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Linux/drivers/rtc/rtc-stk17ta8.c

  1 /*
  2  * A RTC driver for the Simtek STK17TA8
  3  *
  4  * By Thomas Hommel <thomas.hommel@ge.com>
  5  *
  6  * Based on the DS1553 driver from
  7  * Atsushi Nemoto <anemo@mba.ocn.ne.jp>
  8  *
  9  * This program is free software; you can redistribute it and/or modify
 10  * it under the terms of the GNU General Public License version 2 as
 11  * published by the Free Software Foundation.
 12  */
 13 
 14 #include <linux/bcd.h>
 15 #include <linux/init.h>
 16 #include <linux/kernel.h>
 17 #include <linux/gfp.h>
 18 #include <linux/delay.h>
 19 #include <linux/jiffies.h>
 20 #include <linux/interrupt.h>
 21 #include <linux/rtc.h>
 22 #include <linux/platform_device.h>
 23 #include <linux/io.h>
 24 #include <linux/module.h>
 25 
 26 #define DRV_VERSION "0.1"
 27 
 28 #define RTC_REG_SIZE            0x20000
 29 #define RTC_OFFSET              0x1fff0
 30 
 31 #define RTC_FLAGS               (RTC_OFFSET + 0)
 32 #define RTC_CENTURY             (RTC_OFFSET + 1)
 33 #define RTC_SECONDS_ALARM       (RTC_OFFSET + 2)
 34 #define RTC_MINUTES_ALARM       (RTC_OFFSET + 3)
 35 #define RTC_HOURS_ALARM         (RTC_OFFSET + 4)
 36 #define RTC_DATE_ALARM          (RTC_OFFSET + 5)
 37 #define RTC_INTERRUPTS          (RTC_OFFSET + 6)
 38 #define RTC_WATCHDOG            (RTC_OFFSET + 7)
 39 #define RTC_CALIBRATION         (RTC_OFFSET + 8)
 40 #define RTC_SECONDS             (RTC_OFFSET + 9)
 41 #define RTC_MINUTES             (RTC_OFFSET + 10)
 42 #define RTC_HOURS               (RTC_OFFSET + 11)
 43 #define RTC_DAY                 (RTC_OFFSET + 12)
 44 #define RTC_DATE                (RTC_OFFSET + 13)
 45 #define RTC_MONTH               (RTC_OFFSET + 14)
 46 #define RTC_YEAR                (RTC_OFFSET + 15)
 47 
 48 #define RTC_SECONDS_MASK        0x7f
 49 #define RTC_DAY_MASK            0x07
 50 #define RTC_CAL_MASK            0x3f
 51 
 52 /* Bits in the Calibration register */
 53 #define RTC_STOP                0x80
 54 
 55 /* Bits in the Flags register */
 56 #define RTC_FLAGS_AF            0x40
 57 #define RTC_FLAGS_PF            0x20
 58 #define RTC_WRITE               0x02
 59 #define RTC_READ                0x01
 60 
 61 /* Bits in the Interrupts register */
 62 #define RTC_INTS_AIE            0x40
 63 
 64 struct rtc_plat_data {
 65         struct rtc_device *rtc;
 66         void __iomem *ioaddr;
 67         unsigned long last_jiffies;
 68         int irq;
 69         unsigned int irqen;
 70         int alrm_sec;
 71         int alrm_min;
 72         int alrm_hour;
 73         int alrm_mday;
 74         spinlock_t lock;
 75 };
 76 
 77 static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time *tm)
 78 {
 79         struct platform_device *pdev = to_platform_device(dev);
 80         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
 81         void __iomem *ioaddr = pdata->ioaddr;
 82         u8 flags;
 83 
 84         flags = readb(pdata->ioaddr + RTC_FLAGS);
 85         writeb(flags | RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
 86 
 87         writeb(bin2bcd(tm->tm_year % 100), ioaddr + RTC_YEAR);
 88         writeb(bin2bcd(tm->tm_mon + 1), ioaddr + RTC_MONTH);
 89         writeb(bin2bcd(tm->tm_wday) & RTC_DAY_MASK, ioaddr + RTC_DAY);
 90         writeb(bin2bcd(tm->tm_mday), ioaddr + RTC_DATE);
 91         writeb(bin2bcd(tm->tm_hour), ioaddr + RTC_HOURS);
 92         writeb(bin2bcd(tm->tm_min), ioaddr + RTC_MINUTES);
 93         writeb(bin2bcd(tm->tm_sec) & RTC_SECONDS_MASK, ioaddr + RTC_SECONDS);
 94         writeb(bin2bcd((tm->tm_year + 1900) / 100), ioaddr + RTC_CENTURY);
 95 
 96         writeb(flags & ~RTC_WRITE, pdata->ioaddr + RTC_FLAGS);
 97         return 0;
 98 }
 99 
100 static int stk17ta8_rtc_read_time(struct device *dev, struct rtc_time *tm)
101 {
102         struct platform_device *pdev = to_platform_device(dev);
103         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
104         void __iomem *ioaddr = pdata->ioaddr;
105         unsigned int year, month, day, hour, minute, second, week;
106         unsigned int century;
107         u8 flags;
108 
109         /* give enough time to update RTC in case of continuous read */
110         if (pdata->last_jiffies == jiffies)
111                 msleep(1);
112         pdata->last_jiffies = jiffies;
113 
114         flags = readb(pdata->ioaddr + RTC_FLAGS);
115         writeb(flags | RTC_READ, ioaddr + RTC_FLAGS);
116         second = readb(ioaddr + RTC_SECONDS) & RTC_SECONDS_MASK;
117         minute = readb(ioaddr + RTC_MINUTES);
118         hour = readb(ioaddr + RTC_HOURS);
119         day = readb(ioaddr + RTC_DATE);
120         week = readb(ioaddr + RTC_DAY) & RTC_DAY_MASK;
121         month = readb(ioaddr + RTC_MONTH);
122         year = readb(ioaddr + RTC_YEAR);
123         century = readb(ioaddr + RTC_CENTURY);
124         writeb(flags & ~RTC_READ, ioaddr + RTC_FLAGS);
