Lines Matching refs:dev
127 struct device *dev; member
146 static unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg) in at91_twi_read() argument
148 return readl_relaxed(dev->base + reg); in at91_twi_read()
151 static void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val) in at91_twi_write() argument
153 writel_relaxed(val, dev->base + reg); in at91_twi_write()
156 static void at91_disable_twi_interrupts(struct at91_twi_dev *dev) in at91_disable_twi_interrupts() argument
158 at91_twi_write(dev, AT91_TWI_IDR, AT91_TWI_INT_MASK); in at91_disable_twi_interrupts()
161 static void at91_twi_irq_save(struct at91_twi_dev *dev) in at91_twi_irq_save() argument
163 dev->imr = at91_twi_read(dev, AT91_TWI_IMR) & AT91_TWI_INT_MASK; in at91_twi_irq_save()
164 at91_disable_twi_interrupts(dev); in at91_twi_irq_save()
167 static void at91_twi_irq_restore(struct at91_twi_dev *dev) in at91_twi_irq_restore() argument
169 at91_twi_write(dev, AT91_TWI_IER, dev->imr); in at91_twi_irq_restore()
172 static void at91_init_twi_bus(struct at91_twi_dev *dev) in at91_init_twi_bus() argument
174 at91_disable_twi_interrupts(dev); in at91_init_twi_bus()
175 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST); in at91_init_twi_bus()
177 if (dev->fifo_size) in at91_init_twi_bus()
178 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_FIFOEN); in at91_init_twi_bus()
179 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_MSEN); in at91_init_twi_bus()
180 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SVDIS); in at91_init_twi_bus()
181 at91_twi_write(dev, AT91_TWI_CWGR, dev->twi_cwgr_reg); in at91_init_twi_bus()
188 static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk) in at91_calc_twi_clock() argument
191 struct at91_twi_pdata *pdata = dev->pdata; in at91_calc_twi_clock()
195 div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk), in at91_calc_twi_clock()
201 dev_warn(dev->dev, "%d exceeds ckdiv max value which is %d.\n", in at91_calc_twi_clock()
207 dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv; in at91_calc_twi_clock()
208 dev_dbg(dev->dev, "cdiv %d ckdiv %d\n", cdiv, ckdiv); in at91_calc_twi_clock()
211 static void at91_twi_dma_cleanup(struct at91_twi_dev *dev) in at91_twi_dma_cleanup() argument
213 struct at91_twi_dma *dma = &dev->dma; in at91_twi_dma_cleanup()
215 at91_twi_irq_save(dev); in at91_twi_dma_cleanup()
225 dma_unmap_single(dev->dev, sg_dma_address(&dma->sg[0]), in at91_twi_dma_cleanup()
226 dev->buf_len, dma->direction); in at91_twi_dma_cleanup()
230 at91_twi_irq_restore(dev); in at91_twi_dma_cleanup()
233 static void at91_twi_write_next_byte(struct at91_twi_dev *dev) in at91_twi_write_next_byte() argument
235 if (!dev->buf_len) in at91_twi_write_next_byte()
239 writeb_relaxed(*dev->buf, dev->base + AT91_TWI_THR); in at91_twi_write_next_byte()
242 if (--dev->buf_len == 0) in at91_twi_write_next_byte()
243 if (!dev->pdata->has_alt_cmd) in at91_twi_write_next_byte()
244 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP); in at91_twi_write_next_byte()
246 dev_dbg(dev->dev, "wrote 0x%x, to go %d\n", *dev->buf, dev->buf_len); in at91_twi_write_next_byte()
