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    SubjectRe: [rtc-linux] [RFC][PATCH 15/26] RTC: Add JZ4740 RTC driver
    From
    2010/6/3 Lars-Peter Clausen <lars@metafoo.de>:
    > This patch adds support for the RTC unit on JZ4740 SoCs.
    >
    > Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
    > Cc: Alessandro Zummo <a.zummo@towertech.it>
    > Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
    > Cc: rtc-linux@googlegroups.com
    > ---
    >  drivers/rtc/Kconfig      |   11 ++
    >  drivers/rtc/Makefile     |    1 +
    >  drivers/rtc/rtc-jz4740.c |  344 ++++++++++++++++++++++++++++++++++++++++++++++
    >  3 files changed, 356 insertions(+), 0 deletions(-)
    >  create mode 100644 drivers/rtc/rtc-jz4740.c
    >
    > diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
    > index 10ba12c..d0ed7e6 100644
    > --- a/drivers/rtc/Kconfig
    > +++ b/drivers/rtc/Kconfig
    > @@ -905,4 +905,15 @@ config RTC_DRV_MPC5121
    >          This driver can also be built as a module. If so, the module
    >          will be called rtc-mpc5121.
    >
    > +config RTC_DRV_JZ4740
    > +       tristate "Ingenic JZ4740 SoC"
    > +       depends on RTC_CLASS
    > +       depends on MACH_JZ4740
    > +       help
    > +         If you say yes here you get support for the Ingenic JZ4740 SoC RTC
    > +         controller.
    > +
    > +         This driver can also be buillt as a module. If so, the module
    > +         will be called rtc-jz4740.
    > +
    >  endif # RTC_CLASS
    > diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
    > index 5adbba7..fedf9bb 100644
    > --- a/drivers/rtc/Makefile
    > +++ b/drivers/rtc/Makefile
    > @@ -47,6 +47,7 @@ obj-$(CONFIG_RTC_DRV_EP93XX)  += rtc-ep93xx.o
    >  obj-$(CONFIG_RTC_DRV_FM3130)   += rtc-fm3130.o
    >  obj-$(CONFIG_RTC_DRV_GENERIC)  += rtc-generic.o
    >  obj-$(CONFIG_RTC_DRV_ISL1208)  += rtc-isl1208.o
    > +obj-$(CONFIG_RTC_DRV_JZ4740)   += rtc-jz4740.o
    >  obj-$(CONFIG_RTC_DRV_M41T80)   += rtc-m41t80.o
    >  obj-$(CONFIG_RTC_DRV_M41T94)   += rtc-m41t94.o
    >  obj-$(CONFIG_RTC_DRV_M48T35)   += rtc-m48t35.o
    > diff --git a/drivers/rtc/rtc-jz4740.c b/drivers/rtc/rtc-jz4740.c
    > new file mode 100644
    > index 0000000..41ab78f
    > --- /dev/null
    > +++ b/drivers/rtc/rtc-jz4740.c
    > @@ -0,0 +1,344 @@
    > +/*
    > + *  Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
    > + *             JZ4740 SoC RTC driver
    > + *
    > + *  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.
    > + *
    > + *  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.,
    > + *  675 Mass Ave, Cambridge, MA 02139, USA.
