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>
35 #define DEFAULT_TWI_CLK_HZ 100000 /* max 400 Kbits/s */
36 #define AT91_I2C_TIMEOUT msecs_to_jiffies(100) /* transfer timeout */
37 #define AT91_I2C_DMA_THRESHOLD 8 /* enable DMA if transfer size is bigger than this threshold */
39 /* AT91 TWI register definitions */
40 #define AT91_TWI_CR 0x0000 /* Control Register */
41 #define AT91_TWI_START 0x0001 /* Send a Start Condition */
42 #define AT91_TWI_STOP 0x0002 /* Send a Stop Condition */
43 #define AT91_TWI_MSEN 0x0004 /* Master Transfer Enable */
44 #define AT91_TWI_SVDIS 0x0020 /* Slave Transfer Disable */
45 #define AT91_TWI_QUICK 0x0040 /* SMBus quick command */
46 #define AT91_TWI_SWRST 0x0080 /* Software Reset */
48 #define AT91_TWI_MMR 0x0004 /* Master Mode Register */
49 #define AT91_TWI_IADRSZ_1 0x0100 /* Internal Device Address Size */
50 #define AT91_TWI_MREAD 0x1000 /* Master Read Direction */
52 #define AT91_TWI_IADR 0x000c /* Internal Address Register */
54 #define AT91_TWI_CWGR 0x0010 /* Clock Waveform Generator Reg */
56 #define AT91_TWI_SR 0x0020 /* Status Register */
57 #define AT91_TWI_TXCOMP 0x0001 /* Transmission Complete */
58 #define AT91_TWI_RXRDY 0x0002 /* Receive Holding Register Ready */
59 #define AT91_TWI_TXRDY 0x0004 /* Transmit Holding Register Ready */
61 #define AT91_TWI_OVRE 0x0040 /* Overrun Error */
62 #define AT91_TWI_UNRE 0x0080 /* Underrun Error */
63 #define AT91_TWI_NACK 0x0100 /* Not Acknowledged */
65 #define AT91_TWI_IER 0x0024 /* Interrupt Enable Register */
66 #define AT91_TWI_IDR 0x0028 /* Interrupt Disable Register */
67 #define AT91_TWI_IMR 0x002c /* Interrupt Mask Register */
68 #define AT91_TWI_RHR 0x0030 /* Receive Holding Register */
69 #define AT91_TWI_THR 0x0034 /* Transmit Holding Register */
71 struct at91_twi_pdata {
76 struct at_dma_slave dma_slave;
80 struct dma_chan *chan_rx;
81 struct dma_chan *chan_tx;
82 struct scatterlist sg;
83 struct dma_async_tx_descriptor *data_desc;
84 enum dma_data_direction direction;
86 bool xfer_in_progress;
92 struct completion cmd_complete;
99 unsigned transfer_status;
100 struct i2c_adapter adapter;
101 unsigned twi_cwgr_reg;
102 struct at91_twi_pdata *pdata;
105 struct at91_twi_dma dma;
108 static unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg)
110 return readl_relaxed(dev->base + reg);
113 static void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val)
115 writel_relaxed(val, dev->base + reg);
118 static void at91_disable_twi_interrupts(struct at91_twi_dev *dev)
120 at91_twi_write(dev, AT91_TWI_IDR,
121 AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY);
124 static void at91_twi_irq_save(struct at91_twi_dev *dev)
126 dev->imr = at91_twi_read(dev, AT91_TWI_IMR) & 0x7;
127 at91_disable_twi_interrupts(dev);
130 static void at91_twi_irq_restore(struct at91_twi_dev *dev)
132 at91_twi_write(dev, AT91_TWI_IER, dev->imr);
135 static void at91_init_twi_bus(struct at91_twi_dev *dev)
137 at91_disable_twi_interrupts(dev);
138 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST);
139 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_MSEN);
140 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SVDIS);
141 at91_twi_write(dev, AT91_TWI_CWGR, dev->twi_cwgr_reg);
145 * Calculate symmetric clock as stated in datasheet:
146 * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
