xref: /openbmc/linux/drivers/rtc/rtc-mv.c (revision b34e08d5)
1 /*
2  * Driver for the RTC in Marvell SoCs.
3  *
4  * This file is licensed under the terms of the GNU General Public
5  * License version 2.  This program is licensed "as is" without any
6  * warranty of any kind, whether express or implied.
7  */
8 
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/rtc.h>
12 #include <linux/bcd.h>
13 #include <linux/io.h>
14 #include <linux/platform_device.h>
15 #include <linux/of.h>
16 #include <linux/delay.h>
17 #include <linux/clk.h>
18 #include <linux/gfp.h>
19 #include <linux/module.h>
20 
21 
22 #define RTC_TIME_REG_OFFS	0
23 #define RTC_SECONDS_OFFS	0
24 #define RTC_MINUTES_OFFS	8
25 #define RTC_HOURS_OFFS		16
26 #define RTC_WDAY_OFFS		24
27 #define RTC_HOURS_12H_MODE		(1 << 22) /* 12 hours mode */
28 
29 #define RTC_DATE_REG_OFFS	4
30 #define RTC_MDAY_OFFS		0
31 #define RTC_MONTH_OFFS		8
32 #define RTC_YEAR_OFFS		16
33 
34 #define RTC_ALARM_TIME_REG_OFFS	8
35 #define RTC_ALARM_DATE_REG_OFFS	0xc
36 #define RTC_ALARM_VALID		(1 << 7)
37 
38 #define RTC_ALARM_INTERRUPT_MASK_REG_OFFS	0x10
39 #define RTC_ALARM_INTERRUPT_CASUE_REG_OFFS	0x14
40 
41 struct rtc_plat_data {
42 	struct rtc_device *rtc;
43 	void __iomem *ioaddr;
44 	int		irq;
45 	struct clk	*clk;
46 };
47 
48 static int mv_rtc_set_time(struct device *dev, struct rtc_time *tm)
49 {
50 	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
51 	void __iomem *ioaddr = pdata->ioaddr;
52 	u32	rtc_reg;
53 
54 	rtc_reg = (bin2bcd(tm->tm_sec) << RTC_SECONDS_OFFS) |
55 		(bin2bcd(tm->tm_min) << RTC_MINUTES_OFFS) |
56 		(bin2bcd(tm->tm_hour) << RTC_HOURS_OFFS) |
57 		(bin2bcd(tm->tm_wday) << RTC_WDAY_OFFS);
58 	writel(rtc_reg, ioaddr + RTC_TIME_REG_OFFS);
59 
60 	rtc_reg = (bin2bcd(tm->tm_mday) << RTC_MDAY_OFFS) |
61 		(bin2bcd(tm->tm_mon + 1) << RTC_MONTH_OFFS) |
62 		(bin2bcd(tm->tm_year % 100) << RTC_YEAR_OFFS);
63 	writel(rtc_reg, ioaddr + RTC_DATE_REG_OFFS);
64 
65 	return 0;
66 }
67 
68 static int mv_rtc_read_time(struct device *dev, struct rtc_time *tm)
69 {
70 	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
71 	void __iomem *ioaddr = pdata->ioaddr;
72 	u32	rtc_time, rtc_date;
73 	unsigned int year, month, day, hour, minute, second, wday;
74 
75 	rtc_time = readl(ioaddr + RTC_TIME_REG_OFFS);
76 	rtc_date = readl(ioaddr + RTC_DATE_REG_OFFS);
77 
78 	second = rtc_time & 0x7f;
79 	minute = (rtc_time >> RTC_MINUTES_OFFS) & 0x7f;
80 	hour = (rtc_time >> RTC_HOURS_OFFS) & 0x3f; /* assume 24 hours mode */
81 	wday = (rtc_time >> RTC_WDAY_OFFS) & 0x7;
82 
83 	day = rtc_date & 0x3f;
84 	month = (rtc_date >> RTC_MONTH_OFFS) & 0x3f;
85 	year = (rtc_date >> RTC_YEAR_OFFS) & 0xff;
86 
87 	tm->tm_sec = bcd2bin(second);
88 	tm->tm_min = bcd2bin(minute);
89 	tm->tm_hour = bcd2bin(hour);
90 	tm->tm_mday = bcd2bin(day);
91 	tm->tm_wday = bcd2bin(wday);
92 	tm->tm_mon = bcd2bin(month) - 1;
93 	/* hw counts from year 2000, but tm_year is relative to 1900 */
94 	tm->tm_year = bcd2bin(year) + 100;
95 
96 	return rtc_valid_tm(tm);
97 }
98 
99 static int mv_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm)
100 {
101 	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
102 	void __iomem *ioaddr = pdata->ioaddr;
103 	u32	rtc_time, rtc_date;
104 	unsigned int year, month, day, hour, minute, second, wday;
105 
106 	rtc_time = readl(ioaddr + RTC_ALARM_TIME_REG_OFFS);
107 	rtc_date = readl(ioaddr + RTC_ALARM_DATE_REG_OFFS);
108 
109 	second = rtc_time & 0x7f;
110 	minute = (rtc_time >> RTC_MINUTES_OFFS) & 0x7f;
111 	hour = (rtc_time >> RTC_HOURS_OFFS) & 0x3f; /* assume 24 hours mode */
