462 lines
11 KiB
C
462 lines
11 KiB
C
/*
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* SiRFSoC Real Time Clock interface for Linux
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*
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* Copyright (c) 2013 Cambridge Silicon Radio Limited, a CSR plc group company.
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*
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* Licensed under GPLv2 or later.
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*/
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#include <linux/module.h>
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#include <linux/err.h>
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#include <linux/rtc.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/regmap.h>
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#include <linux/rtc/sirfsoc_rtciobrg.h>
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#define RTC_CN 0x00
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#define RTC_ALARM0 0x04
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#define RTC_ALARM1 0x18
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#define RTC_STATUS 0x08
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#define RTC_SW_VALUE 0x40
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#define SIRFSOC_RTC_AL1E (1<<6)
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#define SIRFSOC_RTC_AL1 (1<<4)
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#define SIRFSOC_RTC_HZE (1<<3)
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#define SIRFSOC_RTC_AL0E (1<<2)
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#define SIRFSOC_RTC_HZ (1<<1)
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#define SIRFSOC_RTC_AL0 (1<<0)
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#define RTC_DIV 0x0c
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#define RTC_DEEP_CTRL 0x14
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#define RTC_CLOCK_SWITCH 0x1c
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#define SIRFSOC_RTC_CLK 0x03 /* others are reserved */
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/* Refer to RTC DIV switch */
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#define RTC_HZ 16
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/* This macro is also defined in arch/arm/plat-sirfsoc/cpu.c */
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#define RTC_SHIFT 4
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#define INTR_SYSRTC_CN 0x48
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struct sirfsoc_rtc_drv {
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struct rtc_device *rtc;
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u32 rtc_base;
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u32 irq;
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unsigned irq_wake;
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/* Overflow for every 8 years extra time */
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u32 overflow_rtc;
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spinlock_t lock;
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struct regmap *regmap;
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#ifdef CONFIG_PM
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u32 saved_counter;
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u32 saved_overflow_rtc;
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#endif
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};
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static u32 sirfsoc_rtc_readl(struct sirfsoc_rtc_drv *rtcdrv, u32 offset)
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{
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u32 val;
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regmap_read(rtcdrv->regmap, rtcdrv->rtc_base + offset, &val);
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return val;
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}
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static void sirfsoc_rtc_writel(struct sirfsoc_rtc_drv *rtcdrv,
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u32 offset, u32 val)
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{
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regmap_write(rtcdrv->regmap, rtcdrv->rtc_base + offset, val);
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}
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static int sirfsoc_rtc_read_alarm(struct device *dev,
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struct rtc_wkalrm *alrm)
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{
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unsigned long rtc_alarm, rtc_count;
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struct sirfsoc_rtc_drv *rtcdrv;
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rtcdrv = dev_get_drvdata(dev);
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spin_lock_irq(&rtcdrv->lock);
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rtc_count = sirfsoc_rtc_readl(rtcdrv, RTC_CN);
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rtc_alarm = sirfsoc_rtc_readl(rtcdrv, RTC_ALARM0);
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memset(alrm, 0, sizeof(struct rtc_wkalrm));
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/*
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* assume alarm interval not beyond one round counter overflow_rtc:
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* 0->0xffffffff
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*/
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/* if alarm is in next overflow cycle */
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if (rtc_count > rtc_alarm)
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rtc_time_to_tm((rtcdrv->overflow_rtc + 1)
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<< (BITS_PER_LONG - RTC_SHIFT)
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| rtc_alarm >> RTC_SHIFT, &(alrm->time));
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else
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rtc_time_to_tm(rtcdrv->overflow_rtc
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<< (BITS_PER_LONG - RTC_SHIFT)
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| rtc_alarm >> RTC_SHIFT, &(alrm->time));
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if (sirfsoc_rtc_readl(rtcdrv, RTC_STATUS) & SIRFSOC_RTC_AL0E)
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alrm->enabled = 1;
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spin_unlock_irq(&rtcdrv->lock);
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return 0;
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}
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static int sirfsoc_rtc_set_alarm(struct device *dev,
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struct rtc_wkalrm *alrm)
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{
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unsigned long rtc_status_reg, rtc_alarm;
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struct sirfsoc_rtc_drv *rtcdrv;
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rtcdrv = dev_get_drvdata(dev);
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if (alrm->enabled) {
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rtc_tm_to_time(&(alrm->time), &rtc_alarm);
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spin_lock_irq(&rtcdrv->lock);
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rtc_status_reg = sirfsoc_rtc_readl(rtcdrv, RTC_STATUS);
