blob: a4f8d33fa389ac95eb2e79e7969428565d150e31 [file] [log] [blame]
srinidhi kasagar3f9900f2010-02-01 19:44:54 +05301/*
2 * Copyright (C) 2009 ST-Ericsson
3 * Copyright (C) 2009 STMicroelectronics
4 *
5 * I2C master mode controller driver, used in Nomadik 8815
6 * and Ux500 platforms.
7 *
8 * Author: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
9 * Author: Sachin Verma <sachin.verma@st.com>
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 version 2, as
13 * published by the Free Software Foundation.
14 */
15#include <linux/init.h>
16#include <linux/module.h>
17#include <linux/platform_device.h>
18#include <linux/delay.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090019#include <linux/slab.h>
srinidhi kasagar3f9900f2010-02-01 19:44:54 +053020#include <linux/interrupt.h>
21#include <linux/i2c.h>
22#include <linux/err.h>
23#include <linux/clk.h>
24#include <linux/io.h>
25
26#include <plat/i2c.h>
27
28#define DRIVER_NAME "nmk-i2c"
29
30/* I2C Controller register offsets */
31#define I2C_CR (0x000)
32#define I2C_SCR (0x004)
33#define I2C_HSMCR (0x008)
34#define I2C_MCR (0x00C)
35#define I2C_TFR (0x010)
36#define I2C_SR (0x014)
37#define I2C_RFR (0x018)
38#define I2C_TFTR (0x01C)
39#define I2C_RFTR (0x020)
40#define I2C_DMAR (0x024)
41#define I2C_BRCR (0x028)
42#define I2C_IMSCR (0x02C)
43#define I2C_RISR (0x030)
44#define I2C_MISR (0x034)
45#define I2C_ICR (0x038)
46
47/* Control registers */
48#define I2C_CR_PE (0x1 << 0) /* Peripheral Enable */
49#define I2C_CR_OM (0x3 << 1) /* Operating mode */
50#define I2C_CR_SAM (0x1 << 3) /* Slave addressing mode */
51#define I2C_CR_SM (0x3 << 4) /* Speed mode */
52#define I2C_CR_SGCM (0x1 << 6) /* Slave general call mode */
53#define I2C_CR_FTX (0x1 << 7) /* Flush Transmit */
54#define I2C_CR_FRX (0x1 << 8) /* Flush Receive */
55#define I2C_CR_DMA_TX_EN (0x1 << 9) /* DMA Tx enable */
56#define I2C_CR_DMA_RX_EN (0x1 << 10) /* DMA Rx Enable */
57#define I2C_CR_DMA_SLE (0x1 << 11) /* DMA sync. logic enable */
58#define I2C_CR_LM (0x1 << 12) /* Loopback mode */
59#define I2C_CR_FON (0x3 << 13) /* Filtering on */
60#define I2C_CR_FS (0x3 << 15) /* Force stop enable */
61
62/* Master controller (MCR) register */
63#define I2C_MCR_OP (0x1 << 0) /* Operation */
64#define I2C_MCR_A7 (0x7f << 1) /* 7-bit address */
65#define I2C_MCR_EA10 (0x7 << 8) /* 10-bit Extended address */
66#define I2C_MCR_SB (0x1 << 11) /* Extended address */
67#define I2C_MCR_AM (0x3 << 12) /* Address type */
68#define I2C_MCR_STOP (0x1 << 14) /* Stop condition */
69#define I2C_MCR_LENGTH (0x7ff << 15) /* Transaction length */
70
71/* Status register (SR) */
72#define I2C_SR_OP (0x3 << 0) /* Operation */
73#define I2C_SR_STATUS (0x3 << 2) /* controller status */
74#define I2C_SR_CAUSE (0x7 << 4) /* Abort cause */
75#define I2C_SR_TYPE (0x3 << 7) /* Receive type */
76#define I2C_SR_LENGTH (0x7ff << 9) /* Transfer length */
77
78/* Interrupt mask set/clear (IMSCR) bits */
79#define I2C_IT_TXFE (0x1 << 0)
80#define I2C_IT_TXFNE (0x1 << 1)
81#define I2C_IT_TXFF (0x1 << 2)
82#define I2C_IT_TXFOVR (0x1 << 3)
83#define I2C_IT_RXFE (0x1 << 4)
84#define I2C_IT_RXFNF (0x1 << 5)
85#define I2C_IT_RXFF (0x1 << 6)
86#define I2C_IT_RFSR (0x1 << 16)
87#define I2C_IT_RFSE (0x1 << 17)
