1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Driver for the Renesas RZ/V2M I2C unit
4 *
5 * Copyright (C) 2016-2022 Renesas Electronics Corporation
6 */
7
8 #include <linux/bits.h>
9 #include <linux/clk.h>
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/interrupt.h>
13 #include <linux/io.h>
14 #include <linux/iopoll.h>
15 #include <linux/i2c.h>
16 #include <linux/jiffies.h>
17 #include <linux/kernel.h>
18 #include <linux/math64.h>
19 #include <linux/module.h>
20 #include <linux/mod_devicetable.h>
21 #include <linux/platform_device.h>
22 #include <linux/pm_runtime.h>
23 #include <linux/reset.h>
24
25 /* Register offsets */
26 #define IICB0DAT 0x00 /* Data Register */
27 #define IICB0CTL0 0x08 /* Control Register 0 */
28 #define IICB0TRG 0x0C /* Trigger Register */
29 #define IICB0STR0 0x10 /* Status Register 0 */
30 #define IICB0CTL1 0x20 /* Control Register 1 */
31 #define IICB0WL 0x24 /* Low Level Width Setting Reg */
32 #define IICB0WH 0x28 /* How Level Width Setting Reg */
33
34 /* IICB0CTL0 */
35 #define IICB0IICE BIT(7) /* I2C Enable */
36 #define IICB0SLWT BIT(1) /* Interrupt Request Timing */
37 #define IICB0SLAC BIT(0) /* Acknowledge */
38
39 /* IICB0TRG */
40 #define IICB0WRET BIT(2) /* Quit Wait Trigger */
41 #define IICB0STT BIT(1) /* Create Start Condition Trigger */
42 #define IICB0SPT BIT(0) /* Create Stop Condition Trigger */
43
44 /* IICB0STR0 */
45 #define IICB0SSAC BIT(8) /* Ack Flag */
46 #define IICB0SSBS BIT(6) /* Bus Flag */
47 #define IICB0SSSP BIT(4) /* Stop Condition Flag */
48
49 /* IICB0CTL1 */
50 #define IICB0MDSC BIT(7) /* Bus Mode */
51 #define IICB0SLSE BIT(1) /* Start condition output */
52
53 struct rzv2m_i2c_priv {
54 void __iomem *base;
55 struct i2c_adapter adap;
56 struct clk *clk;
57 int bus_mode;
58 struct completion msg_tia_done;
59 u32 iicb0wl;
60 u32 iicb0wh;
61 };
62
63 enum bcr_index {
64 RZV2M_I2C_100K = 0,
65 RZV2M_I2C_400K,
66 };
67
68 struct bitrate_config {
69 unsigned int percent_low;
70 unsigned int min_hold_time_ns;
71 };
72
73 static const struct bitrate_config bitrate_configs[] = {
74 [RZV2M_I2C_100K] = { 47, 3450 },
75 [RZV2M_I2C_400K] = { 52, 900 },
76 };
77
bit_setl(void __iomem * addr,u32 val)78 static inline void bit_setl(void __iomem *addr, u32 val)
79 {
80 writel(readl(addr) | val, addr);
81 }
82
bit_clrl(void __iomem * addr,u32 val)83 static inline void bit_clrl(void __iomem *addr, u32 val)
84 {
85 writel(readl(addr) & ~val, addr);
86 }
87
rzv2m_i2c_tia_irq_handler(int this_irq,void * dev_id)88 static irqreturn_t rzv2m_i2c_tia_irq_handler(int this_irq, void *dev_id)
89 {
90 struct rzv2m_i2c_priv *priv = dev_id;
91
92 complete(&priv->msg_tia_done);
93
94 return IRQ_HANDLED;
95 }
96
97 /* Calculate IICB0WL and IICB0WH */
rzv2m_i2c_clock_calculate(struct device * dev,struct rzv2m_i2c_priv * priv)98 static int rzv2m_i2c_clock_calculate(struct device *dev,
99 struct rzv2m_i2c_priv *priv)
100 {
101 const struct bitrate_config *config;
102 unsigned int hold_time_ns;
103 unsigned int total_pclks;
104 unsigned int trf_pclks;
105 unsigned long pclk_hz;
