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