Re: [rtc-linux] [PATCH] rtc: rtc-lpc32xx: Introduce RTC driver for the LPC32XX SoC (v2)

[Wan ZongShun <mcuos.com@gmail.com>]

2010/8/12  <wellsk40@gmail.com>:
> From: Kevin Wells <wellsk40@gmail.com>
>
> This patch contains the RTC driver for the built-in RTC in
> the LPC32XX SoC. This patch includes updates from the initial
> review comments.
>
> Changes since v1:
>        Fixed spaces/tabbing in lpc32xx entry in Kconfig/Makefile
>        Remove improper enable for rtc->alarm_enabled
>        Removed typecast on rtc structure in irq handler
>        Switch to resource managed (devm_) variants of kzalloc
>                and other functions in probe. Updated remove
>                based on these changes.
>        Disabled alarm on probe instead of keeping current register
>                settings. No changes for suspend.
>        Allowed driver to continue operation without wakeup or
>                alarm irq if the rtc irq request failed.
>        Relocated module_init and _exit macros to just after it's
>                associated function
>        Passed a NULL pointer to .driver.pm in platform driver
>                structure instead of a list of NULL functions.
>        Added MODULE_ALIAS
>
> Signed-off-by: Kevin Wells <wellsk40@gmail.com>
> Signed-off-by: Durgesh Pattamatta <durgesh.pattamatta@nxp.com>

Now, it looks good to me.

Acked-by: Wan ZongShun <mcuos.com@gmail.com>

> ---
>  drivers/rtc/Kconfig       |    9 +
>  drivers/rtc/Makefile      |    1 +
>  drivers/rtc/rtc-lpc32xx.c |  392 +++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 402 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/rtc/rtc-lpc32xx.c
>
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 4301a6c..5bfb91e 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -916,4 +916,13 @@ config RTC_DRV_JZ4740
>          This driver can also be buillt as a module. If so, the module
>          will be called rtc-jz4740.
>
> +config RTC_DRV_LPC32XX
> +       depends on ARCH_LPC32XX
> +       tristate "NXP LPC32XX RTC"
> +       help
> +         This enables support for the NXP RTC in the LPC32XX
> +
> +         This driver can also be buillt as a module. If so, the module
> +         will be called rtc-lpc32xx.
> +
>  endif # RTC_CLASS
> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
> index fedf9bb..f90c5ad 100644
> --- a/drivers/rtc/Makefile
> +++ b/drivers/rtc/Makefile
> @@ -48,6 +48,7 @@ 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-$(CONFIG_RTC_DRV_LPC32XX)  += rtc-lpc32xx.o
>  obj-$(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-lpc32xx.c b/drivers/rtc/rtc-lpc32xx.c
> new file mode 100644
> index 0000000..b331742
> --- /dev/null
> +++ b/drivers/rtc/rtc-lpc32xx.c
> @@ -0,0 +1,392 @@
> +/*
> + * Copyright (C) 2010 NXP Semiconductors
> + *
> + * 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/init.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock.h>
> +#include <linux/rtc.h>
> +#include <linux/slab.h>
> +#include <linux/io.h>
> +
> +/*
> + * Clock and Power control register offsets
> + */
> +#define RTC_UCOUNT             0x00
> +#define RTC_DCOUNT             0x04
> +#define RTC_MATCH0             0x08
> +#define RTC_MATCH1             0x0C
> +#define RTC_CTRL               0x10
> +#define RTC_INTSTAT            0x14
> +#define RTC_KEY                        0x18
> +#define RTC_SRAM               0x80
> +
> +#define RTC_MATCH0_EN          (1 << 0)
> +#define RTC_MATCH1_EN          (1 << 1)
> +#define RTC_ONSW_MATCH0_EN     (1 << 2)
> +#define RTC_ONSW_MATCH1_EN     (1 << 3)
> +#define RTC_SW_RESET           (1 << 4)
> +#define RTC_CNTR_DIS           (1 << 6)
> +#define RTC_ONSW_FORCE_HIGH    (1 << 7)
> +
> +#define RTC_MATCH0_INT_STS     (1 << 0)