106 struct i2c_timings t;
107 u32 trf_ns;
108
109 i2c_parse_fw_timings(dev, &t, true);
110
111 pclk_hz = clk_get_rate(priv->clk);
112 total_pclks = pclk_hz / t.bus_freq_hz;
113
114 trf_ns = t.scl_rise_ns + t.scl_fall_ns;
115 trf_pclks = mul_u64_u32_div(pclk_hz, trf_ns, NSEC_PER_SEC);
116
117 /* Config setting */
118 switch (t.bus_freq_hz) {
119 case I2C_MAX_FAST_MODE_FREQ:
120 priv->bus_mode = RZV2M_I2C_400K;
121 break;
122 case I2C_MAX_STANDARD_MODE_FREQ:
123 priv->bus_mode = RZV2M_I2C_100K;
124 break;
125 default:
126 dev_err(dev, "transfer speed is invalid\n");
127 return -EINVAL;
128 }
129 config = &bitrate_configs[priv->bus_mode];
130
131 /* IICB0WL = (percent_low / Transfer clock) x PCLK */
132 priv->iicb0wl = total_pclks * config->percent_low / 100;
133 if (priv->iicb0wl > (BIT(10) - 1))
134 return -EINVAL;
135
136 /* IICB0WH = ((percent_high / Transfer clock) x PCLK) - (tR + tF) */
137 priv->iicb0wh = total_pclks - priv->iicb0wl - trf_pclks;
138 if (priv->iicb0wh > (BIT(10) - 1))
139 return -EINVAL;
140
141 /*
142 * Data hold time must be less than 0.9us in fast mode and
143 * 3.45us in standard mode.
144 * Data hold time = IICB0WL[9:2] / PCLK
145 */
146 hold_time_ns = div64_ul((u64)(priv->iicb0wl >> 2) * NSEC_PER_SEC, pclk_hz);
147 if (hold_time_ns > config->min_hold_time_ns) {
148 dev_err(dev, "data hold time %dns is over %dns\n",
149 hold_time_ns, config->min_hold_time_ns);
150 return -EINVAL;
151 }
152
153 return 0;
154 }
155
rzv2m_i2c_init(struct rzv2m_i2c_priv * priv)156 static void rzv2m_i2c_init(struct rzv2m_i2c_priv *priv)
157 {
158 u32 i2c_ctl0;
159 u32 i2c_ctl1;
160
161 /* i2c disable */
162 writel(0, priv->base + IICB0CTL0);
163
164 /* IICB0CTL1 setting */
165 i2c_ctl1 = IICB0SLSE;
166 if (priv->bus_mode == RZV2M_I2C_400K)
167 i2c_ctl1 |= IICB0MDSC;
168 writel(i2c_ctl1, priv->base + IICB0CTL1);
169
170 /* IICB0WL IICB0WH setting */
171 writel(priv->iicb0wl, priv->base + IICB0WL);
172 writel(priv->iicb0wh, priv->base + IICB0WH);
173
174 /* i2c enable after setting */
175 i2c_ctl0 = IICB0SLWT | IICB0SLAC | IICB0IICE;
176 writel(i2c_ctl0, priv->base + IICB0CTL0);
177 }
178
rzv2m_i2c_write_with_ack(struct rzv2m_i2c_priv * priv,u32 data)179 static int rzv2m_i2c_write_with_ack(struct rzv2m_i2c_priv *priv, u32 data)
180 {
181 unsigned long time_left;
182
183 reinit_completion(&priv->msg_tia_done);
184
185 writel(data, priv->base + IICB0DAT);
186
187 time_left = wait_for_completion_timeout(&priv->msg_tia_done,
188 priv->adap.timeout);
189 if (!time_left)
190 return -ETIMEDOUT;
191
192 /* Confirm ACK */
193 if ((readl(priv->base + IICB0STR0) & IICB0SSAC) != IICB0SSAC)
194 return -ENXIO;
195
196 return 0;
197 }
198
rzv2m_i2c_read_with_ack(struct rzv2m_i2c_priv * priv,u8 * data,bool last)199 static int rzv2m_i2c_read_with_ack(struct rzv2m_i2c_priv *priv, u8 *data,
200 bool last)
201 {
202 unsigned long time_left;
203 u32 data_tmp;
204
205 reinit_completion(&priv->msg_tia_done);
206
207 /* Interrupt request timing : 8th clock */
208 bit_clrl(priv->base + IICB0CTL0, IICB0SLWT);
209
210 /* Exit the wait state */
