This source file includes following definitions.
- sprd_i2c_set_count
- sprd_i2c_send_stop
- sprd_i2c_clear_start
- sprd_i2c_clear_ack
- sprd_i2c_clear_irq
- sprd_i2c_reset_fifo
- sprd_i2c_set_devaddr
- sprd_i2c_write_bytes
- sprd_i2c_read_bytes
- sprd_i2c_set_full_thld
- sprd_i2c_set_empty_thld
- sprd_i2c_set_fifo_full_int
- sprd_i2c_set_fifo_empty_int
- sprd_i2c_opt_start
- sprd_i2c_opt_mode
- sprd_i2c_data_transfer
- sprd_i2c_handle_msg
- sprd_i2c_master_xfer
- sprd_i2c_func
- sprd_i2c_set_clk
- sprd_i2c_enable
- sprd_i2c_isr_thread
- sprd_i2c_isr
- sprd_i2c_clk_init
- sprd_i2c_probe
- sprd_i2c_remove
- sprd_i2c_suspend_noirq
- sprd_i2c_resume_noirq
- sprd_i2c_runtime_suspend
- sprd_i2c_runtime_resume
1
2
3
4
5
6
7 #include <linux/clk.h>
8 #include <linux/delay.h>
9 #include <linux/err.h>
10 #include <linux/io.h>
11 #include <linux/i2c.h>
12 #include <linux/init.h>
13 #include <linux/interrupt.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/platform_device.h>
19 #include <linux/pm_runtime.h>
20
21 #define I2C_CTL 0x00
22 #define I2C_ADDR_CFG 0x04
23 #define I2C_COUNT 0x08
24 #define I2C_RX 0x0c
25 #define I2C_TX 0x10
26 #define I2C_STATUS 0x14
27 #define I2C_HSMODE_CFG 0x18
28 #define I2C_VERSION 0x1c
29 #define ADDR_DVD0 0x20
30 #define ADDR_DVD1 0x24
31 #define ADDR_STA0_DVD 0x28
32 #define ADDR_RST 0x2c
33
34
35 #define STP_EN BIT(20)
36 #define FIFO_AF_LVL_MASK GENMASK(19, 16)
37 #define FIFO_AF_LVL 16
38 #define FIFO_AE_LVL_MASK GENMASK(15, 12)
39 #define FIFO_AE_LVL 12
40 #define I2C_DMA_EN BIT(11)
41 #define FULL_INTEN BIT(10)
42 #define EMPTY_INTEN BIT(9)
43 #define I2C_DVD_OPT BIT(8)
44 #define I2C_OUT_OPT BIT(7)
45 #define I2C_TRIM_OPT BIT(6)
46 #define I2C_HS_MODE BIT(4)
47 #define I2C_MODE BIT(3)
48 #define I2C_EN BIT(2)
49 #define I2C_INT_EN BIT(1)
50 #define I2C_START BIT(0)
51
52
53 #define SDA_IN BIT(21)
54 #define SCL_IN BIT(20)
55 #define FIFO_FULL BIT(4)
56 #define FIFO_EMPTY BIT(3)
57 #define I2C_INT BIT(2)
58 #define I2C_RX_ACK BIT(1)
59 #define I2C_BUSY BIT(0)
60
61
62 #define I2C_RST BIT(0)
63
64 #define I2C_FIFO_DEEP 12
65 #define I2C_FIFO_FULL_THLD 15
66 #define I2C_FIFO_EMPTY_THLD 4
67 #define I2C_DATA_STEP 8
68 #define I2C_ADDR_DVD0_CALC(high, low) \
69 ((((high) & GENMASK(15, 0)) << 16) | ((low) & GENMASK(15, 0)))
70 #define I2C_ADDR_DVD1_CALC(high, low) \
71 (((high) & GENMASK(31, 16)) | (((low) & GENMASK(31, 16)) >> 16))
72
73
74 #define SPRD_I2C_PM_TIMEOUT 1000
75
76
77 struct sprd_i2c {
78 struct i2c_adapter adap;
79 struct device *dev;
80 void __iomem *base;
81 struct i2c_msg *msg;
82 struct clk *clk;
83 u32 src_clk;
84 u32 bus_freq;
85 struct completion complete;
86 u8 *buf;
87 u32 count;
88 int irq;
89 int err;
90 };
91
92 static void sprd_i2c_set_count(struct sprd_i2c *i2c_dev, u32 count)
