RTC: Add JZ4740 RTC driver
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From: Wan ZongShun on 19 Jun 2010 10:40 2010/6/19 Lars-Peter Clausen <lars(a)metafoo.de>: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Wan ZongShun wrote: >> Hi Lars-Peter, >> >> >>> Hi >>> >>> Marek Vasut wrote: >>>> 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(a)metafoo.de> >>>>> Cc: Alessandro Zummo <a.zummo(a)towertech.it> >>>>> Cc: Paul Gortmaker <p_gortmaker(a)yahoo.com> >>>>> Cc: Wan ZongShun <mcuos.com(a)gmail.com> >>>>> Cc: Marek Vasut <marek.vasut(a)gmail.com> >>>>> Cc: rtc-linux(a)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(a)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() ? >>>> } >>>> >>> Well IF it will ever die, you'll notice cause your rtc clock won't >>> work >>> anymore. >>> >>> It could be wrapped into reg_write, but there is a different >>> version of >>> the SoC with the only difference of the RTC unit being that a >>> different >>> mechanism is used determine whether it is ok to write or not. So it >>> makes sense to keep it seperate. >>>>> +} >>>>> + >>>>> +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() ? >>>> >>> Why would that be preferable? In the non-debug, non-rt case this will >>> expand to local_irq_{save,restore} anyway, but you'll lose the >>> semantics >>> of an lock. >> >> Anyway,spin_lock_irqsave is most universal and secure lock function, >> it can >> apply to smp or single cpu, it can be ok here. >> >> >>>> >>>>> + >>>>> + 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 ? >>>> >>> Strictly speaking not. >>>> >>>>> + >>>>> + 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 ? >>>> >>>> >>> To quote rtc.h "/* 0 = alarm disabled, 1 = alarm enabled */", so yes. >> >> You are right, but it is not true reason. >> >> Please keep (!!) here, to make sure 'enabled' and 'pending' >> to be '0' or '1' is good habit, since they are 'unsigned char' >> variables. >> >> Thanks! >> >>>>> + 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); >> >> Please use kzalloc or kmalloc plus memset, but you forget to add >> memset, >> I prefer kzalloc, of course, you can use latter. >> > All fields of the struct are initialized in probe function, so kzalloc > is unnecessary overhead(small though). Of course, you have the correct reason, but using kzalloc is good habit, now, many people submit their patches to convert kmalloc + memset. In addition, if some guys write their drivers refer to your this driver, but they did not know initializing all the fields of struct is indispensible, which will be a potential dangerous. Other parts of The driver look good to me, except this issue, so I cannot recommend it to Andrew for merging your patch, you have to wait for Andrew's ACK. >>>>> + 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()? >>>> >>>> >>> No. >>>>> + >>>>> + 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); >> In fact, I prefer you can use this IRQ flags, such as IRQF_DISABLED, >> IRQF_SHARED. > IRQF_DISABLED is deprecated and IRQF_SHARED doesn't make any sense > here. In fact not requesting with IRQF_SHARED might help to spot > errors if another driver requested the IRQ by accident (Or this driver > requested the wrong irq). >> >>>>> + 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(a)metafoo.de>"); >>>>> +MODULE_LICENSE("GPL"); >>>>> +MODULE_DESCRIPTION("RTC driver for the JZ4740 SoC\n"); >>>>> +MODULE_ALIAS("platform:jz4740-rtc"); >>>>> >>>> Cheers >>>> > Thanks for reviewing > - - Lars > > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.9 (GNU/Linux) > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org > > iEYEARECAAYFAkwcy80ACgkQBX4mSR26RiM+lgCfZPjAyf1kJstVzqIVlv2uCGMc > ruMAoIRF2fDWMG8mQJFb9V7iTmVTSgqs > =2MQV > -----END PGP SIGNATURE----- > > -- *linux-arm-kernel mailing list mail addr:linux-arm-kernel(a)lists.infradead.org you can subscribe by: http://lists.infradead.org/mailman/listinfo/linux-arm-kernel * linux-arm-NUC900 mailing list mail addr:NUC900(a)googlegroups.com main web: https://groups.google.com/group/NUC900 you can subscribe it by sending me mail: mcuos.com(a)gmail.