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Subject[PATCH 5/6 v2] rtc: Add support for the RTC in VIA VT8500 and compatibles
Date
This adds a driver for the RTC devices in VIA and WonderMedia
Systems-on-Chip. Alarm, 1Hz interrupts, reading and setting time
are supported.

Signed-off-by: Alexey Charkov <alchark@gmail.com>
---
Please review and (if appropriate) commit to a relevant git tree for
further integration in 2.6.38.

Compared to the previous submission, this code just contains a rebase
against the latest changes introduced in 2.6.37 merge window.

Relevant platform definitions are introduced by PATCH 1/6 in this series,
so one would need that to make use of this code.

Due credits go to the community for providing feedback, advice and
testing.

drivers/rtc/Kconfig | 7 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-vt8500.c | 363 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 371 insertions(+), 0 deletions(-)
create mode 100644 drivers/rtc/rtc-vt8500.c
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index 2883428..27ed129 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -865,6 +865,13 @@ config RTC_DRV_PXA
This RTC driver uses PXA RTC registers available since pxa27x
series (RDxR, RYxR) instead of legacy RCNR, RTAR.

+config RTC_DRV_VT8500
+ tristate "VIA/WonderMedia 85xx SoC RTC"
+ depends on ARCH_VT8500
+ help
+ If you say Y here you will get access to the real time clock
+ built into your VIA VT8500 SoC or its relatives.
+

