diff options
Diffstat (limited to 'drivers/rtc/rtc-snvs.c')
| -rw-r--r-- | drivers/rtc/rtc-snvs.c | 350 |
1 files changed, 350 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c new file mode 100644 index 00000000000..3c0da333f46 --- /dev/null +++ b/drivers/rtc/rtc-snvs.c @@ -0,0 +1,350 @@ +/* + * Copyright (C) 2011-2012 Freescale Semiconductor, Inc. + * + * The code contained herein is licensed under the GNU General Public + * License. You may obtain a copy of the GNU General Public License + * Version 2 or later at the following locations: + * + * http://www.opensource.org/licenses/gpl-license.html + * http://www.gnu.org/copyleft/gpl.html + */ + +#include <linux/init.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/rtc.h> + +/* These register offsets are relative to LP (Low Power) range */ +#define SNVS_LPCR 0x04 +#define SNVS_LPSR 0x18 +#define SNVS_LPSRTCMR 0x1c +#define SNVS_LPSRTCLR 0x20 +#define SNVS_LPTAR 0x24 +#define SNVS_LPPGDR 0x30 + +#define SNVS_LPCR_SRTC_ENV (1 << 0) +#define SNVS_LPCR_LPTA_EN (1 << 1) +#define SNVS_LPCR_LPWUI_EN (1 << 3) +#define SNVS_LPSR_LPTA (1 << 0) + +#define SNVS_LPPGDR_INIT 0x41736166 +#define CNTR_TO_SECS_SH 15 + +struct snvs_rtc_data { + struct rtc_device *rtc; + void __iomem *ioaddr; + int irq; + spinlock_t lock; +}; + +static u32 rtc_read_lp_counter(void __iomem *ioaddr) +{ + u64 read1, read2; + + do { + read1 = readl(ioaddr + SNVS_LPSRTCMR); + read1 <<= 32; + read1 |= readl(ioaddr + SNVS_LPSRTCLR); + + read2 = readl(ioaddr + SNVS_LPSRTCMR); + read2 <<= 32; + read2 |= readl(ioaddr + SNVS_LPSRTCLR); + } while (read1 != read2); + + /* Convert 47-bit counter to 32-bit raw second count */ + return (u32) (read1 >> CNTR_TO_SECS_SH); +} + +static void rtc_write_sync_lp(void __iomem *ioaddr) +{ + u32 count1, count2, count3; + int i; + + /* Wait for 3 CKIL cycles */ + for (i = 0; i < 3; i++) { + do { + count1 = readl(ioaddr + SNVS_LPSRTCLR); + count2 = readl(ioaddr + SNVS_LPSRTCLR); + } while (count1 != count2); + + /* Now wait until counter value changes */ + do { + do { + count2 = readl(ioaddr + SNVS_LPSRTCLR); + count3 = readl(ioaddr + SNVS_LPSRTCLR); + } while (count2 != count3); + } while (count3 == count1); + } +} + +static int snvs_rtc_enable(struct snvs_rtc_data *data, bool enable) +{ + unsigned long flags; + int timeout = 1000; + u32 lpcr; + + spin_lock_irqsave(&data->lock, flags); + + lpcr = readl(data->ioaddr + SNVS_LPCR); + if (enable) + lpcr |= SNVS_LPCR_SRTC_ENV; + else + lpcr &= ~SNVS_LPCR_SRTC_ENV; + writel(lpcr, data->ioaddr + SNVS_LPCR); + + spin_unlock_irqrestore(&data->lock, flags); + + while (--timeout) { + lpcr = readl(data->ioaddr + SNVS_LPCR); + + if (enable) { + if (lpcr & SNVS_LPCR_SRTC_ENV) + break; + } else { + if (!(lpcr & SNVS_LPCR_SRTC_ENV)) + break; + } + } + + if (!timeout) + return -ETIMEDOUT; + + return 0; +} + +static int snvs_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct snvs_rtc_data *data = dev_get_drvdata(dev); + unsigned long time = rtc_read_lp_counter(data->ioaddr); + + rtc_time_to_tm(time, tm); + + return 0; +} + +static int snvs_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct snvs_rtc_data *data = dev_get_drvdata(dev); + unsigned long time; + + rtc_tm_to_time(tm, &time); + + /* Disable RTC first */ + snvs_rtc_enable(data, false); + + /* Write 32-bit time to 47-bit timer, leaving 15 LSBs blank */ + writel(time << CNTR_TO_SECS_SH, data->ioaddr + SNVS_LPSRTCLR); + writel(time >> (32 - CNTR_TO_SECS_SH), data->ioaddr + SNVS_LPSRTCMR); + + /* Enable RTC again */ + snvs_rtc_enable(data, true); + + return 0; +} + +static int snvs_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct snvs_rtc_data *data = dev_get_drvdata(dev); + u32 lptar, lpsr; + + lptar = readl(data->ioaddr + SNVS_LPTAR); + rtc_time_to_tm(lptar, &alrm->time); + + lpsr = readl(data->ioaddr + SNVS_LPSR); + alrm->pending = (lpsr & SNVS_LPSR_LPTA) ? 