88#define I2C_IT_WTSR (0x1 << 18)
89#define I2C_IT_MTD (0x1 << 19)
90#define I2C_IT_STD (0x1 << 20)
91#define I2C_IT_MAL (0x1 << 24)
92#define I2C_IT_BERR (0x1 << 25)
93#define I2C_IT_MTDWS (0x1 << 28)
94
95#define GEN_MASK(val, mask, sb) (((val) << (sb)) & (mask))
96
97/* some bits in ICR are reserved */
98#define I2C_CLEAR_ALL_INTS 0x131f007f
99
100/* first three msb bits are reserved */
101#define IRQ_MASK(mask) (mask & 0x1fffffff)
102
103/* maximum threshold value */
104#define MAX_I2C_FIFO_THRESHOLD 15
105
106enum i2c_status {
107 I2C_NOP,
108 I2C_ON_GOING,
109 I2C_OK,
110 I2C_ABORT
111};
112
113/* operation */
114enum i2c_operation {
115 I2C_NO_OPERATION = 0xff,
116 I2C_WRITE = 0x00,
117 I2C_READ = 0x01
118};
119
120/* controller response timeout in ms */
121#define I2C_TIMEOUT_MS 500
122
123/**
124 * struct i2c_nmk_client - client specific data
125 * @slave_adr: 7-bit slave address
126 * @count: no. bytes to be transfered
127 * @buffer: client data buffer
128 * @xfer_bytes: bytes transfered till now
129 * @operation: current I2C operation
130 */
131struct i2c_nmk_client {
132 unsigned short slave_adr;
133 unsigned long count;
134 unsigned char *buffer;
135 unsigned long xfer_bytes;
136 enum i2c_operation operation;
137};
138
139/**
140 * struct nmk_i2c_dev - private data structure of the controller
141 * @pdev: parent platform device
142 * @adap: corresponding I2C adapter
143 * @irq: interrupt line for the controller
144 * @virtbase: virtual io memory area
145 * @clk: hardware i2c block clock
146 * @cfg: machine provided controller configuration
147 * @cli: holder of client specific data
148 * @stop: stop condition
149 * @xfer_complete: acknowledge completion for a I2C message
150 * @result: controller propogated result
151 */
152struct nmk_i2c_dev {
153 struct platform_device *pdev;
154 struct i2c_adapter adap;
155 int irq;
156 void __iomem *virtbase;
157 struct clk *clk;
158 struct nmk_i2c_controller cfg;
159 struct i2c_nmk_client cli;
160 int stop;
161 struct completion xfer_complete;
162 int result;
163};
164
165/* controller's abort causes */
166static const char *abort_causes[] = {
167 "no ack received after address transmission",
168 "no ack received during data phase",
169 "ack received after xmission of master code",
170 "master lost arbitration",
171 "slave restarts",
172 "slave reset",
173 "overflow, maxsize is 2047 bytes",
174};
175
176static inline void i2c_set_bit(void __iomem *reg, u32 mask)
177{
178 writel(readl(reg) | mask, reg);
179}
180
181static inline void i2c_clr_bit(void __iomem *reg, u32 mask)
182{
183 writel(readl(reg) & ~mask, reg);
184}
185
186/**
187 * flush_i2c_fifo() - This function flushes the I2C FIFO
188 * @dev: private data of I2C Driver
189 *
190 * This function flushes the I2C Tx and Rx FIFOs. It returns
191 * 0 on successful flushing of FIFO
192 */
193static int flush_i2c_fifo(struct nmk_i2c_dev *dev)
194{
195#define LOOP_ATTEMPTS 10
196 int i;
197 unsigned long timeout;
198
199 /*
200 * flush the transmit and receive FIFO. The flushing
201 * operation takes several cycles before to be completed.
202 * On the completion, the I2C internal logic clears these
203 * bits, until then no one must access Tx, Rx FIFO and
204 * should poll on these bits waiting for the completion.
