1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2017 Sanechips Technology Co., Ltd.
4 * Copyright 2017 Linaro Ltd.
5 *
6 * Author: Baoyou Xie <baoyou.xie@linaro.org>
7 */
8
9 #include <linux/clk.h>
10 #include <linux/i2c.h>
11 #include <linux/interrupt.h>
12 #include <linux/io.h>
13 #include <linux/module.h>
14 #include <linux/platform_device.h>
15
16 #define REG_CMD 0x04
17 #define REG_DEVADDR_H 0x0C
18 #define REG_DEVADDR_L 0x10
19 #define REG_CLK_DIV_FS 0x14
20 #define REG_CLK_DIV_HS 0x18
21 #define REG_WRCONF 0x1C
22 #define REG_RDCONF 0x20
23 #define REG_DATA 0x24
24 #define REG_STAT 0x28
25
26 #define I2C_STOP 0
27 #define I2C_MASTER BIT(0)
28 #define I2C_ADDR_MODE_TEN BIT(1)
29 #define I2C_IRQ_MSK_ENABLE BIT(3)
30 #define I2C_RW_READ BIT(4)
31 #define I2C_CMB_RW_EN BIT(5)
32 #define I2C_START BIT(6)
33
34 #define I2C_ADDR_LOW_MASK GENMASK(6, 0)
35 #define I2C_ADDR_LOW_SHIFT 0
36 #define I2C_ADDR_HI_MASK GENMASK(2, 0)
37 #define I2C_ADDR_HI_SHIFT 7
38
39 #define I2C_WFIFO_RESET BIT(7)
40 #define I2C_RFIFO_RESET BIT(7)
41
42 #define I2C_IRQ_ACK_CLEAR BIT(7)
43 #define I2C_INT_MASK GENMASK(6, 0)
44
45 #define I2C_TRANS_DONE BIT(0)
46 #define I2C_SR_EDEVICE BIT(1)
47 #define I2C_SR_EDATA BIT(2)
48
49 #define I2C_FIFO_MAX 16
50
51 #define I2C_TIMEOUT msecs_to_jiffies(1000)
52
53 #define DEV(i2c) ((i2c)->adap.dev.parent)
54
55 struct zx2967_i2c {
56 struct i2c_adapter adap;
57 struct clk *clk;
58 struct completion complete;
59 u32 clk_freq;
60 void __iomem *reg_base;
61 size_t residue;
62 int irq;
63 int msg_rd;
64 u8 *cur_trans;
65 u8 access_cnt;
66 int error;
67 };
68
zx2967_i2c_writel(struct zx2967_i2c * i2c,u32 val,unsigned long reg)69 static void zx2967_i2c_writel(struct zx2967_i2c *i2c,
70 u32 val, unsigned long reg)
71 {
72 writel_relaxed(val, i2c->reg_base + reg);
73 }
74
zx2967_i2c_readl(struct zx2967_i2c * i2c,unsigned long reg)75 static u32 zx2967_i2c_readl(struct zx2967_i2c *i2c, unsigned long reg)
76 {
77 return readl_relaxed(i2c->reg_base + reg);
78 }
79
zx2967_i2c_writesb(struct zx2967_i2c * i2c,void * data,unsigned long reg,int len)80 static void zx2967_i2c_writesb(struct zx2967_i2c *i2c,
81 void *data, unsigned long reg, int len)
82 {
83 writesb(i2c->reg_base + reg, data, len);
84 }
85
zx2967_i2c_readsb(struct zx2967_i2c * i2c,void * data,unsigned long reg,int len)86 static void zx2967_i2c_readsb(struct zx2967_i2c *i2c,
87 void *data, unsigned long reg, int len)
88 {
89 readsb(i2c->reg_base + reg, data, len);
90 }
91
zx2967_i2c_start_ctrl(struct zx2967_i2c * i2c)92 static void zx2967_i2c_start_ctrl(struct zx2967_i2c *i2c)
93 {
94 u32 status;
95 u32 ctl;
96
97 status = zx2967_i2c_readl(i2c, REG_STAT);
98 status |= I2C_IRQ_ACK_CLEAR;
