Date:   Mon, 27 May 2019 14:28:14 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     Jon Hunter <jonathanh@...dia.com>,
        Kartik Kartik <kkartik@...dia.com>, linux-rtc@...r.kernel.org,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] rtc: tegra: checkpatch and miscellaneous cleanups

27.05.2019 13:13, Thierry Reding пишет:
> From: Thierry Reding <treding@...dia.com>
> 
> This set of changes fixes some checkpatch warnings as well as a number
> of punctuation and padding inconsistencies.
> 
> Signed-off-by: Thierry Reding <treding@...dia.com>
> ---
>  drivers/rtc/rtc-tegra.c | 154 +++++++++++++++++++++-------------------
>  1 file changed, 79 insertions(+), 75 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-tegra.c b/drivers/rtc/rtc-tegra.c
> index f0ce76865434..a67c9d8be4f6 100644
> --- a/drivers/rtc/rtc-tegra.c
> +++ b/drivers/rtc/rtc-tegra.c
> @@ -18,10 +18,10 @@
>  #include <linux/rtc.h>
>  #include <linux/slab.h>
>  
> -/* set to 1 = busy every eight 32kHz clocks during copy of sec+msec to AHB */
> +/* Set to 1 = busy every eight 32 kHz clocks during copy of sec+msec to AHB. */
>  #define TEGRA_RTC_REG_BUSY			0x004
>  #define TEGRA_RTC_REG_SECONDS			0x008
> -/* when msec is read, the seconds are buffered into shadow seconds. */
> +/* When msec is read, the seconds are buffered into shadow seconds. */
>  #define TEGRA_RTC_REG_SHADOW_SECONDS		0x00c
>  #define TEGRA_RTC_REG_MILLI_SECONDS		0x010
>  #define TEGRA_RTC_REG_SECONDS_ALARM0		0x014
> @@ -46,44 +46,48 @@
>  #define TEGRA_RTC_INTR_STATUS_SEC_ALARM0	(1<<0)
>  
>  struct tegra_rtc_info {
> -	struct platform_device	*pdev;
> -	struct rtc_device	*rtc_dev;
> -	void __iomem		*rtc_base; /* NULL if not initialized. */
> -	struct clk		*clk;
> -	int			tegra_rtc_irq; /* alarm and periodic irq */
> -	spinlock_t		tegra_rtc_lock;
> +	struct platform_device *pdev;
> +	struct rtc_device *rtc_dev;
> +	void __iomem *rtc_base; /* NULL if not initialized */
> +	struct clk *clk;
> +	int tegra_rtc_irq; /* alarm and periodic IRQ */
> +	spinlock_t tegra_rtc_lock;
>  };
>  
> -/* RTC hardware is busy when it is updating its values over AHB once
> - * every eight 32kHz clocks (~250uS).
> - * outside of these updates the CPU is free to write.
> - * CPU is always free to read.
> +/*
> + * RTC hardware is busy when it is updating its values over AHB once every
> + * eight 32 kHz clocks (~250 us). Outside of these updates the CPU is free to
> + * write. CPU is always free to read.
>   */
>  static inline u32 tegra_rtc_check_busy(struct tegra_rtc_info *info)
>  {
>  	return readl(info->rtc_base + TEGRA_RTC_REG_BUSY) & 1;
>  }
>  
> -/* Wait for hardware to be ready for writing.
> - * This function tries to maximize the amount of time before the next update.
> - * It does this by waiting for the RTC to become busy with its periodic update,
> - * then returning once the RTC first becomes not busy.
> +/*
> + * Wait for hardware to be ready for writing. This function tries to maximize
> + * the amount of time before the next update. It does this by waiting for the
> + * RTC to become busy with its periodic update, then returning once the RTC
> + * first becomes not busy.
> + *
>   * This periodic update (where the seconds and milliseconds are copied to the
> - * AHB side) occurs every eight 32kHz clocks (~250uS).
> - * The behavior of this function allows us to make some assumptions without
> - * introducing a race, because 250uS is plenty of time to read/write a value.
> + * AHB side) occurs every eight 32 kHz clocks (~250 us). The behavior of this
> + * function allows us to make some assumptions without introducing a race,
> + * because 250 us is plenty of time to read/write a value.
>   */
>  static int tegra_rtc_wait_while_busy(struct device *dev)
>  {
>  	struct tegra_rtc_info *info = dev_get_drvdata(dev);
> +	int retries = 500; /* ~490 us is the worst case, ~250 us is best */
>  
> -	int retries = 500; /* ~490 us is the worst case, ~250 us is best. */
> -
> -	/* first wait for the RTC to become busy. this is when it
> -	 * posts its updated seconds+msec registers to AHB side. */
> +	/*
> +	 * First wait for the RTC to become busy. This is when it posts its
> +	 * updated seconds+msec registers to AHB side.
