Merge branch 'omap-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux-2.6.git] / drivers / rtc / rtc-coh901331.c
1 /*
2  * Copyright (C) 2007-2009 ST-Ericsson AB
3  * License terms: GNU General Public License (GPL) version 2
4  * Real Time Clock interface for ST-Ericsson AB COH 901 331 RTC.
5  * Author: Linus Walleij <linus.walleij@stericsson.com>
6  * Based on rtc-pl031.c by Deepak Saxena <dsaxena@plexity.net>
7  * Copyright 2006 (c) MontaVista Software, Inc.
8  */
9 #include <linux/init.h>
10 #include <linux/module.h>
11 #include <linux/rtc.h>
12 #include <linux/clk.h>
13 #include <linux/interrupt.h>
14 #include <linux/pm.h>
15 #include <linux/platform_device.h>
16 #include <linux/io.h>
17
18 /*
19  * Registers in the COH 901 331
20  */
21 /* Alarm value 32bit (R/W) */
22 #define COH901331_ALARM         0x00U
23 /* Used to set current time 32bit (R/W) */
24 #define COH901331_SET_TIME      0x04U
25 /* Indication if current time is valid 32bit (R/-) */
26 #define COH901331_VALID         0x08U
27 /* Read the current time 32bit (R/-) */
28 #define COH901331_CUR_TIME      0x0cU
29 /* Event register for the "alarm" interrupt */
30 #define COH901331_IRQ_EVENT     0x10U
31 /* Mask register for the "alarm" interrupt */
32 #define COH901331_IRQ_MASK      0x14U
33 /* Force register for the "alarm" interrupt */
34 #define COH901331_IRQ_FORCE     0x18U
35
36 /*
37  * Reference to RTC block clock
38  * Notice that the frequent clk_enable()/clk_disable() on this
39  * clock is mainly to be able to turn on/off other clocks in the
40  * hierarchy as needed, the RTC clock is always on anyway.
41  */
42 struct coh901331_port {
43         struct rtc_device *rtc;
44         struct clk *clk;
45         u32 phybase;
46         u32 physize;
47         void __iomem *virtbase;
48         int irq;
49 #ifdef CONFIG_PM
50         u32 irqmaskstore;
51 #endif
52 };
53
54 static irqreturn_t coh901331_interrupt(int irq, void *data)
55 {
56         struct coh901331_port *rtap = data;
57
58         clk_enable(rtap->clk);
59         /* Ack IRQ */
60         writel(1, rtap->virtbase + COH901331_IRQ_EVENT);
61         /*
62          * Disable the interrupt. This is necessary because
63          * the RTC lives on a lower-clocked line and will
64          * not release the IRQ line until after a few (slower)
65          * clock cycles. The interrupt will be re-enabled when
66          * a new alarm is set anyway.
