[ 3.5.y.z extended stable ] Patch "rtc: rtc-mv: Add support for clk to avoid lockups" has been added to staging queue

[Jason Cooper]

Luis,

On Wed, Mar 13, 2013 at 01:07:47PM +0000, Luis Henriques wrote:
> This is a note to let you know that I have just added a patch titled
> 
>     rtc: rtc-mv: Add support for clk to avoid lockups
> 
> to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
> which can be found at:
> 
>  http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue
> 
> If you, or anyone else, feels it should not be added to this tree, please 
> reply to this email.
> 
> For more information about the 3.5.y.z tree, see
> https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
> 
> Thanks.
> -Luis
> 
> ------
> 
> From 9630368a7116e76efad66622f6d22758b301e8fc Mon Sep 17 00:00:00 2001
> From: Andrew Lunn <andrew at lunn.ch>
> Date: Sun, 3 Feb 2013 12:32:06 +0100
> Subject: [PATCH] rtc: rtc-mv: Add support for clk to avoid lockups
> 
> commit 89c58c198b252f2bc20657fdd72a2aea788c435c upstream.
> 
> The Marvell RTC on Kirkwood makes use of the runit clock. Ensure the
> driver clk_prepare_enable() this clock, otherwise there is a danger
> the SoC will lockup when accessing RTC registers with the clock
> disabled.
> 
> Reported-by: Simon Baatz <gmbnomis at gmail.com>
> Signed-off-by: Andrew Lunn <andrew at lunn.ch>
> Tested-by: Simon Baatz <gmbnomis at gmail.com>
> Signed-off-by: Jason Cooper <jason at lakedaemon.net>
> Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
> ---
>  arch/arm/boot/dts/kirkwood.dtsi |  1 +
>  drivers/rtc/rtc-mv.c            | 28 ++++++++++++++++++++++++----
>  2 files changed, 25 insertions(+), 4 deletions(-)

Please drop this patch from the v3.5.x queue.  The Marvell SoCs hadn't
converted over to common clock yet.  At best this patch is a no-op, at
worst, it breaks the kirkwood.dtsi (there is no label &gate_clk yet).

thx,

Jason.

> 
> diff --git a/arch/arm/boot/dts/kirkwood.dtsi b/arch/arm/boot/dts/kirkwood.dtsi
> index 926528b..1c2e72c 100644
> --- a/arch/arm/boot/dts/kirkwood.dtsi
> +++ b/arch/arm/boot/dts/kirkwood.dtsi
> @@ -31,6 +31,7 @@
>  			compatible = "mrvl,kirkwood-rtc", "mrvl,orion-rtc";
>  			reg = <0x10300 0x20>;
>  			interrupts = <53>;
> +			clocks = <&gate_clk 7>;
>  		};
> 
>  		nand at 3000000 {
> diff --git a/drivers/rtc/rtc-mv.c b/drivers/rtc/rtc-mv.c
> index b2185f4..39b213e 100644
> --- a/drivers/rtc/rtc-mv.c
> +++ b/drivers/rtc/rtc-mv.c
> @@ -14,6 +14,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/of.h>
>  #include <linux/delay.h>
> +#include <linux/clk.h>
>  #include <linux/gfp.h>
>  #include <linux/module.h>
> 
> @@ -41,6 +42,7 @@ struct rtc_plat_data {
>  	struct rtc_device *rtc;
>  	void __iomem *ioaddr;
>  	int		irq;
> +	struct clk	*clk;
>  };
> 
>  static int mv_rtc_set_time(struct device *dev, struct rtc_time *tm)
> @@ -221,6 +223,7 @@ static int __devinit mv_rtc_probe(struct platform_device *pdev)
>  	struct rtc_plat_data *pdata;
>  	resource_size_t size;
>  	u32 rtc_time;
> +	int ret = 0;
> 
>  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	if (!res)
> @@ -239,11 +242,17 @@ static int __devinit mv_rtc_probe(struct platform_device *pdev)
>  	if (!pdata->ioaddr)
>  		return -ENOMEM;
> 
> +	pdata->clk = devm_clk_get(&pdev->dev, NULL);
> +	/* Not all SoCs require a clock.*/
> +	if (!IS_ERR(pdata->clk))
> +		clk_prepare_enable(pdata->clk);
> +
>  	/* make sure the 24 hours mode is enabled */
>  	rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
>  	if (rtc_time & RTC_HOURS_12H_MODE) {
>  		dev_err(&pdev->dev, "24 Hours mode not supported.\n");
> -		return -EINVAL;
> +		ret = -EINVAL;
> +		goto out;
>  	}
> 
>  	/* make sure it is actually functional */
> @@ -252,7 +261,8 @@ static int __devinit mv_rtc_probe(struct platform_device *pdev)
>  		rtc_time = readl(pdata->ioaddr + RTC_TIME_REG_OFFS);
>  		if (rtc_time == 0x01000000) {
>  			dev_err(&pdev->dev, "internal RTC not ticking\n");
> -			return -ENODEV;
> +			ret = -ENODEV;
> +			goto out;
>  		}
>  	}
> 
> @@ -268,8 +278,10 @@ static int __devinit mv_rtc_probe(struct platform_device *pdev)
>  	} else
>  		pdata->rtc = rtc_device_register(pdev->name, &pdev->dev,
>  						 &mv_rtc_ops, THIS_MODULE);
> -	if (IS_ERR(pdata->rtc))
> -		return PTR_ERR(pdata->rtc);
> +	if (IS_ERR(pdata->rtc)) {
> +		ret = PTR_ERR(pdata->rtc);
> +		goto out;
> +	}
> 
>  	if (pdata->irq >= 0) {
>  		writel(0, pdata->ioaddr + RTC_ALARM_INTERRUPT_MASK_REG_OFFS);
> @@ -282,6 +294,11 @@ static int __devinit mv_rtc_probe(struct platform_device *pdev)
>  	}
> 
>  	return 0;
> +out:
> +	if (!IS_ERR(pdata->clk))
> +		clk_disable_unprepare(pdata->clk);
> +
> +	return ret;
>  }
> 
>  static int __exit mv_rtc_remove(struct platform_device *pdev)
> @@ -292,6 +309,9 @@ static int __exit mv_rtc_remove(struct platform_device *pdev)
>  		device_init_wakeup(&pdev->dev, 0);
> 
>  	rtc_device_unregister(pdata->rtc);
> +	if (!IS_ERR(pdata->clk))
> +		clk_disable_unprepare(pdata->clk);
> +
>  	return 0;
>  }
> 
> --
> 1.8.1.2
>