2 * i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
4 * Copyright (C) 2011 Weinmann Medical GmbH
5 * Author: Nikolaus Voss <n.voss@weinmann.de>
7 * Evolved from original work by:
8 * Copyright (C) 2004 Rick Bronson
9 * Converted to 2.6 by Andrew Victor <andrew@sanpeople.com>
11 * Borrowed heavily from original work by:
12 * Copyright (C) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
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.
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>
28 #include <linux/module.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>
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
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 */
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 */
55 #define AT91_TWI_IADR 0x000c /* Internal Address Register */
57 #define AT91_TWI_CWGR 0x0010 /* Clock Waveform Generator Reg */
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 */
64 #define AT91_TWI_OVRE 0x0040 /* Overrun Error */
65 #define AT91_TWI_UNRE 0x0080 /* Underrun Error */
66 #define AT91_TWI_NACK 0x0100 /* Not Acknowledged */
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 */
74 struct at91_twi_pdata {
78 struct at_dma_slave dma_slave;
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;
88 bool xfer_in_progress;
94 struct completion cmd_complete;
101 unsigned transfer_status;
102 struct i2c_adapter adapter;
103 unsigned twi_cwgr_reg;
104 struct at91_twi_pdata *pdata;
107 struct at91_twi_dma dma;
110 static unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg)
112 return readl_relaxed(dev->base + reg);
115 static void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val)
117 writel_relaxed(val, dev->base + reg);
120 static void at91_disable_twi_interrupts(struct at91_twi_dev *dev)
122 at91_twi_write(dev, AT91_TWI_IDR,
123 AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY);
126 static void at91_twi_irq_save(struct at91_twi_dev *dev)
128 dev->imr = at91_twi_read(dev, AT91_TWI_IMR) & 0x7;
129 at91_disable_twi_interrupts(dev);
132 static void at91_twi_irq_restore(struct at91_twi_dev *dev)
134 at91_twi_write(dev, AT91_TWI_IER, dev->imr);
137 static void at91_init_twi_bus(struct at91_twi_dev *dev)
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);
147 * Calculate symmetric clock as stated in datasheet:
148 * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
150 static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
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;
157 div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
158 2 * twi_clk) - offset);
159 ckdiv = fls(div >> 8);
162 if (ckdiv > max_ckdiv) {
163 dev_warn(dev->dev, "%d exceeds ckdiv max value which is %d.\n",
169 dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv;
170 dev_dbg(dev->dev, "cdiv %d ckdiv %d\n", cdiv, ckdiv);
173 static void at91_twi_dma_cleanup(struct at91_twi_dev *dev)
175 struct at91_twi_dma *dma = &dev->dma;
177 at91_twi_irq_save(dev);
179 if (dma->xfer_in_progress) {
180 if (dma->direction == DMA_FROM_DEVICE)
181 dmaengine_terminate_all(dma->chan_rx);
183 dmaengine_terminate_all(dma->chan_tx);
184 dma->xfer_in_progress = false;
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;
192 at91_twi_irq_restore(dev);
195 static void at91_twi_write_next_byte(struct at91_twi_dev *dev)
197 if (dev->buf_len <= 0)
200 at91_twi_write(dev, AT91_TWI_THR, *dev->buf);
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);
206 dev_dbg(dev->dev, "wrote 0x%x, to go %d\n", *dev->buf, dev->buf_len);
211 static void at91_twi_write_data_dma_callback(void *data)
213 struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
215 dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg),
216 dev->buf_len, DMA_TO_DEVICE);
218 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
221 static void at91_twi_write_data_dma(struct at91_twi_dev *dev)
224 struct dma_async_tx_descriptor *txdesc;
225 struct at91_twi_dma *dma = &dev->dma;
226 struct dma_chan *chan_tx = dma->chan_tx;
228 if (dev->buf_len <= 0)