125         tm->tm_sec = bcd2bin(second);
126         tm->tm_min = bcd2bin(minute);
127         tm->tm_hour = bcd2bin(hour);
128         tm->tm_mday = bcd2bin(day);
129         tm->tm_wday = bcd2bin(week);
130         tm->tm_mon = bcd2bin(month) - 1;
131         /* year is 1900 + tm->tm_year */
132         tm->tm_year = bcd2bin(year) + bcd2bin(century) * 100 - 1900;
133 
134         if (rtc_valid_tm(tm) < 0) {
135                 dev_err(dev, "retrieved date/time is not valid.\n");
136                 rtc_time_to_tm(0, tm);
137         }
138         return 0;
139 }
140 
141 static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *pdata)
142 {
143         void __iomem *ioaddr = pdata->ioaddr;
144         unsigned long irqflags;
145         u8 flags;
146 
147         spin_lock_irqsave(&pdata->lock, irqflags);
148 
149         flags = readb(ioaddr + RTC_FLAGS);
150         writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
151 
152         writeb(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
153                0x80 : bin2bcd(pdata->alrm_mday),
154                ioaddr + RTC_DATE_ALARM);
155         writeb(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
156                0x80 : bin2bcd(pdata->alrm_hour),
157                ioaddr + RTC_HOURS_ALARM);
158         writeb(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
159                0x80 : bin2bcd(pdata->alrm_min),
160                ioaddr + RTC_MINUTES_ALARM);
161         writeb(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
162                0x80 : bin2bcd(pdata->alrm_sec),
163                ioaddr + RTC_SECONDS_ALARM);
164         writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS);
165         readb(ioaddr + RTC_FLAGS);      /* clear interrupts */
166         writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
167         spin_unlock_irqrestore(&pdata->lock, irqflags);
168 }
169 
170 static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
171 {
172         struct platform_device *pdev = to_platform_device(dev);
173         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
174 
175         if (pdata->irq <= 0)
176                 return -EINVAL;
177         pdata->alrm_mday = alrm->time.tm_mday;
178         pdata->alrm_hour = alrm->time.tm_hour;
179         pdata->alrm_min = alrm->time.tm_min;
180         pdata->alrm_sec = alrm->time.tm_sec;
181         if (alrm->enabled)
182                 pdata->irqen |= RTC_AF;
183         stk17ta8_rtc_update_alarm(pdata);
184         return 0;
185 }
186 
187 static int stk17ta8_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
188 {
189         struct platform_device *pdev = to_platform_device(dev);
190         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
191 
192         if (pdata->irq <= 0)
193                 return -EINVAL;
194         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
195         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
196         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
197         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
198         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
199         return 0;
200 }
201 
202 static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id)
203 {
204         struct platform_device *pdev = dev_id;
205         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
206         void __iomem *ioaddr = pdata->ioaddr;
207         unsigned long events = 0;
208 
209         spin_lock(&pdata->lock);
210         /* read and clear interrupt */
211         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
212                 events = RTC_IRQF;
213                 if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
214                         events |= RTC_UF;
215                 else
216                         events |= RTC_AF;
217                 rtc_update_irq(pdata->rtc, 1, events);
218         }
219         spin_unlock(&pdata->lock);
220         return events ? IRQ_HANDLED : IRQ_NONE;
221 }
222 
223 static int stk17ta8_rtc_alarm_irq_enable(struct device *dev,
224         unsigned int enabled)
225 {
226         struct platform_device *pdev = to_platform_device(dev);
227         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
228 
229         if (pdata->irq <= 0)
230                 return -EINVAL;
231         if (enabled)
232                 pdata->irqen |= RTC_AF;
233         else
234                 pdata->irqen &= ~RTC_AF;
235         stk17ta8_rtc_update_alarm(pdata);
236         return 0;
237 }
238 
239 static const struct rtc_class_ops stk17ta8_rtc_ops = {
240         .read_time              = stk17ta8_rtc_read_time,
241         .set_time               = stk17ta8_rtc_set_time,
242         .read_alarm             = stk17ta8_rtc_read_alarm,
243         .set_alarm              = stk17ta8_rtc_set_alarm,
244         .alarm_irq_enable       = stk17ta8_rtc_alarm_irq_enable,