99 zx2967_i2c_writel(i2c, status, REG_STAT);
100
101 ctl = zx2967_i2c_readl(i2c, REG_CMD);
102 if (i2c->msg_rd)
103 ctl |= I2C_RW_READ;
104 else
105 ctl &= ~I2C_RW_READ;
106 ctl &= ~I2C_CMB_RW_EN;
107 ctl |= I2C_START;
108 zx2967_i2c_writel(i2c, ctl, REG_CMD);
109 }
110
zx2967_i2c_flush_fifos(struct zx2967_i2c * i2c)111 static void zx2967_i2c_flush_fifos(struct zx2967_i2c *i2c)
112 {
113 u32 offset;
114 u32 val;
115
116 if (i2c->msg_rd) {
117 offset = REG_RDCONF;
118 val = I2C_RFIFO_RESET;
119 } else {
120 offset = REG_WRCONF;
121 val = I2C_WFIFO_RESET;
122 }
123
124 val |= zx2967_i2c_readl(i2c, offset);
125 zx2967_i2c_writel(i2c, val, offset);
126 }
127
zx2967_i2c_empty_rx_fifo(struct zx2967_i2c * i2c,u32 size)128 static int zx2967_i2c_empty_rx_fifo(struct zx2967_i2c *i2c, u32 size)
129 {
130 u8 val[I2C_FIFO_MAX] = {0};
131 int i;
132
133 if (size > I2C_FIFO_MAX) {
134 dev_err(DEV(i2c), "fifo size %d over the max value %d\n",
135 size, I2C_FIFO_MAX);
136 return -EINVAL;
137 }
138
139 zx2967_i2c_readsb(i2c, val, REG_DATA, size);
140 for (i = 0; i < size; i++) {
141 *i2c->cur_trans++ = val[i];
142 i2c->residue--;
143 }
144
145 barrier();
146
147 return 0;
148 }
149
zx2967_i2c_fill_tx_fifo(struct zx2967_i2c * i2c)150 static int zx2967_i2c_fill_tx_fifo(struct zx2967_i2c *i2c)
151 {
152 size_t residue = i2c->residue;
153 u8 *buf = i2c->cur_trans;
154
155 if (residue == 0) {
156 dev_err(DEV(i2c), "residue is %d\n", (int)residue);
157 return -EINVAL;
158 }
159
160 if (residue <= I2C_FIFO_MAX) {
161 zx2967_i2c_writesb(i2c, buf, REG_DATA, residue);
162
163 /* Again update before writing to FIFO to make sure isr sees. */
164 i2c->residue = 0;
165 i2c->cur_trans = NULL;
166 } else {
167 zx2967_i2c_writesb(i2c, buf, REG_DATA, I2C_FIFO_MAX);
168 i2c->residue -= I2C_FIFO_MAX;
169 i2c->cur_trans += I2C_FIFO_MAX;
170 }
171
172 barrier();
173
174 return 0;
175 }
176
zx2967_i2c_reset_hardware(struct zx2967_i2c * i2c)177 static int zx2967_i2c_reset_hardware(struct zx2967_i2c *i2c)
178 {
179 u32 val;
180 u32 clk_div;
181
182 val = I2C_MASTER | I2C_IRQ_MSK_ENABLE;
183 zx2967_i2c_writel(i2c, val, REG_CMD);
184
185 clk_div = clk_get_rate(i2c->clk) / i2c->clk_freq - 1;
186 zx2967_i2c_writel(i2c, clk_div, REG_CLK_DIV_FS);
187 zx2967_i2c_writel(i2c, clk_div, REG_CLK_DIV_HS);
188
189 zx2967_i2c_writel(i2c, I2C_FIFO_MAX - 1, REG_WRCONF);
190 zx2967_i2c_writel(i2c, I2C_FIFO_MAX - 1, REG_RDCONF);
191 zx2967_i2c_writel(i2c, 1, REG_RDCONF);
192
193 zx2967_i2c_flush_fifos(i2c);
194
195 return 0;
196 }
197
zx2967_i2c_isr_clr(struct zx2967_i2c * i2c)198 static void zx2967_i2c_isr_clr(struct zx2967_i2c *i2c)
199 {
200 u32 status;
201
202 status = zx2967_i2c_readl(i2c, REG_STAT);
203 status |= I2C_IRQ_ACK_CLEAR;