248 ++dev->buf; in at91_twi_write_next_byte()
253 struct at91_twi_dev *dev = (struct at91_twi_dev *)data; in at91_twi_write_data_dma_callback() local
255 dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg[0]), in at91_twi_write_data_dma_callback()
256 dev->buf_len, DMA_TO_DEVICE); in at91_twi_write_data_dma_callback()
265 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP); in at91_twi_write_data_dma_callback()
266 if (!dev->pdata->has_alt_cmd) in at91_twi_write_data_dma_callback()
267 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP); in at91_twi_write_data_dma_callback()
270 static void at91_twi_write_data_dma(struct at91_twi_dev *dev) in at91_twi_write_data_dma() argument
274 struct at91_twi_dma *dma = &dev->dma; in at91_twi_write_data_dma()
278 if (!dev->buf_len) in at91_twi_write_data_dma()
283 at91_twi_irq_save(dev); in at91_twi_write_data_dma()
284 dma_addr = dma_map_single(dev->dev, dev->buf, dev->buf_len, in at91_twi_write_data_dma()
286 if (dma_mapping_error(dev->dev, dma_addr)) { in at91_twi_write_data_dma()
287 dev_err(dev->dev, "dma map failed\n"); in at91_twi_write_data_dma()
291 at91_twi_irq_restore(dev); in at91_twi_write_data_dma()
293 if (dev->fifo_size) { in at91_twi_write_data_dma()
300 part1_len = dev->buf_len & ~0x3; in at91_twi_write_data_dma()
307 part2_len = dev->buf_len & 0x3; in at91_twi_write_data_dma()
318 fifo_mr = at91_twi_read(dev, AT91_TWI_FMR); in at91_twi_write_data_dma()
321 at91_twi_write(dev, AT91_TWI_FMR, fifo_mr); in at91_twi_write_data_dma()
323 sg_dma_len(&dma->sg[0]) = dev->buf_len; in at91_twi_write_data_dma()
331 dev_err(dev->dev, "dma prep slave sg failed\n"); in at91_twi_write_data_dma()
336 txdesc->callback_param = dev; in at91_twi_write_data_dma()
345 at91_twi_dma_cleanup(dev); in at91_twi_write_data_dma()
348 static void at91_twi_read_next_byte(struct at91_twi_dev *dev) in at91_twi_read_next_byte() argument
354 if (!dev->buf_len) { in at91_twi_read_next_byte()
355 at91_twi_read(dev, AT91_TWI_RHR); in at91_twi_read_next_byte()
360 *dev->buf = readb_relaxed(dev->base + AT91_TWI_RHR); in at91_twi_read_next_byte()
361 --dev->buf_len; in at91_twi_read_next_byte()
364 if (dev->recv_len_abort) in at91_twi_read_next_byte()
368 if (unlikely(dev->msg->flags & I2C_M_RECV_LEN)) { in at91_twi_read_next_byte()
370 if (*dev->buf <= I2C_SMBUS_BLOCK_MAX && *dev->buf > 0) { in at91_twi_read_next_byte()
371 dev->msg->flags &= ~I2C_M_RECV_LEN; in at91_twi_read_next_byte()
372 dev->buf_len += *dev->buf; in at91_twi_read_next_byte()
373 dev->msg->len = dev->buf_len + 1; in at91_twi_read_next_byte()
374 dev_dbg(dev->dev, "received block length %d\n", in at91_twi_read_next_byte()
375 dev->buf_len); in at91_twi_read_next_byte()
378 dev->recv_len_abort = true; in at91_twi_read_next_byte()
379 dev->buf_len = 1; in at91_twi_read_next_byte()
384 if (!dev->pdata->has_alt_cmd && dev->buf_len == 1) in at91_twi_read_next_byte()
385 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP); in at91_twi_read_next_byte()
387 dev_dbg(dev->dev, "read 0x%x, to go %d\n", *dev->buf, dev->buf_len); in at91_twi_read_next_byte()