93 {
94 writel(count, i2c_dev->base + I2C_COUNT);
95 }
96
97 static void sprd_i2c_send_stop(struct sprd_i2c *i2c_dev, int stop)
98 {
99 u32 tmp = readl(i2c_dev->base + I2C_CTL);
100
101 if (stop)
102 writel(tmp & ~STP_EN, i2c_dev->base + I2C_CTL);
103 else
104 writel(tmp | STP_EN, i2c_dev->base + I2C_CTL);
105 }
106
107 static void sprd_i2c_clear_start(struct sprd_i2c *i2c_dev)
108 {
109 u32 tmp = readl(i2c_dev->base + I2C_CTL);
110
111 writel(tmp & ~I2C_START, i2c_dev->base + I2C_CTL);
112 }
113
114 static void sprd_i2c_clear_ack(struct sprd_i2c *i2c_dev)
115 {
116 u32 tmp = readl(i2c_dev->base + I2C_STATUS);
117
118 writel(tmp & ~I2C_RX_ACK, i2c_dev->base + I2C_STATUS);
119 }
120
121 static void sprd_i2c_clear_irq(struct sprd_i2c *i2c_dev)
122 {
123 u32 tmp = readl(i2c_dev->base + I2C_STATUS);
124
125 writel(tmp & ~I2C_INT, i2c_dev->base + I2C_STATUS);
126 }
127
128 static void sprd_i2c_reset_fifo(struct sprd_i2c *i2c_dev)
129 {
130 writel(I2C_RST, i2c_dev->base + ADDR_RST);
131 }
132
133 static void sprd_i2c_set_devaddr(struct sprd_i2c *i2c_dev, struct i2c_msg *m)
134 {
135 writel(m->addr << 1, i2c_dev->base + I2C_ADDR_CFG);
136 }
137
138 static void sprd_i2c_write_bytes(struct sprd_i2c *i2c_dev, u8 *buf, u32 len)
139 {
140 u32 i;
141
142 for (i = 0; i < len; i++)
143 writeb(buf[i], i2c_dev->base + I2C_TX);
144 }
145
146 static void sprd_i2c_read_bytes(struct sprd_i2c *i2c_dev, u8 *buf, u32 len)
147 {
148 u32 i;
149
150 for (i = 0; i < len; i++)
151 buf[i] = readb(i2c_dev->base + I2C_RX);
152 }
153
154 static void sprd_i2c_set_full_thld(struct sprd_i2c *i2c_dev, u32 full_thld)
155 {
156 u32 tmp = readl(i2c_dev->base + I2C_CTL);
157
158 tmp &= ~FIFO_AF_LVL_MASK;
159 tmp |= full_thld << FIFO_AF_LVL;
160 writel(tmp, i2c_dev->base + I2C_CTL);
161 };
162
163 static void sprd_i2c_set_empty_thld(struct sprd_i2c *i2c_dev, u32 empty_thld)
164 {
165 u32 tmp = readl(i2c_dev->base + I2C_CTL);
166
167 tmp &= ~FIFO_AE_LVL_MASK;
168 tmp |= empty_thld << FIFO_AE_LVL;
169 writel(tmp, i2c_dev->base + I2C_CTL);
170 };
171
172 static void sprd_i2c_set_fifo_full_int(struct sprd_i2c *i2c_dev, int enable)
173 {
174 u32 tmp = readl(i2c_dev->base + I2C_CTL);
175
176 if (enable)
177 tmp |= FULL_INTEN;
178 else
179 tmp &= ~FULL_INTEN;
180
181 writel(tmp, i2c_dev->base + I2C_CTL);
182 };
183
184 static void sprd_i2c_set_fifo_empty_int(struct sprd_i2c *i2c_dev, int enable)
185 {
186 u32 tmp = readl(i2c_dev->base + I2C_CTL);
187
188 if (enable)
189 tmp |= EMPTY_INTEN;
190 else
191 tmp &= ~EMPTY_INTEN;
192
193 writel(tmp, i2c_dev->base + I2C_CTL);
194 };
195
196 static void sprd_i2c_opt_start(struct sprd_i2c *i2c_dev)
197 {
198 u32 tmp = readl(i2c_dev->base + I2C_CTL);
199
200 writel(tmp | I2C_START, i2c_dev->base + I2C_CTL);
201 }
202
