Merge tag 'spi-fix-v5.5-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi
[linux-2.6-microblaze.git] / drivers / rtc / rtc-brcmstb-waketimer.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright © 2014-2017 Broadcom
4  */
5
6 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
7
8 #include <linux/clk.h>
9 #include <linux/device.h>
10 #include <linux/err.h>
11 #include <linux/init.h>
12 #include <linux/interrupt.h>
13 #include <linux/io.h>
14 #include <linux/irqreturn.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/of.h>
18 #include <linux/platform_device.h>
19 #include <linux/pm.h>
20 #include <linux/pm_wakeup.h>
21 #include <linux/reboot.h>
22 #include <linux/rtc.h>
23 #include <linux/stat.h>
24 #include <linux/suspend.h>
25
26 struct brcmstb_waketmr {
27         struct rtc_device *rtc;
28         struct device *dev;
29         void __iomem *base;
30         int irq;
31         struct notifier_block reboot_notifier;
32         struct clk *clk;
33         u32 rate;
34 };
35
36 #define BRCMSTB_WKTMR_EVENT             0x00
37 #define BRCMSTB_WKTMR_COUNTER           0x04
38 #define BRCMSTB_WKTMR_ALARM             0x08
39 #define BRCMSTB_WKTMR_PRESCALER         0x0C
40 #define BRCMSTB_WKTMR_PRESCALER_VAL     0x10
41
42 #define BRCMSTB_WKTMR_DEFAULT_FREQ      27000000
43
44 static inline void brcmstb_waketmr_clear_alarm(struct brcmstb_waketmr *timer)
45 {
46         writel_relaxed(1, timer->base + BRCMSTB_WKTMR_EVENT);
47         (void)readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
48 }
49
50 static void brcmstb_waketmr_set_alarm(struct brcmstb_waketmr *timer,
51                                       unsigned int secs)
52 {
53         brcmstb_waketmr_clear_alarm(timer);
54
55         /* Make sure we are actually counting in seconds */
56         writel_relaxed(timer->rate, timer->base + BRCMSTB_WKTMR_PRESCALER);
57
58         writel_relaxed(secs + 1, timer->base + BRCMSTB_WKTMR_ALARM);
59 }
60
61 static irqreturn_t brcmstb_waketmr_irq(int irq, void *data)
62 {
63         struct brcmstb_waketmr *timer = data;
64
65         pm_wakeup_event(timer->dev, 0);
66
67         return IRQ_HANDLED;
68 }
69
70 struct wktmr_time {
71         u32 sec;
72         u32 pre;
73 };
74
75 static void wktmr_read(struct brcmstb_waketmr *timer,
76                        struct wktmr_time *t)
77 {
78         u32 tmp;
79
80         do {
81                 t->sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_COUNTER);
82                 tmp = readl_relaxed(timer->base + BRCMSTB_WKTMR_PRESCALER_VAL);
83         } while (tmp >= timer->rate);
84
85         t->pre = timer->rate - tmp;
86 }
87
88 static int brcmstb_waketmr_prepare_suspend(struct brcmstb_waketmr *timer)
89 {
90         struct device *dev = timer->dev;
91         int ret = 0;
92
93         if (device_may_wakeup(dev)) {
94                 ret = enable_irq_wake(timer->irq);
95                 if (ret) {
96                         dev_err(dev, "failed to enable wake-up interrupt\n");
97                         return ret;
98                 }
99         }
100
101         return ret;
102 }
103
104 /* If enabled as a wakeup-source, arm the timer when powering off */
105 static int brcmstb_waketmr_reboot(struct notifier_block *nb,
106                 unsigned long action, void *data)
107 {
108         struct brcmstb_waketmr *timer;
109
110         timer = container_of(nb, struct brcmstb_waketmr, reboot_notifier);
111
112         /* Set timer for cold boot */
113         if (action == SYS_POWER_OFF)
114                 brcmstb_waketmr_prepare_suspend(timer);
115
116         return NOTIFY_DONE;
117 }
118
119 static int brcmstb_waketmr_gettime(struct device *dev,
120                                    struct rtc_time *tm)
121 {
122         struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
123         struct wktmr_time now;
124
125         wktmr_read(timer, &now);
126
127         rtc_time64_to_tm(now.sec, tm);
128
129         return 0;
130 }
131
132 static int brcmstb_waketmr_settime(struct device *dev,
133                                    struct rtc_time *tm)
134 {
135         struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
136         time64_t sec;
137
138         sec = rtc_tm_to_time64(tm);
139
140         writel_relaxed(sec, timer->base + BRCMSTB_WKTMR_COUNTER);
141
142         return 0;
143 }
144
145 static int brcmstb_waketmr_getalarm(struct device *dev,
146                                     struct rtc_wkalrm *alarm)
147 {
148         struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
149         time64_t sec;
150         u32 reg;
151
152         sec = readl_relaxed(timer->base + BRCMSTB_WKTMR_ALARM);
153         if (sec != 0) {
154                 /* Alarm is enabled */
155                 alarm->enabled = 1;
156                 rtc_time64_to_tm(sec, &alarm->time);
157         }
158
159         reg = readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);
160         alarm->pending = !!(reg & 1);
161
162         return 0;
163 }
164
165 static int brcmstb_waketmr_setalarm(struct device *dev,
166                                      struct rtc_wkalrm *alarm)
167 {
168         struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
169         time64_t sec;
170
171         if (alarm->enabled)
172                 sec = rtc_tm_to_time64(&alarm->time);
173         else
174                 sec = 0;
175
176         brcmstb_waketmr_set_alarm(timer, sec);
177
178         return 0;
179 }
180
181 /*
182  * Does not do much but keep the RTC class happy. We always support
183  * alarms.
