1// SPDX-License-Identifier: GPL-2.0-or-later
2/* linux/drivers/i2c/busses/i2c-s3c2410.c
3 *
4 * Copyright (C) 2004,2005,2009 Simtec Electronics
5 * Ben Dooks <ben@simtec.co.uk>
6 *
7 * S3C2410 I2C Controller
8*/
9
10#include <linux/kernel.h>
11#include <linux/module.h>
12
13#include <linux/i2c.h>
14#include <linux/init.h>
15#include <linux/time.h>
16#include <linux/interrupt.h>
17#include <linux/delay.h>
18#include <linux/errno.h>
19#include <linux/err.h>
20#include <linux/platform_device.h>
21#include <linux/pm_runtime.h>
22#include <linux/clk.h>
23#include <linux/cpufreq.h>
24#include <linux/slab.h>
25#include <linux/io.h>
26#include <linux/of.h>
27#include <linux/gpio/consumer.h>
28#include <linux/pinctrl/consumer.h>
29#include <linux/mfd/syscon.h>
30#include <linux/regmap.h>
31
32#include <asm/irq.h>
33
34#include <linux/platform_data/i2c-s3c2410.h>
35
36/* see s3c2410x user guide, v1.1, section 9 (p447) for more info */
37
38#define S3C2410_IICCON 0x00
39#define S3C2410_IICSTAT 0x04
40#define S3C2410_IICADD 0x08
41#define S3C2410_IICDS 0x0C
42#define S3C2440_IICLC 0x10
43
44#define S3C2410_IICCON_ACKEN (1 << 7)
45#define S3C2410_IICCON_TXDIV_16 (0 << 6)
46#define S3C2410_IICCON_TXDIV_512 (1 << 6)
47#define S3C2410_IICCON_IRQEN (1 << 5)
48#define S3C2410_IICCON_IRQPEND (1 << 4)
49#define S3C2410_IICCON_SCALE(x) ((x) & 0xf)
50#define S3C2410_IICCON_SCALEMASK (0xf)
51
52#define S3C2410_IICSTAT_MASTER_RX (2 << 6)
53#define S3C2410_IICSTAT_MASTER_TX (3 << 6)
54#define S3C2410_IICSTAT_SLAVE_RX (0 << 6)
55#define S3C2410_IICSTAT_SLAVE_TX (1 << 6)
56#define S3C2410_IICSTAT_MODEMASK (3 << 6)
57
58#define S3C2410_IICSTAT_START (1 << 5)
59#define S3C2410_IICSTAT_BUSBUSY (1 << 5)
60#define S3C2410_IICSTAT_TXRXEN (1 << 4)
61#define S3C2410_IICSTAT_ARBITR (1 << 3)
62#define S3C2410_IICSTAT_ASSLAVE (1 << 2)
63#define S3C2410_IICSTAT_ADDR0 (1 << 1)
64#define S3C2410_IICSTAT_LASTBIT (1 << 0)
65
66#define S3C2410_IICLC_SDA_DELAY0 (0 << 0)
67#define S3C2410_IICLC_SDA_DELAY5 (1 << 0)
68#define S3C2410_IICLC_SDA_DELAY10 (2 << 0)
69#define S3C2410_IICLC_SDA_DELAY15 (3 << 0)
70#define S3C2410_IICLC_SDA_DELAY_MASK (3 << 0)
71
72#define S3C2410_IICLC_FILTER_ON (1 << 2)
73
74/* Treat S3C2410 as baseline hardware, anything else is supported via quirks */
75#define QUIRK_S3C2440 (1 << 0)
76#define QUIRK_HDMIPHY (1 << 1)
77#define QUIRK_NO_GPIO (1 << 2)
78#define QUIRK_POLL (1 << 3)
79
80/* Max time to wait for bus to become idle after a xfer (in us) */
81#define S3C2410_IDLE_TIMEOUT 5000
82
83/* Exynos5 Sysreg offset */
84#define EXYNOS5_SYS_I2C_CFG 0x0234
85
86/* i2c controller state */
87enum s3c24xx_i2c_state {
88 STATE_IDLE,
89 STATE_START,
90 STATE_READ,
91 STATE_WRITE,
92 STATE_STOP
93};
94
95struct s3c24xx_i2c {
96 wait_queue_head_t wait;
97 kernel_ulong_t quirks;
98
99 struct i2c_msg *msg;
100 unsigned int msg_num;
101 unsigned int msg_idx;
102 unsigned int msg_ptr;
103
104 unsigned int tx_setup;
105 unsigned int irq;
106
107 enum s3c24xx_i2c_state state;
108 unsigned long clkrate;
109
110 void __iomem *regs;
111 struct clk *clk;
112 struct device *dev;
113 struct i2c_adapter adap;
114
115 struct s3c2410_platform_i2c *pdata;
116 struct gpio_desc *gpios[2];
117 struct pinctrl *pctrl;
118 struct regmap *sysreg;
119 unsigned int sys_i2c_cfg;
120};
121
122static const struct platform_device_id s3c24xx_driver_ids[] = {
123 {
124 .name = "s3c2410-i2c",
125 .driver_data = 0,
126 }, {
127 .name = "s3c2440-i2c",
128 .driver_data = QUIRK_S3C2440,
129 }, {
130 .name = "s3c2440-hdmiphy-i2c",
131 .driver_data = QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO,
132 }, { },
133};
134MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
135
136static void i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat);
137
138#ifdef CONFIG_OF
139static const struct of_device_id s3c24xx_i2c_match[] = {
140 { .compatible = "samsung,s3c2410-i2c", .data = (void *)0 },
141 { .compatible = "samsung,s3c2440-i2c", .data = (void *)QUIRK_S3C2440 },
142 { .compatible = "samsung,s3c2440-hdmiphy-i2c",
143 .data = (void *)(QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO) },
144 { .compatible = "samsung,exynos5-sata-phy-i2c",
145 .data = (void *)(QUIRK_S3C2440 | QUIRK_POLL | QUIRK_NO_GPIO) },
146 {},
147};
148MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
149#endif
150
151/*
152 * Get controller type either from device tree or platform device variant.