> +	 */
>  	while (tegra_rtc_check_busy(info)) {
>  		if (!retries--)
>  			goto retry_failed;
> +
>  		udelay(1);
>  	}
>  
> @@ -91,7 +95,7 @@ static int tegra_rtc_wait_while_busy(struct device *dev)
>  	return 0;
>  
>  retry_failed:
> -	dev_err(dev, "write failed:retry count exceeded.\n");
> +	dev_err(dev, "write failed: retry count exceeded\n");
>  	return -ETIMEDOUT;
>  }
>  
> @@ -101,8 +105,10 @@ static int tegra_rtc_read_time(struct device *dev, struct rtc_time *tm)
>  	unsigned long sec, msec;
>  	unsigned long sl_irq_flags;
>  
> -	/* RTC hardware copies seconds to shadow seconds when a read
> -	 * of milliseconds occurs. use a lock to keep other threads out. */
> +	/*
> +	 * RTC hardware copies seconds to shadow seconds when a read of
> +	 * milliseconds occurs. use a lock to keep other threads out.
> +	 */
>  	spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags);
>  
>  	msec = readl(info->rtc_base + TEGRA_RTC_REG_MILLI_SECONDS);
> @@ -112,7 +118,7 @@ static int tegra_rtc_read_time(struct device *dev, struct rtc_time *tm)
>  
>  	rtc_time64_to_tm(sec, tm);
>  
> -	dev_vdbg(dev, "time read as %lu. %ptR\n", sec, tm);
> +	dev_vdbg(dev, "time read as %u, %ptR\n", sec, tm);
>  
>  	return 0;
>  }
> @@ -123,18 +129,18 @@ static int tegra_rtc_set_time(struct device *dev, struct rtc_time *tm)
>  	unsigned long sec;
>  	int ret;
>  
> -	/* convert tm to seconds. */
> +	/* convert tm to seconds */
>  	sec = rtc_tm_to_time64(tm);
>  
> -	dev_vdbg(dev, "time set to %lu. %ptR\n", sec, tm);
> +	dev_vdbg(dev, "time set to %u, %ptR\n", sec, tm);
>  
> -	/* seconds only written if wait succeeded. */
> +	/* seconds only written if wait succeeded */
>  	ret = tegra_rtc_wait_while_busy(dev);
>  	if (!ret)
>  		writel(sec, info->rtc_base + TEGRA_RTC_REG_SECONDS);
>  
>  	dev_vdbg(dev, "time read back as %d\n",
> -		readl(info->rtc_base + TEGRA_RTC_REG_SECONDS));
> +		 readl(info->rtc_base + TEGRA_RTC_REG_SECONDS));
>  
>  	return ret;
>  }
> @@ -143,15 +149,15 @@ static int tegra_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
>  {
>  	struct tegra_rtc_info *info = dev_get_drvdata(dev);
>  	unsigned long sec;
> -	unsigned tmp;
> +	unsigned int tmp;
>  
>  	sec = readl(info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0);
>  
>  	if (sec == 0) {
> -		/* alarm is disabled. */
> +		/* alarm is disabled */
>  		alarm->enabled = 0;
>  	} else {
> -		/* alarm is enabled. */
> +		/* alarm is enabled */
>  		alarm->enabled = 1;
>  		rtc_time64_to_tm(sec, &alarm->time);
>  	}
> @@ -165,13 +171,13 @@ static int tegra_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alarm)
>  static int tegra_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
>  {
>  	struct tegra_rtc_info *info = dev_get_drvdata(dev);
> -	unsigned status;
>  	unsigned long sl_irq_flags;
> +	unsigned int status;
>  
>  	tegra_rtc_wait_while_busy(dev);
>  	spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags);
>  
> -	/* read the original value, and OR in the flag. */
> +	/* read the original value, and OR in the flag */
>  	status = readl(info->rtc_base + TEGRA_RTC_REG_INTR_MASK);
>  	if (enabled)
>  		status |= TEGRA_RTC_INTR_MASK_SEC_ALARM0; /* set it */
> @@ -198,14 +204,14 @@ static int tegra_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
>  	tegra_rtc_wait_while_busy(dev);
>  	writel(sec, info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0);