184  */
185 static int brcmstb_waketmr_alarm_enable(struct device *dev,
186                                         unsigned int enabled)
187 {
188         return 0;
189 }
190
191 static const struct rtc_class_ops brcmstb_waketmr_ops = {
192         .read_time      = brcmstb_waketmr_gettime,
193         .set_time       = brcmstb_waketmr_settime,
194         .read_alarm     = brcmstb_waketmr_getalarm,
195         .set_alarm      = brcmstb_waketmr_setalarm,
196         .alarm_irq_enable = brcmstb_waketmr_alarm_enable,
197 };
198
199 static int brcmstb_waketmr_probe(struct platform_device *pdev)
200 {
201         struct device *dev = &pdev->dev;
202         struct brcmstb_waketmr *timer;
203         int ret;
204
205         timer = devm_kzalloc(dev, sizeof(*timer), GFP_KERNEL);
206         if (!timer)
207                 return -ENOMEM;
208
209         platform_set_drvdata(pdev, timer);
210         timer->dev = dev;
211
212         timer->base = devm_platform_ioremap_resource(pdev, 0);
213         if (IS_ERR(timer->base))
214                 return PTR_ERR(timer->base);
215
216         timer->rtc = devm_rtc_allocate_device(dev);
217         if (IS_ERR(timer->rtc))
218                 return PTR_ERR(timer->rtc);
219
220         /*
221          * Set wakeup capability before requesting wakeup interrupt, so we can
222          * process boot-time "wakeups" (e.g., from S5 soft-off)
223          */
224         device_set_wakeup_capable(dev, true);
225         device_wakeup_enable(dev);
226
227         timer->irq = platform_get_irq(pdev, 0);
228         if (timer->irq < 0)
229                 return -ENODEV;
230
231         timer->clk = devm_clk_get(dev, NULL);
232         if (!IS_ERR(timer->clk)) {
233                 ret = clk_prepare_enable(timer->clk);
234                 if (ret)
235                         return ret;
236                 timer->rate = clk_get_rate(timer->clk);
237                 if (!timer->rate)
238                         timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
239         } else {
240                 timer->rate = BRCMSTB_WKTMR_DEFAULT_FREQ;
241                 timer->clk = NULL;
242         }
243
244         ret = devm_request_irq(dev, timer->irq, brcmstb_waketmr_irq, 0,
245                                "brcmstb-waketimer", timer);
246         if (ret < 0)
247                 goto err_clk;
248
249         timer->reboot_notifier.notifier_call = brcmstb_waketmr_reboot;
250         register_reboot_notifier(&timer->reboot_notifier);
251
252         timer->rtc->ops = &brcmstb_waketmr_ops;
253         timer->rtc->range_max = U32_MAX;
254
255         ret = rtc_register_device(timer->rtc);
256         if (ret)
257                 goto err_notifier;
258
259         dev_info(dev, "registered, with irq %d\n", timer->irq);
260
261         return 0;
262
263 err_notifier:
264         unregister_reboot_notifier(&timer->reboot_notifier);
265
266 err_clk:
267         if (timer->clk)
268                 clk_disable_unprepare(timer->clk);
269
270         return ret;
271 }
272
273 static int brcmstb_waketmr_remove(struct platform_device *pdev)
274 {
275         struct brcmstb_waketmr *timer = dev_get_drvdata(&pdev->dev);
276
277         unregister_reboot_notifier(&timer->reboot_notifier);
278         clk_disable_unprepare(timer->clk);
279
280         return 0;
281 }
282
283 #ifdef CONFIG_PM_SLEEP
284 static int brcmstb_waketmr_suspend(struct device *dev)
285 {
286         struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
287
288         return brcmstb_waketmr_prepare_suspend(timer);
289 }
290
291 static int brcmstb_waketmr_resume(struct device *dev)
292 {
293         struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
294         int ret;
295
296         if (!device_may_wakeup(dev))
297                 return 0;
298
299         ret = disable_irq_wake(timer->irq);
300
301         brcmstb_waketmr_clear_alarm(timer);
302
303         return ret;
304 }
305 #endif /* CONFIG_PM_SLEEP */
306
307 static SIMPLE_DEV_PM_OPS(brcmstb_waketmr_pm_ops,
308                          brcmstb_waketmr_suspend, brcmstb_waketmr_resume);
309
310 static const struct of_device_id brcmstb_waketmr_of_match[] = {
311         { .compatible = "brcm,brcmstb-waketimer" },
312         { /* sentinel */ },
313 };
314
315 static struct platform_driver brcmstb_waketmr_driver = {
316         .probe                  = brcmstb_waketmr_probe,
317         .remove                 = brcmstb_waketmr_remove,
318         .driver = {
319                 .name           = "brcmstb-waketimer",
320                 .pm             = &brcmstb_waketmr_pm_ops,
321                 .of_match_table = of_match_ptr(brcmstb_waketmr_of_match),
322         }
323 };
324 module_platform_driver(brcmstb_waketmr_driver);
325
326 MODULE_LICENSE("GPL v2");
327 MODULE_AUTHOR("Brian Norris");
328 MODULE_AUTHOR("Markus Mayer");
329 MODULE_DESCRIPTION("Wake-up timer driver for STB chips");