203 static void sprd_i2c_opt_mode(struct sprd_i2c *i2c_dev, int rw)
204 {
205 u32 cmd = readl(i2c_dev->base + I2C_CTL) & ~I2C_MODE;
206
207 writel(cmd | rw << 3, i2c_dev->base + I2C_CTL);
208 }
209
210 static void sprd_i2c_data_transfer(struct sprd_i2c *i2c_dev)
211 {
212 u32 i2c_count = i2c_dev->count;
213 u32 need_tran = i2c_count <= I2C_FIFO_DEEP ? i2c_count : I2C_FIFO_DEEP;
214 struct i2c_msg *msg = i2c_dev->msg;
215
216 if (msg->flags & I2C_M_RD) {
217 sprd_i2c_read_bytes(i2c_dev, i2c_dev->buf, I2C_FIFO_FULL_THLD);
218 i2c_dev->count -= I2C_FIFO_FULL_THLD;
219 i2c_dev->buf += I2C_FIFO_FULL_THLD;
220
221
222
223
224
225
226 if (i2c_dev->count >= I2C_FIFO_FULL_THLD)
227 sprd_i2c_set_fifo_full_int(i2c_dev, 1);
228 } else {
229 sprd_i2c_write_bytes(i2c_dev, i2c_dev->buf, need_tran);
230 i2c_dev->buf += need_tran;
231 i2c_dev->count -= need_tran;
232
233
234
235
236
237
238 if (i2c_count > I2C_FIFO_DEEP)
239 sprd_i2c_set_fifo_empty_int(i2c_dev, 1);
240 }
241 }
242
243 static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap,
244 struct i2c_msg *msg, bool is_last_msg)
245 {
246 struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
247
248 i2c_dev->msg = msg;
249 i2c_dev->buf = msg->buf;
250 i2c_dev->count = msg->len;
251
252 reinit_completion(&i2c_dev->complete);
253 sprd_i2c_reset_fifo(i2c_dev);
254 sprd_i2c_set_devaddr(i2c_dev, msg);
255 sprd_i2c_set_count(i2c_dev, msg->len);
256
257 if (msg->flags & I2C_M_RD) {
258 sprd_i2c_opt_mode(i2c_dev, 1);
259 sprd_i2c_send_stop(i2c_dev, 1);
260 } else {
261 sprd_i2c_opt_mode(i2c_dev, 0);
262 sprd_i2c_send_stop(i2c_dev, !!is_last_msg);
263 }
264
265
266
267
268
269 if (msg->flags & I2C_M_RD)
270 sprd_i2c_set_fifo_full_int(i2c_dev, 1);
271 else
272 sprd_i2c_data_transfer(i2c_dev);
273
274 sprd_i2c_opt_start(i2c_dev);
275
276 wait_for_completion(&i2c_dev->complete);
277
278 return i2c_dev->err;
279 }
280
281 static int sprd_i2c_master_xfer(struct i2c_adapter *i2c_adap,
282 struct i2c_msg *msgs, int num)
283 {
284 struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
285 int im, ret;
286
287 ret = pm_runtime_get_sync(i2c_dev->dev);
288 if (ret < 0)
289 return ret;
290
291 for (im = 0; im < num - 1; im++) {
292 ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im], 0);
293 if (ret)
294 goto err_msg;
295 }
296
297 ret = sprd_i2c_handle_msg(i2c_adap, &msgs[im++], 1);
298
299 err_msg:
300 pm_runtime_mark_last_busy(i2c_dev->dev);
301 pm_runtime_put_autosuspend(i2c_dev->dev);
302
303 return ret < 0 ? ret : im;
304 }
305
306 static u32 sprd_i2c_func(struct i2c_adapter *adap)
307 {
308 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
309 }
310
311 static const struct i2c_algorithm sprd_i2c_algo = {
312 .master_xfer = sprd_i2c_master_xfer,
313 .functionality = sprd_i2c_func,
314 };
315
