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[deliverable/linux.git] / drivers / i2c / busses / i2c-at91.c
1 /*
2 * i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
3 *
4 * Copyright (C) 2011 Weinmann Medical GmbH
5 * Author: Nikolaus Voss <n.voss@weinmann.de>
6 *
7 * Evolved from original work by:
8 * Copyright (C) 2004 Rick Bronson
9 * Converted to 2.6 by Andrew Victor <andrew@sanpeople.com>
10 *
11 * Borrowed heavily from original work by:
12 * Copyright (C) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
18 */
19
20 #include <linux/clk.h>
21 #include <linux/completion.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/dmaengine.h>
24 #include <linux/err.h>
25 #include <linux/i2c.h>
26 #include <linux/interrupt.h>
27 #include <linux/io.h>
28 #include <linux/module.h>
29 #include <linux/of.h>
30 #include <linux/of_device.h>
31 #include <linux/platform_device.h>
32 #include <linux/slab.h>
33 #include <linux/platform_data/dma-atmel.h>
34 #include <linux/pm_runtime.h>
35 #include <linux/pinctrl/consumer.h>
36
37 #define DEFAULT_TWI_CLK_HZ 100000 /* max 400 Kbits/s */
38 #define AT91_I2C_TIMEOUT msecs_to_jiffies(100) /* transfer timeout */
39 #define AT91_I2C_DMA_THRESHOLD 8 /* enable DMA if transfer size is bigger than this threshold */
40 #define AUTOSUSPEND_TIMEOUT 2000
41
42 /* AT91 TWI register definitions */
43 #define AT91_TWI_CR 0x0000 /* Control Register */
44 #define AT91_TWI_START 0x0001 /* Send a Start Condition */
45 #define AT91_TWI_STOP 0x0002 /* Send a Stop Condition */
46 #define AT91_TWI_MSEN 0x0004 /* Master Transfer Enable */
47 #define AT91_TWI_SVDIS 0x0020 /* Slave Transfer Disable */
48 #define AT91_TWI_QUICK 0x0040 /* SMBus quick command */
49 #define AT91_TWI_SWRST 0x0080 /* Software Reset */
50
51 #define AT91_TWI_MMR 0x0004 /* Master Mode Register */
52 #define AT91_TWI_IADRSZ_1 0x0100 /* Internal Device Address Size */
53 #define AT91_TWI_MREAD 0x1000 /* Master Read Direction */
54
55 #define AT91_TWI_IADR 0x000c /* Internal Address Register */
56
57 #define AT91_TWI_CWGR 0x0010 /* Clock Waveform Generator Reg */
58
59 #define AT91_TWI_SR 0x0020 /* Status Register */
60 #define AT91_TWI_TXCOMP 0x0001 /* Transmission Complete */
61 #define AT91_TWI_RXRDY 0x0002 /* Receive Holding Register Ready */
62 #define AT91_TWI_TXRDY 0x0004 /* Transmit Holding Register Ready */
63
64 #define AT91_TWI_OVRE 0x0040 /* Overrun Error */
65 #define AT91_TWI_UNRE 0x0080 /* Underrun Error */
66 #define AT91_TWI_NACK 0x0100 /* Not Acknowledged */
67
68 #define AT91_TWI_IER 0x0024 /* Interrupt Enable Register */
69 #define AT91_TWI_IDR 0x0028 /* Interrupt Disable Register */
70 #define AT91_TWI_IMR 0x002c /* Interrupt Mask Register */
71 #define AT91_TWI_RHR 0x0030 /* Receive Holding Register */
72 #define AT91_TWI_THR 0x0034 /* Transmit Holding Register */
73
74 struct at91_twi_pdata {
75 unsigned clk_max_div;
76 unsigned clk_offset;
77 bool has_unre_flag;
78 struct at_dma_slave dma_slave;
79 };
80
81 struct at91_twi_dma {
82 struct dma_chan *chan_rx;
83 struct dma_chan *chan_tx;
84 struct scatterlist sg;
85 struct dma_async_tx_descriptor *data_desc;
86 enum dma_data_direction direction;
87 bool buf_mapped;
88 bool xfer_in_progress;
89 };
90
91 struct at91_twi_dev {