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if (rtc_status_reg & SIRFSOC_RTC_AL0E) {
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/*
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* An ongoing alarm in progress - ingore it and not
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* to return EBUSY
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*/
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dev_info(dev, "An old alarm was set, will be replaced by a new one\n");
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}
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sirfsoc_rtc_writel(rtcdrv, RTC_ALARM0, rtc_alarm << RTC_SHIFT);
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rtc_status_reg &= ~0x07; /* mask out the lower status bits */
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/*
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* This bit RTC_AL sets it as a wake-up source for Sleep Mode
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* Writing 1 into this bit will clear it
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*/
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rtc_status_reg |= SIRFSOC_RTC_AL0;
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/* enable the RTC alarm interrupt */
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rtc_status_reg |= SIRFSOC_RTC_AL0E;
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sirfsoc_rtc_writel(rtcdrv, RTC_STATUS, rtc_status_reg);
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spin_unlock_irq(&rtcdrv->lock);
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} else {
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/*
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* if this function was called with enabled=0
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* then it could mean that the application is
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* trying to cancel an ongoing alarm
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*/
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spin_lock_irq(&rtcdrv->lock);
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rtc_status_reg = sirfsoc_rtc_readl(rtcdrv, RTC_STATUS);
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if (rtc_status_reg & SIRFSOC_RTC_AL0E) {
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/* clear the RTC status register's alarm bit */
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rtc_status_reg &= ~0x07;
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/* write 1 into SIRFSOC_RTC_AL0 to force a clear */
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rtc_status_reg |= (SIRFSOC_RTC_AL0);
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/* Clear the Alarm enable bit */
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rtc_status_reg &= ~(SIRFSOC_RTC_AL0E);
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sirfsoc_rtc_writel(rtcdrv, RTC_STATUS,
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rtc_status_reg);
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}
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spin_unlock_irq(&rtcdrv->lock);
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}
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return 0;
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}
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static int sirfsoc_rtc_read_time(struct device *dev,
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struct rtc_time *tm)
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{
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unsigned long tmp_rtc = 0;
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struct sirfsoc_rtc_drv *rtcdrv;
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rtcdrv = dev_get_drvdata(dev);
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/*
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* This patch is taken from WinCE - Need to validate this for
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* correctness. To work around sirfsoc RTC counter double sync logic
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* fail, read several times to make sure get stable value.
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*/
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do {
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tmp_rtc = sirfsoc_rtc_readl(rtcdrv, RTC_CN);
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cpu_relax();
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} while (tmp_rtc != sirfsoc_rtc_readl(rtcdrv, RTC_CN));
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rtc_time_to_tm(rtcdrv->overflow_rtc << (BITS_PER_LONG - RTC_SHIFT) |
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tmp_rtc >> RTC_SHIFT, tm);
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return 0;
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}
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static int sirfsoc_rtc_set_time(struct device *dev,
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struct rtc_time *tm)
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{
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unsigned long rtc_time;
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struct sirfsoc_rtc_drv *rtcdrv;
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rtcdrv = dev_get_drvdata(dev);
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rtc_tm_to_time(tm, &rtc_time);
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rtcdrv->overflow_rtc = rtc_time >> (BITS_PER_LONG - RTC_SHIFT);
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sirfsoc_rtc_writel(rtcdrv, RTC_SW_VALUE, rtcdrv->overflow_rtc);
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sirfsoc_rtc_writel(rtcdrv, RTC_CN, rtc_time << RTC_SHIFT);
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return 0;
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}
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static int sirfsoc_rtc_alarm_irq_enable(struct device *dev,
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unsigned int enabled)
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{
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unsigned long rtc_status_reg = 0x0;
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struct sirfsoc_rtc_drv *rtcdrv;
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rtcdrv = dev_get_drvdata(dev);
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spin_lock_irq(&rtcdrv->lock);
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rtc_status_reg = sirfsoc_rtc_readl(rtcdrv, RTC_STATUS);
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if (enabled)
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rtc_status_reg |= SIRFSOC_RTC_AL0E;
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else
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rtc_status_reg &= ~SIRFSOC_RTC_AL0E;
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sirfsoc_rtc_writel(rtcdrv, RTC_STATUS, rtc_status_reg);
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spin_unlock_irq(&rtcdrv->lock);
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return 0;
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}
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static const struct rtc_class_ops sirfsoc_rtc_ops = {
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.read_time = sirfsoc_rtc_read_time,
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.set_time = sirfsoc_rtc_set_time,