    > + *
    > + */
    > +
    > +#include <linux/kernel.h>
    > +#include <linux/module.h>
    > +#include <linux/platform_device.h>
    > +#include <linux/rtc.h>
    > +#include <linux/slab.h>
    > +#include <linux/spinlock.h>
    > +
    > +#define JZ_REG_RTC_CTRL                0x00
    > +#define JZ_REG_RTC_SEC         0x04
    > +#define JZ_REG_RTC_SEC_ALARM   0x08
    > +#define JZ_REG_RTC_REGULATOR   0x0C
    > +#define JZ_REG_RTC_HIBERNATE   0x20
    > +#define JZ_REG_RTC_SCRATCHPAD  0x34
    > +
    > +#define JZ_RTC_CTRL_WRDY       BIT(7)
    > +#define JZ_RTC_CTRL_1HZ                BIT(6)
    > +#define JZ_RTC_CTRL_1HZ_IRQ    BIT(5)
    > +#define JZ_RTC_CTRL_AF         BIT(4)
    > +#define JZ_RTC_CTRL_AF_IRQ     BIT(3)
    > +#define JZ_RTC_CTRL_AE         BIT(2)
    > +#define JZ_RTC_CTRL_ENABLE     BIT(0)
    > +
    > +struct jz4740_rtc {
    > +       struct resource *mem;
    > +       void __iomem *base;
    > +
    > +       struct rtc_device *rtc;
    > +
    > +       unsigned int irq;
    > +
    > +       spinlock_t lock;
    > +};
    > +
    > +static inline uint32_t jz4740_rtc_reg_read(struct jz4740_rtc *rtc, size_t reg)
    > +{
    > +       return readl(rtc->base + reg);
    > +}
    > +
    > +static inline void jz4740_rtc_wait_write_ready(struct jz4740_rtc *rtc)
    > +{
    > +       uint32_t ctrl;
    > +       do {
    > +               ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
    > +       } while (!(ctrl & JZ_RTC_CTRL_WRDY));
    > +}
    > +
    > +
    > +static inline void jz4740_rtc_reg_write(struct jz4740_rtc *rtc, size_t reg,
    > +                                       uint32_t val)
    > +{
    > +       jz4740_rtc_wait_write_ready(rtc);
    > +       writel(val, rtc->base + reg);
    > +}
    > +
    > +static void jz4740_rtc_ctrl_set_bits(struct jz4740_rtc *rtc, uint32_t mask,
    > +                                       uint32_t val)
    > +{
    > +       unsigned long flags;
    > +       uint32_t ctrl;
    > +
    > +       spin_lock_irqsave(&rtc->lock, flags);
    > +
    > +       ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
    > +
    > +       /* Don't clear interrupt flags by accident */
    > +       ctrl |= JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF;
    > +
    > +       ctrl &= ~mask;
    > +       ctrl |= val;
    > +
    > +       jz4740_rtc_reg_write(rtc, JZ_REG_RTC_CTRL, ctrl);
    > +
    > +       spin_unlock_irqrestore(&rtc->lock, flags);
    > +}
    > +
    > +static inline struct jz4740_rtc *dev_to_rtc(struct device *dev)
    > +{
    > +       return dev_get_drvdata(dev);
    > +}
    > +

    Why do you need to re-implement the 'dev_to_rtc' instead of using
    'platform_get_drvdata' provided by Linux own.'

    > +static int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time)
    > +{
    > +       struct jz4740_rtc *rtc = dev_to_rtc(dev);
    > +       uint32_t secs, secs2;
    > +
    > +       secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
    > +       secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
    > +
    > +       while (secs != secs2) {
    > +               secs = secs2;
    > +               secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
    > +       }
    > +
    > +       rtc_time_to_tm(secs, time);
    > +
    > +       return rtc_valid_tm(time);
    > +}
    > +
    > +static int jz4740_rtc_set_mmss(struct device *dev, unsigned long secs)
    > +{
    > +       struct jz4740_rtc *rtc = dev_to_rtc(dev);
    > +
    > +       if ((uint32_t)secs != secs)
    > +               return -EINVAL;
    > +
    > +       jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, secs);
    > +
    > +       return 0;
    > +}
    > +
    > +static int jz4740_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
    > +{
    > +       struct jz4740_rtc *rtc = dev_to_rtc(dev);
    > +       uint32_t secs, secs2;
    > +       uint32_t ctrl;
    > +
    > +       secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM);