316 static void sprd_i2c_set_clk(struct sprd_i2c *i2c_dev, u32 freq)
317 {
318 u32 apb_clk = i2c_dev->src_clk;
319
320
321
322
323 u32 i2c_dvd = apb_clk / (4 * freq) - 1;
324
325
326
327
328
329
330
331 u32 high = ((i2c_dvd << 1) * 2) / 5;
332 u32 low = ((i2c_dvd << 1) * 3) / 5;
333 u32 div0 = I2C_ADDR_DVD0_CALC(high, low);
334 u32 div1 = I2C_ADDR_DVD1_CALC(high, low);
335
336 writel(div0, i2c_dev->base + ADDR_DVD0);
337 writel(div1, i2c_dev->base + ADDR_DVD1);
338
339
340 if (freq == 400000)
341 writel((6 * apb_clk) / 10000000, i2c_dev->base + ADDR_STA0_DVD);
342 else if (freq == 100000)
343 writel((4 * apb_clk) / 1000000, i2c_dev->base + ADDR_STA0_DVD);
344 }
345
346 static void sprd_i2c_enable(struct sprd_i2c *i2c_dev)
347 {
348 u32 tmp = I2C_DVD_OPT;
349
350 writel(tmp, i2c_dev->base + I2C_CTL);
351
352 sprd_i2c_set_full_thld(i2c_dev, I2C_FIFO_FULL_THLD);
353 sprd_i2c_set_empty_thld(i2c_dev, I2C_FIFO_EMPTY_THLD);
354
355 sprd_i2c_set_clk(i2c_dev, i2c_dev->bus_freq);
356 sprd_i2c_reset_fifo(i2c_dev);
357 sprd_i2c_clear_irq(i2c_dev);
358
359 tmp = readl(i2c_dev->base + I2C_CTL);
360 writel(tmp | I2C_EN | I2C_INT_EN, i2c_dev->base + I2C_CTL);
361 }
362
363 static irqreturn_t sprd_i2c_isr_thread(int irq, void *dev_id)
364 {
365 struct sprd_i2c *i2c_dev = dev_id;
366 struct i2c_msg *msg = i2c_dev->msg;
367 bool ack = !(readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK);
368 u32 i2c_tran;
369
370 if (msg->flags & I2C_M_RD)
371 i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD;
372 else
373 i2c_tran = i2c_dev->count;
374
375
376
377
378
379
380
381
382
383 if (i2c_tran && ack) {
384 sprd_i2c_data_transfer(i2c_dev);
385 return IRQ_HANDLED;
386 }
387
388 i2c_dev->err = 0;
389
390
391
392
393
394 if (!ack)
395 i2c_dev->err = -EIO;
396 else if (msg->flags & I2C_M_RD && i2c_dev->count)
397 sprd_i2c_read_bytes(i2c_dev, i2c_dev->buf, i2c_dev->count);
398
399
400 sprd_i2c_clear_ack(i2c_dev);
401 sprd_i2c_clear_start(i2c_dev);
402 complete(&i2c_dev->complete);
403
404 return IRQ_HANDLED;
405 }
406
407 static irqreturn_t sprd_i2c_isr(int irq, void *dev_id)
408 {
409 struct sprd_i2c *i2c_dev = dev_id;
410 struct i2c_msg *msg = i2c_dev->msg;
411 bool ack = !(readl(i2c_dev->base + I2C_STATUS) & I2C_RX_ACK);
412 u32 i2c_tran;
413
414 if (msg->flags & I2C_M_RD)
415 i2c_tran = i2c_dev->count >= I2C_FIFO_FULL_THLD;
416 else
417 i2c_tran = i2c_dev->count;
418
419
420
421
422
423
424
425
426
427
428
429
430 if (!i2c_tran || !ack) {
431 sprd_i2c_clear_start(i2c_dev);
432 sprd_i2c_clear_irq(i2c_dev);
433 }
434
435 sprd_i2c_set_fifo_empty_int(i2c_dev, 0);
436 sprd_i2c_set_fifo_full_int(i2c_dev, 0);
437
438 return IRQ_WAKE_THREAD;
439 }
440
441 static int sprd_i2c_clk_init(struct sprd_i2c *i2c_dev)
442 {
443 struct clk *clk_i2c, *clk_parent;
444
