2 * Synopsys DesignWare I2C adapter driver (master only).
4 * Based on the TI DAVINCI I2C adapter driver.
6 * Copyright (C) 2006 Texas Instruments.
7 * Copyright (C) 2007 MontaVista Software Inc.
8 * Copyright (C) 2009 Provigent Ltd.
10 * ----------------------------------------------------------------------------
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
21 * ----------------------------------------------------------------------------
24 #include <linux/delay.h>
25 #include <linux/err.h>
26 #include <linux/errno.h>
27 #include <linux/export.h>
28 #include <linux/i2c.h>
29 #include <linux/interrupt.h>
31 #include <linux/module.h>
32 #include <linux/pm_runtime.h>
34 #include "i2c-designware-core.h"
36 static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev)
38 /* Configure Tx/Rx FIFO threshold levels */
39 dw_writel(dev, dev->tx_fifo_depth / 2, DW_IC_TX_TL);
40 dw_writel(dev, 0, DW_IC_RX_TL);
42 /* Configure the I2C master */
43 dw_writel(dev, dev->master_cfg, DW_IC_CON);
47 * i2c_dw_init() - Initialize the designware I2C master hardware
48 * @dev: device private data
50 * This functions configures and enables the I2C master.
51 * This function is called during I2C init function, and in case of timeout at
54 static int i2c_dw_init_master(struct dw_i2c_dev *dev)
58 u32 sda_falling_time, scl_falling_time;
61 ret = i2c_dw_acquire_lock(dev);
65 reg = dw_readl(dev, DW_IC_COMP_TYPE);
66 if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) {
67 /* Configure register endianess access */
68 dev->flags |= ACCESS_SWAP;
69 } else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) {
70 /* Configure register access mode 16bit */
71 dev->flags |= ACCESS_16BIT;
72 } else if (reg != DW_IC_COMP_TYPE_VALUE) {
74 "Unknown Synopsys component type: 0x%08x\n", reg);
75 i2c_dw_release_lock(dev);
79 comp_param1 = dw_readl(dev, DW_IC_COMP_PARAM_1);
81 /* Disable the adapter */
82 __i2c_dw_enable_and_wait(dev, false);
84 /* Set standard and fast speed deviders for high/low periods */
86 sda_falling_time = dev->sda_falling_time ?: 300; /* ns */
87 scl_falling_time = dev->scl_falling_time ?: 300; /* ns */
89 /* Set SCL timing parameters for standard-mode */
90 if (dev->ss_hcnt && dev->ss_lcnt) {
94 hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
95 4000, /* tHD;STA = tHIGH = 4.0 us */
97 0, /* 0: DW default, 1: Ideal */
99 lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev),
100 4700, /* tLOW = 4.7 us */
104 dw_writel(dev, hcnt, DW_IC_SS_SCL_HCNT);
105 dw_writel(dev, lcnt, DW_IC_SS_SCL_LCNT);
106 dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
108 /* Set SCL timing parameters for fast-mode or fast-mode plus */
109 if ((dev->clk_freq == 1000000) && dev->fp_hcnt && dev->fp_lcnt) {
112 } else if (dev->fs_hcnt && dev->fs_lcnt) {
116 hcnt = i2c_dw_scl_hcnt(i2c_dw_clk_rate(dev),
117 600, /* tHD;STA = tHIGH = 0.6 us */
119 0, /* 0: DW default, 1: Ideal */
121 lcnt = i2c_dw_scl_lcnt(i2c_dw_clk_rate(dev),
122 1300, /* tLOW = 1.3 us */
126 dw_writel(dev, hcnt, DW_IC_FS_SCL_HCNT);
127 dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);
128 dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
130 if ((dev->master_cfg & DW_IC_CON_SPEED_MASK) ==
131 DW_IC_CON_SPEED_HIGH) {
132 if ((comp_param1 & DW_IC_COMP_PARAM_1_SPEED_MODE_MASK)
133 != DW_IC_COMP_PARAM_1_SPEED_MODE_HIGH) {
134 dev_err(dev->dev, "High Speed not supported!\n");
135 dev->master_cfg &= ~DW_IC_CON_SPEED_MASK;
136 dev->master_cfg |= DW_IC_CON_SPEED_FAST;
137 } else if (dev->hs_hcnt && dev->hs_lcnt) {
140 dw_writel(dev, hcnt, DW_IC_HS_SCL_HCNT);
141 dw_writel(dev, lcnt, DW_IC_HS_SCL_LCNT);
142 dev_dbg(dev->dev, "HighSpeed-mode HCNT:LCNT = %d:%d\n",
147 /* Configure SDA Hold Time if required */
148 reg = dw_readl(dev, DW_IC_COMP_VERSION);
149 if (reg >= DW_IC_SDA_HOLD_MIN_VERS) {
150 if (!dev->sda_hold_time) {
151 /* Keep previous hold time setting if no one set it */
152 dev->sda_hold_time = dw_readl(dev, DW_IC_SDA_HOLD);
155 * Workaround for avoiding TX arbitration lost in case I2C
156 * slave pulls SDA down "too quickly" after falling egde of
157 * SCL by enabling non-zero SDA RX hold. Specification says it
158 * extends incoming SDA low to high transition while SCL is
159 * high but it apprears to help also above issue.