211 writel(IICB0WRET, priv->base + IICB0TRG);
212
213 /* Wait for transaction */
214 time_left = wait_for_completion_timeout(&priv->msg_tia_done,
215 priv->adap.timeout);
216 if (!time_left)
217 return -ETIMEDOUT;
218
219 if (last) {
220 /* Disable ACK */
221 bit_clrl(priv->base + IICB0CTL0, IICB0SLAC);
222
223 /* Read data*/
224 data_tmp = readl(priv->base + IICB0DAT);
225
226 /* Interrupt request timing : 9th clock */
227 bit_setl(priv->base + IICB0CTL0, IICB0SLWT);
228
229 /* Exit the wait state */
230 writel(IICB0WRET, priv->base + IICB0TRG);
231
232 /* Wait for transaction */
233 time_left = wait_for_completion_timeout(&priv->msg_tia_done,
234 priv->adap.timeout);
235 if (!time_left)
236 return -ETIMEDOUT;
237
238 /* Enable ACK */
239 bit_setl(priv->base + IICB0CTL0, IICB0SLAC);
240 } else {
241 /* Read data */
242 data_tmp = readl(priv->base + IICB0DAT);
243 }
244
245 *data = data_tmp;
246
247 return 0;
248 }
249
rzv2m_i2c_send(struct rzv2m_i2c_priv * priv,struct i2c_msg * msg,unsigned int * count)250 static int rzv2m_i2c_send(struct rzv2m_i2c_priv *priv, struct i2c_msg *msg,
251 unsigned int *count)
252 {
253 unsigned int i;
254 int ret;
255
256 for (i = 0; i < msg->len; i++) {
257 ret = rzv2m_i2c_write_with_ack(priv, msg->buf[i]);
258 if (ret < 0)
259 return ret;
260 }
261 *count = i;
262
263 return 0;
264 }
265
rzv2m_i2c_receive(struct rzv2m_i2c_priv * priv,struct i2c_msg * msg,unsigned int * count)266 static int rzv2m_i2c_receive(struct rzv2m_i2c_priv *priv, struct i2c_msg *msg,
267 unsigned int *count)
268 {
269 unsigned int i;
270 int ret;
271
272 for (i = 0; i < msg->len; i++) {
273 ret = rzv2m_i2c_read_with_ack(priv, &msg->buf[i],
274 (msg->len - 1) == i);
275 if (ret < 0)
276 return ret;
277 }
278 *count = i;
279
280 return 0;
281 }
282
rzv2m_i2c_send_address(struct rzv2m_i2c_priv * priv,struct i2c_msg * msg)283 static int rzv2m_i2c_send_address(struct rzv2m_i2c_priv *priv,
284 struct i2c_msg *msg)
285 {
286 u32 addr;
287 int ret;
288
289 if (msg->flags & I2C_M_TEN) {
290 /* 10-bit address: Send 1st address(extend code) */
291 addr = i2c_10bit_addr_hi_from_msg(msg);
292 ret = rzv2m_i2c_write_with_ack(priv, addr);
293 if (ret)
294 return ret;
295
296 /* 10-bit address: Send 2nd address */
297 addr = i2c_10bit_addr_lo_from_msg(msg);
298 ret = rzv2m_i2c_write_with_ack(priv, addr);
299 } else {
300 /* 7-bit address */
301 addr = i2c_8bit_addr_from_msg(msg);
302 ret = rzv2m_i2c_write_with_ack(priv, addr);
303 }
304
305 return ret;
306 }
307
rzv2m_i2c_stop_condition(struct rzv2m_i2c_priv * priv)308 static int rzv2m_i2c_stop_condition(struct rzv2m_i2c_priv *priv)
309 {
310 u32 value;
311
312 /* Send stop condition */
313 writel(IICB0SPT, priv->base + IICB0TRG);
314 return readl_poll_timeout(priv->base + IICB0STR0,
315 value, value & IICB0SSSP,
316 100, jiffies_to_usecs(priv->adap.timeout));
317 }
318
rzv2m_i2c_xfer_msg(struct rzv2m_i2c_priv * priv,struct i2c_msg * msg,int stop)319 static int rzv2m_i2c_xfer_msg(struct rzv2m_i2c_priv *priv,
320 struct i2c_msg *msg, int stop)
321 {
322 unsigned int count = 0;
