Linux 2.6.33-rc8
[linux-2.6/lguest.git] / drivers / i2c / busses / i2c-davinci.c
blobc89687a10835538307212949317042f40042129c
1 /*
2 * TI DAVINCI I2C adapter driver.
4 * Copyright (C) 2006 Texas Instruments.
5 * Copyright (C) 2007 MontaVista Software Inc.
7 * Updated by Vinod & Sudhakar Feb 2005
9 * ----------------------------------------------------------------------------
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.
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.
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 * ----------------------------------------------------------------------------
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>
39 #include <mach/hardware.h>
41 #include <mach/i2c.h>
43 /* ----- global defines ----------------------------------------------- */
45 #define DAVINCI_I2C_TIMEOUT (1*HZ)
46 #define I2C_DAVINCI_INTR_ALL (DAVINCI_I2C_IMR_AAS | \
47 DAVINCI_I2C_IMR_SCD | \
48 DAVINCI_I2C_IMR_ARDY | \
49 DAVINCI_I2C_IMR_NACK | \
50 DAVINCI_I2C_IMR_AL)
52 #define DAVINCI_I2C_OAR_REG 0x00
53 #define DAVINCI_I2C_IMR_REG 0x04
54 #define DAVINCI_I2C_STR_REG 0x08
55 #define DAVINCI_I2C_CLKL_REG 0x0c
56 #define DAVINCI_I2C_CLKH_REG 0x10
57 #define DAVINCI_I2C_CNT_REG 0x14
58 #define DAVINCI_I2C_DRR_REG 0x18
59 #define DAVINCI_I2C_SAR_REG 0x1c
60 #define DAVINCI_I2C_DXR_REG 0x20
61 #define DAVINCI_I2C_MDR_REG 0x24
62 #define DAVINCI_I2C_IVR_REG 0x28
63 #define DAVINCI_I2C_EMDR_REG 0x2c
64 #define DAVINCI_I2C_PSC_REG 0x30
66 #define DAVINCI_I2C_IVR_AAS 0x07
67 #define DAVINCI_I2C_IVR_SCD 0x06
68 #define DAVINCI_I2C_IVR_XRDY 0x05
69 #define DAVINCI_I2C_IVR_RDR 0x04
70 #define DAVINCI_I2C_IVR_ARDY 0x03
71 #define DAVINCI_I2C_IVR_NACK 0x02
72 #define DAVINCI_I2C_IVR_AL 0x01
74 #define DAVINCI_I2C_STR_BB (1 << 12)
75 #define DAVINCI_I2C_STR_RSFULL (1 << 11)
76 #define DAVINCI_I2C_STR_SCD (1 << 5)
77 #define DAVINCI_I2C_STR_ARDY (1 << 2)
78 #define DAVINCI_I2C_STR_NACK (1 << 1)
79 #define DAVINCI_I2C_STR_AL (1 << 0)
81 #define DAVINCI_I2C_MDR_NACK (1 << 15)
82 #define DAVINCI_I2C_MDR_STT (1 << 13)
83 #define DAVINCI_I2C_MDR_STP (1 << 11)
84 #define DAVINCI_I2C_MDR_MST (1 << 10)
85 #define DAVINCI_I2C_MDR_TRX (1 << 9)
86 #define DAVINCI_I2C_MDR_XA (1 << 8)
87 #define DAVINCI_I2C_MDR_RM (1 << 7)
88 #define DAVINCI_I2C_MDR_IRS (1 << 5)
90 #define DAVINCI_I2C_IMR_AAS (1 << 6)
91 #define DAVINCI_I2C_IMR_SCD (1 << 5)
92 #define DAVINCI_I2C_IMR_XRDY (1 << 4)
93 #define DAVINCI_I2C_IMR_RRDY (1 << 3)
94 #define DAVINCI_I2C_IMR_ARDY (1 << 2)
95 #define DAVINCI_I2C_IMR_NACK (1 << 1)
96 #define DAVINCI_I2C_IMR_AL (1 << 0)
98 #define MOD_REG_BIT(val, mask, set) do { \
99 if (set) { \
100 val |= mask; \
101 } else { \
102 val &= ~mask; \
104 } while (0)
106 struct davinci_i2c_dev {
107 struct device *dev;
108 void __iomem *base;
109 struct completion cmd_complete;
110 struct clk *clk;
111 int cmd_err;
112 u8 *buf;
113 size_t buf_len;
114 int irq;
115 u8 terminate;
116 struct i2c_adapter adapter;
119 /* default platform data to use if not supplied in the platform_device */
120 static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
121 .bus_freq = 100,
122 .bus_delay = 0,
125 static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
126 int reg, u16 val)
128 __raw_writew(val, i2c_dev->base + reg);
131 static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
133 return __raw_readw(i2c_dev->base + reg);
137 * This functions configures I2C and brings I2C out of reset.
