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Linux/drivers/rtc/rtc-vt8500.c

  1 /*
  2  * drivers/rtc/rtc-vt8500.c
  3  *
  4  *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
  5  *
  6  * Based on rtc-pxa.c
  7  *
  8  * This software is licensed under the terms of the GNU General Public
  9  * License version 2, as published by the Free Software Foundation, and
 10  * may be copied, distributed, and modified under those terms.
 11  *
 12  * This program is distributed in the hope that it will be useful,
 13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 15  * GNU General Public License for more details.
 16  */
 17 
 18 #include <linux/module.h>
 19 #include <linux/rtc.h>
 20 #include <linux/init.h>
 21 #include <linux/interrupt.h>
 22 #include <linux/io.h>
 23 #include <linux/bcd.h>
 24 #include <linux/platform_device.h>
 25 #include <linux/slab.h>
 26 #include <linux/of.h>
 27 
 28 /*
 29  * Register definitions
 30  */
 31 #define VT8500_RTC_TS           0x00    /* Time set */
 32 #define VT8500_RTC_DS           0x04    /* Date set */
 33 #define VT8500_RTC_AS           0x08    /* Alarm set */
 34 #define VT8500_RTC_CR           0x0c    /* Control */
 35 #define VT8500_RTC_TR           0x10    /* Time read */
 36 #define VT8500_RTC_DR           0x14    /* Date read */
 37 #define VT8500_RTC_WS           0x18    /* Write status */
 38 #define VT8500_RTC_CL           0x20    /* Calibration */
 39 #define VT8500_RTC_IS           0x24    /* Interrupt status */
 40 #define VT8500_RTC_ST           0x28    /* Status */
 41 
 42 #define INVALID_TIME_BIT        (1 << 31)
 43 
 44 #define DATE_CENTURY_S          19
 45 #define DATE_YEAR_S             11
 46 #define DATE_YEAR_MASK          (0xff << DATE_YEAR_S)
 47 #define DATE_MONTH_S            6
 48 #define DATE_MONTH_MASK         (0x1f << DATE_MONTH_S)
 49 #define DATE_DAY_MASK           0x3f
 50 
 51 #define TIME_DOW_S              20
 52 #define TIME_DOW_MASK           (0x07 << TIME_DOW_S)
 53 #define TIME_HOUR_S             14
 54 #define TIME_HOUR_MASK          (0x3f << TIME_HOUR_S)
 55 #define TIME_MIN_S              7
 56 #define TIME_MIN_MASK           (0x7f << TIME_MIN_S)
 57 #define TIME_SEC_MASK           0x7f
 58 
 59 #define ALARM_DAY_S             20
 60 #define ALARM_DAY_MASK          (0x3f << ALARM_DAY_S)
 61 
 62 #define ALARM_DAY_BIT           (1 << 29)
 63 #define ALARM_HOUR_BIT          (1 << 28)
 64 #define ALARM_MIN_BIT           (1 << 27)
 65 #define ALARM_SEC_BIT           (1 << 26)
 66 
 67 #define ALARM_ENABLE_MASK       (ALARM_DAY_BIT \
 68                                 | ALARM_HOUR_BIT \
 69                                 | ALARM_MIN_BIT \
 70                                 | ALARM_SEC_BIT)
 71 
 72 #define VT8500_RTC_CR_ENABLE    (1 << 0)        /* Enable RTC */
 73 #define VT8500_RTC_CR_12H       (1 << 1)        /* 12h time format */
 74 #define VT8500_RTC_CR_SM_ENABLE (1 << 2)        /* Enable periodic irqs */
 75 #define VT8500_RTC_CR_SM_SEC    (1 << 3)        /* 0: 1Hz/60, 1: 1Hz */
 76 #define VT8500_RTC_CR_CALIB     (1 << 4)        /* Enable calibration */
 77 
 78 #define VT8500_RTC_IS_ALARM     (1 << 0)        /* Alarm interrupt status */
 79 
 80 struct vt8500_rtc {
 81         void __iomem            *regbase;
 82         struct resource         *res;
 83         int                     irq_alarm;
 84         struct rtc_device       *rtc;
 85         spinlock_t              lock;           /* Protects this structure */
 86 };
 87 
 88 static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
 89 {
 90         struct vt8500_rtc *vt8500_rtc = dev_id;
 91         u32 isr;
 92         unsigned long events = 0;
 93 
 94         spin_lock(&vt8500_rtc->lock);
 95 
 96         /* clear interrupt sources */
 97         isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
 98         writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
 99 
100         spin_unlock(&vt8500_rtc->lock);
101 
102         if (isr & VT8500_RTC_IS_ALARM)
103                 events |= RTC_AF | RTC_IRQF;
104 
105         rtc_update_irq(vt8500_rtc->rtc, 1, events);
106 
107         return IRQ_HANDLED;
108 }
109 
110 static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
111 {
112         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
113         u32 date, time;
114 
115         date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
116         time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
117 
118         tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
119         tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
120         tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
121         tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
122         tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S) - 1;
123         tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
124                         + ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
125         tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
126 
127         return 0;
128 }
129 
130 static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
131 {
132         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
133 
134         if (tm->tm_year < 100) {
135                 dev_warn(dev, "Only years 2000-2199 are supported by the "
136                               "hardware!\n");
137                 return -EINVAL;
138         }
139 
140         writel((bin2bcd(tm->tm_year % 100) << DATE_YEAR_S)
141                 | (bin2bcd(tm->tm_mon + 1) << DATE_MONTH_S)
142                 | (bin2bcd(tm->tm_mday))
143                 | ((tm->tm_year >= 200) << DATE_CENTURY_S),
144                 vt8500_rtc->regbase + VT8500_RTC_DS);
145         writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
146                 | (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
147                 | (bin2bcd(tm->tm_min) << TIME_MIN_S)
148                 | (bin2bcd(tm->tm_sec)),
149                 vt8500_rtc->regbase + VT8500_RTC_TS);
