[PATCH 5/6 v5] rtc: Add support for the RTC in VIA VT8500 and compatibles
Alexey Charkov
alchark at gmail.com
Wed Nov 24 17:47:52 EST 2010
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 at gmail.com>
---
This fixes the issue with releasing the resource mentioned by Lars.
In addition, I've fixed the years range to reflect what the hardware seems
to actually expect (2000-2199 instead of 1900-... as implied by prior code).
In the process, it turned out that using rtc_valid_tm() when reading time
precludes any obvious recovery path if for some reason the hardware contains
garbage at kernel initialization: `hwclock -w` tries to read time before
updating, and fails. However, bad time values are handled gracefully by the
userspace, so I just put in 'return 0' there. In-kernel hctosys also checks
the returned time, so this seems to be valid behaviour.
Reading alarm values still returns through rtc_valid_tm().
Thanks,
Alexey
drivers/rtc/Kconfig | 7 +
drivers/rtc/Makefile | 1 +
drivers/rtc/rtc-vt8500.c | 366 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 374 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..b8bc862
--- /dev/null
+++ b/drivers/rtc/rtc-vt8500.c
@@ -0,0 +1,366 @@
+/*
+ * drivers/rtc/rtc-vt8500.c
+ *
+ * Copyright (C) 2010 Alexey Charkov <alchark at 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)
+
+#define VT8500_RTC_CR_ENABLE (1 << 0) /* Enable RTC */
+#define VT8500_RTC_CR_24H (1 << 1) /* 24h time format */
+#define VT8500_RTC_CR_SM_ENABLE (1 << 2) /* Enable periodic irqs */
+#define VT8500_RTC_CR_SM_SEC (1 << 3) /* 0: 1Hz/60, 1: 1Hz */
+#define VT8500_RTC_CR_CALIB (1 << 4) /* Enable calibration */
+
+struct vt8500_rtc {
+ void __iomem *regbase;
+ struct resource *res;
+ int irq_alarm;
+ int irq_hz;
+ struct rtc_device *rtc;
+ spinlock_t lock; /* Protects this structure */
+};
+
+static irqreturn_t vt8500_rtc_irq(int irq, void *dev_id)
+{
+ struct vt8500_rtc *vt8500_rtc = dev_id;
+ 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);
+
+ spin_unlock(&vt8500_rtc->lock);
+
+ 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);
+
+ return IRQ_HANDLED;
+}
+
+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)
+ + ((date >> DATE_CENTURY_S) & 1 ? 200 : 100);
+ 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);
+
+ if (tm->tm_year < 100) {
+ dev_warn(dev, "Only years 2000-2199 are supported by the "
+ "hardware!\n");
+ return -EINVAL;
+ }
+
+ writel((bin2bcd(tm->tm_year - 100) << 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 rtc_valid_tm(&alrm->time);
+}
+
+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_alarm_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
+ unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_AS);
+
+ if (enabled)
+ tmp |= ALARM_ENABLE_MASK;
+ else
+ tmp &= ~ALARM_ENABLE_MASK;
+
+ writel(tmp, vt8500_rtc->regbase + VT8500_RTC_AS);
+ return 0;
+}
+
+static int vt8500_update_irq_enable(struct device *dev, unsigned int enabled)
+{
+ struct vt8500_rtc *vt8500_rtc = dev_get_drvdata(dev);
+ unsigned long tmp = readl(vt8500_rtc->regbase + VT8500_RTC_CR);
+
+ if (enabled)
+ tmp |= VT8500_RTC_CR_SM_SEC | VT8500_RTC_CR_SM_ENABLE;
+ else
+ tmp &= ~VT8500_RTC_CR_SM_ENABLE;
+
+ writel(tmp, vt8500_rtc->regbase + VT8500_RTC_CR);
+ return 0;
+}
+
+static const struct rtc_class_ops vt8500_rtc_ops = {
+ .read_time = vt8500_rtc_read_time,
+ .set_time = vt8500_rtc_set_time,
+ .read_alarm = vt8500_rtc_read_alarm,
+ .set_alarm = vt8500_rtc_set_alarm,
+ .alarm_irq_enable = vt8500_alarm_irq_enable,
+ .update_irq_enable = vt8500_update_irq_enable,
+};
+
