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13#include <linux/clk.h>
14#include <linux/delay.h>
15#include <linux/init.h>
16#include <linux/io.h>
17#include <linux/irq.h>
18#include <linux/kernel.h>
19#include <linux/module.h>
20#include <linux/of.h>
21#include <linux/of_irq.h>
22#include <linux/platform_device.h>
23#include <linux/rtc.h>
24
25#include <dt-bindings/mfd/st-lpc.h>
26
27
28#define LPC_LPT_LSB_OFF 0x400
29#define LPC_LPT_MSB_OFF 0x404
30#define LPC_LPT_START_OFF 0x408
31
32
33#define LPC_LPA_LSB_OFF 0x410
34#define LPC_LPA_MSB_OFF 0x414
35#define LPC_LPA_START_OFF 0x418
36
37
38#define LPC_WDT_OFF 0x510
39#define LPC_WDT_FLAG_OFF 0x514
40
41struct st_rtc {
42 struct rtc_device *rtc_dev;
43 struct rtc_wkalrm alarm;
44 struct clk *clk;
45 unsigned long clkrate;
46 void __iomem *ioaddr;
47 bool irq_enabled:1;
48 spinlock_t lock;
49 short irq;
50};
51
52static void st_rtc_set_hw_alarm(struct st_rtc *rtc,
53 unsigned long msb, unsigned long lsb)
54{
55 unsigned long flags;
56
57 spin_lock_irqsave(&rtc->lock, flags);
58
59 writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
60
61 writel_relaxed(msb, rtc->ioaddr + LPC_LPA_MSB_OFF);
62 writel_relaxed(lsb, rtc->ioaddr + LPC_LPA_LSB_OFF);
63 writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
64
65 writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
66
67 spin_unlock_irqrestore(&rtc->lock, flags);
68}
69
70static irqreturn_t st_rtc_handler(int this_irq, void *data)
71{
72 struct st_rtc *rtc = (struct st_rtc *)data;
73
74 rtc_update_irq(rtc->rtc_dev, 1, RTC_AF);
75
76 return IRQ_HANDLED;
77}
78
79static int st_rtc_read_time(struct device *dev, struct rtc_time *tm)
80{
81 struct st_rtc *rtc = dev_get_drvdata(dev);
82 unsigned long lpt_lsb, lpt_msb;
83 unsigned long long lpt;
84 unsigned long flags;
85
86 spin_lock_irqsave(&rtc->lock, flags);
87
88 do {
89 lpt_msb = readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF);
90 lpt_lsb = readl_relaxed(rtc->ioaddr + LPC_LPT_LSB_OFF);
91 } while (readl_relaxed(rtc->ioaddr + LPC_LPT_MSB_OFF) != lpt_msb);
92
93 spin_unlock_irqrestore(&rtc->lock, flags);
94
95 lpt = ((unsigned long long)lpt_msb << 32) | lpt_lsb;
96 do_div(lpt, rtc->clkrate);
97 rtc_time64_to_tm(lpt, tm);
98
99 return 0;
100}
101
102static int st_rtc_set_time(struct device *dev, struct rtc_time *tm)
103{
104 struct st_rtc *rtc = dev_get_drvdata(dev);
105 unsigned long long lpt, secs;
106 unsigned long flags;
107
108 secs = rtc_tm_to_time64(tm);
109
110 lpt = (unsigned long long)secs * rtc->clkrate;
111
112 spin_lock_irqsave(&rtc->lock, flags);
113
114 writel_relaxed(lpt >> 32, rtc->ioaddr + LPC_LPT_MSB_OFF);
115 writel_relaxed(lpt, rtc->ioaddr + LPC_LPT_LSB_OFF);
116 writel_relaxed(1, rtc->ioaddr + LPC_LPT_START_OFF);
117
118 spin_unlock_irqrestore(&rtc->lock, flags);
119
120 return 0;
121}
122
123static int st_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
124{
125 struct st_rtc *rtc = dev_get_drvdata(dev);
126 unsigned long flags;
127
128 spin_lock_irqsave(&rtc->lock, flags);
129
130 memcpy(wkalrm, &rtc->alarm, sizeof(struct rtc_wkalrm));
131
132 spin_unlock_irqrestore(&rtc->lock, flags);
133
134 return 0;
135}
136
137static int st_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
138{
139 struct st_rtc *rtc = dev_get_drvdata(dev);
140
141 if (enabled && !rtc->irq_enabled) {
142 enable_irq(rtc->irq);
143 rtc->irq_enabled = true;
144 } else if (!enabled && rtc->irq_enabled) {
145 disable_irq(rtc->irq);
146 rtc->irq_enabled = false;
147 }
148
149 return 0;
150}
151
152static int st_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *t)
153{
154 struct st_rtc *rtc = dev_get_drvdata(dev);
155 struct rtc_time now;
156 unsigned long long now_secs;
157 unsigned long long alarm_secs;
158 unsigned long long lpa;
159
160 st_rtc_read_time(dev, &now);
161 now_secs = rtc_tm_to_time64(&now);
162 alarm_secs = rtc_tm_to_time64(&t->time);
163
164 memcpy(&rtc->alarm, t, sizeof(struct rtc_wkalrm));
