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17#include <linux/clk.h>
18#include <linux/delay.h>
19#include <linux/init.h>
20#include <linux/io.h>
21#include <linux/irq.h>
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/of.h>
25#include <linux/of_irq.h>
26#include <linux/platform_device.h>
27#include <linux/rtc.h>
28
29#include <dt-bindings/mfd/st-lpc.h>
30
31
32#define LPC_LPT_LSB_OFF 0x400
33#define LPC_LPT_MSB_OFF 0x404
34#define LPC_LPT_START_OFF 0x408
35
36
37#define LPC_LPA_LSB_OFF 0x410
38#define LPC_LPA_MSB_OFF 0x414
39#define LPC_LPA_START_OFF 0x418
40
41
42#define LPC_WDT_OFF 0x510
43#define LPC_WDT_FLAG_OFF 0x514
44
45struct st_rtc {
46 struct rtc_device *rtc_dev;
47 struct rtc_wkalrm alarm;
48 struct resource *res;
49 struct clk *clk;
50 unsigned long clkrate;
51 void __iomem *ioaddr;
52 bool irq_enabled:1;
53 spinlock_t lock;
54 short irq;
55};
56
57static void st_rtc_set_hw_alarm(struct st_rtc *rtc,
58 unsigned long msb, unsigned long lsb)
59{
60 unsigned long flags;
61
62 spin_lock_irqsave(&rtc->lock, flags);
63
64 writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
65
66 writel_relaxed(msb, rtc->ioaddr + LPC_LPA_MSB_OFF);
67 writel_relaxed(lsb, rtc->ioaddr + LPC_LPA_LSB_OFF);
68 writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
69
70 writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
71
72 spin_unlock_irqrestore(&rtc->lock, flags);
73}
74
75static irqreturn_t st_rtc_handler(int this_irq, void *data)
76{
77 struct st_rtc *rtc = (struct st_rtc *)data;
78
79 rtc_update_irq(rtc->rtc_dev, 1, RTC_AF);
80
81 return IRQ_HANDLED;
82}
83
84static int st_rtc_read_time(struct device *dev, struct rtc_time *tm)
85{
86 struct st_rtc *rtc = dev_get_drvdata(dev);
87 unsigned long lpt_lsb, lpt_msb;
88 unsigned long long lpt;
89 unsigned long flags;
90
91 spin_lock_irqsave(&rtc->lock, flags);
92
93 do {
94 lpt_msb = readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF);
95 lpt_lsb = readl_relaxed(rtc->ioaddr + LPC_LPT_LSB_OFF);
96 } while (readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF) != lpt_msb);
97
98 spin_unlock_irqrestore(&rtc->lock, flags);
99
100 lpt = ((unsigned long long)lpt_msb << 32) | lpt_lsb;
101 do_div(lpt, rtc->clkrate);
102 rtc_time_to_tm(lpt, tm);
103
104 return 0;
105}
106
107static int st_rtc_set_time(struct device *dev, struct rtc_time *tm)
108{
109 struct st_rtc *rtc = dev_get_drvdata(dev);
110 unsigned long long lpt;
111 unsigned long secs, flags;
112 int ret;
113
114 ret = rtc_tm_to_time(tm, &secs);
115 if (ret)
116 return ret;
117
118 lpt = (unsigned long long)secs * rtc->clkrate;
119
120 spin_lock_irqsave(&rtc->lock, flags);
121
122 writel_relaxed(lpt >> 32, rtc->ioaddr + LPC_LPT_MSB_OFF);
123 writel_relaxed(lpt, rtc->ioaddr + LPC_LPT_LSB_OFF);
124 writel_relaxed(1, rtc->ioaddr + LPC_LPT_START_OFF);
125
126 spin_unlock_irqrestore(&rtc->lock, flags);
127
128 return 0;
129}
130
131static int st_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
132{
133 struct st_rtc *rtc = dev_get_drvdata(dev);
134 unsigned long flags;
135
136 spin_lock_irqsave(&rtc->lock, flags);
137
138 memcpy(wkalrm, &rtc->alarm, sizeof(struct rtc_wkalrm));
139
140 spin_unlock_irqrestore(&rtc->lock, flags);
141
142 return 0;
143}
144
145static int st_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
146{
147 struct st_rtc *rtc = dev_get_drvdata(dev);
148
149 if (enabled && !rtc->irq_enabled) {
150 enable_irq(rtc->irq);
151 rtc->irq_enabled = true;
152 } else if (!enabled && rtc->irq_enabled) {
153 disable_irq(rtc->irq);
154 rtc->irq_enabled = false;
155 }
156
157 return 0;
158}
159
160static int st_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
161{
162 struct st_rtc *rtc = dev_get_drvdata(dev);
163 struct rtc_time now;
164 unsigned long now_secs;
165 unsigned long alarm_secs;
166 unsigned long long lpa;
167
168 st_rtc_read_time(dev, &now);
169 rtc_tm_to_time(&now, &now_secs);
170 rtc_tm_to_time(&t->time, &alarm_secs);
171
172
173 if (now_secs > alarm_secs)
174 return -EINVAL;
175
176 memcpy(&rtc->alarm, t, sizeof(struct rtc_wkalrm));
177
178
179 alarm_secs -= now_secs;
180 lpa = (unsigned long long)alarm_secs * rtc->clkrate;
181
182 st_rtc_set_hw_alarm(rtc, lpa >> 32, lpa);
183 st_rtc_alarm_irq_enable(dev, t->enabled);