138 * This function is called during I2C init function. This function
139 * also gets called if I2C encounters any errors.
141 static int i2c_davinci_init(struct davinci_i2c_dev *dev)
143 struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
144 u16 psc;
145 u32 clk;
146 u32 d;
147 u32 clkh;
148 u32 clkl;
149 u32 input_clock = clk_get_rate(dev->clk);
150 u16 w;
152 if (!pdata)
153 pdata = &davinci_i2c_platform_data_default;
155 /* put I2C into reset */
156 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
157 MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 0);
158 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
160 /* NOTE: I2C Clock divider programming info
161 * As per I2C specs the following formulas provide prescaler
162 * and low/high divider values
163 * input clk --> PSC Div -----------> ICCL/H Div --> output clock
164 * module clk
166 * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
168 * Thus,
169 * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
171 * where if PSC == 0, d = 7,
172 * if PSC == 1, d = 6
173 * if PSC > 1 , d = 5
176 /* get minimum of 7 MHz clock, but max of 12 MHz */
177 psc = (input_clock / 7000000) - 1;
178 if ((input_clock / (psc + 1)) > 12000000)
179 psc++; /* better to run under spec than over */
180 d = (psc >= 2) ? 5 : 7 - psc;
182 clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1);
183 clkh = clk >> 1;
184 clkl = clk - clkh;
186 davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
187 davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
188 davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
190 /* Respond at reserved "SMBus Host" slave address" (and zero);
191 * we seem to have no option to not respond...
193 davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08);
195 dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
196 dev_dbg(dev->dev, "PSC = %d\n",
197 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
198 dev_dbg(dev->dev, "CLKL = %d\n",
199 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
200 dev_dbg(dev->dev, "CLKH = %d\n",
201 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
202 dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
203 pdata->bus_freq, pdata->bus_delay);
205 /* Take the I2C module out of reset: */
206 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
207 MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 1);
208 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
210 /* Enable interrupts */
211 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
213 return 0;
217 * Waiting for bus not busy
219 static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
220 char allow_sleep)
222 unsigned long timeout;
224 timeout = jiffies + dev->adapter.timeout;
225 while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
226 & DAVINCI_I2C_STR_BB) {
227 if (time_after(jiffies, timeout)) {
228 dev_warn(dev->dev,
229 "timeout waiting for bus ready\n");
230 return -ETIMEDOUT;
232 if (allow_sleep)
233 schedule_timeout(1);
236 return 0;
240 * Low level master read/write transaction. This function is called
241 * from i2c_davinci_xfer.
243 static int
244 i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
246 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
247 struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
248 u32 flag;
249 u16 w;
250 int r;
252 if (msg->len == 0)
253 return -EINVAL;
255 if (!pdata)
256 pdata = &davinci_i2c_platform_data_default;
257 /* Introduce a delay, required for some boards (e.g Davinci EVM) */
258 if (pdata->bus_delay)
259 udelay(pdata->bus_delay);
261 /* set the slave address */
262 davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
264 dev->buf = msg->buf;
265 dev->buf_len = msg->len;
267 davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
269 INIT_COMPLETION(dev->cmd_complete);
270 dev->cmd_err = 0;
272 /* Take I2C out of reset, configure it as master and set the
273 * start bit */
274 flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST | DAVINCI_I2C_MDR_STT;
276 /* if the slave address is ten bit address, enable XA bit */
277 if (msg->flags & I2C_M_TEN)
278 flag |= DAVINCI_I2C_MDR_XA;
279 if (!(msg->flags & I2C_M_RD))
280 flag |= DAVINCI_I2C_MDR_TRX;
281 if (stop)
282 flag |= DAVINCI_I2C_MDR_STP;
284 /* Enable receive or transmit interrupts */
285 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
286 if (msg->flags & I2C_M_RD)
287 MOD_REG_BIT(w, DAVINCI_I2C_IMR_RRDY, 1);
288 else
289 MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 1);
290 davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
292 dev->terminate = 0;
293 /* write the data into mode register */
294 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
296 r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
297 dev->adapter.timeout);
298 if (r == 0) {
299 dev_err(dev->dev, "controller timed out\n");
300 i2c_davinci_init(dev);
301 dev->buf_len = 0;
302 return -ETIMEDOUT;
304 if (dev->buf_len) {
305 /* This should be 0 if all bytes were transferred
306 * or dev->cmd_err denotes an error.
