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SubjectRe: [PATCH v3 3/6] rtc: mxc: use a second rtc clock
Hi,

On 20/06/2015 at 19:12:37 +0200, Philippe Reynes wrote :
> - rate = clk_get_rate(pdata->clk);
> + pdata->clk_rtc = devm_clk_get(&pdev->dev, "rtc");
> + if (IS_ERR(pdata->clk_rtc)) {
> + dev_err(&pdev->dev, "unable to get rtc clock!\n");
> + ret = PTR_ERR(pdata->clk_rtc);
> + goto exit_put_clk;
> + }
> +
> + rate = clk_get_rate(pdata->clk_rtc);
>

You have to prepare_enable() before using get_rate(). Else, it is not
guaranteed to work:
"clk_get_rate - obtain the current clock rate (in Hz) for a clock source.
This is only valid once the clock source has been enabled."
http://lxr.free-electrons.com/source/include/linux/clk.h#L269

It may work right now because the clock is enabled elsewhere. But that
may change at some point in time (we had the issue on at91).


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


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