rtc: driver for pxa27x and pxa3xx SoC

With PXA27x and above, a new RTC hardware block was added in addition to
the legacy one which is also found on the SA1100 SOC family.  This second
RTC block is called "wristwatch" and "periodic interrupt" and works
independently from the other RTC block.

The driver offers provides :
 - a 1Hz ticking clock
 - a periodic alarm, in the 1Hz to 1000Hz range
 - a one shot alarm

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 493 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-pxa.c b/drivers/rtc/rtc-pxa.c
new file mode 100644
index 0000000..074f356
--- /dev/null
+++ b/drivers/rtc/rtc-pxa.c
@@ -0,0 +1,493 @@
+/*
+ * Real Time Clock interface for XScale PXA27x and PXA3xx
+ *
+ * Copyright (C) 2008 Robert Jarzmik
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/seq_file.h>
+#include <linux/interrupt.h>
+
+#include <asm/io.h>
+
+#define TIMER_FREQ		CLOCK_TICK_RATE
+#define RTC_DEF_DIVIDER		(32768 - 1)
+#define RTC_DEF_TRIM		0
+#define MAXFREQ_PERIODIC	1000
+
+/*
+ * PXA Registers and bits definitions
+ */
+#define RTSR_PICE	(1 << 15)	/* Periodic interrupt count enable */
+#define RTSR_PIALE	(1 << 14)	/* Periodic interrupt Alarm enable */
+#define RTSR_PIAL	(1 << 13)	/* Periodic interrupt detected */
+#define RTSR_SWALE2	(1 << 11)	/* RTC stopwatch alarm2 enable */
+#define RTSR_SWAL2	(1 << 10)	/* RTC stopwatch alarm2 detected */
+#define RTSR_SWALE1	(1 << 9)	/* RTC stopwatch alarm1 enable */
+#define RTSR_SWAL1	(1 << 8)	/* RTC stopwatch alarm1 detected */
+#define RTSR_RDALE2	(1 << 7)	/* RTC alarm2 enable */
+#define RTSR_RDAL2	(1 << 6)	/* RTC alarm2 detected */
+#define RTSR_RDALE1	(1 << 5)	/* RTC alarm1 enable */
+#define RTSR_RDAL1	(1 << 4)	/* RTC alarm1 detected */
+#define RTSR_HZE	(1 << 3)	/* HZ interrupt enable */
+#define RTSR_ALE	(1 << 2)	/* RTC alarm interrupt enable */
+#define RTSR_HZ		(1 << 1)	/* HZ rising-edge detected */
+#define RTSR_AL		(1 << 0)	/* RTC alarm detected */
+#define RTSR_TRIG_MASK	(RTSR_AL | RTSR_HZ | RTSR_RDAL1 | RTSR_RDAL2\
+			 | RTSR_SWAL1 | RTSR_SWAL2)
+#define RYxR_YEAR_S	9
+#define RYxR_YEAR_MASK	(0xfff << RYxR_YEAR_S)
+#define RYxR_MONTH_S	5
+#define RYxR_MONTH_MASK	(0xf << RYxR_MONTH_S)
+#define RYxR_DAY_MASK	0x1f
+#define RDxR_HOUR_S	12
+#define RDxR_HOUR_MASK	(0x1f << RDxR_HOUR_S)
+#define RDxR_MIN_S	6
+#define RDxR_MIN_MASK	(0x3f << RDxR_MIN_S)
+#define RDxR_SEC_MASK	0x3f
+
+#define RTSR		0x08
+#define RTTR		0x0c
+#define RDCR		0x10
+#define RYCR		0x14
+#define RDAR1		0x18
+#define RYAR1		0x1c
+#define RTCPICR		0x34
+#define PIAR		0x38
+
+#define rtc_readl(pxa_rtc, reg)	\
+	__raw_readl((pxa_rtc)->base + (reg))
+#define rtc_writel(pxa_rtc, reg, value)	\
