diff options
Diffstat (limited to 'kernel/drivers/rtc/rtc-gemini.c')
| -rw-r--r-- | kernel/drivers/rtc/rtc-gemini.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/kernel/drivers/rtc/rtc-gemini.c b/kernel/drivers/rtc/rtc-gemini.c new file mode 100644 index 000000000..e84184647 --- /dev/null +++ b/kernel/drivers/rtc/rtc-gemini.c @@ -0,0 +1,172 @@ +/* + * Gemini OnChip RTC + * + * Copyright (C) 2009 Janos Laube <janos.dev@gmail.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * 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. + * + * Original code for older kernel 2.6.15 are from Stormlinksemi + * first update from Janos Laube for > 2.6.29 kernels + * + * checkpatch fixes and usage of rtc-lib code + * Hans Ulli Kroll <ulli.kroll@googlemail.com> + */ + +#include <linux/rtc.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <linux/platform_device.h> +#include <linux/kernel.h> +#include <linux/module.h> + +#define DRV_NAME "rtc-gemini" +#define DRV_VERSION "0.2" + +MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>"); +MODULE_DESCRIPTION("RTC driver for Gemini SoC"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" DRV_NAME); + +struct gemini_rtc { + struct rtc_device *rtc_dev; + void __iomem *rtc_base; + int rtc_irq; +}; + +enum gemini_rtc_offsets { + GEMINI_RTC_SECOND = 0x00, + GEMINI_RTC_MINUTE = 0x04, + GEMINI_RTC_HOUR = 0x08, + GEMINI_RTC_DAYS = 0x0C, + GEMINI_RTC_ALARM_SECOND = 0x10, + GEMINI_RTC_ALARM_MINUTE = 0x14, + GEMINI_RTC_ALARM_HOUR = 0x18, + GEMINI_RTC_RECORD = 0x1C, + GEMINI_RTC_CR = 0x20 +}; + +static irqreturn_t gemini_rtc_interrupt(int irq, void *dev) +{ + return IRQ_HANDLED; +} + +/* + * Looks like the RTC in the Gemini SoC is (totaly) broken + * We can't read/write directly the time from RTC registers. + * We must do some "offset" calculation to get the real time + * + * This FIX works pretty fine and Stormlinksemi aka Cortina-Networks does + * the same thing, without the rtc-lib.c calls. + */ + +static int gemini_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct gemini_rtc *rtc = dev_get_drvdata(dev); + + unsigned int days, hour, min, sec; + unsigned long offset, time; + + sec = readl(rtc->rtc_base + GEMINI_RTC_SECOND); + min = readl(rtc->rtc_base + GEMINI_RTC_MINUTE); + hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR); + days = readl(rtc->rtc_base + GEMINI_RTC_DAYS); + offset = readl(rtc->rtc_base + GEMINI_RTC_RECORD); + + time = offset + days * 86400 + hour * 3600 + min * 60 + sec; + + rtc_time_to_tm(time, tm); + + return 0; +} + +static int gemini_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct gemini_rtc *rtc = dev_get_drvdata(dev); + unsigned int sec, min, hour, day; + unsigned long offset, time; + + if (tm->tm_year >= 2148) /* EPOCH Year + 179 */ + return -EINVAL; + + rtc_tm_to_time(tm, &time); + + sec = readl(rtc->rtc_base + GEMINI_RTC_SECOND); + min = readl(rtc->rtc_base + GEMINI_RTC_MINUTE); + hour = readl(rtc->rtc_base + GEMINI_RTC_HOUR); + day = readl(rtc->rtc_base + GEMINI_RTC_DAYS); + + offset = time - (day * 86400 + hour * 3600 + min * 60 + sec); + + writel(offset, rtc->rtc_base + GEMINI_RTC_RECORD); + writel(0x01, rtc->rtc_base + GEMINI_RTC_CR); + + return 0; +} + +static struct rtc_class_ops gemini_rtc_ops = { + .read_time = gemini_rtc_read_time, + .set_time = gemini_rtc_set_time, +}; + +static int gemini_rtc_probe(struct platform_device *pdev) +{ + struct gemini_rtc *rtc; + struct device *dev = &pdev->dev; + struct resource *res; + int ret; + + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); + if (unlikely(!rtc)) + return -ENOMEM; + platform_set_drvdata(pdev, rtc); + + res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (!res) + return -ENODEV; + + rtc->rtc_irq = res->start; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENODEV; + + rtc->rtc_base = devm_ioremap(dev, res->start, + resource_size(res)); + + ret = devm_request_irq(dev, rtc->rtc_irq, gemini_rtc_interrupt, + IRQF_SHARED, pdev->name, dev); + if (unlikely(ret)) + return ret; + + rtc->rtc_dev = rtc_device_register(pdev->name, dev, + &gemini_rtc_ops, THIS_MODULE); + return PTR_ERR_OR_ZERO(rtc->rtc_dev); +} + +static int gemini_rtc_remove(struct platform_device *pdev) +{ + struct gemini_rtc *rtc = platform_get_drvdata(pdev); + + rtc_device_unregister(rtc->rtc_dev); + platform_set_drvdata(pdev, NULL); + + return 0; +} + +static struct platform_driver gemini_rtc_driver = { + .driver = { + .name = DRV_NAME, + }, + .probe = gemini_rtc_probe, + .remove = gemini_rtc_remove, +}; + +module_platform_driver_probe(gemini_rtc_driver, gemini_rtc_probe); |