389 ++dev->buf; in at91_twi_read_next_byte()
394 struct at91_twi_dev *dev = (struct at91_twi_dev *)data; in at91_twi_read_data_dma_callback() local
397 dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg[0]), in at91_twi_read_data_dma_callback()
398 dev->buf_len, DMA_FROM_DEVICE); in at91_twi_read_data_dma_callback()
400 if (!dev->pdata->has_alt_cmd) { in at91_twi_read_data_dma_callback()
402 dev->buf += dev->buf_len - 2; in at91_twi_read_data_dma_callback()
403 dev->buf_len = 2; in at91_twi_read_data_dma_callback()
406 at91_twi_write(dev, AT91_TWI_IER, ier); in at91_twi_read_data_dma_callback()
409 static void at91_twi_read_data_dma(struct at91_twi_dev *dev) in at91_twi_read_data_dma() argument
413 struct at91_twi_dma *dma = &dev->dma; in at91_twi_read_data_dma()
417 buf_len = (dev->pdata->has_alt_cmd) ? dev->buf_len : dev->buf_len - 2; in at91_twi_read_data_dma()
421 at91_twi_irq_save(dev); in at91_twi_read_data_dma()
422 dma_addr = dma_map_single(dev->dev, dev->buf, buf_len, DMA_FROM_DEVICE); in at91_twi_read_data_dma()
423 if (dma_mapping_error(dev->dev, dma_addr)) { in at91_twi_read_data_dma()
424 dev_err(dev->dev, "dma map failed\n"); in at91_twi_read_data_dma()
428 at91_twi_irq_restore(dev); in at91_twi_read_data_dma()
430 if (dev->fifo_size && IS_ALIGNED(buf_len, 4)) { in at91_twi_read_data_dma()
437 fifo_mr = at91_twi_read(dev, AT91_TWI_FMR); in at91_twi_read_data_dma()
440 at91_twi_write(dev, AT91_TWI_FMR, fifo_mr); in at91_twi_read_data_dma()
449 dev_err(dev->dev, "dma prep slave sg failed\n"); in at91_twi_read_data_dma()
454 rxdesc->callback_param = dev; in at91_twi_read_data_dma()
463 at91_twi_dma_cleanup(dev); in at91_twi_read_data_dma()
468 struct at91_twi_dev *dev = dev_id; in atmel_twi_interrupt() local
469 const unsigned status = at91_twi_read(dev, AT91_TWI_SR); in atmel_twi_interrupt()
470 const unsigned irqstatus = status & at91_twi_read(dev, AT91_TWI_IMR); in atmel_twi_interrupt()
491 at91_twi_read_next_byte(dev); in atmel_twi_interrupt()
532 at91_disable_twi_interrupts(dev); in atmel_twi_interrupt()
533 complete(&dev->cmd_complete); in atmel_twi_interrupt()
535 at91_twi_write_next_byte(dev); in atmel_twi_interrupt()
539 dev->transfer_status |= status; in atmel_twi_interrupt()
544 static int at91_do_twi_transfer(struct at91_twi_dev *dev) in at91_do_twi_transfer() argument
548 bool has_unre_flag = dev->pdata->has_unre_flag; in at91_do_twi_transfer()
549 bool has_alt_cmd = dev->pdata->has_alt_cmd; in at91_do_twi_transfer()
594 dev_dbg(dev->dev, "transfer: %s %d bytes.\n", in at91_do_twi_transfer()
595 (dev->msg->flags & I2C_M_RD) ? "read" : "write", dev->buf_len); in at91_do_twi_transfer()
597 reinit_completion(&dev->cmd_complete); in at91_do_twi_transfer()
598 dev->transfer_status = 0; in at91_do_twi_transfer()
601 at91_twi_read(dev, AT91_TWI_SR); in at91_do_twi_transfer()
603 if (dev->fifo_size) { in at91_do_twi_transfer()
604 unsigned fifo_mr = at91_twi_read(dev, AT91_TWI_FMR); in at91_do_twi_transfer()
611 at91_twi_write(dev, AT91_TWI_FMR, fifo_mr); in at91_do_twi_transfer()
614 at91_twi_write(dev, AT91_TWI_CR, in at91_do_twi_transfer()
