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521 lines
12 KiB
521 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* rtc-mrst.c: Driver for Moorestown virtual RTC |
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* |
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* (C) Copyright 2009 Intel Corporation |
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* Author: Jacob Pan ([email protected]) |
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* Feng Tang ([email protected]) |
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* |
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* Note: |
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* VRTC is emulated by system controller firmware, the real HW |
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* RTC is located in the PMIC device. SCU FW shadows PMIC RTC |
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* in a memory mapped IO space that is visible to the host IA |
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* processor. |
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* |
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* This driver is based upon drivers/rtc/rtc-cmos.c |
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*/ |
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|
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/* |
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* Note: |
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* * vRTC only supports binary mode and 24H mode |
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* * vRTC only support PIE and AIE, no UIE, and its PIE only happens |
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* at 23:59:59pm everyday, no support for adjustable frequency |
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* * Alarm function is also limited to hr/min/sec. |
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*/ |
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#include <linux/mod_devicetable.h> |
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#include <linux/platform_device.h> |
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#include <linux/interrupt.h> |
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#include <linux/spinlock.h> |
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#include <linux/kernel.h> |
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#include <linux/mc146818rtc.h> |
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#include <linux/module.h> |
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#include <linux/init.h> |
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#include <linux/sfi.h> |
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#include <asm/intel_scu_ipc.h> |
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#include <asm/intel-mid.h> |
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#include <asm/intel_mid_vrtc.h> |
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struct mrst_rtc { |
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struct rtc_device *rtc; |
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struct device *dev; |
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int irq; |
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u8 enabled_wake; |
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u8 suspend_ctrl; |
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}; |
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static const char driver_name[] = "rtc_mrst"; |
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#define RTC_IRQMASK (RTC_PF | RTC_AF) |
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static inline int is_intr(u8 rtc_intr) |
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{ |
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if (!(rtc_intr & RTC_IRQF)) |
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return 0; |
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return rtc_intr & RTC_IRQMASK; |
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} |
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static inline unsigned char vrtc_is_updating(void) |
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{ |
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unsigned char uip; |
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unsigned long flags; |
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spin_lock_irqsave(&rtc_lock, flags); |
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uip = (vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP); |
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spin_unlock_irqrestore(&rtc_lock, flags); |
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return uip; |
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} |
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/* |
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* rtc_time's year contains the increment over 1900, but vRTC's YEAR |
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* register can't be programmed to value larger than 0x64, so vRTC |
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* driver chose to use 1972 (1970 is UNIX time start point) as the base, |
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* and does the translation at read/write time. |
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* |
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* Why not just use 1970 as the offset? it's because using 1972 will |
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* make it consistent in leap year setting for both vrtc and low-level |
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* physical rtc devices. Then why not use 1960 as the offset? If we use |
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* 1960, for a device's first use, its YEAR register is 0 and the system |
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* year will be parsed as 1960 which is not a valid UNIX time and will |
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* cause many applications to fail mysteriously. |
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*/ |
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static int mrst_read_time(struct device *dev, struct rtc_time *time) |
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{ |
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unsigned long flags; |
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if (vrtc_is_updating()) |
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msleep(20); |
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spin_lock_irqsave(&rtc_lock, flags); |
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time->tm_sec = vrtc_cmos_read(RTC_SECONDS); |
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time->tm_min = vrtc_cmos_read(RTC_MINUTES); |
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time->tm_hour = vrtc_cmos_read(RTC_HOURS); |
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time->tm_mday = vrtc_cmos_read(RTC_DAY_OF_MONTH); |
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time->tm_mon = vrtc_cmos_read(RTC_MONTH); |
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time->tm_year = vrtc_cmos_read(RTC_YEAR); |
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spin_unlock_irqrestore(&rtc_lock, flags); |
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/* Adjust for the 1972/1900 */ |
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time->tm_year += 72; |
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time->tm_mon--; |
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return 0; |
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} |
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static int mrst_set_time(struct device *dev, struct rtc_time *time) |
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{ |
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int ret; |
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unsigned long flags; |
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unsigned char mon, day, hrs, min, sec; |
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unsigned int yrs; |
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yrs = time->tm_year; |
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mon = time->tm_mon + 1; /* tm_mon starts at zero */ |
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day = time->tm_mday; |
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hrs = time->tm_hour; |
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min = time->tm_min; |