204 zx2967_i2c_writel(i2c, status, REG_STAT);
205 }
206
zx2967_i2c_isr(int irq,void * dev_id)207 static irqreturn_t zx2967_i2c_isr(int irq, void *dev_id)
208 {
209 u32 status;
210 struct zx2967_i2c *i2c = (struct zx2967_i2c *)dev_id;
211
212 status = zx2967_i2c_readl(i2c, REG_STAT) & I2C_INT_MASK;
213 zx2967_i2c_isr_clr(i2c);
214
215 if (status & I2C_SR_EDEVICE)
216 i2c->error = -ENXIO;
217 else if (status & I2C_SR_EDATA)
218 i2c->error = -EIO;
219 else if (status & I2C_TRANS_DONE)
220 i2c->error = 0;
221 else
222 goto done;
223
224 complete(&i2c->complete);
225 done:
226 return IRQ_HANDLED;
227 }
228
zx2967_set_addr(struct zx2967_i2c * i2c,u16 addr)229 static void zx2967_set_addr(struct zx2967_i2c *i2c, u16 addr)
230 {
231 u16 val;
232
233 val = (addr >> I2C_ADDR_LOW_SHIFT) & I2C_ADDR_LOW_MASK;
234 zx2967_i2c_writel(i2c, val, REG_DEVADDR_L);
235
236 val = (addr >> I2C_ADDR_HI_SHIFT) & I2C_ADDR_HI_MASK;
237 zx2967_i2c_writel(i2c, val, REG_DEVADDR_H);
238 if (val)
239 val = zx2967_i2c_readl(i2c, REG_CMD) | I2C_ADDR_MODE_TEN;
240 else
241 val = zx2967_i2c_readl(i2c, REG_CMD) & ~I2C_ADDR_MODE_TEN;
242 zx2967_i2c_writel(i2c, val, REG_CMD);
243 }
244
zx2967_i2c_xfer_bytes(struct zx2967_i2c * i2c,u32 bytes)245 static int zx2967_i2c_xfer_bytes(struct zx2967_i2c *i2c, u32 bytes)
246 {
247 unsigned long time_left;
248 int rd = i2c->msg_rd;
249 int ret;
250
251 reinit_completion(&i2c->complete);
252
253 if (rd) {
254 zx2967_i2c_writel(i2c, bytes - 1, REG_RDCONF);
255 } else {
256 ret = zx2967_i2c_fill_tx_fifo(i2c);
257 if (ret)
258 return ret;
259 }
260
261 zx2967_i2c_start_ctrl(i2c);
262
263 time_left = wait_for_completion_timeout(&i2c->complete,
264 I2C_TIMEOUT);
265 if (time_left == 0)
266 return -ETIMEDOUT;
267
268 if (i2c->error)
269 return i2c->error;
270
271 return rd ? zx2967_i2c_empty_rx_fifo(i2c, bytes) : 0;
272 }
273
zx2967_i2c_xfer_msg(struct zx2967_i2c * i2c,struct i2c_msg * msg)274 static int zx2967_i2c_xfer_msg(struct zx2967_i2c *i2c,
275 struct i2c_msg *msg)
276 {
277 int ret;
278 int i;
279
280 zx2967_i2c_flush_fifos(i2c);
281
282 i2c->cur_trans = msg->buf;
283 i2c->residue = msg->len;
284 i2c->access_cnt = msg->len / I2C_FIFO_MAX;
285 i2c->msg_rd = msg->flags & I2C_M_RD;
286
287 for (i = 0; i < i2c->access_cnt; i++) {
288 ret = zx2967_i2c_xfer_bytes(i2c, I2C_FIFO_MAX);
289 if (ret)
290 return ret;
291 }
292
293 if (i2c->residue > 0) {
294 ret = zx2967_i2c_xfer_bytes(i2c, i2c->residue);
295 if (ret)
296 return ret;
297 }
298
299 i2c->residue = 0;
300 i2c->access_cnt = 0;
301
302 return 0;
303 }
304
zx2967_i2c_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)305 static int zx2967_i2c_xfer(struct i2c_adapter *adap,
306 struct i2c_msg *msgs, int num)
307 {