153 */
154static inline kernel_ulong_t s3c24xx_get_device_quirks(struct platform_device *pdev)
155{
156 if (pdev->dev.of_node)
157 return (kernel_ulong_t)of_device_get_match_data(dev: &pdev->dev);
158
159 return platform_get_device_id(pdev)->driver_data;
160}
161
162/*
163 * Complete the message and wake up the caller, using the given return code,
164 * or zero to mean ok.
165 */
166static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
167{
168 dev_dbg(i2c->dev, "master_complete %d\n", ret);
169
170 i2c->msg_ptr = 0;
171 i2c->msg = NULL;
172 i2c->msg_idx++;
173 i2c->msg_num = 0;
174 if (ret)
175 i2c->msg_idx = ret;
176
177 if (!(i2c->quirks & QUIRK_POLL))
178 wake_up(&i2c->wait);
179}
180
181static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
182{
183 unsigned long tmp;
184
185 tmp = readl(addr: i2c->regs + S3C2410_IICCON);
186 writel(val: tmp & ~S3C2410_IICCON_ACKEN, addr: i2c->regs + S3C2410_IICCON);
187}
188
189static inline void s3c24xx_i2c_enable_ack(struct s3c24xx_i2c *i2c)
190{
191 unsigned long tmp;
192
193 tmp = readl(addr: i2c->regs + S3C2410_IICCON);
194 writel(val: tmp | S3C2410_IICCON_ACKEN, addr: i2c->regs + S3C2410_IICCON);
195}
196
197/* irq enable/disable functions */
198static inline void s3c24xx_i2c_disable_irq(struct s3c24xx_i2c *i2c)
199{
200 unsigned long tmp;
201
202 tmp = readl(addr: i2c->regs + S3C2410_IICCON);
203 writel(val: tmp & ~S3C2410_IICCON_IRQEN, addr: i2c->regs + S3C2410_IICCON);
204}
205
206static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
207{
208 unsigned long tmp;
209
210 tmp = readl(addr: i2c->regs + S3C2410_IICCON);
211 writel(val: tmp | S3C2410_IICCON_IRQEN, addr: i2c->regs + S3C2410_IICCON);
212}
213
214static bool is_ack(struct s3c24xx_i2c *i2c)
215{
216 int tries;
217
218 for (tries = 50; tries; --tries) {
219 if (readl(addr: i2c->regs + S3C2410_IICCON)
220 & S3C2410_IICCON_IRQPEND) {
221 if (!(readl(addr: i2c->regs + S3C2410_IICSTAT)
222 & S3C2410_IICSTAT_LASTBIT))
223 return true;
224 }
225 usleep_range(min: 1000, max: 2000);
226 }
227 dev_err(i2c->dev, "ack was not received\n");
228 return false;
229}
230
231/*
232 * put the start of a message onto the bus
233 */
234static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
235 struct i2c_msg *msg)
236{
237 unsigned int addr = (msg->addr & 0x7f) << 1;
238 unsigned long stat;
239 unsigned long iiccon;
240
241 stat = 0;
242 stat |= S3C2410_IICSTAT_TXRXEN;
243
244 if (msg->flags & I2C_M_RD) {
245 stat |= S3C2410_IICSTAT_MASTER_RX;
246 addr |= 1;
247 } else
248 stat |= S3C2410_IICSTAT_MASTER_TX;
249
250 if (msg->flags & I2C_M_REV_DIR_ADDR)
251 addr ^= 1;
252
253 /* todo - check for whether ack wanted or not */
254 s3c24xx_i2c_enable_ack(i2c);
255
256 iiccon = readl(addr: i2c->regs + S3C2410_IICCON);
257 writel(val: stat, addr: i2c->regs + S3C2410_IICSTAT);
258
259 dev_dbg(i2c->dev, "START: %08lx to IICSTAT, %02x to DS\n", stat, addr);
260 writeb(val: addr, addr: i2c->regs + S3C2410_IICDS);
261
262 /*
263 * delay here to ensure the data byte has gotten onto the bus
264 * before the transaction is started
265 */
266 ndelay(i2c->tx_setup);
267
268 dev_dbg(i2c->dev, "iiccon, %08lx\n", iiccon);
269 writel(val: iiccon, addr: i2c->regs + S3C2410_IICCON);
270
271 stat |= S3C2410_IICSTAT_START;
272 writel(val: stat, addr: i2c->regs + S3C2410_IICSTAT);
273
274 if (i2c->quirks & QUIRK_POLL) {
275 while ((i2c->msg_num != 0) && is_ack(i2c)) {
276 i2c_s3c_irq_nextbyte(i2c, iicstat: stat);
277 stat = readl(addr: i2c->regs + S3C2410_IICSTAT);
278
279 if (stat & S3C2410_IICSTAT_ARBITR)
280 dev_err(i2c->dev, "deal with arbitration loss\n");
281 }
282 }
283}
284
285static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
286{
287 unsigned long iicstat = readl(addr: i2c->regs + S3C2410_IICSTAT);
288
289 dev_dbg(i2c->dev, "STOP\n");
290
291 /*
292 * The datasheet says that the STOP sequence should be:
293 * 1) I2CSTAT.5 = 0 - Clear BUSY (or 'generate STOP')
294 * 2) I2CCON.4 = 0 - Clear IRQPEND
295 * 3) Wait until the stop condition takes effect.
