2 * An RTC driver for the AVR32 AT32AP700x processor series.
4 * Copyright (C) 2007 Atmel Corporation
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
11 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/platform_device.h>
14 #include <linux/rtc.h>
18 * This is a bare-bones RTC. It runs during most system sleep states, but has
19 * no battery backup and gets reset during system restart. It must be
20 * initialized from an external clock (network, I2C, etc) before it can be of
23 * The alarm functionality is limited by the hardware, not supporting
24 * periodic interrupts.
29 #define RTC_CTRL_PCLR 1
30 #define RTC_CTRL_TOPEN 2
31 #define RTC_CTRL_PSEL 8
38 #define RTC_IER_TOPI 0
41 #define RTC_IDR_TOPI 0
44 #define RTC_IMR_TOPI 0
47 #define RTC_ISR_TOPI 0
50 #define RTC_ICR_TOPI 0
52 #define RTC_BIT(name) (1 << RTC_##name)
53 #define RTC_BF(name, value) ((value) << RTC_##name)
55 #define rtc_readl(dev, reg) \
56 __raw_readl((dev)->regs + RTC_##reg)
57 #define rtc_writel(dev, reg, value) \
58 __raw_writel((value), (dev)->regs + RTC_##reg)
60 struct rtc_at32ap700x {
61 struct rtc_device *rtc;
63 unsigned long alarm_time;
65 /* Protect against concurrent register access. */
69 static int at32_rtc_readtime(struct device *dev, struct rtc_time *tm)
71 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
74 now = rtc_readl(rtc, VAL);
75 rtc_time_to_tm(now, tm);
80 static int at32_rtc_settime(struct device *dev, struct rtc_time *tm)
82 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
86 ret = rtc_tm_to_time(tm, &now);
88 rtc_writel(rtc, VAL, now);
93 static int at32_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
95 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
97 spin_lock_irq(&rtc->lock);
98 rtc_time_to_tm(rtc->alarm_time, &alrm->time);
99 alrm->enabled = rtc_readl(rtc, IMR) & RTC_BIT(IMR_TOPI) ? 1 : 0;
100 alrm->pending = rtc_readl(rtc, ISR) & RTC_BIT(ISR_TOPI) ? 1 : 0;
101 spin_unlock_irq(&rtc->lock);
106 static int at32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
108 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
109 unsigned long rtc_unix_time;
110 unsigned long alarm_unix_time;
113 rtc_unix_time = rtc_readl(rtc, VAL);
115 ret = rtc_tm_to_time(&alrm->time, &alarm_unix_time);
119 if (alarm_unix_time < rtc_unix_time)
122 spin_lock_irq(&rtc->lock);
123 rtc->alarm_time = alarm_unix_time;
124 rtc_writel(rtc, TOP, rtc->alarm_time);
126 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
127 | RTC_BIT(CTRL_TOPEN));
129 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
130 & ~RTC_BIT(CTRL_TOPEN));
131 spin_unlock_irq(&rtc->lock);
136 static int at32_rtc_ioctl(struct device *dev, unsigned int cmd,
139 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
142 spin_lock_irq(&rtc->lock);
146 if (rtc_readl(rtc, VAL) > rtc->alarm_time) {
150 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
151 | RTC_BIT(CTRL_TOPEN));
152 rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
153 rtc_writel(rtc, IER, RTC_BIT(IER_TOPI));
156 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
157 & ~RTC_BIT(CTRL_TOPEN));
158 rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
159 rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
166 spin_unlock_irq(&rtc->lock);
171 static irqreturn_t at32_rtc_interrupt(int irq, void *dev_id)
173 struct rtc_at32ap700x *rtc = (struct rtc_at32ap700x *)dev_id;
174 unsigned long isr = rtc_readl(rtc, ISR);
175 unsigned long events = 0;
178 spin_lock(&rtc->lock);
180 if (isr & RTC_BIT(ISR_TOPI)) {
181 rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
182 rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
183 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
184 & ~RTC_BIT(CTRL_TOPEN));
185 rtc_writel(rtc, VAL, rtc->alarm_time);
186 events = RTC_AF | RTC_IRQF;
187 rtc_update_irq(rtc->rtc, 1, events);
191 spin_unlock(&rtc->lock);
196 static struct rtc_class_ops at32_rtc_ops = {
197 .ioctl = at32_rtc_ioctl,
198 .read_time = at32_rtc_readtime,
199 .set_time = at32_rtc_settime,
200 .read_alarm = at32_rtc_readalarm,
201 .set_alarm = at32_rtc_setalarm,
204 static int __init at32_rtc_probe(struct platform_device *pdev)
206 struct resource *regs;
207 struct rtc_at32ap700x *rtc;
211 rtc = kzalloc(sizeof(struct rtc_at32ap700x), GFP_KERNEL);
213 dev_dbg(&pdev->dev, "out of memory\n");
217 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
219 dev_dbg(&pdev->dev, "no mmio resource defined\n");
224 irq = platform_get_irq(pdev, 0);
226 dev_dbg(&pdev->dev, "could not get irq\n");
232 rtc->regs = ioremap(regs->start, regs->end - regs->start + 1);
235 dev_dbg(&pdev->dev, "could not map I/O memory\n");
238 spin_lock_init(&rtc->lock);
241 * Maybe init RTC: count from zero at 1 Hz, disable wrap irq.
243 * Do not reset VAL register, as it can hold an old time
244 * from last JTAG reset.
246 if (!(rtc_readl(rtc, CTRL) & RTC_BIT(CTRL_EN))) {
247 rtc_writel(rtc, CTRL, RTC_BIT(CTRL_PCLR));
248 rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
249 rtc_writel(rtc, CTRL, RTC_BF(CTRL_PSEL, 0xe)
253 ret = request_irq(irq, at32_rtc_interrupt, IRQF_SHARED, "rtc", rtc);
255 dev_dbg(&pdev->dev, "could not request irq %d\n", irq);
259 rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
260 &at32_rtc_ops, THIS_MODULE);
261 if (IS_ERR(rtc->rtc)) {
262 dev_dbg(&pdev->dev, "could not register rtc device\n");
263 ret = PTR_ERR(rtc->rtc);
267 platform_set_drvdata(pdev, rtc);
268 device_init_wakeup(&pdev->dev, 1);
270 dev_info(&pdev->dev, "Atmel RTC for AT32AP700x at %08lx irq %ld\n",
271 (unsigned long)rtc->regs, rtc->irq);
284 static int __exit at32_rtc_remove(struct platform_device *pdev)
286 struct rtc_at32ap700x *rtc = platform_get_drvdata(pdev);
288 device_init_wakeup(&pdev->dev, 0);
290 free_irq(rtc->irq, rtc);
292 rtc_device_unregister(rtc->rtc);
294 platform_set_drvdata(pdev, NULL);
299 MODULE_ALIAS("platform:at32ap700x_rtc");
301 static struct platform_driver at32_rtc_driver = {
302 .remove = __exit_p(at32_rtc_remove),
304 .name = "at32ap700x_rtc",
305 .owner = THIS_MODULE,
309 static int __init at32_rtc_init(void)
311 return platform_driver_probe(&at32_rtc_driver, at32_rtc_probe);
313 module_init(at32_rtc_init);
315 static void __exit at32_rtc_exit(void)
317 platform_driver_unregister(&at32_rtc_driver);
319 module_exit(at32_rtc_exit);
321 MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
322 MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");
323 MODULE_LICENSE("GPL");