148 static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
150 int ckdiv, cdiv, div;
151 struct at91_twi_pdata *pdata = dev->pdata;
152 int offset = pdata->clk_offset;
153 int max_ckdiv = pdata->clk_max_div;
155 div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
156 2 * twi_clk) - offset);
157 ckdiv = fls(div >> 8);
160 if (ckdiv > max_ckdiv) {
161 dev_warn(dev->dev, "%d exceeds ckdiv max value which is %d.\n",
167 dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv;
168 dev_dbg(dev->dev, "cdiv %d ckdiv %d\n", cdiv, ckdiv);
171 static void at91_twi_dma_cleanup(struct at91_twi_dev *dev)
173 struct at91_twi_dma *dma = &dev->dma;
175 at91_twi_irq_save(dev);
177 if (dma->xfer_in_progress) {
178 if (dma->direction == DMA_FROM_DEVICE)
179 dmaengine_terminate_all(dma->chan_rx);
181 dmaengine_terminate_all(dma->chan_tx);
182 dma->xfer_in_progress = false;
184 if (dma->buf_mapped) {
185 dma_unmap_single(dev->dev, sg_dma_address(&dma->sg),
186 dev->buf_len, dma->direction);
187 dma->buf_mapped = false;
190 at91_twi_irq_restore(dev);
193 static void at91_twi_write_next_byte(struct at91_twi_dev *dev)
195 if (dev->buf_len <= 0)
198 at91_twi_write(dev, AT91_TWI_THR, *dev->buf);
200 /* send stop when last byte has been written */
201 if (--dev->buf_len == 0)
202 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
204 dev_dbg(dev->dev, "wrote 0x%x, to go %d\n", *dev->buf, dev->buf_len);
209 static void at91_twi_write_data_dma_callback(void *data)
211 struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
213 dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg),
214 dev->buf_len, DMA_TO_DEVICE);
216 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
219 static void at91_twi_write_data_dma(struct at91_twi_dev *dev)
222 struct dma_async_tx_descriptor *txdesc;
223 struct at91_twi_dma *dma = &dev->dma;
224 struct dma_chan *chan_tx = dma->chan_tx;
226 if (dev->buf_len <= 0)
229 dma->direction = DMA_TO_DEVICE;
231 at91_twi_irq_save(dev);
232 dma_addr = dma_map_single(dev->dev, dev->buf, dev->buf_len,
234 if (dma_mapping_error(dev->dev, dma_addr)) {
235 dev_err(dev->dev, "dma map failed\n");
238 dma->buf_mapped = true;
239 at91_twi_irq_restore(dev);
240 sg_dma_len(&dma->sg) = dev->buf_len;
241 sg_dma_address(&dma->sg) = dma_addr;
243 txdesc = dmaengine_prep_slave_sg(chan_tx, &dma->sg, 1, DMA_MEM_TO_DEV,
244 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
246 dev_err(dev->dev, "dma prep slave sg failed\n");
250 txdesc->callback = at91_twi_write_data_dma_callback;
251 txdesc->callback_param = dev;
253 dma->xfer_in_progress = true;
254 dmaengine_submit(txdesc);
255 dma_async_issue_pending(chan_tx);
260 at91_twi_dma_cleanup(dev);
263 static void at91_twi_read_next_byte(struct at91_twi_dev *dev)
265 if (dev->buf_len <= 0)
268 *dev->buf = at91_twi_read(dev, AT91_TWI_RHR) & 0xff;
271 /* return if aborting, we only needed to read RHR to clear RXRDY*/
272 if (dev->recv_len_abort)
275 /* handle I2C_SMBUS_BLOCK_DATA */
276 if (unlikely(dev->msg->flags & I2C_M_RECV_LEN)) {
277 /* ensure length byte is a valid value */
278 if (*dev->buf <= I2C_SMBUS_BLOCK_MAX && *dev->buf > 0) {
279 dev->msg->flags &= ~I2C_M_RECV_LEN;
280 dev->buf_len += *dev->buf;
281 dev->msg->len = dev->buf_len + 1;
282 dev_dbg(dev->dev, "received block length %d\n",
285 /* abort and send the stop by reading one more byte */
