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_SLEEP
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 clk_unprepare(rtap->clk);
159 platform_set_drvdata(pdev, NULL);
160 }
161
162 return 0;
163 }
164
165
coh901331_probe(struct platform_device * pdev)166 static int __init coh901331_probe(struct platform_device *pdev)
167 {
168 int ret;
169 struct coh901331_port *rtap;
170 struct resource *res;
171
172 rtap = devm_kzalloc(&pdev->dev,
173 sizeof(struct coh901331_port), GFP_KERNEL);
174 if (!rtap)
175 return -ENOMEM;
176
177 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
178 if (!res)
179 return -ENOENT;
180
181 rtap->phybase = res->start;
182 rtap->physize = resource_size(res);
183
184 if (devm_request_mem_region(&pdev->dev, rtap->phybase, rtap->physize,
185 "rtc-coh901331") == NULL)
186 return -EBUSY;
187
188 rtap->virtbase = devm_ioremap(&pdev->dev, rtap->phybase, rtap->physize);
189 if (!rtap->virtbase)
190 return -ENOMEM;
191
192 rtap->irq = platform_get_irq(pdev, 0);
193 if (devm_request_irq(&pdev->dev, rtap->irq, coh901331_interrupt, 0,
194 "RTC COH 901 331 Alarm", rtap))
195 return -EIO;
196
197 rtap->clk = devm_clk_get(&pdev->dev, NULL);
198 if (IS_ERR(rtap->clk)) {
199 ret = PTR_ERR(rtap->clk);
200 dev_err(&pdev->dev, "could not get clock\n");
201 return ret;
202 }
203
204 /* We enable/disable the clock only to assure it works */
205 ret = clk_prepare_enable(rtap->clk);
206 if (ret) {
207 dev_err(&pdev->dev, "could not enable clock\n");
208 return ret;
209 }
210 clk_disable(rtap->clk);
211
212 platform_set_drvdata(pdev, rtap);
213 rtap->rtc = devm_rtc_device_register(&pdev->dev, "coh901331",
214 &coh901331_ops, THIS_MODULE);
215 if (IS_ERR(rtap->rtc)) {
216 ret = PTR_ERR(rtap->rtc);
217 goto out_no_rtc;
218 }
219
220 return 0;
221
222 out_no_rtc:
223 platform_set_drvdata(pdev, NULL);
224 clk_unprepare(rtap->clk);
225 return ret;
226 }
227
228 #ifdef CONFIG_PM_SLEEP
coh901331_suspend(struct device * dev)229 static int coh901331_suspend(struct device *dev)
230 {
231 struct coh901331_port *rtap = dev_get_drvdata(dev);
232
233 /*
234 * If this RTC alarm will be used for waking the system up,
235 * don't disable it of course. Else we just disable the alarm
236 * and await suspension.
237 */
238 if (device_may_wakeup(dev)) {
239 enable_irq_wake(rtap->irq);
240 } else {
241 clk_enable(rtap->clk);
242 rtap->irqmaskstore = readl(rtap->virtbase + COH901331_IRQ_MASK);
243 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
244 clk_disable(rtap->clk);
245 }
246 clk_unprepare(rtap->clk);
247 return 0;
248 }
249
coh901331_resume(struct device * dev)250 static int coh901331_resume(struct device *dev)
251 {
252 struct coh901331_port *rtap = dev_get_drvdata(dev);
253
254 clk_prepare(rtap->clk);
255 if (device_may_wakeup(dev)) {
256 disable_irq_wake(rtap->irq);
257 } else {
258 clk_enable(rtap->clk);
259 writel(rtap->irqmaskstore, rtap->virtbase + COH901331_IRQ_MASK);
260 clk_disable(rtap->clk);
261 }
262 return 0;
263 }
264 #endif
265
266 static SIMPLE_DEV_PM_OPS(coh901331_pm_ops, coh901331_suspend, coh901331_resume);
267
coh901331_shutdown(struct platform_device * pdev)268 static void coh901331_shutdown(struct platform_device *pdev)
269 {
270 struct coh901331_port *rtap = dev_get_drvdata(&pdev->dev);
271
272 clk_enable(rtap->clk);
273 writel(0, rtap->virtbase + COH901331_IRQ_MASK);
274 clk_disable_unprepare(rtap->clk);
275 }
276
277 static struct platform_driver coh901331_driver = {
278 .driver = {
279 .name = "rtc-coh901331",
280 .owner = THIS_MODULE,
281 .pm = &coh901331_pm_ops,
282 },
283 .remove = __exit_p(coh901331_remove),
284 .shutdown = coh901331_shutdown,
285 };
286
287 module_platform_driver_probe(coh901331_driver, coh901331_probe);
288
289 MODULE_AUTHOR("Linus Walleij <linus.walleij@stericsson.com>");
290 MODULE_DESCRIPTION("ST-Ericsson AB COH 901 331 RTC Driver");
291 MODULE_LICENSE("GPL");
292