1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (c) 2014 Linaro Ltd.
4 * Copyright (c) 2014 HiSilicon Limited.
5 *
6 * Now only support 7 bit address.
7 */
8
9 #include <linux/clk.h>
10 #include <linux/delay.h>
11 #include <linux/i2c.h>
12 #include <linux/io.h>
13 #include <linux/interrupt.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/platform_device.h>
17 #include <linux/pm_runtime.h>
18
19 /* Register Map */
20 #define HIX5I2C_CTRL 0x00
21 #define HIX5I2C_COM 0x04
22 #define HIX5I2C_ICR 0x08
23 #define HIX5I2C_SR 0x0c
24 #define HIX5I2C_SCL_H 0x10
25 #define HIX5I2C_SCL_L 0x14
26 #define HIX5I2C_TXR 0x18
27 #define HIX5I2C_RXR 0x1c
28
29 /* I2C_CTRL_REG */
30 #define I2C_ENABLE BIT(8)
31 #define I2C_UNMASK_TOTAL BIT(7)
32 #define I2C_UNMASK_START BIT(6)
33 #define I2C_UNMASK_END BIT(5)
34 #define I2C_UNMASK_SEND BIT(4)
35 #define I2C_UNMASK_RECEIVE BIT(3)
36 #define I2C_UNMASK_ACK BIT(2)
37 #define I2C_UNMASK_ARBITRATE BIT(1)
38 #define I2C_UNMASK_OVER BIT(0)
39 #define I2C_UNMASK_ALL (I2C_UNMASK_ACK | I2C_UNMASK_OVER)
40
41 /* I2C_COM_REG */
42 #define I2C_NO_ACK BIT(4)
43 #define I2C_START BIT(3)
44 #define I2C_READ BIT(2)
45 #define I2C_WRITE BIT(1)
46 #define I2C_STOP BIT(0)
47
48 /* I2C_ICR_REG */
49 #define I2C_CLEAR_START BIT(6)
50 #define I2C_CLEAR_END BIT(5)
51 #define I2C_CLEAR_SEND BIT(4)
52 #define I2C_CLEAR_RECEIVE BIT(3)
53 #define I2C_CLEAR_ACK BIT(2)
54 #define I2C_CLEAR_ARBITRATE BIT(1)
55 #define I2C_CLEAR_OVER BIT(0)
56 #define I2C_CLEAR_ALL (I2C_CLEAR_START | I2C_CLEAR_END | \
57 I2C_CLEAR_SEND | I2C_CLEAR_RECEIVE | \
58 I2C_CLEAR_ACK | I2C_CLEAR_ARBITRATE | \
59 I2C_CLEAR_OVER)
60
61 /* I2C_SR_REG */
62 #define I2C_BUSY BIT(7)
63 #define I2C_START_INTR BIT(6)
64 #define I2C_END_INTR BIT(5)
65 #define I2C_SEND_INTR BIT(4)
66 #define I2C_RECEIVE_INTR BIT(3)
67 #define I2C_ACK_INTR BIT(2)
68 #define I2C_ARBITRATE_INTR BIT(1)
69 #define I2C_OVER_INTR BIT(0)
70
71 enum hix5hd2_i2c_state {
72 HIX5I2C_STAT_RW_ERR = -1,
73 HIX5I2C_STAT_INIT,
74 HIX5I2C_STAT_RW,
75 HIX5I2C_STAT_SND_STOP,
76 HIX5I2C_STAT_RW_SUCCESS,
77 };
78
79 struct hix5hd2_i2c_priv {
80 struct i2c_adapter adap;
81 struct i2c_msg *msg;
82 struct completion msg_complete;
83 unsigned int msg_idx;
84 unsigned int msg_len;
85 int stop;
86 void __iomem *regs;
87 struct clk *clk;
88 struct device *dev;
89 spinlock_t lock; /* IRQ synchronization */
90 int err;
91 unsigned int freq;
92 enum hix5hd2_i2c_state state;
93 };
94
hix5hd2_i2c_clr_pend_irq(struct hix5hd2_i2c_priv * priv)95 static u32 hix5hd2_i2c_clr_pend_irq(struct hix5hd2_i2c_priv *priv)
96 {
97 u32 val = readl_relaxed(priv->regs + HIX5I2C_SR);
98
99 writel_relaxed(val, priv->regs + HIX5I2C_ICR);
100
101 return val;
102 }
103
hix5hd2_i2c_clr_all_irq(struct hix5hd2_i2c_priv * priv)104 static void hix5hd2_i2c_clr_all_irq(struct hix5hd2_i2c_priv *priv)
105 {
106 writel_relaxed(I2C_CLEAR_ALL, priv->regs + HIX5I2C_ICR);
107 }
108
hix5hd2_i2c_disable_irq(struct hix5hd2_i2c_priv * priv)109 static void hix5hd2_i2c_disable_irq(struct hix5hd2_i2c_priv *priv)
