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12#include <linux/clk.h>
13#include <linux/i2c.h>
14#include <linux/interrupt.h>
15#include <linux/io.h>
16#include <linux/module.h>
17#include <linux/platform_device.h>
18
19#define REG_CMD 0x04
20#define REG_DEVADDR_H 0x0C
21#define REG_DEVADDR_L 0x10
22#define REG_CLK_DIV_FS 0x14
23#define REG_CLK_DIV_HS 0x18
24#define REG_WRCONF 0x1C
25#define REG_RDCONF 0x20
26#define REG_DATA 0x24
27#define REG_STAT 0x28
28
29#define I2C_STOP 0
30#define I2C_MASTER BIT(0)
31#define I2C_ADDR_MODE_TEN BIT(1)
32#define I2C_IRQ_MSK_ENABLE BIT(3)
33#define I2C_RW_READ BIT(4)
34#define I2C_CMB_RW_EN BIT(5)
35#define I2C_START BIT(6)
36
37#define I2C_ADDR_LOW_MASK GENMASK(6, 0)
38#define I2C_ADDR_LOW_SHIFT 0
39#define I2C_ADDR_HI_MASK GENMASK(2, 0)
40#define I2C_ADDR_HI_SHIFT 7
41
42#define I2C_WFIFO_RESET BIT(7)
43#define I2C_RFIFO_RESET BIT(7)
44
45#define I2C_IRQ_ACK_CLEAR BIT(7)
46#define I2C_INT_MASK GENMASK(6, 0)
47
48#define I2C_TRANS_DONE BIT(0)
49#define I2C_SR_EDEVICE BIT(1)
50#define I2C_SR_EDATA BIT(2)
51
52#define I2C_FIFO_MAX 16
53
54#define I2C_TIMEOUT msecs_to_jiffies(1000)
55
56#define DEV(i2c) ((i2c)->adap.dev.parent)
57
58struct zx2967_i2c {
59 struct i2c_adapter adap;
60 struct clk *clk;
61 struct completion complete;
62 u32 clk_freq;
63 void __iomem *reg_base;
64 size_t residue;
65 int irq;
66 int msg_rd;
67 u8 *cur_trans;
68 u8 access_cnt;
69 bool is_suspended;
70 int error;
71};
72
73static void zx2967_i2c_writel(struct zx2967_i2c *i2c,
74 u32 val, unsigned long reg)
75{
76 writel_relaxed(val, i2c->reg_base + reg);
77}
78
79static u32 zx2967_i2c_readl(struct zx2967_i2c *i2c, unsigned long reg)
80{
81 return readl_relaxed(i2c->reg_base + reg);
82}
83
84static void zx2967_i2c_writesb(struct zx2967_i2c *i2c,
85 void *data, unsigned long reg, int len)
86{
87 writesb(i2c->reg_base + reg, data, len);
88}
89
90static void zx2967_i2c_readsb(struct zx2967_i2c *i2c,
91 void *data, unsigned long reg, int len)
92{
93 readsb(i2c->reg_base + reg, data, len);
94}
95
96static void zx2967_i2c_start_ctrl(struct zx2967_i2c *i2c)
97{
98 u32 status;
99 u32 ctl;
100
101 status = zx2967_i2c_readl(i2c, REG_STAT);
102 status |= I2C_IRQ_ACK_CLEAR;
103 zx2967_i2c_writel(i2c, status, REG_STAT);
104
105 ctl = zx2967_i2c_readl(i2c, REG_CMD);
106 if (i2c->msg_rd)
107 ctl |= I2C_RW_READ;
108 else
109 ctl &= ~I2C_RW_READ;
110 ctl &= ~I2C_CMB_RW_EN;
111 ctl |= I2C_START;
112 zx2967_i2c_writel(i2c, ctl, REG_CMD);
113}
114
115static void zx2967_i2c_flush_fifos(struct zx2967_i2c *i2c)
116{
117 u32 offset;
118 u32 val;
119
120 if (i2c->msg_rd) {
121 offset = REG_RDCONF;
122 val = I2C_RFIFO_RESET;
123 } else {
124 offset = REG_WRCONF;
125 val = I2C_WFIFO_RESET;
126 }
127
128 val |= zx2967_i2c_readl(i2c, offset);
129 zx2967_i2c_writel(i2c, val, offset);
130}
131
132static int zx2967_i2c_empty_rx_fifo(struct zx2967_i2c *i2c, u32 size)