205 */
206 writel((I2C_CR_FTX | I2C_CR_FRX), dev->virtbase + I2C_CR);
207
208 for (i = 0; i < LOOP_ATTEMPTS; i++) {
209 timeout = jiffies + msecs_to_jiffies(I2C_TIMEOUT_MS);
210
211 while (!time_after(jiffies, timeout)) {
212 if ((readl(dev->virtbase + I2C_CR) &
213 (I2C_CR_FTX | I2C_CR_FRX)) == 0)
214 return 0;
215 }
216 }
217
218 dev_err(&dev->pdev->dev, "flushing operation timed out "
219 "giving up after %d attempts", LOOP_ATTEMPTS);
220
221 return -ETIMEDOUT;
222}
223
224/**
225 * disable_all_interrupts() - Disable all interrupts of this I2c Bus
226 * @dev: private data of I2C Driver
227 */
228static void disable_all_interrupts(struct nmk_i2c_dev *dev)
229{
230 u32 mask = IRQ_MASK(0);
231 writel(mask, dev->virtbase + I2C_IMSCR);
232}
233
234/**
235 * clear_all_interrupts() - Clear all interrupts of I2C Controller
236 * @dev: private data of I2C Driver
237 */
238static void clear_all_interrupts(struct nmk_i2c_dev *dev)
239{
240 u32 mask;
241 mask = IRQ_MASK(I2C_CLEAR_ALL_INTS);
242 writel(mask, dev->virtbase + I2C_ICR);
243}
244
245/**
246 * init_hw() - initialize the I2C hardware
247 * @dev: private data of I2C Driver
248 */
249static int init_hw(struct nmk_i2c_dev *dev)
250{
251 int stat;
252
253 stat = flush_i2c_fifo(dev);
254 if (stat)
255 return stat;
256
257 /* disable the controller */
258 i2c_clr_bit(dev->virtbase + I2C_CR , I2C_CR_PE);
259
260 disable_all_interrupts(dev);
261
262 clear_all_interrupts(dev);
263
264 dev->cli.operation = I2C_NO_OPERATION;
265
266 return 0;
267}
268
269/* enable peripheral, master mode operation */
270#define DEFAULT_I2C_REG_CR ((1 << 1) | I2C_CR_PE)
271
272/**
273 * load_i2c_mcr_reg() - load the MCR register
274 * @dev: private data of controller
275 */
276static u32 load_i2c_mcr_reg(struct nmk_i2c_dev *dev)
277{
278 u32 mcr = 0;
279
280 /* 7-bit address transaction */
281 mcr |= GEN_MASK(1, I2C_MCR_AM, 12);
282 mcr |= GEN_MASK(dev->cli.slave_adr, I2C_MCR_A7, 1);
283
284 /* start byte procedure not applied */
285 mcr |= GEN_MASK(0, I2C_MCR_SB, 11);
286
287 /* check the operation, master read/write? */
288 if (dev->cli.operation == I2C_WRITE)
289 mcr |= GEN_MASK(I2C_WRITE, I2C_MCR_OP, 0);
290 else
291 mcr |= GEN_MASK(I2C_READ, I2C_MCR_OP, 0);
292
293 /* stop or repeated start? */
294 if (dev->stop)
295 mcr |= GEN_MASK(1, I2C_MCR_STOP, 14);
296 else
297 mcr &= ~(GEN_MASK(1, I2C_MCR_STOP, 14));
298
299 mcr |= GEN_MASK(dev->cli.count, I2C_MCR_LENGTH, 15);
300
301 return mcr;
302}
303
304/**
305 * setup_i2c_controller() - setup the controller
306 * @dev: private data of controller
307 */
308static void setup_i2c_controller(struct nmk_i2c_dev *dev)
309{
310 u32 brcr1, brcr2;
311 u32 i2c_clk, div;
312
313 writel(0x0, dev->virtbase + I2C_CR);
314 writel(0x0, dev->virtbase + I2C_HSMCR);
315 writel(0x0, dev->virtbase + I2C_TFTR);
316 writel(0x0, dev->virtbase + I2C_RFTR);
317 writel(0x0, dev->virtbase + I2C_DMAR);
318
319 /*
320 * set the slsu:
321 *
322 * slsu defines the data setup time after SCL clock
323 * stretching in terms of i2c clk cycles. The
324 * needed setup time for the three modes are 250ns,
325 * 100ns, 10ns repectively thus leading to the values
326 * of 14, 6, 2 for a 48 MHz i2c clk.
327 */
328 writel(dev->cfg.slsu << 16, dev->virtbase + I2C_SCR);
329
330 i2c_clk = clk_get_rate(dev->clk);
331
332 /* fallback to std. mode if machine has not provided it */
333 if (dev->cfg.clk_freq == 0)
334 dev->cfg.clk_freq = 100000;
335
336 /*
337 * The spec says, in case of std. mode the divider is
338 * 2 whereas it is 3 for fast and fastplus mode of
339 * operation. TODO - high speed support.
