1 /*
2 * Synopsys DesignWare I2C adapter driver (master only).
3 *
4 * Based on the TI DAVINCI I2C adapter driver.
5 *
6 * Copyright (C) 2006 Texas Instruments.
7 * Copyright (C) 2007 MontaVista Software Inc.
8 * Copyright (C) 2009 Provigent Ltd.
9 *
10 * ----------------------------------------------------------------------------
11 *
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.
16 *
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 * ----------------------------------------------------------------------------
22 *
23 */
24 #include <linux/export.h>
25 #include <linux/errno.h>
26 #include <linux/err.h>
27 #include <linux/i2c.h>
28 #include <linux/interrupt.h>
29 #include <linux/io.h>
30 #include <linux/pm_runtime.h>
31 #include <linux/delay.h>
32 #include <linux/module.h>
33 #include "i2c-designware-core.h"
34
35 /*
36 * Registers offset
37 */
38 #define DW_IC_CON 0x0
39 #define DW_IC_TAR 0x4
40 #define DW_IC_DATA_CMD 0x10
41 #define DW_IC_SS_SCL_HCNT 0x14
42 #define DW_IC_SS_SCL_LCNT 0x18
43 #define DW_IC_FS_SCL_HCNT 0x1c
44 #define DW_IC_FS_SCL_LCNT 0x20
45 #define DW_IC_INTR_STAT 0x2c
46 #define DW_IC_INTR_MASK 0x30
47 #define DW_IC_RAW_INTR_STAT 0x34
48 #define DW_IC_RX_TL 0x38
49 #define DW_IC_TX_TL 0x3c
50 #define DW_IC_CLR_INTR 0x40
51 #define DW_IC_CLR_RX_UNDER 0x44
52 #define DW_IC_CLR_RX_OVER 0x48
53 #define DW_IC_CLR_TX_OVER 0x4c
54 #define DW_IC_CLR_RD_REQ 0x50
55 #define DW_IC_CLR_TX_ABRT 0x54
56 #define DW_IC_CLR_RX_DONE 0x58
57 #define DW_IC_CLR_ACTIVITY 0x5c
58 #define DW_IC_CLR_STOP_DET 0x60
59 #define DW_IC_CLR_START_DET 0x64
60 #define DW_IC_CLR_GEN_CALL 0x68
61 #define DW_IC_ENABLE 0x6c
62 #define DW_IC_STATUS 0x70
63 #define DW_IC_TXFLR 0x74
64 #define DW_IC_RXFLR 0x78
65 #define DW_IC_SDA_HOLD 0x7c
66 #define DW_IC_TX_ABRT_SOURCE 0x80
67 #define DW_IC_ENABLE_STATUS 0x9c
68 #define DW_IC_COMP_PARAM_1 0xf4
69 #define DW_IC_COMP_VERSION 0xf8
70 #define DW_IC_SDA_HOLD_MIN_VERS 0x3131312A
71 #define DW_IC_COMP_TYPE 0xfc
72 #define DW_IC_COMP_TYPE_VALUE 0x44570140
73
74 #define DW_IC_INTR_RX_UNDER 0x001
75 #define DW_IC_INTR_RX_OVER 0x002
76 #define DW_IC_INTR_RX_FULL 0x004
77 #define DW_IC_INTR_TX_OVER 0x008
78 #define DW_IC_INTR_TX_EMPTY 0x010
79 #define DW_IC_INTR_RD_REQ 0x020
80 #define DW_IC_INTR_TX_ABRT 0x040
81 #define DW_IC_INTR_RX_DONE 0x080
82 #define DW_IC_INTR_ACTIVITY 0x100
83 #define DW_IC_INTR_STOP_DET 0x200
84 #define DW_IC_INTR_START_DET 0x400
85 #define DW_IC_INTR_GEN_CALL 0x800
86
87 #define DW_IC_INTR_DEFAULT_MASK (DW_IC_INTR_RX_FULL | \
88 DW_IC_INTR_TX_EMPTY | \
89 DW_IC_INTR_TX_ABRT | \
90 DW_IC_INTR_STOP_DET)
91
92 #define DW_IC_STATUS_ACTIVITY 0x1
93
94 #define DW_IC_ERR_TX_ABRT 0x1
95
96 #define DW_IC_TAR_10BITADDR_MASTER BIT(12)
97
98 /*
99 * status codes
100 */
101 #define STATUS_IDLE 0x0
102 #define STATUS_WRITE_IN_PROGRESS 0x1
103 #define STATUS_READ_IN_PROGRESS 0x2
104
105 #define TIMEOUT 20 /* ms */
106
107 /*
108 * hardware abort codes from the DW_IC_TX_ABRT_SOURCE register
109 *
110 * only expected abort codes are listed here
111 * refer to the datasheet for the full list
112 */
113 #define ABRT_7B_ADDR_NOACK 0
114 #define ABRT_10ADDR1_NOACK 1