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sec = time->tm_sec; |
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if (yrs < 72 || yrs > 172) |
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return -EINVAL; |
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yrs -= 72; |
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spin_lock_irqsave(&rtc_lock, flags); |
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vrtc_cmos_write(yrs, RTC_YEAR); |
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vrtc_cmos_write(mon, RTC_MONTH); |
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vrtc_cmos_write(day, RTC_DAY_OF_MONTH); |
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vrtc_cmos_write(hrs, RTC_HOURS); |
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vrtc_cmos_write(min, RTC_MINUTES); |
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vrtc_cmos_write(sec, RTC_SECONDS); |
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spin_unlock_irqrestore(&rtc_lock, flags); |
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ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETTIME); |
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return ret; |
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} |
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static int mrst_read_alarm(struct device *dev, struct rtc_wkalrm *t) |
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{ |
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struct mrst_rtc *mrst = dev_get_drvdata(dev); |
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unsigned char rtc_control; |
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if (mrst->irq <= 0) |
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return -EIO; |
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/* vRTC only supports binary mode */ |
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spin_lock_irq(&rtc_lock); |
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t->time.tm_sec = vrtc_cmos_read(RTC_SECONDS_ALARM); |
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t->time.tm_min = vrtc_cmos_read(RTC_MINUTES_ALARM); |
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t->time.tm_hour = vrtc_cmos_read(RTC_HOURS_ALARM); |
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rtc_control = vrtc_cmos_read(RTC_CONTROL); |
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spin_unlock_irq(&rtc_lock); |
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t->enabled = !!(rtc_control & RTC_AIE); |
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t->pending = 0; |
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return 0; |
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} |
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static void mrst_checkintr(struct mrst_rtc *mrst, unsigned char rtc_control) |
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{ |
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unsigned char rtc_intr; |
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/* |
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* NOTE after changing RTC_xIE bits we always read INTR_FLAGS; |
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* allegedly some older rtcs need that to handle irqs properly |
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*/ |
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rtc_intr = vrtc_cmos_read(RTC_INTR_FLAGS); |
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rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF; |
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if (is_intr(rtc_intr)) |
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rtc_update_irq(mrst->rtc, 1, rtc_intr); |
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} |
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static void mrst_irq_enable(struct mrst_rtc *mrst, unsigned char mask) |
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{ |
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unsigned char rtc_control; |
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/* |
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* Flush any pending IRQ status, notably for update irqs, |
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* before we enable new IRQs |
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*/ |
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rtc_control = vrtc_cmos_read(RTC_CONTROL); |
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mrst_checkintr(mrst, rtc_control); |
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rtc_control |= mask; |
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vrtc_cmos_write(rtc_control, RTC_CONTROL); |
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mrst_checkintr(mrst, rtc_control); |
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} |
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static void mrst_irq_disable(struct mrst_rtc *mrst, unsigned char mask) |
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{ |
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unsigned char rtc_control; |
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rtc_control = vrtc_cmos_read(RTC_CONTROL); |
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rtc_control &= ~mask; |
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vrtc_cmos_write(rtc_control, RTC_CONTROL); |
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mrst_checkintr(mrst, rtc_control); |
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} |
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static int mrst_set_alarm(struct device *dev, struct rtc_wkalrm *t) |
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{ |
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struct mrst_rtc *mrst = dev_get_drvdata(dev); |
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unsigned char hrs, min, sec; |
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int ret = 0; |
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if (!mrst->irq) |
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return -EIO; |
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hrs = t->time.tm_hour; |
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min = t->time.tm_min; |
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sec = t->time.tm_sec; |
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spin_lock_irq(&rtc_lock); |
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/* Next rtc irq must not be from previous alarm setting */ |
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mrst_irq_disable(mrst, RTC_AIE); |
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/* Update alarm */ |
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vrtc_cmos_write(hrs, RTC_HOURS_ALARM); |
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vrtc_cmos_write(min, RTC_MINUTES_ALARM); |
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vrtc_cmos_write(sec, RTC_SECONDS_ALARM); |
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spin_unlock_irq(&rtc_lock); |
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ret = intel_scu_ipc_simple_command(IPCMSG_VRTC, IPC_CMD_VRTC_SETALARM); |
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if (ret) |
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return ret; |
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spin_lock_irq(&rtc_lock); |
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if (t->enabled) |
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mrst_irq_enable(mrst, RTC_AIE); |
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spin_unlock_irq(&rtc_lock); |
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return 0; |
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} |
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/* Currently, the vRTC doesn't support UIE ON/OFF */ |
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static int mrst_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) |
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{ |
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struct mrst_rtc *mrst = dev_get_drvdata(dev); |
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unsigned long flags; |
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spin_lock_irqsave(&rtc_lock, flags); |
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if (enabled) |
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mrst_irq_enable(mrst, RTC_AIE); |
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else |
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mrst_irq_disable(mrst, RTC_AIE); |
