1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Driver for MediaTek SoC based RTC
4 *
5 * Copyright (C) 2017 Sean Wang <sean.wang@mediatek.com>
6 */
7
8 #include <linux/clk.h>
9 #include <linux/interrupt.h>
10 #include <linux/io.h>
11 #include <linux/mod_devicetable.h>
12 #include <linux/module.h>
13 #include <linux/platform_device.h>
14 #include <linux/rtc.h>
15
16 #define MTK_RTC_DEV KBUILD_MODNAME
17
18 #define MTK_RTC_PWRCHK1 0x4
19 #define RTC_PWRCHK1_MAGIC 0xc6
20
21 #define MTK_RTC_PWRCHK2 0x8
22 #define RTC_PWRCHK2_MAGIC 0x9a
23
24 #define MTK_RTC_KEY 0xc
25 #define RTC_KEY_MAGIC 0x59
26
27 #define MTK_RTC_PROT1 0x10
28 #define RTC_PROT1_MAGIC 0xa3
29
30 #define MTK_RTC_PROT2 0x14
31 #define RTC_PROT2_MAGIC 0x57
32
33 #define MTK_RTC_PROT3 0x18
34 #define RTC_PROT3_MAGIC 0x67
35
36 #define MTK_RTC_PROT4 0x1c
37 #define RTC_PROT4_MAGIC 0xd2
38
39 #define MTK_RTC_CTL 0x20
40 #define RTC_RC_STOP BIT(0)
41
42 #define MTK_RTC_DEBNCE 0x2c
43 #define RTC_DEBNCE_MASK GENMASK(2, 0)
44
45 #define MTK_RTC_INT 0x30
46 #define RTC_INT_AL_STA BIT(4)
47
48 /*
49 * Ranges from 0x40 to 0x78 provide RTC time setup for year, month,
50 * day of month, day of week, hour, minute and second.
51 */
52 #define MTK_RTC_TREG(_t, _f) (0x40 + (0x4 * (_f)) + ((_t) * 0x20))
53
54 #define MTK_RTC_AL_CTL 0x7c
55 #define RTC_AL_EN BIT(0)
56 #define RTC_AL_ALL GENMASK(7, 0)
57
58 /*
59 * The offset is used in the translation for the year between in struct
60 * rtc_time and in hardware register MTK_RTC_TREG(x,MTK_YEA)
61 */
62 #define MTK_RTC_TM_YR_OFFSET 100
63
64 /*
65 * The lowest value for the valid tm_year. RTC hardware would take incorrectly
66 * tm_year 100 as not a leap year and thus it is also required being excluded
67 * from the valid options.
68 */
69 #define MTK_RTC_TM_YR_L (MTK_RTC_TM_YR_OFFSET + 1)
70
71 /*
72 * The most year the RTC can hold is 99 and the next to 99 in year register
73 * would be wraparound to 0, for MT7622.
74 */
75 #define MTK_RTC_HW_YR_LIMIT 99
76
77 /* The highest value for the valid tm_year */
78 #define MTK_RTC_TM_YR_H (MTK_RTC_TM_YR_OFFSET + MTK_RTC_HW_YR_LIMIT)
79
80 /* Simple macro helps to check whether the hardware supports the tm_year */
81 #define MTK_RTC_TM_YR_VALID(_y) ((_y) >= MTK_RTC_TM_YR_L && \
82 (_y) <= MTK_RTC_TM_YR_H)
83
84 /* Types of the function the RTC provides are time counter and alarm. */
85 enum {
86 MTK_TC,
87 MTK_AL,
88 };
89
90 /* Indexes are used for the pointer to relevant registers in MTK_RTC_TREG */
91 enum {
92 MTK_YEA,
93 MTK_MON,
94 MTK_DOM,
95 MTK_DOW,
96 MTK_HOU,
97 MTK_MIN,
98 MTK_SEC
99 };
100
101 struct mtk_rtc {
102 struct rtc_device *rtc;
103 void __iomem *base;
104 int irq;
105 struct clk *clk;
106 };
107
mtk_w32(struct mtk_rtc * rtc,u32 reg,u32 val)108 static void mtk_w32(struct mtk_rtc *rtc, u32 reg, u32 val)
109 {
110 writel_relaxed(val, rtc->base + reg);
111 }
112
mtk_r32(struct mtk_rtc * rtc,u32 reg)113 static u32 mtk_r32(struct mtk_rtc *rtc, u32 reg)