67          */
68         writel(0, rtap->virtbase + COH901331_IRQ_MASK);
69         clk_disable(rtap->clk);
70
71         /* Set alarm flag */
72         rtc_update_irq(rtap->rtc, 1, RTC_AF);
73
74         return IRQ_HANDLED;
75 }
76
77 static int coh901331_read_time(struct device *dev, struct rtc_time *tm)
78 {
79         struct coh901331_port *rtap = dev_get_drvdata(dev);
80
81         clk_enable(rtap->clk);
82         /* Check if the time is valid */
83         if (readl(rtap->virtbase + COH901331_VALID)) {
84                 rtc_time_to_tm(readl(rtap->virtbase + COH901331_CUR_TIME), tm);
85                 clk_disable(rtap->clk);
86                 return rtc_valid_tm(tm);
87         }
88         clk_disable(rtap->clk);
89         return -EINVAL;
90 }
91
92 static int coh901331_set_mmss(struct device *dev, unsigned long secs)
93 {
94         struct coh901331_port *rtap = dev_get_drvdata(dev);
95
96         clk_enable(rtap->clk);
97         writel(secs, rtap->virtbase + COH901331_SET_TIME);
98         clk_disable(rtap->clk);
99
100         return 0;
101 }
102
103 static int coh901331_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
104 {
105         struct coh901331_port *rtap = dev_get_drvdata(dev);
106
107         clk_enable(rtap->clk);
108         rtc_time_to_tm(readl(rtap->virtbase + COH901331_ALARM), &alarm->time);
109         alarm->pending = readl(rtap->virtbase + COH901331_IRQ_EVENT) & 1U;
110         alarm->enabled = readl(rtap->virtbase + COH901331_IRQ_MASK) & 1U;
111         clk_disable(rtap->clk);
112
113         return 0;
114 }
115
116 static int coh901331_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
117 {
118         struct coh901331_port *rtap = dev_get_drvdata(dev);
119         unsigned long time;
120
121         rtc_tm_to_time(&alarm->time, &time);
122         clk_enable(rtap->clk);
123         writel(time, rtap->virtbase + COH901331_ALARM);
124         writel(alarm->enabled, rtap->virtbase + COH901331_IRQ_MASK);
125         clk_disable(rtap->clk);
126
127         return 0;
128 }
129
130 static int coh901331_alarm_irq_enable(struct device *dev, unsigned int enabled)
131 {
132         struct coh901331_port *rtap = dev_get_drvdata(dev);
133
134         clk_enable(rtap->clk);
135         if (enabled)
136                 writel(1, rtap->virtbase + COH901331_IRQ_MASK);
137         else
138                 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
139         clk_disable(rtap->clk);
140
141         return 0;
142 }
143
144 static struct rtc_class_ops coh901331_ops = {
145         .read_time = coh901331_read_time,
146         .set_mmss = coh901331_set_mmss,
147         .read_alarm = coh901331_read_alarm,
148         .set_alarm = coh901331_set_alarm,
149         .alarm_irq_enable = coh901331_alarm_irq_enable,
150 };
151
152 static int __exit coh901331_remove(struct platform_device *pdev)
153 {
154         struct coh901331_port *rtap = dev_get_drvdata(&pdev->dev);
155
156         if (rtap) {
157                 free_irq(rtap->irq, rtap);
158                 rtc_device_unregister(rtap->rtc);
159                 clk_put(rtap->clk);
160                 iounmap(rtap->virtbase);
161                 release_mem_region(rtap->phybase, rtap->physize);
162                 platform_set_drvdata(pdev, NULL);
163                 kfree(rtap);
164         }
165
166         return 0;
167 }
168
169
170 static int __init coh901331_probe(struct platform_device *pdev)
171 {
172         int ret;
173         struct coh901331_port *rtap;
174         struct resource *res;
175
176         rtap = kzalloc(sizeof(struct coh901331_port), GFP_KERNEL);
177         if (!rtap)
178                 return -ENOMEM;
179
180         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
181         if (!res) {
182                 ret = -ENOENT;
183                 goto out_no_resource;
184         }
185         rtap->phybase = res->start;
186         rtap->physize = resource_size(res);
187
188         if (request_mem_region(rtap->phybase, rtap->physize,
189                                "rtc-coh901331") == NULL) {
190                 ret = -EBUSY;
191                 goto out_no_memregion;
192         }
193
194         rtap->virtbase = ioremap(rtap->phybase, rtap->physize);
