2 * rtc-mrst.c: Driver for Moorestown virtual RTC
4 * (C) Copyright 2009 Intel Corporation
5 * Author: Jacob Pan (jacob.jun.pan@intel.com)
6 * Feng Tang (feng.tang@intel.com)
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; version 2
14 * VRTC is emulated by system controller firmware, the real HW
15 * RTC is located in the PMIC device. SCU FW shadows PMIC RTC
16 * in a memory mapped IO space that is visible to the host IA
19 * This driver is based upon drivers/rtc/rtc-cmos.c
24 * * vRTC only supports binary mode and 24H mode
25 * * vRTC only support PIE and AIE, no UIE, and its PIE only happens
26 * at 23:59:59pm everyday, no support for adjustable frequency
27 * * Alarm function is also limited to hr/min/sec.
30 #include <linux/mod_devicetable.h>
31 #include <linux/platform_device.h>
32 #include <linux/interrupt.h>
33 #include <linux/spinlock.h>
34 #include <linux/kernel.h>
35 #include <linux/module.h>
36 #include <linux/init.h>
37 #include <linux/sfi.h>
39 #include <asm-generic/rtc.h>
40 #include <asm/intel_scu_ipc.h>
42 #include <asm/mrst-vrtc.h>
45 struct rtc_device *rtc;
48 struct resource *iomem;
54 static const char driver_name[] = "rtc_mrst";
56 #define RTC_IRQMASK (RTC_PF | RTC_AF)
58 static inline int is_intr(u8 rtc_intr)
60 if (!(rtc_intr & RTC_IRQF))
62 return rtc_intr & RTC_IRQMASK;
65 static inline unsigned char vrtc_is_updating(void)
70 spin_lock_irqsave(&rtc_lock, flags);
71 uip = (vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP);
72 spin_unlock_irqrestore(&rtc_lock, flags);
77 * rtc_time's year contains the increment over 1900, but vRTC's YEAR
78 * register can't be programmed to value larger than 0x64, so vRTC
79 * driver chose to use 1960 (1970 is UNIX time start point) as the base,
80 * and does the translation at read/write time.
82 * Why not just use 1970 as the offset? it's because using 1960 will
83 * make it consistent in leap year setting for both vrtc and low-level
84 * physical rtc devices.
86 static int mrst_read_time(struct device *dev, struct rtc_time *time)
90 if (vrtc_is_updating())
93 spin_lock_irqsave(&rtc_lock, flags);
94 time->tm_sec = vrtc_cmos_read(RTC_SECONDS);
95 time->tm_min = vrtc_cmos_read(RTC_MINUTES);
96 time->tm_hour = vrtc_cmos_read(RTC_HOURS);
97 time->tm_mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
98 time->tm_mon = vrtc_cmos_read(RTC_MONTH);
99 time->tm_year = vrtc_cmos_read(RTC_YEAR);
100 spin_unlock_irqrestore(&rtc_lock, flags);
102 /* Adjust for the 1960/1900 */
108 static int mrst_set_time(struct device *dev, struct rtc_time *time)
112 unsigned char mon, day, hrs, min, sec;
116 mon = time->tm_mon + 1; /* tm_mon starts at zero */
122 if (yrs < 70 || yrs > 138)
126 spin_lock_irqsave(&rtc_lock, flags);
128 vrtc_cmos_write(yrs, RTC_YEAR);
129 vrtc_cmos_write(mon, RTC_MONTH);
130 vrtc_cmos_write(day, RTC_DAY_OF_MONTH);
131 vrtc_cmos_write(hrs, RTC_HOURS);
132 vrtc_cmos_write(min, RTC_MINUTES);
133 vrtc_cmos_write(sec, RTC_SECONDS);
135 spin_unlock_irqrestore(&rtc_lock, flags);
137 ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETTIME);
141 static int mrst_read_alarm(struct device *dev, struct rtc_wkalrm *t)
143 struct mrst_rtc *mrst = dev_get_drvdata(dev);
144 unsigned char rtc_control;
149 /* Basic alarms only support hour, minute, and seconds fields.