307 * A signal may have aborted the transfer.
309 if (r >= 0) {
310 dev_err(dev->dev, "abnormal termination buf_len=%i\n",
311 dev->buf_len);
312 r = -EREMOTEIO;
314 dev->terminate = 1;
315 wmb();
316 dev->buf_len = 0;
318 if (r < 0)
319 return r;
321 /* no error */
322 if (likely(!dev->cmd_err))
323 return msg->len;
325 /* We have an error */
326 if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
327 i2c_davinci_init(dev);
328 return -EIO;
331 if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
332 if (msg->flags & I2C_M_IGNORE_NAK)
333 return msg->len;
334 if (stop) {
335 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
336 MOD_REG_BIT(w, DAVINCI_I2C_MDR_STP, 1);
337 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
339 return -EREMOTEIO;
341 return -EIO;
345 * Prepare controller for a transaction and call i2c_davinci_xfer_msg
347 static int
348 i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
350 struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
351 int i;
352 int ret;
354 dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
356 ret = i2c_davinci_wait_bus_not_busy(dev, 1);
357 if (ret < 0) {
358 dev_warn(dev->dev, "timeout waiting for bus ready\n");
359 return ret;
362 for (i = 0; i < num; i++) {
363 ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
364 dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
365 ret);
366 if (ret < 0)
367 return ret;
369 return num;
372 static u32 i2c_davinci_func(struct i2c_adapter *adap)
374 return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
377 static void terminate_read(struct davinci_i2c_dev *dev)
379 u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
380 w |= DAVINCI_I2C_MDR_NACK;
381 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
383 /* Throw away data */
384 davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG);
385 if (!dev->terminate)
386 dev_err(dev->dev, "RDR IRQ while no data requested\n");
388 static void terminate_write(struct davinci_i2c_dev *dev)
390 u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
391 w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP;
392 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
394 if (!dev->terminate)
395 dev_dbg(dev->dev, "TDR IRQ while no data to send\n");
399 * Interrupt service routine. This gets called whenever an I2C interrupt
400 * occurs.
402 static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
404 struct davinci_i2c_dev *dev = dev_id;
405 u32 stat;
406 int count = 0;
407 u16 w;
409 while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
410 dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
411 if (count++ == 100) {
412 dev_warn(dev->dev, "Too much work in one IRQ\n");
413 break;
416 switch (stat) {
417 case DAVINCI_I2C_IVR_AL:
418 /* Arbitration lost, must retry */
419 dev->cmd_err |= DAVINCI_I2C_STR_AL;
420 dev->buf_len = 0;
421 complete(&dev->cmd_complete);
422 break;
424 case DAVINCI_I2C_IVR_NACK:
425 dev->cmd_err |= DAVINCI_I2C_STR_NACK;
426 dev->buf_len = 0;
427 complete(&dev->cmd_complete);
428 break;
430 case DAVINCI_I2C_IVR_ARDY:
431 davinci_i2c_write_reg(dev,
432 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
433 complete(&dev->cmd_complete);
434 break;
436 case DAVINCI_I2C_IVR_RDR:
437 if (dev->buf_len) {
438 *dev->buf++ =
439 davinci_i2c_read_reg(dev,
440 DAVINCI_I2C_DRR_REG);
441 dev->buf_len--;
442 if (dev->buf_len)
443 continue;
445 davinci_i2c_write_reg(dev,
446 DAVINCI_I2C_STR_REG,
447 DAVINCI_I2C_IMR_RRDY);
448 } else {
449 /* signal can terminate transfer */
450 terminate_read(dev);
452 break;
454 case DAVINCI_I2C_IVR_XRDY:
455 if (dev->buf_len) {
456 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
457 *dev->buf++);
458 dev->buf_len--;
459 if (dev->buf_len)
460 continue;
462 w = davinci_i2c_read_reg(dev,
463 DAVINCI_I2C_IMR_REG);
464 MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 0);
465 davinci_i2c_write_reg(dev,
466 DAVINCI_I2C_IMR_REG,
468 } else {
469 /* signal can terminate transfer */
470 terminate_write(dev);