308 struct zx2967_i2c *i2c = i2c_get_adapdata(adap);
309 int ret;
310 int i;
311
312 zx2967_set_addr(i2c, msgs->addr);
313
314 for (i = 0; i < num; i++) {
315 ret = zx2967_i2c_xfer_msg(i2c, &msgs[i]);
316 if (ret)
317 return ret;
318 }
319
320 return num;
321 }
322
323 static void
zx2967_smbus_xfer_prepare(struct zx2967_i2c * i2c,u16 addr,char read_write,u8 command,int size,union i2c_smbus_data * data)324 zx2967_smbus_xfer_prepare(struct zx2967_i2c *i2c, u16 addr,
325 char read_write, u8 command, int size,
326 union i2c_smbus_data *data)
327 {
328 u32 val;
329
330 val = zx2967_i2c_readl(i2c, REG_RDCONF);
331 val |= I2C_RFIFO_RESET;
332 zx2967_i2c_writel(i2c, val, REG_RDCONF);
333 zx2967_set_addr(i2c, addr);
334 val = zx2967_i2c_readl(i2c, REG_CMD);
335 val &= ~I2C_RW_READ;
336 zx2967_i2c_writel(i2c, val, REG_CMD);
337
338 switch (size) {
339 case I2C_SMBUS_BYTE:
340 zx2967_i2c_writel(i2c, command, REG_DATA);
341 break;
342 case I2C_SMBUS_BYTE_DATA:
343 zx2967_i2c_writel(i2c, command, REG_DATA);
344 if (read_write == I2C_SMBUS_WRITE)
345 zx2967_i2c_writel(i2c, data->byte, REG_DATA);
346 break;
347 case I2C_SMBUS_WORD_DATA:
348 zx2967_i2c_writel(i2c, command, REG_DATA);
349 if (read_write == I2C_SMBUS_WRITE) {
350 zx2967_i2c_writel(i2c, (data->word >> 8), REG_DATA);
351 zx2967_i2c_writel(i2c, (data->word & 0xff),
352 REG_DATA);
353 }
354 break;
355 }
356 }
357
zx2967_smbus_xfer_read(struct zx2967_i2c * i2c,int size,union i2c_smbus_data * data)358 static int zx2967_smbus_xfer_read(struct zx2967_i2c *i2c, int size,
359 union i2c_smbus_data *data)
360 {
361 unsigned long time_left;
362 u8 buf[2];
363 u32 val;
364
365 reinit_completion(&i2c->complete);
366
367 val = zx2967_i2c_readl(i2c, REG_CMD);
368 val |= I2C_CMB_RW_EN;
369 zx2967_i2c_writel(i2c, val, REG_CMD);
370
371 val = zx2967_i2c_readl(i2c, REG_CMD);
372 val |= I2C_START;
373 zx2967_i2c_writel(i2c, val, REG_CMD);
374
375 time_left = wait_for_completion_timeout(&i2c->complete,
376 I2C_TIMEOUT);
377 if (time_left == 0)
378 return -ETIMEDOUT;
379
380 if (i2c->error)
381 return i2c->error;
382
383 switch (size) {
384 case I2C_SMBUS_BYTE:
385 case I2C_SMBUS_BYTE_DATA:
386 val = zx2967_i2c_readl(i2c, REG_DATA);
387 data->byte = val;
388 break;
389 case I2C_SMBUS_WORD_DATA:
390 case I2C_SMBUS_PROC_CALL:
391 buf[0] = zx2967_i2c_readl(i2c, REG_DATA);
392 buf[1] = zx2967_i2c_readl(i2c, REG_DATA);
393 data->word = (buf[0] << 8) | buf[1];
394 break;
395 default:
396 return -EOPNOTSUPP;
397 }
398
399 return 0;
400 }
401
zx2967_smbus_xfer_write(struct zx2967_i2c * i2c)402 static int zx2967_smbus_xfer_write(struct zx2967_i2c *i2c)
403 {
404 unsigned long time_left;
405 u32 val;
406
407 reinit_completion(&i2c->complete);