445 clk_i2c = devm_clk_get(i2c_dev->dev, "i2c");
446 if (IS_ERR(clk_i2c)) {
447 dev_warn(i2c_dev->dev, "i2c%d can't get the i2c clock\n",
448 i2c_dev->adap.nr);
449 clk_i2c = NULL;
450 }
451
452 clk_parent = devm_clk_get(i2c_dev->dev, "source");
453 if (IS_ERR(clk_parent)) {
454 dev_warn(i2c_dev->dev, "i2c%d can't get the source clock\n",
455 i2c_dev->adap.nr);
456 clk_parent = NULL;
457 }
458
459 if (clk_set_parent(clk_i2c, clk_parent))
460 i2c_dev->src_clk = clk_get_rate(clk_i2c);
461 else
462 i2c_dev->src_clk = 26000000;
463
464 dev_dbg(i2c_dev->dev, "i2c%d set source clock is %d\n",
465 i2c_dev->adap.nr, i2c_dev->src_clk);
466
467 i2c_dev->clk = devm_clk_get(i2c_dev->dev, "enable");
468 if (IS_ERR(i2c_dev->clk)) {
469 dev_err(i2c_dev->dev, "i2c%d can't get the enable clock\n",
470 i2c_dev->adap.nr);
471 return PTR_ERR(i2c_dev->clk);
472 }
473
474 return 0;
475 }
476
477 static int sprd_i2c_probe(struct platform_device *pdev)
478 {
479 struct device *dev = &pdev->dev;
480 struct sprd_i2c *i2c_dev;
481 u32 prop;
482 int ret;
483
484 pdev->id = of_alias_get_id(dev->of_node, "i2c");
485
486 i2c_dev = devm_kzalloc(dev, sizeof(struct sprd_i2c), GFP_KERNEL);
487 if (!i2c_dev)
488 return -ENOMEM;
489
490 i2c_dev->base = devm_platform_ioremap_resource(pdev, 0);
491 if (IS_ERR(i2c_dev->base))
492 return PTR_ERR(i2c_dev->base);
493
494 i2c_dev->irq = platform_get_irq(pdev, 0);
495 if (i2c_dev->irq < 0) {
496 dev_err(&pdev->dev, "failed to get irq resource\n");
497 return i2c_dev->irq;
498 }
499
500 i2c_set_adapdata(&i2c_dev->adap, i2c_dev);
501 init_completion(&i2c_dev->complete);
502 snprintf(i2c_dev->adap.name, sizeof(i2c_dev->adap.name),
503 "%s", "sprd-i2c");
504
505 i2c_dev->bus_freq = 100000;
506 i2c_dev->adap.owner = THIS_MODULE;
507 i2c_dev->dev = dev;
508 i2c_dev->adap.retries = 3;
509 i2c_dev->adap.algo = &sprd_i2c_algo;
510 i2c_dev->adap.algo_data = i2c_dev;
511 i2c_dev->adap.dev.parent = dev;
512 i2c_dev->adap.nr = pdev->id;
513 i2c_dev->adap.dev.of_node = dev->of_node;
514
515 if (!of_property_read_u32(dev->of_node, "clock-frequency", &prop))
516 i2c_dev->bus_freq = prop;
517
518
519 if (i2c_dev->bus_freq != 100000 && i2c_dev->bus_freq != 400000)
520 return -EINVAL;
521
522 ret = sprd_i2c_clk_init(i2c_dev);
523 if (ret)
524 return ret;
525
526 platform_set_drvdata(pdev, i2c_dev);
527
528 ret = clk_prepare_enable(i2c_dev->clk);
529 if (ret)
530 return ret;
531
532 sprd_i2c_enable(i2c_dev);
533
534 pm_runtime_set_autosuspend_delay(i2c_dev->dev, SPRD_I2C_PM_TIMEOUT);
535 pm_runtime_use_autosuspend(i2c_dev->dev);
536 pm_runtime_set_active(i2c_dev->dev);
537 pm_runtime_enable(i2c_dev->dev);
538
539 ret = pm_runtime_get_sync(i2c_dev->dev);
540 if (ret < 0)
541 goto err_rpm_put;
542
543 ret = devm_request_threaded_irq(dev, i2c_dev->irq,