133{
134 u8 val[I2C_FIFO_MAX] = {0};
135 int i;
136
137 if (size > I2C_FIFO_MAX) {
138 dev_err(DEV(i2c), "fifo size %d over the max value %d\n",
139 size, I2C_FIFO_MAX);
140 return -EINVAL;
141 }
142
143 zx2967_i2c_readsb(i2c, val, REG_DATA, size);
144 for (i = 0; i < size; i++) {
145 *i2c->cur_trans++ = val[i];
146 i2c->residue--;
147 }
148
149 barrier();
150
151 return 0;
152}
153
154static int zx2967_i2c_fill_tx_fifo(struct zx2967_i2c *i2c)
155{
156 size_t residue = i2c->residue;
157 u8 *buf = i2c->cur_trans;
158
159 if (residue == 0) {
160 dev_err(DEV(i2c), "residue is %d\n", (int)residue);
161 return -EINVAL;
162 }
163
164 if (residue <= I2C_FIFO_MAX) {
165 zx2967_i2c_writesb(i2c, buf, REG_DATA, residue);
166
167
168 i2c->residue = 0;
169 i2c->cur_trans = NULL;
170 } else {
171 zx2967_i2c_writesb(i2c, buf, REG_DATA, I2C_FIFO_MAX);
172 i2c->residue -= I2C_FIFO_MAX;
173 i2c->cur_trans += I2C_FIFO_MAX;
174 }
175
176 barrier();
177
178 return 0;
179}
180
181static int zx2967_i2c_reset_hardware(struct zx2967_i2c *i2c)
182{
183 u32 val;
184 u32 clk_div;
185
186 val = I2C_MASTER | I2C_IRQ_MSK_ENABLE;
187 zx2967_i2c_writel(i2c, val, REG_CMD);
188
189 clk_div = clk_get_rate(i2c->clk) / i2c->clk_freq - 1;
190 zx2967_i2c_writel(i2c, clk_div, REG_CLK_DIV_FS);
191 zx2967_i2c_writel(i2c, clk_div, REG_CLK_DIV_HS);
192
193 zx2967_i2c_writel(i2c, I2C_FIFO_MAX - 1, REG_WRCONF);
194 zx2967_i2c_writel(i2c, I2C_FIFO_MAX - 1, REG_RDCONF);
195 zx2967_i2c_writel(i2c, 1, REG_RDCONF);
196
197 zx2967_i2c_flush_fifos(i2c);
198
199 return 0;
200}
201
202static void zx2967_i2c_isr_clr(struct zx2967_i2c *i2c)
203{
204 u32 status;
205
206 status = zx2967_i2c_readl(i2c, REG_STAT);
207 status |= I2C_IRQ_ACK_CLEAR;
208 zx2967_i2c_writel(i2c, status, REG_STAT);
209}
210
211static irqreturn_t zx2967_i2c_isr(int irq, void *dev_id)
212{
213 u32 status;
214 struct zx2967_i2c *i2c = (struct zx2967_i2c *)dev_id;
215
216 status = zx2967_i2c_readl(i2c, REG_STAT) & I2C_INT_MASK;
217 zx2967_i2c_isr_clr(i2c);
218
219 if (status & I2C_SR_EDEVICE)
220 i2c->error = -ENXIO;
221 else if (status & I2C_SR_EDATA)
222 i2c->error = -EIO;
223 else if (status & I2C_TRANS_DONE)
224 i2c->error = 0;
225 else
226 goto done;
227
228 complete(&i2c->complete);
229done:
230 return IRQ_HANDLED;
231}
232
233static void zx2967_set_addr(struct zx2967_i2c *i2c, u16 addr)
234{
235 u16 val;
236
237 val = (addr >> I2C_ADDR_LOW_SHIFT) & I2C_ADDR_LOW_MASK;
238 zx2967_i2c_writel(i2c, val, REG_DEVADDR_L);
239
240 val = (addr >> I2C_ADDR_HI_SHIFT) & I2C_ADDR_HI_MASK;
241 zx2967_i2c_writel(i2c, val, REG_DEVADDR_H);
242 if (val)
243 val = zx2967_i2c_readl(i2c, REG_CMD) | I2C_ADDR_MODE_TEN;
244 else
245 val = zx2967_i2c_readl(i2c, REG_CMD) & ~I2C_ADDR_MODE_TEN;
246 zx2967_i2c_writel(i2c, val, REG_CMD);
247}
248
249static int zx2967_i2c_xfer_bytes(struct zx2967_i2c *i2c, u32 bytes)
250{
251 unsigned long time_left;
