diff options
Diffstat (limited to 'drivers/rtc/rtc-goldfish.c')
| -rw-r--r-- | drivers/rtc/rtc-goldfish.c | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-goldfish.c b/drivers/rtc/rtc-goldfish.c new file mode 100644 index 000000000..30cbe22c5 --- /dev/null +++ b/drivers/rtc/rtc-goldfish.c @@ -0,0 +1,240 @@ +/* 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); + writel(1, base + TIMER_IRQ_ENABLED); + } 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"); |