231 dma->direction = DMA_TO_DEVICE;
233 at91_twi_irq_save(dev);
234 dma_addr = dma_map_single(dev->dev, dev->buf, dev->buf_len,
236 if (dma_mapping_error(dev->dev, dma_addr)) {
237 dev_err(dev->dev, "dma map failed\n");
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;
245 txdesc = dmaengine_prep_slave_sg(chan_tx, &dma->sg, 1, DMA_MEM_TO_DEV,
246 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
248 dev_err(dev->dev, "dma prep slave sg failed\n");
252 txdesc->callback = at91_twi_write_data_dma_callback;
253 txdesc->callback_param = dev;
255 dma->xfer_in_progress = true;
256 dmaengine_submit(txdesc);
257 dma_async_issue_pending(chan_tx);
262 at91_twi_dma_cleanup(dev);
265 static void at91_twi_read_next_byte(struct at91_twi_dev *dev)
267 if (dev->buf_len <= 0)
270 *dev->buf = at91_twi_read(dev, AT91_TWI_RHR) & 0xff;
273 /* return if aborting, we only needed to read RHR to clear RXRDY*/
274 if (dev->recv_len_abort)
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",
287 /* abort and send the stop by reading one more byte */
288 dev->recv_len_abort = true;
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);
297 dev_dbg(dev->dev, "read 0x%x, to go %d\n", *dev->buf, dev->buf_len);
302 static void at91_twi_read_data_dma_callback(void *data)
304 struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
306 dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg),
307 dev->buf_len, DMA_FROM_DEVICE);
309 /* The last two bytes have to be read without using dma */
310 dev->buf += dev->buf_len - 2;
312 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_RXRDY);
315 static void at91_twi_read_data_dma(struct at91_twi_dev *dev)
318 struct dma_async_tx_descriptor *rxdesc;
319 struct at91_twi_dma *dma = &dev->dma;
320 struct dma_chan *chan_rx = dma->chan_rx;
322 dma->direction = DMA_FROM_DEVICE;
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,
328 if (dma_mapping_error(dev->dev, dma_addr)) {
329 dev_err(dev->dev, "dma map failed\n");
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;
337 rxdesc = dmaengine_prep_slave_sg(chan_rx, &dma->sg, 1, DMA_DEV_TO_MEM,
338 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
340 dev_err(dev->dev, "dma prep slave sg failed\n");
344 rxdesc->callback = at91_twi_read_data_dma_callback;
345 rxdesc->callback_param = dev;
347 dma->xfer_in_progress = true;
348 dmaengine_submit(rxdesc);
349 dma_async_issue_pending(dma->chan_rx);
354 at91_twi_dma_cleanup(dev);
357 static irqreturn_t atmel_twi_interrupt(int irq, void *dev_id)
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);
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);
370 /* catch error flags */
371 dev->transfer_status |= status;
373 if (irqstatus & AT91_TWI_TXCOMP) {
374 at91_disable_twi_interrupts(dev);
375 complete(&dev->cmd_complete);
381 static int at91_do_twi_transfer(struct at91_twi_dev *dev)
384 unsigned long time_left;
385 bool has_unre_flag = dev->pdata->has_unre_flag;
387 dev_dbg(dev->dev, "transfer: %s %d bytes.\n",
388 (dev->msg->flags & I2C_M_RD) ? "read" : "write", dev->buf_len);
390 reinit_completion(&dev->cmd_complete);
391 dev->transfer_status = 0;
394 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_QUICK);
395 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
396 } else if (dev->msg->flags & I2C_M_RD) {
397 unsigned start_flags = AT91_TWI_START;
399 if (at91_twi_read(dev, AT91_TWI_SR) & AT91_TWI_RXRDY) {
400 dev_err(dev->dev, "RXRDY still set!");
401 at91_twi_read(dev, AT91_TWI_RHR);
404 /* if only one byte is to be read, immediately stop transfer */
405 if (dev->buf_len <= 1 && !(dev->msg->flags & I2C_M_RECV_LEN))
406 start_flags |= AT91_TWI_STOP;
407 at91_twi_write(dev, AT91_TWI_CR, start_flags);
409 * When using dma, the last byte has to be read manually in
410 * order to not send the stop command too late and then
411 * to receive extra data. In practice, there are some issues
412 * if you use the dma to read n-1 bytes because of latency.
413 * Reading n-2 bytes with dma and the two last ones manually
414 * seems to be the best solution.