296 * 4*) I2CSTAT.4 = 0 - Clear TXRXEN
297 *
298 * Where, step "4*" is only for buses with the "HDMIPHY" quirk.
299 *
300 * However, after much experimentation, it appears that:
301 * a) normal buses automatically clear BUSY and transition from
302 * Master->Slave when they complete generating a STOP condition.
303 * Therefore, step (3) can be done in doxfer() by polling I2CCON.4
304 * after starting the STOP generation here.
305 * b) HDMIPHY bus does neither, so there is no way to do step 3.
306 * There is no indication when this bus has finished generating
307 * STOP.
308 *
309 * In fact, we have found that as soon as the IRQPEND bit is cleared in
310 * step 2, the HDMIPHY bus generates the STOP condition, and then
311 * immediately starts transferring another data byte, even though the
312 * bus is supposedly stopped. This is presumably because the bus is
313 * still in "Master" mode, and its BUSY bit is still set.
314 *
315 * To avoid these extra post-STOP transactions on HDMI phy devices, we
316 * just disable Serial Output on the bus (I2CSTAT.4 = 0) directly,
317 * instead of first generating a proper STOP condition. This should
318 * float SDA & SCK terminating the transfer. Subsequent transfers
319 * start with a proper START condition, and proceed normally.
320 *
321 * The HDMIPHY bus is an internal bus that always has exactly two
322 * devices, the host as Master and the HDMIPHY device as the slave.
323 * Skipping the STOP condition has been tested on this bus and works.
324 */
325 if (i2c->quirks & QUIRK_HDMIPHY) {
326 /* Stop driving the I2C pins */
327 iicstat &= ~S3C2410_IICSTAT_TXRXEN;
328 } else {
329 /* stop the transfer */
330 iicstat &= ~S3C2410_IICSTAT_START;
331 }
332 writel(val: iicstat, addr: i2c->regs + S3C2410_IICSTAT);
333
334 i2c->state = STATE_STOP;
335
336 s3c24xx_i2c_master_complete(i2c, ret);
337 s3c24xx_i2c_disable_irq(i2c);
338}
339
340/*
341 * helper functions to determine the current state in the set of
342 * messages we are sending
343 */
344
345/*
346 * returns TRUE if the current message is the last in the set
347 */
348static inline int is_lastmsg(struct s3c24xx_i2c *i2c)
349{
350 return i2c->msg_idx >= (i2c->msg_num - 1);
351}
352
353/*
354 * returns TRUE if we this is the last byte in the current message
355 */
356static inline int is_msglast(struct s3c24xx_i2c *i2c)
357{
358 /*
359 * msg->len is always 1 for the first byte of smbus block read.
360 * Actual length will be read from slave. More bytes will be
361 * read according to the length then.
362 */
363 if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1)
364 return 0;
365
366 return i2c->msg_ptr == i2c->msg->len-1;
367}
368
369/*
370 * returns TRUE if we reached the end of the current message
371 */
372static inline int is_msgend(struct s3c24xx_i2c *i2c)
373{
374 return i2c->msg_ptr >= i2c->msg->len;
375}
376
377/*
378 * process an interrupt and work out what to do
379 */
380static void i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat)
381{
382 unsigned long tmp;
383 unsigned char byte;
384
385 switch (i2c->state) {
386
387 case STATE_IDLE:
388 dev_err(i2c->dev, "%s: called in STATE_IDLE\n", __func__);
389 goto out;
390
391 case STATE_STOP:
392 dev_err(i2c->dev, "%s: called in STATE_STOP\n", __func__);
393 s3c24xx_i2c_disable_irq(i2c);
394 goto out_ack;
395
396 case STATE_START:
397 /*
398 * last thing we did was send a start condition on the
399 * bus, or started a new i2c message
400 */
401 if (iicstat & S3C2410_IICSTAT_LASTBIT &&
402 !(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
403 /* ack was not received... */
404 dev_dbg(i2c->dev, "ack was not received\n");
405 s3c24xx_i2c_stop(i2c, ret: -ENXIO);
406 goto out_ack;
407 }
408
409 if (i2c->msg->flags & I2C_M_RD)
410 i2c->state = STATE_READ;
411 else
412 i2c->state = STATE_WRITE;
413
414 /*
415 * Terminate the transfer if there is nothing to do
416 * as this is used by the i2c probe to find devices.