323 int ret, read = !!(msg->flags & I2C_M_RD);
324
325 /* Send start condition */
326 writel(IICB0STT, priv->base + IICB0TRG);
327
328 ret = rzv2m_i2c_send_address(priv, msg);
329 if (!ret) {
330 if (read)
331 ret = rzv2m_i2c_receive(priv, msg, &count);
332 else
333 ret = rzv2m_i2c_send(priv, msg, &count);
334
335 if (!ret && stop)
336 ret = rzv2m_i2c_stop_condition(priv);
337 }
338
339 if (ret == -ENXIO)
340 rzv2m_i2c_stop_condition(priv);
341 else if (ret < 0)
342 rzv2m_i2c_init(priv);
343 else
344 ret = count;
345
346 return ret;
347 }
348
rzv2m_i2c_xfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)349 static int rzv2m_i2c_xfer(struct i2c_adapter *adap,
350 struct i2c_msg *msgs, int num)
351 {
352 struct rzv2m_i2c_priv *priv = i2c_get_adapdata(adap);
353 struct device *dev = priv->adap.dev.parent;
354 unsigned int i;
355 int ret;
356
357 ret = pm_runtime_resume_and_get(dev);
358 if (ret < 0)
359 return ret;
360
361 if (readl(priv->base + IICB0STR0) & IICB0SSBS) {
362 ret = -EAGAIN;
363 goto out;
364 }
365
366 /* I2C main transfer */
367 for (i = 0; i < num; i++) {
368 ret = rzv2m_i2c_xfer_msg(priv, &msgs[i], i == (num - 1));
369 if (ret < 0)
370 goto out;
371 }
372 ret = num;
373
374 out:
375 pm_runtime_mark_last_busy(dev);
376 pm_runtime_put_autosuspend(dev);
377
378 return ret;
379 }
380
rzv2m_i2c_func(struct i2c_adapter * adap)381 static u32 rzv2m_i2c_func(struct i2c_adapter *adap)
382 {
383 return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
384 I2C_FUNC_10BIT_ADDR;
385 }
386
rzv2m_i2c_disable(struct device * dev,struct rzv2m_i2c_priv * priv)387 static int rzv2m_i2c_disable(struct device *dev, struct rzv2m_i2c_priv *priv)
388 {
389 int ret;
390
391 ret = pm_runtime_resume_and_get(dev);
392 if (ret < 0)
393 return ret;
394
395 bit_clrl(priv->base + IICB0CTL0, IICB0IICE);
396 pm_runtime_put(dev);
397
398 return 0;
399 }
400
401 static const struct i2c_adapter_quirks rzv2m_i2c_quirks = {
402 .flags = I2C_AQ_NO_ZERO_LEN,
403 };
404
405 static const struct i2c_algorithm rzv2m_i2c_algo = {
406 .xfer = rzv2m_i2c_xfer,
407 .functionality = rzv2m_i2c_func,
408 };
409
rzv2m_i2c_probe(struct platform_device * pdev)410 static int rzv2m_i2c_probe(struct platform_device *pdev)
411 {
412 struct device *dev = &pdev->dev;
413 struct rzv2m_i2c_priv *priv;
414 struct reset_control *rstc;
415 struct i2c_adapter *adap;
416 struct resource *res;
417 int irq, ret;
418
419 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
420 if (!priv)
421 return -ENOMEM;
422
423 priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
424 if (IS_ERR(priv->base))
425 return PTR_ERR(priv->base);
426
427 priv->clk = devm_clk_get(dev, NULL);
428 if (IS_ERR(priv->clk))
429 return dev_err_probe(dev, PTR_ERR(priv->clk), "Can't get clock\n");
430
431 rstc = devm_reset_control_get_shared(dev, NULL);
432 if (IS_ERR(rstc))
433 return dev_err_probe(dev, PTR_ERR(rstc), "Missing reset ctrl\n");
434 /*
435 * The reset also affects other HW that is not under the control
436 * of Linux. Therefore, all we can do is deassert the reset.
