[PATCH 1/1] Driver for the Atmel on-chip RTC on AT32AP700x devices.
From: Hans-Christian Egtvedt
Date: Fri Jun 08 2007 - 07:49:54 EST
Tested on the AT32AP7000/ATSTK1000. Driver does only suport time, wake up and a
very simple alarm, because of hardware limitations.
Hardware documentation can be found in the AT32AP7000 data sheet, which can be
downloaded from
http://www.atmel.com/dyn/products/datasheets.asp?family_id=682
Signed-off-by: Hans-Christian Egtvedt <hcegtvedt@xxxxxxxxx>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>
---
drivers/rtc/Kconfig | 7 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-at32ap700x.c | 337 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 345 insertions(+), 0 deletions(-)
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 95826b9..ee96d77 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -313,6 +313,13 @@ config RTC_DRV_PL031
To compile this driver as a module, choose M here: the
module will be called rtc-pl031.
+config RTC_DRV_AT32AP700X
+ tristate "AT32AP700X series RTC"
+ depends on RTC_CLASS && PLATFORM_AT32AP
+ help
+ Driver for the internal RTC (Realtime Clock) on Atmel AVR32
+ AT32AP700x family processors.
+
config RTC_DRV_AT91RM9200
tristate "AT91RM9200"
depends on RTC_CLASS && ARCH_AT91RM9200
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 92bfe1b..d36d987 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_RTC_DRV_CMOS) += rtc-cmos.o
obj-$(CONFIG_RTC_DRV_X1205) += rtc-x1205.o
obj-$(CONFIG_RTC_DRV_ISL1208) += rtc-isl1208.o
obj-$(CONFIG_RTC_DRV_TEST) += rtc-test.o
+obj-$(CONFIG_RTC_DRV_AT32AP700X) += rtc-at32ap700x.o
obj-$(CONFIG_RTC_DRV_DS1307) += rtc-ds1307.o
obj-$(CONFIG_RTC_DRV_DS1672) += rtc-ds1672.o
obj-$(CONFIG_RTC_DRV_DS1742) += rtc-ds1742.o
diff --git a/drivers/rtc/rtc-at32ap700x.c b/drivers/rtc/rtc-at32ap700x.c
new file mode 100644
index 0000000..61307ed
--- /dev/null
+++ b/drivers/rtc/rtc-at32ap700x.c
@@ -0,0 +1,337 @@
+/*
+ * An RTC driver for the AVR32 AT32AP700x processor series.
+ *
+ * Copyright (C) 2007 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+
+#include <asm/io.h>
+
+/*
+ * This is a bare-bones RTC. It runs during most system sleep states, but has
+ * no battery backup and gets reset during system restart. It must be
+ * initialized from an external clock (network, I2C, etc) before it can be of
+ * much use.
+ *
+ * The alarm functionality is limited by the hardware, not supporting
+ * periodic interrupts.
+ */
+
+#define RTC_CTRL 0x00
+#define RTC_CTRL_EN 0
+#define RTC_CTRL_PCLR 1
+#define RTC_CTRL_TOPEN 2
+#define RTC_CTRL_PSEL 8
+
+#define RTC_VAL 0x04
+
+#define RTC_TOP 0x08
+
+#define RTC_IER 0x10
+#define RTC_IER_TOPI 0
+
+#define RTC_IDR 0x14
+#define RTC_IDR_TOPI 0
+
+#define RTC_IMR 0x18
+#define RTC_IMR_TOPI 0
+
+#define RTC_ISR 0x1c
+#define RTC_ISR_TOPI 0
+
+#define RTC_ICR 0x20
+#define RTC_ICR_TOPI 0
+
+#define RTC_BIT(name) (1 << RTC_##name)
+#define RTC_BF(name,value) ((value) << RTC_##name)
+
+#define rtc_readl(dev,reg) \
+ __raw_readl((dev)->regs + RTC_##reg)
+#define rtc_writel(dev,reg,value) \
+ __raw_writel((value), (dev)->regs + RTC_##reg)
+
+struct rtc_at32ap700x {
+ struct rtc_device *rtc;
+ void __iomem *regs;
+ unsigned long alarm_time;
+ unsigned long irq;
