gemini: add rtc-gemini driver

Signed-off-by: Roman Yeryomin <roman@advem.lv>

SVN-Revision: 43884

1 files changed, 220 insertions, 0 deletions

diff --git a/target/linux/gemini/files/drivers/rtc/rtc-gemini.c b/target/linux/gemini/files/drivers/rtc/rtc-gemini.c
new file mode 100644
index 0000000..587d812
--- /dev/null
+++ b/target/linux/gemini/files/drivers/rtc/rtc-gemini.c
@@ -0,0 +1,220 @@
+/*
+ *  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.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Original code for older kernel 2.6.15 are form Stormlinksemi
+ * first update from Janos Laube for > 2.6.29 kernels
+ *
+ * checkpatch fixes and usage off 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>
+
+#include <mach/hardware.h>
+
+#define DRV_NAME		"rtc-gemini"
+
+MODULE_DESCRIPTION("RTC driver for Gemini SoC");
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_AUTHOR("Hans Ulli Kroll <ulli.kroll@googlemail.com>");
+MODULE_LICENSE("GPL");
+
+struct gemini_rtc {
+	struct rtc_device	*dev;
+	void __iomem		*base;
+	int			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
+ *
+ * The register "day" seams to be fixed, and the register "hour"
+ * has his own mind.
+ *
+ * Maybe we can write directly the hour and days since EPOCH
+ * but in this case the RTC will recalucate to some (other) strange values.
+ * If you write time to the registers you will not read the same values.
+ *
+ * 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->base + GEMINI_RTC_SECOND);
+	min    = readl(rtc->base + GEMINI_RTC_MINUTE);
+	hour   = readl(rtc->base + GEMINI_RTC_HOUR);
+	days   = readl(rtc->base + GEMINI_RTC_DAYS);
+	offset = readl(rtc->base + GEMINI_RTC_RECORD);
+
+	time = offset + days * 86400 + hour * 3600 + min * 60 + sec;
+
+	rtc_time_to_tm(time, tm);
+	return 0;
+}
+
+/*
+ * Maybe there is some hidden register to care ?
+ * looks like register GEMINI_RTC_DAY can count
+ * 365 days * 179 years >= 65535 (uint16)
+ */
+
+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->base + GEMINI_RTC_SECOND);
+	min  = readl(rtc->base + GEMINI_RTC_MINUTE);
+	hour = readl(rtc->base + GEMINI_RTC_HOUR);
+	day  = readl(rtc->base + GEMINI_RTC_DAYS);
+
+	offset = time - (day*86400 + hour*3600 + min*60 + sec);
+
+	writel(offset, rtc->base + GEMINI_RTC_RECORD);
+	writel(0x01,   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 = kzalloc(sizeof(*rtc), GFP_KERNEL);
+	if (unlikely(!rtc))
+		return -ENOMEM;
+	platform_set_drvdata(pdev, rtc);
+
+	rtc->irq = platform_get_irq(pdev, 0);
+	if (rtc->irq < 0) {
+		ret = -rtc->irq;
+		goto err_mem;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -ENODEV;
+		goto err_mem;
+	}
+	rtc->base = devm_ioremap(&pdev->dev, res->start,
+				res->end - res->start + 1);
+
+	ret = request_irq(rtc->irq, gemini_rtc_interrupt,
+				IRQF_SHARED, pdev->name, dev);
+	if (unlikely(ret))
+		goto err_mem;
+
+	rtc->dev =	rtc_device_register(pdev->name, dev,
+				&gemini_rtc_ops, THIS_MODULE);
+	if (unlikely(IS_ERR(rtc->dev))) {
+		ret = PTR_ERR(rtc->dev);
+		goto err_irq;
+	}
+	return 0;
+
+err_irq:
+	free_irq(rtc->irq, dev);
+
+err_mem:
+	kfree(rtc);
+	return ret;
+}
+
+static int gemini_rtc_remove(struct platform_device *pdev)
+{
+	struct gemini_rtc *rtc = platform_get_drvdata(pdev);
+	struct device *dev = &pdev->dev;
+
+	free_irq(rtc->irq, dev);
+	rtc_device_unregister(rtc->dev);
+	platform_set_drvdata(pdev, NULL);
+	kfree(rtc);
+
+	return 0;
+}
+
+static struct platform_driver gemini_rtc_driver = {
+	.driver		= {
+		.name	= DRV_NAME,
+		.owner	= THIS_MODULE,
+	},
+	.probe		= gemini_rtc_probe,
+	.remove		= gemini_rtc_remove,
+};
+
+static int __init gemini_rtc_init(void)
+{
+	int	retval;
+
+	retval = platform_driver_register(&gemini_rtc_driver);
+	if (retval == 0)
+		pr_info(DRV_NAME ": registered successfully");
+	return retval;
+}
+
+static void __exit gemini_rtc_exit(void)
+{
+	platform_driver_unregister(&gemini_rtc_driver);
+}
+
+module_init(gemini_rtc_init);
+module_exit(gemini_rtc_exit);