150 
151         return 0;
152 }
153 
154 static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
155 {
156         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
157         u32 isr, alarm;
158 
159         alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
160         isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
161 
162         alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
163         alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
164         alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
165         alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
166 
167         alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
168         alrm->pending = (isr & VT8500_RTC_IS_ALARM) ? 1 : 0;
169 
170         return rtc_valid_tm(&alrm->time);
171 }
172 
173 static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
174 {
175         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
176 
177         writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
178                 | (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
179                 | (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
180                 | (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
181                 | (bin2bcd(alrm->time.tm_sec)),
182                 vt8500_rtc->regbase + VT8500_RTC_AS);
183 
184         return 0;
185 }
186 
187 static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
188 {
189         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
190         unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
191 
192         if (enabled)
193                 tmp |= ALARM_ENABLE_MASK;
194         else
195                 tmp &= ~ALARM_ENABLE_MASK;
196 
197         writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
198         return 0;
199 }
200 
201 static const struct rtc_class_ops vt8500_rtc_ops = {
202         .read_time = vt8500_rtc_read_time,
203         .set_time = vt8500_rtc_set_time,
204         .read_alarm = vt8500_rtc_read_alarm,
205         .set_alarm = vt8500_rtc_set_alarm,
206         .alarm_irq_enable = vt8500_alarm_irq_enable,
207 };
208 
209 static int vt8500_rtc_probe(struct platform_device *pdev)
210 {
211         struct vt8500_rtc *vt8500_rtc;
212         int ret;
213 
214         vt8500_rtc = devm_kzalloc(&pdev->dev,
215                            sizeof(struct vt8500_rtc), GFP_KERNEL);
216         if (!vt8500_rtc)
217                 return -ENOMEM;
218 
219         spin_lock_init(&vt8500_rtc->lock);
220         platform_set_drvdata(pdev, vt8500_rtc);
221 
222         vt8500_rtc->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
223         if (!vt8500_rtc->res) {
224                 dev_err(&pdev->dev, "No I/O memory resource defined\n");
225                 return -ENXIO;
226         }
227 
228         vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
229         if (vt8500_rtc->irq_alarm < 0) {
230                 dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
231                 return vt8500_rtc->irq_alarm;
232         }
233 
234         vt8500_rtc->res = devm_request_mem_region(&pdev->dev,
235                                         vt8500_rtc->res->start,
236                                         resource_size(vt8500_rtc->res),
237                                         "vt8500-rtc");
238         if (vt8500_rtc->res == NULL) {
239                 dev_err(&pdev->dev, "failed to request I/O memory\n");
240                 return -EBUSY;
241         }
242 
243         vt8500_rtc->regbase = devm_ioremap(&pdev->dev, vt8500_rtc->res->start,
244                                       resource_size(vt8500_rtc->res));
245         if (!vt8500_rtc->regbase) {
246                 dev_err(&pdev->dev, "Unable to map RTC I/O memory\n");
247                 ret = -EBUSY;
248                 goto err_return;
249         }
250 
251         /* Enable RTC and set it to 24-hour mode */
252         writel(VT8500_RTC_CR_ENABLE,
253                vt8500_rtc->regbase + VT8500_RTC_CR);
254 
255         vt8500_rtc->rtc = devm_rtc_device_register(&pdev->dev, "vt8500-rtc",
256                                               &vt8500_rtc_ops, THIS_MODULE);
257         if (IS_ERR(vt8500_rtc->rtc)) {
258                 ret = PTR_ERR(vt8500_rtc->rtc);
259                 dev_err(&pdev->dev,
260                         "Failed to register RTC device -> %d\n", ret);
261                 goto err_return;
262         }
263 
264         ret = devm_request_irq(&pdev->dev, vt8500_rtc->irq_alarm,
265                                 vt8500_rtc_irq, 0, "rtc alarm", vt8500_rtc);
266         if (ret < 0) {
267                 dev_err(&pdev->dev, "can't get irq %i, err %d\n",
268                         vt8500_rtc->irq_alarm, ret);
269                 goto err_return;
270         }
271 
272         return 0;
273 
274 err_return:
275         return ret;
276 }
277 
278 static int vt8500_rtc_remove(struct platform_device *pdev)
279 {
280         struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
281 
282         /* Disable alarm matching */
283         writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
284 
285         return 0;
286 }
287 
288 static const struct of_device_id wmt_dt_ids[] = {
289         { .compatible = "via,vt8500-rtc", },
290         {}
291 };
292 
293 static struct platform_driver vt8500_rtc_driver = {
294         .probe          = vt8500_rtc_probe,
295         .remove         = vt8500_rtc_remove,
296         .driver         = {
297                 .name   = "vt8500-rtc",
298                 .owner  = THIS_MODULE,
299                 .of_match_table = wmt_dt_ids,
300         },
301 };
302 
303 module_platform_driver(vt8500_rtc_driver);
304 
305 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
306 MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
307 MODULE_LICENSE("GPL v2");
308 MODULE_ALIAS("platform:vt8500-rtc");
309 

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