_driver);
998}
999subsys_initcall(sh_mobile_i2c_adap_init);
1000
1001static void __exit sh_mobile_i2c_adap_exit(void)
1002{
1003 platform_driver_unregister(&sh_mobile_i2c_driver);
1004}
1005module_exit(sh_mobile_i2c_adap_exit);
1006
1007MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
1008MODULE_AUTHOR("Magnus Damm");
1009MODULE_AUTHOR("Wolfram Sang");
1010MODULE_LICENSE("GPL v2");
1011MODULE_ALIAS("platform:i2c-sh_mobile");
1012

source code of linux/drivers/i2c/busses/i2c-sh_mobile.c