252 int rd = i2c->msg_rd;
253 int ret;
254
255 reinit_completion(&i2c->complete);
256
257 if (rd) {
258 zx2967_i2c_writel(i2c, bytes - 1, REG_RDCONF);
259 } else {
260 ret = zx2967_i2c_fill_tx_fifo(i2c);
261 if (ret)
262 return ret;
263 }
264
265 zx2967_i2c_start_ctrl(i2c);
266
267 time_left = wait_for_completion_timeout(&i2c->complete,
268 I2C_TIMEOUT);
269 if (time_left == 0)
270 return -ETIMEDOUT;
271
272 if (i2c->error)
273 return i2c->error;
274
275 return rd ? zx2967_i2c_empty_rx_fifo(i2c, bytes) : 0;
276}
277
278static int zx2967_i2c_xfer_msg(struct zx2967_i2c *i2c,
279 struct i2c_msg *msg)
280{
281 int ret;
282 int i;
283
284 if (msg->len == 0)
285 return -EINVAL;
286
287 zx2967_i2c_flush_fifos(i2c);
288
289 i2c->cur_trans = msg->buf;
290 i2c->residue = msg->len;
291 i2c->access_cnt = msg->len / I2C_FIFO_MAX;
292 i2c->msg_rd = msg->flags & I2C_M_RD;
293
294 for (i = 0; i < i2c->access_cnt; i++) {
295 ret = zx2967_i2c_xfer_bytes(i2c, I2C_FIFO_MAX);
296 if (ret)
297 return ret;
298 }
299
300 if (i2c->residue > 0) {
301 ret = zx2967_i2c_xfer_bytes(i2c, i2c->residue);
302 if (ret)
303 return ret;
304 }
305
306 i2c->residue = 0;
307 i2c->access_cnt = 0;
308
309 return 0;
310}
311
312static int zx2967_i2c_xfer(struct i2c_adapter *adap,
313 struct i2c_msg *msgs, int num)
314{
315 struct zx2967_i2c *i2c = i2c_get_adapdata(adap);
316 int ret;
317 int i;
318
319 if (i2c->is_suspended)
320 return -EBUSY;
321
322 zx2967_set_addr(i2c, msgs->addr);
323
324 for (i = 0; i < num; i++) {
325 ret = zx2967_i2c_xfer_msg(i2c, &msgs[i]);
326 if (ret)
327 return ret;
328 }
329
330 return num;
331}
332
333static void
334zx2967_smbus_xfer_prepare(struct zx2967_i2c *i2c, u16 addr,
335 char read_write, u8 command, int size,
336 union i2c_smbus_data *data)
337{
338 u32 val;
339
340 val = zx2967_i2c_readl(i2c, REG_RDCONF);
341 val |= I2C_RFIFO_RESET;
342 zx2967_i2c_writel(i2c, val, REG_RDCONF);
343 zx2967_set_addr(i2c, addr);
344 val = zx2967_i2c_readl(i2c, REG_CMD);
345 val &= ~I2C_RW_READ;
346 zx2967_i2c_writel(i2c, val, REG_CMD);
347
348 switch (size) {
349 case I2C_SMBUS_BYTE:
350 zx2967_i2c_writel(i2c, command, REG_DATA);
351 break;
352 case I2C_SMBUS_BYTE_DATA:
353 zx2967_i2c_writel(i2c, command, REG_DATA);
354 if (read_write == I2C_SMBUS_WRITE)
355 zx2967_i2c_writel(i2c, data->byte, REG_DATA);
356 break;
357 case I2C_SMBUS_WORD_DATA:
358 zx2967_i2c_writel(i2c, command, REG_DATA);
359 if (read_write == I2C_SMBUS_WRITE) {
360 zx2967_i2c_writel(i2c, (data->word >> 8), REG_DATA);
361 zx2967_i2c_writel(i2c, (data->word & 0xff),
362 REG_DATA);
363 }
364 break;
365 }
366}
367
368static int zx2967_smbus_xfer_read(struct zx2967_i2c *i2c, int size,
369 union i2c_smbus_data *data)
370{
371 unsigned long time_left;
372 u8 buf[2];
373 u32 val;
374
375 reinit_completion(&i2c->complete);
376
377 val = zx2967_i2c_readl(i2c, REG_CMD);
378 val |= I2C_CMB_RW_EN;