161 if (!(dev->sda_hold_time & DW_IC_SDA_HOLD_RX_MASK))
162 dev->sda_hold_time |= 1 << DW_IC_SDA_HOLD_RX_SHIFT;
163 dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD);
166 "Hardware too old to adjust SDA hold time.\n");
169 i2c_dw_configure_fifo_master(dev);
170 i2c_dw_release_lock(dev);
175 static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
177 struct i2c_msg *msgs = dev->msgs;
178 u32 ic_con, ic_tar = 0;
180 /* Disable the adapter */
181 __i2c_dw_enable_and_wait(dev, false);
183 /* If the slave address is ten bit address, enable 10BITADDR */
184 ic_con = dw_readl(dev, DW_IC_CON);
185 if (msgs[dev->msg_write_idx].flags & I2C_M_TEN) {
186 ic_con |= DW_IC_CON_10BITADDR_MASTER;
188 * If I2C_DYNAMIC_TAR_UPDATE is set, the 10-bit addressing
189 * mode has to be enabled via bit 12 of IC_TAR register.
190 * We set it always as I2C_DYNAMIC_TAR_UPDATE can't be
191 * detected from registers.
193 ic_tar = DW_IC_TAR_10BITADDR_MASTER;
195 ic_con &= ~DW_IC_CON_10BITADDR_MASTER;
198 dw_writel(dev, ic_con, DW_IC_CON);
201 * Set the slave (target) address and enable 10-bit addressing mode
204 dw_writel(dev, msgs[dev->msg_write_idx].addr | ic_tar, DW_IC_TAR);
206 /* Enforce disabled interrupts (due to HW issues) */
207 i2c_dw_disable_int(dev);
209 /* Enable the adapter */
210 __i2c_dw_enable(dev, true);
212 /* Dummy read to avoid the register getting stuck on Bay Trail */
213 dw_readl(dev, DW_IC_ENABLE_STATUS);
215 /* Clear and enable interrupts */
216 dw_readl(dev, DW_IC_CLR_INTR);
217 dw_writel(dev, DW_IC_INTR_MASTER_MASK, DW_IC_INTR_MASK);
221 * Initiate (and continue) low level master read/write transaction.
222 * This function is only called from i2c_dw_isr, and pumping i2c_msg
223 * messages into the tx buffer. Even if the size of i2c_msg data is
224 * longer than the size of the tx buffer, it handles everything.
227 i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
229 struct i2c_msg *msgs = dev->msgs;
231 int tx_limit, rx_limit;
232 u32 addr = msgs[dev->msg_write_idx].addr;
233 u32 buf_len = dev->tx_buf_len;
234 u8 *buf = dev->tx_buf;
235 bool need_restart = false;
237 intr_mask = DW_IC_INTR_MASTER_MASK;
239 for (; dev->msg_write_idx < dev->msgs_num; dev->msg_write_idx++) {
240 u32 flags = msgs[dev->msg_write_idx].flags;
243 * If target address has changed, we need to
244 * reprogram the target address in the I2C
245 * adapter when we are done with this transfer.