1 : 0; + + return 0; +} + +static int snvs_rtc_alarm_irq_enable(struct device *dev, unsigned int enable) +{ + struct snvs_rtc_data *data = dev_get_drvdata(dev); + u32 lpcr; + unsigned long flags; + + spin_lock_irqsave(&data->lock, flags); + + lpcr = readl(data->ioaddr + SNVS_LPCR); + if (enable) + lpcr |= (SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN); + else + lpcr &= ~(SNVS_LPCR_LPTA_EN | SNVS_LPCR_LPWUI_EN); + writel(lpcr, data->ioaddr + SNVS_LPCR); + + spin_unlock_irqrestore(&data->lock, flags); + + rtc_write_sync_lp(data->ioaddr); + + return 0; +} + +static int snvs_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct snvs_rtc_data *data = dev_get_drvdata(dev); + struct rtc_time *alrm_tm = &alrm->time; + unsigned long time; + unsigned long flags; + u32 lpcr; + + rtc_tm_to_time(alrm_tm, &time); + + spin_lock_irqsave(&data->lock, flags); + + /* Have to clear LPTA_EN before programming new alarm time in LPTAR */ + lpcr = readl(data->ioaddr + SNVS_LPCR); + lpcr &= ~SNVS_LPCR_LPTA_EN; + writel(lpcr, data->ioaddr + SNVS_LPCR); + + spin_unlock_irqrestore(&data->lock, flags); + + writel(time, data->ioaddr + SNVS_LPTAR); + + /* Clear alarm interrupt status bit */ + writel(SNVS_LPSR_LPTA, data->ioaddr + SNVS_LPSR); + + return snvs_rtc_alarm_irq_enable(dev, alrm->enabled); +} + +static const struct rtc_class_ops snvs_rtc_ops = { + .read_time = snvs_rtc_read_time, + .set_time = snvs_rtc_set_time, + .read_alarm = snvs_rtc_read_alarm, + .set_alarm = snvs_rtc_set_alarm, + .alarm_irq_enable = snvs_rtc_alarm_irq_enable, +}; + +static irqreturn_t snvs_rtc_irq_handler(int irq, void *dev_id) +{ + struct device *dev = dev_id; + struct snvs_rtc_data *data = dev_get_drvdata(dev); + u32 lpsr; + u32 events = 0; + + lpsr = readl(data->ioaddr + SNVS_LPSR); + + if (lpsr & SNVS_LPSR_LPTA) { + events |= (RTC_AF | RTC_IRQF); + + /* RTC alarm should be one-shot */ + snvs_rtc_alarm_irq_enable(dev, 0); + + rtc_update_irq(data->rtc, 1, events); + } + + /* clear interrupt status */ + writel(lpsr, data->ioaddr + SNVS_LPSR); + + return events ? IRQ_HANDLED : IRQ_NONE; +} + +static int __devinit snvs_rtc_probe(struct platform_device *pdev) +{ + struct snvs_rtc_data *data; + struct resource *res; + int ret; + + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + data->ioaddr = devm_request_and_ioremap(&pdev->dev, res); + if (!data->ioaddr) + return -EADDRNOTAVAIL; + + data->irq = platform_get_irq(pdev, 0); + if (data->irq < 0) + return data->irq; + + platform_set_drvdata(pdev, data); + + spin_lock_init(&data->lock); + + /* Initialize glitch detect */ + writel(SNVS_LPPGDR_INIT, data->ioaddr + SNVS_LPPGDR); + + /* Clear interrupt status */ + writel(0xffffffff, data->ioaddr + SNVS_LPSR); + + /* Enable RTC */ + snvs_rtc_enable(data, true); + + device_init_wakeup(&pdev->dev, true); + + ret = devm_request_irq(&pdev->dev, data->irq, snvs_rtc_irq_handler, + IRQF_SHARED, "rtc alarm", &pdev->dev); + if (ret) { + dev_err(&pdev->dev, "failed to request irq %d: %d\n", + data->irq, ret); + return ret; + } + + data->rtc = rtc_device_register(pdev->name, &pdev->dev, + &snvs_rtc_ops, THIS_MODULE); + if (IS_ERR(data->rtc)) { + ret = PTR_ERR(data->rtc); + dev_err(&pdev->dev, "failed to register rtc: %d\n", ret); + return ret; + } + + return 0; +} + +static int __devexit snvs_rtc_remove(struct platform_device *pdev) +{ + struct snvs_rtc_data *data = platform_get_drvdata(pdev); + + rtc_device_unregister(data->rtc); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int snvs_rtc_suspend(struct device *dev) +{ + struct snvs_rtc_data *data = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + enable_irq_wake(data->irq); + + return 0; +} + +static int snvs_rtc_resume(struct device *dev) +{ + struct snvs_rtc_data *data = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + disable_irq_wake(data->irq); + + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(snvs_rtc_pm_ops, snvs_rtc_suspend, snvs_rtc_resume); + +static const struct of_device_id __devinitconst snvs_dt_ids[] = { + { .compatible = "fsl,sec-v4.0-mon-rtc-lp", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, snvs_dt_ids); + +static struct platform_driver snvs_rtc_driver = { + .driver = { + .name = "snvs_rtc", + .owner = THIS_MODULE, + .pm = &snvs_rtc_pm_ops, + .of_match_table = snvs_dt_ids, + }, + .probe = snvs_rtc_probe, + .remove = __devexit_p(snvs_rtc_remove), +}; +module_platform_driver(snvs_rtc_driver); + +MODULE_AUTHOR("Freescale Semiconductor, Inc."); +MODULE_DESCRIPTION("Freescale SNVS RTC Driver"); +MODULE_LICENSE("GPL"); |