>  	dev_vdbg(dev, "alarm read back as %d\n",
> -		readl(info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0));
> +		 readl(info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0));
>  
>  	/* if successfully written and alarm is enabled ... */
>  	if (sec) {
>  		tegra_rtc_alarm_irq_enable(dev, 1);
> -		dev_vdbg(dev, "alarm set as %lu. %ptR\n", sec, &alarm->time);
> +		dev_vdbg(dev, "alarm set as %u, %ptR\n", sec, &alarm->time);
>  	} else {
> -		/* disable alarm if 0 or write error. */
> +		/* disable alarm if 0 or write error */
>  		dev_vdbg(dev, "alarm disabled\n");
>  		tegra_rtc_alarm_irq_enable(dev, 0);
>  	}
> @@ -228,25 +234,26 @@ static irqreturn_t tegra_rtc_irq_handler(int irq, void *data)
>  	struct device *dev = data;
>  	struct tegra_rtc_info *info = dev_get_drvdata(dev);
>  	unsigned long events = 0;
> -	unsigned status;
>  	unsigned long sl_irq_flags;
> +	unsigned int status;
>  
>  	status = readl(info->rtc_base + TEGRA_RTC_REG_INTR_STATUS);
>  	if (status) {
> -		/* clear the interrupt masks and status on any irq. */
> +		/* clear the interrupt masks and status on any IRQ */
>  		tegra_rtc_wait_while_busy(dev);
> +
>  		spin_lock_irqsave(&info->tegra_rtc_lock, sl_irq_flags);
>  		writel(0, info->rtc_base + TEGRA_RTC_REG_INTR_MASK);
>  		writel(status, info->rtc_base + TEGRA_RTC_REG_INTR_STATUS);
>  		spin_unlock_irqrestore(&info->tegra_rtc_lock, sl_irq_flags);
>  	}
>  
> -	/* check if Alarm */
> -	if ((status & TEGRA_RTC_INTR_STATUS_SEC_ALARM0))
> +	/* check if alarm */
> +	if (status & TEGRA_RTC_INTR_STATUS_SEC_ALARM0)
>  		events |= RTC_IRQF | RTC_AF;
>  
> -	/* check if Periodic */
> -	if ((status & TEGRA_RTC_INTR_STATUS_SEC_CDN_ALARM))
> +	/* check if periodic */
> +	if (status & TEGRA_RTC_INTR_STATUS_SEC_CDN_ALARM)
>  		events |= RTC_IRQF | RTC_PF;
>  
>  	rtc_update_irq(info->rtc_dev, 1, events);
> @@ -255,11 +262,11 @@ static irqreturn_t tegra_rtc_irq_handler(int irq, void *data)
>  }
>  
>  static const struct rtc_class_ops tegra_rtc_ops = {
> -	.read_time	= tegra_rtc_read_time,
> -	.set_time	= tegra_rtc_set_time,
> -	.read_alarm	= tegra_rtc_read_alarm,
> -	.set_alarm	= tegra_rtc_set_alarm,
> -	.proc		= tegra_rtc_proc,
> +	.read_time = tegra_rtc_read_time,
> +	.set_time = tegra_rtc_set_time,
> +	.read_alarm = tegra_rtc_read_alarm,
> +	.set_alarm = tegra_rtc_set_alarm,
> +	.proc = tegra_rtc_proc,
>  	.alarm_irq_enable = tegra_rtc_alarm_irq_enable,
>  };
>  
> @@ -275,8 +282,7 @@ static int __init tegra_rtc_probe(struct platform_device *pdev)
>  	struct resource *res;
>  	int ret;
>  
> -	info = devm_kzalloc(&pdev->dev, sizeof(struct tegra_rtc_info),
> -		GFP_KERNEL);
> +	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
>  	if (!info)
>  		return -ENOMEM;
>  
> @@ -308,13 +314,13 @@ static int __init tegra_rtc_probe(struct platform_device *pdev)
>  	if (ret < 0)
>  		return ret;
>  
> -	/* set context info. */
> +	/* set context info */
>  	info->pdev = pdev;
>  	spin_lock_init(&info->tegra_rtc_lock);
>  
>  	platform_set_drvdata(pdev, info);
>  
> -	/* clear out the hardware. */
> +	/* clear out the hardware */
>  	writel(0, info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0);
>  	writel(0xffffffff, info->rtc_base + TEGRA_RTC_REG_INTR_STATUS);
>  	writel(0, info->rtc_base + TEGRA_RTC_REG_INTR_MASK);
> @@ -322,19 +328,16 @@ static int __init tegra_rtc_probe(struct platform_device *pdev)
>  	device_init_wakeup(&pdev->dev, 1);
>  
