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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2010 NXP Semiconductors
4 */
5
6#include <linux/kernel.h>
7#include <linux/module.h>
8#include <linux/init.h>
9#include <linux/platform_device.h>
10#include <linux/spinlock.h>
11#include <linux/rtc.h>
12#include <linux/slab.h>
13#include <linux/io.h>
14#include <linux/of.h>
15
16/*
17 * Clock and Power control register offsets
18 */
19#define LPC32XX_RTC_UCOUNT 0x00
20#define LPC32XX_RTC_DCOUNT 0x04
21#define LPC32XX_RTC_MATCH0 0x08
22#define LPC32XX_RTC_MATCH1 0x0C
23#define LPC32XX_RTC_CTRL 0x10
24#define LPC32XX_RTC_INTSTAT 0x14
25#define LPC32XX_RTC_KEY 0x18
26#define LPC32XX_RTC_SRAM 0x80
27
28#define LPC32XX_RTC_CTRL_MATCH0 (1 << 0)
29#define LPC32XX_RTC_CTRL_MATCH1 (1 << 1)
30#define LPC32XX_RTC_CTRL_ONSW_MATCH0 (1 << 2)
31#define LPC32XX_RTC_CTRL_ONSW_MATCH1 (1 << 3)
32#define LPC32XX_RTC_CTRL_SW_RESET (1 << 4)
33#define LPC32XX_RTC_CTRL_CNTR_DIS (1 << 6)
34#define LPC32XX_RTC_CTRL_ONSW_FORCE_HI (1 << 7)
35
36#define LPC32XX_RTC_INTSTAT_MATCH0 (1 << 0)
37#define LPC32XX_RTC_INTSTAT_MATCH1 (1 << 1)
38#define LPC32XX_RTC_INTSTAT_ONSW (1 << 2)
39
40#define LPC32XX_RTC_KEY_ONSW_LOADVAL 0xB5C13F27
41
42#define rtc_readl(dev, reg) \
43 __raw_readl((dev)->rtc_base + (reg))
44#define rtc_writel(dev, reg, val) \
45 __raw_writel((val), (dev)->rtc_base + (reg))
46
47struct lpc32xx_rtc {
48 void __iomem *rtc_base;
49 int irq;
50 unsigned char alarm_enabled;
51 struct rtc_device *rtc;
52 spinlock_t lock;
53};
54
55static int lpc32xx_rtc_read_time(struct device *dev, struct rtc_time *time)
56{
57 unsigned long elapsed_sec;
58 struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
59
60 elapsed_sec = rtc_readl(rtc, LPC32XX_RTC_UCOUNT);
61 rtc_time64_to_tm(elapsed_sec, time);
62
63 return 0;
64}
65
66static int lpc32xx_rtc_set_time(struct device *dev, struct rtc_time *time)
67{
68 struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
69 u32 secs = rtc_tm_to_time64(time);
70 u32 tmp;
71
72 spin_lock_irq(&rtc->lock);
73
74 /* RTC must be disabled during count update */
75 tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
76 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp | LPC32XX_RTC_CTRL_CNTR_DIS);
77 rtc_writel(rtc, LPC32XX_RTC_UCOUNT, secs);
78 rtc_writel(rtc, LPC32XX_RTC_DCOUNT, 0xFFFFFFFF - secs);
79 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp &= ~LPC32XX_RTC_CTRL_CNTR_DIS);
80
81 spin_unlock_irq(&rtc->lock);
82
83 return 0;
84}
85
86static int lpc32xx_rtc_read_alarm(struct device *dev,
87 struct rtc_wkalrm *wkalrm)
88{
89 struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
90
91 rtc_time64_to_tm(rtc_readl(rtc, LPC32XX_RTC_MATCH0), &wkalrm->time);
92 wkalrm->enabled = rtc->alarm_enabled;
93 wkalrm->pending = !!(rtc_readl(rtc, LPC32XX_RTC_INTSTAT) &
94 LPC32XX_RTC_INTSTAT_MATCH0);
95
96 return rtc_valid_tm(&wkalrm->time);
97}
98
99static int lpc32xx_rtc_set_alarm(struct device *dev,
100 struct rtc_wkalrm *wkalrm)
101{
102 struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
103 unsigned long alarmsecs;
104 u32 tmp;
105
106 alarmsecs = rtc_tm_to_time64(&wkalrm->time);
107
108 spin_lock_irq(&rtc->lock);
109
110 /* Disable alarm during update */
111 tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
112 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp & ~LPC32XX_RTC_CTRL_MATCH0);
113
114 rtc_writel(rtc, LPC32XX_RTC_MATCH0, alarmsecs);
115
116 rtc->alarm_enabled = wkalrm->enabled;
117 if (wkalrm->enabled) {
118 rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
119 LPC32XX_RTC_INTSTAT_MATCH0);