340 */
341 div = (dev->cfg.clk_freq > 100000) ? 3 : 2;
342
343 /*
344 * generate the mask for baud rate counters. The controller
345 * has two baud rate counters. One is used for High speed
346 * operation, and the other is for std, fast mode, fast mode
347 * plus operation. Currently we do not supprt high speed mode
348 * so set brcr1 to 0.
349 */
350 brcr1 = 0 << 16;
351 brcr2 = (i2c_clk/(dev->cfg.clk_freq * div)) & 0xffff;
352
353 /* set the baud rate counter register */
354 writel((brcr1 | brcr2), dev->virtbase + I2C_BRCR);
355
356 /*
357 * set the speed mode. Currently we support
358 * only standard and fast mode of operation
359 * TODO - support for fast mode plus (upto 1Mb/s)
360 * and high speed (up to 3.4 Mb/s)
361 */
362 if (dev->cfg.sm > I2C_FREQ_MODE_FAST) {
363 dev_err(&dev->pdev->dev, "do not support this mode "
364 "defaulting to std. mode\n");
365 brcr2 = i2c_clk/(100000 * 2) & 0xffff;
366 writel((brcr1 | brcr2), dev->virtbase + I2C_BRCR);
367 writel(I2C_FREQ_MODE_STANDARD << 4,
368 dev->virtbase + I2C_CR);
369 }
370 writel(dev->cfg.sm << 4, dev->virtbase + I2C_CR);
371
372 /* set the Tx and Rx FIFO threshold */
373 writel(dev->cfg.tft, dev->virtbase + I2C_TFTR);
374 writel(dev->cfg.rft, dev->virtbase + I2C_RFTR);
375}
376
377/**
378 * read_i2c() - Read from I2C client device
379 * @dev: private data of I2C Driver
380 *
381 * This function reads from i2c client device when controller is in
382 * master mode. There is a completion timeout. If there is no transfer
383 * before timeout error is returned.
384 */
385static int read_i2c(struct nmk_i2c_dev *dev)
386{
387 u32 status = 0;
388 u32 mcr;
389 u32 irq_mask = 0;
390 int timeout;
391
392 mcr = load_i2c_mcr_reg(dev);
393 writel(mcr, dev->virtbase + I2C_MCR);
394
395 /* load the current CR value */
396 writel(readl(dev->virtbase + I2C_CR) | DEFAULT_I2C_REG_CR,
397 dev->virtbase + I2C_CR);
398
399 /* enable the controller */
400 i2c_set_bit(dev->virtbase + I2C_CR, I2C_CR_PE);
401
402 init_completion(&dev->xfer_complete);
403
404 /* enable interrupts by setting the mask */
405 irq_mask = (I2C_IT_RXFNF | I2C_IT_RXFF |
406 I2C_IT_MAL | I2C_IT_BERR);
407
408 if (dev->stop)
409 irq_mask |= I2C_IT_MTD;
410 else
411 irq_mask |= I2C_IT_MTDWS;
412
413 irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask);
414
415 writel(readl(dev->virtbase + I2C_IMSCR) | irq_mask,
416 dev->virtbase + I2C_IMSCR);
417
418 timeout = wait_for_completion_interruptible_timeout(
419 &dev->xfer_complete, msecs_to_jiffies(I2C_TIMEOUT_MS));
420
421 if (timeout < 0) {
422 dev_err(&dev->pdev->dev,
423 "wait_for_completion_interruptible_timeout"
424 "returned %d waiting for event\n", timeout);
425 status = timeout;
426 }
427
428 if (timeout == 0) {
429 /* controler has timedout, re-init the h/w */
430 dev_err(&dev->pdev->dev, "controller timed out, re-init h/w\n");
431 (void) init_hw(dev);
432 status = -ETIMEDOUT;
433 }
434
435 return status;
436}
437
438/**
439 * write_i2c() - Write data to I2C client.