472 break;
474 case DAVINCI_I2C_IVR_SCD:
475 davinci_i2c_write_reg(dev,
476 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
477 complete(&dev->cmd_complete);
478 break;
480 case DAVINCI_I2C_IVR_AAS:
481 dev_dbg(dev->dev, "Address as slave interrupt\n");
482 break;
484 default:
485 dev_warn(dev->dev, "Unrecognized irq stat %d\n", stat);
486 break;
490 return count ? IRQ_HANDLED : IRQ_NONE;
493 static struct i2c_algorithm i2c_davinci_algo = {
494 .master_xfer = i2c_davinci_xfer,
495 .functionality = i2c_davinci_func,
498 static int davinci_i2c_probe(struct platform_device *pdev)
500 struct davinci_i2c_dev *dev;
501 struct i2c_adapter *adap;
502 struct resource *mem, *irq, *ioarea;
503 int r;
505 /* NOTE: driver uses the static register mapping */
506 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
507 if (!mem) {
508 dev_err(&pdev->dev, "no mem resource?\n");
509 return -ENODEV;
512 irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
513 if (!irq) {
514 dev_err(&pdev->dev, "no irq resource?\n");
515 return -ENODEV;
518 ioarea = request_mem_region(mem->start, resource_size(mem),
519 pdev->name);
520 if (!ioarea) {
521 dev_err(&pdev->dev, "I2C region already claimed\n");
522 return -EBUSY;
525 dev = kzalloc(sizeof(struct davinci_i2c_dev), GFP_KERNEL);
526 if (!dev) {
527 r = -ENOMEM;
528 goto err_release_region;
531 init_completion(&dev->cmd_complete);
532 dev->dev = get_device(&pdev->dev);
533 dev->irq = irq->start;
534 platform_set_drvdata(pdev, dev);
536 dev->clk = clk_get(&pdev->dev, NULL);
537 if (IS_ERR(dev->clk)) {
538 r = -ENODEV;
539 goto err_free_mem;
541 clk_enable(dev->clk);
543 dev->base = (void __iomem *)IO_ADDRESS(mem->start);
544 i2c_davinci_init(dev);
546 r = request_irq(dev->irq, i2c_davinci_isr, 0, pdev->name, dev);
547 if (r) {
548 dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
549 goto err_unuse_clocks;
552 adap = &dev->adapter;
553 i2c_set_adapdata(adap, dev);
554 adap->owner = THIS_MODULE;
555 adap->class = I2C_CLASS_HWMON;
556 strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
557 adap->algo = &i2c_davinci_algo;
558 adap->dev.parent = &pdev->dev;
559 adap->timeout = DAVINCI_I2C_TIMEOUT;
561 adap->nr = pdev->id;
562 r = i2c_add_numbered_adapter(adap);
563 if (r) {
564 dev_err(&pdev->dev, "failure adding adapter\n");
565 goto err_free_irq;
568 return 0;
570 err_free_irq:
571 free_irq(dev->irq, dev);
572 err_unuse_clocks:
573 clk_disable(dev->clk);
574 clk_put(dev->clk);
575 dev->clk = NULL;
576 err_free_mem:
577 platform_set_drvdata(pdev, NULL);
578 put_device(&pdev->dev);
579 kfree(dev);
580 err_release_region:
581 release_mem_region(mem->start, resource_size(mem));
583 return r;
586 static int davinci_i2c_remove(struct platform_device *pdev)
588 struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
589 struct resource *mem;
591 platform_set_drvdata(pdev, NULL);
592 i2c_del_adapter(&dev->adapter);
593 put_device(&pdev->dev);
595 clk_disable(dev->clk);
596 clk_put(dev->clk);
597 dev->clk = NULL;
599 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
600 free_irq(IRQ_I2C, dev);
601 kfree(dev);
603 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
604 release_mem_region(mem->start, resource_size(mem));
605 return 0;
608 /* work with hotplug and coldplug */
609 MODULE_ALIAS("platform:i2c_davinci");
611 static struct platform_driver davinci_i2c_driver = {
612 .probe = davinci_i2c_probe,
613 .remove = davinci_i2c_remove,
614 .driver = {
615 .name = "i2c_davinci",
616 .owner = THIS_MODULE,
620 /* I2C may be needed to bring up other drivers */
621 static int __init davinci_i2c_init_driver(void)
623 return platform_driver_register(&davinci_i2c_driver);
625 subsys_initcall(davinci_i2c_init_driver);
627 static void __exit davinci_i2c_exit_driver(void)
629 platform_driver_unregister(&davinci_i2c_driver);
631 module_exit(davinci_i2c_exit_driver);
633 MODULE_AUTHOR("Texas Instruments India");
634 MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
635 MODULE_LICENSE("GPL");