112 	wday = (rtc_time >> RTC_WDAY_OFFS) & 0x7;
113 
114 	day = rtc_date & 0x3f;
115 	month = (rtc_date >> RTC_MONTH_OFFS) & 0x3f;
116 	year = (rtc_date >> RTC_YEAR_OFFS) & 0xff;
117 
118 	alm->time.tm_sec = bcd2bin(second);
119 	alm->time.tm_min = bcd2bin(minute);
120 	alm->time.tm_hour = bcd2bin(hour);
121 	alm->time.tm_mday = bcd2bin(day);
122 	alm->time.tm_wday = bcd2bin(wday);
123 	alm->time.tm_mon = bcd2bin(month) - 1;
124 	/* hw counts from year 2000, but tm_year is relative to 1900 */
125 	alm->time.tm_year = bcd2bin(year) + 100;
126 
127 	if (rtc_valid_tm(&alm->time) < 0) {
128 		dev_err(dev, "retrieved alarm date/time is not valid.\n");
129 		rtc_time_to_tm(0, &alm->time);
130 	}
131 
132 	alm->enabled = !!readl(ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
133 	return 0;
134 }
135 
136 static int mv_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm)
137 {
138 	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
139 	void __iomem *ioaddr = pdata->ioaddr;
140 	u32 rtc_reg = 0;
141 
142 	if (alm->time.tm_sec >= 0)
143 		rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_sec))
144 			<< RTC_SECONDS_OFFS;
145 	if (alm->time.tm_min >= 0)
146 		rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_min))
147 			<< RTC_MINUTES_OFFS;
148 	if (alm->time.tm_hour >= 0)
149 		rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_hour))
150 			<< RTC_HOURS_OFFS;
151 
152 	writel(rtc_reg, ioaddr + RTC_ALARM_TIME_REG_OFFS);
153 
154 	if (alm->time.tm_mday >= 0)
155 		rtc_reg = (RTC_ALARM_VALID | bin2bcd(alm->time.tm_mday))
156 			<< RTC_MDAY_OFFS;
157 	else
158 		rtc_reg = 0;
159 
160 	if (alm->time.tm_mon >= 0)
161 		rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_mon + 1))
162 			<< RTC_MONTH_OFFS;
163 
164 	if (alm->time.tm_year >= 0)
165 		rtc_reg |= (RTC_ALARM_VALID | bin2bcd(alm->time.tm_year % 100))
166 			<< RTC_YEAR_OFFS;
167 
168 	writel(rtc_reg, ioaddr + RTC_ALARM_DATE_REG_OFFS);
169 	writel(0, ioaddr + RTC_ALARM_INTERRUPT_CASUE_REG_OFFS);
170 	writel(alm->enabled ? 1 : 0,
171 	       ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
172 
173 	return 0;
174 }
175 
176 static int mv_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
177 {
178 	struct platform_device *pdev = to_platform_device(dev);
179 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
180 	void __iomem *ioaddr = pdata->ioaddr;
181 
182 	if (pdata->irq < 0)
183 		return -EINVAL; /* fall back into rtc-dev's emulation */
184 
185 	if (enabled)
186 		writel(1, ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
187 	else
188 		writel(0, ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
189 	return 0;
190 }
191 
192 static irqreturn_t mv_rtc_interrupt(int irq, void *data)
193 {
194 	struct rtc_plat_data *pdata = data;
195 	void __iomem *ioaddr = pdata->ioaddr;
196 
197 	/* alarm irq? */
198 	if (!readl(ioaddr + RTC_ALARM_INTERRUPT_CASUE_REG_OFFS))
199 		return IRQ_NONE;
200 
201 	/* clear interrupt */
202 	writel(0, ioaddr + RTC_ALARM_INTERRUPT_CASUE_REG_OFFS);
203 	rtc_update_irq(pdata->rtc, 1, RTC_IRQF | RTC_AF);
204 	return IRQ_HANDLED;
205 }
206 
207 static const struct rtc_class_ops mv_rtc_ops = {
208 	.read_time	= mv_rtc_read_time,
209 	.set_time	= mv_rtc_set_time,
210 };
211 
212 static const struct rtc_class_ops mv_rtc_alarm_ops = {
213 	.read_time	= mv_rtc_read_time,
214 	.set_time	= mv_rtc_set_time,
215 	.read_alarm	= mv_rtc_read_alarm,
216 	.set_alarm	= mv_rtc_set_alarm,
217 	.alarm_irq_enable = mv_rtc_alarm_irq_enable,
218 };
219 
220 static int __init mv_rtc_probe(struct platform_device *pdev)