417 */
418 if (is_lastmsg(i2c) && i2c->msg->len == 0) {
419 s3c24xx_i2c_stop(i2c, ret: 0);
420 goto out_ack;
421 }
422
423 if (i2c->state == STATE_READ)
424 goto prepare_read;
425
426 /*
427 * fall through to the write state, as we will need to
428 * send a byte as well
429 */
430 fallthrough;
431 case STATE_WRITE:
432 /*
433 * we are writing data to the device... check for the
434 * end of the message, and if so, work out what to do
435 */
436 if (!(i2c->msg->flags & I2C_M_IGNORE_NAK)) {
437 if (iicstat & S3C2410_IICSTAT_LASTBIT) {
438 dev_dbg(i2c->dev, "WRITE: No Ack\n");
439
440 s3c24xx_i2c_stop(i2c, ret: -ECONNREFUSED);
441 goto out_ack;
442 }
443 }
444
445 retry_write:
446
447 if (!is_msgend(i2c)) {
448 byte = i2c->msg->buf[i2c->msg_ptr++];
449 writeb(val: byte, addr: i2c->regs + S3C2410_IICDS);
450
451 /*
452 * delay after writing the byte to allow the
453 * data setup time on the bus, as writing the
454 * data to the register causes the first bit
455 * to appear on SDA, and SCL will change as
456 * soon as the interrupt is acknowledged
457 */
458 ndelay(i2c->tx_setup);
459
460 } else if (!is_lastmsg(i2c)) {
461 /* we need to go to the next i2c message */
462
463 dev_dbg(i2c->dev, "WRITE: Next Message\n");
464
465 i2c->msg_ptr = 0;
466 i2c->msg_idx++;
467 i2c->msg++;
468
469 /* check to see if we need to do another message */
470 if (i2c->msg->flags & I2C_M_NOSTART) {
471
472 if (i2c->msg->flags & I2C_M_RD) {
473 /*
474 * cannot do this, the controller
475 * forces us to send a new START
476 * when we change direction
477 */
478 dev_dbg(i2c->dev,
479 "missing START before write->read\n");
480 s3c24xx_i2c_stop(i2c, ret: -EINVAL);
481 break;
482 }
483
484 goto retry_write;
485 } else {
486 /* send the new start */
487 s3c24xx_i2c_message_start(i2c, msg: i2c->msg);
488 i2c->state = STATE_START;
489 }
490
491 } else {
492 /* send stop */
493 s3c24xx_i2c_stop(i2c, ret: 0);
494 }
495 break;
496
497 case STATE_READ:
498 /*
499 * we have a byte of data in the data register, do
500 * something with it, and then work out whether we are
501 * going to do any more read/write
502 */
503 byte = readb(addr: i2c->regs + S3C2410_IICDS);
504 i2c->msg->buf[i2c->msg_ptr++] = byte;
505
506 /* Add actual length to read for smbus block read */
507 if (i2c->msg->flags & I2C_M_RECV_LEN && i2c->msg->len == 1)
508 i2c->msg->len += byte;
509 prepare_read:
510 if (is_msglast(i2c)) {
511 /* last byte of buffer */
512
513 if (is_lastmsg(i2c))
514 s3c24xx_i2c_disable_ack(i2c);
515
516 } else if (is_msgend(i2c)) {
517 /*
518 * ok, we've read the entire buffer, see if there
519 * is anything else we need to do
520 */
521 if (is_lastmsg(i2c)) {
522 /* last message, send stop and complete */
523 dev_dbg(i2c->dev, "READ: Send Stop\n");
524
525 s3c24xx_i2c_stop(i2c, ret: 0);
526 } else {
527 /* go to the next transfer */
528 dev_dbg(i2c->dev, "READ: Next Transfer\n");
529
530 i2c->msg_ptr = 0;
531 i2c->msg_idx++;
532 i2c->msg++;
533 }
534 }
535
536 break;
537 }
538
539 /* acknowlegde the IRQ and get back on with the work */
540
541 out_ack:
542 tmp = readl(addr: i2c->regs + S3C2410_IICCON);
543 tmp &= ~S3C2410_IICCON_IRQPEND;
544 writel(val: tmp, addr: i2c->regs + S3C2410_IICCON);
545 out:
546 return;
547}
548
549/*
550 * top level IRQ servicing routine
551 */
552static irqreturn_t s3c24xx_i2c_irq(int irqno, void *dev_id)
553{
554 struct s3c24xx_i2c *i2c = dev_id;
555 unsigned long status;
556 unsigned long tmp;
557
558 status = readl(addr: i2c->regs + S3C2410_IICSTAT);
559
560 if (status & S3C2410_IICSTAT_ARBITR) {
561 /* deal with arbitration loss */
562 dev_err(i2c->dev, "deal with arbitration loss\n");
563 }
564
565 if (i2c->state == STATE_IDLE) {
566 dev_dbg(i2c->dev, "IRQ: error i2c->state == IDLE\n");
567
568 tmp = readl(addr: i2c->regs + S3C2410_IICCON);
569 tmp &= ~S3C2410_IICCON_IRQPEND;
570 writel(val: tmp, addr: i2c->regs + S3C2410_IICCON);
571 goto out;
572 }
573
574 /*
575 * pretty much this leaves us with the fact that we've
576 * transmitted or received whatever byte we last sent
577 */
578 i2c_s3c_irq_nextbyte(i2c, iicstat: status);
579
580 out:
581 return IRQ_HANDLED;
582}
583
584/*
585 * Disable the bus so that we won't get any interrupts from now on, or try
586 * to drive any lines. This is the default state when we don't have
587 * anything to send/receive.
