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aa958f57 LW |
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); | |
378ce74b LW |
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); | |
aa958f57 | 69 | clk_disable(rtap->clk); |
378ce74b | 70 | |
aa958f57 LW |
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); | |
378ce74b LW |
140 | |
141 | return 0; | |
aa958f57 LW |
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"); |