+	__raw_writel((value), (pxa_rtc)->base + (reg))
+
+struct pxa_rtc {
+	struct resource	*ress;
+	void __iomem		*base;
+	int			irq_1Hz;
+	int			irq_Alrm;
+	struct rtc_device	*rtc;
+	spinlock_t		lock;		/* Protects this structure */
+	struct rtc_time		rtc_alarm;
+};
+
+static u32 ryxr_calc(struct rtc_time *tm)
+{
+	return ((tm->tm_year + 1900) << RYxR_YEAR_S)
+		| ((tm->tm_mon + 1) << RYxR_MONTH_S)
+		| tm->tm_mday;
+}
+
+static u32 rdxr_calc(struct rtc_time *tm)
+{
+	return (tm->tm_hour << RDxR_HOUR_S) | (tm->tm_min << RDxR_MIN_S)
+		| tm->tm_sec;
+}
+
+static void tm_calc(u32 rycr, u32 rdcr, struct rtc_time *tm)
+{
+	tm->tm_year = ((rycr & RYxR_YEAR_MASK) >> RYxR_YEAR_S) - 1900;
+	tm->tm_mon = (((rycr & RYxR_MONTH_MASK) >> RYxR_MONTH_S)) - 1;
+	tm->tm_mday = (rycr & RYxR_DAY_MASK);
+	tm->tm_hour = (rdcr & RDxR_HOUR_MASK) >> RDxR_HOUR_S;
+	tm->tm_min = (rdcr & RDxR_MIN_MASK) >> RDxR_MIN_S;
+	tm->tm_sec = rdcr & RDxR_SEC_MASK;
+}
+
+static void rtsr_clear_bits(struct pxa_rtc *pxa_rtc, u32 mask)
+{
+	u32 rtsr;
+
+	rtsr = rtc_readl(pxa_rtc, RTSR);
+	rtsr &= ~RTSR_TRIG_MASK;
+	rtsr &= ~mask;
+	rtc_writel(pxa_rtc, RTSR, rtsr);
+}
+
+static void rtsr_set_bits(struct pxa_rtc *pxa_rtc, u32 mask)
+{
+	u32 rtsr;
+
+	rtsr = rtc_readl(pxa_rtc, RTSR);
+	rtsr &= ~RTSR_TRIG_MASK;
+	rtsr |= mask;
+	rtc_writel(pxa_rtc, RTSR, rtsr);
+}
+
+static irqreturn_t pxa_rtc_irq(int irq, void *dev_id)
+{
+	struct platform_device *pdev = to_platform_device(dev_id);
+	struct pxa_rtc *pxa_rtc = platform_get_drvdata(pdev);
+	u32 rtsr;
+	unsigned long events = 0;
+
+	spin_lock(&pxa_rtc->lock);
+
+	/* clear interrupt sources */
+	rtsr = rtc_readl(pxa_rtc, RTSR);
+	rtc_writel(pxa_rtc, RTSR, rtsr);
+
+	/* temporary disable rtc interrupts */
+	rtsr_clear_bits(pxa_rtc, RTSR_RDALE1 | RTSR_PIALE | RTSR_HZE);
+
+	/* clear alarm interrupt if it has occurred */
+	if (rtsr & RTSR_RDAL1)
+		rtsr &= ~RTSR_RDALE1;
+
+	/* update irq data & counter */
+	if (rtsr & RTSR_RDAL1)
+		events |= RTC_AF | RTC_IRQF;
+	if (rtsr & RTSR_HZ)
+		events |= RTC_UF | RTC_IRQF;
+	if (rtsr & RTSR_PIAL)
+		events |= RTC_PF | RTC_IRQF;
+
+	rtc_update_irq(pxa_rtc->rtc, 1, events);
+
+	/* enable back rtc interrupts */
+	rtc_writel(pxa_rtc, RTSR, rtsr & ~RTSR_TRIG_MASK);
+
+	spin_unlock(&pxa_rtc->lock);
+	return IRQ_HANDLED;
+}
+
+static int pxa_rtc_open(struct device *dev)
+{
+	struct pxa_rtc *pxa_rtc = dev_get_drvdata(dev);
+	int ret;
+
+	ret = request_irq(pxa_rtc->irq_1Hz, pxa_rtc_irq, IRQF_DISABLED,
+			  "rtc 1Hz", dev);
+	if (ret < 0) {
+		dev_err(dev, "can't get irq %i, err %d\n", pxa_rtc->irq_1Hz,
+			ret);
+		goto err_irq_1Hz;
+	}
+	ret = request_irq(pxa_rtc->irq_Alrm, pxa_rtc_irq, IRQF_DISABLED,