92 struct device *dev;
93 void __iomem *base;
94 struct completion cmd_complete;
95 struct clk *clk;
96 u8 *buf;
97 size_t buf_len;
98 struct i2c_msg *msg;
99 int irq;
100 unsigned imr;
101 unsigned transfer_status;
102 struct i2c_adapter adapter;
103 unsigned twi_cwgr_reg;
104 struct at91_twi_pdata *pdata;
105 bool use_dma;
106 bool recv_len_abort;
107 struct at91_twi_dma dma;
108 };
109
110 static unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg)
111 {
112 return readl_relaxed(dev->base + reg);
113 }
114
115 static void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val)
116 {
117 writel_relaxed(val, dev->base + reg);
118 }
119
120 static void at91_disable_twi_interrupts(struct at91_twi_dev *dev)
121 {
122 at91_twi_write(dev, AT91_TWI_IDR,
123 AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY);
124 }
125
126 static void at91_twi_irq_save(struct at91_twi_dev *dev)
127 {
128 dev->imr = at91_twi_read(dev, AT91_TWI_IMR) & 0x7;
129 at91_disable_twi_interrupts(dev);
130 }
131
132 static void at91_twi_irq_restore(struct at91_twi_dev *dev)
133 {
134 at91_twi_write(dev, AT91_TWI_IER, dev->imr);
135 }
136
137 static void at91_init_twi_bus(struct at91_twi_dev *dev)
138 {
139 at91_disable_twi_interrupts(dev);
140 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST);
141 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_MSEN);
142 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SVDIS);
143 at91_twi_write(dev, AT91_TWI_CWGR, dev->twi_cwgr_reg);
144 }
145
146 /*
147 * Calculate symmetric clock as stated in datasheet:
148 * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
149 */
150 static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
151 {
152 int ckdiv, cdiv, div;
153 struct at91_twi_pdata *pdata = dev->pdata;
154 int offset = pdata->clk_offset;
155 int max_ckdiv = pdata->clk_max_div;
156
157 div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
158 2 * twi_clk) - offset);
159 ckdiv = fls(div >> 8);
160 cdiv = div >> ckdiv;
161
162 if (ckdiv > max_ckdiv) {
163 dev_warn(dev->dev, "%d exceeds ckdiv max value which is %d.\n",
164 ckdiv, max_ckdiv);
165 ckdiv = max_ckdiv;
166 cdiv = 255;
167 }
168
169 dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv;
170 dev_dbg(dev->dev, "cdiv %d ckdiv %d\n", cdiv, ckdiv);
171 }
172
173 static void at91_twi_dma_cleanup(struct at91_twi_dev *dev)
174 {
175 struct at91_twi_dma *dma = &dev->dma;
176
177 at91_twi_irq_save(dev);
178
179 if (dma->xfer_in_progress) {
180 if (dma->direction == DMA_FROM_DEVICE)
181 dmaengine_terminate_all(dma->chan_rx);
182 else
183 dmaengine_terminate_all(dma->chan_tx);
184 dma->xfer_in_progress = false;
185 }
186 if (dma->buf_mapped) {
187 dma_unmap_single(dev->dev, sg_dma_address(&dma->sg),
188 dev->buf_len, dma->direction);
189 dma->buf_mapped = false;
190 }
191
192 at91_twi_irq_restore(dev);
193 }
194
195 static void at91_twi_write_next_byte(struct at91_twi_dev *dev)
196 {
197 if (dev->buf_len <= 0)
198 return;
199
200 at91_twi_write(dev, AT91_TWI_THR, *dev->buf);
201
202 /* send stop when last byte has been written */
203 if (--dev->buf_len == 0)
204 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
205
206 dev_dbg(dev->dev, "wrote 0x%x, to go %d\n", *dev->buf, dev->buf_len);
207
208 ++dev->buf;