618 if (!dev->buf_len) { in at91_do_twi_transfer()
619 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_QUICK); in at91_do_twi_transfer()
620 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP); in at91_do_twi_transfer()
621 } else if (dev->msg->flags & I2C_M_RD) { in at91_do_twi_transfer()
625 if (!has_alt_cmd && dev->buf_len <= 1 && in at91_do_twi_transfer()
626 !(dev->msg->flags & I2C_M_RECV_LEN)) in at91_do_twi_transfer()
628 at91_twi_write(dev, AT91_TWI_CR, start_flags); in at91_do_twi_transfer()
638 if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) { in at91_do_twi_transfer()
639 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_NACK); in at91_do_twi_transfer()
640 at91_twi_read_data_dma(dev); in at91_do_twi_transfer()
642 at91_twi_write(dev, AT91_TWI_IER, in at91_do_twi_transfer()
648 if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) { in at91_do_twi_transfer()
649 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_NACK); in at91_do_twi_transfer()
650 at91_twi_write_data_dma(dev); in at91_do_twi_transfer()
652 at91_twi_write_next_byte(dev); in at91_do_twi_transfer()
653 at91_twi_write(dev, AT91_TWI_IER, in at91_do_twi_transfer()
660 time_left = wait_for_completion_timeout(&dev->cmd_complete, in at91_do_twi_transfer()
661 dev->adapter.timeout); in at91_do_twi_transfer()
663 dev->transfer_status |= at91_twi_read(dev, AT91_TWI_SR); in at91_do_twi_transfer()
664 dev_err(dev->dev, "controller timed out\n"); in at91_do_twi_transfer()
665 at91_init_twi_bus(dev); in at91_do_twi_transfer()
669 if (dev->transfer_status & AT91_TWI_NACK) { in at91_do_twi_transfer()
670 dev_dbg(dev->dev, "received nack\n"); in at91_do_twi_transfer()
674 if (dev->transfer_status & AT91_TWI_OVRE) { in at91_do_twi_transfer()
675 dev_err(dev->dev, "overrun while reading\n"); in at91_do_twi_transfer()
679 if (has_unre_flag && dev->transfer_status & AT91_TWI_UNRE) { in at91_do_twi_transfer()
680 dev_err(dev->dev, "underrun while writing\n"); in at91_do_twi_transfer()
684 if ((has_alt_cmd || dev->fifo_size) && in at91_do_twi_transfer()
685 (dev->transfer_status & AT91_TWI_LOCK)) { in at91_do_twi_transfer()
686 dev_err(dev->dev, "tx locked\n"); in at91_do_twi_transfer()
690 if (dev->recv_len_abort) { in at91_do_twi_transfer()
691 dev_err(dev->dev, "invalid smbus block length recvd\n"); in at91_do_twi_transfer()
696 dev_dbg(dev->dev, "transfer complete\n"); in at91_do_twi_transfer()
702 at91_twi_dma_cleanup(dev); in at91_do_twi_transfer()
704 if ((has_alt_cmd || dev->fifo_size) && in at91_do_twi_transfer()
705 (dev->transfer_status & AT91_TWI_LOCK)) { in at91_do_twi_transfer()
706 dev_dbg(dev->dev, "unlock tx\n"); in at91_do_twi_transfer()
707 at91_twi_write(dev, AT91_TWI_CR, in at91_do_twi_transfer()
715 struct at91_twi_dev *dev = i2c_get_adapdata(adap); in at91_twi_xfer() local
721 dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num); in at91_twi_xfer()
723 ret = pm_runtime_get_sync(dev->dev); in at91_twi_xfer()
739 at91_twi_write(dev, AT91_TWI_IADR, internal_address); in at91_twi_xfer()
743 if (dev->pdata->has_alt_cmd) { in at91_twi_xfer()