+ spinlock_t lock;
+};
+
+static int at32_rtc_readtime(struct device *dev, struct rtc_time *tm)
+{
+ struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
+ unsigned long now;
+
+ now = rtc_readl(rtc, VAL);
+ rtc_time_to_tm(now, tm);
+
+ return 0;
+}
+
+static int at32_rtc_settime(struct device *dev, struct rtc_time *tm)
+{
+ struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
+ unsigned long now;
+ int ret;
+
+ ret = rtc_tm_to_time(tm, &now);
+ if (ret == 0)
+ rtc_writel(rtc, VAL, now);
+
+ return ret;
+}
+
+static int at32_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
+
+ rtc_time_to_tm(rtc->alarm_time, &alrm->time);
+ alrm->pending = rtc_readl(rtc, IMR) & RTC_BIT(IMR_TOPI) ? 1 : 0;
+
+ return 0;
+}
+
+static int at32_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
+ unsigned long rtc_unix_time;
+ unsigned long alarm_unix_time;
+ int ret;
+
+ rtc_unix_time = rtc_readl(rtc, VAL);
+
+ /* RTC does only support one alarm time, not periodic */
+ if (alrm->time.tm_mday <= 0) {
+ struct rtc_time tm;
+ unsigned long then;
+
+ rtc_time_to_tm(rtc_unix_time, &tm);
+
+ alrm->time.tm_mday = tm.tm_mday;
+ alrm->time.tm_mon = tm.tm_mon;
+ alrm->time.tm_year = tm.tm_year;
+
+ rtc_tm_to_time(&alrm->time, &then);
+
+ /* check if the alarm wraps into tomorrow */
+ if (then < rtc_unix_time) {
+ rtc_time_to_tm(rtc_unix_time + 24 * 60 * 60, &tm);
+ alrm->time.tm_mday = tm.tm_mday;
+ alrm->time.tm_mon = tm.tm_mon;
+ alrm->time.tm_year = tm.tm_year;
+ }
+ }
+
+ ret = rtc_tm_to_time(&alrm->time, &alarm_unix_time);
+ if (ret)
+ return ret;
+
+ if (alarm_unix_time < rtc_unix_time)
+ return -EINVAL;
+
+ spin_lock_irq(&rtc->lock);
+ rtc->alarm_time = alarm_unix_time;
+ rtc_writel(rtc, TOP, rtc->alarm_time);
+ if (alrm->pending)
+ rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
+ | RTC_BIT(CTRL_TOPEN));
+ else
+ rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
+ & ~RTC_BIT(CTRL_TOPEN));
+ spin_unlock_irq(&rtc->lock);
+
+ return ret;
+}
+
+static int at32_rtc_ioctl(struct device *dev, unsigned int cmd,
+ unsigned long arg)
+{
+ struct rtc_at32ap700x *rtc = dev_get_drvdata(dev);
+ int ret = 0;
+
+ spin_lock_irq(&rtc->lock);
+
+ switch (cmd) {
+ case RTC_AIE_ON:
+ if (rtc_readl(rtc, VAL) > rtc->alarm_time) {
+ ret = -EINVAL;
+ break;
+ }
+ rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
+ | RTC_BIT(CTRL_TOPEN));
+ rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
+ rtc_writel(rtc, IER, RTC_BIT(IER_TOPI));
+ break;
+ case RTC_AIE_OFF:
+ rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
+ & ~RTC_BIT(CTRL_TOPEN));
+ rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
+ rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
+ break;
+ default:
+ ret = -ENOIOCTLCMD;
+ break;
+ }
+
+ spin_unlock_irq(&rtc->lock);
+
+ return ret;
+}
+
+static irqreturn_t at32_rtc_interrupt(int irq, void *dev_id)
+{
+ struct rtc_at32ap700x *rtc = (struct rtc_at32ap700x *)dev_id;
+ unsigned long isr = rtc_readl(rtc, ISR);
+ unsigned long events = 0;
+ int ret = IRQ_NONE;
+
+ spin_lock(&rtc->lock);
+
+ if (isr & RTC_BIT(ISR_TOPI)) {
+ rtc_writel(rtc, ICR, RTC_BIT(ICR_TOPI));
+ rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
+ rtc_writel(rtc, CTRL, rtc_readl(rtc, CTRL)