286 dev->recv_len_abort = true;
291 /* send stop if second but last byte has been read */
292 if (dev->buf_len == 1)
293 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
295 dev_dbg(dev->dev, "read 0x%x, to go %d\n", *dev->buf, dev->buf_len);
300 static void at91_twi_read_data_dma_callback(void *data)
302 struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
304 dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg),
305 dev->buf_len, DMA_FROM_DEVICE);
307 /* The last two bytes have to be read without using dma */
308 dev->buf += dev->buf_len - 2;
310 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_RXRDY);
313 static void at91_twi_read_data_dma(struct at91_twi_dev *dev)
316 struct dma_async_tx_descriptor *rxdesc;
317 struct at91_twi_dma *dma = &dev->dma;
318 struct dma_chan *chan_rx = dma->chan_rx;
320 dma->direction = DMA_FROM_DEVICE;
322 /* Keep in mind that we won't use dma to read the last two bytes */
323 at91_twi_irq_save(dev);
324 dma_addr = dma_map_single(dev->dev, dev->buf, dev->buf_len - 2,
326 if (dma_mapping_error(dev->dev, dma_addr)) {
327 dev_err(dev->dev, "dma map failed\n");
330 dma->buf_mapped = true;
331 at91_twi_irq_restore(dev);
332 dma->sg.dma_address = dma_addr;
333 sg_dma_len(&dma->sg) = dev->buf_len - 2;
335 rxdesc = dmaengine_prep_slave_sg(chan_rx, &dma->sg, 1, DMA_DEV_TO_MEM,
336 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
338 dev_err(dev->dev, "dma prep slave sg failed\n");
342 rxdesc->callback = at91_twi_read_data_dma_callback;
343 rxdesc->callback_param = dev;
345 dma->xfer_in_progress = true;
346 dmaengine_submit(rxdesc);
347 dma_async_issue_pending(dma->chan_rx);
352 at91_twi_dma_cleanup(dev);
355 static irqreturn_t atmel_twi_interrupt(int irq, void *dev_id)
357 struct at91_twi_dev *dev = dev_id;
358 const unsigned status = at91_twi_read(dev, AT91_TWI_SR);
359 const unsigned irqstatus = status & at91_twi_read(dev, AT91_TWI_IMR);
363 else if (irqstatus & AT91_TWI_RXRDY)
364 at91_twi_read_next_byte(dev);
365 else if (irqstatus & AT91_TWI_TXRDY)
366 at91_twi_write_next_byte(dev);
368 /* catch error flags */
369 dev->transfer_status |= status;
371 if (irqstatus & AT91_TWI_TXCOMP) {
372 at91_disable_twi_interrupts(dev);
373 complete(&dev->cmd_complete);
379 static int at91_do_twi_transfer(struct at91_twi_dev *dev)
382 bool has_unre_flag = dev->pdata->has_unre_flag;
384 dev_dbg(dev->dev, "transfer: %s %d bytes.\n",
385 (dev->msg->flags & I2C_M_RD) ? "read" : "write", dev->buf_len);
387 reinit_completion(&dev->cmd_complete);
388 dev->transfer_status = 0;
391 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_QUICK);
392 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
393 } else if (dev->msg->flags & I2C_M_RD) {
394 unsigned start_flags = AT91_TWI_START;
396 if (at91_twi_read(dev, AT91_TWI_SR) & AT91_TWI_RXRDY) {
397 dev_err(dev->dev, "RXRDY still set!");
398 at91_twi_read(dev, AT91_TWI_RHR);
401 /* if only one byte is to be read, immediately stop transfer */
402 if (dev->buf_len <= 1 && !(dev->msg->flags & I2C_M_RECV_LEN))
403 start_flags |= AT91_TWI_STOP;
404 at91_twi_write(dev, AT91_TWI_CR, start_flags);
406 * When using dma, the last byte has to be read manually in
407 * order to not send the stop command too late and then
408 * to receive extra data. In practice, there are some issues
409 * if you use the dma to read n-1 bytes because of latency.