+static int __devinit vt8500_rtc_probe(struct platform_device *pdev)
+{
+ struct vt8500_rtc *vt8500_rtc;
+ 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);
+
+ vt8500_rtc->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!vt8500_rtc->res) {
+ dev_err(&pdev->dev, "No I/O memory resource defined\n");
+ ret = -ENXIO;
+ goto err_free;
+ }
+
+ vt8500_rtc->irq_alarm = platform_get_irq(pdev, 0);
+ if (vt8500_rtc->irq_alarm < 0) {
+ dev_err(&pdev->dev, "No alarm IRQ resource defined\n");
+ ret = -ENXIO;
+ goto err_free;
+ }
+
+ vt8500_rtc->irq_hz = platform_get_irq(pdev, 1);
+ if (vt8500_rtc->irq_hz < 0) {
+ dev_err(&pdev->dev, "No 1Hz IRQ resource defined\n");
+ ret = -ENXIO;
+ goto err_free;
+ }
+
+ vt8500_rtc->res = request_mem_region(vt8500_rtc->res->start,
+ resource_size(vt8500_rtc->res),
+ "vt8500-rtc");
+ if (vt8500_rtc->res == NULL) {
+ dev_err(&pdev->dev, "failed to request I/O memory\n");
+ ret = -EBUSY;
+ goto err_free;
+ }
+
+ vt8500_rtc->regbase = ioremap(vt8500_rtc->res->start,
+ resource_size(vt8500_rtc->res));
+ if (!vt8500_rtc->regbase) {
+ dev_err(&pdev->dev, "Unable to map RTC I/O memory\n");
+ ret = -EBUSY;
+ goto err_release;
+ }
+
+ /* Enable the second/minute interrupt generation and enable RTC */
+ writel(VT8500_RTC_CR_ENABLE | VT8500_RTC_CR_24H
+ | VT8500_RTC_CR_SM_ENABLE | VT8500_RTC_CR_SM_SEC,
+ vt8500_rtc->regbase + VT8500_RTC_CR);
+
+ vt8500_rtc->rtc = rtc_device_register("vt8500-rtc", &pdev->dev,
+ &vt8500_rtc_ops, THIS_MODULE);
+ if (IS_ERR(vt8500_rtc->rtc)) {
+ ret = PTR_ERR(vt8500_rtc->rtc);
+ dev_err(&pdev->dev,
+ "Failed to register RTC device -> %d\n", ret);
+ goto err_unmap;
+ }
+
+ ret = request_irq(vt8500_rtc->irq_hz, vt8500_rtc_irq, 0,
+ "rtc 1Hz", vt8500_rtc);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "can't get irq %i, err %d\n",
+ vt8500_rtc->irq_hz, ret);
+ goto err_unreg;
+ }
+
+ ret = request_irq(vt8500_rtc->irq_alarm, vt8500_rtc_irq, 0,
+ "rtc alarm", vt8500_rtc);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "can't get irq %i, err %d\n",
+ vt8500_rtc->irq_alarm, ret);
+ goto err_free_hz;
+ }
+
+ return 0;
+
+err_free_hz:
+ free_irq(vt8500_rtc->irq_hz, vt8500_rtc);
+err_unreg:
+ rtc_device_unregister(vt8500_rtc->rtc);
+err_unmap:
+ iounmap(vt8500_rtc->regbase);
+err_release:
+ release_mem_region(vt8500_rtc->res->start,
+ resource_size(vt8500_rtc->res));
+err_free:
+ kfree(vt8500_rtc);
+ return ret;
+}
+
+static int __devexit vt8500_rtc_remove(struct platform_device *pdev)
+{
+ struct vt8500_rtc *vt8500_rtc = platform_get_drvdata(pdev);
+
+ free_irq(vt8500_rtc->irq_alarm, vt8500_rtc);
+ free_irq(vt8500_rtc->irq_hz, vt8500_rtc);
+
+ rtc_device_unregister(vt8500_rtc->rtc);
+
+ /* Disable alarm matching */
+ writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
+ iounmap(vt8500_rtc->regbase);
+ release_mem_region(vt8500_rtc->res->start,
+ resource_size(vt8500_rtc->res));
+
+ kfree(vt8500_rtc);
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+static struct platform_driver vt8500_rtc_driver = {
+ .probe = vt8500_rtc_probe,
+ .remove = __devexit_p(vt8500_rtc_remove),
+ .driver = {
+ .name = "vt8500-rtc",
+ .owner = THIS_MODULE,
+ },
+};
+
+static int __init vt8500_rtc_init(void)
+{
+ return platform_driver_register(&vt8500_rtc_driver);
+}
+module_init(vt8500_rtc_init);
+
+static void __exit vt8500_rtc_exit(void)
+{
+ platform_driver_unregister(&vt8500_rtc_driver);
+}
+module_exit(vt8500_rtc_exit);
+
+MODULE_AUTHOR("Alexey Charkov <alchark at gmail.com>");
+MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:vt8500-rtc");
--
1.7.3.2
More information about the linux-arm-kernel
mailing list