> +#define RTC_MATCH1_INT_STS     (1 << 1)
> +#define RTC_ONSW_INT_STS       (1 << 2)
> +
> +#define RTC_KEY_ONSW_LOADVAL   0xB5C13F27
> +
> +#define RTC_NAME "rtc-lpc32xx"
> +
> +#define rtc_readl(dev, reg) \
> +       __raw_readl((dev)->rtc_base + (reg))
> +#define rtc_writel(dev, reg, val) \
> +       __raw_writel((val), (dev)->rtc_base + (reg))
> +
> +struct lpc32xx_rtc {
> +       void __iomem *rtc_base;
> +       int irq;
> +       int alarm_enabled;
> +       struct rtc_device *rtc;
> +       spinlock_t lock;
> +};
> +
> +static int lpc32xx_rtc_read_time(struct device *dev, struct rtc_time *time)
> +{
> +       unsigned long elapsed_sec;
> +       struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
> +
> +       elapsed_sec = rtc_readl(rtc, RTC_UCOUNT);
> +       rtc_time_to_tm(elapsed_sec, time);
> +
> +       return rtc_valid_tm(time);
> +}
> +
> +static int lpc32xx_rtc_set_mmss(struct device *dev, unsigned long secs)
> +{
> +       struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
> +       u32 tmp;
> +
> +       spin_lock_irq(&rtc->lock);
> +
> +       /* RTC must be disabled during count update */
> +       tmp = rtc_readl(rtc, RTC_CTRL);
> +       rtc_writel(rtc, RTC_CTRL, tmp | RTC_CNTR_DIS);
> +       rtc_writel(rtc, RTC_UCOUNT, secs);
> +       rtc_writel(rtc, RTC_DCOUNT, 0xFFFFFFFF - secs);
> +       rtc_writel(rtc, RTC_CTRL, tmp &= ~RTC_CNTR_DIS);
> +
> +       spin_unlock_irq(&rtc->lock);
> +
> +       return 0;
> +}
> +
> +static int lpc32xx_rtc_read_alarm(struct device *dev,
> +       struct rtc_wkalrm *wkalrm)
> +{
> +       struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
> +
> +       rtc_time_to_tm(rtc_readl(rtc, RTC_MATCH0), &wkalrm->time);
> +       wkalrm->enabled = rtc->alarm_enabled;
> +
> +       return rtc_valid_tm(&wkalrm->time);
> +}
> +
> +static int lpc32xx_rtc_set_alarm(struct device *dev,
> +       struct rtc_wkalrm *wkalrm)
> +{
> +       struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
> +       unsigned long alarmsecs;
> +       u32 tmp;
> +       int ret;
> +
> +       ret = rtc_tm_to_time(&wkalrm->time, &alarmsecs);
> +       if (ret < 0) {
> +               dev_err(dev, "Failed to convert time: %d\n", ret);
> +               return ret;
> +       }
> +
> +       spin_lock_irq(&rtc->lock);
> +
> +       /* Disable alarm during update */
> +       tmp = rtc_readl(rtc, RTC_CTRL);
> +       rtc_writel(rtc, RTC_CTRL, tmp & ~RTC_MATCH0_EN);
> +
> +       rtc->alarm_enabled = wkalrm->enabled;
> +       if (wkalrm->enabled) {
> +               rtc_writel(rtc, RTC_MATCH0, alarmsecs);
> +               rtc_writel(rtc, RTC_INTSTAT, RTC_MATCH0_INT_STS);
> +               rtc_writel(rtc, RTC_CTRL, tmp | RTC_MATCH0_EN);
> +       }
> +
> +       spin_unlock_irq(&rtc->lock);
> +
> +       return 0;
> +}
> +
> +static int lpc32xx_rtc_alarm_irq_enable(struct device *dev,
> +       unsigned int enabled)
> +{
> +       struct lpc32xx_rtc *rtc = dev_get_drvdata(dev);
> +       u32 tmp;
> +
> +       spin_lock_irq(&rtc->lock);
> +       rtc->alarm_enabled = (int) enabled;
> +       tmp = rtc_readl(rtc, RTC_CTRL);
> +
> +       if (enabled)
> +               tmp |= RTC_MATCH0_EN;
> +       else
> +               tmp &= ~RTC_MATCH0_EN;
> +
> +       rtc_writel(rtc, RTC_CTRL, tmp);
> +       spin_unlock_irq(&rtc->lock);
> +
> +       return 0;
> +}
> +
> +static irqreturn_t lpc32xx_rtc_alarm_interrupt(int irq, void *dev)
> +{
> +       struct lpc32xx_rtc *rtc = dev;
> +
> +       spin_lock(&rtc->lock);
> +
> +       /* Disable alarm interrupt */
> +       rtc_writel(rtc, RTC_CTRL,
> +               rtc_readl(rtc, RTC_CTRL) & ~RTC_MATCH0_EN);
> +       rtc->alarm_enabled = 0;