110 {
111 writel_relaxed(0, priv->regs + HIX5I2C_CTRL);
112 }
113
hix5hd2_i2c_enable_irq(struct hix5hd2_i2c_priv * priv)114 static void hix5hd2_i2c_enable_irq(struct hix5hd2_i2c_priv *priv)
115 {
116 writel_relaxed(I2C_ENABLE | I2C_UNMASK_TOTAL | I2C_UNMASK_ALL,
117 priv->regs + HIX5I2C_CTRL);
118 }
119
hix5hd2_i2c_drv_setrate(struct hix5hd2_i2c_priv * priv)120 static void hix5hd2_i2c_drv_setrate(struct hix5hd2_i2c_priv *priv)
121 {
122 u32 rate, val;
123 u32 scl, sysclock;
124
125 /* close all i2c interrupt */
126 val = readl_relaxed(priv->regs + HIX5I2C_CTRL);
127 writel_relaxed(val & (~I2C_UNMASK_TOTAL), priv->regs + HIX5I2C_CTRL);
128
129 rate = priv->freq;
130 sysclock = clk_get_rate(priv->clk);
131 scl = (sysclock / (rate * 2)) / 2 - 1;
132 writel_relaxed(scl, priv->regs + HIX5I2C_SCL_H);
133 writel_relaxed(scl, priv->regs + HIX5I2C_SCL_L);
134
135 /* restore original interrupt*/
136 writel_relaxed(val, priv->regs + HIX5I2C_CTRL);
137
138 dev_dbg(priv->dev, "%s: sysclock=%d, rate=%d, scl=%d\n",
139 __func__, sysclock, rate, scl);
140 }
141
hix5hd2_i2c_init(struct hix5hd2_i2c_priv * priv)142 static void hix5hd2_i2c_init(struct hix5hd2_i2c_priv *priv)
143 {
144 hix5hd2_i2c_disable_irq(priv);
145 hix5hd2_i2c_drv_setrate(priv);
146 hix5hd2_i2c_clr_all_irq(priv);
147 hix5hd2_i2c_enable_irq(priv);
148 }
149
hix5hd2_i2c_reset(struct hix5hd2_i2c_priv * priv)150 static void hix5hd2_i2c_reset(struct hix5hd2_i2c_priv *priv)
151 {
152 clk_disable_unprepare(priv->clk);
153 msleep(20);
154 clk_prepare_enable(priv->clk);
155 hix5hd2_i2c_init(priv);
156 }
157
hix5hd2_i2c_wait_bus_idle(struct hix5hd2_i2c_priv * priv)158 static int hix5hd2_i2c_wait_bus_idle(struct hix5hd2_i2c_priv *priv)
159 {
160 unsigned long stop_time;
161 u32 int_status;
162
163 /* wait for 100 milli seconds for the bus to be idle */
164 stop_time = jiffies + msecs_to_jiffies(100);
165 do {
166 int_status = hix5hd2_i2c_clr_pend_irq(priv);
167 if (!(int_status & I2C_BUSY))
168 return 0;
169
170 usleep_range(50, 200);
171 } while (time_before(jiffies, stop_time));
172
173 return -EBUSY;
174 }
175
hix5hd2_rw_over(struct hix5hd2_i2c_priv * priv)176 static void hix5hd2_rw_over(struct hix5hd2_i2c_priv *priv)
177 {
178 if (priv->state == HIX5I2C_STAT_SND_STOP)
179 dev_dbg(priv->dev, "%s: rw and send stop over\n", __func__);
180 else
181 dev_dbg(priv->dev, "%s: have not data to send\n", __func__);
182
183 priv->state = HIX5I2C_STAT_RW_SUCCESS;
184 priv->err = 0;
185 }
186
hix5hd2_rw_handle_stop(struct hix5hd2_i2c_priv * priv)187 static void hix5hd2_rw_handle_stop(struct hix5hd2_i2c_priv *priv)
188 {
189 if (priv->stop) {
190 priv->state = HIX5I2C_STAT_SND_STOP;
191 writel_relaxed(I2C_STOP, priv->regs + HIX5I2C_COM);
192 } else {
193 hix5hd2_rw_over(priv);
194 }
195 }
196
hix5hd2_read_handle(struct hix5hd2_i2c_priv * priv)197 static void hix5hd2_read_handle(struct hix5hd2_i2c_priv *priv)
198 {
199 if (priv->msg_len == 1) {
200 /* the last byte don't need send ACK */
201 writel_relaxed(I2C_READ | I2C_NO_ACK, priv->regs + HIX5I2C_COM);
