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
coh901331_interrupt(int irq,void * data)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
coh901331_read_time(struct device * dev,struct rtc_time * tm)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
coh901331_set_mmss(struct device * dev,unsigned long secs)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
coh901331_read_alarm(struct device * dev,struct rtc_wkalrm * alarm)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
coh901331_set_alarm(struct device * dev,struct rtc_wkalrm * alarm)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
coh901331_alarm_irq_enable(struct device * dev,unsigned int enabled)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
coh901331_remove(struct platform_device * pdev)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
coh901331_probe(struct platform_device * pdev)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
coh901331_suspend(struct platform_device * pdev,pm_message_t state)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
coh901331_resume(struct platform_device * pdev)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
coh901331_shutdown(struct platform_device * pdev)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
coh901331_init(void)309 static int __init coh901331_init(void)
310 {
311 return platform_driver_probe(&coh901331_driver, coh901331_probe);
312 }
313
coh901331_exit(void)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");
325