Subject: [PATCH 5/6 v4] rtc: Add support for the RTC in VIA VT8500 and compatibles

From: [email-masked] (Lars-Peter Clausen)
Date: Wed, 24 Nov 2010 20:23:55 +0100

Alexey Charkov wrote:
> 2010/11/14 Alexey Charkov <[email-masked]>:
>> 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 <[email-masked]>
>> ---
>>
>> 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 <[email-masked]>
>> + *
>> + * 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 <[email-masked]>");
>> +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 <[email-masked]>

> Thanks,
> Alexey