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SubjectRe: [PATCH] clkdev: only fall through to clk_get_sys() if DT indicates no entry
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On Sat, Apr 26, 2014 at 10:49 AM, Russell King
<rmk+kernel@arm.linux.org.uk> wrote:
> There are two failures which DT can return when looking up a phandle:
> -ENOENT - when DT finds that the desired property/index is not present
> -EINVAL - when DT finds that the desired property/index is present, but
> there is a problem parsing it.
>
> We should only fall through to clk_get_sys() (the table driven clock
> lookup) when DT indicates that there was no entry in the OF tables
> for the clock. Doing otherwise causes the clk API to always indicate
> that there is no entry for this clock, which is not correct behaviour.
>
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> ---
> Grant, Rob,
>
> Please let me know ASAP if this gives you any cause for concern. This
> looks to me like a long standing bug which really needs fixing. Part
> of the motivation here is similar to Jean-Francois' patch to clkdev
> which allows a DT specified clock which isn't get present to have
> clk_get() and friends return -EPROBE_DEFER - again, something that I
> think really should happen. Jean-Francois hasn't been able to get
> much traction for his patch, so let's start with fixing this bug first.

I have no issues. A platform would have to be pretty broken to be
relying on the current behavior.

Rob

>
> drivers/clk/clkdev.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
> index 48f67218247c..4e65d0e10b05 100644
> --- a/drivers/clk/clkdev.c
> +++ b/drivers/clk/clkdev.c
> @@ -165,7 +165,7 @@ struct clk *clk_get(struct device *dev, const char *con_id)
>
> if (dev) {
> clk = of_clk_get_by_name(dev->of_node, con_id);
> - if (!IS_ERR(clk))
> + if (!IS_ERR(clk) || PTR_ERR(clk) != -ENOENT)
> return clk;
> }
>
> --
> 1.8.3.1
>


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