115 #define ABRT_10ADDR2_NOACK 2
116 #define ABRT_TXDATA_NOACK 3
117 #define ABRT_GCALL_NOACK 4
118 #define ABRT_GCALL_READ 5
119 #define ABRT_SBYTE_ACKDET 7
120 #define ABRT_SBYTE_NORSTRT 9
121 #define ABRT_10B_RD_NORSTRT 10
122 #define ABRT_MASTER_DIS 11
123 #define ARB_LOST 12
124
125 #define DW_IC_TX_ABRT_7B_ADDR_NOACK (1UL << ABRT_7B_ADDR_NOACK)
126 #define DW_IC_TX_ABRT_10ADDR1_NOACK (1UL << ABRT_10ADDR1_NOACK)
127 #define DW_IC_TX_ABRT_10ADDR2_NOACK (1UL << ABRT_10ADDR2_NOACK)
128 #define DW_IC_TX_ABRT_TXDATA_NOACK (1UL << ABRT_TXDATA_NOACK)
129 #define DW_IC_TX_ABRT_GCALL_NOACK (1UL << ABRT_GCALL_NOACK)
130 #define DW_IC_TX_ABRT_GCALL_READ (1UL << ABRT_GCALL_READ)
131 #define DW_IC_TX_ABRT_SBYTE_ACKDET (1UL << ABRT_SBYTE_ACKDET)
132 #define DW_IC_TX_ABRT_SBYTE_NORSTRT (1UL << ABRT_SBYTE_NORSTRT)
133 #define DW_IC_TX_ABRT_10B_RD_NORSTRT (1UL << ABRT_10B_RD_NORSTRT)
134 #define DW_IC_TX_ABRT_MASTER_DIS (1UL << ABRT_MASTER_DIS)
135 #define DW_IC_TX_ARB_LOST (1UL << ARB_LOST)
136
137 #define DW_IC_TX_ABRT_NOACK (DW_IC_TX_ABRT_7B_ADDR_NOACK | \
138 DW_IC_TX_ABRT_10ADDR1_NOACK | \
139 DW_IC_TX_ABRT_10ADDR2_NOACK | \
140 DW_IC_TX_ABRT_TXDATA_NOACK | \
141 DW_IC_TX_ABRT_GCALL_NOACK)
142
143 static char *abort_sources[] = {
144 [ABRT_7B_ADDR_NOACK] =
145 "slave address not acknowledged (7bit mode)",
146 [ABRT_10ADDR1_NOACK] =
147 "first address byte not acknowledged (10bit mode)",
148 [ABRT_10ADDR2_NOACK] =
149 "second address byte not acknowledged (10bit mode)",
150 [ABRT_TXDATA_NOACK] =
151 "data not acknowledged",
152 [ABRT_GCALL_NOACK] =
153 "no acknowledgement for a general call",
154 [ABRT_GCALL_READ] =
155 "read after general call",
156 [ABRT_SBYTE_ACKDET] =
157 "start byte acknowledged",
158 [ABRT_SBYTE_NORSTRT] =
159 "trying to send start byte when restart is disabled",
160 [ABRT_10B_RD_NORSTRT] =
161 "trying to read when restart is disabled (10bit mode)",
162 [ABRT_MASTER_DIS] =
163 "trying to use disabled adapter",
164 [ARB_LOST] =
165 "lost arbitration",
166 };
167
dw_readl(struct dw_i2c_dev * dev,int offset)168 u32 dw_readl(struct dw_i2c_dev *dev, int offset)
169 {
170 u32 value;
171
172 if (dev->accessor_flags & ACCESS_16BIT)
173 value = readw(dev->base + offset) |
174 (readw(dev->base + offset + 2) << 16);
175 else
176 value = readl(dev->base + offset);
177
178 if (dev->accessor_flags & ACCESS_SWAP)
179 return swab32(value);
180 else
181 return value;
182 }
183
dw_writel(struct dw_i2c_dev * dev,u32 b,int offset)184 void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset)
185 {
186 if (dev->accessor_flags & ACCESS_SWAP)
187 b = swab32(b);
188
189 if (dev->accessor_flags & ACCESS_16BIT) {
190 writew((u16)b, dev->base + offset);
191 writew((u16)(b >> 16), dev->base + offset + 2);
192 } else {
193 writel(b, dev->base + offset);
194 }
195 }
196
197 static u32
i2c_dw_scl_hcnt(u32 ic_clk,u32 tSYMBOL,u32 tf,int cond,int offset)198 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset)
199 {
200 /*
201 * DesignWare I2C core doesn't seem to have solid strategy to meet
202 * the tHD;STA timing spec. Configuring _HCNT based on tHIGH spec
203 * will result in violation of the tHD;STA spec.
