From mboxrd@z Thu Jan  1 00:00:00 1970
From: arnd@arndb.de (Arnd Bergmann)
Date: Wed, 22 Feb 2012 12:29:17 +0000
Subject: [PATCH 6/7] rtc: sa1100: enable clk support
In-Reply-To: <1329815096-6200-7-git-send-email-haojian.zhuang@marvell.com>
References: <1329815096-6200-1-git-send-email-haojian.zhuang@marvell.com>
 <1329815096-6200-7-git-send-email-haojian.zhuang@marvell.com>
Message-ID: <201202221229.17934.arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tuesday 21 February 2012, Haojian Zhuang wrote:
> @@ -306,6 +308,13 @@ static int sa1100_rtc_probe(struct platform_device *pdev)
>         if (!info)
>                 return -ENOMEM;
>  
> +       info->clk = clk_get(&pdev->dev, NULL);
> +       if (IS_ERR(info->clk)) {
> +               dev_err(&pdev->dev, "failed to find rtc clock source\n");
> +               ret = PTR_ERR(info->clk);
> +               goto err_clk;
> +       }
> +       clk_prepare_enable(info->clk);
>         info->iobase = res->start;
>         info->iosize = resource_size(res);
>         info->irq_1hz = irq_1hz;
> @@ -379,6 +388,9 @@ err_dev:
>         iounmap(info->reg_base);
>  err_map:
>         platform_set_drvdata(pdev, NULL);
> +       clk_disable_unprepare(info->clk);
> +       clk_put(info->clk);
> +err_clk:
>         kfree(info);
>         return ret;

I wonder whether it would be easier to just make the clk handling
conditional here, like

	info->clk = clk_get(&pdev->dev, NULL);
	if (PTR_ERR(info->clk) == -ENOENT)
		info->clk = NULL;
	if (IS_ERR(info->clk)) {
		ret =  PTR_ERR(info->clk);
		goto err_clk;
	}

	if (info->clk)
		clk_prepare_enable(info->clk);
	...
	if (info->clk) {
		clk_disable_unprepare(info->clk);
		clk_put(info->clk);
	}
		
With this, you would no longer need to add dummy clocks in platforms
that really have no clock handling.

	Arnd