416 if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) {
417 at91_twi_read_data_dma(dev);
419 * It is important to enable TXCOMP irq here because
420 * doing it only when transferring the last two bytes
421 * will mask NACK errors since TXCOMP is set when a
424 at91_twi_write(dev, AT91_TWI_IER,
427 at91_twi_write(dev, AT91_TWI_IER,
428 AT91_TWI_TXCOMP | AT91_TWI_RXRDY);
430 if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) {
431 at91_twi_write_data_dma(dev);
432 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
434 at91_twi_write_next_byte(dev);
435 at91_twi_write(dev, AT91_TWI_IER,
436 AT91_TWI_TXCOMP | AT91_TWI_TXRDY);
440 time_left = wait_for_completion_timeout(&dev->cmd_complete,
441 dev->adapter.timeout);
442 if (time_left == 0) {
443 dev_err(dev->dev, "controller timed out\n");
444 at91_init_twi_bus(dev);
448 if (dev->transfer_status & AT91_TWI_NACK) {
449 dev_dbg(dev->dev, "received nack\n");
453 if (dev->transfer_status & AT91_TWI_OVRE) {
454 dev_err(dev->dev, "overrun while reading\n");
458 if (has_unre_flag && dev->transfer_status & AT91_TWI_UNRE) {
459 dev_err(dev->dev, "underrun while writing\n");
463 if (dev->recv_len_abort) {
464 dev_err(dev->dev, "invalid smbus block length recvd\n");
469 dev_dbg(dev->dev, "transfer complete\n");
474 at91_twi_dma_cleanup(dev);
478 static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
480 struct at91_twi_dev *dev = i2c_get_adapdata(adap);
482 unsigned int_addr_flag = 0;
483 struct i2c_msg *m_start = msg;
485 dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
487 ret = pm_runtime_get_sync(dev->dev);
492 int internal_address = 0;
495 /* 1st msg is put into the internal address, start with 2nd */
497 for (i = 0; i < msg->len; ++i) {
498 const unsigned addr = msg->buf[msg->len - 1 - i];
500 internal_address |= addr << (8 * i);
501 int_addr_flag += AT91_TWI_IADRSZ_1;
503 at91_twi_write(dev, AT91_TWI_IADR, internal_address);
506 at91_twi_write(dev, AT91_TWI_MMR, (m_start->addr << 16) | int_addr_flag
507 | ((m_start->flags & I2C_M_RD) ? AT91_TWI_MREAD : 0));
509 dev->buf_len = m_start->len;
510 dev->buf = m_start->buf;
512 dev->recv_len_abort = false;
514 ret = at91_do_twi_transfer(dev);
516 ret = (ret < 0) ? ret : num;
518 pm_runtime_mark_last_busy(dev->dev);
519 pm_runtime_put_autosuspend(dev->dev);
525 * The hardware can handle at most two messages concatenated by a
526 * repeated start via it's internal address feature.
528 static struct i2c_adapter_quirks at91_twi_quirks = {
529 .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | I2C_AQ_COMB_SAME_ADDR,
530 .max_comb_1st_msg_len = 3,
533 static u32 at91_twi_func(struct i2c_adapter *adapter)
535 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
536 | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
539 static struct i2c_algorithm at91_twi_algorithm = {
540 .master_xfer = at91_twi_xfer,
541 .functionality = at91_twi_func,
544 static struct at91_twi_pdata at91rm9200_config = {
547 .has_unre_flag = true,
550 static struct at91_twi_pdata at91sam9261_config = {
553 .has_unre_flag = false,
556 static struct at91_twi_pdata at91sam9260_config = {
559 .has_unre_flag = false,
562 static struct at91_twi_pdata at91sam9g20_config = {
565 .has_unre_flag = false,
568 static struct at91_twi_pdata at91sam9g10_config = {
571 .has_unre_flag = false,
574 static const struct platform_device_id at91_twi_devtypes[] = {
576 .name = "i2c-at91rm9200",
577 .driver_data = (unsigned long) &at91rm9200_config,