150 * Some also support day and month, for alarms up to a year in
153 t->time.tm_mday = -1;
155 t->time.tm_year = -1;
157 /* vRTC only supports binary mode */
158 spin_lock_irq(&rtc_lock);
159 t->time.tm_sec = vrtc_cmos_read(RTC_SECONDS_ALARM);
160 t->time.tm_min = vrtc_cmos_read(RTC_MINUTES_ALARM);
161 t->time.tm_hour = vrtc_cmos_read(RTC_HOURS_ALARM);
163 rtc_control = vrtc_cmos_read(RTC_CONTROL);
164 spin_unlock_irq(&rtc_lock);
166 t->enabled = !!(rtc_control & RTC_AIE);
172 static void mrst_checkintr(struct mrst_rtc *mrst, unsigned char rtc_control)
174 unsigned char rtc_intr;
177 * NOTE after changing RTC_xIE bits we always read INTR_FLAGS;
178 * allegedly some older rtcs need that to handle irqs properly
180 rtc_intr = vrtc_cmos_read(RTC_INTR_FLAGS);
181 rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
182 if (is_intr(rtc_intr))
183 rtc_update_irq(mrst->rtc, 1, rtc_intr);
186 static void mrst_irq_enable(struct mrst_rtc *mrst, unsigned char mask)
188 unsigned char rtc_control;
191 * Flush any pending IRQ status, notably for update irqs,
192 * before we enable new IRQs
194 rtc_control = vrtc_cmos_read(RTC_CONTROL);
195 mrst_checkintr(mrst, rtc_control);
198 vrtc_cmos_write(rtc_control, RTC_CONTROL);
200 mrst_checkintr(mrst, rtc_control);
203 static void mrst_irq_disable(struct mrst_rtc *mrst, unsigned char mask)
205 unsigned char rtc_control;
207 rtc_control = vrtc_cmos_read(RTC_CONTROL);
208 rtc_control &= ~mask;
209 vrtc_cmos_write(rtc_control, RTC_CONTROL);
210 mrst_checkintr(mrst, rtc_control);
213 static int mrst_set_alarm(struct device *dev, struct rtc_wkalrm *t)
215 struct mrst_rtc *mrst = dev_get_drvdata(dev);
216 unsigned char hrs, min, sec;
222 hrs = t->time.tm_hour;
223 min = t->time.tm_min;
224 sec = t->time.tm_sec;
226 spin_lock_irq(&rtc_lock);
227 /* Next rtc irq must not be from previous alarm setting */
228 mrst_irq_disable(mrst, RTC_AIE);
231 vrtc_cmos_write(hrs, RTC_HOURS_ALARM);
232 vrtc_cmos_write(min, RTC_MINUTES_ALARM);
233 vrtc_cmos_write(sec, RTC_SECONDS_ALARM);
235 spin_unlock_irq(&rtc_lock);
237 ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETALARM);
241 spin_lock_irq(&rtc_lock);
243 mrst_irq_enable(mrst, RTC_AIE);
245 spin_unlock_irq(&rtc_lock);
250 /* Currently, the vRTC doesn't support UIE ON/OFF */
251 static int mrst_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
253 struct mrst_rtc *mrst = dev_get_drvdata(dev);
256 spin_lock_irqsave(&rtc_lock, flags);
258 mrst_irq_enable(mrst, RTC_AIE);
260 mrst_irq_disable(mrst, RTC_AIE);
261 spin_unlock_irqrestore(&rtc_lock, flags);
266 #if defined(CONFIG_RTC_INTF_PROC) || defined(CONFIG_RTC_INTF_PROC_MODULE)
268 static int mrst_procfs(struct device *dev, struct seq_file *seq)
270 unsigned char rtc_control, valid;
272 spin_lock_irq(&rtc_lock);
273 rtc_control = vrtc_cmos_read(RTC_CONTROL);
274 valid = vrtc_cmos_read(RTC_VALID);
275 spin_unlock_irq(&rtc_lock);
277 return seq_printf(seq,
278 "periodic_IRQ\t: %s\n"
281 "periodic_freq\t: daily (not adjustable)\n",
282 (rtc_control & RTC_PIE) ? "on" : "off",
283 (rtc_control & RTC_AIE) ? "on" : "off");
287 #define mrst_procfs NULL
290 static const struct rtc_class_ops mrst_rtc_ops = {
291 .read_time = mrst_read_time,
292 .set_time = mrst_set_time,
293 .read_alarm = mrst_read_alarm,
294 .set_alarm = mrst_set_alarm,
296 .alarm_irq_enable = mrst_rtc_alarm_irq_enable,
299 static struct mrst_rtc mrst_rtc;
302 * When vRTC IRQ is captured by SCU FW, FW will clear the AIE bit in
303 * Reg B, so no need for this driver to clear it
305 static irqreturn_t mrst_rtc_irq(int irq, void *p)
309 spin_lock(&rtc_lock);
310 /* This read will clear all IRQ flags inside Reg C */
311 irqstat = vrtc_cmos_read(RTC_INTR_FLAGS);
312 spin_unlock(&rtc_lock);
314 irqstat &= RTC_IRQMASK | RTC_IRQF;
315 if (is_intr(irqstat)) {
316 rtc_update_irq(p, 1, irqstat);
323 vrtc_mrst_do_probe(struct device *dev, struct resource *iomem, int rtc_irq)
326 unsigned char rtc_control;
328 /* There can be only one ... */
335 iomem = request_mem_region(iomem->start, resource_size(iomem),
338 dev_dbg(dev, "i/o mem already in use.\n");
342 mrst_rtc.irq = rtc_irq;
343 mrst_rtc.iomem = iomem;
