/* drivers/rtc/rtc-goldfish.c * * Copyright (C) 2007 Google, Inc. * Copyright (C) 2017 Imagination Technologies Ltd. * * This software is licensed under the terms of the GNU General Public * License version 2, as published by the Free Software Foundation, and * may be copied, distributed, and modified under those terms. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * */ #include <linux/module.h> #include <linux/platform_device.h> #include <linux/rtc.h> #include <linux/io.h> #define TIMER_TIME_LOW 0x00 /* get low bits of current time */ /* and update TIMER_TIME_HIGH */ #define TIMER_TIME_HIGH 0x04 /* get high bits of time at last */ /* TIMER_TIME_LOW read */ #define TIMER_ALARM_LOW 0x08 /* set low bits of alarm and */ /* activate it */ #define TIMER_ALARM_HIGH 0x0c /* set high bits of next alarm */ #define TIMER_IRQ_ENABLED 0x10 #define TIMER_CLEAR_ALARM 0x14 #define TIMER_ALARM_STATUS 0x18 #define TIMER_CLEAR_INTERRUPT 0x1c struct goldfish_rtc { void __iomem *base; int irq; struct rtc_device *rtc; }; static int goldfish_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) { u64 rtc_alarm; u64 rtc_alarm_low; u64 rtc_alarm_high; void __iomem *base; struct goldfish_rtc *rtcdrv; rtcdrv = dev_get_drvdata(dev); base = rtcdrv->base; rtc_alarm_low = readl(base + TIMER_ALARM_LOW); rtc_alarm_high = readl(base + TIMER_ALARM_HIGH); rtc_alarm = (rtc_alarm_high << 32) | rtc_alarm_low; do_div(rtc_alarm, NSEC_PER_SEC); memset(alrm, 0, sizeof(struct rtc_wkalrm)); rtc_time_to_tm(rtc_alarm, &alrm->time); if (readl(base + TIMER_ALARM_STATUS)) alrm->enabled = 1; else alrm->enabled = 0; return 0; } static int goldfish_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct goldfish_rtc *rtcdrv; unsigned long rtc_alarm; u64 rtc_alarm64; u64 rtc_status_reg; void __iomem *base; int ret = 0; rtcdrv = dev_get_drvdata(dev); base = rtcdrv->base; if (alrm->enabled) { ret = rtc_tm_to_time(&alrm->time, &rtc_alarm); if (ret != 0) return ret; rtc_alarm64 = rtc_alarm * NSEC_PER_SEC; writel((rtc_alarm64 >> 32), base + TIMER_ALARM_HIGH); writel(rtc_alarm64, base + TIMER_ALARM_LOW); } else { /* * if this function was called with enabled=0 * then it could mean that the application is * trying to cancel an ongoing alarm */ rtc_status_reg = readl(base + TIMER_ALARM_STATUS); if (rtc_status_reg) writel(1, base + TIMER_CLEAR_ALARM); } return ret; } static int goldfish_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) { void __iomem *base; struct goldfish_rtc *rtcdrv; rtcdrv = dev_get_drvdata(dev); base = rtcdrv->base; if (enabled) writel(1, base + TIMER_IRQ_ENABLED); else writel(0, base + TIMER_IRQ_ENABLED); return 0; } static irqreturn_t goldfish_rtc_interrupt(int irq, void *dev_id) { struct goldfish_rtc *rtcdrv = dev_id; void __iomem *base = rtcdrv->base; writel(1, base + TIMER_CLEAR_INTERRUPT); rtc_update_irq(rtcdrv->rtc, 1, RTC_IRQF | RTC_AF); return IRQ_HANDLED; } static int goldfish_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct goldfish_rtc *rtcdrv; void __iomem *base; u64 time_high; u64 time_low; u64 time; rtcdrv = dev_get_drvdata(dev); base = rtcdrv->base; time_low = readl(base + TIMER_TIME_LOW); time_high = readl(base + TIMER_TIME_HIGH); time = (time_high << 32) | time_low; do_div(time, NSEC_PER_SEC); rtc_time_to_tm(time, tm); return 0; } static int goldfish_rtc_set_time(struct device *dev, struct rtc_time *tm) { struct goldfish_rtc *rtcdrv; void __iomem *base; unsigned long now; u64 now64; int ret; rtcdrv = dev_get_drvdata(dev); base = rtcdrv->base; ret = rtc_tm_to_time(tm, &now); if (ret == 0) { now64 = now * NSEC_PER_SEC; writel((now64 >> 32), base + TIMER_TIME_HIGH); writel(now64, base + TIMER_TIME_LOW); } return ret; } static const struct rtc_class_ops goldfish_rtc_ops = { .read_time = goldfish_rtc_read_time, .set_time = goldfish_rtc_set_time, .read_alarm = goldfish_rtc_read_alarm, .set_alarm = goldfish_rtc_set_alarm, .alarm_irq_enable = goldfish_rtc_alarm_irq_enable }; static int goldfish_rtc_probe(struct platform_device *pdev) { struct goldfish_rtc *rtcdrv; struct resource *r; int err; rtcdrv = devm_kzalloc(&pdev->dev, sizeof(*rtcdrv), GFP_KERNEL); if (!rtcdrv) return -ENOMEM; platform_set_drvdata(pdev, rtcdrv); r = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!r) return -ENODEV; rtcdrv->base = devm_ioremap_resource(&pdev->dev, r); if (IS_ERR(rtcdrv->base)) return -ENODEV; rtcdrv->irq = platform_get_irq(pdev, 0); if (rtcdrv->irq < 0) return -ENODEV; rtcdrv->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &goldfish_rtc_ops, THIS_MODULE); if (IS_ERR(rtcdrv->rtc)) return PTR_ERR(rtcdrv->rtc); err = devm_request_irq(&pdev->dev, rtcdrv->irq, goldfish_rtc_interrupt, 0, pdev->name, rtcdrv); if (err) return err; return 0; } static const struct of_device_id goldfish_rtc_of_match[] = { { .compatible = "google,goldfish-rtc", }, {}, }; MODULE_DEVICE_TABLE(of, goldfish_rtc_of_match); static struct platform_driver goldfish_rtc = { .probe = goldfish_rtc_probe, .driver = { .name = "goldfish_rtc", .of_match_table = goldfish_rtc_of_match, } }; module_platform_driver(goldfish_rtc); MODULE_LICENSE("GPL v2");