114 {
115 return readl_relaxed(rtc->base + reg);
116 }
117
mtk_rmw(struct mtk_rtc * rtc,u32 reg,u32 mask,u32 set)118 static void mtk_rmw(struct mtk_rtc *rtc, u32 reg, u32 mask, u32 set)
119 {
120 u32 val;
121
122 val = mtk_r32(rtc, reg);
123 val &= ~mask;
124 val |= set;
125 mtk_w32(rtc, reg, val);
126 }
127
mtk_set(struct mtk_rtc * rtc,u32 reg,u32 val)128 static void mtk_set(struct mtk_rtc *rtc, u32 reg, u32 val)
129 {
130 mtk_rmw(rtc, reg, 0, val);
131 }
132
mtk_clr(struct mtk_rtc * rtc,u32 reg,u32 val)133 static void mtk_clr(struct mtk_rtc *rtc, u32 reg, u32 val)
134 {
135 mtk_rmw(rtc, reg, val, 0);
136 }
137
mtk_rtc_hw_init(struct mtk_rtc * hw)138 static void mtk_rtc_hw_init(struct mtk_rtc *hw)
139 {
140 /* The setup of the init sequence is for allowing RTC got to work */
141 mtk_w32(hw, MTK_RTC_PWRCHK1, RTC_PWRCHK1_MAGIC);
142 mtk_w32(hw, MTK_RTC_PWRCHK2, RTC_PWRCHK2_MAGIC);
143 mtk_w32(hw, MTK_RTC_KEY, RTC_KEY_MAGIC);
144 mtk_w32(hw, MTK_RTC_PROT1, RTC_PROT1_MAGIC);
145 mtk_w32(hw, MTK_RTC_PROT2, RTC_PROT2_MAGIC);
146 mtk_w32(hw, MTK_RTC_PROT3, RTC_PROT3_MAGIC);
147 mtk_w32(hw, MTK_RTC_PROT4, RTC_PROT4_MAGIC);
148 mtk_rmw(hw, MTK_RTC_DEBNCE, RTC_DEBNCE_MASK, 0);
149 mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP);
150 }
151
mtk_rtc_get_alarm_or_time(struct mtk_rtc * hw,struct rtc_time * tm,int time_alarm)152 static void mtk_rtc_get_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm,
153 int time_alarm)
154 {
155 u32 year, mon, mday, wday, hour, min, sec;
156
157 /*
158 * Read again until the field of the second is not changed which
159 * ensures all fields in the consistent state. Note that MTK_SEC must
160 * be read first. In this way, it guarantees the others remain not
161 * changed when the results for two MTK_SEC consecutive reads are same.
162 */
163 do {
164 sec = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC));
165 min = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN));
166 hour = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU));
167 wday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW));
168 mday = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM));
169 mon = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_MON));
170 year = mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA));
171 } while (sec != mtk_r32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC)));
172
173 tm->tm_sec = sec;
174 tm->tm_min = min;
175 tm->tm_hour = hour;
176 tm->tm_wday = wday;
177 tm->tm_mday = mday;
178 tm->tm_mon = mon - 1;
179
180 /* Rebase to the absolute year which userspace queries */
181 tm->tm_year = year + MTK_RTC_TM_YR_OFFSET;
182 }
183
mtk_rtc_set_alarm_or_time(struct mtk_rtc * hw,struct rtc_time * tm,int time_alarm)184 static void mtk_rtc_set_alarm_or_time(struct mtk_rtc *hw, struct rtc_time *tm,
185 int time_alarm)
186 {
187 u32 year;
188
189 /* Rebase to the relative year which RTC hardware requires */
190 year = tm->tm_year - MTK_RTC_TM_YR_OFFSET;