> +
> +       /*
> +        * Write a large value to the match value so the RTC won't
> +        * keep firing the match status
> +        */
> +       rtc_writel(rtc, RTC_MATCH0, 0xFFFFFFFF);
> +       rtc_writel(rtc, RTC_INTSTAT, RTC_MATCH0_INT_STS);
> +
> +       spin_unlock(&rtc->lock);
> +
> +       rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF);
> +
> +       return IRQ_HANDLED;
> +}
> +
> +static const struct rtc_class_ops lpc32xx_rtc_ops = {
> +       .read_time              = lpc32xx_rtc_read_time,
> +       .set_mmss               = lpc32xx_rtc_set_mmss,
> +       .read_alarm             = lpc32xx_rtc_read_alarm,
> +       .set_alarm              = lpc32xx_rtc_set_alarm,
> +       .alarm_irq_enable       = lpc32xx_rtc_alarm_irq_enable,
> +};
> +
> +static int __devinit lpc32xx_rtc_probe(struct platform_device *pdev)
> +{
> +       struct resource *res;
> +       struct lpc32xx_rtc *rtc;
> +       resource_size_t size;
> +       int rtcirq;
> +       u32 tmp;
> +
> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       if (!res) {
> +               dev_err(&pdev->dev, "Can't get memory resource\n");
> +               return -ENOENT;
> +       }
> +
> +       rtcirq = platform_get_irq(pdev, 0);
> +       if (rtcirq < 0 || rtcirq >= NR_IRQS) {
> +               dev_warn(&pdev->dev, "Can't get interrupt resource\n");
> +               rtcirq = -1;
> +       }
> +
> +       rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
> +       if (unlikely(!rtc)) {
> +               dev_err(&pdev->dev, "Can't allocate memory\n");
> +               return -ENOMEM;
> +       }
> +       rtc->irq = rtcirq;
> +
> +       size = resource_size(res);
> +
> +       if (!devm_request_mem_region(&pdev->dev, res->start, size,
> +                                    pdev->name)) {
> +               dev_err(&pdev->dev, "RTC registers are not free\n");
> +               return -EBUSY;
> +       }
> +
> +       rtc->rtc_base = devm_ioremap(&pdev->dev, res->start, size);
> +       if (!rtc->rtc_base) {
> +               dev_err(&pdev->dev, "Can't map memory\n");
> +               return -ENOMEM;
> +       }
> +
> +       spin_lock_init(&rtc->lock);
> +
> +       /*
> +        * The RTC is on a seperate power domain and can keep it's state
> +        * across a chip power cycle. If the RTC has never been previously
> +        * setup, then set it up now for the first time.
> +        */
> +       tmp = rtc_readl(rtc, RTC_CTRL);
> +       if (rtc_readl(rtc, RTC_KEY) == RTC_KEY_ONSW_LOADVAL) {
> +               tmp &= ~(RTC_SW_RESET | RTC_CNTR_DIS | RTC_MATCH0_EN |
> +                       RTC_MATCH1_EN | RTC_ONSW_MATCH0_EN |
> +                       RTC_ONSW_MATCH1_EN | RTC_ONSW_FORCE_HIGH);
> +               rtc_writel(rtc, RTC_CTRL, tmp);
> +
> +               /* Clear latched interrupt states */
> +               rtc_writel(rtc, RTC_MATCH0, 0xFFFFFFFF);
> +               rtc_writel(rtc, RTC_INTSTAT, RTC_MATCH0_INT_STS |
> +                       RTC_MATCH1_INT_STS | RTC_ONSW_INT_STS);
> +
> +               /* Write key value to RTC so it won't reload on reset */
> +               rtc_writel(rtc, RTC_KEY, RTC_KEY_ONSW_LOADVAL);
> +       } else
> +               rtc_writel(rtc, RTC_CTRL, tmp & ~RTC_ONSW_MATCH0_EN);
> +
> +       platform_set_drvdata(pdev, rtc);
> +
> +       rtc->rtc = rtc_device_register(RTC_NAME, &pdev->dev, &lpc32xx_rtc_ops,
> +               THIS_MODULE);
> +       if (IS_ERR(rtc->rtc)) {
> +               dev_err(&pdev->dev, "Can't get RTC\n");
> +               return PTR_ERR(rtc->rtc);
> +       }
> +
> +       /*
> +        * IRQ is enabled after device registration in case alarm IRQ
> +        * is pending upon suspend exit.