745 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_ACMEN); in at91_twi_xfer()
746 at91_twi_write(dev, AT91_TWI_ACR, in at91_twi_xfer()
751 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_ACMDIS); in at91_twi_xfer()
755 at91_twi_write(dev, AT91_TWI_MMR, in at91_twi_xfer()
760 dev->buf_len = m_start->len; in at91_twi_xfer()
761 dev->buf = m_start->buf; in at91_twi_xfer()
762 dev->msg = m_start; in at91_twi_xfer()
763 dev->recv_len_abort = false; in at91_twi_xfer()
765 ret = at91_do_twi_transfer(dev); in at91_twi_xfer()
769 pm_runtime_mark_last_busy(dev->dev); in at91_twi_xfer()
770 pm_runtime_put_autosuspend(dev->dev); in at91_twi_xfer()
895 static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr) in at91_twi_configure_dma() argument
899 struct at91_twi_dma *dma = &dev->dma; in at91_twi_configure_dma()
917 if (dev->fifo_size) in at91_twi_configure_dma()
929 dma->chan_tx = dma_request_slave_channel_reason(dev->dev, "tx"); in at91_twi_configure_dma()
936 dma->chan_rx = dma_request_slave_channel_reason(dev->dev, "rx"); in at91_twi_configure_dma()
945 dev_err(dev->dev, "failed to configure tx channel\n"); in at91_twi_configure_dma()
952 dev_err(dev->dev, "failed to configure rx channel\n"); in at91_twi_configure_dma()
960 dev->use_dma = true; in at91_twi_configure_dma()
962 dev_info(dev->dev, "using %s (tx) and %s (rx) for DMA transfers\n", in at91_twi_configure_dma()
969 dev_info(dev->dev, "can't use DMA, error %d\n", ret); in at91_twi_configure_dma()
980 if (pdev->dev.of_node) { in at91_twi_get_driver_data()
982 match = of_match_node(atmel_twi_dt_ids, pdev->dev.of_node); in at91_twi_get_driver_data()
992 struct at91_twi_dev *dev; in at91_twi_probe() local
998 dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL); in at91_twi_probe()
999 if (!dev) in at91_twi_probe()
1001 init_completion(&dev->cmd_complete); in at91_twi_probe()
1002 dev->dev = &pdev->dev; in at91_twi_probe()
1009 dev->pdata = at91_twi_get_driver_data(pdev); in at91_twi_probe()
1010 if (!dev->pdata) in at91_twi_probe()
1013 dev->base = devm_ioremap_resource(&pdev->dev, mem); in at91_twi_probe()
1014 if (IS_ERR(dev->base)) in at91_twi_probe()
1015 return PTR_ERR(dev->base); in at91_twi_probe()
1017 dev->irq = platform_get_irq(pdev, 0); in at91_twi_probe()
1018 if (dev->irq < 0) in at91_twi_probe()
1019 return dev->irq; in at91_twi_probe()
1021 rc = devm_request_irq(&pdev->dev, dev->irq, atmel_twi_interrupt, 0, in at91_twi_probe()
1022 dev_name(dev->dev), dev); in at91_twi_probe()
1024 dev_err(dev->dev, "Cannot get irq %d: %d\n", dev->irq, rc); in at91_twi_probe()
1028 platform_set_drvdata(pdev, dev); in at91_twi_probe()
1030 dev->clk = devm_clk_get(dev->dev, NULL); in at91_twi_probe()
1031 if (IS_ERR(dev->clk)) { in at91_twi_probe()
1032 dev_err(dev->dev, "no clock defined\n"); in at91_twi_probe()
1035 clk_prepare_enable(dev->clk); in at91_twi_probe()
1037 if (dev->dev->of_node) { in at91_twi_probe()
1038 rc = at91_twi_configure_dma(dev, phy_addr); in at91_twi_probe()
1043 if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size", in at91_twi_probe()
1044 &dev->fifo_size)) { in at91_twi_probe()