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.read_alarm = sirfsoc_rtc_read_alarm,
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.set_alarm = sirfsoc_rtc_set_alarm,
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.alarm_irq_enable = sirfsoc_rtc_alarm_irq_enable
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};
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static irqreturn_t sirfsoc_rtc_irq_handler(int irq, void *pdata)
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{
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struct sirfsoc_rtc_drv *rtcdrv = pdata;
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unsigned long rtc_status_reg = 0x0;
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unsigned long events = 0x0;
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spin_lock(&rtcdrv->lock);
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rtc_status_reg = sirfsoc_rtc_readl(rtcdrv, RTC_STATUS);
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/* this bit will be set ONLY if an alarm was active
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* and it expired NOW
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* So this is being used as an ASSERT
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*/
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if (rtc_status_reg & SIRFSOC_RTC_AL0) {
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/*
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* clear the RTC status register's alarm bit
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* mask out the lower status bits
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*/
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rtc_status_reg &= ~0x07;
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/* write 1 into SIRFSOC_RTC_AL0 to ACK the alarm interrupt */
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rtc_status_reg |= (SIRFSOC_RTC_AL0);
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/* Clear the Alarm enable bit */
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rtc_status_reg &= ~(SIRFSOC_RTC_AL0E);
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}
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sirfsoc_rtc_writel(rtcdrv, RTC_STATUS, rtc_status_reg);
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spin_unlock(&rtcdrv->lock);
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/* this should wake up any apps polling/waiting on the read
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* after setting the alarm
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*/
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events |= RTC_IRQF | RTC_AF;
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rtc_update_irq(rtcdrv->rtc, 1, events);
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return IRQ_HANDLED;
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}
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static const struct of_device_id sirfsoc_rtc_of_match[] = {
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{ .compatible = "sirf,prima2-sysrtc"},
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{},
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};
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const struct regmap_config sysrtc_regmap_config = {
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.reg_bits = 32,
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.val_bits = 32,
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.fast_io = true,
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};
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MODULE_DEVICE_TABLE(of, sirfsoc_rtc_of_match);
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static int sirfsoc_rtc_probe(struct platform_device *pdev)
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{
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int err;
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unsigned long rtc_div;
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struct sirfsoc_rtc_drv *rtcdrv;
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struct device_node *np = pdev->dev.of_node;
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rtcdrv = devm_kzalloc(&pdev->dev,
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sizeof(struct sirfsoc_rtc_drv), GFP_KERNEL);
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if (rtcdrv == NULL)
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return -ENOMEM;
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spin_lock_init(&rtcdrv->lock);
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err = of_property_read_u32(np, "reg", &rtcdrv->rtc_base);
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if (err) {
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dev_err(&pdev->dev, "unable to find base address of rtc node in dtb\n");
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return err;
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}
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platform_set_drvdata(pdev, rtcdrv);
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/* Register rtc alarm as a wakeup source */
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device_init_wakeup(&pdev->dev, 1);
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rtcdrv->regmap = devm_regmap_init_iobg(&pdev->dev,
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&sysrtc_regmap_config);
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if (IS_ERR(rtcdrv->regmap)) {
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err = PTR_ERR(rtcdrv->regmap);
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dev_err(&pdev->dev, "Failed to allocate register map: %d\n",
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err);
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return err;
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}
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/*
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* Set SYS_RTC counter in RTC_HZ HZ Units
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* We are using 32K RTC crystal (32768 / RTC_HZ / 2) -1
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* If 16HZ, therefore RTC_DIV = 1023;
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*/
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rtc_div = ((32768 / RTC_HZ) / 2) - 1;
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sirfsoc_rtc_writel(rtcdrv, RTC_DIV, rtc_div);
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/* 0x3 -> RTC_CLK */
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sirfsoc_rtc_writel(rtcdrv, RTC_CLOCK_SWITCH, SIRFSOC_RTC_CLK);
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/* reset SYS RTC ALARM0 */
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sirfsoc_rtc_writel(rtcdrv, RTC_ALARM0, 0x0);
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/* reset SYS RTC ALARM1 */
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sirfsoc_rtc_writel(rtcdrv, RTC_ALARM1, 0x0);
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/* Restore RTC Overflow From Register After Command Reboot */
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rtcdrv->overflow_rtc =
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sirfsoc_rtc_readl(rtcdrv, RTC_SW_VALUE);
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rtcdrv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
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&sirfsoc_rtc_ops, THIS_MODULE);
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if (IS_ERR(rtcdrv->rtc)) {