209 }
210
211 static void at91_twi_write_data_dma_callback(void *data)
212 {
213 struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
214
215 dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg),
216 dev->buf_len, DMA_TO_DEVICE);
217
218 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
219 }
220
221 static void at91_twi_write_data_dma(struct at91_twi_dev *dev)
222 {
223 dma_addr_t dma_addr;
224 struct dma_async_tx_descriptor *txdesc;
225 struct at91_twi_dma *dma = &dev->dma;
226 struct dma_chan *chan_tx = dma->chan_tx;
227
228 if (dev->buf_len <= 0)
229 return;
230
231 dma->direction = DMA_TO_DEVICE;
232
233 at91_twi_irq_save(dev);
234 dma_addr = dma_map_single(dev->dev, dev->buf, dev->buf_len,
235 DMA_TO_DEVICE);
236 if (dma_mapping_error(dev->dev, dma_addr)) {
237 dev_err(dev->dev, "dma map failed\n");
238 return;
239 }
240 dma->buf_mapped = true;
241 at91_twi_irq_restore(dev);
242 sg_dma_len(&dma->sg) = dev->buf_len;
243 sg_dma_address(&dma->sg) = dma_addr;
244
245 txdesc = dmaengine_prep_slave_sg(chan_tx, &dma->sg, 1, DMA_MEM_TO_DEV,
246 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
247 if (!txdesc) {
248 dev_err(dev->dev, "dma prep slave sg failed\n");
249 goto error;
250 }
251
252 txdesc->callback = at91_twi_write_data_dma_callback;
253 txdesc->callback_param = dev;
254
255 dma->xfer_in_progress = true;
256 dmaengine_submit(txdesc);
257 dma_async_issue_pending(chan_tx);
258
259 return;
260
261 error:
262 at91_twi_dma_cleanup(dev);
263 }
264
265 static void at91_twi_read_next_byte(struct at91_twi_dev *dev)
266 {
267 if (dev->buf_len <= 0)
268 return;
269
270 *dev->buf = at91_twi_read(dev, AT91_TWI_RHR) & 0xff;
271 --dev->buf_len;
272
273 /* return if aborting, we only needed to read RHR to clear RXRDY*/
274 if (dev->recv_len_abort)
275 return;
276
277 /* handle I2C_SMBUS_BLOCK_DATA */
278 if (unlikely(dev->msg->flags & I2C_M_RECV_LEN)) {
279 /* ensure length byte is a valid value */
280 if (*dev->buf <= I2C_SMBUS_BLOCK_MAX && *dev->buf > 0) {
281 dev->msg->flags &= ~I2C_M_RECV_LEN;
282 dev->buf_len += *dev->buf;
283 dev->msg->len = dev->buf_len + 1;
284 dev_dbg(dev->dev, "received block length %d\n",
285 dev->buf_len);
286 } else {
287 /* abort and send the stop by reading one more byte */
288 dev->recv_len_abort = true;
289 dev->buf_len = 1;
290 }
291 }
292
293 /* send stop if second but last byte has been read */
294 if (dev->buf_len == 1)
295 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
296
297 dev_dbg(dev->dev, "read 0x%x, to go %d\n", *dev->buf, dev->buf_len);
298
299 ++dev->buf;
300 }
301
302 static void at91_twi_read_data_dma_callback(void *data)
303 {
304 struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
305
306 dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg),
307 dev->buf_len, DMA_FROM_DEVICE);
308
309 /* The last two bytes have to be read without using dma */
310 dev->buf += dev->buf_len - 2;
311 dev->buf_len = 2;
312 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_RXRDY);
313 }
314
315 static void at91_twi_read_data_dma(struct at91_twi_dev *dev)
316 {
317 dma_addr_t dma_addr;
318 struct dma_async_tx_descriptor *rxdesc;
319 struct at91_twi_dma *dma = &dev->dma;
320 struct dma_chan *chan_rx = dma->chan_rx;
321
