Re: [PATCH 5/6 v4] rtc: Add support for the RTC in VIA VT8500 andcompatibles

From: Lars-Peter Clausen
Date: Wed Nov 24 2010 - 14:24:23 EST

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Alexey Charkov wrote:
> 2010/11/14 Alexey Charkov <alchark@xxxxxxxxx>:
>> 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@xxxxxxxxx>
>> ---
>>
>> Thanks for the comments, Lars! This version implements the latest
>> ones as well.
>>
>> Best regards,
>> Alexey
>>
>> drivers/rtc/Kconfig | 7 +
>> drivers/rtc/Makefile | 1 +
>> drivers/rtc/rtc-vt8500.c | 359 ++++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 367 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..cdf4f63
>> --- /dev/null
>> +++ b/drivers/rtc/rtc-vt8500.c
>> @@ -0,0 +1,359 @@
>> +/*
>> + * drivers/rtc/rtc-vt8500.c
>> + *
>> + * Copyright (C) 2010 Alexey Charkov <alchark@xxxxxxxxx>
>> + *
>> + * 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;
>> + 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;
>> +
>> + if (!readl(vt8500_rtc->regbase + VT8500_RTC_ST)) {
>> + dev_info(dev, "Clock not set!");
>> + return -EINVAL;
>> + }
>> + 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 rtc_valid_tm(tm);
>> +}
>> +
>> +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 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;
>> + 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);
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + if (!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;
>> + }
>> +
>> + res = request_mem_region(res->start, resource_size(res), "vt8500-rtc");
>> + if (res == NULL) {
>> + dev_err(&pdev->dev, "failed to request I/O memory\n");
>> + ret = -EBUSY;
>> + goto err_free;
>> + }
>> +
>> + 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");
>> + 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(res->start, resource_size(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);
>> + struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +
>> + 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(res->start, resource_size(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@xxxxxxxxx>");
>> +MODULE_DESCRIPTION("VIA VT8500 SoC Realtime Clock Driver (RTC)");
>> +MODULE_LICENSE("GPL");
>> +MODULE_ALIAS("platform:vt8500-rtc");
>> --
>> 1.7.3.2
>>
>>
>
> Any further comments about this code? Could it be merged now?
>
> Lars, sorry for double-posting this (forgot to CC the lists and others
> last time).

Looks good to me, except one small thing: request_mem_region allocates the resource
struct it returns. You should pass the same struct to release_mem_region to free it
again.
When that is fixed feel free to add a
Reviewed-By: Lars-Peter Clausen <lars@xxxxxxxxxx>

>
> Thanks,
> Alexey

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Next message: Jeremy Fitzhardinge: "Re: [thiscpuops upgrade 10/10] Lockless (and preemptless) fastpathsfor slub"
Previous message: Stefano Stabellini: "[PATCH v2] Use PHYSDEVOP_get_free_pirq to implementfind_unbound_pirq"
Next in thread: Alexey Charkov: "[PATCH 5/6 v5] rtc: Add support for the RTC in VIA VT8500 andcompatibles"
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