config RTC_DRV_SUN4V
bool "SUN4V Hypervisor RTC"
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index 4c2832d..1a354e1 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -97,6 +97,7 @@ obj-$(CONFIG_RTC_DRV_TWL4030) += rtc-twl.o
obj-$(CONFIG_RTC_DRV_TX4939) += rtc-tx4939.o
obj-$(CONFIG_RTC_DRV_V3020) += rtc-v3020.o
obj-$(CONFIG_RTC_DRV_VR41XX) += rtc-vr41xx.o
+obj-$(CONFIG_RTC_DRV_VT8500) += rtc-vt8500.o
obj-$(CONFIG_RTC_DRV_WM831X) += rtc-wm831x.o
obj-$(CONFIG_RTC_DRV_WM8350) += rtc-wm8350.o
obj-$(CONFIG_RTC_DRV_X1205) += rtc-x1205.o
diff --git a/drivers/rtc/rtc-vt8500.c b/drivers/rtc/rtc-vt8500.c
new file mode 100644
index 0000000..7260c95
--- /dev/null
+++ b/drivers/rtc/rtc-vt8500.c
@@ -0,0 +1,363 @@
+/*
+ * drivers/rtc/rtc-vt8500.c
+ *
+ * Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
+ *
+ * Based on rtc-pxa.c
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/rtc.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/bcd.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+/*
+ * Register definitions
+ */
+#define VT8500_RTC_TS 0x00 /* Time set */
+#define VT8500_RTC_DS 0x04 /* Date set */
+#define VT8500_RTC_AS 0x08 /* Alarm set */
+#define VT8500_RTC_CR 0x0c /* Control */
+#define VT8500_RTC_TR 0x10 /* Time read */
+#define VT8500_RTC_DR 0x14 /* Date read */
+#define VT8500_RTC_WS 0x18 /* Write status */
+#define VT8500_RTC_CL 0x20 /* Calibration */
+#define VT8500_RTC_IS 0x24 /* Interrupt status */
+#define VT8500_RTC_ST 0x28 /* Status */
+
+#define INVALID_TIME_BIT (1 << 31)
+
+#define DATE_CENTURY_S 19
+#define DATE_YEAR_S 11
+#define DATE_YEAR_MASK (0xff << DATE_YEAR_S)
+#define DATE_MONTH_S 6
+#define DATE_MONTH_MASK (0x1f << DATE_MONTH_S)
+#define DATE_DAY_MASK 0x3f
+
+#define TIME_DOW_S 20
+#define TIME_DOW_MASK (0x07 << TIME_DOW_S)
+#define TIME_HOUR_S 14
+#define TIME_HOUR_MASK (0x3f << TIME_HOUR_S)
+#define TIME_MIN_S 7
+#define TIME_MIN_MASK (0x7f << TIME_MIN_S)
+#define TIME_SEC_MASK 0x7f
+
+#define ALARM_DAY_S 20
+#define ALARM_DAY_MASK (0x3f << ALARM_DAY_S)
+
+#define ALARM_DAY_BIT (1 << 29)
+#define ALARM_HOUR_BIT (1 << 28)
+#define ALARM_MIN_BIT (1 << 27)
+#define ALARM_SEC_BIT (1 << 26)
+
+#define ALARM_ENABLE_MASK (ALARM_DAY_BIT \
+ | ALARM_HOUR_BIT \
+ | ALARM_MIN_BIT \
+ | ALARM_SEC_BIT)
+
+struct vt8500_rtc {
+ void __iomem *regbase;
+ int irq_alarm;
+ int irq_hz;
+ struct rtc_device *rtc;
+ spinlock_t lock; /* Protects this structure */
+ struct rtc_time rtc_alarm;
+};
+
+static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
+{
+ struct platform_device *pdev = to_platform_device(dev_id);
+ struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
+ u32 isr;
+ unsigned long events = 0;
+
+ spin_lock(&vt8500_rtc->lock);
+
+ /* clear interrupt sources */
+ isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
+ writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);
+
+ if (isr & 1)
+ events |= RTC_AF | RTC_IRQF;
+
+ /* Only second/minute interrupts are supported */
+ if (isr & 2)
+ events |= RTC_UF | RTC_IRQF;
+
+ rtc_update_irq(vt8500_rtc->rtc, 1, events);
+
+ spin_unlock(&vt8500_rtc->lock);
+ return IRQ_HANDLED;
+}
+
+static int vt8500_rtc_open(struct device *dev)
+{
+ struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
+ int ret;
+
+ ret = request_irq(vt8500_rtc->irq_hz, vt8500_rtc_irq, IRQF_DISABLED,
+ "rtc 1Hz", dev);
+ if (ret < 0) {
+ dev_err(dev, "can't get irq %i, err %d\n", vt8500_rtc->irq_hz,
+ ret);
+ goto err_irq_hz;
+ }
+ ret = request_irq(vt8500_rtc->irq_alarm, vt8500_rtc_irq, IRQF_DISABLED,
+ "rtc alarm", dev);
+ if (ret < 0) {
+ dev_err(dev, "can't get irq %i, err %d\n",
+ vt8500_rtc->irq_alarm, ret);
+ goto err_irq_alarm;
+ }
+ return 0;
+
+err_irq_alarm:
+ free_irq(vt8500_rtc->irq_hz, dev);
+err_irq_hz:
+ return ret;
+}
+
+static void vt8500_rtc_release(struct device *dev)
+{
+ struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
+
+ spin_lock_irq(&vt8500_rtc->lock);
+ /* Disable alarm matching */
+ writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
+ spin_unlock_irq(&vt8500_rtc->lock);
+
+ free_irq(vt8500_rtc->irq_alarm, dev);
+ free_irq(vt8500_rtc->irq_hz, dev);
+}
+
+static int vt8500_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+ struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
+ u32 date, time;
+
+ date = readl(vt8500_rtc->regbase + VT8500_RTC_DR);
+ time = readl(vt8500_rtc->regbase + VT8500_RTC_TR);
+
+ tm->tm_sec = bcd2bin(time & TIME_SEC_MASK);
+ tm->tm_min = bcd2bin((time & TIME_MIN_MASK) >> TIME_MIN_S);
+ tm->tm_hour = bcd2bin((time & TIME_HOUR_MASK) >> TIME_HOUR_S);
+ tm->tm_mday = bcd2bin(date & DATE_DAY_MASK);
+ tm->tm_mon = bcd2bin((date & DATE_MONTH_MASK) >> DATE_MONTH_S);
+ tm->tm_year = bcd2bin((date & DATE_YEAR_MASK) >> DATE_YEAR_S);
+ tm->tm_wday = (time & TIME_DOW_MASK) >> TIME_DOW_S;
+
+ return 0;
+}
+
+static int vt8500_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+ struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
+
+ writel((bin2bcd(tm->tm_year) << DATE_YEAR_S)
+ | (bin2bcd(tm->tm_mon) << DATE_MONTH_S)
