Re: [rtc-linux] [RFC][PATCH 15/26] RTC: Add JZ4740 RTC driver

Wan ZongShun
2010-06-05T15:48:13Z

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
>
> --
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> 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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