1045 dev_info(dev->dev, "Using FIFO (%u data)\n", dev->fifo_size); in at91_twi_probe()
1048 rc = of_property_read_u32(dev->dev->of_node, "clock-frequency", in at91_twi_probe()
1053 at91_calc_twi_clock(dev, bus_clk_rate); in at91_twi_probe()
1054 at91_init_twi_bus(dev); in at91_twi_probe()
1056 snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91"); in at91_twi_probe()
1057 i2c_set_adapdata(&dev->adapter, dev); in at91_twi_probe()
1058 dev->adapter.owner = THIS_MODULE; in at91_twi_probe()
1059 dev->adapter.class = I2C_CLASS_DEPRECATED; in at91_twi_probe()
1060 dev->adapter.algo = &at91_twi_algorithm; in at91_twi_probe()
1061 dev->adapter.quirks = &at91_twi_quirks; in at91_twi_probe()
1062 dev->adapter.dev.parent = dev->dev; in at91_twi_probe()
1063 dev->adapter.nr = pdev->id; in at91_twi_probe()
1064 dev->adapter.timeout = AT91_I2C_TIMEOUT; in at91_twi_probe()
1065 dev->adapter.dev.of_node = pdev->dev.of_node; in at91_twi_probe()
1067 pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT); in at91_twi_probe()
1068 pm_runtime_use_autosuspend(dev->dev); in at91_twi_probe()
1069 pm_runtime_set_active(dev->dev); in at91_twi_probe()
1070 pm_runtime_enable(dev->dev); in at91_twi_probe()
1072 rc = i2c_add_numbered_adapter(&dev->adapter); in at91_twi_probe()
1074 dev_err(dev->dev, "Adapter %s registration failed\n", in at91_twi_probe()
1075 dev->adapter.name); in at91_twi_probe()
1076 clk_disable_unprepare(dev->clk); in at91_twi_probe()
1078 pm_runtime_disable(dev->dev); in at91_twi_probe()
1079 pm_runtime_set_suspended(dev->dev); in at91_twi_probe()
1084 dev_info(dev->dev, "AT91 i2c bus driver (hw version: %#x).\n", in at91_twi_probe()
1085 at91_twi_read(dev, AT91_TWI_VER)); in at91_twi_probe()
1091 struct at91_twi_dev *dev = platform_get_drvdata(pdev); in at91_twi_remove() local
1093 i2c_del_adapter(&dev->adapter); in at91_twi_remove()
1094 clk_disable_unprepare(dev->clk); in at91_twi_remove()
1096 pm_runtime_disable(dev->dev); in at91_twi_remove()
1097 pm_runtime_set_suspended(dev->dev); in at91_twi_remove()
1104 static int at91_twi_runtime_suspend(struct device *dev) in at91_twi_runtime_suspend() argument
1106 struct at91_twi_dev *twi_dev = dev_get_drvdata(dev); in at91_twi_runtime_suspend()
1110 pinctrl_pm_select_sleep_state(dev); in at91_twi_runtime_suspend()
1115 static int at91_twi_runtime_resume(struct device *dev) in at91_twi_runtime_resume() argument
1117 struct at91_twi_dev *twi_dev = dev_get_drvdata(dev); in at91_twi_runtime_resume()
1119 pinctrl_pm_select_default_state(dev); in at91_twi_runtime_resume()
1124 static int at91_twi_suspend_noirq(struct device *dev) in at91_twi_suspend_noirq() argument
1126 if (!pm_runtime_status_suspended(dev)) in at91_twi_suspend_noirq()
1127 at91_twi_runtime_suspend(dev); in at91_twi_suspend_noirq()
1132 static int at91_twi_resume_noirq(struct device *dev) in at91_twi_resume_noirq() argument
1136 if (!pm_runtime_status_suspended(dev)) { in at91_twi_resume_noirq()
1137 ret = at91_twi_runtime_resume(dev); in at91_twi_resume_noirq()
1142 pm_runtime_mark_last_busy(dev); in at91_twi_resume_noirq()
1143 pm_request_autosuspend(dev); in at91_twi_resume_noirq()