440 * @dev: private data of I2C Driver
441 *
442 * This function writes data to I2C client
443 */
444static int write_i2c(struct nmk_i2c_dev *dev)
445{
446 u32 status = 0;
447 u32 mcr;
448 u32 irq_mask = 0;
449 int timeout;
450
451 mcr = load_i2c_mcr_reg(dev);
452
453 writel(mcr, dev->virtbase + I2C_MCR);
454
455 /* load the current CR value */
456 writel(readl(dev->virtbase + I2C_CR) | DEFAULT_I2C_REG_CR,
457 dev->virtbase + I2C_CR);
458
459 /* enable the controller */
460 i2c_set_bit(dev->virtbase + I2C_CR , I2C_CR_PE);
461
462 init_completion(&dev->xfer_complete);
463
464 /* enable interrupts by settings the masks */
465 irq_mask = (I2C_IT_TXFNE | I2C_IT_TXFOVR |
466 I2C_IT_MAL | I2C_IT_BERR);
467
468 /*
469 * check if we want to transfer a single or multiple bytes, if so
470 * set the MTDWS bit (Master Transaction Done Without Stop)
471 * to start repeated start operation
472 */
473 if (dev->stop)
474 irq_mask |= I2C_IT_MTD;
475 else
476 irq_mask |= I2C_IT_MTDWS;
477
478 irq_mask = I2C_CLEAR_ALL_INTS & IRQ_MASK(irq_mask);
479
480 writel(readl(dev->virtbase + I2C_IMSCR) | irq_mask,
481 dev->virtbase + I2C_IMSCR);
482
483 timeout = wait_for_completion_interruptible_timeout(
484 &dev->xfer_complete, msecs_to_jiffies(I2C_TIMEOUT_MS));
485
486 if (timeout < 0) {
487 dev_err(&dev->pdev->dev,
488 "wait_for_completion_interruptible_timeout"
489 "returned %d waiting for event\n", timeout);
490 status = timeout;
491 }
492
493 if (timeout == 0) {
494 /* controler has timedout, re-init the h/w */
495 dev_err(&dev->pdev->dev, "controller timed out, re-init h/w\n");
496 (void) init_hw(dev);
497 status = -ETIMEDOUT;
498 }
499
500 return status;
501}
502
503/**
504 * nmk_i2c_xfer() - I2C transfer function used by kernel framework
505 * @i2c_adap - Adapter pointer to the controller
506 * @msgs[] - Pointer to data to be written.
507 * @num_msgs - Number of messages to be executed
508 *
509 * This is the function called by the generic kernel i2c_transfer()
510 * or i2c_smbus...() API calls. Note that this code is protected by the
511 * semaphore set in the kernel i2c_transfer() function.
512 *
513 * NOTE:
514 * READ TRANSFER : We impose a restriction of the first message to be the
515 * index message for any read transaction.
516 * - a no index is coded as '0',
517 * - 2byte big endian index is coded as '3'
518 * !!! msg[0].buf holds the actual index.
519 * This is compatible with generic messages of smbus emulator
520 * that send a one byte index.
521 * eg. a I2C transation to read 2 bytes from index 0
522 * idx = 0;
523 * msg[0].addr = client->addr;
524 * msg[0].flags = 0x0;
525 * msg[0].len = 1;
526 * msg[0].buf = &idx;
527 *
528 * msg[1].addr = client->addr;
529 * msg[1].flags = I2C_M_RD;
530 * msg[1].len = 2;
531 * msg[1].buf = rd_buff
532 * i2c_transfer(adap, msg, 2);
533 *
534 * WRITE TRANSFER : The I2C standard interface interprets all data as payload.
535 * If you want to emulate an SMBUS write transaction put the
536 * index as first byte(or first and second) in the payload.
537 * eg. a I2C transation to write 2 bytes from index 1
538 * wr_buff[0] = 0x1;
539 * wr_buff[1] = 0x23;
540 * wr_buff[2] = 0x46;
541 * msg[0].flags = 0x0;
542 * msg[0].len = 3;
543 * msg[0].buf = wr_buff;
544 * i2c_transfer(adap, msg, 1);
545 *
546 * To read or write a block of data (multiple bytes) using SMBUS emulation
547 * please use the i2c_smbus_read_i2c_block_data()
548 * or i2c_smbus_write_i2c_block_data() API