221 {
222 	struct resource *res;
223 	struct rtc_plat_data *pdata;
224 	u32 rtc_time;
225 	u32 rtc_date;
226 	int ret = 0;
227 
228 	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
229 	if (!pdata)
230 		return -ENOMEM;
231 
232 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
233 	pdata->ioaddr = devm_ioremap_resource(&pdev->dev, res);
234 	if (IS_ERR(pdata->ioaddr))
235 		return PTR_ERR(pdata->ioaddr);
236 
237 	pdata->clk = devm_clk_get(&pdev->dev, NULL);
238 	/* Not all SoCs require a clock.*/
239 	if (!IS_ERR(pdata->clk))
240 		clk_prepare_enable(pdata->clk);
241 
242 	/* make sure the 24 hours mode is enabled */
243 	rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
244 	if (rtc_time & RTC_HOURS_12H_MODE) {
245 		dev_err(&pdev->dev, "24 Hours mode not supported.\n");
246 		ret = -EINVAL;
247 		goto out;
248 	}
249 
250 	/* make sure it is actually functional */
251 	if (rtc_time == 0x01000000) {
252 		ssleep(1);
253 		rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
254 		if (rtc_time == 0x01000000) {
255 			dev_err(&pdev->dev, "internal RTC not ticking\n");
256 			ret = -ENODEV;
257 			goto out;
258 		}
259 	}
260 
261 	/*
262 	 * A date after January 19th, 2038 does not fit on 32 bits and
263 	 * will confuse the kernel and userspace. Reset to a sane date
264 	 * (January 1st, 2013) if we're after 2038.
265 	 */
266 	rtc_date = readl(pdata->ioaddr + RTC_DATE_REG_OFFS);
267 	if (bcd2bin((rtc_date >> RTC_YEAR_OFFS) & 0xff) >= 38) {
268 		dev_info(&pdev->dev, "invalid RTC date, resetting to January 1st, 2013\n");
269 		writel(0x130101, pdata->ioaddr + RTC_DATE_REG_OFFS);
270 	}
271 
272 	pdata->irq = platform_get_irq(pdev, 0);
273 
274 	platform_set_drvdata(pdev, pdata);
275 
276 	if (pdata->irq >= 0) {
277 		device_init_wakeup(&pdev->dev, 1);
278 		pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
279 						 &mv_rtc_alarm_ops,
280 						 THIS_MODULE);
281 	} else {
282 		pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
283 						 &mv_rtc_ops, THIS_MODULE);
284 	}
285 	if (IS_ERR(pdata->rtc)) {
286 		ret = PTR_ERR(pdata->rtc);
287 		goto out;
288 	}
289 
290 	if (pdata->irq >= 0) {
291 		writel(0, pdata->ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
292 		if (devm_request_irq(&pdev->dev, pdata->irq, mv_rtc_interrupt,
293 				     IRQF_SHARED,
294 				     pdev->name, pdata) < 0) {
295 			dev_warn(&pdev->dev, "interrupt not available.\n");
296 			pdata->irq = -1;
297 		}
298 	}
299 
300 	return 0;
301 out:
302 	if (!IS_ERR(pdata->clk))
303 		clk_disable_unprepare(pdata->clk);
304 
305 	return ret;
306 }
307 
308 static int __exit mv_rtc_remove(struct platform_device *pdev)
309 {
310 	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
311 
312 	if (pdata->irq >= 0)
313 		device_init_wakeup(&pdev->dev, 0);
314 
315 	if (!IS_ERR(pdata->clk))
316 		clk_disable_unprepare(pdata->clk);
317 
318 	return 0;
319 }
320 
321 #ifdef CONFIG_OF
322 static struct of_device_id rtc_mv_of_match_table[] = {
323 	{ .compatible = "marvell,orion-rtc", },
324 	{}
325 };
326 #endif
327 
328 static struct platform_driver mv_rtc_driver = {
329 	.remove		= __exit_p(mv_rtc_remove),
330 	.driver		= {
331 		.name	= "rtc-mv",
332 		.owner	= THIS_MODULE,
333 		.of_match_table = of_match_ptr(rtc_mv_of_match_table),
334 	},
335 };
336 
337 module_platform_driver_probe(mv_rtc_driver, mv_rtc_probe);
338 
339 MODULE_AUTHOR("Saeed Bishara <saeed@marvell.com>");
340 MODULE_DESCRIPTION("Marvell RTC driver");
341 MODULE_LICENSE("GPL");
342 MODULE_ALIAS("platform:rtc-mv");
343