437 */
438 reset_control_deassert(rstc);
439
440 irq = platform_get_irq(pdev, 0);
441 if (irq < 0)
442 return irq;
443
444 ret = devm_request_irq(dev, irq, rzv2m_i2c_tia_irq_handler, 0,
445 dev_name(dev), priv);
446 if (ret < 0)
447 return dev_err_probe(dev, ret, "Unable to request irq %d\n", irq);
448
449 adap = &priv->adap;
450 adap->nr = pdev->id;
451 adap->algo = &rzv2m_i2c_algo;
452 adap->quirks = &rzv2m_i2c_quirks;
453 adap->dev.parent = dev;
454 adap->owner = THIS_MODULE;
455 device_set_node(&adap->dev, dev_fwnode(dev));
456 i2c_set_adapdata(adap, priv);
457 strscpy(adap->name, pdev->name, sizeof(adap->name));
458 init_completion(&priv->msg_tia_done);
459
460 ret = rzv2m_i2c_clock_calculate(dev, priv);
461 if (ret < 0)
462 return ret;
463
464 pm_runtime_enable(dev);
465
466 pm_runtime_get_sync(dev);
467 rzv2m_i2c_init(priv);
468 pm_runtime_put(dev);
469
470 platform_set_drvdata(pdev, priv);
471
472 ret = i2c_add_numbered_adapter(adap);
473 if (ret < 0) {
474 rzv2m_i2c_disable(dev, priv);
475 pm_runtime_disable(dev);
476 }
477
478 return ret;
479 }
480
rzv2m_i2c_remove(struct platform_device * pdev)481 static void rzv2m_i2c_remove(struct platform_device *pdev)
482 {
483 struct rzv2m_i2c_priv *priv = platform_get_drvdata(pdev);
484 struct device *dev = priv->adap.dev.parent;
485
486 i2c_del_adapter(&priv->adap);
487 rzv2m_i2c_disable(dev, priv);
488 pm_runtime_disable(dev);
489 }
490
rzv2m_i2c_suspend(struct device * dev)491 static int rzv2m_i2c_suspend(struct device *dev)
492 {
493 struct rzv2m_i2c_priv *priv = dev_get_drvdata(dev);
494
495 return rzv2m_i2c_disable(dev, priv);
496 }
497
rzv2m_i2c_resume(struct device * dev)498 static int rzv2m_i2c_resume(struct device *dev)
499 {
500 struct rzv2m_i2c_priv *priv = dev_get_drvdata(dev);
501 int ret;
502
503 ret = rzv2m_i2c_clock_calculate(dev, priv);
504 if (ret < 0)
505 return ret;
506
507 ret = pm_runtime_resume_and_get(dev);
508 if (ret < 0)
509 return ret;
510
511 rzv2m_i2c_init(priv);
512 pm_runtime_put(dev);
513
514 return 0;
515 }
516
517 static const struct of_device_id rzv2m_i2c_ids[] = {
518 { .compatible = "renesas,rzv2m-i2c" },
519 { }
520 };
521 MODULE_DEVICE_TABLE(of, rzv2m_i2c_ids);
522
523 static const struct dev_pm_ops rzv2m_i2c_pm_ops = {
524 SYSTEM_SLEEP_PM_OPS(rzv2m_i2c_suspend, rzv2m_i2c_resume)
525 };
526
527 static struct platform_driver rzv2m_i2c_driver = {
528 .driver = {
529 .name = "rzv2m-i2c",
530 .of_match_table = rzv2m_i2c_ids,
531 .pm = pm_sleep_ptr(&rzv2m_i2c_pm_ops),
532 },
533 .probe = rzv2m_i2c_probe,
534 .remove = rzv2m_i2c_remove,
535 };
536 module_platform_driver(rzv2m_i2c_driver);
537
538 MODULE_DESCRIPTION("RZ/V2M I2C bus driver");
539 MODULE_AUTHOR("Renesas Electronics Corporation");
540 MODULE_LICENSE("GPL");
541