549 */
550static int nmk_i2c_xfer(struct i2c_adapter *i2c_adap,
551 struct i2c_msg msgs[], int num_msgs)
552{
553 int status;
554 int i;
555 u32 cause;
556 struct nmk_i2c_dev *dev = i2c_get_adapdata(i2c_adap);
557
558 status = init_hw(dev);
559 if (status)
560 return status;
561
562 /* setup the i2c controller */
563 setup_i2c_controller(dev);
564
565 for (i = 0; i < num_msgs; i++) {
566 if (unlikely(msgs[i].flags & I2C_M_TEN)) {
567 dev_err(&dev->pdev->dev, "10 bit addressing"
568 "not supported\n");
569 return -EINVAL;
570 }
571 dev->cli.slave_adr = msgs[i].addr;
572 dev->cli.buffer = msgs[i].buf;
573 dev->cli.count = msgs[i].len;
574 dev->stop = (i < (num_msgs - 1)) ? 0 : 1;
575 dev->result = 0;
576
577 if (msgs[i].flags & I2C_M_RD) {
578 /* it is a read operation */
579 dev->cli.operation = I2C_READ;
580 status = read_i2c(dev);
581 } else {
582 /* write operation */
583 dev->cli.operation = I2C_WRITE;
584 status = write_i2c(dev);
585 }
586 if (status || (dev->result)) {
587 /* get the abort cause */
588 cause = (readl(dev->virtbase + I2C_SR) >> 4) & 0x7;
589 dev_err(&dev->pdev->dev, "error during I2C"
590 "message xfer: %d\n", cause);
591 dev_err(&dev->pdev->dev, "%s\n",
592 cause >= ARRAY_SIZE(abort_causes)
593 ? "unknown reason" : abort_causes[cause]);
594 return status;
595 }
596 mdelay(1);
597 }
598 /* return the no. messages processed */
599 if (status)
600 return status;
601 else
602 return num_msgs;
603}
604
605/**
606 * disable_interrupts() - disable the interrupts
607 * @dev: private data of controller
608 */
609static int disable_interrupts(struct nmk_i2c_dev *dev, u32 irq)
610{
611 irq = IRQ_MASK(irq);
612 writel(readl(dev->virtbase + I2C_IMSCR) & ~(I2C_CLEAR_ALL_INTS & irq),
613 dev->virtbase + I2C_IMSCR);
614 return 0;
615}
616
617/**
618 * i2c_irq_handler() - interrupt routine
619 * @irq: interrupt number
620 * @arg: data passed to the handler
621 *
622 * This is the interrupt handler for the i2c driver. Currently
623 * it handles the major interrupts like Rx & Tx FIFO management
624 * interrupts, master transaction interrupts, arbitration and
625 * bus error interrupts. The rest of the interrupts are treated as
626 * unhandled.
627 */
628static irqreturn_t i2c_irq_handler(int irq, void *arg)
629{
630 struct nmk_i2c_dev *dev = arg;
631 u32 tft, rft;
632 u32 count;
633 u32 misr;
634 u32 src = 0;
635
636 /* load Tx FIFO and Rx FIFO threshold values */
637 tft = readl(dev->virtbase + I2C_TFTR);
638 rft = readl(dev->virtbase + I2C_RFTR);
639
640 /* read interrupt status register */
641 misr = readl(dev->virtbase + I2C_MISR);
642
643 src = __ffs(misr);
644 switch ((1 << src)) {
645
646 /* Transmit FIFO nearly empty interrupt */
647 case I2C_IT_TXFNE:
648 {
649 if (dev->cli.operation == I2C_READ) {
650 /*
651 * in read operation why do we care for writing?
652 * so disable the Transmit FIFO interrupt
653 */
654 disable_interrupts(dev, I2C_IT_TXFNE);
655 } else {
656 for (count = (MAX_I2C_FIFO_THRESHOLD - tft - 2);
657 (count > 0) &&
658 (dev->cli.count != 0);
659 count--) {
660 /* write to the Tx FIFO */
661 writeb(*dev->cli.buffer,
662 dev->virtbase + I2C_TFR);
663 dev->cli.buffer++;
664 dev->cli.count--;
665 dev->cli.xfer_bytes++;
666 }
667 /*
668 * if done, close the transfer by disabling the
669 * corresponding TXFNE interrupt
670 */
671 if (dev->cli.count == 0)
672 disable_interrupts(dev, I2C_IT_TXFNE);
673 }
674 }
675 break;
676
677 /*
678 * Rx FIFO nearly full interrupt.