204 */
205 if (cond)
206 /*
207 * Conditional expression:
208 *
209 * IC_[FS]S_SCL_HCNT + (1+4+3) >= IC_CLK * tHIGH
210 *
211 * This is based on the DW manuals, and represents an ideal
212 * configuration. The resulting I2C bus speed will be
213 * faster than any of the others.
214 *
215 * If your hardware is free from tHD;STA issue, try this one.
216 */
217 return (ic_clk * tSYMBOL + 500000) / 1000000 - 8 + offset;
218 else
219 /*
220 * Conditional expression:
221 *
222 * IC_[FS]S_SCL_HCNT + 3 >= IC_CLK * (tHD;STA + tf)
223 *
224 * This is just experimental rule; the tHD;STA period turned
225 * out to be proportinal to (_HCNT + 3). With this setting,
226 * we could meet both tHIGH and tHD;STA timing specs.
227 *
228 * If unsure, you'd better to take this alternative.
229 *
230 * The reason why we need to take into account "tf" here,
231 * is the same as described in i2c_dw_scl_lcnt().
232 */
233 return (ic_clk * (tSYMBOL + tf) + 500000) / 1000000
234 - 3 + offset;
235 }
236
i2c_dw_scl_lcnt(u32 ic_clk,u32 tLOW,u32 tf,int offset)237 static u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset)
238 {
239 /*
240 * Conditional expression:
241 *
242 * IC_[FS]S_SCL_LCNT + 1 >= IC_CLK * (tLOW + tf)
243 *
244 * DW I2C core starts counting the SCL CNTs for the LOW period
245 * of the SCL clock (tLOW) as soon as it pulls the SCL line.
246 * In order to meet the tLOW timing spec, we need to take into
247 * account the fall time of SCL signal (tf). Default tf value
248 * should be 0.3 us, for safety.
249 */
250 return ((ic_clk * (tLOW + tf) + 500000) / 1000000) - 1 + offset;
251 }
252
__i2c_dw_enable(struct dw_i2c_dev * dev,bool enable)253 static void __i2c_dw_enable(struct dw_i2c_dev *dev, bool enable)
254 {
255 int timeout = 100;
256
257 do {
258 dw_writel(dev, enable, DW_IC_ENABLE);
259 if ((dw_readl(dev, DW_IC_ENABLE_STATUS) & 1) == enable)
260 return;
261
262 /*
263 * Wait 10 times the signaling period of the highest I2C
264 * transfer supported by the driver (for 400KHz this is
265 * 25us) as described in the DesignWare I2C databook.
266 */
267 usleep_range(25, 250);
268 } while (timeout--);
269
270 dev_warn(dev->dev, "timeout in %sabling adapter\n",
271 enable ? "en" : "dis");
272 }
273
274 /**
275 * i2c_dw_init() - initialize the designware i2c master hardware
276 * @dev: device private data
277 *
278 * This functions configures and enables the I2C master.
279 * This function is called during I2C init function, and in case of timeout at
280 * run time.