322 dma->direction = DMA_FROM_DEVICE;
323
324 /* Keep in mind that we won't use dma to read the last two bytes */
325 at91_twi_irq_save(dev);
326 dma_addr = dma_map_single(dev->dev, dev->buf, dev->buf_len - 2,
327 DMA_FROM_DEVICE);
328 if (dma_mapping_error(dev->dev, dma_addr)) {
329 dev_err(dev->dev, "dma map failed\n");
330 return;
331 }
332 dma->buf_mapped = true;
333 at91_twi_irq_restore(dev);
334 dma->sg.dma_address = dma_addr;
335 sg_dma_len(&dma->sg) = dev->buf_len - 2;
336
337 rxdesc = dmaengine_prep_slave_sg(chan_rx, &dma->sg, 1, DMA_DEV_TO_MEM,
338 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
339 if (!rxdesc) {
340 dev_err(dev->dev, "dma prep slave sg failed\n");
341 goto error;
342 }
343
344 rxdesc->callback = at91_twi_read_data_dma_callback;
345 rxdesc->callback_param = dev;
346
347 dma->xfer_in_progress = true;
348 dmaengine_submit(rxdesc);
349 dma_async_issue_pending(dma->chan_rx);
350
351 return;
352
353 error:
354 at91_twi_dma_cleanup(dev);
355 }
356
357 static irqreturn_t atmel_twi_interrupt(int irq, void *dev_id)
358 {
359 struct at91_twi_dev *dev = dev_id;
360 const unsigned status = at91_twi_read(dev, AT91_TWI_SR);
361 const unsigned irqstatus = status & at91_twi_read(dev, AT91_TWI_IMR);
362
363 if (!irqstatus)
364 return IRQ_NONE;
365 else if (irqstatus & AT91_TWI_RXRDY)
366 at91_twi_read_next_byte(dev);
367 else if (irqstatus & AT91_TWI_TXRDY)
368 at91_twi_write_next_byte(dev);
369
370 /* catch error flags */
371 dev->transfer_status |= status;
372
373 if (irqstatus & AT91_TWI_TXCOMP) {
374 at91_disable_twi_interrupts(dev);
375 complete(&dev->cmd_complete);
376 }
377
378 return IRQ_HANDLED;
379 }
380
381 static int at91_do_twi_transfer(struct at91_twi_dev *dev)
382 {
383 int ret;
384 bool has_unre_flag = dev->pdata->has_unre_flag;
385
386 dev_dbg(dev->dev, "transfer: %s %d bytes.\n",
387 (dev->msg->flags & I2C_M_RD) ? "read" : "write", dev->buf_len);
388
389 reinit_completion(&dev->cmd_complete);
390 dev->transfer_status = 0;
391
392 if (!dev->buf_len) {
393 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_QUICK);
394 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
395 } else if (dev->msg->flags & I2C_M_RD) {
396 unsigned start_flags = AT91_TWI_START;
397
398 if (at91_twi_read(dev, AT91_TWI_SR) & AT91_TWI_RXRDY) {
399 dev_err(dev->dev, "RXRDY still set!");
400 at91_twi_read(dev, AT91_TWI_RHR);
401 }
402
403 /* if only one byte is to be read, immediately stop transfer */
404 if (dev->buf_len <= 1 && !(dev->msg->flags & I2C_M_RECV_LEN))
405 start_flags |= AT91_TWI_STOP;
406 at91_twi_write(dev, AT91_TWI_CR, start_flags);
407 /*
408 * When using dma, the last byte has to be read manually in
409 * order to not send the stop command too late and then
410 * to receive extra data. In practice, there are some issues
411 * if you use the dma to read n-1 bytes because of latency.
412 * Reading n-2 bytes with dma and the two last ones manually
413 * seems to be the best solution.
414 */
415 if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) {
416 at91_twi_read_data_dma(dev);
417 /*
418 * It is important to enable TXCOMP irq here because
419 * doing it only when transferring the last two bytes
420 * will mask NACK errors since TXCOMP is set when a
421 * NACK occurs.