345 dev_set_drvdata(dev, &mrst_rtc);
347 mrst_rtc.rtc = rtc_device_register(driver_name, dev,
348 &mrst_rtc_ops, THIS_MODULE);
349 if (IS_ERR(mrst_rtc.rtc)) {
350 retval = PTR_ERR(mrst_rtc.rtc);
354 rename_region(iomem, dev_name(&mrst_rtc.rtc->dev));
356 spin_lock_irq(&rtc_lock);
357 mrst_irq_disable(&mrst_rtc, RTC_PIE | RTC_AIE);
358 rtc_control = vrtc_cmos_read(RTC_CONTROL);
359 spin_unlock_irq(&rtc_lock);
361 if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY)))
362 dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n");
365 retval = request_irq(rtc_irq, mrst_rtc_irq,
366 IRQF_DISABLED, dev_name(&mrst_rtc.rtc->dev),
369 dev_dbg(dev, "IRQ %d is already in use, err %d\n",
374 dev_dbg(dev, "initialised\n");
378 rtc_device_unregister(mrst_rtc.rtc);
380 dev_set_drvdata(dev, NULL);
382 release_mem_region(iomem->start, resource_size(iomem));
383 dev_err(dev, "rtc-mrst: unable to initialise\n");
387 static void rtc_mrst_do_shutdown(void)
389 spin_lock_irq(&rtc_lock);
390 mrst_irq_disable(&mrst_rtc, RTC_IRQMASK);
391 spin_unlock_irq(&rtc_lock);
394 static void __devexit rtc_mrst_do_remove(struct device *dev)
396 struct mrst_rtc *mrst = dev_get_drvdata(dev);
397 struct resource *iomem;
399 rtc_mrst_do_shutdown();
402 free_irq(mrst->irq, mrst->rtc);
404 rtc_device_unregister(mrst->rtc);
408 release_mem_region(iomem->start, resource_size(iomem));
412 dev_set_drvdata(dev, NULL);
416 static int mrst_suspend(struct device *dev, pm_message_t mesg)
418 struct mrst_rtc *mrst = dev_get_drvdata(dev);
421 /* Only the alarm might be a wakeup event source */
422 spin_lock_irq(&rtc_lock);
423 mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL);
424 if (tmp & (RTC_PIE | RTC_AIE)) {
427 if (device_may_wakeup(dev))
428 mask = RTC_IRQMASK & ~RTC_AIE;
432 vrtc_cmos_write(tmp, RTC_CONTROL);
434 mrst_checkintr(mrst, tmp);
436 spin_unlock_irq(&rtc_lock);
439 mrst->enabled_wake = 1;
440 enable_irq_wake(mrst->irq);
443 dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n",
444 (tmp & RTC_AIE) ? ", alarm may wake" : "",
451 * We want RTC alarms to wake us from the deep power saving state
453 static inline int mrst_poweroff(struct device *dev)
455 return mrst_suspend(dev, PMSG_HIBERNATE);
458 static int mrst_resume(struct device *dev)
460 struct mrst_rtc *mrst = dev_get_drvdata(dev);
461 unsigned char tmp = mrst->suspend_ctrl;
463 /* Re-enable any irqs previously active */
464 if (tmp & RTC_IRQMASK) {
467 if (mrst->enabled_wake) {
468 disable_irq_wake(mrst->irq);
469 mrst->enabled_wake = 0;
472 spin_lock_irq(&rtc_lock);
474 vrtc_cmos_write(tmp, RTC_CONTROL);
476 mask = vrtc_cmos_read(RTC_INTR_FLAGS);
477 mask &= (tmp & RTC_IRQMASK) | RTC_IRQF;
481 rtc_update_irq(mrst->rtc, 1, mask);
483 } while (mask & RTC_AIE);
484 spin_unlock_irq(&rtc_lock);
487 dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp);
493 #define mrst_suspend NULL
494 #define mrst_resume NULL
496 static inline int mrst_poweroff(struct device *dev)
503 static int __devinit vrtc_mrst_platform_probe(struct platform_device *pdev)
505 return vrtc_mrst_do_probe(&pdev->dev,
506 platform_get_resource(pdev, IORESOURCE_MEM, 0),
507 platform_get_irq(pdev, 0));
510 static int __devexit vrtc_mrst_platform_remove(struct platform_device *pdev)
512 rtc_mrst_do_remove(&pdev->dev);
516 static void vrtc_mrst_platform_shutdown(struct platform_device *pdev)
518 if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev))
521 rtc_mrst_do_shutdown();
524 MODULE_ALIAS("platform:vrtc_mrst");
526 static struct platform_driver vrtc_mrst_platform_driver = {
527 .probe = vrtc_mrst_platform_probe,
528 .remove = __devexit_p(vrtc_mrst_platform_remove),
529 .shutdown = vrtc_mrst_platform_shutdown,
531 .name = (char *) driver_name,
532 .suspend = mrst_suspend,
533 .resume = mrst_resume,
537 static int __init vrtc_mrst_init(void)
539 return platform_driver_register(&vrtc_mrst_platform_driver);
542 static void __exit vrtc_mrst_exit(void)
544 platform_driver_unregister(&vrtc_mrst_platform_driver);
547 module_init(vrtc_mrst_init);
548 module_exit(vrtc_mrst_exit);
550 MODULE_AUTHOR("Jacob Pan; Feng Tang");
551 MODULE_DESCRIPTION("Driver for Moorestown virtual RTC");
552 MODULE_LICENSE("GPL");