1 /*
2 * An RTC driver for the AVR32 AT32AP700x processor series.
3 *
4 * Copyright (C) 2007 Atmel Corporation
5 *
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.
9 */
10
11 #include <linux/module.h>
12 #include <linux/kernel.h>
13 #include <linux/platform_device.h>
14 #include <linux/rtc.h>
15 #include <linux/io.h>
16
17 /*
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
21 * much use.
22 *
23 * The alarm functionality is limited by the hardware, not supporting
24 * periodic interrupts.
25 */
26
27 #define RTC_CTRL 0x00
28 #define RTC_CTRL_EN 0
29 #define RTC_CTRL_PCLR 1
30 #define RTC_CTRL_TOPEN 2
31 #define RTC_CTRL_PSEL 8
32
33 #define RTC_VAL 0x04
34
35 #define RTC_TOP 0x08
36
37 #define RTC_IER 0x10
38 #define RTC_IER_TOPI 0
39
40 #define RTC_IDR 0x14
41 #define RTC_IDR_TOPI 0
42
43 #define RTC_IMR 0x18
44 #define RTC_IMR_TOPI 0
45
46 #define RTC_ISR 0x1c
47 #define RTC_ISR_TOPI 0
48
49 #define RTC_ICR 0x20
50 #define RTC_ICR_TOPI 0
51
52 #define RTC_BIT(name) (1 << RTC_##name)
53 #define RTC_BF(name, value) ((value) << RTC_##name)
54
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)
59
60 struct rtc_at32ap700x {
61 struct rtc_device *rtc;
62 void __iomem *regs;
63 unsigned long alarm_time;
64 unsigned long irq;
65 /* Protect against concurrent register access. */
66 spinlock_t lock;
67 };
68
69 static int at32_rtc_readtime(struct device *dev, struct rtc_time *tm)
70 {
71 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
72 unsigned long now;
73
74 now = rtc_readl(rtc, VAL);
75 rtc_time_to_tm(now, tm);
76
77 return 0;
78 }
79
80 static int at32_rtc_settime(struct device *dev, struct rtc_time *tm)
81 {
82 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
83 unsigned long now;
84 int ret;
85
86 ret = rtc_tm_to_time(tm, &now);
87 if (ret == 0)
88 rtc_writel(rtc, VAL, now);
89
90 return ret;
91 }
92
93 static int at32_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
94 {
95 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
96
97 rtc_time_to_tm(rtc->alarm_time, &alrm->time);
98 alrm->pending = rtc_readl(rtc, IMR) & RTC_BIT(IMR_TOPI) ? 1 : 0;
99
100 return 0;
101 }
102
103 static int at32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
104 {
105 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
106 unsigned long rtc_unix_time;
107 unsigned long alarm_unix_time;
108 int ret;
109
110 rtc_unix_time = rtc_readl(rtc, VAL);
111
112 ret = rtc_tm_to_time(&alrm->time, &alarm_unix_time);
113 if (ret)
114 return ret;
115
116 if (alarm_unix_time < rtc_unix_time)
117 return -EINVAL;
118
119 spin_lock_irq(&rtc->lock);
120 rtc->alarm_time = alarm_unix_time;
121 rtc_writel(rtc, TOP, rtc->alarm_time);
122 if (alrm->pending)
123 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
124 | RTC_BIT(CTRL_TOPEN));
125 else
126 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
127 & ~RTC_BIT(CTRL_TOPEN));
128 spin_unlock_irq(&rtc->lock);
129
130 return ret;
131 }
132
133 static int at32_rtc_ioctl(struct device *dev, unsigned int cmd,
134 unsigned long arg)
135 {
136 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
137 int ret = 0;
138
139 spin_lock_irq(&rtc->lock);
140
141 switch (cmd) {
142 case RTC_AIE_ON:
143 if (rtc_readl(rtc, VAL) > rtc->alarm_time) {
144 ret = -EINVAL;
145 break;
146 }
147 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
148 | RTC_BIT(CTRL_TOPEN));
149 rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
150 rtc_writel(rtc, IER, RTC_BIT(IER_TOPI));
151 break;
152 case RTC_AIE_OFF:
153 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
154 & ~RTC_BIT(CTRL_TOPEN));
155 rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
156 rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
157 break;
158 default:
159 ret = -ENOIOCTLCMD;
160 break;
161 }
162
163 spin_unlock_irq(&rtc->lock);
164
165 return ret;
166 }
167
168 static irqreturn_t at32_rtc_interrupt(int irq, void *dev_id)
169 {