281 */
i2c_dw_init(struct dw_i2c_dev * dev)282 int i2c_dw_init(struct dw_i2c_dev *dev)
283 {
284 u32 input_clock_khz;
285 u32 hcnt, lcnt;
286 u32 reg;
287 u32 sda_falling_time, scl_falling_time;
288
289 input_clock_khz = dev->get_clk_rate_khz(dev);
290
291 reg = dw_readl(dev, DW_IC_COMP_TYPE);
292 if (reg == ___constant_swab32(DW_IC_COMP_TYPE_VALUE)) {
293 /* Configure register endianess access */
294 dev->accessor_flags |= ACCESS_SWAP;
295 } else if (reg == (DW_IC_COMP_TYPE_VALUE & 0x0000ffff)) {
296 /* Configure register access mode 16bit */
297 dev->accessor_flags |= ACCESS_16BIT;
298 } else if (reg != DW_IC_COMP_TYPE_VALUE) {
299 dev_err(dev->dev, "Unknown Synopsys component type: "
300 "0x%08x\n", reg);
301 return -ENODEV;
302 }
303
304 /* Disable the adapter */
305 __i2c_dw_enable(dev, false);
306
307 /* set standard and fast speed deviders for high/low periods */
308
309 sda_falling_time = dev->sda_falling_time ?: 300; /* ns */
310 scl_falling_time = dev->scl_falling_time ?: 300; /* ns */
311
312 /* Standard-mode */
313 hcnt = i2c_dw_scl_hcnt(input_clock_khz,
314 4000, /* tHD;STA = tHIGH = 4.0 us */
315 sda_falling_time,
316 0, /* 0: DW default, 1: Ideal */
317 0); /* No offset */
318 lcnt = i2c_dw_scl_lcnt(input_clock_khz,
319 4700, /* tLOW = 4.7 us */
320 scl_falling_time,
321 0); /* No offset */
322
323 /* Allow platforms to specify the ideal HCNT and LCNT values */
324 if (dev->ss_hcnt && dev->ss_lcnt) {
325 hcnt = dev->ss_hcnt;
326 lcnt = dev->ss_lcnt;
327 }
328 dw_writel(dev, hcnt, DW_IC_SS_SCL_HCNT);
329 dw_writel(dev, lcnt, DW_IC_SS_SCL_LCNT);
330 dev_dbg(dev->dev, "Standard-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
331
332 /* Fast-mode */
333 hcnt = i2c_dw_scl_hcnt(input_clock_khz,
334 600, /* tHD;STA = tHIGH = 0.6 us */
335 sda_falling_time,
336 0, /* 0: DW default, 1: Ideal */
337 0); /* No offset */
338 lcnt = i2c_dw_scl_lcnt(input_clock_khz,
339 1300, /* tLOW = 1.3 us */
340 scl_falling_time,
341 0); /* No offset */
342
343 if (dev->fs_hcnt && dev->fs_lcnt) {
344 hcnt = dev->fs_hcnt;
345 lcnt = dev->fs_lcnt;
346 }
347 dw_writel(dev, hcnt, DW_IC_FS_SCL_HCNT);
348 dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT);
349 dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt);
350
351 /* Configure SDA Hold Time if required */
352 if (dev->sda_hold_time) {
353 reg = dw_readl(dev, DW_IC_COMP_VERSION);
354 if (reg >= DW_IC_SDA_HOLD_MIN_VERS)
355 dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD);
356 else
357 dev_warn(dev->dev,
358 "Hardware too old to adjust SDA hold time.");
359 }
360
361 /* Configure Tx/Rx FIFO threshold levels */
362 dw_writel(dev, dev->tx_fifo_depth / 2, DW_IC_TX_TL);
363 dw_writel(dev, 0, DW_IC_RX_TL);
364
365 /* configure the i2c master */
366 dw_writel(dev, dev->master_cfg , DW_IC_CON);
367 return 0;
368 }
369 EXPORT_SYMBOL_GPL(i2c_dw_init);
370
371 /*
372 * Waiting for bus not busy
373 */
i2c_dw_wait_bus_not_busy(struct dw_i2c_dev * dev)374 static int i2c_dw_wait_bus_not_busy(struct dw_i2c_dev *dev)
375 {
376 int timeout = TIMEOUT;
377
378 while (dw_readl(dev, DW_IC_STATUS) & DW_IC_STATUS_ACTIVITY) {
379 if (timeout <= 0) {
380 dev_warn(dev->dev, "timeout waiting for bus ready\n");
381 return -ETIMEDOUT;
382 }
383 timeout--;
384 usleep_range(1000, 1100);
385 }
386
387 return 0;
388 }
389
i2c_dw_xfer_init(struct dw_i2c_dev * dev)390 static void i2c_dw_xfer_init(struct dw_i2c_dev *dev)
391 {
392 struct i2c_msg *msgs = dev->msgs;
393 u32 ic_con, ic_tar = 0;
394
395 /* Disable the adapter */
396 __i2c_dw_enable(dev, false);
397
398 /* if the slave address is ten bit address, enable 10BITADDR */
399 ic_con = dw_readl(dev, DW_IC_CON);
400 if (msgs[dev->msg_write_idx].flags & I2C_M_TEN) {
401 ic_con |= DW_IC_CON_10BITADDR_MASTER;
402 /*
403 * If I2C_DYNAMIC_TAR_UPDATE is set, the 10-bit addressing
404 * mode has to be enabled via bit 12 of IC_TAR register.
