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    SubjectRe: [PATCH v2 15/26] RTC: Add JZ4740 RTC driver
    Date
    Dne So 19. června 2010 07:08:20 Lars-Peter Clausen napsal(a):
    > 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: Wan ZongShun <mcuos.com@gmail.com>
    > Cc: Marek Vasut <marek.vasut@gmail.com>
    > Cc: rtc-linux@googlegroups.com
    >
    > ---
    > Changes since v1
    > - Use dev_get_drvdata directly instead of wrapping it in dev_to_rtc
    > - Add common implementation for jz4740_rtc_{alarm,update}_irq_enable
    > - Check whether rtc structure could be allocated
    > - Fix deadlocks which could occur if the HW was broken
    > ---
    > drivers/rtc/Kconfig | 11 ++
    > drivers/rtc/Makefile | 1 +
    > drivers/rtc/rtc-jz4740.c | 341
    > ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 353
    > 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..720afb2
    > --- /dev/null
    > +++ b/drivers/rtc/rtc-jz4740.c
    > @@ -0,0 +1,341 @@
    > +/*
    > + * 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;
    > + int timeout = 1000;
    > +
    > + do {
    > + ctrl = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_CTRL);
    > + } while (!(ctrl & JZ_RTC_CTRL_WRDY) && --timeout);

    if (!timeout) {
    scream_and_die_in_pain();
    dev_err("I died");
    ... or something like that ... what if it times out, in this implementation,
    noone will know this failed.

    I haven't looked through the whole source code, but can't this be wrapped into
    the reg_write() ?
    }
    > +}
    > +
    > +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);

    Can't we use local_irq_save()/local_irq_restore() ?

    > +
    > + 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 int jz4740_rtc_read_time(struct device *dev, struct rtc_time *time)
    > +{
    > + struct jz4740_rtc *rtc = dev_get_drvdata(dev);
    > + uint32_t secs, secs2;
    > + int timeout = 5;
    > +
    > + /* If the seconds register is read while it is updated, it can contain a
    > + * bogus value. This can be avoided by making sure that two consecutive
    > + * reads have the same value.
    > + */
    > + secs = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
    > + secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
    > +
    > + while (secs != secs2 && --timeout) {
    > + secs = secs2;
    > + secs2 = jz4740_rtc_reg_read(rtc, JZ_REG_RTC_SEC);
    > + }
    > +
    > + if (timeout == 0)
    > + return -EIO;
    > +
    > + 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_get_drvdata(dev);
    > +
    > + if ((uint32_t)secs != secs)
    > + return -EINVAL;

    Is the typecast here necessary ?

    > +
    > + 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_get_drvdata(dev);
    > + uint32_t secs;
    > + uint32_t ctrl;
    > +
    > + secs = 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);
    > +

    Is the double negation (!!) here necessary ?

    > + 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_get_drvdata(dev);
    > + unsigned long secs;
    > +
    > + rtc_tm_to_time(&alrm->time, &secs);
    > +
    > + if ((uint32_t)secs != secs)
    > + return -EINVAL;

    DTTO above

    > +
    > + jz4740_rtc_reg_write(rtc, JZ_REG_RTC_SEC_ALARM, (uint32_t)secs);

    DTTO

    > + jz4740_rtc_ctrl_set_bits(rtc, JZ_RTC_CTRL_AE,
    > + alrm->enabled ? JZ_RTC_CTRL_AE : 0);

    Possibly the double negation above wasn't necessary

    > +
    > + return 0;
    > +}
    > +
    > +static inline int jz4740_irq_enable(struct device *dev, int irq,
    > + unsigned int enable)
    > +{
    > + struct jz4740_rtc *rtc = dev_get_drvdata(dev);
    > + jz4740_rtc_ctrl_set_bits(rtc, irq, enable ? irq : 0);
    > +
    > + return 0;
    > +}
    > +
    > +static int jz4740_rtc_update_irq_enable(struct device *dev, unsigned int
    > enable) +{
    > + return jz4740_irq_enable(dev, JZ_RTC_CTRL_1HZ_IRQ, enable);
    > +}
    > +
    > +static int jz4740_rtc_alarm_irq_enable(struct device *dev, unsigned int
    > enable) +{
    > + return jz4740_irq_enable(dev, JZ_RTC_CTRL_AF_IRQ, enable);
    > +}
    > +
    > +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);
    > + if (!rtc)
    > + return -ENOMEM;
    > +
    > + 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);

    dev_set_drvdata()?

    > +
    > + 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);

    dev_get_drvdata();

    > +
    > + 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);

    DTTO

    > +
    > + 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);
    > +}
    > +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");

    Cheers
    --
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      Last update: 2010-06-19 12:49    [W:0.049 / U:30.484 seconds]
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