588 *
589 * If there is an event on the bus, or we have a pre-existing event at
590 * kernel boot time, we may not notice the event and the I2C controller
591 * will lock the bus with the I2C clock line low indefinitely.
592 */
593static inline void s3c24xx_i2c_disable_bus(struct s3c24xx_i2c *i2c)
594{
595 unsigned long tmp;
596
597 /* Stop driving the I2C pins */
598 tmp = readl(addr: i2c->regs + S3C2410_IICSTAT);
599 tmp &= ~S3C2410_IICSTAT_TXRXEN;
600 writel(val: tmp, addr: i2c->regs + S3C2410_IICSTAT);
601
602 /* We don't expect any interrupts now, and don't want send acks */
603 tmp = readl(addr: i2c->regs + S3C2410_IICCON);
604 tmp &= ~(S3C2410_IICCON_IRQEN | S3C2410_IICCON_IRQPEND |
605 S3C2410_IICCON_ACKEN);
606 writel(val: tmp, addr: i2c->regs + S3C2410_IICCON);
607}
608
609
610/*
611 * get the i2c bus for a master transaction
612 */
613static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
614{
615 unsigned long iicstat;
616 int timeout = 400;
617
618 while (timeout-- > 0) {
619 iicstat = readl(addr: i2c->regs + S3C2410_IICSTAT);
620
621 if (!(iicstat & S3C2410_IICSTAT_BUSBUSY))
622 return 0;
623
624 msleep(msecs: 1);
625 }
626
627 return -ETIMEDOUT;
628}
629
630/*
631 * wait for the i2c bus to become idle.
632 */
633static void s3c24xx_i2c_wait_idle(struct s3c24xx_i2c *i2c)
634{
635 unsigned long iicstat;
636 ktime_t start, now;
637 unsigned long delay;
638 int spins;
639
640 /* ensure the stop has been through the bus */
641
642 dev_dbg(i2c->dev, "waiting for bus idle\n");
643
644 start = now = ktime_get();
645
646 /*
647 * Most of the time, the bus is already idle within a few usec of the
648 * end of a transaction. However, really slow i2c devices can stretch
649 * the clock, delaying STOP generation.
650 *
651 * On slower SoCs this typically happens within a very small number of
652 * instructions so busy wait briefly to avoid scheduling overhead.
653 */
654 spins = 3;
655 iicstat = readl(addr: i2c->regs + S3C2410_IICSTAT);
656 while ((iicstat & S3C2410_IICSTAT_START) && --spins) {
657 cpu_relax();
658 iicstat = readl(addr: i2c->regs + S3C2410_IICSTAT);
659 }
660
661 /*
662 * If we do get an appreciable delay as a compromise between idle
663 * detection latency for the normal, fast case, and system load in the
664 * slow device case, use an exponential back off in the polling loop,
665 * up to 1/10th of the total timeout, then continue to poll at a
666 * constant rate up to the timeout.
667 */
668 delay = 1;
669 while ((iicstat & S3C2410_IICSTAT_START) &&
670 ktime_us_delta(later: now, earlier: start) < S3C2410_IDLE_TIMEOUT) {
671 usleep_range(min: delay, max: 2 * delay);
672 if (delay < S3C2410_IDLE_TIMEOUT / 10)
673 delay <<= 1;
674 now = ktime_get();
675 iicstat = readl(addr: i2c->regs + S3C2410_IICSTAT);
676 }
677
678 if (iicstat & S3C2410_IICSTAT_START)
679 dev_warn(i2c->dev, "timeout waiting for bus idle\n");
680}
681
682/*
683 * this starts an i2c transfer
684 */
685static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
686 struct i2c_msg *msgs, int num)
687{
688 unsigned long timeout;
689 int ret;
690
691 ret = s3c24xx_i2c_set_master(i2c);
692 if (ret != 0) {
693 dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
694 ret = -EAGAIN;
695 goto out;
696 }
697
698 i2c->msg = msgs;
699 i2c->msg_num = num;
700 i2c->msg_ptr = 0;
701 i2c->msg_idx = 0;
702 i2c->state = STATE_START;
703
704 s3c24xx_i2c_enable_irq(i2c);
705 s3c24xx_i2c_message_start(i2c, msg: msgs);
706
707 if (i2c->quirks & QUIRK_POLL) {
708 ret = i2c->msg_idx;
709
710 if (ret != num)
711 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
712
713 goto out;
714 }
715
716 timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
717
718 ret = i2c->msg_idx;
719
720 /*
721 * Having these next two as dev_err() makes life very
722 * noisy when doing an i2cdetect
723 */
724 if (timeout == 0)
725 dev_dbg(i2c->dev, "timeout\n");
726 else if (ret != num)
727 dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
728
729 /* For QUIRK_HDMIPHY, bus is already disabled */
730 if (i2c->quirks & QUIRK_HDMIPHY)
731 goto out;
732
733 s3c24xx_i2c_wait_idle(i2c);
734
735 s3c24xx_i2c_disable_bus(i2c);
736
737 out:
738 i2c->state = STATE_IDLE;
739
740 return ret;
741}
742
743/*
744 * first port of call from the i2c bus code when an message needs
745 * transferring across the i2c bus.
746 */
747static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
748 struct i2c_msg *msgs, int num)
749{
750 struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
751 int retry;
752 int ret;
753
754 ret = clk_enable(clk: i2c->clk);
755 if (ret)
756 return ret;
757
758 for (retry = 0; retry < adap->retries; retry++) {
759
760 ret = s3c24xx_i2c_doxfer(i2c, msgs, num);
761
762 if (ret != -EAGAIN) {
763 clk_disable(clk: i2c->clk);
764 return ret;
765 }
766
767 dev_dbg(i2c->dev, "Retrying transmission (%d)\n", retry);
768
769 udelay(100);
770 }
771
772 clk_disable(clk: i2c->clk);
773 return -EREMOTEIO;
774}
775
776/* declare our i2c functionality */
777static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
778{
779 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL_ALL | I2C_FUNC_NOSTART |
780 I2C_FUNC_PROTOCOL_MANGLING;
781}
782
783/* i2c bus registration info */
784static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
785 .master_xfer = s3c24xx_i2c_xfer,
786 .functionality = s3c24xx_i2c_func,
787};
788
789/*
790 * return the divisor settings for a given frequency
791 */
792static int s3c24xx_i2c_calcdivisor(unsigned long clkin, unsigned int wanted,
793 unsigned int *div1, unsigned int *divs)
794{
795 unsigned int calc_divs = clkin / wanted;
796 unsigned int calc_div1;
797
798 if (calc_divs > (16*16))
799 calc_div1 = 512;
800 else
801 calc_div1 = 16;
802
803 calc_divs += calc_div1-1;
804 calc_divs /= calc_div1;
805
806 if (calc_divs == 0)
807 calc_divs = 1;
808 if (calc_divs > 17)
809 calc_divs = 17;
810
811 *divs = calc_divs;
812 *div1 = calc_div1;
813
814 return clkin / (calc_divs * calc_div1);
815}
816
817/*
818 * work out a divisor for the user requested frequency setting,
819 * either by the requested frequency, or scanning the acceptable
820 * range of frequencies until something is found
821 */
822static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
823{
824 struct s3c2410_platform_i2c *pdata = i2c->pdata;
825 unsigned long clkin = clk_get_rate(clk: i2c->clk);
826 unsigned int divs, div1;
827 unsigned long target_frequency;
828 u32 iiccon;
829 int freq;
830
831 i2c->clkrate = clkin;
832 clkin /= 1000; /* clkin now in KHz */
833
834 dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency);
835
836 target_frequency = pdata->frequency ?: I2C_MAX_STANDARD_MODE_FREQ;
837
838 target_frequency /= 1000; /* Target frequency now in KHz */
839
840 freq = s3c24xx_i2c_calcdivisor(clkin, wanted: target_frequency, div1: &div1, divs: &divs);
841
842 if (freq > target_frequency) {
843 dev_err(i2c->dev,
844 "Unable to achieve desired frequency %luKHz." \
845 " Lowest achievable %dKHz\n", target_frequency, freq);
846 return -EINVAL;
847 }
848
849 *got = freq;
850
851 iiccon = readl(addr: i2c->regs + S3C2410_IICCON);
852 iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512);
853 iiccon |= (divs-1);
854
855 if (div1 == 512)
856 iiccon |= S3C2410_IICCON_TXDIV_512;
857
858 if (i2c->quirks & QUIRK_POLL)
859 iiccon |= S3C2410_IICCON_SCALE(2);
860
861 writel(val: iiccon, addr: i2c->regs + S3C2410_IICCON);
862
863 if (i2c->quirks & QUIRK_S3C2440) {
864 unsigned long sda_delay;
865
866 if (pdata->sda_delay) {
867 sda_delay = clkin * pdata->sda_delay;
868 sda_delay = DIV_ROUND_UP(sda_delay, 1000000);
869 sda_delay = DIV_ROUND_UP(sda_delay, 5);
870 if (sda_delay > 3)
871 sda_delay = 3;
872 sda_delay |= S3C2410_IICLC_FILTER_ON;
873 } else
874 sda_delay = 0;
875
876 dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay);
877 writel(val: sda_delay, addr: i2c->regs + S3C2440_IICLC);
878 }
879
880 return 0;
881}
882
883#ifdef CONFIG_OF
884static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
885{
886 int i;
887
888 if (i2c->quirks & QUIRK_NO_GPIO)
889 return 0;
890
891 for (i = 0; i < 2; i++) {
892 i2c->gpios[i] = devm_gpiod_get_index(dev: i2c->dev, NULL,
893 idx: i, flags: GPIOD_ASIS);
894 if (IS_ERR(ptr: i2c->gpios[i])) {
895 dev_err(i2c->dev, "i2c gpio invalid at index %d\n", i);
896 return -EINVAL;
897 }
898 }
899 return 0;
900}
901
902#else
903static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
904{
905 return 0;
906}
907#endif
908
909/*
910 * initialise the controller, set the IO lines and frequency
911 */
912static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
913{
914 struct s3c2410_platform_i2c *pdata;
915 unsigned int freq;
916
917 /* get the plafrom data */
918
919 pdata = i2c->pdata;
920
921 /* write slave address */
922
923 writeb(val: pdata->slave_addr, addr: i2c->regs + S3C2410_IICADD);
924
925 dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
926
927 writel(val: 0, addr: i2c->regs + S3C2410_IICCON);
928 writel(val: 0, addr: i2c->regs + S3C2410_IICSTAT);
929
930 /* we need to work out the divisors for the clock... */
931
932 if (s3c24xx_i2c_clockrate(i2c, got: &freq) != 0) {
933 dev_err(i2c->dev, "cannot meet bus frequency required\n");
934 return -EINVAL;
935 }
936
937 /* todo - check that the i2c lines aren't being dragged anywhere */
938
939 dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
940 dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02x\n",
941 readl(i2c->regs + S3C2410_IICCON));
942
943 return 0;
944}
945
946#ifdef CONFIG_OF
947/*
948 * Parse the device tree node and retreive the platform data.
949 */
950static void
951s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
952{
953 struct s3c2410_platform_i2c *pdata = i2c->pdata;
954 int id;
955
956 if (!np)
957 return;
958
959 pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
960 of_property_read_u32(np, propname: "samsung,i2c-sda-delay", out_value: &pdata->sda_delay);
961 of_property_read_u32(np, propname: "samsung,i2c-slave-addr", out_value: &pdata->slave_addr);
962 of_property_read_u32(np, propname: "samsung,i2c-max-bus-freq",
963 out_value: (u32 *)&pdata->frequency);
964 /*
965 * Exynos5's legacy i2c controller and new high speed i2c
966 * controller have muxed interrupt sources. By default the
967 * interrupts for 4-channel HS-I2C controller are enabled.
968 * If nodes for first four channels of legacy i2c controller
969 * are available then re-configure the interrupts via the
970 * system register.
971 */
972 id = of_alias_get_id(np, stem: "i2c");
973 i2c->sysreg = syscon_regmap_lookup_by_phandle(np,
974 property: "samsung,sysreg-phandle");
975 if (IS_ERR(ptr: i2c->sysreg))
976 return;
977
978 regmap_update_bits(map: i2c->sysreg, EXYNOS5_SYS_I2C_CFG, BIT(id), val: 0);
979}
980#else
981static void
982s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c) { }
983#endif
984
985static int s3c24xx_i2c_probe(struct platform_device *pdev)
986{
987 struct s3c24xx_i2c *i2c;
988 struct s3c2410_platform_i2c *pdata = NULL;
989 struct resource *res;
990 int ret;
991
992 if (!pdev->dev.of_node) {
993 pdata = dev_get_platdata(dev: &pdev->dev);
994 if (!pdata) {
995 dev_err(&pdev->dev, "no platform data\n");
996 return -EINVAL;
997 }
998 }
999
1000 i2c = devm_kzalloc(dev: &pdev->dev, size: sizeof(struct s3c24xx_i2c), GFP_KERNEL);
1001 if (!i2c)
1002 return -ENOMEM;
1003
1004 i2c->pdata = devm_kzalloc(dev: &pdev->dev, size: sizeof(*pdata), GFP_KERNEL);
1005 if (!i2c->pdata)
1006 return -ENOMEM;
1007
1008 i2c->quirks = s3c24xx_get_device_quirks(pdev);
1009 i2c->sysreg = ERR_PTR(error: -ENOENT);
1010 if (pdata)
1011 memcpy(i2c->pdata, pdata, sizeof(*pdata));
1012 else
1013 s3c24xx_i2c_parse_dt(np: pdev->dev.of_node, i2c);
1014
1015 strscpy(p: i2c->adap.name, q: "s3c2410-i2c", size: sizeof(i2c->adap.name));
1016 i2c->adap.owner = THIS_MODULE;
1017 i2c->adap.algo = &s3c24xx_i2c_algorithm;
1018 i2c->adap.retries = 2;
1019 i2c->adap.class = I2C_CLASS_DEPRECATED;
1020 i2c->tx_setup = 50;
1021
1022 init_waitqueue_head(&i2c->wait);
1023
1024 /* find the clock and enable it */
1025 i2c->dev = &pdev->dev;
1026 i2c->clk = devm_clk_get(dev: &pdev->dev, id: "i2c");
1027 if (IS_ERR(ptr: i2c->clk)) {
1028 dev_err(&pdev->dev, "cannot get clock\n");
1029 return -ENOENT;
1030 }
1031
1032 dev_dbg(&pdev->dev, "clock source %p\n", i2c->clk);
1033
1034 /* map the registers */
1035 i2c->regs = devm_platform_get_and_ioremap_resource(pdev, index: 0, res: &res);
1036 if (IS_ERR(ptr: i2c->regs))
1037 return PTR_ERR(ptr: i2c->regs);
1038
1039 dev_dbg(&pdev->dev, "registers %p (%p)\n",
1040 i2c->regs, res);
1041
1042 /* setup info block for the i2c core */
1043 i2c->adap.algo_data = i2c;
1044 i2c->adap.dev.parent = &pdev->dev;
1045 i2c->pctrl = devm_pinctrl_get_select_default(dev: i2c->dev);
1046
1047 /* inititalise the i2c gpio lines */
1048 if (i2c->pdata->cfg_gpio)
1049 i2c->pdata->cfg_gpio(to_platform_device(i2c->dev));
1050 else if (IS_ERR(ptr: i2c->pctrl) && s3c24xx_i2c_parse_dt_gpio(i2c))
1051 return -EINVAL;
1052
1053 /* initialise the i2c controller */
1054 ret = clk_prepare_enable(clk: i2c->clk);
1055 if (ret) {
1056 dev_err(&pdev->dev, "I2C clock enable failed\n");
1057 return ret;
1058 }
1059
1060 ret = s3c24xx_i2c_init(i2c);
1061 clk_disable(clk: i2c->clk);
1062 if (ret != 0) {
1063 dev_err(&pdev->dev, "I2C controller init failed\n");
1064 clk_unprepare(clk: i2c->clk);
1065 return ret;
1066 }
1067
1068 /*
1069 * find the IRQ for this unit (note, this relies on the init call to
1070 * ensure no current IRQs pending
1071 */
1072 if (!(i2c->quirks & QUIRK_POLL)) {
1073 i2c->irq = ret = platform_get_irq(pdev, 0);
1074 if (ret < 0) {
1075 clk_unprepare(clk: i2c->clk);
1076 return ret;
1077 }
1078
1079 ret = devm_request_irq(dev: &pdev->dev, irq: i2c->irq, handler: s3c24xx_i2c_irq,
1080 irqflags: 0, devname: dev_name(dev: &pdev->dev), dev_id: i2c);
1081 if (ret != 0) {
1082 dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
1083 clk_unprepare(clk: i2c->clk);
1084 return ret;
1085 }
1086 }
1087
1088 /*
1089 * Note, previous versions of the driver used i2c_add_adapter()
1090 * to add the bus at any number. We now pass the bus number via
1091 * the platform data, so if unset it will now default to always
1092 * being bus 0.
1093 */
1094 i2c->adap.nr = i2c->pdata->bus_num;
1095 i2c->adap.dev.of_node = pdev->dev.of_node;
1096
1097 platform_set_drvdata(pdev, data: i2c);
1098
1099 pm_runtime_enable(dev: &pdev->dev);
1100
1101 ret = i2c_add_numbered_adapter(adap: &i2c->adap);
1102 if (ret < 0) {
1103 pm_runtime_disable(dev: &pdev->dev);
1104 clk_unprepare(clk: i2c->clk);
1105 return ret;
1106 }
1107
1108 dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
1109 return 0;
1110}
1111
1112static void s3c24xx_i2c_remove(struct platform_device *pdev)
1113{
1114 struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
1115
1116 clk_unprepare(clk: i2c->clk);
1117
1118 pm_runtime_disable(dev: &pdev->dev);
1119
1120 i2c_del_adapter(adap: &i2c->adap);
1121}
1122
1123static int s3c24xx_i2c_suspend_noirq(struct device *dev)
1124{
1125 struct s3c24xx_i2c *i2c = dev_get_drvdata(dev);
1126
1127 i2c_mark_adapter_suspended(adap: &i2c->adap);
1128
1129 if (!IS_ERR(ptr: i2c->sysreg))
1130 regmap_read(map: i2c->sysreg, EXYNOS5_SYS_I2C_CFG, val: &i2c->sys_i2c_cfg);
1131
1132 return 0;
1133}
1134
1135static int s3c24xx_i2c_resume_noirq(struct device *dev)
1136{
1137 struct s3c24xx_i2c *i2c = dev_get_drvdata(dev);
1138 int ret;
1139
1140 if (!IS_ERR(ptr: i2c->sysreg))
1141 regmap_write(map: i2c->sysreg, EXYNOS5_SYS_I2C_CFG, val: i2c->sys_i2c_cfg);
1142
1143 ret = clk_enable(clk: i2c->clk);
1144 if (ret)
1145 return ret;
1146 s3c24xx_i2c_init(i2c);
1147 clk_disable(clk: i2c->clk);
1148 i2c_mark_adapter_resumed(adap: &i2c->adap);
1149
1150 return 0;
1151}
1152
1153static const struct dev_pm_ops s3c24xx_i2c_dev_pm_ops = {
1154 NOIRQ_SYSTEM_SLEEP_PM_OPS(s3c24xx_i2c_suspend_noirq,
1155 s3c24xx_i2c_resume_noirq)
1156};
1157
1158static struct platform_driver s3c24xx_i2c_driver = {
1159 .probe = s3c24xx_i2c_probe,
1160 .remove_new = s3c24xx_i2c_remove,
1161 .id_table = s3c24xx_driver_ids,
1162 .driver = {
1163 .name = "s3c-i2c",
1164 .pm = pm_sleep_ptr(&s3c24xx_i2c_dev_pm_ops),
1165 .of_match_table = of_match_ptr(s3c24xx_i2c_match),
1166 },
1167};
1168
1169static int __init i2c_adap_s3c_init(void)
1170{
1171 return platform_driver_register(&s3c24xx_i2c_driver);
1172}
1173subsys_initcall(i2c_adap_s3c_init);
1174
1175static void __exit i2c_adap_s3c_exit(void)
1176{
1177 platform_driver_unregister(&s3c24xx_i2c_driver);
1178}
1179module_exit(i2c_adap_s3c_exit);
1180
1181MODULE_DESCRIPTION("S3C24XX I2C Bus driver");
1182MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
1183MODULE_LICENSE("GPL");
1184

source code of linux/drivers/i2c/busses/i2c-s3c2410.c