Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756334Ab0FSRnQ (ORCPT ); Sat, 19 Jun 2010 13:43:16 -0400 Received: from mailhost.informatik.uni-hamburg.de ([134.100.9.70]:37292 "EHLO mailhost.informatik.uni-hamburg.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754063Ab0FSRnP (ORCPT ); Sat, 19 Jun 2010 13:43:15 -0400 Message-ID: <4C1D0189.6050803@metafoo.de> Date: Sat, 19 Jun 2010 19:42:33 +0200 From: Lars-Peter Clausen User-Agent: Mozilla-Thunderbird 2.0.0.24 (X11/20100329) MIME-Version: 1.0 To: Marek Vasut CC: Ralf Baechle , linux-mips@linux-mips.org, linux-kernel@vger.kernel.org, Alessandro Zummo , Paul Gortmaker , Wan ZongShun , rtc-linux@googlegroups.com Subject: Re: [PATCH v2 15/26] RTC: Add JZ4740 RTC driver References: <1276924111-11158-1-git-send-email-lars@metafoo.de> <201006191243.39793.marek.vasut@gmail.com> <4C1CC08E.5050009@metafoo.de> <201006191604.25329.marek.vasut@gmail.com> In-Reply-To: <201006191604.25329.marek.vasut@gmail.com> X-Enigmail-Version: 0.95.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 13018 Lines: 428 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 >>>> Cc: Alessandro Zummo >>>> Cc: Paul Gortmaker >>>> Cc: Wan ZongShun >>>> Cc: Marek Vasut >>>> 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 >>>> + * 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 >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> + >>>> +#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@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/