202 } else if (priv->msg_len > 1) {
203 /* if i2c controller receive data will send ACK */
204 writel_relaxed(I2C_READ, priv->regs + HIX5I2C_COM);
205 } else {
206 hix5hd2_rw_handle_stop(priv);
207 }
208 }
209
hix5hd2_write_handle(struct hix5hd2_i2c_priv * priv)210 static void hix5hd2_write_handle(struct hix5hd2_i2c_priv *priv)
211 {
212 u8 data;
213
214 if (priv->msg_len > 0) {
215 data = priv->msg->buf[priv->msg_idx++];
216 writel_relaxed(data, priv->regs + HIX5I2C_TXR);
217 writel_relaxed(I2C_WRITE, priv->regs + HIX5I2C_COM);
218 } else {
219 hix5hd2_rw_handle_stop(priv);
220 }
221 }
222
hix5hd2_rw_preprocess(struct hix5hd2_i2c_priv * priv)223 static int hix5hd2_rw_preprocess(struct hix5hd2_i2c_priv *priv)
224 {
225 u8 data;
226
227 if (priv->state == HIX5I2C_STAT_INIT) {
228 priv->state = HIX5I2C_STAT_RW;
229 } else if (priv->state == HIX5I2C_STAT_RW) {
230 if (priv->msg->flags & I2C_M_RD) {
231 data = readl_relaxed(priv->regs + HIX5I2C_RXR);
232 priv->msg->buf[priv->msg_idx++] = data;
233 }
234 priv->msg_len--;
235 } else {
236 dev_dbg(priv->dev, "%s: error: priv->state = %d, msg_len = %d\n",
237 __func__, priv->state, priv->msg_len);
238 return -EAGAIN;
239 }
240 return 0;
241 }
242
hix5hd2_i2c_irq(int irqno,void * dev_id)243 static irqreturn_t hix5hd2_i2c_irq(int irqno, void *dev_id)
244 {
245 struct hix5hd2_i2c_priv *priv = dev_id;
246 u32 int_status;
247 int ret;
248
249 spin_lock(&priv->lock);
250
251 int_status = hix5hd2_i2c_clr_pend_irq(priv);
252
253 /* handle error */
254 if (int_status & I2C_ARBITRATE_INTR) {
255 /* bus error */
256 dev_dbg(priv->dev, "ARB bus loss\n");
257 priv->err = -EAGAIN;
258 priv->state = HIX5I2C_STAT_RW_ERR;
259 goto stop;
260 } else if (int_status & I2C_ACK_INTR) {
261 /* ack error */
262 dev_dbg(priv->dev, "No ACK from device\n");
263 priv->err = -ENXIO;
264 priv->state = HIX5I2C_STAT_RW_ERR;
265 goto stop;
266 }
267
268 if (int_status & I2C_OVER_INTR) {
269 if (priv->msg_len > 0) {
270 ret = hix5hd2_rw_preprocess(priv);
271 if (ret) {
272 priv->err = ret;
273 priv->state = HIX5I2C_STAT_RW_ERR;
274 goto stop;
275 }
276 if (priv->msg->flags & I2C_M_RD)
277 hix5hd2_read_handle(priv);
278 else
279 hix5hd2_write_handle(priv);
280 } else {
281 hix5hd2_rw_over(priv);
282 }
283 }
284
285 stop:
286 if ((priv->state == HIX5I2C_STAT_RW_SUCCESS &&
287 priv->msg->len == priv->msg_idx) ||
288 (priv->state == HIX5I2C_STAT_RW_ERR)) {
289 hix5hd2_i2c_disable_irq(priv);
290 hix5hd2_i2c_clr_pend_irq(priv);
291 complete(&priv->msg_complete);
292 }
293
294 spin_unlock(&priv->lock);
295
296 return IRQ_HANDLED;
297 }
298
hix5hd2_i2c_message_start(struct hix5hd2_i2c_priv * priv,int stop)299 static void hix5hd2_i2c_message_start(struct hix5hd2_i2c_priv *priv, int stop)
300 {
301 unsigned long flags;
302
303 spin_lock_irqsave(&priv->lock, flags);
304 hix5hd2_i2c_clr_all_irq(priv);
305 hix5hd2_i2c_enable_irq(priv);
306
307 writel_relaxed(i2c_8bit_addr_from_msg(priv->msg),
308 priv->regs + HIX5I2C_TXR);
309
310 writel_relaxed(I2C_WRITE | I2C_START, priv->regs + HIX5I2C_COM);