247 if (msgs[dev->msg_write_idx].addr != addr) {
249 "%s: invalid target address\n", __func__);
250 dev->msg_err = -EINVAL;
254 if (msgs[dev->msg_write_idx].len == 0) {
256 "%s: invalid message length\n", __func__);
257 dev->msg_err = -EINVAL;
261 if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) {
263 buf = msgs[dev->msg_write_idx].buf;
264 buf_len = msgs[dev->msg_write_idx].len;
266 /* If both IC_EMPTYFIFO_HOLD_MASTER_EN and
267 * IC_RESTART_EN are set, we must manually
268 * set restart bit between messages.
270 if ((dev->master_cfg & DW_IC_CON_RESTART_EN) &&
271 (dev->msg_write_idx > 0))
275 tx_limit = dev->tx_fifo_depth - dw_readl(dev, DW_IC_TXFLR);
276 rx_limit = dev->rx_fifo_depth - dw_readl(dev, DW_IC_RXFLR);
278 while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) {
282 * If IC_EMPTYFIFO_HOLD_MASTER_EN is set we must
283 * manually set the stop bit. However, it cannot be
284 * detected from the registers so we set it always
285 * when writing/reading the last byte.
289 * i2c-core always sets the buffer length of
290 * I2C_FUNC_SMBUS_BLOCK_DATA to 1. The length will
291 * be adjusted when receiving the first byte.
292 * Thus we can't stop the transaction here.
294 if (dev->msg_write_idx == dev->msgs_num - 1 &&
295 buf_len == 1 && !(flags & I2C_M_RECV_LEN))
300 need_restart = false;
303 if (msgs[dev->msg_write_idx].flags & I2C_M_RD) {
305 /* Avoid rx buffer overrun */
306 if (dev->rx_outstanding >= dev->rx_fifo_depth)
309 dw_writel(dev, cmd | 0x100, DW_IC_DATA_CMD);
311 dev->rx_outstanding++;
313 dw_writel(dev, cmd | *buf++, DW_IC_DATA_CMD);
314 tx_limit--; buf_len--;
318 dev->tx_buf_len = buf_len;
321 * Because we don't know the buffer length in the
322 * I2C_FUNC_SMBUS_BLOCK_DATA case, we can't stop
323 * the transaction here.
325 if (buf_len > 0 || flags & I2C_M_RECV_LEN) {
326 /* more bytes to be written */
327 dev->status |= STATUS_WRITE_IN_PROGRESS;
330 dev->status &= ~STATUS_WRITE_IN_PROGRESS;
334 * If i2c_msg index search is completed, we don't need TX_EMPTY
335 * interrupt any more.
337 if (dev->msg_write_idx == dev->msgs_num)
338 intr_mask &= ~DW_IC_INTR_TX_EMPTY;
343 dw_writel(dev, intr_mask, DW_IC_INTR_MASK);
347 i2c_dw_recv_len(struct dw_i2c_dev *dev, u8 len)
349 struct i2c_msg *msgs = dev->msgs;
350 u32 flags = msgs[dev->msg_read_idx].flags;
353 * Adjust the buffer length and mask the flag
354 * after receiving the first byte.
356 len += (flags & I2C_CLIENT_PEC) ? 2 : 1;
357 dev->tx_buf_len = len - min_t(u8, len, dev->rx_outstanding);
358 msgs[dev->msg_read_idx].len = len;
359 msgs[dev->msg_read_idx].flags &= ~I2C_M_RECV_LEN;
365 i2c_dw_read(struct dw_i2c_dev *dev)
367 struct i2c_msg *msgs = dev->msgs;
370 for (; dev->msg_read_idx < dev->msgs_num; dev->msg_read_idx++) {
374 if (!(msgs[dev->msg_read_idx].flags & I2C_M_RD))
377 if (!(dev->status & STATUS_READ_IN_PROGRESS)) {
378 len = msgs[dev->msg_read_idx].len;
379 buf = msgs[dev->msg_read_idx].buf;
381 len = dev->rx_buf_len;
385 rx_valid = dw_readl(dev, DW_IC_RXFLR);
387 for (; len > 0 && rx_valid > 0; len--, rx_valid--) {
388 u32 flags = msgs[dev->msg_read_idx].flags;
390 *buf = dw_readl(dev, DW_IC_DATA_CMD);
391 /* Ensure length byte is a valid value */
392 if (flags & I2C_M_RECV_LEN &&
393 *buf <= I2C_SMBUS_BLOCK_MAX && *buf > 0) {
394 len = i2c_dw_recv_len(dev, *buf);
397 dev->rx_outstanding--;
401 dev->status |= STATUS_READ_IN_PROGRESS;
402 dev->rx_buf_len = len;
406 dev->status &= ~STATUS_READ_IN_PROGRESS;
411 * Prepare controller for a transaction and call i2c_dw_xfer_msg.