170 struct rtc_at32ap700x *rtc = (struct rtc_at32ap700x *)dev_id;
171 unsigned long isr = rtc_readl(rtc, ISR);
172 unsigned long events = 0;
173 int ret = IRQ_NONE;
174
175 spin_lock(&rtc->lock);
176
177 if (isr & RTC_BIT(ISR_TOPI)) {
178 rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
179 rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
180 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
181 & ~RTC_BIT(CTRL_TOPEN));
182 rtc_writel(rtc, VAL, rtc->alarm_time);
183 events = RTC_AF | RTC_IRQF;
184 rtc_update_irq(rtc->rtc, 1, events);
185 ret = IRQ_HANDLED;
186 }
187
188 spin_unlock(&rtc->lock);
189
190 return ret;
191 }
192
193 static struct rtc_class_ops at32_rtc_ops = {
194 .ioctl = at32_rtc_ioctl,
195 .read_time = at32_rtc_readtime,
196 .set_time = at32_rtc_settime,
197 .read_alarm = at32_rtc_readalarm,
198 .set_alarm = at32_rtc_setalarm,
199 };
200
201 static int __init at32_rtc_probe(struct platform_device *pdev)
202 {
203 struct resource *regs;
204 struct rtc_at32ap700x *rtc;
205 int irq = -1;
206 int ret;
207
208 rtc = kzalloc(sizeof(struct rtc_at32ap700x), GFP_KERNEL);
209 if (!rtc) {
210 dev_dbg(&pdev->dev, "out of memory\n");
211 return -ENOMEM;
212 }
213
214 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
215 if (!regs) {
216 dev_dbg(&pdev->dev, "no mmio resource defined\n");
217 ret = -ENXIO;
218 goto out;
219 }
220
221 irq = platform_get_irq(pdev, 0);
222 if (irq < 0) {
223 dev_dbg(&pdev->dev, "could not get irq\n");
224 ret = -ENXIO;
225 goto out;
226 }
227
228 rtc->irq = irq;
229 rtc->regs = ioremap(regs->start, regs->end - regs->start + 1);
230 if (!rtc->regs) {
231 ret = -ENOMEM;
232 dev_dbg(&pdev->dev, "could not map I/O memory\n");
233 goto out;
234 }
235 spin_lock_init(&rtc->lock);
236
237 /*
238 * Maybe init RTC: count from zero at 1 Hz, disable wrap irq.
239 *
240 * Do not reset VAL register, as it can hold an old time
241 * from last JTAG reset.
242 */
243 if (!(rtc_readl(rtc, CTRL) & RTC_BIT(CTRL_EN))) {
244 rtc_writel(rtc, CTRL, RTC_BIT(CTRL_PCLR));
245 rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
246 rtc_writel(rtc, CTRL, RTC_BF(CTRL_PSEL, 0xe)
247 | RTC_BIT(CTRL_EN));
248 }
249
250 ret = request_irq(irq, at32_rtc_interrupt, IRQF_SHARED, "rtc", rtc);
251 if (ret) {
252 dev_dbg(&pdev->dev, "could not request irq %d\n", irq);
253 goto out_iounmap;
254 }
255
256 rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
257 &at32_rtc_ops, THIS_MODULE);
258 if (IS_ERR(rtc->rtc)) {
259 dev_dbg(&pdev->dev, "could not register rtc device\n");
260 ret = PTR_ERR(rtc->rtc);
261 goto out_free_irq;
262 }
263
264 platform_set_drvdata(pdev, rtc);
265
266 dev_info(&pdev->dev, "Atmel RTC for AT32AP700x at %08lx irq %ld\n",
267 (unsigned long)rtc->regs, rtc->irq);
268
269 return 0;
270
271 out_free_irq:
272 free_irq(irq, rtc);
273 out_iounmap:
274 iounmap(rtc->regs);
275 out:
276 kfree(rtc);
277 return ret;
278 }
279
280 static int __exit at32_rtc_remove(struct platform_device *pdev)
281 {
282 struct rtc_at32ap700x *rtc = platform_get_drvdata(pdev);
283
284 free_irq(rtc->irq, rtc);
285 iounmap(rtc->regs);
286 rtc_device_unregister(rtc->rtc);
287 kfree(rtc);
288 platform_set_drvdata(pdev, NULL);
289
290 return 0;
291 }
292
293 MODULE_ALIAS("platform:at32ap700x_rtc");
294
295 static struct platform_driver at32_rtc_driver = {
296 .remove = __exit_p(at32_rtc_remove),
297 .driver = {
298 .name = "at32ap700x_rtc",
299 .owner = THIS_MODULE,
300 },
301 };
302
303 static int __init at32_rtc_init(void)
304 {
305 return platform_driver_probe(&at32_rtc_driver, at32_rtc_probe);
306 }
307 module_init(at32_rtc_init);
308
309 static void __exit at32_rtc_exit(void)
310 {
311 platform_driver_unregister(&at32_rtc_driver);
312 }
313 module_exit(at32_rtc_exit);
314
315 MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
316 MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");
317 MODULE_LICENSE("GPL");
318
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