diff options
Diffstat (limited to 'drivers/rtc/rtc-sirfsoc.c')
| -rw-r--r-- | drivers/rtc/rtc-sirfsoc.c | 423 |
1 files changed, 423 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-sirfsoc.c b/drivers/rtc/rtc-sirfsoc.c new file mode 100644 index 00000000000..76e38007ba9 --- /dev/null +++ b/drivers/rtc/rtc-sirfsoc.c @@ -0,0 +1,423 @@ +/* + * 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); + + 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; + } + + /* 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->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"); |