191
192 mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_YEA), year);
193 mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MON), tm->tm_mon + 1);
194 mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOW), tm->tm_wday);
195 mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_DOM), tm->tm_mday);
196 mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_HOU), tm->tm_hour);
197 mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_MIN), tm->tm_min);
198 mtk_w32(hw, MTK_RTC_TREG(time_alarm, MTK_SEC), tm->tm_sec);
199 }
200
mtk_rtc_alarmirq(int irq,void * id)201 static irqreturn_t mtk_rtc_alarmirq(int irq, void *id)
202 {
203 struct mtk_rtc *hw = (struct mtk_rtc *)id;
204 u32 irq_sta;
205
206 irq_sta = mtk_r32(hw, MTK_RTC_INT);
207 if (irq_sta & RTC_INT_AL_STA) {
208 /* Stop alarm also implicitly disables the alarm interrupt */
209 mtk_w32(hw, MTK_RTC_AL_CTL, 0);
210 rtc_update_irq(hw->rtc, 1, RTC_IRQF | RTC_AF);
211
212 /* Ack alarm interrupt status */
213 mtk_w32(hw, MTK_RTC_INT, RTC_INT_AL_STA);
214 return IRQ_HANDLED;
215 }
216
217 return IRQ_NONE;
218 }
219
mtk_rtc_gettime(struct device * dev,struct rtc_time * tm)220 static int mtk_rtc_gettime(struct device *dev, struct rtc_time *tm)
221 {
222 struct mtk_rtc *hw = dev_get_drvdata(dev);
223
224 mtk_rtc_get_alarm_or_time(hw, tm, MTK_TC);
225
226 return 0;
227 }
228
mtk_rtc_settime(struct device * dev,struct rtc_time * tm)229 static int mtk_rtc_settime(struct device *dev, struct rtc_time *tm)
230 {
231 struct mtk_rtc *hw = dev_get_drvdata(dev);
232
233 if (!MTK_RTC_TM_YR_VALID(tm->tm_year))
234 return -EINVAL;
235
236 /* Stop time counter before setting a new one*/
237 mtk_set(hw, MTK_RTC_CTL, RTC_RC_STOP);
238
239 mtk_rtc_set_alarm_or_time(hw, tm, MTK_TC);
240
241 /* Restart the time counter */
242 mtk_clr(hw, MTK_RTC_CTL, RTC_RC_STOP);
243
244 return 0;
245 }
246
mtk_rtc_getalarm(struct device * dev,struct rtc_wkalrm * wkalrm)247 static int mtk_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
248 {
249 struct mtk_rtc *hw = dev_get_drvdata(dev);
250 struct rtc_time *alrm_tm = &wkalrm->time;
251
252 mtk_rtc_get_alarm_or_time(hw, alrm_tm, MTK_AL);
253
254 wkalrm->enabled = !!(mtk_r32(hw, MTK_RTC_AL_CTL) & RTC_AL_EN);
255 wkalrm->pending = !!(mtk_r32(hw, MTK_RTC_INT) & RTC_INT_AL_STA);
256
257 return 0;
258 }
259
mtk_rtc_setalarm(struct device * dev,struct rtc_wkalrm * wkalrm)260 static int mtk_rtc_setalarm(struct device *dev, struct rtc_wkalrm *wkalrm)
261 {
262 struct mtk_rtc *hw = dev_get_drvdata(dev);
263 struct rtc_time *alrm_tm = &wkalrm->time;
264
265 if (!MTK_RTC_TM_YR_VALID(alrm_tm->tm_year))
266 return -EINVAL;
267
268 /*
269 * Stop the alarm also implicitly including disables interrupt before
270 * setting a new one.
271 */
272 mtk_clr(hw, MTK_RTC_AL_CTL, RTC_AL_EN);
273
274 /*
275 * Avoid contention between mtk_rtc_setalarm and IRQ handler so that
276 * disabling the interrupt and awaiting for pending IRQ handler to
277 * complete.