245 };
246 
247 static ssize_t stk17ta8_nvram_read(struct file *filp, struct kobject *kobj,
248                                  struct bin_attribute *attr, char *buf,
249                                  loff_t pos, size_t size)
250 {
251         struct device *dev = container_of(kobj, struct device, kobj);
252         struct platform_device *pdev = to_platform_device(dev);
253         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
254         void __iomem *ioaddr = pdata->ioaddr;
255         ssize_t count;
256 
257         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
258                 *buf++ = readb(ioaddr + pos++);
259         return count;
260 }
261 
262 static ssize_t stk17ta8_nvram_write(struct file *filp, struct kobject *kobj,
263                                   struct bin_attribute *attr, char *buf,
264                                   loff_t pos, size_t size)
265 {
266         struct device *dev = container_of(kobj, struct device, kobj);
267         struct platform_device *pdev = to_platform_device(dev);
268         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
269         void __iomem *ioaddr = pdata->ioaddr;
270         ssize_t count;
271 
272         for (count = 0; size > 0 && pos < RTC_OFFSET; count++, size--)
273                 writeb(*buf++, ioaddr + pos++);
274         return count;
275 }
276 
277 static struct bin_attribute stk17ta8_nvram_attr = {
278         .attr = {
279                 .name = "nvram",
280                 .mode = S_IRUGO | S_IWUSR,
281         },
282         .size = RTC_OFFSET,
283         .read = stk17ta8_nvram_read,
284         .write = stk17ta8_nvram_write,
285 };
286 
287 static int stk17ta8_rtc_probe(struct platform_device *pdev)
288 {
289         struct resource *res;
290         unsigned int cal;
291         unsigned int flags;
292         struct rtc_plat_data *pdata;
293         void __iomem *ioaddr;
294         int ret = 0;
295 
296         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
297         if (!pdata)
298                 return -ENOMEM;
299 
300         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
301         ioaddr = devm_ioremap_resource(&pdev->dev, res);
302         if (IS_ERR(ioaddr))
303                 return PTR_ERR(ioaddr);
304         pdata->ioaddr = ioaddr;
305         pdata->irq = platform_get_irq(pdev, 0);
306 
307         /* turn RTC on if it was not on */
308         cal = readb(ioaddr + RTC_CALIBRATION);
309         if (cal & RTC_STOP) {
310                 cal &= RTC_CAL_MASK;
311                 flags = readb(ioaddr + RTC_FLAGS);
312                 writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
313                 writeb(cal, ioaddr + RTC_CALIBRATION);
314                 writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
315         }
316         if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)
317                 dev_warn(&pdev->dev, "voltage-low detected.\n");
318 
319         spin_lock_init(&pdata->lock);
320         pdata->last_jiffies = jiffies;
321         platform_set_drvdata(pdev, pdata);
322         if (pdata->irq > 0) {
323                 writeb(0, ioaddr + RTC_INTERRUPTS);
324                 if (devm_request_irq(&pdev->dev, pdata->irq,
325                                 stk17ta8_rtc_interrupt,
326                                 IRQF_SHARED,
327                                 pdev->name, pdev) < 0) {
328                         dev_warn(&pdev->dev, "interrupt not available.\n");
329                         pdata->irq = 0;
330                 }
331         }
332 
333         pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
334                                   &stk17ta8_rtc_ops, THIS_MODULE);
335         if (IS_ERR(pdata->rtc))
336                 return PTR_ERR(pdata->rtc);
337 
338         ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
339 
340         return ret;
341 }
342 
343 static int stk17ta8_rtc_remove(struct platform_device *pdev)
344 {
345         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
346 
347         sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
348         if (pdata->irq > 0)
349                 writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
350         return 0;
351 }
352 
353 /* work with hotplug and coldplug */
354 MODULE_ALIAS("platform:stk17ta8");
355 
356 static struct platform_driver stk17ta8_rtc_driver = {
357         .probe          = stk17ta8_rtc_probe,
358         .remove         = stk17ta8_rtc_remove,
359         .driver         = {
360                 .name   = "stk17ta8",
361                 .owner  = THIS_MODULE,
362         },
363 };
364 
365 module_platform_driver(stk17ta8_rtc_driver);
366 
367 MODULE_AUTHOR("Thomas Hommel <thomas.hommel@ge.com>");
368 MODULE_DESCRIPTION("Simtek STK17TA8 RTC driver");
369 MODULE_LICENSE("GPL");
370 MODULE_VERSION(DRV_VERSION);
371 

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