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Linux/drivers/i2c/busses/i2c-sh_mobile.c

  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 = (pd->msg->addr & 0x7f) << 1;
402                 *buf |= (pd->msg->flags & I2C_M_RD) ? 1 : 0;
403                 break;
404         default:
405                 *buf = pd->msg->buf[pd->pos];
406         }
407 }
408 
409 static int sh_mobile_i2c_isr_tx(struct sh_mobile_i2c_data *pd)
410 {
411         unsigned char data;
412 
413         if (pd->pos == pd->msg->len) {
414                 /* Send stop if we haven't yet (DMA case) */
415                 if (pd->send_stop && pd->stop_after_dma)
416                         i2c_op(pd, OP_TX_STOP, 0);
417                 return 1;
418         }
419 
420         sh_mobile_i2c_get_data(pd, &data);
421 
422         if (sh_mobile_i2c_is_last_byte(pd))
423                 i2c_op(pd, OP_TX_STOP_DATA, data);
424         else if (sh_mobile_i2c_is_first_byte(pd))
425                 i2c_op(pd, OP_TX_FIRST, data);
426         else
427                 i2c_op(pd, OP_TX, data);
428 
429         pd->pos++;
430         return 0;
431 }
432 
433 static int sh_mobile_i2c_isr_rx(struct sh_mobile_i2c_data *pd)
434 {
435         unsigned char data;
436         int real_pos;
437 
438         do {
439                 if (pd->pos <= -1) {
440                         sh_mobile_i2c_get_data(pd, &data);
441 
442                         if (sh_mobile_i2c_is_first_byte(pd))
443                                 i2c_op(pd, OP_TX_FIRST, data);
444                         else
445                                 i2c_op(pd, OP_TX, data);
446                         break;
447                 }
448 
449                 if (pd->pos == 0) {
450                         i2c_op(pd, OP_TX_TO_RX, 0);
451                         break;
452                 }
453 
454                 real_pos = pd->pos - 2;
455 
456                 if (pd->pos == pd->msg->len) {
457                         if (pd->stop_after_dma) {
458                                 /* Simulate PIO end condition after DMA transfer */
459                                 i2c_op(pd, OP_RX_STOP, 0);
460                                 pd->pos++;
461                                 break;
462                         }
463 
464                         if (real_pos < 0) {
465                                 i2c_op(pd, OP_RX_STOP, 0);
466                                 break;
467                         }
468                         data = i2c_op(pd, OP_RX_STOP_DATA, 0);
469                 } else
470                         data = i2c_op(pd, OP_RX, 0);
471 
472                 if (real_pos >= 0)
473                         pd->msg->buf[real_pos] = data;
474         } while (0);
475 
476         pd->pos++;
477         return pd->pos == (pd->msg->len + 2);
478 }
479 
480 static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
481 {
482         struct sh_mobile_i2c_data *pd = dev_id;
483         unsigned char sr;
484         int wakeup = 0;
485 
486         sr = iic_rd(pd, ICSR);
487         pd->sr |= sr; /* remember state */
488 
489         dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
490                (pd->msg->flags & I2C_M_RD) ? "read" : "write",
491                pd->pos, pd->msg->len);
492 
493         /* Kick off TxDMA after preface was done */
494         if (pd->dma_direction == DMA_TO_DEVICE && pd->pos == 0)
495                 iic_set_clr(pd, ICIC, ICIC_TDMAE, 0);
496         else if (sr & (ICSR_AL | ICSR_TACK))
497                 /* don't interrupt transaction - continue to issue stop */
498                 iic_wr(pd, ICSR, sr & ~(ICSR_AL | ICSR_TACK));
499         else if (pd->msg->flags & I2C_M_RD)
500                 wakeup = sh_mobile_i2c_isr_rx(pd);
501         else
502                 wakeup = sh_mobile_i2c_isr_tx(pd);
503 
504         /* Kick off RxDMA after preface was done */
505         if (pd->dma_direction == DMA_FROM_DEVICE && pd->pos == 1)
506                 iic_set_clr(pd, ICIC, ICIC_RDMAE, 0);
507 
508         if (sr & ICSR_WAIT) /* TODO: add delay here to support slow acks */
509                 iic_wr(pd, ICSR, sr & ~ICSR_WAIT);
510 
511         if (wakeup) {
512                 pd->sr |= SW_DONE;
513                 wake_up(&pd->wait);
514         }
515 
516         /* defeat write posting to avoid spurious WAIT interrupts */
517         iic_rd(pd, ICSR);
518 
519         return IRQ_HANDLED;
520 }
521 
522 static void sh_mobile_i2c_dma_unmap(struct sh_mobile_i2c_data *pd)
523 {
524         struct dma_chan *chan = pd->dma_direction == DMA_FROM_DEVICE
525                                 ? pd->dma_rx : pd->dma_tx;
526 
527         dma_unmap_single(chan->device->dev, sg_dma_address(&pd->sg),