+ | (bin2bcd(tm->tm_mday)),
+ vt8500_rtc->regbase + VT8500_RTC_DS);
+ writel((bin2bcd(tm->tm_wday) << TIME_DOW_S)
+ | (bin2bcd(tm->tm_hour) << TIME_HOUR_S)
+ | (bin2bcd(tm->tm_min) << TIME_MIN_S)
+ | (bin2bcd(tm->tm_sec)),
+ vt8500_rtc->regbase + VT8500_RTC_TS);
+
+ return 0;
+}
+
+static int vt8500_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
+ u32 isr, alarm;
+
+ alarm = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
+ isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
+
+ alrm->time.tm_mday = bcd2bin((alarm & ALARM_DAY_MASK) >> ALARM_DAY_S);
+ alrm->time.tm_hour = bcd2bin((alarm & TIME_HOUR_MASK) >> TIME_HOUR_S);
+ alrm->time.tm_min = bcd2bin((alarm & TIME_MIN_MASK) >> TIME_MIN_S);
+ alrm->time.tm_sec = bcd2bin((alarm & TIME_SEC_MASK));
+
+ alrm->enabled = (alarm & ALARM_ENABLE_MASK) ? 1 : 0;
+
+ alrm->pending = (isr & 1) ? 1 : 0;
+ return 0;
+}
+
+static int vt8500_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
+{
+ struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
+
+ writel((alrm->enabled ? ALARM_ENABLE_MASK : 0)
+ | (bin2bcd(alrm->time.tm_mday) << ALARM_DAY_S)
+ | (bin2bcd(alrm->time.tm_hour) << TIME_HOUR_S)
+ | (bin2bcd(alrm->time.tm_min) << TIME_MIN_S)
+ | (bin2bcd(alrm->time.tm_sec)),
+ vt8500_rtc->regbase + VT8500_RTC_AS);
+
+ return 0;
+}
+
+static int vt8500_rtc_ioctl(struct device *dev, unsigned int cmd,
+ unsigned long arg)
+{
+ struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
+ int ret = 0;
+ unsigned long tmp;
+
+ spin_lock_irq(&vt8500_rtc->lock);
+ switch (cmd) {
+ case RTC_AIE_OFF:
+ tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
+ writel(tmp & ~ALARM_ENABLE_MASK,
+ vt8500_rtc->regbase + VT8500_RTC_AS);
+ break;
+ case RTC_AIE_ON:
+ tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
+ writel(tmp | ALARM_ENABLE_MASK,
+ vt8500_rtc->regbase + VT8500_RTC_AS);
+ break;
+ case RTC_UIE_OFF:
+ tmp = readl(vt8500_rtc->regbase + VT8500_RTC_CR);
+ writel(tmp & ~(1 << 2),
+ vt8500_rtc->regbase + VT8500_RTC_CR);
+ break;
+ case RTC_UIE_ON:
+ tmp = readl(vt8500_rtc->regbase + VT8500_RTC_CR);
+ writel(tmp | ((1 << 3) | (1 << 2)),
+ vt8500_rtc->regbase + VT8500_RTC_CR);
+ break;
+ default:
+ ret = -ENOIOCTLCMD;
+ }
+
+ spin_unlock_irq(&vt8500_rtc->lock);
+ return ret;
+}
+
+static const struct rtc_class_ops vt8500_rtc_ops = {
+ .open = vt8500_rtc_open,
+ .release = vt8500_rtc_release,
+ .ioctl = vt8500_rtc_ioctl,
+ .read_time = vt8500_rtc_read_time,
+ .set_time = vt8500_rtc_set_time,
+ .read_alarm = vt8500_rtc_read_alarm,
+ .set_alarm = vt8500_rtc_set_alarm,
+};
+
+static int __init vt8500_rtc_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct vt8500_rtc *vt8500_rtc;
+ struct resource *res;
+ int ret;
+
+ vt8500_rtc = kzalloc(sizeof(struct vt8500_rtc), GFP_KERNEL);
+ if (!vt8500_rtc)
+ return -ENOMEM;
+
+ spin_lock_init(&vt8500_rtc->lock);
+ platform_set_drvdata(pdev, vt8500_rtc);
+
+ ret = -ENXIO;
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(dev, "No I/O memory resource defined\n");
+ goto err_map;
+ }
+
+ vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
+ if (vt8500_rtc->irq_alarm < 0) {
+ dev_err(dev, "No alarm IRQ resource defined\n");
+ goto err_map;
+ }
+
+ vt8500_rtc->irq_hz = platform_get_irq(pdev, 1);
+ if (vt8500_rtc->irq_hz < 0) {
+ dev_err(dev, "No 1Hz IRQ resource defined\n");
+ goto err_map;
+ }
+
+ ret = -ENOMEM;
+ vt8500_rtc->regbase = ioremap(res->start, resource_size(res));
+ if (!vt8500_rtc->regbase) {
+ dev_err(&pdev->dev, "Unable to map RTC I/O memory\n");
+ goto err_map;
+ }
+
+ /* Enable the second/minute interrupt generation and enable RTC */
+ writel((1 << 3) | (1 << 2) | 1, vt8500_rtc->regbase + VT8500_RTC_CR);
+
+ vt8500_rtc->rtc = rtc_device_register("vt8500-rtc", &pdev->dev,
+ &vt8500_rtc_ops, THIS_MODULE);
+ ret = PTR_ERR(vt8500_rtc->rtc);
+ if (IS_ERR(vt8500_rtc->rtc)) {
+ dev_err(dev, "Failed to register RTC device -> %d\n", ret);
+ goto err_rtc_reg;
+ }
+
+ device_init_wakeup(dev, 1);
+
+ return 0;
+
+err_rtc_reg:
+ iounmap(vt8500_rtc->regbase);
+err_map:
+ kfree(vt8500_rtc);
+ return ret;
+}
+
+static int __exit vt8500_rtc_remove(struct platform_device *pdev)
+{
+ struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
+
+ rtc_device_unregister(vt8500_rtc->rtc);
+
+ spin_lock_irq(&vt8500_rtc->lock);
+ iounmap(vt8500_rtc->regbase);
+ spin_unlock_irq(&vt8500_rtc->lock);
+
+ kfree(vt8500_rtc);
+
+ return 0;
+}
+
+static struct platform_driver vt8500_rtc_driver = {
+ .probe = vt8500_rtc_probe,
+ .remove = __exit_p(vt8500_rtc_remove),
+ .driver = {
+ .name = "vt8500-rtc"
+ },
+};
+
+static int __init vt8500_rtc_init(void)
+{
+ return platform_driver_register(&vt8500_rtc_driver);
+}
+
+static void __exit vt8500_rtc_exit(void)
+{
+ platform_driver_unregister(&vt8500_rtc_driver);
+}
+
+module_init(vt8500_rtc_init);
+module_exit(vt8500_rtc_exit);
+
+MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
+MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:vt8500-rtc");
--
1.7.3.2


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