linux-kernel - Re: [PATCH v5] clk: Add write operation for clk

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Message-ID: <YWXaKevf8D0kKYXo@smile.fi.intel.com>
Date:   Tue, 12 Oct 2021 21:55:37 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Sam Protsenko <semen.protsenko@...aro.org>
Cc:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Sylwester Nawrocki <s.nawrocki@...sung.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
        Mike Tipton <mdtipton@...eaurora.org>,
        Andy Shevchenko <andy@...nel.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Fabio Estevam <festevam@...il.com>, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5] clk: Add write operation for clk_parent debugfs node

On Thu, Oct 07, 2021 at 09:21:58PM +0300, Sam Protsenko wrote:
> Useful for testing mux clocks. One can write the index of the parent to
> be set into clk_parent node, starting from 0. Example
> 
>     # cd /sys/kernel/debug/clk/mout_peri_bus
>     # cat clk_possible_parents
>       dout_shared0_div4 dout_shared1_div4
>     # cat clk_parent
>       dout_shared0_div4
>     # echo 1 > clk_parent
>     # cat clk_parent
>       dout_shared1_div4
> 
> CLOCK_ALLOW_WRITE_DEBUGFS has to be defined in drivers/clk/clk.c in
> order to use this feature.

...

> +#ifdef CLOCK_ALLOW_WRITE_DEBUGFS
> +	if (core->num_parents > 1)
> +		debugfs_create_file("clk_parent", 0644, root, core,
> +				    &current_parent_rw_fops);
> +	else
> +#endif

> +	{
> +		if (core->num_parents > 0)
> +			debugfs_create_file("clk_parent", 0444, root, core,
> +					    &current_parent_fops);
> +	}

Currently there is no need to add the {} along with increased indentation
level. I.o.w. the 'else if' is valid in C.

-- 
With Best Regards,
Andy Shevchenko