410 * Reading n-2 bytes with dma and the two last ones manually
411 * seems to be the best solution.
413 if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) {
414 at91_twi_read_data_dma(dev);
416 * It is important to enable TXCOMP irq here because
417 * doing it only when transferring the last two bytes
418 * will mask NACK errors since TXCOMP is set when a
421 at91_twi_write(dev, AT91_TWI_IER,
424 at91_twi_write(dev, AT91_TWI_IER,
425 AT91_TWI_TXCOMP | AT91_TWI_RXRDY);
427 if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) {
428 at91_twi_write_data_dma(dev);
429 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
431 at91_twi_write_next_byte(dev);
432 at91_twi_write(dev, AT91_TWI_IER,
433 AT91_TWI_TXCOMP | AT91_TWI_TXRDY);
437 ret = wait_for_completion_io_timeout(&dev->cmd_complete,
438 dev->adapter.timeout);
440 dev_err(dev->dev, "controller timed out\n");
441 at91_init_twi_bus(dev);
445 if (dev->transfer_status & AT91_TWI_NACK) {
446 dev_dbg(dev->dev, "received nack\n");
450 if (dev->transfer_status & AT91_TWI_OVRE) {
451 dev_err(dev->dev, "overrun while reading\n");
455 if (has_unre_flag && dev->transfer_status & AT91_TWI_UNRE) {
456 dev_err(dev->dev, "underrun while writing\n");
460 if (dev->recv_len_abort) {
461 dev_err(dev->dev, "invalid smbus block length recvd\n");
466 dev_dbg(dev->dev, "transfer complete\n");
471 at91_twi_dma_cleanup(dev);
475 static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
477 struct at91_twi_dev *dev = i2c_get_adapdata(adap);
479 unsigned int_addr_flag = 0;
480 struct i2c_msg *m_start = msg;
482 dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
485 * The hardware can handle at most two messages concatenated by a
486 * repeated start via it's internal address feature.
490 "cannot handle more than two concatenated messages.\n");
492 } else if (num == 2) {
493 int internal_address = 0;
496 if (msg->flags & I2C_M_RD) {
497 dev_err(dev->dev, "first transfer must be write.\n");
501 dev_err(dev->dev, "first message size must be <= 3.\n");
505 /* 1st msg is put into the internal address, start with 2nd */
507 for (i = 0; i < msg->len; ++i) {
508 const unsigned addr = msg->buf[msg->len - 1 - i];
510 internal_address |= addr << (8 * i);
511 int_addr_flag += AT91_TWI_IADRSZ_1;
513 at91_twi_write(dev, AT91_TWI_IADR, internal_address);
516 at91_twi_write(dev, AT91_TWI_MMR, (m_start->addr << 16) | int_addr_flag
517 | ((m_start->flags & I2C_M_RD) ? AT91_TWI_MREAD : 0));
519 dev->buf_len = m_start->len;
520 dev->buf = m_start->buf;
522 dev->recv_len_abort = false;
524 ret = at91_do_twi_transfer(dev);
526 return (ret < 0) ? ret : num;
529 static u32 at91_twi_func(struct i2c_adapter *adapter)
531 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
532 | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
535 static struct i2c_algorithm at91_twi_algorithm = {
536 .master_xfer = at91_twi_xfer,
537 .functionality = at91_twi_func,
540 static struct at91_twi_pdata at91rm9200_config = {
543 .has_unre_flag = true,
544 .has_dma_support = false,
547 static struct at91_twi_pdata at91sam9261_config = {
550 .has_unre_flag = false,
551 .has_dma_support = false,
554 static struct at91_twi_pdata at91sam9260_config = {
557 .has_unre_flag = false,
558 .has_dma_support = false,
561 static struct at91_twi_pdata at91sam9g20_config = {
564 .has_unre_flag = false,