414 i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
416 struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
419 dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
421 pm_runtime_get_sync(dev->dev);
423 reinit_completion(&dev->cmd_complete);
427 dev->msg_write_idx = 0;
428 dev->msg_read_idx = 0;
430 dev->status = STATUS_IDLE;
431 dev->abort_source = 0;
432 dev->rx_outstanding = 0;
434 ret = i2c_dw_acquire_lock(dev);
438 ret = i2c_dw_wait_bus_not_busy(dev);
442 /* Start the transfers */
443 i2c_dw_xfer_init(dev);
445 /* Wait for tx to complete */
446 if (!wait_for_completion_timeout(&dev->cmd_complete, adap->timeout)) {
447 dev_err(dev->dev, "controller timed out\n");
448 /* i2c_dw_init implicitly disables the adapter */
449 i2c_dw_init_master(dev);
455 * We must disable the adapter before returning and signaling the end
456 * of the current transfer. Otherwise the hardware might continue
457 * generating interrupts which in turn causes a race condition with
458 * the following transfer. Needs some more investigation if the
459 * additional interrupts are a hardware bug or this driver doesn't
460 * handle them correctly yet.
462 __i2c_dw_enable(dev, false);
470 if (likely(!dev->cmd_err && !dev->status)) {
475 /* We have an error */
476 if (dev->cmd_err == DW_IC_ERR_TX_ABRT) {
477 ret = i2c_dw_handle_tx_abort(dev);
483 "transfer terminated early - interrupt latency too high?\n");
488 i2c_dw_release_lock(dev);
491 pm_runtime_mark_last_busy(dev->dev);
492 pm_runtime_put_autosuspend(dev->dev);
497 static const struct i2c_algorithm i2c_dw_algo = {
498 .master_xfer = i2c_dw_xfer,
499 .functionality = i2c_dw_func,
502 static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
507 * The IC_INTR_STAT register just indicates "enabled" interrupts.
508 * Ths unmasked raw version of interrupt status bits are available
509 * in the IC_RAW_INTR_STAT register.
512 * stat = dw_readl(IC_INTR_STAT);
514 * stat = dw_readl(IC_RAW_INTR_STAT) & dw_readl(IC_INTR_MASK);
516 * The raw version might be useful for debugging purposes.
518 stat = dw_readl(dev, DW_IC_INTR_STAT);
521 * Do not use the IC_CLR_INTR register to clear interrupts, or
522 * you'll miss some interrupts, triggered during the period from
523 * dw_readl(IC_INTR_STAT) to dw_readl(IC_CLR_INTR).
525 * Instead, use the separately-prepared IC_CLR_* registers.
527 if (stat & DW_IC_INTR_RX_UNDER)
528 dw_readl(dev, DW_IC_CLR_RX_UNDER);
529 if (stat & DW_IC_INTR_RX_OVER)
530 dw_readl(dev, DW_IC_CLR_RX_OVER);
531 if (stat & DW_IC_INTR_TX_OVER)
532 dw_readl(dev, DW_IC_CLR_TX_OVER);
533 if (stat & DW_IC_INTR_RD_REQ)
534 dw_readl(dev, DW_IC_CLR_RD_REQ);
535 if (stat & DW_IC_INTR_TX_ABRT) {
537 * The IC_TX_ABRT_SOURCE register is cleared whenever
538 * the IC_CLR_TX_ABRT is read. Preserve it beforehand.
