Root/drivers/rtc/rtc-at32ap700x.c

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/slab.h>
15#include <linux/rtc.h>
16#include <linux/io.h>
17
18/*
19 * This is a bare-bones RTC. It runs during most system sleep states, but has
20 * no battery backup and gets reset during system restart. It must be
21 * initialized from an external clock (network, I2C, etc) before it can be of
22 * much use.
23 *
24 * The alarm functionality is limited by the hardware, not supporting
25 * periodic interrupts.
26 */
27
28#define RTC_CTRL 0x00
29#define RTC_CTRL_EN 0
30#define RTC_CTRL_PCLR 1
31#define RTC_CTRL_TOPEN 2
32#define RTC_CTRL_PSEL 8
33
34#define RTC_VAL 0x04
35
36#define RTC_TOP 0x08
37
38#define RTC_IER 0x10
39#define RTC_IER_TOPI 0
40
41#define RTC_IDR 0x14
42#define RTC_IDR_TOPI 0
43
44#define RTC_IMR 0x18
45#define RTC_IMR_TOPI 0
46
47#define RTC_ISR 0x1c
48#define RTC_ISR_TOPI 0
49
50#define RTC_ICR 0x20
51#define RTC_ICR_TOPI 0
52
53#define RTC_BIT(name) (1 << RTC_##name)
54#define RTC_BF(name, value) ((value) << RTC_##name)
55
56#define rtc_readl(dev, reg) \
57    __raw_readl((dev)->regs + RTC_##reg)
58#define rtc_writel(dev, reg, value) \
59    __raw_writel((value), (dev)->regs + RTC_##reg)
60
61struct rtc_at32ap700x {
62    struct rtc_device *rtc;
63    void __iomem *regs;
64    unsigned long alarm_time;
65    unsigned long irq;
66    /* Protect against concurrent register access. */
67    spinlock_t lock;
68};
69
70static int at32_rtc_readtime(struct device *dev, struct rtc_time *tm)
71{
72    struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
73    unsigned long now;
74
75    now = rtc_readl(rtc, VAL);
76    rtc_time_to_tm(now, tm);
77
78    return 0;
79}
80
81static int at32_rtc_settime(struct device *dev, struct rtc_time *tm)
82{
83    struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
84    unsigned long now;
85    int ret;
86
87    ret = rtc_tm_to_time(tm, &now);
88    if (ret == 0)
89        rtc_writel(rtc, VAL, now);
90
91    return ret;
92}
93
94static int at32_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
95{
96    struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
97
98    spin_lock_irq(&rtc->lock);
99    rtc_time_to_tm(rtc->alarm_time, &alrm->time);
100    alrm->enabled = rtc_readl(rtc, IMR) & RTC_BIT(IMR_TOPI) ? 1 : 0;
101    alrm->pending = rtc_readl(rtc, ISR) & RTC_BIT(ISR_TOPI) ? 1 : 0;
102    spin_unlock_irq(&rtc->lock);
103
104    return 0;
105}
106
107static int at32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
108{
109    struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
110    unsigned long rtc_unix_time;
111    unsigned long alarm_unix_time;
112    int ret;
113
114    rtc_unix_time = rtc_readl(rtc, VAL);
115
116    ret = rtc_tm_to_time(&alrm->time, &alarm_unix_time);
117    if (ret)
118        return ret;
119
120    if (alarm_unix_time < rtc_unix_time)
121        return -EINVAL;
122
123    spin_lock_irq(&rtc->lock);
124    rtc->alarm_time = alarm_unix_time;
125    rtc_writel(rtc, TOP, rtc->alarm_time);
126    if (alrm->enabled)
127        rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
128                | RTC_BIT(CTRL_TOPEN));
129    else
130        rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
131                & ~RTC_BIT(CTRL_TOPEN));
132    spin_unlock_irq(&rtc->lock);
133
134    return ret;
135}
136
137static int at32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
138{
139    struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
140    int ret = 0;
141
142    spin_lock_irq(&rtc->lock);
143
144    if(enabled) {
145        if (rtc_readl(rtc, VAL) > rtc->alarm_time) {
146            ret = -EINVAL;
147            goto out;
148        }
149        rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
150                | RTC_BIT(CTRL_TOPEN));
151        rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
152        rtc_writel(rtc, IER, RTC_BIT(IER_TOPI));
153    } else {
154        rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
155                & ~RTC_BIT(CTRL_TOPEN));
156        rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
157        rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
158    }
159out:
160    spin_unlock_irq(&rtc->lock);
161
162    return ret;
163}
164
165static irqreturn_t at32_rtc_interrupt(int irq, void *dev_id)
166{
167    struct rtc_at32ap700x *rtc = (struct rtc_at32ap700x *)dev_id;