579 .name = "i2c-at91sam9261",
580 .driver_data = (unsigned long) &at91sam9261_config,
582 .name = "i2c-at91sam9260",
583 .driver_data = (unsigned long) &at91sam9260_config,
585 .name = "i2c-at91sam9g20",
586 .driver_data = (unsigned long) &at91sam9g20_config,
588 .name = "i2c-at91sam9g10",
589 .driver_data = (unsigned long) &at91sam9g10_config,
595 #if defined(CONFIG_OF)
596 static struct at91_twi_pdata at91sam9x5_config = {
599 .has_unre_flag = false,
602 static const struct of_device_id atmel_twi_dt_ids[] = {
604 .compatible = "atmel,at91rm9200-i2c",
605 .data = &at91rm9200_config,
607 .compatible = "atmel,at91sam9260-i2c",
608 .data = &at91sam9260_config,
610 .compatible = "atmel,at91sam9261-i2c",
611 .data = &at91sam9261_config,
613 .compatible = "atmel,at91sam9g20-i2c",
614 .data = &at91sam9g20_config,
616 .compatible = "atmel,at91sam9g10-i2c",
617 .data = &at91sam9g10_config,
619 .compatible = "atmel,at91sam9x5-i2c",
620 .data = &at91sam9x5_config,
625 MODULE_DEVICE_TABLE(of, atmel_twi_dt_ids);
628 static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
631 struct dma_slave_config slave_config;
632 struct at91_twi_dma *dma = &dev->dma;
634 memset(&slave_config, 0, sizeof(slave_config));
635 slave_config.src_addr = (dma_addr_t)phy_addr + AT91_TWI_RHR;
636 slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
637 slave_config.src_maxburst = 1;
638 slave_config.dst_addr = (dma_addr_t)phy_addr + AT91_TWI_THR;
639 slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
640 slave_config.dst_maxburst = 1;
641 slave_config.device_fc = false;
643 dma->chan_tx = dma_request_slave_channel_reason(dev->dev, "tx");
644 if (IS_ERR(dma->chan_tx)) {
645 ret = PTR_ERR(dma->chan_tx);
650 dma->chan_rx = dma_request_slave_channel_reason(dev->dev, "rx");
651 if (IS_ERR(dma->chan_rx)) {
652 ret = PTR_ERR(dma->chan_rx);
657 slave_config.direction = DMA_MEM_TO_DEV;
658 if (dmaengine_slave_config(dma->chan_tx, &slave_config)) {
659 dev_err(dev->dev, "failed to configure tx channel\n");
664 slave_config.direction = DMA_DEV_TO_MEM;
665 if (dmaengine_slave_config(dma->chan_rx, &slave_config)) {
666 dev_err(dev->dev, "failed to configure rx channel\n");
671 sg_init_table(&dma->sg, 1);
672 dma->buf_mapped = false;
673 dma->xfer_in_progress = false;
676 dev_info(dev->dev, "using %s (tx) and %s (rx) for DMA transfers\n",
677 dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx));
682 if (ret != -EPROBE_DEFER)
683 dev_info(dev->dev, "can't use DMA, error %d\n", ret);
685 dma_release_channel(dma->chan_rx);
687 dma_release_channel(dma->chan_tx);
691 static struct at91_twi_pdata *at91_twi_get_driver_data(
692 struct platform_device *pdev)
694 if (pdev->dev.of_node) {
695 const struct of_device_id *match;
696 match = of_match_node(atmel_twi_dt_ids, pdev->dev.of_node);
699 return (struct at91_twi_pdata *)match->data;
701 return (struct at91_twi_pdata *) platform_get_device_id(pdev)->driver_data;
704 static int at91_twi_probe(struct platform_device *pdev)
706 struct at91_twi_dev *dev;
707 struct resource *mem;
712 dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
715 init_completion(&dev->cmd_complete);
716 dev->dev = &pdev->dev;
718 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
721 phy_addr = mem->start;
723 dev->pdata = at91_twi_get_driver_data(pdev);
727 dev->base = devm_ioremap_resource(&pdev->dev, mem);
728 if (IS_ERR(dev->base))
729 return PTR_ERR(dev->base);
731 dev->irq = platform_get_irq(pdev, 0);
735 rc = devm_request_irq(&pdev->dev, dev->irq, atmel_twi_interrupt, 0,