311 spin_unlock_irqrestore(&priv->lock, flags);
312 }
313
hix5hd2_i2c_xfer_msg(struct hix5hd2_i2c_priv * priv,struct i2c_msg * msgs,int stop)314 static int hix5hd2_i2c_xfer_msg(struct hix5hd2_i2c_priv *priv,
315 struct i2c_msg *msgs, int stop)
316 {
317 unsigned long time_left;
318 int ret;
319
320 priv->msg = msgs;
321 priv->msg_idx = 0;
322 priv->msg_len = priv->msg->len;
323 priv->stop = stop;
324 priv->err = 0;
325 priv->state = HIX5I2C_STAT_INIT;
326
327 reinit_completion(&priv->msg_complete);
328 hix5hd2_i2c_message_start(priv, stop);
329
330 time_left = wait_for_completion_timeout(&priv->msg_complete,
331 priv->adap.timeout);
332 if (time_left == 0) {
333 priv->state = HIX5I2C_STAT_RW_ERR;
334 priv->err = -ETIMEDOUT;
335 dev_warn(priv->dev, "%s timeout=%d\n",
336 msgs->flags & I2C_M_RD ? "rx" : "tx",
337 priv->adap.timeout);
338 }
339 ret = priv->state;
340
341 /*
342 * If this is the last message to be transfered (stop == 1)
343 * Then check if the bus can be brought back to idle.
344 */
345 if (priv->state == HIX5I2C_STAT_RW_SUCCESS && stop)
346 ret = hix5hd2_i2c_wait_bus_idle(priv);
347
348 if (ret < 0)
349 hix5hd2_i2c_reset(priv);
350
351 return priv->err;
352 }
353
hix5hd2_i2c_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)354 static int hix5hd2_i2c_xfer(struct i2c_adapter *adap,
355 struct i2c_msg *msgs, int num)
356 {
357 struct hix5hd2_i2c_priv *priv = i2c_get_adapdata(adap);
358 int i, ret, stop;
359
360 pm_runtime_get_sync(priv->dev);
361
362 for (i = 0; i < num; i++, msgs++) {
363 if ((i == num - 1) || (msgs->flags & I2C_M_STOP))
364 stop = 1;
365 else
366 stop = 0;
367
368 ret = hix5hd2_i2c_xfer_msg(priv, msgs, stop);
369 if (ret < 0)
370 goto out;
371 }
372
373 ret = num;
374
375 out:
376 pm_runtime_mark_last_busy(priv->dev);
377 pm_runtime_put_autosuspend(priv->dev);
378 return ret;
379 }
380
hix5hd2_i2c_func(struct i2c_adapter * adap)381 static u32 hix5hd2_i2c_func(struct i2c_adapter *adap)
382 {
383 return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
384 }
385
386 static const struct i2c_algorithm hix5hd2_i2c_algorithm = {
387 .xfer = hix5hd2_i2c_xfer,
388 .functionality = hix5hd2_i2c_func,
389 };
390
hix5hd2_i2c_probe(struct platform_device * pdev)391 static int hix5hd2_i2c_probe(struct platform_device *pdev)
392 {
393 struct device_node *np = pdev->dev.of_node;
394 struct hix5hd2_i2c_priv *priv;
395 unsigned int freq;
396 int irq, ret;
397
398 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
399 if (!priv)
400 return -ENOMEM;
401
402 if (of_property_read_u32(np, "clock-frequency", &freq)) {
403 /* use 100k as default value */
404 priv->freq = I2C_MAX_STANDARD_MODE_FREQ;
405 } else {
406 if (freq > I2C_MAX_FAST_MODE_FREQ) {
407 priv->freq = I2C_MAX_FAST_MODE_FREQ;
408 dev_warn(priv->dev, "use max freq %d instead\n",
409 I2C_MAX_FAST_MODE_FREQ);
410 } else {
411 priv->freq = freq;
412 }
413 }
414
415 priv->regs = devm_platform_ioremap_resource(pdev, 0);
416 if (IS_ERR(priv->regs))
417 return PTR_ERR(priv->regs);
418