408 val = zx2967_i2c_readl(i2c, REG_CMD);
409 val |= I2C_START;
410 zx2967_i2c_writel(i2c, val, REG_CMD);
411
412 time_left = wait_for_completion_timeout(&i2c->complete,
413 I2C_TIMEOUT);
414 if (time_left == 0)
415 return -ETIMEDOUT;
416
417 if (i2c->error)
418 return i2c->error;
419
420 return 0;
421 }
422
zx2967_smbus_xfer(struct i2c_adapter * adap,u16 addr,unsigned short flags,char read_write,u8 command,int size,union i2c_smbus_data * data)423 static int zx2967_smbus_xfer(struct i2c_adapter *adap, u16 addr,
424 unsigned short flags, char read_write,
425 u8 command, int size, union i2c_smbus_data *data)
426 {
427 struct zx2967_i2c *i2c = i2c_get_adapdata(adap);
428
429 if (size == I2C_SMBUS_QUICK)
430 read_write = I2C_SMBUS_WRITE;
431
432 switch (size) {
433 case I2C_SMBUS_QUICK:
434 case I2C_SMBUS_BYTE:
435 case I2C_SMBUS_BYTE_DATA:
436 case I2C_SMBUS_WORD_DATA:
437 zx2967_smbus_xfer_prepare(i2c, addr, read_write,
438 command, size, data);
439 break;
440 default:
441 return -EOPNOTSUPP;
442 }
443
444 if (read_write == I2C_SMBUS_READ)
445 return zx2967_smbus_xfer_read(i2c, size, data);
446
447 return zx2967_smbus_xfer_write(i2c);
448 }
449
zx2967_i2c_func(struct i2c_adapter * adap)450 static u32 zx2967_i2c_func(struct i2c_adapter *adap)
451 {
452 return I2C_FUNC_I2C |
453 I2C_FUNC_SMBUS_QUICK |
454 I2C_FUNC_SMBUS_BYTE |
455 I2C_FUNC_SMBUS_BYTE_DATA |
456 I2C_FUNC_SMBUS_WORD_DATA |
457 I2C_FUNC_SMBUS_BLOCK_DATA |
458 I2C_FUNC_SMBUS_PROC_CALL |
459 I2C_FUNC_SMBUS_I2C_BLOCK;
460 }
461
zx2967_i2c_suspend(struct device * dev)462 static int __maybe_unused zx2967_i2c_suspend(struct device *dev)
463 {
464 struct zx2967_i2c *i2c = dev_get_drvdata(dev);
465
466 i2c_mark_adapter_suspended(&i2c->adap);
467 clk_disable_unprepare(i2c->clk);
468
469 return 0;
470 }
471
zx2967_i2c_resume(struct device * dev)472 static int __maybe_unused zx2967_i2c_resume(struct device *dev)
473 {
474 struct zx2967_i2c *i2c = dev_get_drvdata(dev);
475
476 clk_prepare_enable(i2c->clk);
477 i2c_mark_adapter_resumed(&i2c->adap);
478
479 return 0;
480 }
481
482 static SIMPLE_DEV_PM_OPS(zx2967_i2c_dev_pm_ops,
483 zx2967_i2c_suspend, zx2967_i2c_resume);
484
485 static const struct i2c_algorithm zx2967_i2c_algo = {
486 .master_xfer = zx2967_i2c_xfer,
487 .smbus_xfer = zx2967_smbus_xfer,
488 .functionality = zx2967_i2c_func,
489 };
490
491 static const struct i2c_adapter_quirks zx2967_i2c_quirks = {
492 .flags = I2C_AQ_NO_ZERO_LEN,
493 };
494
495 static const struct of_device_id zx2967_i2c_of_match[] = {
496 { .compatible = "zte,zx296718-i2c", },
497 { },
498 };
499 MODULE_DEVICE_TABLE(of, zx2967_i2c_of_match);
500
zx2967_i2c_probe(struct platform_device * pdev)501 static int zx2967_i2c_probe(struct platform_device *pdev)
502 {