405 * We set it always as I2C_DYNAMIC_TAR_UPDATE can't be
406 * detected from registers.
407 */
408 ic_tar = DW_IC_TAR_10BITADDR_MASTER;
409 } else {
410 ic_con &= ~DW_IC_CON_10BITADDR_MASTER;
411 }
412
413 dw_writel(dev, ic_con, DW_IC_CON);
414
415 /*
416 * Set the slave (target) address and enable 10-bit addressing mode
417 * if applicable.
418 */
419 dw_writel(dev, msgs[dev->msg_write_idx].addr | ic_tar, DW_IC_TAR);
420
421 /* enforce disabled interrupts (due to HW issues) */
422 i2c_dw_disable_int(dev);
423
424 /* Enable the adapter */
425 __i2c_dw_enable(dev, true);
426
427 /* Clear and enable interrupts */
428 i2c_dw_clear_int(dev);
429 dw_writel(dev, DW_IC_INTR_DEFAULT_MASK, DW_IC_INTR_MASK);
430 }
431
432 /*
433 * Initiate (and continue) low level master read/write transaction.
434 * This function is only called from i2c_dw_isr, and pumping i2c_msg
435 * messages into the tx buffer. Even if the size of i2c_msg data is
436 * longer than the size of the tx buffer, it handles everything.
437 */
438 static void
i2c_dw_xfer_msg(struct dw_i2c_dev * dev)439 i2c_dw_xfer_msg(struct dw_i2c_dev *dev)
440 {
441 struct i2c_msg *msgs = dev->msgs;
442 u32 intr_mask;
443 int tx_limit, rx_limit;
444 u32 addr = msgs[dev->msg_write_idx].addr;
445 u32 buf_len = dev->tx_buf_len;
446 u8 *buf = dev->tx_buf;
447 bool need_restart = false;
448
449 intr_mask = DW_IC_INTR_DEFAULT_MASK;
450
451 for (; dev->msg_write_idx < dev->msgs_num; dev->msg_write_idx++) {
452 /*
453 * if target address has changed, we need to
454 * reprogram the target address in the i2c
455 * adapter when we are done with this transfer
456 */
457 if (msgs[dev->msg_write_idx].addr != addr) {
458 dev_err(dev->dev,
459 "%s: invalid target address\n", __func__);
460 dev->msg_err = -EINVAL;
461 break;
462 }
463
464 if (msgs[dev->msg_write_idx].len == 0) {
465 dev_err(dev->dev,
466 "%s: invalid message length\n", __func__);
467 dev->msg_err = -EINVAL;
468 break;
469 }
470
471 if (!(dev->status & STATUS_WRITE_IN_PROGRESS)) {
472 /* new i2c_msg */
473 buf = msgs[dev->msg_write_idx].buf;
474 buf_len = msgs[dev->msg_write_idx].len;
475
476 /* If both IC_EMPTYFIFO_HOLD_MASTER_EN and
477 * IC_RESTART_EN are set, we must manually
478 * set restart bit between messages.
479 */
480 if ((dev->master_cfg & DW_IC_CON_RESTART_EN) &&
481 (dev->msg_write_idx > 0))
482 need_restart = true;
483 }
484
485 tx_limit = dev->tx_fifo_depth - dw_readl(dev, DW_IC_TXFLR);
486 rx_limit = dev->rx_fifo_depth - dw_readl(dev, DW_IC_RXFLR);
487
488 while (buf_len > 0 && tx_limit > 0 && rx_limit > 0) {
489 u32 cmd = 0;
490
491 /*
492 * If IC_EMPTYFIFO_HOLD_MASTER_EN is set we must
493 * manually set the stop bit. However, it cannot be
494 * detected from the registers so we set it always
495 * when writing/reading the last byte.