422 */
423 at91_twi_write(dev, AT91_TWI_IER,
424 AT91_TWI_TXCOMP);
425 } else
426 at91_twi_write(dev, AT91_TWI_IER,
427 AT91_TWI_TXCOMP | AT91_TWI_RXRDY);
428 } else {
429 if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) {
430 at91_twi_write_data_dma(dev);
431 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
432 } else {
433 at91_twi_write_next_byte(dev);
434 at91_twi_write(dev, AT91_TWI_IER,
435 AT91_TWI_TXCOMP | AT91_TWI_TXRDY);
436 }
437 }
438
439 ret = wait_for_completion_timeout(&dev->cmd_complete,
440 dev->adapter.timeout);
441 if (ret == 0) {
442 dev_err(dev->dev, "controller timed out\n");
443 at91_init_twi_bus(dev);
444 ret = -ETIMEDOUT;
445 goto error;
446 }
447 if (dev->transfer_status & AT91_TWI_NACK) {
448 dev_dbg(dev->dev, "received nack\n");
449 ret = -EREMOTEIO;
450 goto error;
451 }
452 if (dev->transfer_status & AT91_TWI_OVRE) {
453 dev_err(dev->dev, "overrun while reading\n");
454 ret = -EIO;
455 goto error;
456 }
457 if (has_unre_flag && dev->transfer_status & AT91_TWI_UNRE) {
458 dev_err(dev->dev, "underrun while writing\n");
459 ret = -EIO;
460 goto error;
461 }
462 if (dev->recv_len_abort) {
463 dev_err(dev->dev, "invalid smbus block length recvd\n");
464 ret = -EPROTO;
465 goto error;
466 }
467
468 dev_dbg(dev->dev, "transfer complete\n");
469
470 return 0;
471
472 error:
473 at91_twi_dma_cleanup(dev);
474 return ret;
475 }
476
477 static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
478 {
479 struct at91_twi_dev *dev = i2c_get_adapdata(adap);
480 int ret;
481 unsigned int_addr_flag = 0;
482 struct i2c_msg *m_start = msg;
483
484 dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
485
486 ret = pm_runtime_get_sync(dev->dev);
487 if (ret < 0)
488 goto out;
489
490 /*
491 * The hardware can handle at most two messages concatenated by a
492 * repeated start via it's internal address feature.
493 */
494 if (num > 2) {
495 dev_err(dev->dev,
496 "cannot handle more than two concatenated messages.\n");
497 ret = 0;
498 goto out;
499 } else if (num == 2) {
500 int internal_address = 0;
501 int i;
502
503 if (msg->flags & I2C_M_RD) {
504 dev_err(dev->dev, "first transfer must be write.\n");
505 ret = -EINVAL;
506 goto out;
507 }
508 if (msg->len > 3) {
509 dev_err(dev->dev, "first message size must be <= 3.\n");
510 ret = -EINVAL;
511 goto out;
512 }
513
514 /* 1st msg is put into the internal address, start with 2nd */
515 m_start = &msg[1];
516 for (i = 0; i < msg->len; ++i) {
517 const unsigned addr = msg->buf[msg->len - 1 - i];
518
519 internal_address |= addr << (8 * i);
520 int_addr_flag += AT91_TWI_IADRSZ_1;
521 }
522 at91_twi_write(dev, AT91_TWI_IADR, internal_address);
523 }
524
525 at91_twi_write(dev, AT91_TWI_MMR, (m_start->addr << 16) | int_addr_flag
526 | ((m_start->flags & I2C_M_RD) ? AT91_TWI_MREAD : 0));
527
528 dev->buf_len = m_start->len;
529 dev->buf = m_start->buf;
530 dev->msg = m_start;
531 dev->recv_len_abort = false;
532
533 ret = at91_do_twi_transfer(dev);
534
535 ret = (ret < 0) ? ret : num;
536 out:
537 pm_runtime_mark_last_busy(dev->dev);
538 pm_runtime_put_autosuspend(dev->dev);
539
540 return ret;
541 }
542
543 static u32 at91_twi_func(struct i2c_adapter *adapter)
544 {