184
185 return 0;
186}
187
188static struct rtc_class_ops st_rtc_ops = {
189 .read_time = st_rtc_read_time,
190 .set_time = st_rtc_set_time,
191 .read_alarm = st_rtc_read_alarm,
192 .set_alarm = st_rtc_set_alarm,
193 .alarm_irq_enable = st_rtc_alarm_irq_enable,
194};
195
196static int st_rtc_probe(struct platform_device *pdev)
197{
198 struct device_node *np = pdev->dev.of_node;
199 struct st_rtc *rtc;
200 struct resource *res;
201 struct rtc_time tm_check;
202 uint32_t mode;
203 int ret = 0;
204
205 ret = of_property_read_u32(np, "st,lpc-mode", &mode);
206 if (ret) {
207 dev_err(&pdev->dev, "An LPC mode must be provided\n");
208 return -EINVAL;
209 }
210
211
212 if (mode != ST_LPC_MODE_RTC)
213 return -ENODEV;
214
215 rtc = devm_kzalloc(&pdev->dev, sizeof(struct st_rtc), GFP_KERNEL);
216 if (!rtc)
217 return -ENOMEM;
218
219 spin_lock_init(&rtc->lock);
220
221 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
222 rtc->ioaddr = devm_ioremap_resource(&pdev->dev, res);
223 if (IS_ERR(rtc->ioaddr))
224 return PTR_ERR(rtc->ioaddr);
225
226 rtc->irq = irq_of_parse_and_map(np, 0);
227 if (!rtc->irq) {
228 dev_err(&pdev->dev, "IRQ missing or invalid\n");
229 return -EINVAL;
230 }
231
232 ret = devm_request_irq(&pdev->dev, rtc->irq, st_rtc_handler, 0,
233 pdev->name, rtc);
234 if (ret) {
235 dev_err(&pdev->dev, "Failed to request irq %i\n", rtc->irq);
236 return ret;
237 }
238
239 enable_irq_wake(rtc->irq);
240 disable_irq(rtc->irq);
241
242 rtc->clk = clk_get(&pdev->dev, NULL);
243 if (IS_ERR(rtc->clk)) {
244 dev_err(&pdev->dev, "Unable to request clock\n");
245 return PTR_ERR(rtc->clk);
246 }
247
248 clk_prepare_enable(rtc->clk);
249
250 rtc->clkrate = clk_get_rate(rtc->clk);
251 if (!rtc->clkrate) {
252 dev_err(&pdev->dev, "Unable to fetch clock rate\n");
253 return -EINVAL;
254 }
255
256 device_set_wakeup_capable(&pdev->dev, 1);
257
258 platform_set_drvdata(pdev, rtc);
259
260
261
262
263
264
265
266 st_rtc_read_time(&pdev->dev, &tm_check);
267
268 if (tm_check.tm_year >= (2038 - 1900)) {
269 memset(&tm_check, 0, sizeof(tm_check));
270 tm_check.tm_year = 100;
271 tm_check.tm_mday = 1;
272 st_rtc_set_time(&pdev->dev, &tm_check);
273 }
274
275 rtc->rtc_dev = rtc_device_register("st-lpc-rtc", &pdev->dev,
276 &st_rtc_ops, THIS_MODULE);
277 if (IS_ERR(rtc->rtc_dev)) {
278 clk_disable_unprepare(rtc->clk);
279 return PTR_ERR(rtc->rtc_dev);
280 }
281
282 return 0;
283}
284
285static int st_rtc_remove(struct platform_device *pdev)
286{
287 struct st_rtc *rtc = platform_get_drvdata(pdev);
288
289 if (likely(rtc->rtc_dev))
290 rtc_device_unregister(rtc->rtc_dev);
291
292 return 0;
293}
294
295#ifdef CONFIG_PM_SLEEP
296static int st_rtc_suspend(struct device *dev)
297{
298 struct st_rtc *rtc = dev_get_drvdata(dev);
299
300 if (device_may_wakeup(dev))
301 return 0;
302
303 writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
304 writel_relaxed(0, rtc->ioaddr + LPC_LPA_START_OFF);
305 writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
306
307 return 0;
308}
309
310static int st_rtc_resume(struct device *dev)
311{
312 struct st_rtc *rtc = dev_get_drvdata(dev);
313
314 rtc_alarm_irq_enable(rtc->rtc_dev, 0);
315
316
317
318
319
320 memset(&rtc->alarm, 0, sizeof(struct rtc_wkalrm));
321
322 writel_relaxed(0, rtc->ioaddr + LPC_LPA_MSB_OFF);
323 writel_relaxed(0, rtc->ioaddr + LPC_LPA_LSB_OFF);
324 writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
325 writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
326 writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
327
328 return 0;
329}
330#endif
331
332static SIMPLE_DEV_PM_OPS(st_rtc_pm_ops, st_rtc_suspend, st_rtc_resume);
333
334static const struct of_device_id st_rtc_match[] = {
335 { .compatible = "st,stih407-lpc" },
336 {}
337};
338MODULE_DEVICE_TABLE(of, st_rtc_match);
339
340static struct platform_driver st_rtc_platform_driver = {
341 .driver = {
342 .name = "st-lpc-rtc",
343 .pm = &st_rtc_pm_ops,
344 .of_match_table = st_rtc_match,
345 },
346 .probe = st_rtc_probe,
347 .remove = st_rtc_remove,
348};
349
350module_platform_driver(st_rtc_platform_driver);
351
352MODULE_DESCRIPTION("STMicroelectronics LPC RTC driver");
353MODULE_AUTHOR("David Paris <david.paris@st.com>");
354MODULE_LICENSE("GPL");
355