496 */
497 if (dev->msg_write_idx == dev->msgs_num - 1 &&
498 buf_len == 1)
499 cmd |= BIT(9);
500
501 if (need_restart) {
502 cmd |= BIT(10);
503 need_restart = false;
504 }
505
506 if (msgs[dev->msg_write_idx].flags & I2C_M_RD) {
507
508 /* avoid rx buffer overrun */
509 if (rx_limit - dev->rx_outstanding <= 0)
510 break;
511
512 dw_writel(dev, cmd | 0x100, DW_IC_DATA_CMD);
513 rx_limit--;
514 dev->rx_outstanding++;
515 } else
516 dw_writel(dev, cmd | *buf++, DW_IC_DATA_CMD);
517 tx_limit--; buf_len--;
518 }
519
520 dev->tx_buf = buf;
521 dev->tx_buf_len = buf_len;
522
523 if (buf_len > 0) {
524 /* more bytes to be written */
525 dev->status |= STATUS_WRITE_IN_PROGRESS;
526 break;
527 } else
528 dev->status &= ~STATUS_WRITE_IN_PROGRESS;
529 }
530
531 /*
532 * If i2c_msg index search is completed, we don't need TX_EMPTY
533 * interrupt any more.
534 */
535 if (dev->msg_write_idx == dev->msgs_num)
536 intr_mask &= ~DW_IC_INTR_TX_EMPTY;
537
538 if (dev->msg_err)
539 intr_mask = 0;
540
541 dw_writel(dev, intr_mask, DW_IC_INTR_MASK);
542 }
543
544 static void
i2c_dw_read(struct dw_i2c_dev * dev)545 i2c_dw_read(struct dw_i2c_dev *dev)
546 {
547 struct i2c_msg *msgs = dev->msgs;
548 int rx_valid;
549
550 for (; dev->msg_read_idx < dev->msgs_num; dev->msg_read_idx++) {
551 u32 len;
552 u8 *buf;
553
554 if (!(msgs[dev->msg_read_idx].flags & I2C_M_RD))
555 continue;
556
557 if (!(dev->status & STATUS_READ_IN_PROGRESS)) {
558 len = msgs[dev->msg_read_idx].len;
559 buf = msgs[dev->msg_read_idx].buf;
560 } else {
561 len = dev->rx_buf_len;
562 buf = dev->rx_buf;
563 }
564
565 rx_valid = dw_readl(dev, DW_IC_RXFLR);
566
567 for (; len > 0 && rx_valid > 0; len--, rx_valid--) {
568 *buf++ = dw_readl(dev, DW_IC_DATA_CMD);
569 dev->rx_outstanding--;
570 }
571
572 if (len > 0) {
573 dev->status |= STATUS_READ_IN_PROGRESS;
574 dev->rx_buf_len = len;
575 dev->rx_buf = buf;
576 return;
577 } else
578 dev->status &= ~STATUS_READ_IN_PROGRESS;
579 }
580 }
581
i2c_dw_handle_tx_abort(struct dw_i2c_dev * dev)582 static int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev)
583 {
584 unsigned long abort_source = dev->abort_source;
585 int i;
586
587 if (abort_source & DW_IC_TX_ABRT_NOACK) {
588 for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
589 dev_dbg(dev->dev,
590 "%s: %s\n", __func__, abort_sources[i]);
591 return -EREMOTEIO;
592 }
593
594 for_each_set_bit(i, &abort_source, ARRAY_SIZE(abort_sources))
595 dev_err(dev->dev, "%s: %s\n", __func__, abort_sources[i]);
596
597 if (abort_source & DW_IC_TX_ARB_LOST)
598 return -EAGAIN;
599 else if (abort_source & DW_IC_TX_ABRT_GCALL_READ)
600 return -EINVAL; /* wrong msgs[] data */
601 else
602 return -EIO;
603 }
604
605 /*
606 * Prepare controller for a transaction and call i2c_dw_xfer_msg
607 */
608 int
i2c_dw_xfer(struct i2c_adapter * adap,struct i2c_msg msgs[],int num)609 i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
610 {
611 struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
612 int ret;
613
614 dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
615
616 mutex_lock(&dev->lock);
617 pm_runtime_get_sync(dev->dev);
618
619 reinit_completion(&dev->cmd_complete);
620 dev->msgs = msgs;
621 dev->msgs_num = num;
622 dev->cmd_err = 0;
623 dev->msg_write_idx = 0;
624 dev->msg_read_idx = 0;
625 dev->msg_err = 0;
626 dev->status = STATUS_IDLE;
627 dev->abort_source = 0;
628 dev->rx_outstanding = 0;
629
630 ret = i2c_dw_wait_bus_not_busy(dev);
631 if (ret < 0)
632 goto done;
633
634 /* start the transfers */
635 i2c_dw_xfer_init(dev);
636
637 /* wait for tx to complete */
638 ret = wait_for_completion_timeout(&dev->cmd_complete, HZ);
639 if (ret == 0) {
640 dev_err(dev->dev, "controller timed out\n");
641 /* i2c_dw_init implicitly disables the adapter */
642 i2c_dw_init(dev);
643 ret = -ETIMEDOUT;
644 goto done;
645 }
646
647 /*
648 * We must disable the adapter before unlocking the &dev->lock mutex
649 * below. Otherwise the hardware might continue generating interrupts
650 * which in turn causes a race condition with the following transfer.
