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