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err = PTR_ERR(rtcdrv->rtc);
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dev_err(&pdev->dev, "can't register RTC device\n");
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return err;
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}
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rtcdrv->irq = platform_get_irq(pdev, 0);
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err = devm_request_irq(
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&pdev->dev,
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rtcdrv->irq,
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sirfsoc_rtc_irq_handler,
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IRQF_SHARED,
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pdev->name,
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rtcdrv);
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if (err) {
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dev_err(&pdev->dev, "Unable to register for the SiRF SOC RTC IRQ\n");
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return err;
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}
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return 0;
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}
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static int sirfsoc_rtc_remove(struct platform_device *pdev)
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{
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device_init_wakeup(&pdev->dev, 0);
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return 0;
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}
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#ifdef CONFIG_PM_SLEEP
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static int sirfsoc_rtc_suspend(struct device *dev)
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{
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struct sirfsoc_rtc_drv *rtcdrv = dev_get_drvdata(dev);
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rtcdrv->overflow_rtc =
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sirfsoc_rtc_readl(rtcdrv, RTC_SW_VALUE);
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rtcdrv->saved_counter =
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sirfsoc_rtc_readl(rtcdrv, RTC_CN);
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rtcdrv->saved_overflow_rtc = rtcdrv->overflow_rtc;
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if (device_may_wakeup(dev) && !enable_irq_wake(rtcdrv->irq))
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rtcdrv->irq_wake = 1;
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return 0;
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}
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static int sirfsoc_rtc_resume(struct device *dev)
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{
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u32 tmp;
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struct sirfsoc_rtc_drv *rtcdrv = dev_get_drvdata(dev);
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/*
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* if resume from snapshot and the rtc power is lost,
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* restroe the rtc settings
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*/
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if (SIRFSOC_RTC_CLK != sirfsoc_rtc_readl(rtcdrv, RTC_CLOCK_SWITCH)) {
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u32 rtc_div;
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/* 0x3 -> RTC_CLK */
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sirfsoc_rtc_writel(rtcdrv, RTC_CLOCK_SWITCH, SIRFSOC_RTC_CLK);
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/*
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* Set SYS_RTC counter in RTC_HZ HZ Units
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* We are using 32K RTC crystal (32768 / RTC_HZ / 2) -1
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* If 16HZ, therefore RTC_DIV = 1023;
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*/
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rtc_div = ((32768 / RTC_HZ) / 2) - 1;
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sirfsoc_rtc_writel(rtcdrv, RTC_DIV, rtc_div);
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/* reset SYS RTC ALARM0 */
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sirfsoc_rtc_writel(rtcdrv, RTC_ALARM0, 0x0);
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/* reset SYS RTC ALARM1 */
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sirfsoc_rtc_writel(rtcdrv, RTC_ALARM1, 0x0);
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}
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rtcdrv->overflow_rtc = rtcdrv->saved_overflow_rtc;
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/*
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* if current counter is small than previous,
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* it means overflow in sleep
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*/
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tmp = sirfsoc_rtc_readl(rtcdrv, RTC_CN);
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if (tmp <= rtcdrv->saved_counter)
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rtcdrv->overflow_rtc++;
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/*
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*PWRC Value Be Changed When Suspend, Restore Overflow
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* In Memory To Register
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*/
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sirfsoc_rtc_writel(rtcdrv, RTC_SW_VALUE, rtcdrv->overflow_rtc);
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if (device_may_wakeup(dev) && rtcdrv->irq_wake) {
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disable_irq_wake(rtcdrv->irq);
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rtcdrv->irq_wake = 0;
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}
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return 0;
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}
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#endif
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static SIMPLE_DEV_PM_OPS(sirfsoc_rtc_pm_ops,
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sirfsoc_rtc_suspend, sirfsoc_rtc_resume);
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static struct platform_driver sirfsoc_rtc_driver = {
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.driver = {
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.name = "sirfsoc-rtc",
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.pm = &sirfsoc_rtc_pm_ops,
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.of_match_table = sirfsoc_rtc_of_match,
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},
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.probe = sirfsoc_rtc_probe,
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.remove = sirfsoc_rtc_remove,
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};
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module_platform_driver(sirfsoc_rtc_driver);
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MODULE_DESCRIPTION("SiRF SoC rtc driver");
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MODULE_AUTHOR("Xianglong Du <Xianglong.Du@csr.com>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:sirfsoc-rtc");
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