120 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp |
121 LPC32XX_RTC_CTRL_MATCH0);
122 }
123
124 spin_unlock_irq(&rtc->lock);
125
126 return 0;
127}
128
129static int lpc32xx_rtc_alarm_irq_enable(struct device *dev,
130 unsigned int enabled)
131{
132 struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
133 u32 tmp;
134
135 spin_lock_irq(&rtc->lock);
136 tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
137
138 if (enabled) {
139 rtc->alarm_enabled = 1;
140 tmp |= LPC32XX_RTC_CTRL_MATCH0;
141 } else {
142 rtc->alarm_enabled = 0;
143 tmp &= ~LPC32XX_RTC_CTRL_MATCH0;
144 }
145
146 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
147 spin_unlock_irq(&rtc->lock);
148
149 return 0;
150}
151
152static irqreturn_t lpc32xx_rtc_alarm_interrupt(int irq, void *dev)
153{
154 struct lpc32xx_rtc *rtc = dev;
155
156 spin_lock(&rtc->lock);
157
158 /* Disable alarm interrupt */
159 rtc_writel(rtc, LPC32XX_RTC_CTRL,
160 rtc_readl(rtc, LPC32XX_RTC_CTRL) &
161 ~LPC32XX_RTC_CTRL_MATCH0);
162 rtc->alarm_enabled = 0;
163
164 /*
165 * Write a large value to the match value so the RTC won't
166 * keep firing the match status
167 */
168 rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
169 rtc_writel(rtc, LPC32XX_RTC_INTSTAT, LPC32XX_RTC_INTSTAT_MATCH0);
170
171 spin_unlock(&rtc->lock);
172
173 rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
174
175 return IRQ_HANDLED;
176}
177
178static const struct rtc_class_ops lpc32xx_rtc_ops = {
179 .read_time = lpc32xx_rtc_read_time,
180 .set_time = lpc32xx_rtc_set_time,
181 .read_alarm = lpc32xx_rtc_read_alarm,
182 .set_alarm = lpc32xx_rtc_set_alarm,
183 .alarm_irq_enable = lpc32xx_rtc_alarm_irq_enable,
184};
185
186static int lpc32xx_rtc_probe(struct platform_device *pdev)
187{
188 struct lpc32xx_rtc *rtc;
189 int err;
190 u32 tmp;
191
192 rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
193 if (unlikely(!rtc))
194 return -ENOMEM;
195
196 rtc->rtc_base = devm_platform_ioremap_resource(pdev, 0);
197 if (IS_ERR(rtc->rtc_base))
198 return PTR_ERR(rtc->rtc_base);
199
200 spin_lock_init(&rtc->lock);
201
202 /*
203 * The RTC is on a separate power domain and can keep it's state
204 * across a chip power cycle. If the RTC has never been previously
205 * setup, then set it up now for the first time.
206 */
207 tmp = rtc_readl(rtc, LPC32XX_RTC_CTRL);
208 if (rtc_readl(rtc, LPC32XX_RTC_KEY) != LPC32XX_RTC_KEY_ONSW_LOADVAL) {
209 tmp &= ~(LPC32XX_RTC_CTRL_SW_RESET |
210 LPC32XX_RTC_CTRL_CNTR_DIS |
211 LPC32XX_RTC_CTRL_MATCH0 |
212 LPC32XX_RTC_CTRL_MATCH1 |
213 LPC32XX_RTC_CTRL_ONSW_MATCH0 |
214 LPC32XX_RTC_CTRL_ONSW_MATCH1 |
215 LPC32XX_RTC_CTRL_ONSW_FORCE_HI);
216 rtc_writel(rtc, LPC32XX_RTC_CTRL, tmp);
217
218 /* Clear latched interrupt states */
219 rtc_writel(rtc, LPC32XX_RTC_MATCH0, 0xFFFFFFFF);
220 rtc_writel(rtc, LPC32XX_RTC_INTSTAT,
221 LPC32XX_RTC_INTSTAT_MATCH0 |
222 LPC32XX_RTC_INTSTAT_MATCH1 |
223 LPC32XX_RTC_INTSTAT_ONSW);
224
225 /* Write key value to RTC so it won't reload on reset */
226 rtc_writel(rtc, LPC32XX_RTC_KEY,
227 LPC32XX_RTC_KEY_ONSW_LOADVAL);
228 } else {
229 rtc_writel(rtc, LPC32XX_RTC_CTRL,
230 tmp & ~LPC32XX_RTC_CTRL_MATCH0);
231 }
232
233 platform_set_drvdata(pdev, rtc);
234
235 rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
236 if (IS_ERR(rtc->rtc))
237 return PTR_ERR(rtc->rtc);
238
239 rtc->rtc->ops = &lpc32xx_rtc_ops;
240 rtc->rtc->range_max = U32_MAX;
241
242 err = devm_rtc_register_device(rtc->rtc);
243 if (err)
244 return err;
245
246 /*
247 * IRQ is enabled after device registration in case alarm IRQ
248 * is pending upon suspend exit.