278 */
279 synchronize_irq(hw->irq);
280
281 mtk_rtc_set_alarm_or_time(hw, alrm_tm, MTK_AL);
282
283 /* Restart the alarm with the new setup */
284 mtk_w32(hw, MTK_RTC_AL_CTL, RTC_AL_ALL);
285
286 return 0;
287 }
288
289 static const struct rtc_class_ops mtk_rtc_ops = {
290 .read_time = mtk_rtc_gettime,
291 .set_time = mtk_rtc_settime,
292 .read_alarm = mtk_rtc_getalarm,
293 .set_alarm = mtk_rtc_setalarm,
294 };
295
296 static const struct of_device_id mtk_rtc_match[] = {
297 { .compatible = "mediatek,mt7622-rtc" },
298 { .compatible = "mediatek,soc-rtc" },
299 {},
300 };
301 MODULE_DEVICE_TABLE(of, mtk_rtc_match);
302
mtk_rtc_probe(struct platform_device * pdev)303 static int mtk_rtc_probe(struct platform_device *pdev)
304 {
305 struct mtk_rtc *hw;
306 int ret;
307
308 hw = devm_kzalloc(&pdev->dev, sizeof(*hw), GFP_KERNEL);
309 if (!hw)
310 return -ENOMEM;
311
312 platform_set_drvdata(pdev, hw);
313
314 hw->base = devm_platform_ioremap_resource(pdev, 0);
315 if (IS_ERR(hw->base))
316 return PTR_ERR(hw->base);
317
318 hw->clk = devm_clk_get(&pdev->dev, "rtc");
319 if (IS_ERR(hw->clk)) {
320 dev_err(&pdev->dev, "No clock\n");
321 return PTR_ERR(hw->clk);
322 }
323
324 ret = clk_prepare_enable(hw->clk);
325 if (ret)
326 return ret;
327
328 hw->irq = platform_get_irq(pdev, 0);
329 if (hw->irq < 0) {
330 ret = hw->irq;
331 goto err;
332 }
333
334 ret = devm_request_irq(&pdev->dev, hw->irq, mtk_rtc_alarmirq,
335 0, dev_name(&pdev->dev), hw);
336 if (ret) {
337 dev_err(&pdev->dev, "Can't request IRQ\n");
338 goto err;
339 }
340
341 mtk_rtc_hw_init(hw);
342
343 device_init_wakeup(&pdev->dev, true);
344
345 hw->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
346 &mtk_rtc_ops, THIS_MODULE);
347 if (IS_ERR(hw->rtc)) {
348 ret = PTR_ERR(hw->rtc);
349 dev_err(&pdev->dev, "Unable to register device\n");
350 goto err;
351 }
352
353 return 0;
354 err:
355 clk_disable_unprepare(hw->clk);
356
357 return ret;
358 }
359
mtk_rtc_remove(struct platform_device * pdev)360 static void mtk_rtc_remove(struct platform_device *pdev)
361 {
362 struct mtk_rtc *hw = platform_get_drvdata(pdev);
363
364 clk_disable_unprepare(hw->clk);
365 }
366
367 #ifdef CONFIG_PM_SLEEP
mtk_rtc_suspend(struct device * dev)368 static int mtk_rtc_suspend(struct device *dev)
369 {
370 struct mtk_rtc *hw = dev_get_drvdata(dev);
371
372 if (device_may_wakeup(dev))
373 enable_irq_wake(hw->irq);
374
375 return 0;
376 }
377
mtk_rtc_resume(struct device * dev)378 static int mtk_rtc_resume(struct device *dev)
379 {
380 struct mtk_rtc *hw = dev_get_drvdata(dev);
381
382 if (device_may_wakeup(dev))
383 disable_irq_wake(hw->irq);
384
385 return 0;
386 }
387
388 static SIMPLE_DEV_PM_OPS(mtk_rtc_pm_ops, mtk_rtc_suspend, mtk_rtc_resume);
389
390 #define MTK_RTC_PM_OPS (&mtk_rtc_pm_ops)
391 #else /* CONFIG_PM */
392 #define MTK_RTC_PM_OPS NULL
393 #endif /* CONFIG_PM */
394
395 static struct platform_driver mtk_rtc_driver = {
396 .probe = mtk_rtc_probe,
397 .remove_new = mtk_rtc_remove,
398 .driver = {
399 .name = MTK_RTC_DEV,
400 .of_match_table = mtk_rtc_match,
401 .pm = MTK_RTC_PM_OPS,
402 },
403 };
404
405 module_platform_driver(mtk_rtc_driver);
406
407 MODULE_DESCRIPTION("MediaTek SoC based RTC Driver");
408 MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
409 MODULE_LICENSE("GPL");
410