528                          pd->msg->len, pd->dma_direction);
529 
530         pd->dma_direction = DMA_NONE;
531 }
532 
533 static void sh_mobile_i2c_cleanup_dma(struct sh_mobile_i2c_data *pd)
534 {
535         if (pd->dma_direction == DMA_NONE)
536                 return;
537         else if (pd->dma_direction == DMA_FROM_DEVICE)
538                 dmaengine_terminate_all(pd->dma_rx);
539         else if (pd->dma_direction == DMA_TO_DEVICE)
540                 dmaengine_terminate_all(pd->dma_tx);
541 
542         sh_mobile_i2c_dma_unmap(pd);
543 }
544 
545 static void sh_mobile_i2c_dma_callback(void *data)
546 {
547         struct sh_mobile_i2c_data *pd = data;
548 
549         sh_mobile_i2c_dma_unmap(pd);
550         pd->pos = pd->msg->len;
551         pd->stop_after_dma = true;
552 
553         iic_set_clr(pd, ICIC, 0, ICIC_TDMAE | ICIC_RDMAE);
554 }
555 
556 static struct dma_chan *sh_mobile_i2c_request_dma_chan(struct device *dev,
557                                 enum dma_transfer_direction dir, dma_addr_t port_addr)
558 {
559         struct dma_chan *chan;
560         struct dma_slave_config cfg;
561         char *chan_name = dir == DMA_MEM_TO_DEV ? "tx" : "rx";
562         int ret;
563 
564         chan = dma_request_slave_channel_reason(dev, chan_name);
565         if (IS_ERR(chan)) {
566                 ret = PTR_ERR(chan);
567                 dev_dbg(dev, "request_channel failed for %s (%d)\n", chan_name, ret);
568                 return chan;
569         }
570 
571         memset(&cfg, 0, sizeof(cfg));
572         cfg.direction = dir;
573         if (dir == DMA_MEM_TO_DEV) {
574                 cfg.dst_addr = port_addr;
575                 cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
576         } else {
577                 cfg.src_addr = port_addr;
578                 cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
579         }
580 
581         ret = dmaengine_slave_config(chan, &cfg);
582         if (ret) {
583                 dev_dbg(dev, "slave_config failed for %s (%d)\n", chan_name, ret);
584                 dma_release_channel(chan);
585                 return ERR_PTR(ret);
586         }
587 
588         dev_dbg(dev, "got DMA channel for %s\n", chan_name);
589         return chan;
590 }
591 
592 static void sh_mobile_i2c_xfer_dma(struct sh_mobile_i2c_data *pd)
593 {
594         bool read = pd->msg->flags & I2C_M_RD;
595         enum dma_data_direction dir = read ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
596         struct dma_chan *chan = read ? pd->dma_rx : pd->dma_tx;
597         struct dma_async_tx_descriptor *txdesc;
598         dma_addr_t dma_addr;
599         dma_cookie_t cookie;
600 
601         if (PTR_ERR(chan) == -EPROBE_DEFER) {
602                 if (read)
603                         chan = pd->dma_rx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_DEV_TO_MEM,
604                                                                            pd->res->start + ICDR);
605                 else
606                         chan = pd->dma_tx = sh_mobile_i2c_request_dma_chan(pd->dev, DMA_MEM_TO_DEV,
607                                                                            pd->res->start + ICDR);
608         }
609 
610         if (IS_ERR(chan))
611                 return;
612 
613         dma_addr = dma_map_single(chan->device->dev, pd->msg->buf, pd->msg->len, dir);
614         if (dma_mapping_error(pd->dev, dma_addr)) {
615                 dev_dbg(pd->dev, "dma map failed, using PIO\n");
616                 return;
617         }
618 
619         sg_dma_len(&pd->sg) = pd->msg->len;
620         sg_dma_address(&pd->sg) = dma_addr;
621 
622         pd->dma_direction = dir;
623 
624         txdesc = dmaengine_prep_slave_sg(chan, &pd->sg, 1,
625                                          read ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV,
626                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
627         if (!txdesc) {
628                 dev_dbg(pd->dev, "dma prep slave sg failed, using PIO\n");
629                 sh_mobile_i2c_cleanup_dma(pd);
630                 return;
631         }
632 
633         txdesc->callback = sh_mobile_i2c_dma_callback;
634         txdesc->callback_param = pd;
635 
636         cookie = dmaengine_submit(txdesc);
637         if (dma_submit_error(cookie)) {
638                 dev_dbg(pd->dev, "submitting dma failed, using PIO\n");
639                 sh_mobile_i2c_cleanup_dma(pd);
640                 return;
641         }
642 
643         dma_async_issue_pending(chan);
644 }
645 
646 static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg,
647                     bool do_init)
648 {