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spin_unlock_irqrestore(&rtc_lock, flags); |
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return 0; |
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} |
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#if IS_ENABLED(CONFIG_RTC_INTF_PROC) |
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static int mrst_procfs(struct device *dev, struct seq_file *seq) |
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{ |
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unsigned char rtc_control; |
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spin_lock_irq(&rtc_lock); |
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rtc_control = vrtc_cmos_read(RTC_CONTROL); |
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spin_unlock_irq(&rtc_lock); |
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seq_printf(seq, |
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"periodic_IRQ\t: %s\n" |
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"alarm\t\t: %s\n" |
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"BCD\t\t: no\n" |
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"periodic_freq\t: daily (not adjustable)\n", |
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(rtc_control & RTC_PIE) ? "on" : "off", |
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(rtc_control & RTC_AIE) ? "on" : "off"); |
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return 0; |
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} |
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#else |
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#define mrst_procfs NULL |
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#endif |
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static const struct rtc_class_ops mrst_rtc_ops = { |
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.read_time = mrst_read_time, |
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.set_time = mrst_set_time, |
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.read_alarm = mrst_read_alarm, |
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.set_alarm = mrst_set_alarm, |
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.proc = mrst_procfs, |
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.alarm_irq_enable = mrst_rtc_alarm_irq_enable, |
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}; |
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static struct mrst_rtc mrst_rtc; |
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/* |
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* When vRTC IRQ is captured by SCU FW, FW will clear the AIE bit in |
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* Reg B, so no need for this driver to clear it |
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*/ |
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static irqreturn_t mrst_rtc_irq(int irq, void *p) |
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{ |
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u8 irqstat; |
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spin_lock(&rtc_lock); |
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/* This read will clear all IRQ flags inside Reg C */ |
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irqstat = vrtc_cmos_read(RTC_INTR_FLAGS); |
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spin_unlock(&rtc_lock); |
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irqstat &= RTC_IRQMASK | RTC_IRQF; |
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if (is_intr(irqstat)) { |
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rtc_update_irq(p, 1, irqstat); |
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return IRQ_HANDLED; |
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} |
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return IRQ_NONE; |
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} |
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static int vrtc_mrst_do_probe(struct device *dev, struct resource *iomem, |
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int rtc_irq) |
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{ |
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int retval = 0; |
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unsigned char rtc_control; |
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/* There can be only one ... */ |
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if (mrst_rtc.dev) |
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return -EBUSY; |
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if (!iomem) |
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return -ENODEV; |
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iomem = devm_request_mem_region(dev, iomem->start, resource_size(iomem), |
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driver_name); |
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if (!iomem) { |
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dev_dbg(dev, "i/o mem already in use.\n"); |
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return -EBUSY; |
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} |
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mrst_rtc.irq = rtc_irq; |
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mrst_rtc.dev = dev; |
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dev_set_drvdata(dev, &mrst_rtc); |
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mrst_rtc.rtc = devm_rtc_allocate_device(dev); |
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if (IS_ERR(mrst_rtc.rtc)) |
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return PTR_ERR(mrst_rtc.rtc); |
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mrst_rtc.rtc->ops = &mrst_rtc_ops; |
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rename_region(iomem, dev_name(&mrst_rtc.rtc->dev)); |
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spin_lock_irq(&rtc_lock); |
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mrst_irq_disable(&mrst_rtc, RTC_PIE | RTC_AIE); |
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rtc_control = vrtc_cmos_read(RTC_CONTROL); |
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spin_unlock_irq(&rtc_lock); |
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if (!(rtc_control & RTC_24H) || (rtc_control & (RTC_DM_BINARY))) |
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dev_dbg(dev, "TODO: support more than 24-hr BCD mode\n"); |
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if (rtc_irq) { |
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retval = devm_request_irq(dev, rtc_irq, mrst_rtc_irq, |
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0, dev_name(&mrst_rtc.rtc->dev), |
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mrst_rtc.rtc); |
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if (retval < 0) { |
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dev_dbg(dev, "IRQ %d is already in use, err %d\n", |
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rtc_irq, retval); |
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goto cleanup0; |
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} |
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} |
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retval = rtc_register_device(mrst_rtc.rtc); |
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if (retval) |
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goto cleanup0; |
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dev_dbg(dev, "initialised\n"); |
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return 0; |
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cleanup0: |
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mrst_rtc.dev = NULL; |
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dev_err(dev, "rtc-mrst: unable to initialise\n"); |
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return retval; |
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} |
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static void rtc_mrst_do_shutdown(void) |
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{ |
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spin_lock_irq(&rtc_lock); |
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mrst_irq_disable(&mrst_rtc, RTC_IRQMASK); |
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spin_unlock_irq(&rtc_lock); |
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} |
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static void rtc_mrst_do_remove(struct device *dev) |