679 * This is set when the numer of entries in Rx FIFO is
680 * greater or equal than the threshold value programmed
681 * in RFT
682 */
683 case I2C_IT_RXFNF:
684 for (count = rft; count > 0; count--) {
685 /* Read the Rx FIFO */
686 *dev->cli.buffer = readb(dev->virtbase + I2C_RFR);
687 dev->cli.buffer++;
688 }
689 dev->cli.count -= rft;
690 dev->cli.xfer_bytes += rft;
691 break;
692
693 /* Rx FIFO full */
694 case I2C_IT_RXFF:
695 for (count = MAX_I2C_FIFO_THRESHOLD; count > 0; count--) {
696 *dev->cli.buffer = readb(dev->virtbase + I2C_RFR);
697 dev->cli.buffer++;
698 }
699 dev->cli.count -= MAX_I2C_FIFO_THRESHOLD;
700 dev->cli.xfer_bytes += MAX_I2C_FIFO_THRESHOLD;
701 break;
702
703 /* Master Transaction Done with/without stop */
704 case I2C_IT_MTD:
705 case I2C_IT_MTDWS:
706 if (dev->cli.operation == I2C_READ) {
707 while (!readl(dev->virtbase + I2C_RISR) & I2C_IT_RXFE) {
708 if (dev->cli.count == 0)
709 break;
710 *dev->cli.buffer =
711 readb(dev->virtbase + I2C_RFR);
712 dev->cli.buffer++;
713 dev->cli.count--;
714 dev->cli.xfer_bytes++;
715 }
716 }
717
718 i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_MTD);
719 i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_MTDWS);
720
721 disable_interrupts(dev,
722 (I2C_IT_TXFNE | I2C_IT_TXFE | I2C_IT_TXFF
723 | I2C_IT_TXFOVR | I2C_IT_RXFNF
724 | I2C_IT_RXFF | I2C_IT_RXFE));
725
726 if (dev->cli.count) {
727 dev->result = -1;
728 dev_err(&dev->pdev->dev, "%lu bytes still remain to be"
729 "xfered\n", dev->cli.count);
730 (void) init_hw(dev);
731 }
732 complete(&dev->xfer_complete);
733
734 break;
735
736 /* Master Arbitration lost interrupt */
737 case I2C_IT_MAL:
738 dev->result = -1;
739 (void) init_hw(dev);
740
741 i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_MAL);
742 complete(&dev->xfer_complete);
743
744 break;
745
746 /*
747 * Bus Error interrupt.
748 * This happens when an unexpected start/stop condition occurs
749 * during the transaction.
750 */
751 case I2C_IT_BERR:
752 dev->result = -1;
753 /* get the status */
754 if (((readl(dev->virtbase + I2C_SR) >> 2) & 0x3) == I2C_ABORT)
755 (void) init_hw(dev);
756
757 i2c_set_bit(dev->virtbase + I2C_ICR, I2C_IT_BERR);
758 complete(&dev->xfer_complete);
759
760 break;
761
762 /*
763 * Tx FIFO overrun interrupt.
764 * This is set when a write operation in Tx FIFO is performed and
765 * the Tx FIFO is full.
766 */
767 case I2C_IT_TXFOVR:
768 dev->result = -1;
769 (void) init_hw(dev);
770
771 dev_err(&dev->pdev->dev, "Tx Fifo Over run\n");
772 complete(&dev->xfer_complete);
773
774 break;
775
776 /* unhandled interrupts by this driver - TODO*/
777 case I2C_IT_TXFE:
778 case I2C_IT_TXFF:
779 case I2C_IT_RXFE:
780 case I2C_IT_RFSR:
781 case I2C_IT_RFSE:
782 case I2C_IT_WTSR:
783 case I2C_IT_STD:
784 dev_err(&dev->pdev->dev, "unhandled Interrupt\n");
785 break;
786 default:
787 dev_err(&dev->pdev->dev, "spurious Interrupt..\n");
788 break;
789 }
790
791 return IRQ_HANDLED;
792}
793
794static unsigned int nmk_i2c_functionality(struct i2c_adapter *adap)
795{
796 return I2C_FUNC_I2C
797 | I2C_FUNC_SMBUS_BYTE_DATA
798 | I2C_FUNC_SMBUS_WORD_DATA
799 | I2C_FUNC_SMBUS_I2C_BLOCK;
800}
801
802static const struct i2c_algorithm nmk_i2c_algo = {
803 .master_xfer = nmk_i2c_xfer,
804 .functionality = nmk_i2c_functionality
805};
806
807static int __devinit nmk_i2c_probe(struct platform_device *pdev)
808{
809 int ret = 0;
810 struct resource *res;
811 struct nmk_i2c_controller *pdata =
812 pdev->dev.platform_data;
813 struct nmk_i2c_dev *dev;
814 struct i2c_adapter *adap;
815
816 dev = kzalloc(sizeof(struct nmk_i2c_dev), GFP_KERNEL);