651 * Needs some more investigation if the additional interrupts are
652 * a hardware bug or this driver doesn't handle them correctly yet.
653 */
654 __i2c_dw_enable(dev, false);
655
656 if (dev->msg_err) {
657 ret = dev->msg_err;
658 goto done;
659 }
660
661 /* no error */
662 if (likely(!dev->cmd_err)) {
663 ret = num;
664 goto done;
665 }
666
667 /* We have an error */
668 if (dev->cmd_err == DW_IC_ERR_TX_ABRT) {
669 ret = i2c_dw_handle_tx_abort(dev);
670 goto done;
671 }
672 ret = -EIO;
673
674 done:
675 pm_runtime_mark_last_busy(dev->dev);
676 pm_runtime_put_autosuspend(dev->dev);
677 mutex_unlock(&dev->lock);
678
679 return ret;
680 }
681 EXPORT_SYMBOL_GPL(i2c_dw_xfer);
682
i2c_dw_func(struct i2c_adapter * adap)683 u32 i2c_dw_func(struct i2c_adapter *adap)
684 {
685 struct dw_i2c_dev *dev = i2c_get_adapdata(adap);
686 return dev->functionality;
687 }
688 EXPORT_SYMBOL_GPL(i2c_dw_func);
689
i2c_dw_read_clear_intrbits(struct dw_i2c_dev * dev)690 static u32 i2c_dw_read_clear_intrbits(struct dw_i2c_dev *dev)
691 {
692 u32 stat;
693
694 /*
695 * The IC_INTR_STAT register just indicates "enabled" interrupts.
696 * Ths unmasked raw version of interrupt status bits are available
697 * in the IC_RAW_INTR_STAT register.
698 *
699 * That is,
700 * stat = dw_readl(IC_INTR_STAT);
701 * equals to,
702 * stat = dw_readl(IC_RAW_INTR_STAT) & dw_readl(IC_INTR_MASK);
703 *
704 * The raw version might be useful for debugging purposes.
705 */
706 stat = dw_readl(dev, DW_IC_INTR_STAT);
707
708 /*
709 * Do not use the IC_CLR_INTR register to clear interrupts, or
710 * you'll miss some interrupts, triggered during the period from
711 * dw_readl(IC_INTR_STAT) to dw_readl(IC_CLR_INTR).
712 *
713 * Instead, use the separately-prepared IC_CLR_* registers.
714 */
715 if (stat & DW_IC_INTR_RX_UNDER)
716 dw_readl(dev, DW_IC_CLR_RX_UNDER);
717 if (stat & DW_IC_INTR_RX_OVER)
718 dw_readl(dev, DW_IC_CLR_RX_OVER);
719 if (stat & DW_IC_INTR_TX_OVER)
720 dw_readl(dev, DW_IC_CLR_TX_OVER);
721 if (stat & DW_IC_INTR_RD_REQ)
722 dw_readl(dev, DW_IC_CLR_RD_REQ);
723 if (stat & DW_IC_INTR_TX_ABRT) {
724 /*
725 * The IC_TX_ABRT_SOURCE register is cleared whenever
726 * the IC_CLR_TX_ABRT is read. Preserve it beforehand.