    > +       secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM);
    > +
    > +       while (secs != secs2) {
    > +               secs = secs2;
    > +               secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC_ALARM);
    > +       }
    > +
    > +       ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
    > +
    > +       alrm->enabled = !!(ctrl & JZ_RTC_CTRL_AE);
    > +       alrm->pending = !!(ctrl & JZ_RTC_CTRL_AF);
    > +
    > +       rtc_time_to_tm(secs, &alrm->time);
    > +
    > +       return rtc_valid_tm(&alrm->time);
    > +}
    > +
    > +static int jz4740_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
    > +{
    > +       struct jz4740_rtc *rtc = dev_to_rtc(dev);
    > +       unsigned long secs;
    > +
    > +       rtc_tm_to_time(&alrm->time, &secs);
    > +
    > +       if ((uint32_t)secs != secs)
    > +               return -EINVAL;
    > +
    > +       jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC_ALARM, (uint32_t)secs);
    > +       jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AE,
    > +                                       alrm->enabled ? JZ_RTC_CTRL_AE : 0);
    > +
    > +       return 0;
    > +}
    > +
    > +static int jz4740_rtc_update_irq_enable(struct device *dev, unsigned int enable)
    > +{
    > +       struct jz4740_rtc *rtc = dev_to_rtc(dev);
    > +       jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ_IRQ,
    > +                                       enable ? JZ_RTC_CTRL_1HZ_IRQ : 0);
    > +       return 0;
    > +}
    > +
    > +
    > +static int jz4740_rtc_alarm_irq_enable(struct device *dev, unsigned int enable)
    > +{
    > +       struct jz4740_rtc *rtc = dev_to_rtc(dev);
    > +       jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AF_IRQ,
    > +                                       enable ? JZ_RTC_CTRL_AF_IRQ : 0);
    > +       return 0;
    > +}
    > +
    > +static struct rtc_class_ops jz4740_rtc_ops = {
    > +       .read_time      = jz4740_rtc_read_time,
    > +       .set_mmss       = jz4740_rtc_set_mmss,
    > +       .read_alarm     = jz4740_rtc_read_alarm,
    > +       .set_alarm      = jz4740_rtc_set_alarm,
    > +       .update_irq_enable = jz4740_rtc_update_irq_enable,
    > +       .alarm_irq_enable = jz4740_rtc_alarm_irq_enable,
    > +};
    > +
    > +static irqreturn_t jz4740_rtc_irq(int irq, void *data)
    > +{
    > +       struct jz4740_rtc *rtc = data;
    > +       uint32_t ctrl;
    > +       unsigned long events = 0;
    > +       ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
    > +
    > +       if (ctrl & JZ_RTC_CTRL_1HZ)
    > +               events |= (RTC_UF | RTC_IRQF);
    > +
    > +       if (ctrl & JZ_RTC_CTRL_AF)
    > +               events |= (RTC_AF | RTC_IRQF);
    > +
    > +       rtc_update_irq(rtc->rtc, 1, events);
    > +
    > +       jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_1HZ | JZ_RTC_CTRL_AF, 0);
    > +
    > +       return IRQ_HANDLED;
    > +}
    > +
    > +void jz4740_rtc_poweroff(struct device *dev)
    > +{
    > +       struct jz4740_rtc *rtc = dev_get_drvdata(dev);
    > +       jz4740_rtc_reg_write(rtc, JZ_REG_RTC_HIBERNATE, 1);
    > +}
    > +EXPORT_SYMBOL_GPL(jz4740_rtc_poweroff);
    > +
    > +static int __devinit jz4740_rtc_probe(struct platform_device *pdev)
    > +{
    > +       int ret;
    > +       struct jz4740_rtc *rtc;
    > +       uint32_t scratchpad;
    > +
    > +       rtc = kmalloc(sizeof(*rtc), GFP_KERNEL);
    > +
    > +       rtc->irq = platform_get_irq(pdev, 0);
    > +
    > +       if (rtc->irq < 0) {
    > +               ret = -ENOENT;
    > +               dev_err(&pdev->dev, "Failed to get platform irq\n");
    > +               goto err_free;
    > +       }
    > +
    > +       rtc->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    > +       if (!rtc->mem) {
    > +               ret = -ENOENT;
    > +               dev_err(&pdev->dev, "Failed to get platform mmio memory\n");