503 struct zx2967_i2c *i2c;
504 void __iomem *reg_base;
505 struct resource *res;
506 struct clk *clk;
507 int ret;
508
509 i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
510 if (!i2c)
511 return -ENOMEM;
512
513 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
514 reg_base = devm_ioremap_resource(&pdev->dev, res);
515 if (IS_ERR(reg_base))
516 return PTR_ERR(reg_base);
517
518 clk = devm_clk_get(&pdev->dev, NULL);
519 if (IS_ERR(clk)) {
520 dev_err(&pdev->dev, "missing controller clock");
521 return PTR_ERR(clk);
522 }
523
524 ret = clk_prepare_enable(clk);
525 if (ret) {
526 dev_err(&pdev->dev, "failed to enable i2c_clk\n");
527 return ret;
528 }
529
530 ret = device_property_read_u32(&pdev->dev, "clock-frequency",
531 &i2c->clk_freq);
532 if (ret) {
533 dev_err(&pdev->dev, "missing clock-frequency");
534 return ret;
535 }
536
537 ret = platform_get_irq(pdev, 0);
538 if (ret < 0)
539 return ret;
540
541 i2c->irq = ret;
542 i2c->reg_base = reg_base;
543 i2c->clk = clk;
544
545 init_completion(&i2c->complete);
546 platform_set_drvdata(pdev, i2c);
547
548 ret = zx2967_i2c_reset_hardware(i2c);
549 if (ret) {
550 dev_err(&pdev->dev, "failed to initialize i2c controller\n");
551 goto err_clk_unprepare;
552 }
553
554 ret = devm_request_irq(&pdev->dev, i2c->irq,
555 zx2967_i2c_isr, 0, dev_name(&pdev->dev), i2c);
556 if (ret) {
557 dev_err(&pdev->dev, "failed to request irq %i\n", i2c->irq);
558 goto err_clk_unprepare;
559 }
560
561 i2c_set_adapdata(&i2c->adap, i2c);
562 strlcpy(i2c->adap.name, "zx2967 i2c adapter",
563 sizeof(i2c->adap.name));
564 i2c->adap.algo = &zx2967_i2c_algo;
565 i2c->adap.quirks = &zx2967_i2c_quirks;
566 i2c->adap.nr = pdev->id;
567 i2c->adap.dev.parent = &pdev->dev;
568 i2c->adap.dev.of_node = pdev->dev.of_node;
569
570 ret = i2c_add_numbered_adapter(&i2c->adap);
571 if (ret)
572 goto err_clk_unprepare;
573
574 return 0;
575
576 err_clk_unprepare:
577 clk_disable_unprepare(i2c->clk);
578 return ret;
579 }
580
zx2967_i2c_remove(struct platform_device * pdev)581 static int zx2967_i2c_remove(struct platform_device *pdev)
582 {
583 struct zx2967_i2c *i2c = platform_get_drvdata(pdev);
584
585 i2c_del_adapter(&i2c->adap);
586 clk_disable_unprepare(i2c->clk);
587
588 return 0;
589 }
590
591 static struct platform_driver zx2967_i2c_driver = {
592 .probe = zx2967_i2c_probe,
593 .remove = zx2967_i2c_remove,
594 .driver = {
595 .name = "zx2967_i2c",
596 .of_match_table = zx2967_i2c_of_match,
597 .pm = &zx2967_i2c_dev_pm_ops,
598 },
599 };
600 module_platform_driver(zx2967_i2c_driver);
601
602 MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>");
603 MODULE_DESCRIPTION("ZTE ZX2967 I2C Bus Controller driver");
604 MODULE_LICENSE("GPL v2");
605