249 */
250 rtc->irq = platform_get_irq(pdev, 0);
251 if (rtc->irq < 0) {
252 dev_warn(&pdev->dev, "Can't get interrupt resource\n");
253 } else {
254 if (devm_request_irq(&pdev->dev, rtc->irq,
255 lpc32xx_rtc_alarm_interrupt,
256 0, pdev->name, rtc) < 0) {
257 dev_warn(&pdev->dev, "Can't request interrupt.\n");
258 rtc->irq = -1;
259 } else {
260 device_init_wakeup(&pdev->dev, true);
261 }
262 }
263
264 return 0;
265}
266
267#ifdef CONFIG_PM
268static int lpc32xx_rtc_suspend(struct device *dev)
269{
270 struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
271
272 if (rtc->irq >= 0) {
273 if (device_may_wakeup(dev))
274 enable_irq_wake(rtc->irq);
275 else
276 disable_irq_wake(rtc->irq);
277 }
278
279 return 0;
280}
281
282static int lpc32xx_rtc_resume(struct device *dev)
283{
284 struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
285
286 if (rtc->irq >= 0 && device_may_wakeup(dev))
287 disable_irq_wake(rtc->irq);
288
289 return 0;
290}
291
292/* Unconditionally disable the alarm */
293static int lpc32xx_rtc_freeze(struct device *dev)
294{
295 struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
296
297 spin_lock_irq(&rtc->lock);
298
299 rtc_writel(rtc, LPC32XX_RTC_CTRL,
300 rtc_readl(rtc, LPC32XX_RTC_CTRL) &
301 ~LPC32XX_RTC_CTRL_MATCH0);
302
303 spin_unlock_irq(&rtc->lock);
304
305 return 0;
306}
307
308static int lpc32xx_rtc_thaw(struct device *dev)
309{
310 struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
311
312 if (rtc->alarm_enabled) {
313 spin_lock_irq(&rtc->lock);
314
315 rtc_writel(rtc, LPC32XX_RTC_CTRL,
316 rtc_readl(rtc, LPC32XX_RTC_CTRL) |
317 LPC32XX_RTC_CTRL_MATCH0);
318
319 spin_unlock_irq(&rtc->lock);
320 }
321
322 return 0;
323}
324
325static const struct dev_pm_ops lpc32xx_rtc_pm_ops = {
326 .suspend = lpc32xx_rtc_suspend,
327 .resume = lpc32xx_rtc_resume,
328 .freeze = lpc32xx_rtc_freeze,
329 .thaw = lpc32xx_rtc_thaw,
330 .restore = lpc32xx_rtc_resume
331};
332
333#define LPC32XX_RTC_PM_OPS (&lpc32xx_rtc_pm_ops)
334#else
335#define LPC32XX_RTC_PM_OPS NULL
336#endif
337
338#ifdef CONFIG_OF
339static const struct of_device_id lpc32xx_rtc_match[] = {
340 { .compatible = "nxp,lpc3220-rtc" },
341 { }
342};
343MODULE_DEVICE_TABLE(of, lpc32xx_rtc_match);
344#endif
345
346static struct platform_driver lpc32xx_rtc_driver = {
347 .probe = lpc32xx_rtc_probe,
348 .driver = {
349 .name = "rtc-lpc32xx",
350 .pm = LPC32XX_RTC_PM_OPS,
351 .of_match_table = of_match_ptr(lpc32xx_rtc_match),
352 },
353};
354
355module_platform_driver(lpc32xx_rtc_driver);
356
357MODULE_AUTHOR("Kevin Wells <[email protected]");
358MODULE_DESCRIPTION("RTC driver for the LPC32xx SoC");
359MODULE_LICENSE("GPL");
360MODULE_ALIAS("platform:rtc-lpc32xx");