195         if (!rtap->virtbase) {
196                 ret = -ENOMEM;
197                 goto out_no_remap;
198         }
199
200         rtap->irq = platform_get_irq(pdev, 0);
201         if (request_irq(rtap->irq, coh901331_interrupt, IRQF_DISABLED,
202                         "RTC COH 901 331 Alarm", rtap)) {
203                 ret = -EIO;
204                 goto out_no_irq;
205         }
206
207         rtap->clk = clk_get(&pdev->dev, NULL);
208         if (IS_ERR(rtap->clk)) {
209                 ret = PTR_ERR(rtap->clk);
210                 dev_err(&pdev->dev, "could not get clock\n");
211                 goto out_no_clk;
212         }
213
214         /* We enable/disable the clock only to assure it works */
215         ret = clk_enable(rtap->clk);
216         if (ret) {
217                 dev_err(&pdev->dev, "could not enable clock\n");
218                 goto out_no_clk_enable;
219         }
220         clk_disable(rtap->clk);
221
222         rtap->rtc = rtc_device_register("coh901331", &pdev->dev, &coh901331_ops,
223                                          THIS_MODULE);
224         if (IS_ERR(rtap->rtc)) {
225                 ret = PTR_ERR(rtap->rtc);
226                 goto out_no_rtc;
227         }
228
229         platform_set_drvdata(pdev, rtap);
230
231         return 0;
232
233  out_no_rtc:
234  out_no_clk_enable:
235         clk_put(rtap->clk);
236  out_no_clk:
237         free_irq(rtap->irq, rtap);
238  out_no_irq:
239         iounmap(rtap->virtbase);
240  out_no_remap:
241         platform_set_drvdata(pdev, NULL);
242  out_no_memregion:
243         release_mem_region(rtap->phybase, SZ_4K);
244  out_no_resource:
245         kfree(rtap);
246         return ret;
247 }
248
249 #ifdef CONFIG_PM
250 static int coh901331_suspend(struct platform_device *pdev, pm_message_t state)
251 {
252         struct coh901331_port *rtap = dev_get_drvdata(&pdev->dev);
253
254         /*
255          * If this RTC alarm will be used for waking the system up,
256          * don't disable it of course. Else we just disable the alarm
257          * and await suspension.
258          */
259         if (device_may_wakeup(&pdev->dev)) {
260                 enable_irq_wake(rtap->irq);
261         } else {
262                 clk_enable(rtap->clk);
263                 rtap->irqmaskstore = readl(rtap->virtbase + COH901331_IRQ_MASK);
264                 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
265                 clk_disable(rtap->clk);
266         }
267         return 0;
268 }
269
270 static int coh901331_resume(struct platform_device *pdev)
271 {
272         struct coh901331_port *rtap = dev_get_drvdata(&pdev->dev);
273
274         if (device_may_wakeup(&pdev->dev))
275                 disable_irq_wake(rtap->irq);
276         else
277                 clk_enable(rtap->clk);
278                 writel(rtap->irqmaskstore, rtap->virtbase + COH901331_IRQ_MASK);
279                 clk_disable(rtap->clk);
280         return 0;
281 }
282 #else
283 #define coh901331_suspend NULL
284 #define coh901331_resume NULL
285 #endif
286
287 static void coh901331_shutdown(struct platform_device *pdev)
288 {
289         struct coh901331_port *rtap = dev_get_drvdata(&pdev->dev);
290
291         clk_enable(rtap->clk);
292         writel(0, rtap->virtbase + COH901331_IRQ_MASK);
293         clk_disable(rtap->clk);
294 }
295
296 static struct platform_driver coh901331_driver = {
297         .driver = {
298                 .name = "rtc-coh901331",
299                 .owner = THIS_MODULE,
300         },
301         .remove = __exit_p(coh901331_remove),
302         .suspend = coh901331_suspend,
303         .resume = coh901331_resume,
304         .shutdown = coh901331_shutdown,
305 };
306
307 static int __init coh901331_init(void)
308 {
309         return platform_driver_probe(&coh901331_driver, coh901331_probe);
310 }
311
312 static void __exit coh901331_exit(void)
313 {
314         platform_driver_unregister(&coh901331_driver);
315 }
316
317 module_init(coh901331_init);
318 module_exit(coh901331_exit);
319
320 MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
321 MODULE_DESCRIPTION("ST-Ericsson AB COH 901 331 RTC Driver");
322 MODULE_LICENSE("GPL");