727 */
728 dev->abort_source = dw_readl(dev, DW_IC_TX_ABRT_SOURCE);
729 dw_readl(dev, DW_IC_CLR_TX_ABRT);
730 }
731 if (stat & DW_IC_INTR_RX_DONE)
732 dw_readl(dev, DW_IC_CLR_RX_DONE);
733 if (stat & DW_IC_INTR_ACTIVITY)
734 dw_readl(dev, DW_IC_CLR_ACTIVITY);
735 if (stat & DW_IC_INTR_STOP_DET)
736 dw_readl(dev, DW_IC_CLR_STOP_DET);
737 if (stat & DW_IC_INTR_START_DET)
738 dw_readl(dev, DW_IC_CLR_START_DET);
739 if (stat & DW_IC_INTR_GEN_CALL)
740 dw_readl(dev, DW_IC_CLR_GEN_CALL);
741
742 return stat;
743 }
744
745 /*
746 * Interrupt service routine. This gets called whenever an I2C interrupt
747 * occurs.
748 */
i2c_dw_isr(int this_irq,void * dev_id)749 irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
750 {
751 struct dw_i2c_dev *dev = dev_id;
752 u32 stat, enabled;
753
754 enabled = dw_readl(dev, DW_IC_ENABLE);
755 stat = dw_readl(dev, DW_IC_RAW_INTR_STAT);
756 dev_dbg(dev->dev, "%s: %s enabled= 0x%x stat=0x%x\n", __func__,
757 dev->adapter.name, enabled, stat);
758 if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY))
759 return IRQ_NONE;
760
761 stat = i2c_dw_read_clear_intrbits(dev);
762
763 if (stat & DW_IC_INTR_TX_ABRT) {
764 dev->cmd_err |= DW_IC_ERR_TX_ABRT;
765 dev->status = STATUS_IDLE;
766
767 /*
768 * Anytime TX_ABRT is set, the contents of the tx/rx
769 * buffers are flushed. Make sure to skip them.
770 */
771 dw_writel(dev, 0, DW_IC_INTR_MASK);
772 goto tx_aborted;
773 }
774
775 if (stat & DW_IC_INTR_RX_FULL)
776 i2c_dw_read(dev);
777
778 if (stat & DW_IC_INTR_TX_EMPTY)
779 i2c_dw_xfer_msg(dev);
780
781 /*
782 * No need to modify or disable the interrupt mask here.
783 * i2c_dw_xfer_msg() will take care of it according to
784 * the current transmit status.
785 */
786
787 tx_aborted:
788 if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
789 complete(&dev->cmd_complete);
790
791 return IRQ_HANDLED;
792 }
793 EXPORT_SYMBOL_GPL(i2c_dw_isr);
794
i2c_dw_enable(struct dw_i2c_dev * dev)795 void i2c_dw_enable(struct dw_i2c_dev *dev)
796 {
797 /* Enable the adapter */
798 __i2c_dw_enable(dev, true);
799 }
800 EXPORT_SYMBOL_GPL(i2c_dw_enable);
801
i2c_dw_is_enabled(struct dw_i2c_dev * dev)802 u32 i2c_dw_is_enabled(struct dw_i2c_dev *dev)
803 {
804 return dw_readl(dev, DW_IC_ENABLE);
805 }
806 EXPORT_SYMBOL_GPL(i2c_dw_is_enabled);
807
i2c_dw_disable(struct dw_i2c_dev * dev)808 void i2c_dw_disable(struct dw_i2c_dev *dev)
809 {
810 /* Disable controller */
811 __i2c_dw_enable(dev, false);
812
813 /* Disable all interupts */
814 dw_writel(dev, 0, DW_IC_INTR_MASK);
815 dw_readl(dev, DW_IC_CLR_INTR);
816 }
817 EXPORT_SYMBOL_GPL(i2c_dw_disable);
818
i2c_dw_clear_int(struct dw_i2c_dev * dev)819 void i2c_dw_clear_int(struct dw_i2c_dev *dev)
820 {
821 dw_readl(dev, DW_IC_CLR_INTR);
822 }
823 EXPORT_SYMBOL_GPL(i2c_dw_clear_int);
824
i2c_dw_disable_int(struct dw_i2c_dev * dev)825 void i2c_dw_disable_int(struct dw_i2c_dev *dev)
826 {
827 dw_writel(dev, 0, DW_IC_INTR_MASK);
828 }
829 EXPORT_SYMBOL_GPL(i2c_dw_disable_int);
830
i2c_dw_read_comp_param(struct dw_i2c_dev * dev)831 u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev)
832 {
833 return dw_readl(dev, DW_IC_COMP_PARAM_1);
834 }
835 EXPORT_SYMBOL_GPL(i2c_dw_read_comp_param);
836
837 MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter core");
838 MODULE_LICENSE("GPL");
839