379 zx2967_i2c_writel(i2c, val, REG_CMD);
380
381 val = zx2967_i2c_readl(i2c, REG_CMD);
382 val |= I2C_START;
383 zx2967_i2c_writel(i2c, val, REG_CMD);
384
385 time_left = wait_for_completion_timeout(&i2c->complete,
386 I2C_TIMEOUT);
387 if (time_left == 0)
388 return -ETIMEDOUT;
389
390 if (i2c->error)
391 return i2c->error;
392
393 switch (size) {
394 case I2C_SMBUS_BYTE:
395 case I2C_SMBUS_BYTE_DATA:
396 val = zx2967_i2c_readl(i2c, REG_DATA);
397 data->byte = val;
398 break;
399 case I2C_SMBUS_WORD_DATA:
400 case I2C_SMBUS_PROC_CALL:
401 buf[0] = zx2967_i2c_readl(i2c, REG_DATA);
402 buf[1] = zx2967_i2c_readl(i2c, REG_DATA);
403 data->word = (buf[0] << 8) | buf[1];
404 break;
405 default:
406 return -EOPNOTSUPP;
407 }
408
409 return 0;
410}
411
412static int zx2967_smbus_xfer_write(struct zx2967_i2c *i2c)
413{
414 unsigned long time_left;
415 u32 val;
416
417 reinit_completion(&i2c->complete);
418 val = zx2967_i2c_readl(i2c, REG_CMD);
419 val |= I2C_START;
420 zx2967_i2c_writel(i2c, val, REG_CMD);
421
422 time_left = wait_for_completion_timeout(&i2c->complete,
423 I2C_TIMEOUT);
424 if (time_left == 0)
425 return -ETIMEDOUT;
426
427 if (i2c->error)
428 return i2c->error;
429
430 return 0;
431}
432
433static int zx2967_smbus_xfer(struct i2c_adapter *adap, u16 addr,
434 unsigned short flags, char read_write,
435 u8 command, int size, union i2c_smbus_data *data)
436{
437 struct zx2967_i2c *i2c = i2c_get_adapdata(adap);
438
439 if (size == I2C_SMBUS_QUICK)
440 read_write = I2C_SMBUS_WRITE;
441
442 switch (size) {
443 case I2C_SMBUS_QUICK:
444 case I2C_SMBUS_BYTE:
445 case I2C_SMBUS_BYTE_DATA:
446 case I2C_SMBUS_WORD_DATA:
447 zx2967_smbus_xfer_prepare(i2c, addr, read_write,
448 command, size, data);
449 break;
450 default:
451 return -EOPNOTSUPP;
452 }
453
454 if (read_write == I2C_SMBUS_READ)
455 return zx2967_smbus_xfer_read(i2c, size, data);
456
457 return zx2967_smbus_xfer_write(i2c);
458}
459
460static u32 zx2967_i2c_func(struct i2c_adapter *adap)
461{
462 return I2C_FUNC_I2C |
463 I2C_FUNC_SMBUS_QUICK |
464 I2C_FUNC_SMBUS_BYTE |
465 I2C_FUNC_SMBUS_BYTE_DATA |
466 I2C_FUNC_SMBUS_WORD_DATA |
467 I2C_FUNC_SMBUS_BLOCK_DATA |
468 I2C_FUNC_SMBUS_PROC_CALL |
469 I2C_FUNC_SMBUS_I2C_BLOCK;
470}
471
472static int __maybe_unused zx2967_i2c_suspend(struct device *dev)
473{
474 struct zx2967_i2c *i2c = dev_get_drvdata(dev);
475
476 i2c->is_suspended = true;
477 clk_disable_unprepare(i2c->clk);
478
479 return 0;
480}
481
482static int __maybe_unused zx2967_i2c_resume(struct device *dev)
483{
484 struct zx2967_i2c *i2c = dev_get_drvdata(dev);
485
486 i2c->is_suspended = false;
487 clk_prepare_enable(i2c->clk);
488
489 return 0;
490}
491
492static SIMPLE_DEV_PM_OPS(zx2967_i2c_dev_pm_ops,
493 zx2967_i2c_suspend, zx2967_i2c_resume);
494
495static const struct i2c_algorithm zx2967_i2c_algo = {
496 .master_xfer = zx2967_i2c_xfer,
497 .smbus_xfer = zx2967_smbus_xfer,