>  	ret = devm_request_irq(&pdev->dev, info->tegra_rtc_irq,
> -			tegra_rtc_irq_handler, IRQF_TRIGGER_HIGH,
> -			dev_name(&pdev->dev), &pdev->dev);
> +			       tegra_rtc_irq_handler, IRQF_TRIGGER_HIGH,
> +			       dev_name(&pdev->dev), &pdev->dev);
>  	if (ret) {
> -		dev_err(&pdev->dev,
> -			"Unable to request interrupt for device (err=%d).\n",
> -			ret);
> +		dev_err(&pdev->dev, "failed to request interrupt: %d\n", ret);
>  		goto disable_clk;
>  	}
>  
>  	ret = rtc_register_device(info->rtc_dev);
>  	if (ret) {
> -		dev_err(&pdev->dev, "Unable to register device (err=%d).\n",
> -			ret);
> +		dev_err(&pdev->dev, "failed to register device: %d\n", ret);
>  		goto disable_clk;
>  	}
>  
> @@ -363,18 +366,18 @@ static int tegra_rtc_suspend(struct device *dev)
>  
>  	tegra_rtc_wait_while_busy(dev);
>  
> -	/* only use ALARM0 as a wake source. */
> +	/* only use ALARM0 as a wake source */
>  	writel(0xffffffff, info->rtc_base + TEGRA_RTC_REG_INTR_STATUS);
>  	writel(TEGRA_RTC_INTR_STATUS_SEC_ALARM0,
>  		info->rtc_base + TEGRA_RTC_REG_INTR_MASK);
>  
>  	dev_vdbg(dev, "alarm sec = %d\n",
> -		readl(info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0));
> +		 readl(info->rtc_base + TEGRA_RTC_REG_SECONDS_ALARM0));
>  
> -	dev_vdbg(dev, "Suspend (device_may_wakeup=%d) irq:%d\n",
> -		device_may_wakeup(dev), info->tegra_rtc_irq);
> +	dev_vdbg(dev, "Suspend (device_may_wakeup=%d) IRQ:%d\n",
> +		 device_may_wakeup(dev), info->tegra_rtc_irq);
>  
> -	/* leave the alarms on as a wake source. */
> +	/* leave the alarms on as a wake source */
>  	if (device_may_wakeup(dev))
>  		enable_irq_wake(info->tegra_rtc_irq);
>  
> @@ -386,8 +389,9 @@ static int tegra_rtc_resume(struct device *dev)
>  	struct tegra_rtc_info *info = dev_get_drvdata(dev);
>  
>  	dev_vdbg(dev, "Resume (device_may_wakeup=%d)\n",
> -		device_may_wakeup(dev));
> -	/* alarms were left on as a wake source, turn them off. */
> +		 device_may_wakeup(dev));
> +
> +	/* alarms were left on as a wake source, turn them off */
>  	if (device_may_wakeup(dev))
>  		disable_irq_wake(info->tegra_rtc_irq);
>  
> @@ -399,18 +403,17 @@ static SIMPLE_DEV_PM_OPS(tegra_rtc_pm_ops, tegra_rtc_suspend, tegra_rtc_resume);
>  
>  static void tegra_rtc_shutdown(struct platform_device *pdev)
>  {
> -	dev_vdbg(&pdev->dev, "disabling interrupts.\n");
> +	dev_vdbg(&pdev->dev, "disabling interrupts\n");
>  	tegra_rtc_alarm_irq_enable(&pdev->dev, 0);
>  }
>  
> -MODULE_ALIAS("platform:tegra_rtc");
>  static struct platform_driver tegra_rtc_driver = {
> -	.remove		= tegra_rtc_remove,
> -	.shutdown	= tegra_rtc_shutdown,
> -	.driver		= {
> -		.name	= "tegra_rtc",
> +	.remove = tegra_rtc_remove,
> +	.shutdown = tegra_rtc_shutdown,
> +	.driver = {
> +		.name = "tegra_rtc",
>  		.of_match_table = tegra_rtc_dt_match,
> -		.pm	= &tegra_rtc_pm_ops,
> +		.pm = &tegra_rtc_pm_ops,
>  	},
>  };
>  
> @@ -418,4 +421,5 @@ module_platform_driver_probe(tegra_rtc_driver, tegra_rtc_probe);
>  
>  MODULE_AUTHOR("Jon Mayo <jmayo@...dia.com>");
>  MODULE_DESCRIPTION("driver for Tegra internal RTC");
> +MODULE_ALIAS("platform:tegra_rtc");
>  MODULE_LICENSE("GPL");
> 

You could drop MODULE_ALIAS entirely since this is an OF-driver and
hence the modalias is overridden anyway by MODULE_DEVICE_TABLE.

# cat /sys/devices/soc0/7000e000.rtc/modalias
of:NrtcT(null)Cnvidia,tegra20-rtc

-- 
Dmitry

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