1 files changed, 150 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-aspeed.c b/drivers/rtc/rtc-aspeed.c
new file mode 100644
index 000000000000..bc5c30ddddfd
--- /dev/null
+++ b/drivers/rtc/rtc-aspeed.c
@@ -0,0 +1,150 @@
+/*
+ * RTC driver for the Aspeed 24xx SoCs
+ *
+ * Copyright 2015 IBM Corp.
+ *
+ * Joel Stanley <joel@jms.id.au >
+ *
+ * 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.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/io.h>
+
+struct aspeed_rtc {
+	struct rtc_device	*rtc_dev;
+	void __iomem		*base;
+	spinlock_t		lock;
+};
+
+#define RTC_TIME	0x00
+#define RTC_YEAR	0x04
+#define RTC_CTRL	0x10
+
+#define RTC_UNLOCK	0x02
+#define RTC_ENABLE	0x01
+
+static int aspeed_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct aspeed_rtc *rtc = dev_get_drvdata(dev);
+	unsigned int cent, year, mon, day, hour, min, sec;
+	u32 reg1, reg2;
+
+	do {
+		reg2 = readl(rtc->base + RTC_YEAR);
+		reg1 = readl(rtc->base + RTC_TIME);
+	} while (reg2 != readl(rtc->base + RTC_YEAR));
+
+	day  = (reg1 >> 24) & 0x1f;
+	hour = (reg1 >> 16) & 0x1f;
+	min  = (reg1 >>  8) & 0x3f;
+	sec  = (reg1 >>  0) & 0x3f;
+	cent = (reg2 >> 16) & 0x1f;
+	year = (reg2 >>  8) & 0x7f;
+	/* Month is 1-12 in hardware, and 0-11 in struct rtc_time, however we
+	 * are using mktime64 which is 1-12, so no adjustment is necessary */
+	mon  = (reg2 >>  0) & 0x0f;
+
+	rtc_time64_to_tm(mktime64(cent*100 + year, mon, day, hour, min, sec),
+			 tm);
+
+	return 0;
+}
+
+static int aspeed_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct aspeed_rtc *rtc = dev_get_drvdata(dev);
+	unsigned long flags;
+	u32 reg1, reg2, ctrl;
+	int year, cent;
+
+	/* tm_year counts from 1900 */
+	cent = (tm->tm_year + 1900) / 100;
+	year = tm->tm_year % 100;
+
+	reg1 = (tm->tm_mday << 24) | (tm->tm_hour << 16) | (tm->tm_min << 8) |
+		tm->tm_sec;
+
+	/* Month in struct rtc_time is 0-11, but the hardware is 1-12 */
+	reg2 = ((cent & 0x1f) << 16) | ((year & 0x7f) << 8) |
+		((tm->tm_mon & 0xf) + 1);
+
+	/* TODO: Do we need to lock? */
+	spin_lock_irqsave(&rtc->lock, flags);
+
+	ctrl = readl(rtc->base + RTC_CTRL);
+	writel(ctrl | RTC_UNLOCK, rtc->base + RTC_CTRL);
+
+	writel(reg1, rtc->base + RTC_TIME);
+	writel(reg2, rtc->base + RTC_YEAR);
+
+	writel(ctrl, rtc->base + RTC_CTRL);
+
+	spin_unlock_irqrestore(&rtc->lock, flags);
+
+	return 0;
+}
+
+static struct rtc_class_ops aspeed_rtc_ops = {
+	.read_time = aspeed_rtc_read_time,
+	.set_time = aspeed_rtc_set_time,
+};
+
+static int aspeed_rtc_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct aspeed_rtc *rtc;
+
+	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	rtc->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(rtc->base))
+		return PTR_ERR(rtc->base);
+
+	platform_set_drvdata(pdev, rtc);
+
+	rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name,
+						&aspeed_rtc_ops, THIS_MODULE);
+
+	if (IS_ERR(rtc->rtc_dev)) {
+		dev_err(&pdev->dev, "failed to register\n");
+		return PTR_ERR(rtc->rtc_dev);
+	}
+
+	spin_lock_init(&rtc->lock);
+
+	/* Enable RTC and clear the unlock bit */
+	writel(RTC_ENABLE, rtc->base + RTC_CTRL);
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id aspeed_rtc_of_match_table[] = {
+	{ .compatible = "aspeed,rtc", },
+	{}
+};
+#endif
+
+static struct platform_driver aspeed_rtc_driver = {
+	.driver = {
+		.name = "aspeed-rtc",
+		.of_match_table = of_match_ptr(aspeed_rtc_of_match_table),
+	},
+};
+
+module_platform_driver_probe(aspeed_rtc_driver, aspeed_rtc_probe);
+
+MODULE_DESCRIPTION("Aspeed AST24xx RTC driver");
+MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
+MODULE_LICENSE("GPL");