544 sprd_i2c_isr, sprd_i2c_isr_thread,
545 IRQF_NO_SUSPEND | IRQF_ONESHOT,
546 pdev->name, i2c_dev);
547 if (ret) {
548 dev_err(&pdev->dev, "failed to request irq %d\n", i2c_dev->irq);
549 goto err_rpm_put;
550 }
551
552 ret = i2c_add_numbered_adapter(&i2c_dev->adap);
553 if (ret) {
554 dev_err(&pdev->dev, "add adapter failed\n");
555 goto err_rpm_put;
556 }
557
558 pm_runtime_mark_last_busy(i2c_dev->dev);
559 pm_runtime_put_autosuspend(i2c_dev->dev);
560 return 0;
561
562 err_rpm_put:
563 pm_runtime_put_noidle(i2c_dev->dev);
564 pm_runtime_disable(i2c_dev->dev);
565 clk_disable_unprepare(i2c_dev->clk);
566 return ret;
567 }
568
569 static int sprd_i2c_remove(struct platform_device *pdev)
570 {
571 struct sprd_i2c *i2c_dev = platform_get_drvdata(pdev);
572 int ret;
573
574 ret = pm_runtime_get_sync(i2c_dev->dev);
575 if (ret < 0)
576 return ret;
577
578 i2c_del_adapter(&i2c_dev->adap);
579 clk_disable_unprepare(i2c_dev->clk);
580
581 pm_runtime_put_noidle(i2c_dev->dev);
582 pm_runtime_disable(i2c_dev->dev);
583
584 return 0;
585 }
586
587 static int __maybe_unused sprd_i2c_suspend_noirq(struct device *dev)
588 {
589 struct sprd_i2c *i2c_dev = dev_get_drvdata(dev);
590
591 i2c_mark_adapter_suspended(&i2c_dev->adap);
592 return pm_runtime_force_suspend(dev);
593 }
594
595 static int __maybe_unused sprd_i2c_resume_noirq(struct device *dev)
596 {
597 struct sprd_i2c *i2c_dev = dev_get_drvdata(dev);
598
599 i2c_mark_adapter_resumed(&i2c_dev->adap);
600 return pm_runtime_force_resume(dev);
601 }
602
603 static int __maybe_unused sprd_i2c_runtime_suspend(struct device *dev)
604 {
605 struct sprd_i2c *i2c_dev = dev_get_drvdata(dev);
606
607 clk_disable_unprepare(i2c_dev->clk);
608
609 return 0;
610 }
611
612 static int __maybe_unused sprd_i2c_runtime_resume(struct device *dev)
613 {
614 struct sprd_i2c *i2c_dev = dev_get_drvdata(dev);
615 int ret;
616
617 ret = clk_prepare_enable(i2c_dev->clk);
618 if (ret)
619 return ret;
620
621 sprd_i2c_enable(i2c_dev);
622
623 return 0;
624 }
625
626 static const struct dev_pm_ops sprd_i2c_pm_ops = {
627 SET_RUNTIME_PM_OPS(sprd_i2c_runtime_suspend,
628 sprd_i2c_runtime_resume, NULL)
629
630 SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(sprd_i2c_suspend_noirq,
631 sprd_i2c_resume_noirq)
632 };
633
634 static const struct of_device_id sprd_i2c_of_match[] = {
635 { .compatible = "sprd,sc9860-i2c", },
636 {},
637 };
638
639 static struct platform_driver sprd_i2c_driver = {
640 .probe = sprd_i2c_probe,
641 .remove = sprd_i2c_remove,
642 .driver = {
643 .name = "sprd-i2c",
644 .of_match_table = sprd_i2c_of_match,
645 .pm = &sprd_i2c_pm_ops,
646 },
647 };
648
649 module_platform_driver(sprd_i2c_driver);
650
651 MODULE_DESCRIPTION("Spreadtrum I2C master controller driver");
652 MODULE_LICENSE("GPL v2");