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Lars-Peter Clausen on 19 Jun 2010 13:50 Marek Vasut wrote: > Dne So 19. června 2010 15:05:18 Lars-Peter Clausen napsal(a): > >> Hi >> >> Marek Vasut wrote: >> >>> 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(a)metafoo.de> >>>> Cc: Alessandro Zummo <a.zummo(a)towertech.it> >>>> Cc: Paul Gortmaker <p_gortmaker(a)yahoo.com> >>>> Cc: Wan ZongShun <mcuos.com(a)gmail.com> >>>> Cc: Marek Vasut <marek.vasut(a)gmail.com> >>>> Cc: rtc-linux(a)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(a)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() ? >>> } >>> >> Well IF it will ever die, you'll notice cause your rtc clock won't work >> anymore. >> > > Then maybe some dev_err() would be good to have there. > That would spam the kernel log. The best solution would be to propagate a -EIO up to rtc_ops callers. But I'm not sure if the overhead is worth it given that the case will virtually never happen. But I'll think about it. >> It could be wrapped into reg_write, but there is a different version of >> the SoC with the only difference of the RTC unit being that a different >> mechanism is used determine whether it is ok to write or not. So it >> makes sense to keep it seperate. >> > > OK > >>>> +} >>>> + >>>> +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() ? >>> >> Why would that be preferable? In the non-debug, non-rt case this will >> expand to local_irq_{save,restore} anyway, but you'll lose the semantics >> of an lock. >> > > I believe on SMP systems, local_irq_save will give you finer locking > granularity. > Hm, not sure about that. But this is on a non SMP system anyway. >>>> + >>>> + 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 ? >>> >> Strictly speaking not. >> > > OK > >>>> + >>>> + 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 ? >>> >> To quote rtc.h "/* 0 = alarm disabled, 1 = alarm enabled */", so yes. >> > > Oh my ... well, maybe someone should fix that to take 0 for NO, !0 for YES. > Well, it's part of the userspace api. >>>> + 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()? >>> >> No. >> > > Why not ? > platform_set_drvdata(pdev, data) expands to dev_set_drvdata(&(pdev)->dev, data) - Lars -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Geert Uytterhoeven on 19 Jun 2010 14:00 On Sat, Jun 19, 2010 at 19:42, Lars-Peter Clausen <lars(a)metafoo.de> wrote: > Marek Vasut wrote: >> Dne So 19. června 2010 15:05:18 Lars-Peter Clausen napsal(a): >>> Marek Vasut wrote: >>>> Dne So 19. června 2010 07:08:20 Lars-Peter Clausen napsal(a): >>>>> This patch adds support for the RTC unit on JZ4740 SoCs. >>>>> +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() ? >>>> >>> Why would that be preferable? In the non-debug, non-rt case this will >>> expand to local_irq_{save,restore} anyway, but you'll lose the semantics >>> of an lock. >>> >> >> I believe on SMP systems, local_irq_save will give you finer locking >> granularity. >> > Hm, not sure about that. But this is on a non SMP system anyway. If the driver will ever be used on a SMP system, local_irq_save() will not protect against concurrent accesses on different CPUs. So it's better to use spin_lock_irqsave(). Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert(a)linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Alessandro Zummo on 22 Jun 2010 02:10
On Sat, 19 Jun 2010 21:29:50 +0200 Lars-Peter Clausen <lars(a)metafoo.de> wrote: > This patch adds support for the RTC unit on JZ4740 SoCs. > > Signed-off-by: Lars-Peter Clausen <lars(a)metafoo.de> > Cc: Alessandro Zummo <a.zummo(a)towertech.it> > Cc: Paul Gortmaker <p_gortmaker(a)yahoo.com> > Cc: rtc-linux(a)googlegroups.com Acked-by: Alessandro Zummo <a.zummo(a)towertech.it> -- Best regards, Alessandro Zummo, Tower Technologies - Torino, Italy http://www.towertech.it -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |