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1/*
2 * TI DAVINCI I2C adapter driver.
3 *
4 * Copyright (C) 2006 Texas Instruments.
5 * Copyright (C) 2007 MontaVista Software Inc.
6 *
7 * Updated by Vinod & Sudhakar Feb 2005
8 *
9 * ----------------------------------------------------------------------------
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 * ----------------------------------------------------------------------------
25 *
26 */
27#include <linux/kernel.h>
28#include <linux/module.h>
29#include <linux/delay.h>
30#include <linux/i2c.h>
31#include <linux/clk.h>
32#include <linux/errno.h>
33#include <linux/sched.h>
34#include <linux/err.h>
35#include <linux/interrupt.h>
36#include <linux/platform_device.h>
37#include <linux/io.h>
38#include <linux/slab.h>
39#include <linux/cpufreq.h>
40#include <linux/gpio.h>
41
42#include <mach/hardware.h>
43#include <mach/i2c.h>
44
45/* ----- global defines ----------------------------------------------- */
46
47#define DAVINCI_I2C_TIMEOUT (1*HZ)
48#define DAVINCI_I2C_MAX_TRIES 2
49#define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_AAS | \
50 DAVINCI_I2C_IMR_SCD | \
51 DAVINCI_I2C_IMR_ARDY | \
52 DAVINCI_I2C_IMR_NACK | \
53 DAVINCI_I2C_IMR_AL)
54
55#define DAVINCI_I2C_OAR_REG 0x00
56#define DAVINCI_I2C_IMR_REG 0x04
57#define DAVINCI_I2C_STR_REG 0x08
58#define DAVINCI_I2C_CLKL_REG 0x0c
59#define DAVINCI_I2C_CLKH_REG 0x10
60#define DAVINCI_I2C_CNT_REG 0x14
61#define DAVINCI_I2C_DRR_REG 0x18
62#define DAVINCI_I2C_SAR_REG 0x1c
63#define DAVINCI_I2C_DXR_REG 0x20
64#define DAVINCI_I2C_MDR_REG 0x24
65#define DAVINCI_I2C_IVR_REG 0x28
66#define DAVINCI_I2C_EMDR_REG 0x2c
67#define DAVINCI_I2C_PSC_REG 0x30
68
69#define DAVINCI_I2C_IVR_AAS 0x07
70#define DAVINCI_I2C_IVR_SCD 0x06
71#define DAVINCI_I2C_IVR_XRDY 0x05
72#define DAVINCI_I2C_IVR_RDR 0x04
73#define DAVINCI_I2C_IVR_ARDY 0x03
74#define DAVINCI_I2C_IVR_NACK 0x02
75#define DAVINCI_I2C_IVR_AL 0x01
76
77#define DAVINCI_I2C_STR_BB BIT(12)
78#define DAVINCI_I2C_STR_RSFULL BIT(11)
79#define DAVINCI_I2C_STR_SCD BIT(5)
80#define DAVINCI_I2C_STR_ARDY BIT(2)
81#define DAVINCI_I2C_STR_NACK BIT(1)
82#define DAVINCI_I2C_STR_AL BIT(0)
83
84#define DAVINCI_I2C_MDR_NACK BIT(15)
85#define DAVINCI_I2C_MDR_STT BIT(13)
86#define DAVINCI_I2C_MDR_STP BIT(11)
87#define DAVINCI_I2C_MDR_MST BIT(10)
88#define DAVINCI_I2C_MDR_TRX BIT(9)
89#define DAVINCI_I2C_MDR_XA BIT(8)
90#define DAVINCI_I2C_MDR_RM BIT(7)
91#define DAVINCI_I2C_MDR_IRS BIT(5)
92
93#define DAVINCI_I2C_IMR_AAS BIT(6)
94#define DAVINCI_I2C_IMR_SCD BIT(5)
95#define DAVINCI_I2C_IMR_XRDY BIT(4)
96#define DAVINCI_I2C_IMR_RRDY BIT(3)
97#define DAVINCI_I2C_IMR_ARDY BIT(2)
98#define DAVINCI_I2C_IMR_NACK BIT(1)
99#define DAVINCI_I2C_IMR_AL BIT(0)
100
101struct davinci_i2c_dev {
102 struct device *dev;
103 void __iomem *base;
104 struct completion cmd_complete;
105 struct clk *clk;
106 int cmd_err;
107 u8 *buf;
108 size_t buf_len;
109 int irq;
110 int stop;
111 u8 terminate;
112 struct i2c_adapter adapter;
113#ifdef CONFIG_CPU_FREQ
114 struct completion xfr_complete;
115 struct notifier_block freq_transition;
116#endif
117};
118
119/* default platform data to use if not supplied in the platform_device */
120static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
121 .bus_freq = 100,
122 .bus_delay = 0,
123};
124
125static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
126 int reg, u16 val)
127{
128 __raw_writew(val, i2c_dev->base + reg);
129}
130
131static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
132{
133 return __raw_readw(i2c_dev->base + reg);
134}
135
136/* Generate a pulse on the i2c clock pin. */
137static void generic_i2c_clock_pulse(unsigned int scl_pin)
138{
139 u16 i;
140
141 if (scl_pin) {
142 /* Send high and low on the SCL line */
143 for (i = 0; i < 9; i++) {
144 gpio_set_value(scl_pin, 0);
145 udelay(20);
146 gpio_set_value(scl_pin, 1);
147 udelay(20);
148 }
149 }
150}
151
152/* This routine does i2c bus recovery as specified in the
153 * i2c protocol Rev. 03 section 3.16 titled "Bus clear"
154 */
155static void i2c_recover_bus(struct davinci_i2c_dev *dev)
156{
157 u32 flag = 0;
158 struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
159
160 dev_err(dev->dev, "initiating i2c bus recovery\n");
161 /* Send NACK to the slave */
162 flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
163 flag |= DAVINCI_I2C_MDR_NACK;
164 /* write the data into mode register */
165 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
166 if (pdata)
167 generic_i2c_clock_pulse(pdata->scl_pin);
168 /* Send STOP */
169 flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
170 flag |= DAVINCI_I2C_MDR_STP;
171 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
172}
173
174static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
175 int val)
176{
177 u16 w;
178
179 w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG);
180 if (!val) /* put I2C into reset */
181 w &= ~DAVINCI_I2C_MDR_IRS;
182 else /* take I2C out of reset */
183 w |= DAVINCI_I2C_MDR_IRS;
184
185 davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w);
186}
187
188static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
189{
190 struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
191 u16 psc;
192 u32 clk;
193 u32 d;
194 u32 clkh;
195 u32 clkl;
196 u32 input_clock = clk_get_rate(dev->clk);
197
198 /* NOTE: I2C Clock divider programming info
199 * As per I2C specs the following formulas provide prescaler
200 * and low/high divider values
201 * input clk --> PSC Div -----------> ICCL/H Div --> output clock
202 * module clk
203 *
204 * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
205 *
206 * Thus,
207 * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
208 *
209 * where if PSC == 0, d = 7,
210 * if PSC == 1, d = 6
211 * if PSC > 1 , d = 5
212 */
213
214 /* get minimum of 7 MHz clock, but max of 12 MHz */
215 psc = (input_clock / 7000000) - 1;
216 if ((input_clock / (psc + 1)) > 12000000)
217 psc++; /* better to run under spec than over */
218 d = (psc >= 2) ? 5 : 7 - psc;
219
220 clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1);
221 clkh = clk >> 1;
222 clkl = clk - clkh;
223
224 davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
225 davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
226 davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
227
228 dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
229}
230
231/*
232 * This function configures I2C and brings I2C out of reset.
233 * This function is called during I2C init function. This function
234 * also gets called if I2C encounters any errors.
235 */
236static int i2c_davinci_init(struct davinci_i2c_dev *dev)
237{
238 struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
239
240 if (!pdata)
241 pdata = &davinci_i2c_platform_data_default;
242
243 /* put I2C into reset */
244 davinci_i2c_reset_ctrl(dev, 0);
245
246 /* compute clock dividers */
247 i2c_davinci_calc_clk_dividers(dev);
248
249 /* Respond at reserved "SMBus Host" slave address" (and zero);
250 * we seem to have no option to not respond...
251 */
252 davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08);
253
254 dev_dbg(dev->dev, "PSC = %d\n",
255 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
256 dev_dbg(dev->dev, "CLKL = %d\n",
257 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
258 dev_dbg(dev->dev, "CLKH = %d\n",
259 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
260 dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
261 pdata->bus_freq, pdata->bus_delay);
262
263 /* Take the I2C module out of reset: */
264 davinci_i2c_reset_ctrl(dev, 1);
265
266 /* Enable interrupts */
267 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
268
269 return 0;
270}
271
272/*
273 * Waiting for bus not busy
274 */
275static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
276 char allow_sleep)
277{
278 unsigned long timeout;
279 static u16 to_cnt;
280
281 timeout = jiffies + dev->adapter.timeout;
282 while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
283 & DAVINCI_I2C_STR_BB) {
284 if (to_cnt <= DAVINCI_I2C_MAX_TRIES) {
285 if (time_after(jiffies, timeout)) {
286 dev_warn(dev->dev,
287 "timeout waiting for bus ready\n");
288 to_cnt++;
289 return -ETIMEDOUT;
290 } else {
291 to_cnt = 0;
292 i2c_recover_bus(dev);
293 i2c_davinci_init(dev);
294 }
295 }
296 if (allow_sleep)
297 schedule_timeout(1);
298 }
299
300 return 0;
301}
302
303/*
304 * Low level master read/write transaction. This function is called
305 * from i2c_davinci_xfer.
306 */
307static int
308i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
309{
310 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
311 struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
312 u32 flag;
313 u16 w;
314 int r;
315
316 if (!pdata)
317 pdata = &davinci_i2c_platform_data_default;
318 /* Introduce a delay, required for some boards (e.g Davinci EVM) */
319 if (pdata->bus_delay)
320 udelay(pdata->bus_delay);
321
322 /* set the slave address */
323 davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
324
325 dev->buf = msg->buf;
326 dev->buf_len = msg->len;
327 dev->stop = stop;
328
329 davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
330
331 INIT_COMPLETION(dev->cmd_complete);
332 dev->cmd_err = 0;
333
334 /* Take I2C out of reset and configure it as master */
335 flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST;
336
337 /* if the slave address is ten bit address, enable XA bit */
338 if (msg->flags & I2C_M_TEN)
339 flag |= DAVINCI_I2C_MDR_XA;
340 if (!(msg->flags & I2C_M_RD))
341 flag |= DAVINCI_I2C_MDR_TRX;
342 if (msg->len == 0)
343 flag |= DAVINCI_I2C_MDR_RM;
344
345 /* Enable receive or transmit interrupts */
346 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
347 if (msg->flags & I2C_M_RD)
348 w |= DAVINCI_I2C_IMR_RRDY;
349 else
350 w |= DAVINCI_I2C_IMR_XRDY;
351 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
352
353 dev->terminate = 0;
354
355 /*
356 * Write mode register first as needed for correct behaviour
357 * on OMAP-L138, but don't set STT yet to avoid a race with XRDY
358 * occurring before we have loaded DXR
359 */
360 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
361
362 /*
363 * First byte should be set here, not after interrupt,
364 * because transmit-data-ready interrupt can come before
365 * NACK-interrupt during sending of previous message and
366 * ICDXR may have wrong data
367 * It also saves us one interrupt, slightly faster
368 */
369 if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
370 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
371 dev->buf_len--;
372 }
373
374 /* Set STT to begin transmit now DXR is loaded */
375 flag |= DAVINCI_I2C_MDR_STT;
376 if (stop && msg->len != 0)
377 flag |= DAVINCI_I2C_MDR_STP;
378 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
379
380 r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
381 dev->adapter.timeout);
382 if (r == 0) {
383 dev_err(dev->dev, "controller timed out\n");
384 i2c_recover_bus(dev);
385 i2c_davinci_init(dev);
386 dev->buf_len = 0;
387 return -ETIMEDOUT;
388 }
389 if (dev->buf_len) {
390 /* This should be 0 if all bytes were transferred
391 * or dev->cmd_err denotes an error.
392 * A signal may have aborted the transfer.
393 */
394 if (r >= 0) {
395 dev_err(dev->dev, "abnormal termination buf_len=%i\n",
396 dev->buf_len);
397 r = -EREMOTEIO;
398 }
399 dev->terminate = 1;
400 wmb();
401 dev->buf_len = 0;
402 }
403 if (r < 0)
404 return r;
405
406 /* no error */
407 if (likely(!dev->cmd_err))
408 return msg->len;
409
410 /* We have an error */
411 if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
412 i2c_davinci_init(dev);
413 return -EIO;
414 }
415
416 if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
417 if (msg->flags & I2C_M_IGNORE_NAK)
418 return msg->len;
419 if (stop) {
420 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
421 w |= DAVINCI_I2C_MDR_STP;
422 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
423 }
424 return -EREMOTEIO;
425 }
426 return -EIO;
427}
428
429/*
430 * Prepare controller for a transaction and call i2c_davinci_xfer_msg
431 */
432static int
433i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
434{
435 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
436 int i;
437 int ret;
438
439 dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
440
441 ret = i2c_davinci_wait_bus_not_busy(dev, 1);
442 if (ret < 0) {
443 dev_warn(dev->dev, "timeout waiting for bus ready\n");
444 return ret;
445 }
446
447 for (i = 0; i < num; i++) {
448 ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
449 dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
450 ret);
451 if (ret < 0)
452 return ret;
453 }
454
455#ifdef CONFIG_CPU_FREQ
456 complete(&dev->xfr_complete);
457#endif
458
459 return num;
460}
461
462static u32 i2c_davinci_func(struct i2c_adapter *adap)
463{
464 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
465}
466
467static void terminate_read(struct davinci_i2c_dev *dev)
468{
469 u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
470 w |= DAVINCI_I2C_MDR_NACK;
471 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
472
473 /* Throw away data */
474 davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG);
475 if (!dev->terminate)
476 dev_err(dev->dev, "RDR IRQ while no data requested\n");
477}
478static void terminate_write(struct davinci_i2c_dev *dev)
479{
480 u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
481 w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP;
482 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
483
484 if (!dev->terminate)
485 dev_dbg(dev->dev, "TDR IRQ while no data to send\n");
486}
487
488/*
489 * Interrupt service routine. This gets called whenever an I2C interrupt
490 * occurs.
491 */
492static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
493{
494 struct davinci_i2c_dev *dev = dev_id;
495 u32 stat;
496 int count = 0;
497 u16 w;
498
499 while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
500 dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
501 if (count++ == 100) {
502 dev_warn(dev->dev, "Too much work in one IRQ\n");
503 break;
504 }
505
506 switch (stat) {
507 case DAVINCI_I2C_IVR_AL:
508 /* Arbitration lost, must retry */
509 dev->cmd_err |= DAVINCI_I2C_STR_AL;
510 dev->buf_len = 0;
511 complete(&dev->cmd_complete);
512 break;
513
514 case DAVINCI_I2C_IVR_NACK:
515 dev->cmd_err |= DAVINCI_I2C_STR_NACK;
516 dev->buf_len = 0;
517 complete(&dev->cmd_complete);
518 break;
519
520 case DAVINCI_I2C_IVR_ARDY:
521 davinci_i2c_write_reg(dev,
522 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
523 if (((dev->buf_len == 0) && (dev->stop != 0)) ||
524 (dev->cmd_err & DAVINCI_I2C_STR_NACK)) {
525 w = davinci_i2c_read_reg(dev,
526 DAVINCI_I2C_MDR_REG);
527 w |= DAVINCI_I2C_MDR_STP;
528 davinci_i2c_write_reg(dev,
529 DAVINCI_I2C_MDR_REG, w);
530 }
531 complete(&dev->cmd_complete);
532 break;
533
534 case DAVINCI_I2C_IVR_RDR:
535 if (dev->buf_len) {
536 *dev->buf++ =
537 davinci_i2c_read_reg(dev,
538 DAVINCI_I2C_DRR_REG);
539 dev->buf_len--;
540 if (dev->buf_len)
541 continue;
542
543 davinci_i2c_write_reg(dev,
544 DAVINCI_I2C_STR_REG,
545 DAVINCI_I2C_IMR_RRDY);
546 } else {
547 /* signal can terminate transfer */
548 terminate_read(dev);
549 }
550 break;
551
552 case DAVINCI_I2C_IVR_XRDY:
553 if (dev->buf_len) {
554 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
555 *dev->buf++);
556 dev->buf_len--;
557 if (dev->buf_len)
558 continue;
559
560 w = davinci_i2c_read_reg(dev,
561 DAVINCI_I2C_IMR_REG);
562 w &= ~DAVINCI_I2C_IMR_XRDY;
563 davinci_i2c_write_reg(dev,
564 DAVINCI_I2C_IMR_REG,
565 w);
566 } else {
567 /* signal can terminate transfer */
568 terminate_write(dev);
569 }
570 break;
571
572 case DAVINCI_I2C_IVR_SCD:
573 davinci_i2c_write_reg(dev,
574 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
575 complete(&dev->cmd_complete);
576 break;
577
578 case DAVINCI_I2C_IVR_AAS:
579 dev_dbg(dev->dev, "Address as slave interrupt\n");
580 break;
581
582 default:
583 dev_warn(dev->dev, "Unrecognized irq stat %d\n", stat);
584 break;
585 }
586 }
587
588 return count ? IRQ_HANDLED : IRQ_NONE;
589}
590
591#ifdef CONFIG_CPU_FREQ
592static int i2c_davinci_cpufreq_transition(struct notifier_block *nb,
593 unsigned long val, void *data)
594{
595 struct davinci_i2c_dev *dev;
596
597 dev = container_of(nb, struct davinci_i2c_dev, freq_transition);
598 if (val == CPUFREQ_PRECHANGE) {
599 wait_for_completion(&dev->xfr_complete);
600 davinci_i2c_reset_ctrl(dev, 0);
601 } else if (val == CPUFREQ_POSTCHANGE) {
602 i2c_davinci_calc_clk_dividers(dev);
603 davinci_i2c_reset_ctrl(dev, 1);
604 }
605
606 return 0;
607}
608
609static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
610{
611 dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition;
612
613 return cpufreq_register_notifier(&dev->freq_transition,
614 CPUFREQ_TRANSITION_NOTIFIER);
615}
616
617static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
618{
619 cpufreq_unregister_notifier(&dev->freq_transition,
620 CPUFREQ_TRANSITION_NOTIFIER);
621}
622#else
623static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
624{
625 return 0;
626}
627
628static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
629{
630}
631#endif
632
633static struct i2c_algorithm i2c_davinci_algo = {
634 .master_xfer = i2c_davinci_xfer,
635 .functionality = i2c_davinci_func,
636};
637
638static int davinci_i2c_probe(struct platform_device *pdev)
639{
640 struct davinci_i2c_dev *dev;
641 struct i2c_adapter *adap;
642 struct resource *mem, *irq, *ioarea;
643 int r;
644
645 /* NOTE: driver uses the static register mapping */
646 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
647 if (!mem) {
648 dev_err(&pdev->dev, "no mem resource?\n");
649 return -ENODEV;
650 }
651
652 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
653 if (!irq) {
654 dev_err(&pdev->dev, "no irq resource?\n");
655 return -ENODEV;
656 }
657
658 ioarea = request_mem_region(mem->start, resource_size(mem),
659 pdev->name);
660 if (!ioarea) {
661 dev_err(&pdev->dev, "I2C region already claimed\n");
662 return -EBUSY;
663 }
664
665 dev = kzalloc(sizeof(struct davinci_i2c_dev), GFP_KERNEL);
666 if (!dev) {
667 r = -ENOMEM;
668 goto err_release_region;
669 }
670
671 init_completion(&dev->cmd_complete);
672#ifdef CONFIG_CPU_FREQ
673 init_completion(&dev->xfr_complete);
674#endif
675 dev->dev = get_device(&pdev->dev);
676 dev->irq = irq->start;
677 platform_set_drvdata(pdev, dev);
678
679 dev->clk = clk_get(&pdev->dev, NULL);
680 if (IS_ERR(dev->clk)) {
681 r = -ENODEV;
682 goto err_free_mem;
683 }
684 clk_enable(dev->clk);
685
686 dev->base = ioremap(mem->start, resource_size(mem));
687 if (!dev->base) {
688 r = -EBUSY;
689 goto err_mem_ioremap;
690 }
691
692 i2c_davinci_init(dev);
693
694 r = request_irq(dev->irq, i2c_davinci_isr, 0, pdev->name, dev);
695 if (r) {
696 dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
697 goto err_unuse_clocks;
698 }
699
700 r = i2c_davinci_cpufreq_register(dev);
701 if (r) {
702 dev_err(&pdev->dev, "failed to register cpufreq\n");
703 goto err_free_irq;
704 }
705
706 adap = &dev->adapter;
707 i2c_set_adapdata(adap, dev);
708 adap->owner = THIS_MODULE;
709 adap->class = I2C_CLASS_HWMON;
710 strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
711 adap->algo = &i2c_davinci_algo;
712 adap->dev.parent = &pdev->dev;
713 adap->timeout = DAVINCI_I2C_TIMEOUT;
714
715 adap->nr = pdev->id;
716 r = i2c_add_numbered_adapter(adap);
717 if (r) {
718 dev_err(&pdev->dev, "failure adding adapter\n");
719 goto err_free_irq;
720 }
721
722 return 0;
723
724err_free_irq:
725 free_irq(dev->irq, dev);
726err_unuse_clocks:
727 iounmap(dev->base);
728err_mem_ioremap:
729 clk_disable(dev->clk);
730 clk_put(dev->clk);
731 dev->clk = NULL;
732err_free_mem:
733 platform_set_drvdata(pdev, NULL);
734 put_device(&pdev->dev);
735 kfree(dev);
736err_release_region:
737 release_mem_region(mem->start, resource_size(mem));
738
739 return r;
740}
741
742static int davinci_i2c_remove(struct platform_device *pdev)
743{
744 struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
745 struct resource *mem;
746
747 i2c_davinci_cpufreq_deregister(dev);
748
749 platform_set_drvdata(pdev, NULL);
750 i2c_del_adapter(&dev->adapter);
751 put_device(&pdev->dev);
752
753 clk_disable(dev->clk);
754 clk_put(dev->clk);
755 dev->clk = NULL;
756
757 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
758 free_irq(IRQ_I2C, dev);
759 iounmap(dev->base);
760 kfree(dev);
761
762 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
763 release_mem_region(mem->start, resource_size(mem));
764 return 0;
765}
766
767#ifdef CONFIG_PM
768static int davinci_i2c_suspend(struct device *dev)
769{
770 struct platform_device *pdev = to_platform_device(dev);
771 struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
772
773 /* put I2C into reset */
774 davinci_i2c_reset_ctrl(i2c_dev, 0);
775 clk_disable(i2c_dev->clk);
776
777 return 0;
778}
779
780static int davinci_i2c_resume(struct device *dev)
781{
782 struct platform_device *pdev = to_platform_device(dev);
783 struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
784
785 clk_enable(i2c_dev->clk);
786 /* take I2C out of reset */
787 davinci_i2c_reset_ctrl(i2c_dev, 1);
788
789 return 0;
790}
791
792static const struct dev_pm_ops davinci_i2c_pm = {
793 .suspend = davinci_i2c_suspend,
794 .resume = davinci_i2c_resume,
795};
796
797#define davinci_i2c_pm_ops (&davinci_i2c_pm)
798#else
799#define davinci_i2c_pm_ops NULL
800#endif
801
802/* work with hotplug and coldplug */
803MODULE_ALIAS("platform:i2c_davinci");
804
805static struct platform_driver davinci_i2c_driver = {
806 .probe = davinci_i2c_probe,
807 .remove = davinci_i2c_remove,
808 .driver = {
809 .name = "i2c_davinci",
810 .owner = THIS_MODULE,
811 .pm = davinci_i2c_pm_ops,
812 },
813};
814
815/* I2C may be needed to bring up other drivers */
816static int __init davinci_i2c_init_driver(void)
817{
818 return platform_driver_register(&davinci_i2c_driver);
819}
820subsys_initcall(davinci_i2c_init_driver);
821
822static void __exit davinci_i2c_exit_driver(void)
823{
824 platform_driver_unregister(&davinci_i2c_driver);
825}
826module_exit(davinci_i2c_exit_driver);
827
828MODULE_AUTHOR("Texas Instruments India");
829MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
830MODULE_LICENSE("GPL");
1/*
2 * TI DAVINCI I2C adapter driver.
3 *
4 * Copyright (C) 2006 Texas Instruments.
5 * Copyright (C) 2007 MontaVista Software Inc.
6 *
7 * Updated by Vinod & Sudhakar Feb 2005
8 *
9 * ----------------------------------------------------------------------------
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 * ----------------------------------------------------------------------------
21 *
22 */
23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/delay.h>
26#include <linux/i2c.h>
27#include <linux/clk.h>
28#include <linux/errno.h>
29#include <linux/sched.h>
30#include <linux/err.h>
31#include <linux/interrupt.h>
32#include <linux/platform_device.h>
33#include <linux/io.h>
34#include <linux/slab.h>
35#include <linux/cpufreq.h>
36#include <linux/gpio.h>
37#include <linux/of_device.h>
38#include <linux/platform_data/i2c-davinci.h>
39
40/* ----- global defines ----------------------------------------------- */
41
42#define DAVINCI_I2C_TIMEOUT (1*HZ)
43#define DAVINCI_I2C_MAX_TRIES 2
44#define DAVINCI_I2C_OWN_ADDRESS 0x08
45#define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_SCD | \
46 DAVINCI_I2C_IMR_ARDY | \
47 DAVINCI_I2C_IMR_NACK | \
48 DAVINCI_I2C_IMR_AL)
49
50#define DAVINCI_I2C_OAR_REG 0x00
51#define DAVINCI_I2C_IMR_REG 0x04
52#define DAVINCI_I2C_STR_REG 0x08
53#define DAVINCI_I2C_CLKL_REG 0x0c
54#define DAVINCI_I2C_CLKH_REG 0x10
55#define DAVINCI_I2C_CNT_REG 0x14
56#define DAVINCI_I2C_DRR_REG 0x18
57#define DAVINCI_I2C_SAR_REG 0x1c
58#define DAVINCI_I2C_DXR_REG 0x20
59#define DAVINCI_I2C_MDR_REG 0x24
60#define DAVINCI_I2C_IVR_REG 0x28
61#define DAVINCI_I2C_EMDR_REG 0x2c
62#define DAVINCI_I2C_PSC_REG 0x30
63#define DAVINCI_I2C_FUNC_REG 0x48
64#define DAVINCI_I2C_DIR_REG 0x4c
65#define DAVINCI_I2C_DIN_REG 0x50
66#define DAVINCI_I2C_DOUT_REG 0x54
67#define DAVINCI_I2C_DSET_REG 0x58
68#define DAVINCI_I2C_DCLR_REG 0x5c
69
70#define DAVINCI_I2C_IVR_AAS 0x07
71#define DAVINCI_I2C_IVR_SCD 0x06
72#define DAVINCI_I2C_IVR_XRDY 0x05
73#define DAVINCI_I2C_IVR_RDR 0x04
74#define DAVINCI_I2C_IVR_ARDY 0x03
75#define DAVINCI_I2C_IVR_NACK 0x02
76#define DAVINCI_I2C_IVR_AL 0x01
77
78#define DAVINCI_I2C_STR_BB BIT(12)
79#define DAVINCI_I2C_STR_RSFULL BIT(11)
80#define DAVINCI_I2C_STR_SCD BIT(5)
81#define DAVINCI_I2C_STR_ARDY BIT(2)
82#define DAVINCI_I2C_STR_NACK BIT(1)
83#define DAVINCI_I2C_STR_AL BIT(0)
84
85#define DAVINCI_I2C_MDR_NACK BIT(15)
86#define DAVINCI_I2C_MDR_STT BIT(13)
87#define DAVINCI_I2C_MDR_STP BIT(11)
88#define DAVINCI_I2C_MDR_MST BIT(10)
89#define DAVINCI_I2C_MDR_TRX BIT(9)
90#define DAVINCI_I2C_MDR_XA BIT(8)
91#define DAVINCI_I2C_MDR_RM BIT(7)
92#define DAVINCI_I2C_MDR_IRS BIT(5)
93
94#define DAVINCI_I2C_IMR_AAS BIT(6)
95#define DAVINCI_I2C_IMR_SCD BIT(5)
96#define DAVINCI_I2C_IMR_XRDY BIT(4)
97#define DAVINCI_I2C_IMR_RRDY BIT(3)
98#define DAVINCI_I2C_IMR_ARDY BIT(2)
99#define DAVINCI_I2C_IMR_NACK BIT(1)
100#define DAVINCI_I2C_IMR_AL BIT(0)
101
102/* set SDA and SCL as GPIO */
103#define DAVINCI_I2C_FUNC_PFUNC0 BIT(0)
104
105/* set SCL as output when used as GPIO*/
106#define DAVINCI_I2C_DIR_PDIR0 BIT(0)
107/* set SDA as output when used as GPIO*/
108#define DAVINCI_I2C_DIR_PDIR1 BIT(1)
109
110/* read SCL GPIO level */
111#define DAVINCI_I2C_DIN_PDIN0 BIT(0)
112/* read SDA GPIO level */
113#define DAVINCI_I2C_DIN_PDIN1 BIT(1)
114
115/*set the SCL GPIO high */
116#define DAVINCI_I2C_DSET_PDSET0 BIT(0)
117/*set the SDA GPIO high */
118#define DAVINCI_I2C_DSET_PDSET1 BIT(1)
119
120/* set the SCL GPIO low */
121#define DAVINCI_I2C_DCLR_PDCLR0 BIT(0)
122/* set the SDA GPIO low */
123#define DAVINCI_I2C_DCLR_PDCLR1 BIT(1)
124
125struct davinci_i2c_dev {
126 struct device *dev;
127 void __iomem *base;
128 struct completion cmd_complete;
129 struct clk *clk;
130 int cmd_err;
131 u8 *buf;
132 size_t buf_len;
133 int irq;
134 int stop;
135 u8 terminate;
136 struct i2c_adapter adapter;
137#ifdef CONFIG_CPU_FREQ
138 struct completion xfr_complete;
139 struct notifier_block freq_transition;
140#endif
141 struct davinci_i2c_platform_data *pdata;
142};
143
144/* default platform data to use if not supplied in the platform_device */
145static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
146 .bus_freq = 100,
147 .bus_delay = 0,
148};
149
150static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
151 int reg, u16 val)
152{
153 writew_relaxed(val, i2c_dev->base + reg);
154}
155
156static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
157{
158 return readw_relaxed(i2c_dev->base + reg);
159}
160
161static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
162 int val)
163{
164 u16 w;
165
166 w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG);
167 if (!val) /* put I2C into reset */
168 w &= ~DAVINCI_I2C_MDR_IRS;
169 else /* take I2C out of reset */
170 w |= DAVINCI_I2C_MDR_IRS;
171
172 davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w);
173}
174
175static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
176{
177 struct davinci_i2c_platform_data *pdata = dev->pdata;
178 u16 psc;
179 u32 clk;
180 u32 d;
181 u32 clkh;
182 u32 clkl;
183 u32 input_clock = clk_get_rate(dev->clk);
184 struct device_node *of_node = dev->dev->of_node;
185
186 /* NOTE: I2C Clock divider programming info
187 * As per I2C specs the following formulas provide prescaler
188 * and low/high divider values
189 * input clk --> PSC Div -----------> ICCL/H Div --> output clock
190 * module clk
191 *
192 * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
193 *
194 * Thus,
195 * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
196 *
197 * where if PSC == 0, d = 7,
198 * if PSC == 1, d = 6
199 * if PSC > 1 , d = 5
200 *
201 * Note:
202 * d is always 6 on Keystone I2C controller
203 */
204
205 /*
206 * Both Davinci and current Keystone User Guides recommend a value
207 * between 7MHz and 12MHz. In reality 7MHz module clock doesn't
208 * always produce enough margin between SDA and SCL transitions.
209 * Measurements show that the higher the module clock is, the
210 * bigger is the margin, providing more reliable communication.
211 * So we better target for 12MHz.
212 */
213 psc = (input_clock / 12000000) - 1;
214 if ((input_clock / (psc + 1)) > 12000000)
215 psc++; /* better to run under spec than over */
216 d = (psc >= 2) ? 5 : 7 - psc;
217
218 if (of_node && of_device_is_compatible(of_node, "ti,keystone-i2c"))
219 d = 6;
220
221 clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000));
222 /* Avoid driving the bus too fast because of rounding errors above */
223 if (input_clock / (psc + 1) / clk > pdata->bus_freq * 1000)
224 clk++;
225 /*
226 * According to I2C-BUS Spec 2.1, in FAST-MODE LOW period should be at
227 * least 1.3uS, which is not the case with 50% duty cycle. Driving HIGH
228 * to LOW ratio as 1 to 2 is more safe.
229 */
230 if (pdata->bus_freq > 100)
231 clkl = (clk << 1) / 3;
232 else
233 clkl = (clk >> 1);
234 /*
235 * It's not always possible to have 1 to 2 ratio when d=7, so fall back
236 * to minimal possible clkh in this case.
237 */
238 if (clk >= clkl + d) {
239 clkh = clk - clkl - d;
240 clkl -= d;
241 } else {
242 clkh = 0;
243 clkl = clk - (d << 1);
244 }
245
246 davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
247 davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
248 davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
249
250 dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
251}
252
253/*
254 * This function configures I2C and brings I2C out of reset.
255 * This function is called during I2C init function. This function
256 * also gets called if I2C encounters any errors.
257 */
258static int i2c_davinci_init(struct davinci_i2c_dev *dev)
259{
260 struct davinci_i2c_platform_data *pdata = dev->pdata;
261
262 /* put I2C into reset */
263 davinci_i2c_reset_ctrl(dev, 0);
264
265 /* compute clock dividers */
266 i2c_davinci_calc_clk_dividers(dev);
267
268 /* Respond at reserved "SMBus Host" slave address" (and zero);
269 * we seem to have no option to not respond...
270 */
271 davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, DAVINCI_I2C_OWN_ADDRESS);
272
273 dev_dbg(dev->dev, "PSC = %d\n",
274 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
275 dev_dbg(dev->dev, "CLKL = %d\n",
276 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
277 dev_dbg(dev->dev, "CLKH = %d\n",
278 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
279 dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
280 pdata->bus_freq, pdata->bus_delay);
281
282
283 /* Take the I2C module out of reset: */
284 davinci_i2c_reset_ctrl(dev, 1);
285
286 /* Enable interrupts */
287 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
288
289 return 0;
290}
291
292/*
293 * This routine does i2c bus recovery by using i2c_generic_gpio_recovery
294 * which is provided by I2C Bus recovery infrastructure.
295 */
296static void davinci_i2c_prepare_recovery(struct i2c_adapter *adap)
297{
298 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
299
300 /* Disable interrupts */
301 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, 0);
302
303 /* put I2C into reset */
304 davinci_i2c_reset_ctrl(dev, 0);
305}
306
307static void davinci_i2c_unprepare_recovery(struct i2c_adapter *adap)
308{
309 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
310
311 i2c_davinci_init(dev);
312}
313
314static struct i2c_bus_recovery_info davinci_i2c_gpio_recovery_info = {
315 .recover_bus = i2c_generic_gpio_recovery,
316 .prepare_recovery = davinci_i2c_prepare_recovery,
317 .unprepare_recovery = davinci_i2c_unprepare_recovery,
318};
319
320static void davinci_i2c_set_scl(struct i2c_adapter *adap, int val)
321{
322 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
323
324 if (val)
325 davinci_i2c_write_reg(dev, DAVINCI_I2C_DSET_REG,
326 DAVINCI_I2C_DSET_PDSET0);
327 else
328 davinci_i2c_write_reg(dev, DAVINCI_I2C_DCLR_REG,
329 DAVINCI_I2C_DCLR_PDCLR0);
330}
331
332static int davinci_i2c_get_scl(struct i2c_adapter *adap)
333{
334 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
335 int val;
336
337 /* read the state of SCL */
338 val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG);
339 return val & DAVINCI_I2C_DIN_PDIN0;
340}
341
342static int davinci_i2c_get_sda(struct i2c_adapter *adap)
343{
344 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
345 int val;
346
347 /* read the state of SDA */
348 val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG);
349 return val & DAVINCI_I2C_DIN_PDIN1;
350}
351
352static void davinci_i2c_scl_prepare_recovery(struct i2c_adapter *adap)
353{
354 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
355
356 davinci_i2c_prepare_recovery(adap);
357
358 /* SCL output, SDA input */
359 davinci_i2c_write_reg(dev, DAVINCI_I2C_DIR_REG, DAVINCI_I2C_DIR_PDIR0);
360
361 /* change to GPIO mode */
362 davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG,
363 DAVINCI_I2C_FUNC_PFUNC0);
364}
365
366static void davinci_i2c_scl_unprepare_recovery(struct i2c_adapter *adap)
367{
368 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
369
370 /* change back to I2C mode */
371 davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG, 0);
372
373 davinci_i2c_unprepare_recovery(adap);
374}
375
376static struct i2c_bus_recovery_info davinci_i2c_scl_recovery_info = {
377 .recover_bus = i2c_generic_scl_recovery,
378 .set_scl = davinci_i2c_set_scl,
379 .get_scl = davinci_i2c_get_scl,
380 .get_sda = davinci_i2c_get_sda,
381 .prepare_recovery = davinci_i2c_scl_prepare_recovery,
382 .unprepare_recovery = davinci_i2c_scl_unprepare_recovery,
383};
384
385/*
386 * Waiting for bus not busy
387 */
388static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev)
389{
390 unsigned long timeout = jiffies + dev->adapter.timeout;
391
392 do {
393 if (!(davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB))
394 return 0;
395 schedule_timeout_uninterruptible(1);
396 } while (time_before_eq(jiffies, timeout));
397
398 dev_warn(dev->dev, "timeout waiting for bus ready\n");
399 i2c_recover_bus(&dev->adapter);
400
401 /*
402 * if bus is still "busy" here, it's most probably a HW problem like
403 * short-circuit
404 */
405 if (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG) & DAVINCI_I2C_STR_BB)
406 return -EIO;
407
408 return 0;
409}
410
411/*
412 * Low level master read/write transaction. This function is called
413 * from i2c_davinci_xfer.
414 */
415static int
416i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
417{
418 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
419 struct davinci_i2c_platform_data *pdata = dev->pdata;
420 u32 flag;
421 u16 w;
422 unsigned long time_left;
423
424 if (msg->addr == DAVINCI_I2C_OWN_ADDRESS) {
425 dev_warn(dev->dev, "transfer to own address aborted\n");
426 return -EADDRNOTAVAIL;
427 }
428
429 /* Introduce a delay, required for some boards (e.g Davinci EVM) */
430 if (pdata->bus_delay)
431 udelay(pdata->bus_delay);
432
433 /* set the slave address */
434 davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
435
436 dev->buf = msg->buf;
437 dev->buf_len = msg->len;
438 dev->stop = stop;
439
440 davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
441
442 reinit_completion(&dev->cmd_complete);
443 dev->cmd_err = 0;
444
445 /* Take I2C out of reset and configure it as master */
446 flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST;
447
448 /* if the slave address is ten bit address, enable XA bit */
449 if (msg->flags & I2C_M_TEN)
450 flag |= DAVINCI_I2C_MDR_XA;
451 if (!(msg->flags & I2C_M_RD))
452 flag |= DAVINCI_I2C_MDR_TRX;
453 if (msg->len == 0)
454 flag |= DAVINCI_I2C_MDR_RM;
455
456 /* Enable receive or transmit interrupts */
457 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
458 if (msg->flags & I2C_M_RD)
459 w |= DAVINCI_I2C_IMR_RRDY;
460 else
461 w |= DAVINCI_I2C_IMR_XRDY;
462 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
463
464 dev->terminate = 0;
465
466 /*
467 * Write mode register first as needed for correct behaviour
468 * on OMAP-L138, but don't set STT yet to avoid a race with XRDY
469 * occurring before we have loaded DXR
470 */
471 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
472
473 /*
474 * First byte should be set here, not after interrupt,
475 * because transmit-data-ready interrupt can come before
476 * NACK-interrupt during sending of previous message and
477 * ICDXR may have wrong data
478 * It also saves us one interrupt, slightly faster
479 */
480 if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
481 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
482 dev->buf_len--;
483 }
484
485 /* Set STT to begin transmit now DXR is loaded */
486 flag |= DAVINCI_I2C_MDR_STT;
487 if (stop && msg->len != 0)
488 flag |= DAVINCI_I2C_MDR_STP;
489 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
490
491 time_left = wait_for_completion_timeout(&dev->cmd_complete,
492 dev->adapter.timeout);
493 if (!time_left) {
494 dev_err(dev->dev, "controller timed out\n");
495 i2c_recover_bus(adap);
496 dev->buf_len = 0;
497 return -ETIMEDOUT;
498 }
499 if (dev->buf_len) {
500 /* This should be 0 if all bytes were transferred
501 * or dev->cmd_err denotes an error.
502 */
503 dev_err(dev->dev, "abnormal termination buf_len=%i\n",
504 dev->buf_len);
505 dev->terminate = 1;
506 wmb();
507 dev->buf_len = 0;
508 return -EREMOTEIO;
509 }
510
511 /* no error */
512 if (likely(!dev->cmd_err))
513 return msg->len;
514
515 /* We have an error */
516 if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
517 i2c_davinci_init(dev);
518 return -EIO;
519 }
520
521 if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
522 if (msg->flags & I2C_M_IGNORE_NAK)
523 return msg->len;
524 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
525 w |= DAVINCI_I2C_MDR_STP;
526 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
527 return -EREMOTEIO;
528 }
529 return -EIO;
530}
531
532/*
533 * Prepare controller for a transaction and call i2c_davinci_xfer_msg
534 */
535static int
536i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
537{
538 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
539 int i;
540 int ret;
541
542 dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
543
544 ret = i2c_davinci_wait_bus_not_busy(dev);
545 if (ret < 0) {
546 dev_warn(dev->dev, "timeout waiting for bus ready\n");
547 return ret;
548 }
549
550 for (i = 0; i < num; i++) {
551 ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
552 dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
553 ret);
554 if (ret < 0)
555 return ret;
556 }
557
558#ifdef CONFIG_CPU_FREQ
559 complete(&dev->xfr_complete);
560#endif
561
562 return num;
563}
564
565static u32 i2c_davinci_func(struct i2c_adapter *adap)
566{
567 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
568}
569
570static void terminate_read(struct davinci_i2c_dev *dev)
571{
572 u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
573 w |= DAVINCI_I2C_MDR_NACK;
574 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
575
576 /* Throw away data */
577 davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG);
578 if (!dev->terminate)
579 dev_err(dev->dev, "RDR IRQ while no data requested\n");
580}
581static void terminate_write(struct davinci_i2c_dev *dev)
582{
583 u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
584 w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP;
585 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
586
587 if (!dev->terminate)
588 dev_dbg(dev->dev, "TDR IRQ while no data to send\n");
589}
590
591/*
592 * Interrupt service routine. This gets called whenever an I2C interrupt
593 * occurs.
594 */
595static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
596{
597 struct davinci_i2c_dev *dev = dev_id;
598 u32 stat;
599 int count = 0;
600 u16 w;
601
602 while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
603 dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
604 if (count++ == 100) {
605 dev_warn(dev->dev, "Too much work in one IRQ\n");
606 break;
607 }
608
609 switch (stat) {
610 case DAVINCI_I2C_IVR_AL:
611 /* Arbitration lost, must retry */
612 dev->cmd_err |= DAVINCI_I2C_STR_AL;
613 dev->buf_len = 0;
614 complete(&dev->cmd_complete);
615 break;
616
617 case DAVINCI_I2C_IVR_NACK:
618 dev->cmd_err |= DAVINCI_I2C_STR_NACK;
619 dev->buf_len = 0;
620 complete(&dev->cmd_complete);
621 break;
622
623 case DAVINCI_I2C_IVR_ARDY:
624 davinci_i2c_write_reg(dev,
625 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
626 if (((dev->buf_len == 0) && (dev->stop != 0)) ||
627 (dev->cmd_err & DAVINCI_I2C_STR_NACK)) {
628 w = davinci_i2c_read_reg(dev,
629 DAVINCI_I2C_MDR_REG);
630 w |= DAVINCI_I2C_MDR_STP;
631 davinci_i2c_write_reg(dev,
632 DAVINCI_I2C_MDR_REG, w);
633 }
634 complete(&dev->cmd_complete);
635 break;
636
637 case DAVINCI_I2C_IVR_RDR:
638 if (dev->buf_len) {
639 *dev->buf++ =
640 davinci_i2c_read_reg(dev,
641 DAVINCI_I2C_DRR_REG);
642 dev->buf_len--;
643 if (dev->buf_len)
644 continue;
645
646 davinci_i2c_write_reg(dev,
647 DAVINCI_I2C_STR_REG,
648 DAVINCI_I2C_IMR_RRDY);
649 } else {
650 /* signal can terminate transfer */
651 terminate_read(dev);
652 }
653 break;
654
655 case DAVINCI_I2C_IVR_XRDY:
656 if (dev->buf_len) {
657 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
658 *dev->buf++);
659 dev->buf_len--;
660 if (dev->buf_len)
661 continue;
662
663 w = davinci_i2c_read_reg(dev,
664 DAVINCI_I2C_IMR_REG);
665 w &= ~DAVINCI_I2C_IMR_XRDY;
666 davinci_i2c_write_reg(dev,
667 DAVINCI_I2C_IMR_REG,
668 w);
669 } else {
670 /* signal can terminate transfer */
671 terminate_write(dev);
672 }
673 break;
674
675 case DAVINCI_I2C_IVR_SCD:
676 davinci_i2c_write_reg(dev,
677 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
678 complete(&dev->cmd_complete);
679 break;
680
681 case DAVINCI_I2C_IVR_AAS:
682 dev_dbg(dev->dev, "Address as slave interrupt\n");
683 break;
684
685 default:
686 dev_warn(dev->dev, "Unrecognized irq stat %d\n", stat);
687 break;
688 }
689 }
690
691 return count ? IRQ_HANDLED : IRQ_NONE;
692}
693
694#ifdef CONFIG_CPU_FREQ
695static int i2c_davinci_cpufreq_transition(struct notifier_block *nb,
696 unsigned long val, void *data)
697{
698 struct davinci_i2c_dev *dev;
699
700 dev = container_of(nb, struct davinci_i2c_dev, freq_transition);
701 if (val == CPUFREQ_PRECHANGE) {
702 wait_for_completion(&dev->xfr_complete);
703 davinci_i2c_reset_ctrl(dev, 0);
704 } else if (val == CPUFREQ_POSTCHANGE) {
705 i2c_davinci_calc_clk_dividers(dev);
706 davinci_i2c_reset_ctrl(dev, 1);
707 }
708
709 return 0;
710}
711
712static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
713{
714 dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition;
715
716 return cpufreq_register_notifier(&dev->freq_transition,
717 CPUFREQ_TRANSITION_NOTIFIER);
718}
719
720static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
721{
722 cpufreq_unregister_notifier(&dev->freq_transition,
723 CPUFREQ_TRANSITION_NOTIFIER);