649         if (usr_msg->len == 0 && (usr_msg->flags & I2C_M_RD)) {
650                 dev_err(pd->dev, "Unsupported zero length i2c read\n");
651                 return -EOPNOTSUPP;
652         }
653 
654         if (do_init) {
655                 /* Initialize channel registers */
656                 iic_set_clr(pd, ICCR, 0, ICCR_ICE);
657 
658                 /* Enable channel and configure rx ack */
659                 iic_set_clr(pd, ICCR, ICCR_ICE, 0);
660 
661                 /* Set the clock */
662                 iic_wr(pd, ICCL, pd->iccl & 0xff);
663                 iic_wr(pd, ICCH, pd->icch & 0xff);
664         }
665 
666         pd->msg = usr_msg;
667         pd->pos = -1;
668         pd->sr = 0;
669 
670         if (pd->msg->len > 8)
671                 sh_mobile_i2c_xfer_dma(pd);
672 
673         /* Enable all interrupts to begin with */
674         iic_wr(pd, ICIC, ICIC_DTEE | ICIC_WAITE | ICIC_ALE | ICIC_TACKE);
675         return 0;
676 }
677 
678 static int poll_dte(struct sh_mobile_i2c_data *pd)
679 {
680         int i;
681 
682         for (i = 1000; i; i--) {
683                 u_int8_t val = iic_rd(pd, ICSR);
684 
685                 if (val & ICSR_DTE)
686                         break;
687 
688                 if (val & ICSR_TACK)
689                         return -ENXIO;
690 
691                 udelay(10);
692         }
693 
694         return i ? 0 : -ETIMEDOUT;
695 }
696 
697 static int poll_busy(struct sh_mobile_i2c_data *pd)
698 {
699         int i;
700 
701         for (i = 1000; i; i--) {
702                 u_int8_t val = iic_rd(pd, ICSR);
703 
704                 dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
705 
706                 /* the interrupt handler may wake us up before the
707                  * transfer is finished, so poll the hardware
708                  * until we're done.
709                  */
710                 if (!(val & ICSR_BUSY)) {
711                         /* handle missing acknowledge and arbitration lost */
712                         val |= pd->sr;
713                         if (val & ICSR_TACK)
714                                 return -ENXIO;
715                         if (val & ICSR_AL)
716                                 return -EAGAIN;
717                         break;
718                 }
719 
720                 udelay(10);
721         }
722 
723         return i ? 0 : -ETIMEDOUT;
724 }
725 
726 static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
727                               struct i2c_msg *msgs,
728                               int num)
729 {
730         struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
731         struct i2c_msg  *msg;
732         int err = 0;
733         int i;
734         long timeout;
735 
736         activate_ch(pd);
737 
738         /* Process all messages */
739         for (i = 0; i < num; i++) {
740                 bool do_start = pd->send_stop || !i;
741                 msg = &msgs[i];
742                 pd->send_stop = i == num - 1 || msg->flags & I2C_M_STOP;
743                 pd->stop_after_dma = false;
744 
745                 err = start_ch(pd, msg, do_start);
746                 if (err)
747                         break;
748 
749                 if (do_start)
750                         i2c_op(pd, OP_START, 0);
751 
752                 /* The interrupt handler takes care of the rest... */
753                 timeout = wait_event_timeout(pd->wait,
754                                        pd->sr & (ICSR_TACK | SW_DONE),
755                                        adapter->timeout);
756                 if (!timeout) {
757                         dev_err(pd->dev, "Transfer request timed out\n");
758                         if (pd->dma_direction != DMA_NONE)
759                                 sh_mobile_i2c_cleanup_dma(pd);
760 
761                         err = -ETIMEDOUT;
762                         break;
763                 }
764 
765                 if (pd->send_stop)
766                         err = poll_busy(pd);
767                 else
768                         err = poll_dte(pd);
769                 if (err < 0)
770                         break;
771         }
772 
773         deactivate_ch(pd);
774 
775         if (!err)
776                 err = num;
777         return err;
778 }
779 
780 static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
781 {
782         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
783 }
784 
785 static struct i2c_algorithm sh_mobile_i2c_algorithm = {
786         .functionality  = sh_mobile_i2c_func,
787         .master_xfer    = sh_mobile_i2c_xfer,
788 };
789 
790 /*
791  * r8a7740 chip has lasting errata on I2C I/O pad reset.
