linux-kernel - Re: [PATCH] Fix returns of some CLK API calls, if !CONFIG_HAVE

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Message-ID: <20170425163137.GR17774@n2100.armlinux.org.uk>
Date:   Tue, 25 Apr 2017 17:31:37 +0100
From:   Russell King - ARM Linux <linux@...linux.org.uk>
To:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>
Cc:     linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mips@...ux-mips.org
Subject: Re: [PATCH] Fix returns of some CLK API calls, if !CONFIG_HAVE_CLOCK

On Tue, Apr 25, 2017 at 02:30:07PM +0200, Thomas Bogendoerfer wrote:
> If CONFIG_HAVE_CLOCK is not set, return values of clk_get(),
> devm_clk_get(), devm_get_clk_from_child(), clk_get_parent()
> and clk_get_sys() are wrong. According to spec these functions
> should either return a pointer to a struct clk or a valid IS_ERR
> condition. NULL is neither, so returning ERR_PTR(-ENODEV) makes
> more sense.

That's wrong.  When the clk API is disabled, the expected behaviour is
that drivers will not fail.  Returning ERR_PTR(-ENODEV) will cause them
to fail, so will break platforms.

NAK.

> Without this change serial console on SNI RM400 machines (MIPS arch)
> is broken, because sccnxp driver doesn't get a valid clock rate.

So the driver needs to depend on HAVE_CLOCK.

-- 
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