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{ |
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struct mrst_rtc *mrst = dev_get_drvdata(dev); |
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rtc_mrst_do_shutdown(); |
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mrst->rtc = NULL; |
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mrst->dev = NULL; |
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} |
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#ifdef CONFIG_PM_SLEEP |
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static int mrst_suspend(struct device *dev) |
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{ |
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struct mrst_rtc *mrst = dev_get_drvdata(dev); |
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unsigned char tmp; |
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/* Only the alarm might be a wakeup event source */ |
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spin_lock_irq(&rtc_lock); |
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mrst->suspend_ctrl = tmp = vrtc_cmos_read(RTC_CONTROL); |
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if (tmp & (RTC_PIE | RTC_AIE)) { |
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unsigned char mask; |
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if (device_may_wakeup(dev)) |
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mask = RTC_IRQMASK & ~RTC_AIE; |
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else |
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mask = RTC_IRQMASK; |
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tmp &= ~mask; |
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vrtc_cmos_write(tmp, RTC_CONTROL); |
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mrst_checkintr(mrst, tmp); |
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} |
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spin_unlock_irq(&rtc_lock); |
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if (tmp & RTC_AIE) { |
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mrst->enabled_wake = 1; |
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enable_irq_wake(mrst->irq); |
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} |
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dev_dbg(&mrst_rtc.rtc->dev, "suspend%s, ctrl %02x\n", |
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(tmp & RTC_AIE) ? ", alarm may wake" : "", |
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tmp); |
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return 0; |
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} |
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/* |
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* We want RTC alarms to wake us from the deep power saving state |
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*/ |
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static inline int mrst_poweroff(struct device *dev) |
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{ |
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return mrst_suspend(dev); |
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} |
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static int mrst_resume(struct device *dev) |
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{ |
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struct mrst_rtc *mrst = dev_get_drvdata(dev); |
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unsigned char tmp = mrst->suspend_ctrl; |
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/* Re-enable any irqs previously active */ |
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if (tmp & RTC_IRQMASK) { |
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unsigned char mask; |
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if (mrst->enabled_wake) { |
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disable_irq_wake(mrst->irq); |
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mrst->enabled_wake = 0; |
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} |
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spin_lock_irq(&rtc_lock); |
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do { |
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vrtc_cmos_write(tmp, RTC_CONTROL); |
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mask = vrtc_cmos_read(RTC_INTR_FLAGS); |
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mask &= (tmp & RTC_IRQMASK) | RTC_IRQF; |
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if (!is_intr(mask)) |
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break; |
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rtc_update_irq(mrst->rtc, 1, mask); |
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tmp &= ~RTC_AIE; |
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} while (mask & RTC_AIE); |
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spin_unlock_irq(&rtc_lock); |
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} |
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dev_dbg(&mrst_rtc.rtc->dev, "resume, ctrl %02x\n", tmp); |
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return 0; |
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} |
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static SIMPLE_DEV_PM_OPS(mrst_pm_ops, mrst_suspend, mrst_resume); |
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#define MRST_PM_OPS (&mrst_pm_ops) |
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#else |
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#define MRST_PM_OPS NULL |
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static inline int mrst_poweroff(struct device *dev) |
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{ |
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return -ENOSYS; |
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} |
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#endif |
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static int vrtc_mrst_platform_probe(struct platform_device *pdev) |
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{ |
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return vrtc_mrst_do_probe(&pdev->dev, |
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platform_get_resource(pdev, IORESOURCE_MEM, 0), |
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platform_get_irq(pdev, 0)); |
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} |
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static int vrtc_mrst_platform_remove(struct platform_device *pdev) |
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{ |
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rtc_mrst_do_remove(&pdev->dev); |
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return 0; |
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} |
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static void vrtc_mrst_platform_shutdown(struct platform_device *pdev) |
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{ |
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if (system_state == SYSTEM_POWER_OFF && !mrst_poweroff(&pdev->dev)) |
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return; |
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rtc_mrst_do_shutdown(); |
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} |
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MODULE_ALIAS("platform:vrtc_mrst"); |
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static struct platform_driver vrtc_mrst_platform_driver = { |
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.probe = vrtc_mrst_platform_probe, |
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.remove = vrtc_mrst_platform_remove, |
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.shutdown = vrtc_mrst_platform_shutdown, |
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.driver = { |
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.name = driver_name, |
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.pm = MRST_PM_OPS, |
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} |
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}; |
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module_platform_driver(vrtc_mrst_platform_driver); |
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MODULE_AUTHOR("Jacob Pan; Feng Tang"); |
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MODULE_DESCRIPTION("Driver for Moorestown virtual RTC"); |
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MODULE_LICENSE("GPL");
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