linux-kernel - Re: [PATCH] rtc: zynqmp: Disable the build as a module

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Date:   Mon, 21 Aug 2017 10:46:41 +0200
From:   Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:     Michal Simek <michal.simek@...inx.com>
Cc:     linux-kernel@...r.kernel.org, monstr@...str.eu,
        Sören Brinkmann <soren.brinkmann@...inx.com>,
        linux-rtc@...r.kernel.org, Alessandro Zummo <a.zummo@...ertech.it>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] rtc: zynqmp: Disable the build as a module

Hi,

As discussed, I will not apply that patch and instead will push for:
https://patchwork.kernel.org/patch/9911471/

On 19/07/2017 at 13:39:57 +0200, Michal Simek wrote:
> The patch:
> "timers: Introduce in-kernel alarm-timer interface"
> (sha1: ff3ead96d17f47ee70c294a5cc2cce9b61e82f0f)
> introduced new requirement that RTC drivers with alarm functionality
> can't be used as a module.
> When module is unloaded there is still a reference that's why
> rtc_device_release() is not called and ida is not freed.
> 
> That's why when module is loaded again it can't use the same RTC number
> based on aliases.
> 
> Log:
> sh-4.3# modprobe rtc-zynqmp
> [   42.468565] rtc_zynqmp ffa60000.rtc: rtc core: registered
> ffa60000.rtc as rtc5
> sh-4.3# rmmod rtc-zynqmp
> sh-4.3# modprobe rtc-zynqmp
> [   48.648222] rtc_zynqmp ffa60000.rtc: /aliases ID 5 not available
> [   48.654280] rtc_zynqmp ffa60000.rtc: rtc core: registered
> ffa60000.rtc as rtc0
> 
> This patch is removing module support which is just a workaround till
> alarm-timer interface is fixed to support device releasing when alarm
> timer is not used.
> 
> Signed-off-by: Michal Simek <michal.simek@...inx.com>
> ---
> 
> Based on discussion:
> https://www.mail-archive.com/rtc-linux@googlegroups.com/msg00908.html
> 
> ---
>  drivers/rtc/Kconfig      |  2 +-
>  drivers/rtc/rtc-zynqmp.c | 15 +--------------
>  2 files changed, 2 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
> index 72419ac2c52a..a2bbe7c2cf92 100644
> --- a/drivers/rtc/Kconfig
> +++ b/drivers/rtc/Kconfig
> @@ -1225,7 +1225,7 @@ config RTC_DRV_OPAL
>  	  will be called rtc-opal.
>  
>  config RTC_DRV_ZYNQMP
> -	tristate "Xilinx Zynq Ultrascale+ MPSoC RTC"
> +	bool "Xilinx Zynq Ultrascale+ MPSoC RTC"
>  	depends on OF
>  	help
>  	  If you say yes here you get support for the RTC controller found on
> diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c
> index da18a8ae3c1d..5fc50145dbd2 100644
> --- a/drivers/rtc/rtc-zynqmp.c
> +++ b/drivers/rtc/rtc-zynqmp.c
> @@ -268,14 +268,6 @@ static int xlnx_rtc_probe(struct platform_device *pdev)
>  	return PTR_ERR_OR_ZERO(xrtcdev->rtc);
>  }
>  
> -static int xlnx_rtc_remove(struct platform_device *pdev)
> -{
> -	xlnx_rtc_alarm_irq_enable(&pdev->dev, 0);
> -	device_init_wakeup(&pdev->dev, 0);
> -
> -	return 0;
> -}
> -
>  static int __maybe_unused xlnx_rtc_suspend(struct device *dev)
>  {
>  	struct platform_device *pdev = to_platform_device(dev);
> @@ -312,7 +304,6 @@ static int __maybe_unused xlnx_rtc_resume(struct device *dev)
>  
>  static struct platform_driver xlnx_rtc_driver = {
>  	.probe		= xlnx_rtc_probe,
> -	.remove		= xlnx_rtc_remove,
>  	.driver		= {
>  		.name	= KBUILD_MODNAME,
>  		.pm	= &xlnx_rtc_pm_ops,
> @@ -320,8 +311,4 @@ static int __maybe_unused xlnx_rtc_resume(struct device *dev)
>  	},
>  };
>  
> -module_platform_driver(xlnx_rtc_driver);
> -
> -MODULE_DESCRIPTION("Xilinx Zynq MPSoC RTC driver");
> -MODULE_AUTHOR("Xilinx Inc.");
> -MODULE_LICENSE("GPL v2");
> +builtin_platform_driver(xlnx_rtc_driver);
> -- 
> 1.9.1
> 

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com