736 dev_name(dev->dev), dev);
738 dev_err(dev->dev, "Cannot get irq %d: %d\n", dev->irq, rc);
742 platform_set_drvdata(pdev, dev);
744 dev->clk = devm_clk_get(dev->dev, NULL);
745 if (IS_ERR(dev->clk)) {
746 dev_err(dev->dev, "no clock defined\n");
749 clk_prepare_enable(dev->clk);
751 if (dev->dev->of_node) {
752 rc = at91_twi_configure_dma(dev, phy_addr);
753 if (rc == -EPROBE_DEFER)
757 rc = of_property_read_u32(dev->dev->of_node, "clock-frequency",
760 bus_clk_rate = DEFAULT_TWI_CLK_HZ;
762 at91_calc_twi_clock(dev, bus_clk_rate);
763 at91_init_twi_bus(dev);
765 snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
766 i2c_set_adapdata(&dev->adapter, dev);
767 dev->adapter.owner = THIS_MODULE;
768 dev->adapter.class = I2C_CLASS_DEPRECATED;
769 dev->adapter.algo = &at91_twi_algorithm;
770 dev->adapter.quirks = &at91_twi_quirks;
771 dev->adapter.dev.parent = dev->dev;
772 dev->adapter.nr = pdev->id;
773 dev->adapter.timeout = AT91_I2C_TIMEOUT;
774 dev->adapter.dev.of_node = pdev->dev.of_node;
776 pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT);
777 pm_runtime_use_autosuspend(dev->dev);
778 pm_runtime_set_active(dev->dev);
779 pm_runtime_enable(dev->dev);
781 rc = i2c_add_numbered_adapter(&dev->adapter);
783 dev_err(dev->dev, "Adapter %s registration failed\n",
785 clk_disable_unprepare(dev->clk);
787 pm_runtime_disable(dev->dev);
788 pm_runtime_set_suspended(dev->dev);
793 dev_info(dev->dev, "AT91 i2c bus driver.\n");
797 static int at91_twi_remove(struct platform_device *pdev)
799 struct at91_twi_dev *dev = platform_get_drvdata(pdev);
801 i2c_del_adapter(&dev->adapter);
802 clk_disable_unprepare(dev->clk);
804 pm_runtime_disable(dev->dev);
805 pm_runtime_set_suspended(dev->dev);
812 static int at91_twi_runtime_suspend(struct device *dev)
814 struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
816 clk_disable_unprepare(twi_dev->clk);
818 pinctrl_pm_select_sleep_state(dev);
823 static int at91_twi_runtime_resume(struct device *dev)
825 struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
827 pinctrl_pm_select_default_state(dev);
829 return clk_prepare_enable(twi_dev->clk);
832 static int at91_twi_suspend_noirq(struct device *dev)
834 if (!pm_runtime_status_suspended(dev))
835 at91_twi_runtime_suspend(dev);
840 static int at91_twi_resume_noirq(struct device *dev)
844 if (!pm_runtime_status_suspended(dev)) {
845 ret = at91_twi_runtime_resume(dev);
850 pm_runtime_mark_last_busy(dev);
851 pm_request_autosuspend(dev);
856 static const struct dev_pm_ops at91_twi_pm = {
857 .suspend_noirq = at91_twi_suspend_noirq,
858 .resume_noirq = at91_twi_resume_noirq,
859 .runtime_suspend = at91_twi_runtime_suspend,
860 .runtime_resume = at91_twi_runtime_resume,
863 #define at91_twi_pm_ops (&at91_twi_pm)
865 #define at91_twi_pm_ops NULL
868 static struct platform_driver at91_twi_driver = {
869 .probe = at91_twi_probe,
870 .remove = at91_twi_remove,
871 .id_table = at91_twi_devtypes,
874 .of_match_table = of_match_ptr(atmel_twi_dt_ids),
875 .pm = at91_twi_pm_ops,
879 static int __init at91_twi_init(void)
881 return platform_driver_register(&at91_twi_driver);
884 static void __exit at91_twi_exit(void)
886 platform_driver_unregister(&at91_twi_driver);
889 subsys_initcall(at91_twi_init);
890 module_exit(at91_twi_exit);
892 MODULE_AUTHOR("Nikolaus Voss <n.voss@weinmann.de>");
893 MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
894 MODULE_LICENSE("GPL");
895 MODULE_ALIAS("platform:at91_i2c");