545 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
546 | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
547 }
548
549 static struct i2c_algorithm at91_twi_algorithm = {
550 .master_xfer = at91_twi_xfer,
551 .functionality = at91_twi_func,
552 };
553
554 static struct at91_twi_pdata at91rm9200_config = {
555 .clk_max_div = 5,
556 .clk_offset = 3,
557 .has_unre_flag = true,
558 };
559
560 static struct at91_twi_pdata at91sam9261_config = {
561 .clk_max_div = 5,
562 .clk_offset = 4,
563 .has_unre_flag = false,
564 };
565
566 static struct at91_twi_pdata at91sam9260_config = {
567 .clk_max_div = 7,
568 .clk_offset = 4,
569 .has_unre_flag = false,
570 };
571
572 static struct at91_twi_pdata at91sam9g20_config = {
573 .clk_max_div = 7,
574 .clk_offset = 4,
575 .has_unre_flag = false,
576 };
577
578 static struct at91_twi_pdata at91sam9g10_config = {
579 .clk_max_div = 7,
580 .clk_offset = 4,
581 .has_unre_flag = false,
582 };
583
584 static const struct platform_device_id at91_twi_devtypes[] = {
585 {
586 .name = "i2c-at91rm9200",
587 .driver_data = (unsigned long) &at91rm9200_config,
588 }, {
589 .name = "i2c-at91sam9261",
590 .driver_data = (unsigned long) &at91sam9261_config,
591 }, {
592 .name = "i2c-at91sam9260",
593 .driver_data = (unsigned long) &at91sam9260_config,
594 }, {
595 .name = "i2c-at91sam9g20",
596 .driver_data = (unsigned long) &at91sam9g20_config,
597 }, {
598 .name = "i2c-at91sam9g10",
599 .driver_data = (unsigned long) &at91sam9g10_config,
600 }, {
601 /* sentinel */
602 }
603 };
604
605 #if defined(CONFIG_OF)
606 static struct at91_twi_pdata at91sam9x5_config = {
607 .clk_max_div = 7,
608 .clk_offset = 4,
609 .has_unre_flag = false,
610 };
611
612 static const struct of_device_id atmel_twi_dt_ids[] = {
613 {
614 .compatible = "atmel,at91rm9200-i2c",
615 .data = &at91rm9200_config,
616 } , {
617 .compatible = "atmel,at91sam9260-i2c",
618 .data = &at91sam9260_config,
619 } , {
620 .compatible = "atmel,at91sam9261-i2c",
621 .data = &at91sam9261_config,
622 } , {
623 .compatible = "atmel,at91sam9g20-i2c",
624 .data = &at91sam9g20_config,
625 } , {
626 .compatible = "atmel,at91sam9g10-i2c",
627 .data = &at91sam9g10_config,
628 }, {
629 .compatible = "atmel,at91sam9x5-i2c",
630 .data = &at91sam9x5_config,
631 }, {
632 /* sentinel */
633 }
634 };
635 MODULE_DEVICE_TABLE(of, atmel_twi_dt_ids);
636 #endif
637
638 static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
639 {
640 int ret = 0;
641 struct dma_slave_config slave_config;
642 struct at91_twi_dma *dma = &dev->dma;
643
644 memset(&slave_config, 0, sizeof(slave_config));
645 slave_config.src_addr = (dma_addr_t)phy_addr + AT91_TWI_RHR;
646 slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
647 slave_config.src_maxburst = 1;
648 slave_config.dst_addr = (dma_addr_t)phy_addr + AT91_TWI_THR;
649 slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
650 slave_config.dst_maxburst = 1;
651 slave_config.device_fc = false;
652
653 dma->chan_tx = dma_request_slave_channel_reason(dev->dev, "tx");
654 if (IS_ERR(dma->chan_tx)) {
655 ret = PTR_ERR(dma->chan_tx);
656 dma->chan_tx = NULL;
657 goto error;
658 }
659
660 dma->chan_rx = dma_request_slave_channel_reason(dev->dev, "rx");
661 if (IS_ERR(dma->chan_rx)) {