168    unsigned long isr = rtc_readl(rtc, ISR);
169    unsigned long events = 0;
170    int ret = IRQ_NONE;
171
172    spin_lock(&rtc->lock);
173
174    if (isr & RTC_BIT(ISR_TOPI)) {
175        rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
176        rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
177        rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
178                & ~RTC_BIT(CTRL_TOPEN));
179        rtc_writel(rtc, VAL, rtc->alarm_time);
180        events = RTC_AF | RTC_IRQF;
181        rtc_update_irq(rtc->rtc, 1, events);
182        ret = IRQ_HANDLED;
183    }
184
185    spin_unlock(&rtc->lock);
186
187    return ret;
188}
189
190static struct rtc_class_ops at32_rtc_ops = {
191    .read_time = at32_rtc_readtime,
192    .set_time = at32_rtc_settime,
193    .read_alarm = at32_rtc_readalarm,
194    .set_alarm = at32_rtc_setalarm,
195    .alarm_irq_enable = at32_rtc_alarm_irq_enable,
196};
197
198static int __init at32_rtc_probe(struct platform_device *pdev)
199{
200    struct resource *regs;
201    struct rtc_at32ap700x *rtc;
202    int irq;
203    int ret;
204
205    rtc = kzalloc(sizeof(struct rtc_at32ap700x), GFP_KERNEL);
206    if (!rtc) {
207        dev_dbg(&pdev->dev, "out of memory\n");
208        return -ENOMEM;
209    }
210
211    regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
212    if (!regs) {
213        dev_dbg(&pdev->dev, "no mmio resource defined\n");
214        ret = -ENXIO;
215        goto out;
216    }
217
218    irq = platform_get_irq(pdev, 0);
219    if (irq <= 0) {
220        dev_dbg(&pdev->dev, "could not get irq\n");
221        ret = -ENXIO;
222        goto out;
223    }
224
225    rtc->irq = irq;
226    rtc->regs = ioremap(regs->start, resource_size(regs));
227    if (!rtc->regs) {
228        ret = -ENOMEM;
229        dev_dbg(&pdev->dev, "could not map I/O memory\n");
230        goto out;
231    }
232    spin_lock_init(&rtc->lock);
233
234    /*
235     * Maybe init RTC: count from zero at 1 Hz, disable wrap irq.
236     *
237     * Do not reset VAL register, as it can hold an old time
238     * from last JTAG reset.
239     */
240    if (!(rtc_readl(rtc, CTRL) & RTC_BIT(CTRL_EN))) {
241        rtc_writel(rtc, CTRL, RTC_BIT(CTRL_PCLR));
242        rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
243        rtc_writel(rtc, CTRL, RTC_BF(CTRL_PSEL, 0xe)
244                | RTC_BIT(CTRL_EN));
245    }
246
247    ret = request_irq(irq, at32_rtc_interrupt, IRQF_SHARED, "rtc", rtc);
248    if (ret) {
249        dev_dbg(&pdev->dev, "could not request irq %d\n", irq);
250        goto out_iounmap;
251    }
252
253    platform_set_drvdata(pdev, rtc);
254
255    rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
256                &at32_rtc_ops, THIS_MODULE);
257    if (IS_ERR(rtc->rtc)) {
258        dev_dbg(&pdev->dev, "could not register rtc device\n");
259        ret = PTR_ERR(rtc->rtc);
260        goto out_free_irq;
261    }
262
263    device_init_wakeup(&pdev->dev, 1);
264
265    dev_info(&pdev->dev, "Atmel RTC for AT32AP700x at %08lx irq %ld\n",
266            (unsigned long)rtc->regs, rtc->irq);
267
268    return 0;
269
270out_free_irq:
271    platform_set_drvdata(pdev, NULL);
272    free_irq(irq, rtc);
273out_iounmap:
274    iounmap(rtc->regs);
275out:
276    kfree(rtc);
277    return ret;
278}
279
280static int __exit at32_rtc_remove(struct platform_device *pdev)
281{
282    struct rtc_at32ap700x *rtc = platform_get_drvdata(pdev);
283
284    device_init_wakeup(&pdev->dev, 0);
285
286    free_irq(rtc->irq, rtc);
287    iounmap(rtc->regs);
288    rtc_device_unregister(rtc->rtc);
289    kfree(rtc);
290    platform_set_drvdata(pdev, NULL);
291
292    return 0;
293}
294
295MODULE_ALIAS("platform:at32ap700x_rtc");
296
297static struct platform_driver at32_rtc_driver = {
298    .remove = __exit_p(at32_rtc_remove),
299    .driver = {
300        .name = "at32ap700x_rtc",
301        .owner = THIS_MODULE,
302    },
303};
304
305static int __init at32_rtc_init(void)
306{
307    return platform_driver_probe(&at32_rtc_driver, at32_rtc_probe);
308}
309module_init(at32_rtc_init);
310
311static void __exit at32_rtc_exit(void)
312{
313    platform_driver_unregister(&at32_rtc_driver);
314}
315module_exit(at32_rtc_exit);
316
317MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
318MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");
319MODULE_LICENSE("GPL");
320

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