linux-kernel - Re: [PATCH 5/7] gpio: omap: fix clk

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Date:	Wed, 26 Aug 2015 09:52:02 +0200
From:	Linus Walleij <linus.walleij@...aro.org>
To:	Grygorii Strashko <grygorii.strashko@...com>
Cc:	Alexandre Courbot <gnurou@...il.com>,
	Santosh Shilimkar <ssantosh@...nel.org>,
	Kevin Hilman <khilman@...prootsystems.com>,
	Tony Lindgren <tony@...mide.com>,
	Javier Martinez Canillas <javier@...hile0.org>,
	Linux-OMAP <linux-omap@...r.kernel.org>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/7] gpio: omap: fix clk_prepare/unprepare usage

On Tue, Aug 18, 2015 at 1:10 PM, Grygorii Strashko
<grygorii.strashko@...com> wrote:

> As per CCF documentation (clk.txt) the clk_prepare/unprepare APIs
> are not allowed in atomic context. But now OMAP GPIO driver
> uses them while applying debounce settings and as part
> of PM runtime irqsafe operations:
>
> - omap_gpio_debounce() is holding the lock with IRQs off.
>   + omap2_set_gpio_debounce()
>    + clk_prepare_enable()
>     + clk_prepare() this one might sleep.
>
> - pm_runtime_get_sync() is holding the lock with IRQs off
>   + omap_gpio_runtime_suspend()
>     + raw_spin_lock_irqsave()
>     + omap_gpio_dbck_disable()
>       + clk_disable_unprepare()
>
> Hence, fix it by moeving dbclk prepare/unprepare in OMAP GPIO
> omap_gpio_probe/omap_gpio_remove. Also, while here, ensure that
> debounce functionality is disabled if clk_get() failed,
> because otherwise kernel will carsh in omap2_set_gpio_debounce().
>
> Reported-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
> Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>

Patch applied.

Yours,
Linus Walleij
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