+			  "rtc Alrm", dev);
+	if (ret < 0) {
+		dev_err(dev, "can't get irq %i, err %d\n", pxa_rtc->irq_Alrm,
+			ret);
+		goto err_irq_Alrm;
+	}
+
+	return 0;
+
+err_irq_Alrm:
+	free_irq(pxa_rtc->irq_1Hz, dev);
+err_irq_1Hz:
+	return ret;
+}
+
+static void pxa_rtc_release(struct device *dev)
+{
+	struct pxa_rtc *pxa_rtc = dev_get_drvdata(dev);
+
+	spin_lock_irq(&pxa_rtc->lock);
+	rtsr_clear_bits(pxa_rtc, RTSR_PIALE | RTSR_RDALE1 | RTSR_HZE);
+	spin_unlock_irq(&pxa_rtc->lock);
+
+	free_irq(pxa_rtc->irq_Alrm, dev);
+	free_irq(pxa_rtc->irq_1Hz, dev);
+}
+
+static int pxa_periodic_irq_set_freq(struct device *dev, int freq)
+{
+	struct pxa_rtc *pxa_rtc = dev_get_drvdata(dev);
+	int period_ms;
+
+	if (freq < 1 || freq > MAXFREQ_PERIODIC)
+		return -EINVAL;
+
+	period_ms = 1000 / freq;
+	rtc_writel(pxa_rtc, PIAR, period_ms);
+
+	return 0;
+}
+
+static int pxa_periodic_irq_set_state(struct device *dev, int enabled)
+{
+	struct pxa_rtc *pxa_rtc = dev_get_drvdata(dev);
+
+	if (enabled)
+		rtsr_set_bits(pxa_rtc, RTSR_PIALE | RTSR_PICE);
+	else
+		rtsr_clear_bits(pxa_rtc, RTSR_PIALE | RTSR_PICE);
+
+	return 0;
+}
+
+static int pxa_rtc_ioctl(struct device *dev, unsigned int cmd,
+		unsigned long arg)
+{
+	struct pxa_rtc *pxa_rtc = dev_get_drvdata(dev);
+	int ret = 0;
+
+	spin_lock_irq(&pxa_rtc->lock);
+	switch (cmd) {
+	case RTC_AIE_OFF:
+		rtsr_clear_bits(pxa_rtc, RTSR_RDALE1);
+		break;
+	case RTC_AIE_ON:
+		rtsr_set_bits(pxa_rtc, RTSR_RDALE1);
+		break;
+	case RTC_UIE_OFF:
+		rtsr_clear_bits(pxa_rtc, RTSR_HZE);
+		break;
+	case RTC_UIE_ON:
+		rtsr_set_bits(pxa_rtc, RTSR_HZE);
+		break;
+	default:
+		ret = -ENOIOCTLCMD;
+	}
+
+	spin_unlock_irq(&pxa_rtc->lock);
+	return ret;
+}
+
+static int pxa_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct pxa_rtc *pxa_rtc = dev_get_drvdata(dev);
+	u32 rycr, rdcr;
+
+	rycr = rtc_readl(pxa_rtc, RYCR);
+	rdcr = rtc_readl(pxa_rtc, RDCR);
+
+	tm_calc(rycr, rdcr, tm);
+	return 0;
+}
+
+static int pxa_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct pxa_rtc *pxa_rtc = dev_get_drvdata(dev);
+
+	rtc_writel(pxa_rtc, RYCR, ryxr_calc(tm));
+	rtc_writel(pxa_rtc, RDCR, rdxr_calc(tm));
+
+	return 0;
+}
+
+static int pxa_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct pxa_rtc *pxa_rtc = dev_get_drvdata(dev);
+	u32 rtsr, ryar, rdar;
+
+	ryar = rtc_readl(pxa_rtc, RYAR1);
+	rdar = rtc_readl(pxa_rtc, RDAR1);
+	tm_calc(ryar, rdar, &alrm->time);
+
+	rtsr = rtc_readl(pxa_rtc, RTSR);
+	alrm->enabled = (rtsr & RTSR_RDALE1) ? 1 : 0;
+	alrm->pending = (rtsr & RTSR_RDAL1) ? 1 : 0;
+	return 0;
+}
+
+static int pxa_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+	struct pxa_rtc *pxa_rtc = dev_get_drvdata(dev);