662 ret = PTR_ERR(dma->chan_rx);
663 dma->chan_rx = NULL;
664 goto error;
665 }
666
667 slave_config.direction = DMA_MEM_TO_DEV;
668 if (dmaengine_slave_config(dma->chan_tx, &slave_config)) {
669 dev_err(dev->dev, "failed to configure tx channel\n");
670 ret = -EINVAL;
671 goto error;
672 }
673
674 slave_config.direction = DMA_DEV_TO_MEM;
675 if (dmaengine_slave_config(dma->chan_rx, &slave_config)) {
676 dev_err(dev->dev, "failed to configure rx channel\n");
677 ret = -EINVAL;
678 goto error;
679 }
680
681 sg_init_table(&dma->sg, 1);
682 dma->buf_mapped = false;
683 dma->xfer_in_progress = false;
684 dev->use_dma = true;
685
686 dev_info(dev->dev, "using %s (tx) and %s (rx) for DMA transfers\n",
687 dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx));
688
689 return ret;
690
691 error:
692 if (ret != -EPROBE_DEFER)
693 dev_info(dev->dev, "can't use DMA, error %d\n", ret);
694 if (dma->chan_rx)
695 dma_release_channel(dma->chan_rx);
696 if (dma->chan_tx)
697 dma_release_channel(dma->chan_tx);
698 return ret;
699 }
700
701 static struct at91_twi_pdata *at91_twi_get_driver_data(
702 struct platform_device *pdev)
703 {
704 if (pdev->dev.of_node) {
705 const struct of_device_id *match;
706 match = of_match_node(atmel_twi_dt_ids, pdev->dev.of_node);
707 if (!match)
708 return NULL;
709 return (struct at91_twi_pdata *)match->data;
710 }
711 return (struct at91_twi_pdata *) platform_get_device_id(pdev)->driver_data;
712 }
713
714 static int at91_twi_probe(struct platform_device *pdev)
715 {
716 struct at91_twi_dev *dev;
717 struct resource *mem;
718 int rc;
719 u32 phy_addr;
720 u32 bus_clk_rate;
721
722 dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
723 if (!dev)
724 return -ENOMEM;
725 init_completion(&dev->cmd_complete);
726 dev->dev = &pdev->dev;
727
728 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
729 if (!mem)
730 return -ENODEV;
731 phy_addr = mem->start;
732
733 dev->pdata = at91_twi_get_driver_data(pdev);
734 if (!dev->pdata)
735 return -ENODEV;
736
737 dev->base = devm_ioremap_resource(&pdev->dev, mem);
738 if (IS_ERR(dev->base))
739 return PTR_ERR(dev->base);
740
741 dev->irq = platform_get_irq(pdev, 0);
742 if (dev->irq < 0)
743 return dev->irq;
744
745 rc = devm_request_irq(&pdev->dev, dev->irq, atmel_twi_interrupt, 0,
746 dev_name(dev->dev), dev);
747 if (rc) {
748 dev_err(dev->dev, "Cannot get irq %d: %d\n", dev->irq, rc);
749 return rc;
750 }
751
752 platform_set_drvdata(pdev, dev);
753
754 dev->clk = devm_clk_get(dev->dev, NULL);
755 if (IS_ERR(dev->clk)) {
756 dev_err(dev->dev, "no clock defined\n");
757 return -ENODEV;
758 }
759 clk_prepare_enable(dev->clk);
760
761 if (dev->dev->of_node) {
762 rc = at91_twi_configure_dma(dev, phy_addr);
763 if (rc == -EPROBE_DEFER)
764 return rc;
765 }
766
767 rc = of_property_read_u32(dev->dev->of_node, "clock-frequency",
768 &bus_clk_rate);
769 if (rc)
770 bus_clk_rate = DEFAULT_TWI_CLK_HZ;
771
772 at91_calc_twi_clock(dev, bus_clk_rate);
773 at91_init_twi_bus(dev);
774
775 snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
776 i2c_set_adapdata(&dev->adapter, dev);
777 dev->adapter.owner = THIS_MODULE;
778 dev->adapter.class = I2C_CLASS_DEPRECATED;