540 dev->abort_source = dw_readl(dev, DW_IC_TX_ABRT_SOURCE);
541 dw_readl(dev, DW_IC_CLR_TX_ABRT);
543 if (stat & DW_IC_INTR_RX_DONE)
544 dw_readl(dev, DW_IC_CLR_RX_DONE);
545 if (stat & DW_IC_INTR_ACTIVITY)
546 dw_readl(dev, DW_IC_CLR_ACTIVITY);
547 if (stat & DW_IC_INTR_STOP_DET)
548 dw_readl(dev, DW_IC_CLR_STOP_DET);
549 if (stat & DW_IC_INTR_START_DET)
550 dw_readl(dev, DW_IC_CLR_START_DET);
551 if (stat & DW_IC_INTR_GEN_CALL)
552 dw_readl(dev, DW_IC_CLR_GEN_CALL);
558 * Interrupt service routine. This gets called whenever an I2C master interrupt
561 static int i2c_dw_irq_handler_master(struct dw_i2c_dev *dev)
565 stat = i2c_dw_read_clear_intrbits(dev);
566 if (stat & DW_IC_INTR_TX_ABRT) {
567 dev->cmd_err |= DW_IC_ERR_TX_ABRT;
568 dev->status = STATUS_IDLE;
571 * Anytime TX_ABRT is set, the contents of the tx/rx
572 * buffers are flushed. Make sure to skip them.
574 dw_writel(dev, 0, DW_IC_INTR_MASK);
578 if (stat & DW_IC_INTR_RX_FULL)
581 if (stat & DW_IC_INTR_TX_EMPTY)
582 i2c_dw_xfer_msg(dev);
585 * No need to modify or disable the interrupt mask here.
586 * i2c_dw_xfer_msg() will take care of it according to
587 * the current transmit status.
591 if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
592 complete(&dev->cmd_complete);
593 else if (unlikely(dev->flags & ACCESS_INTR_MASK)) {
594 /* Workaround to trigger pending interrupt */
595 stat = dw_readl(dev, DW_IC_INTR_MASK);
596 i2c_dw_disable_int(dev);
597 dw_writel(dev, stat, DW_IC_INTR_MASK);
603 static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
605 struct dw_i2c_dev *dev = dev_id;
608 enabled = dw_readl(dev, DW_IC_ENABLE);
609 stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
610 dev_dbg(dev->dev, "enabled=%#x stat=%#x\n", enabled, stat);
611 if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY))
614 i2c_dw_irq_handler_master(dev);
619 int i2c_dw_probe(struct dw_i2c_dev *dev)
621 struct i2c_adapter *adap = &dev->adapter;
622 unsigned long irq_flags;
625 init_completion(&dev->cmd_complete);
627 dev->init = i2c_dw_init_master;
628 dev->disable = i2c_dw_disable;
629 dev->disable_int = i2c_dw_disable_int;
631 ret = dev->init(dev);
635 snprintf(adap->name, sizeof(adap->name),
636 "Synopsys DesignWare I2C adapter");
638 adap->algo = &i2c_dw_algo;
639 adap->dev.parent = dev->dev;
640 i2c_set_adapdata(adap, dev);
642 if (dev->pm_disabled) {
643 dev_pm_syscore_device(dev->dev, true);
644 irq_flags = IRQF_NO_SUSPEND;
646 irq_flags = IRQF_SHARED | IRQF_COND_SUSPEND;
649 i2c_dw_disable_int(dev);
650 ret = devm_request_irq(dev->dev, dev->irq, i2c_dw_isr, irq_flags,
651 dev_name(dev->dev), dev);
653 dev_err(dev->dev, "failure requesting irq %i: %d\n",
659 * Increment PM usage count during adapter registration in order to
660 * avoid possible spurious runtime suspend when adapter device is
661 * registered to the device core and immediate resume in case bus has
662 * registered I2C slaves that do I2C transfers in their probe.
664 pm_runtime_get_noresume(dev->dev);
665 ret = i2c_add_numbered_adapter(adap);
667 dev_err(dev->dev, "failure adding adapter: %d\n", ret);
668 pm_runtime_put_noidle(dev->dev);
672 EXPORT_SYMBOL_GPL(i2c_dw_probe);
674 MODULE_DESCRIPTION("Synopsys DesignWare I2C bus master adapter");
675 MODULE_LICENSE("GPL");