+	u32 rtsr;
+
+	spin_lock_irq(&pxa_rtc->lock);
+
+	rtc_writel(pxa_rtc, RYAR1, ryxr_calc(&alrm->time));
+	rtc_writel(pxa_rtc, RDAR1, rdxr_calc(&alrm->time));
+
+	rtsr = rtc_readl(pxa_rtc, RTSR);
+	if (alrm->enabled)
+		rtsr |= RTSR_RDALE1;
+	else
+		rtsr &= ~RTSR_RDALE1;
+	rtc_writel(pxa_rtc, RTSR, rtsr);
+
+	spin_unlock_irq(&pxa_rtc->lock);
+
+	return 0;
+}
+
+static int pxa_rtc_proc(struct device *dev, struct seq_file *seq)
+{
+	struct pxa_rtc *pxa_rtc = dev_get_drvdata(dev);
+
+	seq_printf(seq, "trim/divider\t: 0x%08x\n", rtc_readl(pxa_rtc, RTTR));
+	seq_printf(seq, "update_IRQ\t: %s\n",
+		   (rtc_readl(pxa_rtc, RTSR) & RTSR_HZE) ? "yes" : "no");
+	seq_printf(seq, "periodic_IRQ\t: %s\n",
+		   (rtc_readl(pxa_rtc, RTSR) & RTSR_PIALE) ? "yes" : "no");
+	seq_printf(seq, "periodic_freq\t: %u\n", rtc_readl(pxa_rtc, PIAR));
+
+	return 0;
+}
+
+static const struct rtc_class_ops pxa_rtc_ops = {
+	.open = pxa_rtc_open,
+	.release = pxa_rtc_release,
+	.ioctl = pxa_rtc_ioctl,
+	.read_time = pxa_rtc_read_time,
+	.set_time = pxa_rtc_set_time,
+	.read_alarm = pxa_rtc_read_alarm,
+	.set_alarm = pxa_rtc_set_alarm,
+	.proc = pxa_rtc_proc,
+	.irq_set_state = pxa_periodic_irq_set_state,
+	.irq_set_freq = pxa_periodic_irq_set_freq,
+};
+
+static int __devinit pxa_rtc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct pxa_rtc *pxa_rtc;
+	int ret;
+	u32 rttr;
+
+	ret = -ENOMEM;
+	pxa_rtc = kzalloc(sizeof(struct pxa_rtc), GFP_KERNEL);
+	if (!pxa_rtc)
+		goto err_alloc;
+
+	ret = -ENXIO;
+	pxa_rtc->ress = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!pxa_rtc->ress) {
+		dev_err(dev, "No I/O memory resource defined\n");
+		goto err_ress;
+	}
+
+	pxa_rtc->irq_1Hz = platform_get_irq(pdev, 0);
+	if (pxa_rtc->irq_1Hz < 0) {
+		dev_err(dev, "No 1Hz IRQ resource defined\n");
+		goto err_ress;
+	}
+	pxa_rtc->irq_Alrm = platform_get_irq(pdev, 1);
+	if (pxa_rtc->irq_Alrm < 0) {
+		dev_err(dev, "No alarm IRQ resource defined\n");
+		goto err_ress;
+	}
+
+	pxa_rtc->rtc = rtc_device_register(pdev->name, &pdev->dev, &pxa_rtc_ops,
+					   THIS_MODULE);
+	ret = PTR_ERR(pxa_rtc->rtc);
+	if (IS_ERR(pxa_rtc->rtc)) {
+		dev_err(dev, "Failed to register RTC device -> %d\n", ret);
+		goto err_rtc_reg;
+	}
+
+	spin_lock_init(&pxa_rtc->lock);
+	platform_set_drvdata(pdev, pxa_rtc);
+
+	ret = -ENOMEM;
+	pxa_rtc->base = ioremap(pxa_rtc->ress->start,
+				pxa_rtc->ress->end - pxa_rtc->ress->start + 1);
+	if (!pxa_rtc->base) {
+		dev_err(&pdev->dev, "Unable to map pxa RTC I/O memory\n");
+		goto err_map;
+	}
+
+	/*
+	 * If the clock divider is uninitialized then reset it to the
+	 * default value to get the 1Hz clock.