565 .has_dma_support = false,
568 static struct at91_twi_pdata at91sam9g10_config = {
571 .has_unre_flag = false,
572 .has_dma_support = false,
575 static const struct platform_device_id at91_twi_devtypes[] = {
577 .name = "i2c-at91rm9200",
578 .driver_data = (unsigned long) &at91rm9200_config,
580 .name = "i2c-at91sam9261",
581 .driver_data = (unsigned long) &at91sam9261_config,
583 .name = "i2c-at91sam9260",
584 .driver_data = (unsigned long) &at91sam9260_config,
586 .name = "i2c-at91sam9g20",
587 .driver_data = (unsigned long) &at91sam9g20_config,
589 .name = "i2c-at91sam9g10",
590 .driver_data = (unsigned long) &at91sam9g10_config,
596 #if defined(CONFIG_OF)
597 static struct at91_twi_pdata at91sam9x5_config = {
600 .has_unre_flag = false,
601 .has_dma_support = true,
604 static const struct of_device_id atmel_twi_dt_ids[] = {
606 .compatible = "atmel,at91rm9200-i2c",
607 .data = &at91rm9200_config,
609 .compatible = "atmel,at91sam9260-i2c",
610 .data = &at91sam9260_config,
612 .compatible = "atmel,at91sam9261-i2c",
613 .data = &at91sam9261_config,
615 .compatible = "atmel,at91sam9g20-i2c",
616 .data = &at91sam9g20_config,
618 .compatible = "atmel,at91sam9g10-i2c",
619 .data = &at91sam9g10_config,
621 .compatible = "atmel,at91sam9x5-i2c",
622 .data = &at91sam9x5_config,
627 MODULE_DEVICE_TABLE(of, atmel_twi_dt_ids);
630 static bool filter(struct dma_chan *chan, void *pdata)
632 struct at91_twi_pdata *sl_pdata = pdata;
633 struct at_dma_slave *sl;
638 sl = &sl_pdata->dma_slave;
639 if (sl && (sl->dma_dev == chan->device->dev)) {
647 static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
650 struct at91_twi_pdata *pdata = dev->pdata;
651 struct dma_slave_config slave_config;
652 struct at91_twi_dma *dma = &dev->dma;
655 memset(&slave_config, 0, sizeof(slave_config));
656 slave_config.src_addr = (dma_addr_t)phy_addr + AT91_TWI_RHR;
657 slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
658 slave_config.src_maxburst = 1;
659 slave_config.dst_addr = (dma_addr_t)phy_addr + AT91_TWI_THR;
660 slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
661 slave_config.dst_maxburst = 1;
662 slave_config.device_fc = false;
665 dma_cap_set(DMA_SLAVE, mask);
667 dma->chan_tx = dma_request_slave_channel_compat(mask, filter, pdata,
670 dev_err(dev->dev, "can't get a DMA channel for tx\n");
675 dma->chan_rx = dma_request_slave_channel_compat(mask, filter, pdata,
678 dev_err(dev->dev, "can't get a DMA channel for rx\n");
683 slave_config.direction = DMA_MEM_TO_DEV;
684 if (dmaengine_slave_config(dma->chan_tx, &slave_config)) {
685 dev_err(dev->dev, "failed to configure tx channel\n");
690 slave_config.direction = DMA_DEV_TO_MEM;
691 if (dmaengine_slave_config(dma->chan_rx, &slave_config)) {
692 dev_err(dev->dev, "failed to configure rx channel\n");
697 sg_init_table(&dma->sg, 1);
698 dma->buf_mapped = false;
699 dma->xfer_in_progress = false;
701 dev_info(dev->dev, "using %s (tx) and %s (rx) for DMA transfers\n",
702 dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx));
707 dev_info(dev->dev, "can't use DMA\n");
709 dma_release_channel(dma->chan_rx);
711 dma_release_channel(dma->chan_tx);
715 static struct at91_twi_pdata *at91_twi_get_driver_data(
716 struct platform_device *pdev)
718 if (pdev->dev.of_node) {
719 const struct of_device_id *match;