817 if (!dev) {
818 dev_err(&pdev->dev, "cannot allocate memory\n");
819 ret = -ENOMEM;
820 goto err_no_mem;
821 }
822
823 dev->pdev = pdev;
824 platform_set_drvdata(pdev, dev);
825
826 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
827 if (!res) {
828 ret = -ENOENT;
829 goto err_no_resource;
830 }
831
832 if (request_mem_region(res->start, resource_size(res),
833 DRIVER_NAME "I/O region") == NULL) {
834 ret = -EBUSY;
835 goto err_no_region;
836 }
837
838 dev->virtbase = ioremap(res->start, resource_size(res));
839 if (!dev->virtbase) {
840 ret = -ENOMEM;
841 goto err_no_ioremap;
842 }
843
844 dev->irq = platform_get_irq(pdev, 0);
845 ret = request_irq(dev->irq, i2c_irq_handler, IRQF_DISABLED,
846 DRIVER_NAME, dev);
847 if (ret) {
848 dev_err(&pdev->dev, "cannot claim the irq %d\n", dev->irq);
849 goto err_irq;
850 }
851
852 dev->clk = clk_get(&pdev->dev, NULL);
853 if (IS_ERR(dev->clk)) {
854 dev_err(&pdev->dev, "could not get i2c clock\n");
855 ret = PTR_ERR(dev->clk);
856 goto err_no_clk;
857 }
858
859 clk_enable(dev->clk);
860
861 adap = &dev->adap;
862 adap->dev.parent = &pdev->dev;
863 adap->owner = THIS_MODULE;
864 adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
865 adap->algo = &nmk_i2c_algo;
866
867 /* fetch the controller id */
868 adap->nr = pdev->id;
869
870 /* fetch the controller configuration from machine */
871 dev->cfg.clk_freq = pdata->clk_freq;
872 dev->cfg.slsu = pdata->slsu;
873 dev->cfg.tft = pdata->tft;
874 dev->cfg.rft = pdata->rft;
875 dev->cfg.sm = pdata->sm;
876
877 i2c_set_adapdata(adap, dev);
878
879 ret = init_hw(dev);
880 if (ret != 0) {
881 dev_err(&pdev->dev, "error in initializing i2c hardware\n");
882 goto err_init_hw;
883 }
884
885 dev_dbg(&pdev->dev, "initialize I2C%d bus on virtual "
886 "base %p\n", pdev->id, dev->virtbase);
887
888 ret = i2c_add_numbered_adapter(adap);
889 if (ret) {
890 dev_err(&pdev->dev, "failed to add adapter\n");
891 goto err_add_adap;
892 }
893
894 return 0;
895
896 err_init_hw:
897 clk_disable(dev->clk);
898 err_add_adap:
899 clk_put(dev->clk);
900 err_no_clk:
901 free_irq(dev->irq, dev);
902 err_irq:
903 iounmap(dev->virtbase);
904 err_no_ioremap:
905 release_mem_region(res->start, resource_size(res));
906 err_no_region:
907 platform_set_drvdata(pdev, NULL);
908 err_no_resource:
909 kfree(dev);
910 err_no_mem:
911
912 return ret;
913}
914
915static int __devexit nmk_i2c_remove(struct platform_device *pdev)
916{
917 struct nmk_i2c_dev *dev = platform_get_drvdata(pdev);
918
919 i2c_del_adapter(&dev->adap);
920 flush_i2c_fifo(dev);
921 disable_all_interrupts(dev);
922 clear_all_interrupts(dev);
923 /* disable the controller */
924 i2c_clr_bit(dev->virtbase + I2C_CR, I2C_CR_PE);
925 free_irq(dev->irq, dev);
926 iounmap(dev->virtbase);
927 clk_disable(dev->clk);
928 clk_put(dev->clk);
929 platform_set_drvdata(pdev, NULL);
930 kfree(dev);
931
932 return 0;
933}
934
935static struct platform_driver nmk_i2c_driver = {
936 .driver = {
937 .owner = THIS_MODULE,
938 .name = DRIVER_NAME,
939 },
940 .probe = nmk_i2c_probe,
941 .remove = __devexit_p(nmk_i2c_remove),
942};
943
944static int __init nmk_i2c_init(void)
945{
946 return platform_driver_register(&nmk_i2c_driver);
947}
948
949static void __exit nmk_i2c_exit(void)
950{
951 platform_driver_unregister(&nmk_i2c_driver);
952}
953
954subsys_initcall(nmk_i2c_init);
955module_exit(nmk_i2c_exit);
956
957MODULE_AUTHOR("Sachin Verma, Srinidhi KASAGAR");
958MODULE_DESCRIPTION("Nomadik/Ux500 I2C driver");
959MODULE_LICENSE("GPL");
960MODULE_ALIAS("platform:" DRIVER_NAME);