724}
725#else
726static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
727{
728 return 0;
729}
730
731static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
732{
733}
734#endif
735
736static struct i2c_algorithm i2c_davinci_algo = {
737 .master_xfer = i2c_davinci_xfer,
738 .functionality = i2c_davinci_func,
739};
740
741static const struct of_device_id davinci_i2c_of_match[] = {
742 {.compatible = "ti,davinci-i2c", },
743 {.compatible = "ti,keystone-i2c", },
744 {},
745};
746MODULE_DEVICE_TABLE(of, davinci_i2c_of_match);
747
748static int davinci_i2c_probe(struct platform_device *pdev)
749{
750 struct davinci_i2c_dev *dev;
751 struct i2c_adapter *adap;
752 struct resource *mem;
753 int r, irq;
754
755 irq = platform_get_irq(pdev, 0);
756 if (irq <= 0) {
757 if (!irq)
758 irq = -ENXIO;
759 if (irq != -EPROBE_DEFER)
760 dev_err(&pdev->dev,
761 "can't get irq resource ret=%d\n", irq);
762 return irq;
763 }
764
765 dev = devm_kzalloc(&pdev->dev, sizeof(struct davinci_i2c_dev),
766 GFP_KERNEL);
767 if (!dev) {
768 dev_err(&pdev->dev, "Memory allocation failed\n");
769 return -ENOMEM;
770 }
771
772 init_completion(&dev->cmd_complete);
773#ifdef CONFIG_CPU_FREQ
774 init_completion(&dev->xfr_complete);
775#endif
776 dev->dev = &pdev->dev;
777 dev->irq = irq;
778 dev->pdata = dev_get_platdata(&pdev->dev);
779 platform_set_drvdata(pdev, dev);
780
781 if (!dev->pdata && pdev->dev.of_node) {
782 u32 prop;
783
784 dev->pdata = devm_kzalloc(&pdev->dev,
785 sizeof(struct davinci_i2c_platform_data), GFP_KERNEL);
786 if (!dev->pdata)
787 return -ENOMEM;
788
789 memcpy(dev->pdata, &davinci_i2c_platform_data_default,
790 sizeof(struct davinci_i2c_platform_data));
791 if (!of_property_read_u32(pdev->dev.of_node, "clock-frequency",
792 &prop))
793 dev->pdata->bus_freq = prop / 1000;
794
795 dev->pdata->has_pfunc =
796 of_property_read_bool(pdev->dev.of_node,
797 "ti,has-pfunc");
798 } else if (!dev->pdata) {
799 dev->pdata = &davinci_i2c_platform_data_default;
800 }
801
802 dev->clk = devm_clk_get(&pdev->dev, NULL);
803 if (IS_ERR(dev->clk))
804 return -ENODEV;
805 clk_prepare_enable(dev->clk);
806
807 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
808 dev->base = devm_ioremap_resource(&pdev->dev, mem);
809 if (IS_ERR(dev->base)) {
810 r = PTR_ERR(dev->base);
811 goto err_unuse_clocks;
812 }
813
814 i2c_davinci_init(dev);
815
816 r = devm_request_irq(&pdev->dev, dev->irq, i2c_davinci_isr, 0,
817 pdev->name, dev);
818 if (r) {
819 dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
820 goto err_unuse_clocks;
821 }
822
823 r = i2c_davinci_cpufreq_register(dev);
824 if (r) {
825 dev_err(&pdev->dev, "failed to register cpufreq\n");
826 goto err_unuse_clocks;
827 }
828
829 adap = &dev->adapter;
830 i2c_set_adapdata(adap, dev);
831 adap->owner = THIS_MODULE;
832 adap->class = I2C_CLASS_DEPRECATED;
833 strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
834 adap->algo = &i2c_davinci_algo;
835 adap->dev.parent = &pdev->dev;
836 adap->timeout = DAVINCI_I2C_TIMEOUT;
837 adap->dev.of_node = pdev->dev.of_node;
838
839 if (dev->pdata->has_pfunc)
840 adap->bus_recovery_info = &davinci_i2c_scl_recovery_info;
841 else if (dev->pdata->scl_pin) {
842 adap->bus_recovery_info = &davinci_i2c_gpio_recovery_info;
843 adap->bus_recovery_info->scl_gpio = dev->pdata->scl_pin;
844 adap->bus_recovery_info->sda_gpio = dev->pdata->sda_pin;
845 }
846
847 adap->nr = pdev->id;
848 r = i2c_add_numbered_adapter(adap);
849 if (r)
850 goto err_unuse_clocks;
851
852 return 0;
853
854err_unuse_clocks:
855 clk_disable_unprepare(dev->clk);
856 dev->clk = NULL;
857 return r;
858}
859
860static int davinci_i2c_remove(struct platform_device *pdev)
861{
862 struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
863
864 i2c_davinci_cpufreq_deregister(dev);
865
866 i2c_del_adapter(&dev->adapter);
867
868 clk_disable_unprepare(dev->clk);
869 dev->clk = NULL;
870
871 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
872
873 return 0;
874}
875
876#ifdef CONFIG_PM
877static int davinci_i2c_suspend(struct device *dev)
878{
879 struct platform_device *pdev = to_platform_device(dev);
880 struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
881
882 /* put I2C into reset */
883 davinci_i2c_reset_ctrl(i2c_dev, 0);
884 clk_disable_unprepare(i2c_dev->clk);
885
886 return 0;
887}
888
889static int davinci_i2c_resume(struct device *dev)
890{
891 struct platform_device *pdev = to_platform_device(dev);
892 struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
893
894 clk_prepare_enable(i2c_dev->clk);
895 /* take I2C out of reset */
896 davinci_i2c_reset_ctrl(i2c_dev, 1);
897
898 return 0;
899}
900
901static const struct dev_pm_ops davinci_i2c_pm = {
902 .suspend = davinci_i2c_suspend,
903 .resume = davinci_i2c_resume,
904};
905
906#define davinci_i2c_pm_ops (&davinci_i2c_pm)
907#else
908#define davinci_i2c_pm_ops NULL
909#endif
910
911/* work with hotplug and coldplug */
912MODULE_ALIAS("platform:i2c_davinci");
913
914static struct platform_driver davinci_i2c_driver = {
915 .probe = davinci_i2c_probe,
916 .remove = davinci_i2c_remove,
917 .driver = {
918 .name = "i2c_davinci",
919 .pm = davinci_i2c_pm_ops,
920 .of_match_table = davinci_i2c_of_match,
921 },
922};
923
924/* I2C may be needed to bring up other drivers */
925static int __init davinci_i2c_init_driver(void)
926{
927 return platform_driver_register(&davinci_i2c_driver);
928}
929subsys_initcall(davinci_i2c_init_driver);
930
931static void __exit davinci_i2c_exit_driver(void)
932{
933 platform_driver_unregister(&davinci_i2c_driver);
934}
935module_exit(davinci_i2c_exit_driver);
936
937MODULE_AUTHOR("Texas Instruments India");
938MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
939MODULE_LICENSE("GPL");