792  * this is work-around for it.
793  */
794 static void sh_mobile_i2c_r8a7740_workaround(struct sh_mobile_i2c_data *pd)
795 {
796         iic_set_clr(pd, ICCR, ICCR_ICE, 0);
797         iic_rd(pd, ICCR); /* dummy read */
798 
799         iic_set_clr(pd, ICSTART, ICSTART_ICSTART, 0);
800         iic_rd(pd, ICSTART); /* dummy read */
801 
802         udelay(10);
803 
804         iic_wr(pd, ICCR, ICCR_SCP);
805         iic_wr(pd, ICSTART, 0);
806 
807         udelay(10);
808 
809         iic_wr(pd, ICCR, ICCR_TRS);
810         udelay(10);
811         iic_wr(pd, ICCR, 0);
812         udelay(10);
813         iic_wr(pd, ICCR, ICCR_TRS);
814         udelay(10);
815 }
816 
817 static const struct sh_mobile_dt_config default_dt_config = {
818         .clks_per_count = 1,
819 };
820 
821 static const struct sh_mobile_dt_config fast_clock_dt_config = {
822         .clks_per_count = 2,
823 };
824 
825 static const struct sh_mobile_dt_config r8a7740_dt_config = {
826         .clks_per_count = 1,
827         .setup = sh_mobile_i2c_r8a7740_workaround,
828 };
829 
830 static const struct of_device_id sh_mobile_i2c_dt_ids[] = {
831         { .compatible = "renesas,rmobile-iic", .data = &default_dt_config },
832         { .compatible = "renesas,iic-r8a73a4", .data = &fast_clock_dt_config },
833         { .compatible = "renesas,iic-r8a7740", .data = &r8a7740_dt_config },
834         { .compatible = "renesas,iic-r8a7790", .data = &fast_clock_dt_config },
835         { .compatible = "renesas,iic-r8a7791", .data = &fast_clock_dt_config },
836         { .compatible = "renesas,iic-r8a7792", .data = &fast_clock_dt_config },
837         { .compatible = "renesas,iic-r8a7793", .data = &fast_clock_dt_config },
838         { .compatible = "renesas,iic-r8a7794", .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                 dev_err(&dev->dev, "cannot add numbered adapter\n");
985                 return ret;
986         }
987 
988         dev_info(&dev->dev, "I2C adapter %d, bus speed %lu Hz\n", adap->nr, pd->bus_speed);
989 
990         return 0;
991 }
992 
993 static int sh_mobile_i2c_remove(struct platform_device *dev)
994 {
995         struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
996 
997         i2c_del_adapter(&pd->adap);
998         sh_mobile_i2c_release_dma(pd);
999         pm_runtime_disable(&dev->dev);
1000         return 0;
1001 }
1002 
1003 static int sh_mobile_i2c_runtime_nop(struct device *dev)
1004 {
1005         /* Runtime PM callback shared between ->runtime_suspend()
1006          * and ->runtime_resume(). Simply returns success.
1007          *
1008          * This driver re-initializes all registers after
1009          * pm_runtime_get_sync() anyway so there is no need
1010          * to save and restore registers here.
1011          */
1012         return 0;
1013 }
1014 
1015 static const struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = {
1016         .runtime_suspend = sh_mobile_i2c_runtime_nop,
1017         .runtime_resume = sh_mobile_i2c_runtime_nop,
1018 };
1019 
1020 static struct platform_driver sh_mobile_i2c_driver = {
1021         .driver         = {
1022                 .name           = "i2c-sh_mobile",
1023                 .pm             = &sh_mobile_i2c_dev_pm_ops,
1024                 .of_match_table = sh_mobile_i2c_dt_ids,
1025         },
1026         .probe          = sh_mobile_i2c_probe,
1027         .remove         = sh_mobile_i2c_remove,
1028 };
1029 
1030 static int __init sh_mobile_i2c_adap_init(void)
1031 {
1032         return platform_driver_register(&sh_mobile_i2c_driver);
1033 }
1034 subsys_initcall(sh_mobile_i2c_adap_init);
1035 
1036 static void __exit sh_mobile_i2c_adap_exit(void)
1037 {
1038         platform_driver_unregister(&sh_mobile_i2c_driver);
1039 }
1040 module_exit(sh_mobile_i2c_adap_exit);
1041 
1042 MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
1043 MODULE_AUTHOR("Magnus Damm and Wolfram Sang");
1044 MODULE_LICENSE("GPL v2");
1045 MODULE_ALIAS("platform:i2c-sh_mobile");
1046 

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