tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
60struct 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
69static 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
80static 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
93static int at32_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
94{
95 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
96
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);
102
103 return 0;
104}
105
106static int at32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
107{
108 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
109 unsigned long rtc_unix_time;
110 unsigned long alarm_unix_time;
111 int ret;
112
113 rtc_unix_time = rtc_readl(rtc, VAL);
114
115 ret = rtc_tm_to_time(&alrm->time, &alarm_unix_time);
116 if (ret)
117 return ret;
118
119 if (alarm_unix_time < rtc_unix_time)
120 return -EINVAL;
121
122 spin_lock_irq(&rtc->lock);
123 rtc->alarm_time = alarm_unix_time;
124 rtc_writel(rtc, TOP, rtc->alarm_time);
125 if (alrm->enabled)
126 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
127 | RTC_BIT(CTRL_TOPEN));
128 else
129 rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
130 & ~RTC_BIT(CTRL_TOPEN));
131 spin_unlock_irq(&rtc->lock);
132
133 return ret;
134}
135
136static int at32_rtc_ioctl(struct device *dev, unsigned int cmd,
137 unsigned long arg)
138{
139 struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
140 int ret = 0;
141
142 spin_lock_irq(&rtc->lock);
143
144 switch (cmd) {
145 case RTC_AIE_ON:
146 if (rtc_readl(rtc, VAL) > rtc->alarm_time) {
147 ret = -EINVAL;
148 break;
149 }
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));
154 break;
155 case RTC_AIE_OFF:
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));
160 break;
161 default:
162 ret = -ENOIOCTLCMD;
163 break;
164 }
165
166 spin_unlock_irq(&rtc->lock);
167
168 return ret;
169}
170
171static irqreturn_t at32_rtc_interrupt(int irq, void *dev_id)
172{
173 struct rtc_at32ap700x *rtc = (struct rtc_at32ap700x *)dev_id;
174 unsigned long isr = rtc_readl(rtc, ISR);
175 unsigned long events = 0;
176 int ret = IRQ_NONE;
177
178 spin_lock(&rtc->lock);
179
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);
188 ret = IRQ_HANDLED;
189 }
190
191 spin_unlock(&rtc->lock);
192
193 return ret;
194}
195
196static 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,
202};
203
204static int __init at32_rtc_probe(struct platform_device *pdev)
205{
206 struct resource *regs;
207 struct rtc_at32ap700x *rtc;
208 int irq;
209 int ret;
210
211 rtc = kzalloc(sizeof(struct rtc_at32ap700x), GFP_KERNEL);
212 if (!rtc) {
213 dev_dbg(&pdev->dev, "out of memory\n");
214 return -ENOMEM;
215 }
216
217 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
218 if (!regs) {
219 dev_dbg(&pdev->dev, "no mmio resource defined\n");
220 ret = -ENXIO;
221 goto out;
222 }
223
224 irq = platform_get_irq(pdev, 0);
225 if (irq <= 0) {
226 dev_dbg(&pdev->dev, "could not get irq\n");
227 ret = -ENXIO;
228 goto out;
229 }
230
231 rtc->irq = irq;
232 rtc->regs = ioremap(regs->start, regs->end - regs->start + 1);
233 if (!rtc->regs) {
234 ret = -ENOMEM;
235 dev_dbg(&pdev->dev, "could not map I/O memory\n");
236 goto out;
237 }
238 spin_lock_init(&rtc->lock);
239
240 /*
241 * Maybe init RTC: count from zero at 1 Hz, disable wrap irq.
242 *
243 * Do not reset VAL register, as it can hold an old time
244 * from last JTAG reset.
245 */
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)
250 | RTC_BIT(CTRL_EN));
251 }
252
253 ret = request_irq(irq, at32_rtc_interrupt, IRQF_SHARED, "rtc", rtc);
254 if (ret) {
255 dev_dbg(&pdev->dev, "could not request irq %d\n", irq);
256 goto out_iounmap;
257 }
258
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);
264 goto out_free_irq;
265 }
266
267 platform_set_drvdata(pdev, rtc);
268 device_init_wakeup(&pdev->dev, 1);
269
270 dev_info(&pdev->dev, "Atmel RTC for AT32AP700x at %08lx irq %ld\n",
271 (unsigned long)rtc->regs, rtc->irq);
272
273 return 0;
274
275out_free_irq:
276 free_irq(irq, rtc);
277out_iounmap:
278 iounmap(rtc->regs);
279out:
280 kfree(rtc);
281 return ret;
282}
283
284static int __exit at32_rtc_remove(struct platform_device *pdev)
285{
286 struct rtc_at32ap700x *rtc = platform_get_drvdata(pdev);
287
288 device_init_wakeup(&pdev->dev, 0);
289
290 free_irq(rtc->irq, rtc);
291 iounmap(rtc->regs);
292 rtc_device_unregister(rtc->rtc);
293 kfree(rtc);
294 platform_set_drvdata(pdev, NULL);
295
296 return 0;
297}
298
299MODULE_ALIAS("platform:at32ap700x_rtc");
300
301static struct platform_driver at32_rtc_driver = {
302 .remove = __exit_p(at32_rtc_remove),
303 .driver = {
304 .name = "at32ap700x_rtc",
305 .owner = THIS_MODULE,
306 },
307};
308
309static int __init at32_rtc_init(void)
310{
311 return platform_driver_probe(&at32_rtc_driver, at32_rtc_probe);
312}
313module_init(at32_rtc_init);
314
315static void __exit at32_rtc_exit(void)
316{
317 platform_driver_unregister(&at32_rtc_driver);
318}
319module_exit(at32_rtc_exit);
320
321MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
322MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");
323MODULE_LICENSE("GPL");