    > +               goto err_free;
    > +       }
    > +
    > +       rtc->mem = request_mem_region(rtc->mem->start, resource_size(rtc->mem),
    > +                                       pdev->name);
    > +
    > +       if (!rtc->mem) {
    > +               ret = -EBUSY;
    > +               dev_err(&pdev->dev, "Failed to request mmio memory region\n");
    > +               goto err_free;
    > +       }
    > +
    > +       rtc->base = ioremap_nocache(rtc->mem->start, resource_size(rtc->mem));
    > +
    > +       if (!rtc->base) {
    > +               ret = -EBUSY;
    > +               dev_err(&pdev->dev, "Failed to ioremap mmio memory\n");
    > +               goto err_release_mem_region;
    > +       }
    > +
    > +       spin_lock_init(&rtc->lock);
    > +
    > +       platform_set_drvdata(pdev, rtc);
    > +
    > +       rtc->rtc = rtc_device_register(pdev->name, &pdev->dev, &jz4740_rtc_ops,
    > +                                       THIS_MODULE);
    > +
    > +       if (IS_ERR(rtc->rtc)) {
    > +               ret = PTR_ERR(rtc->rtc);
    > +               dev_err(&pdev->dev, "Failed to register rtc device: %d\n", ret);
    > +               goto err_iounmap;
    > +       }
    > +
    > +       ret = request_irq(rtc->irq, jz4740_rtc_irq, 0,
    > +                               pdev->name, rtc);
    > +
    > +       if (ret) {
    > +               dev_err(&pdev->dev, "Failed to request rtc irq: %d\n", ret);
    > +               goto err_unregister_rtc;
    > +       }
    > +
    > +       scratchpad = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SCRATCHPAD);
    > +       if (scratchpad != 0x12345678) {
    > +               jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SCRATCHPAD, 0x12345678);
    > +               jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC, 0);
    > +       }
    > +
    > +       return 0;
    > +
    > +err_unregister_rtc:
    > +       rtc_device_unregister(rtc->rtc);
    > +err_iounmap:
    > +       platform_set_drvdata(pdev, NULL);
    > +       iounmap(rtc->base);
    > +err_release_mem_region:
    > +       release_mem_region(rtc->mem->start, resource_size(rtc->mem));
    > +err_free:
    > +       kfree(rtc);
    > +
    > +       return ret;
    > +}
    > +
    > +static int __devexit jz4740_rtc_remove(struct platform_device *pdev)
    > +{
    > +       struct jz4740_rtc *rtc = platform_get_drvdata(pdev);
    > +
    > +       free_irq(rtc->irq, rtc);
    > +
    > +       rtc_device_unregister(rtc->rtc);
    > +
    > +       iounmap(rtc->base);
    > +       release_mem_region(rtc->mem->start, resource_size(rtc->mem));
    > +
    > +       kfree(rtc);
    > +
    > +       platform_set_drvdata(pdev, NULL);
    > +
    > +       return 0;
    > +}
    > +
    > +struct platform_driver jz4740_rtc_driver = {
    > +       .probe = jz4740_rtc_probe,
    > +       .remove = __devexit_p(jz4740_rtc_remove),
    > +       .driver = {
    > +               .name = "jz4740-rtc",
    > +               .owner = THIS_MODULE,
    > +       },
    > +};
    > +
    > +static int __init jz4740_rtc_init(void)
    > +{
    > +       return platform_driver_register(&jz4740_rtc_driver);

    platform_driver_probe is much better here.

    > +}
    > +module_init(jz4740_rtc_init);
    > +
    > +static void __exit jz4740_rtc_exit(void)
    > +{
    > +       platform_driver_unregister(&jz4740_rtc_driver);
    > +}
    > +module_exit(jz4740_rtc_exit);
    > +
    > +MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
    > +MODULE_LICENSE("GPL");
    > +MODULE_DESCRIPTION("RTC driver for the JZ4740 SoC\n");
    > +MODULE_ALIAS("platform:jz4740-rtc");
    > --
    > 1.5.6.5
    >
    > --
    > You received this message because you are subscribed to "rtc-linux".
    > Membership options at http://groups.google.com/group/rtc-linux .
    > Please read http://groups.google.com/group/rtc-linux/web/checklist
    > before submitting a driver.



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