+	 */
+	if (rtc_readl(pxa_rtc, RTTR) == 0) {
+		rttr = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16);
+		rtc_writel(pxa_rtc, RTTR, rttr);
+		dev_warn(dev, "warning: initializing default clock"
+			 " divider/trim value\n");
+	}
+
+	rtsr_clear_bits(pxa_rtc, RTSR_PIALE | RTSR_RDALE1 | RTSR_HZE);
+	device_init_wakeup(dev, 1);
+
+	return 0;
+
+err_map:
+	platform_set_drvdata(pdev, NULL);
+	rtc_device_unregister(pxa_rtc->rtc);
+err_rtc_reg:
+err_ress:
+	kfree(pxa_rtc);
+err_alloc:
+	return ret;
+}
+
+static int __devexit pxa_rtc_remove(struct platform_device *pdev)
+{
+	struct pxa_rtc *pxa_rtc = platform_get_drvdata(pdev);
+
+	spin_lock_irq(&pxa_rtc->lock);
+	iounmap(pxa_rtc->base);
+	pxa_rtc->base = NULL;
+	platform_set_drvdata(pdev, NULL);
+	spin_unlock_irq(&pxa_rtc->lock);
+
+	rtc_device_unregister(pxa_rtc->rtc);
+	kfree(pxa_rtc);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int pxa_rtc_suspend(struct platform_device *pdev, pm_message_t state)
+{
+	struct pxa_rtc *pxa_rtc = platform_get_drvdata(pdev);
+
+	if (device_may_wakeup(&pdev->dev))
+		enable_irq_wake(pxa_rtc->irq_Alrm);
+	return 0;
+}
+
+static int pxa_rtc_resume(struct platform_device *pdev)
+{
+	struct pxa_rtc *pxa_rtc = platform_get_drvdata(pdev);
+
+	if (device_may_wakeup(&pdev->dev))
+		disable_irq_wake(pxa_rtc->irq_Alrm);
+	return 0;
+}
+#else
+#define pxa_rtc_suspend	NULL
+#define pxa_rtc_resume	NULL
+#endif
+
+static struct platform_driver pxa_rtc_driver = {
+	.probe		= pxa_rtc_probe,
+	.remove		= __exit_p(pxa_rtc_remove),
+	.suspend	= pxa_rtc_suspend,
+	.resume		= pxa_rtc_resume,
+	.driver		= {
+		.name		= "pxa-rtc",
+	},
+};
+
+static int __init pxa_rtc_init(void)
+{
+	if (cpu_is_pxa27x() || cpu_is_pxa3xx())
+		return platform_driver_register(&pxa_rtc_driver);
+
+	return -ENODEV;
+}
+
+static void __exit pxa_rtc_exit(void)
+{
+	platform_driver_unregister(&pxa_rtc_driver);
+}
+
+module_init(pxa_rtc_init);
+module_exit(pxa_rtc_exit);
+
+MODULE_AUTHOR("Robert Jarzmik");
+MODULE_DESCRIPTION("PXA27x/PXA3xx Realtime Clock Driver (RTC)");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:pxa-rtc");