419 irq = platform_get_irq(pdev, 0);
420 if (irq < 0)
421 return irq;
422
423 priv->clk = devm_clk_get_enabled(&pdev->dev, NULL);
424 if (IS_ERR(priv->clk)) {
425 dev_err(&pdev->dev, "cannot enable clock\n");
426 return PTR_ERR(priv->clk);
427 }
428
429 strscpy(priv->adap.name, "hix5hd2-i2c", sizeof(priv->adap.name));
430 priv->dev = &pdev->dev;
431 priv->adap.owner = THIS_MODULE;
432 priv->adap.algo = &hix5hd2_i2c_algorithm;
433 priv->adap.retries = 3;
434 priv->adap.dev.of_node = np;
435 priv->adap.algo_data = priv;
436 priv->adap.dev.parent = &pdev->dev;
437 i2c_set_adapdata(&priv->adap, priv);
438 platform_set_drvdata(pdev, priv);
439 spin_lock_init(&priv->lock);
440 init_completion(&priv->msg_complete);
441
442 hix5hd2_i2c_init(priv);
443
444 ret = devm_request_irq(&pdev->dev, irq, hix5hd2_i2c_irq,
445 IRQF_NO_SUSPEND, dev_name(&pdev->dev), priv);
446 if (ret != 0) {
447 dev_err(&pdev->dev, "cannot request HS-I2C IRQ %d\n", irq);
448 return ret;
449 }
450
451 pm_runtime_set_autosuspend_delay(priv->dev, MSEC_PER_SEC);
452 pm_runtime_use_autosuspend(priv->dev);
453 pm_runtime_set_active(priv->dev);
454 pm_runtime_enable(priv->dev);
455
456 ret = i2c_add_adapter(&priv->adap);
457 if (ret < 0)
458 goto err_runtime;
459
460 return ret;
461
462 err_runtime:
463 pm_runtime_disable(priv->dev);
464 pm_runtime_set_suspended(priv->dev);
465
466 return ret;
467 }
468
hix5hd2_i2c_remove(struct platform_device * pdev)469 static void hix5hd2_i2c_remove(struct platform_device *pdev)
470 {
471 struct hix5hd2_i2c_priv *priv = platform_get_drvdata(pdev);
472
473 i2c_del_adapter(&priv->adap);
474 pm_runtime_disable(priv->dev);
475 pm_runtime_set_suspended(priv->dev);
476 }
477
hix5hd2_i2c_runtime_suspend(struct device * dev)478 static int hix5hd2_i2c_runtime_suspend(struct device *dev)
479 {
480 struct hix5hd2_i2c_priv *priv = dev_get_drvdata(dev);
481
482 clk_disable_unprepare(priv->clk);
483
484 return 0;
485 }
486
hix5hd2_i2c_runtime_resume(struct device * dev)487 static int hix5hd2_i2c_runtime_resume(struct device *dev)
488 {
489 struct hix5hd2_i2c_priv *priv = dev_get_drvdata(dev);
490
491 clk_prepare_enable(priv->clk);
492 hix5hd2_i2c_init(priv);
493
494 return 0;
495 }
496
497 static const struct dev_pm_ops hix5hd2_i2c_pm_ops = {
498 RUNTIME_PM_OPS(hix5hd2_i2c_runtime_suspend,
499 hix5hd2_i2c_runtime_resume,
500 NULL)
501 };
502
503 static const struct of_device_id hix5hd2_i2c_match[] = {
504 { .compatible = "hisilicon,hix5hd2-i2c" },
505 {},
506 };
507 MODULE_DEVICE_TABLE(of, hix5hd2_i2c_match);
508
509 static struct platform_driver hix5hd2_i2c_driver = {
510 .probe = hix5hd2_i2c_probe,
511 .remove_new = hix5hd2_i2c_remove,
512 .driver = {
513 .name = "hix5hd2-i2c",
514 .pm = pm_ptr(&hix5hd2_i2c_pm_ops),
515 .of_match_table = hix5hd2_i2c_match,
516 },
517 };
518
519 module_platform_driver(hix5hd2_i2c_driver);
520
521 MODULE_DESCRIPTION("Hix5hd2 I2C Bus driver");
522 MODULE_AUTHOR("Wei Yan <sledge.yanwei@huawei.com>");
523 MODULE_LICENSE("GPL");
524 MODULE_ALIAS("platform:hix5hd2-i2c");
525