498 .functionality = zx2967_i2c_func,
499};
500
501static const struct of_device_id zx2967_i2c_of_match[] = {
502 { .compatible = "zte,zx296718-i2c", },
503 { },
504};
505MODULE_DEVICE_TABLE(of, zx2967_i2c_of_match);
506
507static int zx2967_i2c_probe(struct platform_device *pdev)
508{
509 struct zx2967_i2c *i2c;
510 void __iomem *reg_base;
511 struct resource *res;
512 struct clk *clk;
513 int ret;
514
515 i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
516 if (!i2c)
517 return -ENOMEM;
518
519 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
520 reg_base = devm_ioremap_resource(&pdev->dev, res);
521 if (IS_ERR(reg_base))
522 return PTR_ERR(reg_base);
523
524 clk = devm_clk_get(&pdev->dev, NULL);
525 if (IS_ERR(clk)) {
526 dev_err(&pdev->dev, "missing controller clock");
527 return PTR_ERR(clk);
528 }
529
530 ret = clk_prepare_enable(clk);
531 if (ret) {
532 dev_err(&pdev->dev, "failed to enable i2c_clk\n");
533 return ret;
534 }
535
536 ret = device_property_read_u32(&pdev->dev, "clock-frequency",
537 &i2c->clk_freq);
538 if (ret) {
539 dev_err(&pdev->dev, "missing clock-frequency");
540 return ret;
541 }
542
543 ret = platform_get_irq(pdev, 0);
544 if (ret < 0)
545 return ret;
546
547 i2c->irq = ret;
548 i2c->reg_base = reg_base;
549 i2c->clk = clk;
550
551 init_completion(&i2c->complete);
552 platform_set_drvdata(pdev, i2c);
553
554 ret = zx2967_i2c_reset_hardware(i2c);
555 if (ret) {
556 dev_err(&pdev->dev, "failed to initialize i2c controller\n");
557 goto err_clk_unprepare;
558 }
559
560 ret = devm_request_irq(&pdev->dev, i2c->irq,
561 zx2967_i2c_isr, 0, dev_name(&pdev->dev), i2c);
562 if (ret) {
563 dev_err(&pdev->dev, "failed to request irq %i\n", i2c->irq);
564 goto err_clk_unprepare;
565 }
566
567 i2c_set_adapdata(&i2c->adap, i2c);
568 strlcpy(i2c->adap.name, "zx2967 i2c adapter",
569 sizeof(i2c->adap.name));
570 i2c->adap.algo = &zx2967_i2c_algo;
571 i2c->adap.nr = pdev->id;
572 i2c->adap.dev.parent = &pdev->dev;
573 i2c->adap.dev.of_node = pdev->dev.of_node;
574
575 ret = i2c_add_numbered_adapter(&i2c->adap);
576 if (ret)
577 goto err_clk_unprepare;
578
579 return 0;
580
581err_clk_unprepare:
582 clk_disable_unprepare(i2c->clk);
583 return ret;
584}
585
586static int zx2967_i2c_remove(struct platform_device *pdev)
587{
588 struct zx2967_i2c *i2c = platform_get_drvdata(pdev);
589
590 i2c_del_adapter(&i2c->adap);
591 clk_disable_unprepare(i2c->clk);
592
593 return 0;
594}
595
596static struct platform_driver zx2967_i2c_driver = {
597 .probe = zx2967_i2c_probe,
598 .remove = zx2967_i2c_remove,
599 .driver = {
600 .name = "zx2967_i2c",
601 .of_match_table = zx2967_i2c_of_match,
602 .pm = &zx2967_i2c_dev_pm_ops,
603 },
604};
605module_platform_driver(zx2967_i2c_driver);
606
607MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>");
608MODULE_DESCRIPTION("ZTE ZX2967 I2C Bus Controller driver");
609MODULE_LICENSE("GPL v2");
610