+ & ~RTC_BIT(CTRL_TOPEN));
+ rtc_writel(rtc, VAL, rtc->alarm_time);
+ events = RTC_AF | RTC_IRQF;
+ rtc_update_irq(&rtc->rtc->class_dev, 1, events);
+ ret = IRQ_HANDLED;
+ }
+
+ spin_unlock(&rtc->lock);
+
+ return ret;
+}
+
+static struct rtc_class_ops at32_rtc_ops = {
+ .ioctl = at32_rtc_ioctl,
+ .read_time = at32_rtc_readtime,
+ .set_time = at32_rtc_settime,
+ .read_alarm = at32_rtc_readalarm,
+ .set_alarm = at32_rtc_setalarm,
+};
+
+static int __init at32_rtc_probe(struct platform_device *pdev)
+{
+ struct resource *regs;
+ struct rtc_at32ap700x *rtc;
+ int irq = -1;
+ int ret;
+
+ rtc = kzalloc(sizeof(struct rtc_at32ap700x), GFP_KERNEL);
+ if (!rtc) {
+ dev_dbg(&pdev->dev, "out of memory\n");
+ return -ENOMEM;
+ }
+
+ regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!regs) {
+ dev_dbg(&pdev->dev, "no mmio resource defined\n");
+ ret = -ENXIO;
+ goto out;
+ }
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0) {
+ dev_dbg(&pdev->dev, "could not get irq\n");
+ ret = -ENXIO;
+ goto out;
+ }
+
+ ret = request_irq(irq, at32_rtc_interrupt, IRQF_SHARED, "rtc", rtc);
+ if (ret) {
+ dev_dbg(&pdev->dev, "could not request irq %d\n", irq);
+ goto out;
+ }
+
+ rtc->irq = irq;
+ rtc->regs = ioremap(regs->start, regs->end - regs->start + 1);
+ if (!rtc->regs) {
+ ret = -ENOMEM;
+ dev_dbg(&pdev->dev, "could not map I/O memory\n");
+ goto out_free_irq;
+ }
+ spin_lock_init(&rtc->lock);
+
+ /*
+ * Maybe init RTC: count from zero at 1 Hz, disable wrap irq.
+ *
+ * Do not reset VAL register, as it can hold an old time
+ * from last JTAG reset.
+ */
+ if (!(rtc_readl(rtc, CTRL) & RTC_BIT(CTRL_EN))) {
+ rtc_writel(rtc, CTRL, RTC_BIT(CTRL_PCLR));
+ rtc_writel(rtc, IDR, RTC_BIT(IDR_TOPI));
+ rtc_writel(rtc, CTRL, RTC_BF(CTRL_PSEL, 0xe)
+ | RTC_BIT(CTRL_EN));
+ }
+
+ rtc->rtc = rtc_device_register(pdev->name, &pdev->dev,
+ &at32_rtc_ops, THIS_MODULE);
+ if (IS_ERR(rtc->rtc)) {
+ dev_dbg(&pdev->dev, "could not register rtc device\n");
+ ret = PTR_ERR(rtc->rtc);
+ goto out_iounmap;
+ }
+
+ platform_set_drvdata(pdev, rtc);
+
+ dev_info(&pdev->dev, "Atmel RTC for AT32AP700x at %08lx irq %ld\n",
+ (unsigned long)rtc->regs, rtc->irq);
+
+ return 0;
+
+out_iounmap:
+ iounmap(rtc->regs);
+out_free_irq:
+ free_irq(irq, rtc);
+out:
+ kfree(rtc);
+ return ret;
+}
+
+static int __exit at32_rtc_remove(struct platform_device *pdev)
+{
+ struct rtc_at32ap700x *rtc = platform_get_drvdata(pdev);
+
+ free_irq(rtc->irq, rtc);
+ iounmap(rtc->regs);
+ rtc_device_unregister(rtc->rtc);
+ kfree(rtc);
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+static struct platform_driver at32_rtc_driver = {
+ .remove = __exit_p(at32_rtc_remove),
+ .driver = {
+ .name = "rtc-at32ap700x",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init at32_rtc_init(void)
+{
+ return platform_driver_probe(&at32_rtc_driver, at32_rtc_probe);
+}
+module_init(at32_rtc_init);
+
+static void __exit at32_rtc_exit(void)
+{
+ platform_driver_unregister(&at32_rtc_driver);
+}
+module_exit(at32_rtc_exit);
+
+MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@xxxxxxxxx>");
+MODULE_DESCRIPTION("Real time clock for AVR32 AT32AP700x");
+MODULE_LICENSE("GPL");
--
1.4.4.2
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