720 match = of_match_node(atmel_twi_dt_ids, pdev->dev.of_node);
723 return (struct at91_twi_pdata *)match->data;
725 return (struct at91_twi_pdata *) platform_get_device_id(pdev)->driver_data;
728 static int at91_twi_probe(struct platform_device *pdev)
730 struct at91_twi_dev *dev;
731 struct resource *mem;
736 dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
739 init_completion(&dev->cmd_complete);
740 dev->dev = &pdev->dev;
742 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
745 phy_addr = mem->start;
747 dev->pdata = at91_twi_get_driver_data(pdev);
751 dev->base = devm_ioremap_resource(&pdev->dev, mem);
752 if (IS_ERR(dev->base))
753 return PTR_ERR(dev->base);
755 dev->irq = platform_get_irq(pdev, 0);
759 rc = devm_request_irq(&pdev->dev, dev->irq, atmel_twi_interrupt, 0,
760 dev_name(dev->dev), dev);
762 dev_err(dev->dev, "Cannot get irq %d: %d\n", dev->irq, rc);
766 platform_set_drvdata(pdev, dev);
768 dev->clk = devm_clk_get(dev->dev, NULL);
769 if (IS_ERR(dev->clk)) {
770 dev_err(dev->dev, "no clock defined\n");
773 clk_prepare_enable(dev->clk);
775 if (dev->pdata->has_dma_support) {
776 if (at91_twi_configure_dma(dev, phy_addr) == 0)
780 rc = of_property_read_u32(dev->dev->of_node, "clock-frequency",
783 bus_clk_rate = DEFAULT_TWI_CLK_HZ;
785 at91_calc_twi_clock(dev, bus_clk_rate);
786 at91_init_twi_bus(dev);
788 snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
789 i2c_set_adapdata(&dev->adapter, dev);
790 dev->adapter.owner = THIS_MODULE;
791 dev->adapter.class = I2C_CLASS_DEPRECATED;
792 dev->adapter.algo = &at91_twi_algorithm;
793 dev->adapter.dev.parent = dev->dev;
794 dev->adapter.nr = pdev->id;
795 dev->adapter.timeout = AT91_I2C_TIMEOUT;
796 dev->adapter.dev.of_node = pdev->dev.of_node;
798 rc = i2c_add_numbered_adapter(&dev->adapter);
800 dev_err(dev->dev, "Adapter %s registration failed\n",
802 clk_disable_unprepare(dev->clk);
806 dev_info(dev->dev, "AT91 i2c bus driver.\n");
810 static int at91_twi_remove(struct platform_device *pdev)
812 struct at91_twi_dev *dev = platform_get_drvdata(pdev);
814 i2c_del_adapter(&dev->adapter);
815 clk_disable_unprepare(dev->clk);
822 static int at91_twi_runtime_suspend(struct device *dev)
824 struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
826 clk_disable(twi_dev->clk);
831 static int at91_twi_runtime_resume(struct device *dev)
833 struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
835 return clk_enable(twi_dev->clk);
838 static const struct dev_pm_ops at91_twi_pm = {
839 .runtime_suspend = at91_twi_runtime_suspend,
840 .runtime_resume = at91_twi_runtime_resume,
843 #define at91_twi_pm_ops (&at91_twi_pm)
845 #define at91_twi_pm_ops NULL
848 static struct platform_driver at91_twi_driver = {
849 .probe = at91_twi_probe,
850 .remove = at91_twi_remove,
851 .id_table = at91_twi_devtypes,
854 .owner = THIS_MODULE,
855 .of_match_table = of_match_ptr(atmel_twi_dt_ids),
856 .pm = at91_twi_pm_ops,
860 static int __init at91_twi_init(void)
862 return platform_driver_register(&at91_twi_driver);
865 static void __exit at91_twi_exit(void)
867 platform_driver_unregister(&at91_twi_driver);
870 subsys_initcall(at91_twi_init);
871 module_exit(at91_twi_exit);
873 MODULE_AUTHOR("Nikolaus Voss <n.voss@weinmann.de>");
874 MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
875 MODULE_LICENSE("GPL");
876 MODULE_ALIAS("platform:at91_i2c");