779 dev->adapter.algo = &at91_twi_algorithm;
780 dev->adapter.dev.parent = dev->dev;
781 dev->adapter.nr = pdev->id;
782 dev->adapter.timeout = AT91_I2C_TIMEOUT;
783 dev->adapter.dev.of_node = pdev->dev.of_node;
784
785 pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT);
786 pm_runtime_use_autosuspend(dev->dev);
787 pm_runtime_set_active(dev->dev);
788 pm_runtime_enable(dev->dev);
789
790 rc = i2c_add_numbered_adapter(&dev->adapter);
791 if (rc) {
792 dev_err(dev->dev, "Adapter %s registration failed\n",
793 dev->adapter.name);
794 clk_disable_unprepare(dev->clk);
795
796 pm_runtime_disable(dev->dev);
797 pm_runtime_set_suspended(dev->dev);
798
799 return rc;
800 }
801
802 dev_info(dev->dev, "AT91 i2c bus driver.\n");
803 return 0;
804 }
805
806 static int at91_twi_remove(struct platform_device *pdev)
807 {
808 struct at91_twi_dev *dev = platform_get_drvdata(pdev);
809
810 i2c_del_adapter(&dev->adapter);
811 clk_disable_unprepare(dev->clk);
812
813 pm_runtime_disable(dev->dev);
814 pm_runtime_set_suspended(dev->dev);
815
816 return 0;
817 }
818
819 #ifdef CONFIG_PM
820
821 static int at91_twi_runtime_suspend(struct device *dev)
822 {
823 struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
824
825 clk_disable_unprepare(twi_dev->clk);
826
827 pinctrl_pm_select_sleep_state(dev);
828
829 return 0;
830 }
831
832 static int at91_twi_runtime_resume(struct device *dev)
833 {
834 struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
835
836 pinctrl_pm_select_default_state(dev);
837
838 return clk_prepare_enable(twi_dev->clk);
839 }
840
841 static int at91_twi_suspend_noirq(struct device *dev)
842 {
843 if (!pm_runtime_status_suspended(dev))
844 at91_twi_runtime_suspend(dev);
845
846 return 0;
847 }
848
849 static int at91_twi_resume_noirq(struct device *dev)
850 {
851 int ret;
852
853 if (!pm_runtime_status_suspended(dev)) {
854 ret = at91_twi_runtime_resume(dev);
855 if (ret)
856 return ret;
857 }
858
859 pm_runtime_mark_last_busy(dev);
860 pm_request_autosuspend(dev);
861
862 return 0;
863 }
864
865 static const struct dev_pm_ops at91_twi_pm = {
866 .suspend_noirq = at91_twi_suspend_noirq,
867 .resume_noirq = at91_twi_resume_noirq,
868 .runtime_suspend = at91_twi_runtime_suspend,
869 .runtime_resume = at91_twi_runtime_resume,
870 };
871
872 #define at91_twi_pm_ops (&at91_twi_pm)
873 #else
874 #define at91_twi_pm_ops NULL
875 #endif
876
877 static struct platform_driver at91_twi_driver = {
878 .probe = at91_twi_probe,
879 .remove = at91_twi_remove,
880 .id_table = at91_twi_devtypes,
881 .driver = {
882 .name = "at91_i2c",
883 .of_match_table = of_match_ptr(atmel_twi_dt_ids),
884 .pm = at91_twi_pm_ops,
885 },
886 };
887
888 static int __init at91_twi_init(void)
889 {
890 return platform_driver_register(&at91_twi_driver);
891 }
892
893 static void __exit at91_twi_exit(void)
894 {
895 platform_driver_unregister(&at91_twi_driver);
896 }
897
898 subsys_initcall(at91_twi_init);
899 module_exit(at91_twi_exit);
900
901 MODULE_AUTHOR("Nikolaus Voss <n.voss@weinmann.de>");
902 MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
903 MODULE_LICENSE("GPL");
904 MODULE_ALIAS("platform:at91_i2c");
Linux kernel - Deliverables
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