165
166
167 alarm_secs -= now_secs;
168 lpa = (unsigned long long)alarm_secs * rtc->clkrate;
169
170 st_rtc_set_hw_alarm(rtc, lpa >> 32, lpa);
171 st_rtc_alarm_irq_enable(dev, t->enabled);
172
173 return 0;
174}
175
176static struct rtc_class_ops st_rtc_ops = {
177 .read_time = st_rtc_read_time,
178 .set_time = st_rtc_set_time,
179 .read_alarm = st_rtc_read_alarm,
180 .set_alarm = st_rtc_set_alarm,
181 .alarm_irq_enable = st_rtc_alarm_irq_enable,
182};
183
184static int st_rtc_probe(struct platform_device *pdev)
185{
186 struct device_node *np = pdev->dev.of_node;
187 struct st_rtc *rtc;
188 uint32_t mode;
189 int ret = 0;
190
191 ret = of_property_read_u32(np, "st,lpc-mode", &mode);
192 if (ret) {
193 dev_err(&pdev->dev, "An LPC mode must be provided\n");
194 return -EINVAL;
195 }
196
197
198 if (mode != ST_LPC_MODE_RTC)
199 return -ENODEV;
200
201 rtc = devm_kzalloc(&pdev->dev, sizeof(struct st_rtc), GFP_KERNEL);
202 if (!rtc)
203 return -ENOMEM;
204
205 rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
206 if (IS_ERR(rtc->rtc_dev))
207 return PTR_ERR(rtc->rtc_dev);
208
209 spin_lock_init(&rtc->lock);
210
211 rtc->ioaddr = devm_platform_ioremap_resource(pdev, 0);
212 if (IS_ERR(rtc->ioaddr))
213 return PTR_ERR(rtc->ioaddr);
214
215 rtc->irq = irq_of_parse_and_map(np, 0);
216 if (!rtc->irq) {
217 dev_err(&pdev->dev, "IRQ missing or invalid\n");
218 return -EINVAL;
219 }
220
221 ret = devm_request_irq(&pdev->dev, rtc->irq, st_rtc_handler, 0,
222 pdev->name, rtc);
223 if (ret) {
224 dev_err(&pdev->dev, "Failed to request irq %i\n", rtc->irq);
225 return ret;
226 }
227
228 enable_irq_wake(rtc->irq);
229 disable_irq(rtc->irq);
230
231 rtc->clk = clk_get(&pdev->dev, NULL);
232 if (IS_ERR(rtc->clk)) {
233 dev_err(&pdev->dev, "Unable to request clock\n");
234 return PTR_ERR(rtc->clk);
235 }
236
237 clk_prepare_enable(rtc->clk);
238
239 rtc->clkrate = clk_get_rate(rtc->clk);
240 if (!rtc->clkrate) {
241 dev_err(&pdev->dev, "Unable to fetch clock rate\n");
242 return -EINVAL;
243 }
244
245 device_set_wakeup_capable(&pdev->dev, 1);
246
247 platform_set_drvdata(pdev, rtc);
248
249 rtc->rtc_dev->ops = &st_rtc_ops;
250 rtc->rtc_dev->range_max = U64_MAX;
251 do_div(rtc->rtc_dev->range_max, rtc->clkrate);
252
253 ret = rtc_register_device(rtc->rtc_dev);
254 if (ret) {
255 clk_disable_unprepare(rtc->clk);
256 return ret;
257 }
258
259 return 0;
260}
261
262#ifdef CONFIG_PM_SLEEP
263static int st_rtc_suspend(struct device *dev)
264{
265 struct st_rtc *rtc = dev_get_drvdata(dev);
266
267 if (device_may_wakeup(dev))
268 return 0;
269
270 writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
271 writel_relaxed(0, rtc->ioaddr + LPC_LPA_START_OFF);
272 writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
273
274 return 0;
275}
276
277static int st_rtc_resume(struct device *dev)
278{
279 struct st_rtc *rtc = dev_get_drvdata(dev);
280
281 rtc_alarm_irq_enable(rtc->rtc_dev, 0);
282
283
284
285
286
287 memset(&rtc->alarm, 0, sizeof(struct rtc_wkalrm));
288
289 writel_relaxed(0, rtc->ioaddr + LPC_LPA_MSB_OFF);
290 writel_relaxed(0, rtc->ioaddr + LPC_LPA_LSB_OFF);
291 writel_relaxed(1, rtc->ioaddr + LPC_WDT_OFF);
292 writel_relaxed(1, rtc->ioaddr + LPC_LPA_START_OFF);
293 writel_relaxed(0, rtc->ioaddr + LPC_WDT_OFF);
294
295 return 0;
296}
297#endif
298
299static SIMPLE_DEV_PM_OPS(st_rtc_pm_ops, st_rtc_suspend, st_rtc_resume);
300
301static const struct of_device_id st_rtc_match[] = {
302 { .compatible = "st,stih407-lpc" },
303 {}
304};
305MODULE_DEVICE_TABLE(of, st_rtc_match);
306
307static struct platform_driver st_rtc_platform_driver = {
308 .driver = {
309 .name = "st-lpc-rtc",
310 .pm = &st_rtc_pm_ops,
311 .of_match_table = st_rtc_match,
312 },
313 .probe = st_rtc_probe,
314};
315
316module_platform_driver(st_rtc_platform_driver);
317
318MODULE_DESCRIPTION("STMicroelectronics LPC RTC driver");
319MODULE_AUTHOR("David Paris <david.paris@st.com>");
320MODULE_LICENSE("GPL");
321