> +        */
> +       if (rtc->irq >= 0) {
> +               if (devm_request_irq(&pdev->dev, rtc->irq,
> +                                    lpc32xx_rtc_alarm_interrupt,
> +                                    IRQF_DISABLED, pdev->name, rtc) < 0) {
> +                       dev_warn(&pdev->dev, "Can't request interrupt.\n");
> +                       rtc->irq = -1;
> +               } else
> +                       device_init_wakeup(&pdev->dev, 1);
> +       }
> +
> +       return 0;
> +}
> +
> +static int __devexit lpc32xx_rtc_remove(struct platform_device *pdev)
> +{
> +       struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
> +
> +       if (rtc->irq >= 0)
> +               device_init_wakeup(&pdev->dev, 0);
> +
> +       rtc_device_unregister(rtc->rtc);
> +
> +       return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int lpc32xx_rtc_suspend(struct device *dev)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
> +
> +       if (rtc->irq >= 0) {
> +               if (device_may_wakeup(&pdev->dev))
> +                       enable_irq_wake(rtc->irq);
> +               else
> +                       disable_irq_wake(rtc->irq);
> +       }
> +
> +       return 0;
> +}
> +
> +static int lpc32xx_rtc_resume(struct device *dev)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
> +
> +       if (rtc->irq >= 0 && device_may_wakeup(&pdev->dev))
> +               disable_irq_wake(rtc->irq);
> +
> +       return 0;
> +}
> +
> +/* Unconditionally disable the alarm */
> +static int lpc32xx_rtc_freeze(struct device *dev)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
> +
> +       spin_lock_irq(&rtc->lock);
> +
> +       rtc_writel(rtc, RTC_CTRL,
> +               rtc_readl(rtc, RTC_CTRL) & ~RTC_MATCH0_EN);
> +
> +       spin_unlock_irq(&rtc->lock);
> +
> +       return 0;
> +}
> +
> +static int lpc32xx_rtc_thaw(struct device *dev)
> +{
> +       struct platform_device *pdev = to_platform_device(dev);
> +       struct lpc32xx_rtc *rtc = platform_get_drvdata(pdev);
> +
> +       if (rtc->alarm_enabled) {
> +               spin_lock_irq(&rtc->lock);
> +
> +               rtc_writel(rtc, RTC_CTRL,
> +                       rtc_readl(rtc, RTC_CTRL) | RTC_MATCH0_EN);
> +
> +               spin_unlock_irq(&rtc->lock);
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct dev_pm_ops lpc32xx_rtc_pm_ops = {
> +       .suspend = lpc32xx_rtc_suspend,
> +       .resume = lpc32xx_rtc_resume,
> +       .freeze = lpc32xx_rtc_freeze,
> +       .thaw = lpc32xx_rtc_thaw,
> +       .restore = lpc32xx_rtc_resume
> +};
> +
> +#define LPC32XX_RTC_PM_OPS (&lpc32xx_rtc_pm_ops)
> +#else
> +#define LPC32XX_RTC_PM_OPS NULL
> +#endif
> +
> +static struct platform_driver lpc32xx_rtc_driver = {
> +       .probe          = lpc32xx_rtc_probe,
> +       .remove         = __devexit_p(lpc32xx_rtc_remove),
> +       .driver = {
> +               .name   = RTC_NAME,
> +               .owner  = THIS_MODULE,
> +               .pm     = LPC32XX_RTC_PM_OPS
> +       },
> +};
> +
> +static int __init lpc32xx_rtc_init(void)
> +{
> +       return platform_driver_register(&lpc32xx_rtc_driver);
> +}
> +module_init(lpc32xx_rtc_init);
> +
> +static void __exit lpc32xx_rtc_exit(void)
> +{
> +       platform_driver_unregister(&lpc32xx_rtc_driver);
> +}
> +module_exit(lpc32xx_rtc_exit);
> +
> +MODULE_AUTHOR("Kevin Wells <wellsk40@gmail.com");
> +MODULE_DESCRIPTION("RTC driver for the LPC32xx SoC");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:rtc-lpc32xx");
> --
> 1.7.1.1
>
> --
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> before submitting a driver.



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