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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         int                     irq_alarm;
 83         struct rtc_device       *rtc;
 84         spinlock_t              lock;           /* Protects this structure */
 85 };
 86 
 87 static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
 88 {
 89         struct vt8500_rtc *vt8500_rtc = dev_id;
 90         u32 isr;
 91         unsigned long events = 0;
 92 
 93         spin_lock(&vt8500_rtc->lock);
 94 
 95         /* clear interrupt sources */
 96         isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
 97         writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
 98 
 99         spin_unlock(&vt8500_rtc->lock);
100 
101         if (isr & VT8500_RTC_IS_ALARM)
102                 events |= RTC_AF | RTC_IRQF;
103 
104         rtc_update_irq(vt8500_rtc->rtc, 1, events);
105 
106         return IRQ_HANDLED;
107 }
108 
109 static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
110 {
111         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
112         u32 date, time;
113 
114         date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
115         time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
116 
117         tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
118         tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
119         tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
120         tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
121         tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S) - 1;
122         tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S)
123                         + ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
124         tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
125 
126         return 0;
127 }
128 
129 static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
130 {
131         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
132 
133         if (tm->tm_year < 100) {
134                 dev_warn(dev, "Only years 2000-2199 are supported by the "
135                               "hardware!\n");
136                 return -EINVAL;
137         }
138 
139         writel((bin2bcd(tm->tm_year % 100) << DATE_YEAR_S)
140                 | (bin2bcd(tm->tm_mon + 1) << DATE_MONTH_S)
141                 | (bin2bcd(tm->tm_mday))
142                 | ((tm->tm_year >= 200) << DATE_CENTURY_S),
143                 vt8500_rtc->regbase + VT8500_RTC_DS);
144         writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
145                 | (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
146                 | (bin2bcd(tm->tm_min) << TIME_MIN_S)
147                 | (bin2bcd(tm->tm_sec)),
148                 vt8500_rtc->regbase + VT8500_RTC_TS);
149 
150         return 0;
151 }
152 
153 static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
154 {
155         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
156         u32 isr, alarm;
157 
158         alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
159         isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
160 
161         alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
162         alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
163         alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
164         alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
165 
166         alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
167         alrm->pending = (isr & VT8500_RTC_IS_ALARM) ? 1 : 0;
168 
169         return rtc_valid_tm(&alrm->time);
170 }
171 
172 static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
173 {
174         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
175 
176         writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
177                 | (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
178                 | (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
179                 | (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
180                 | (bin2bcd(alrm->time.tm_sec)),
181                 vt8500_rtc->regbase + VT8500_RTC_AS);
182 
183         return 0;
184 }
185 
186 static int vt8500_alarm_irq_enable(struct device *dev, unsigned int enabled)
187 {
188         struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
189         unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
190 
191         if (enabled)
192                 tmp |= ALARM_ENABLE_MASK;
193         else
194                 tmp &= ~ALARM_ENABLE_MASK;
195 
196         writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
197         return 0;
198 }
199 
200 static const struct rtc_class_ops vt8500_rtc_ops = {
201         .read_time = vt8500_rtc_read_time,
202         .set_time = vt8500_rtc_set_time,
203         .read_alarm = vt8500_rtc_read_alarm,
204         .set_alarm = vt8500_rtc_set_alarm,
205         .alarm_irq_enable = vt8500_alarm_irq_enable,
206 };
207 
208 static int vt8500_rtc_probe(struct platform_device *pdev)
209 {
210         struct vt8500_rtc *vt8500_rtc;
211         struct resource *res;
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->irq_alarm = platform_get_irq(pdev, 0);
223         if (vt8500_rtc->irq_alarm < 0) {
224                 dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
225                 return vt8500_rtc->irq_alarm;
226         }
227 
228         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
229         vt8500_rtc->regbase = devm_ioremap_resource(&pdev->dev, res);
230         if (IS_ERR(vt8500_rtc->regbase))
231                 return PTR_ERR(vt8500_rtc->regbase);
232 
233         /* Enable RTC and set it to 24-hour mode */
234         writel(VT8500_RTC_CR_ENABLE,
235                vt8500_rtc->regbase + VT8500_RTC_CR);
236 
237         vt8500_rtc->rtc = devm_rtc_device_register(&pdev->dev, "vt8500-rtc",
238                                               &vt8500_rtc_ops, THIS_MODULE);
239         if (IS_ERR(vt8500_rtc->rtc)) {
240                 ret = PTR_ERR(vt8500_rtc->rtc);
241                 dev_err(&pdev->dev,
242                         "Failed to register RTC device -> %d\n", ret);
243                 goto err_return;
244         }
245 
246         ret = devm_request_irq(&pdev->dev, vt8500_rtc->irq_alarm,
247                                 vt8500_rtc_irq, 0, "rtc alarm", vt8500_rtc);
248         if (ret < 0) {
249                 dev_err(&pdev->dev, "can't get irq %i, err %d\n",
250                         vt8500_rtc->irq_alarm, ret);
251                 goto err_return;
252         }
253 
254         return 0;
255 
256 err_return:
257         return ret;
258 }
259 
260 static int vt8500_rtc_remove(struct platform_device *pdev)
261 {
262         struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
263 
264         /* Disable alarm matching */
265         writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
266 
267         return 0;
268 }
269 
270 static const struct of_device_id wmt_dt_ids[] = {
271         { .compatible = "via,vt8500-rtc", },
272         {}
273 };
274 
275 static struct platform_driver vt8500_rtc_driver = {
276         .probe          = vt8500_rtc_probe,
277         .remove         = vt8500_rtc_remove,
278         .driver         = {
279                 .name   = "vt8500-rtc",
280                 .owner  = THIS_MODULE,
281                 .of_match_table = wmt_dt_ids,
282         },
283 };
284 
285 module_platform_driver(vt8500_rtc_driver);
286 
287 MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
288 MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
289 MODULE_LICENSE("GPL v2");
290 MODULE_ALIAS("platform:vt8500-rtc");
291 

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