linux-kernel - Re: [PATCH v3 04/16] ARM: davinci: Move clock init after ioremap.

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Message-ID: <570B6B09.8060907@ti.com>
Date:	Mon, 11 Apr 2016 14:44:49 +0530
From:	Sekhar Nori <nsekhar@...com>
To:	David Lechner <david@...hnology.com>
CC:	<petr@...ix.com>, <sergei.shtylyov@...entembedded.com>,
	<David.Laight@...LAB.COM>, Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Russell King <linux@....linux.org.uk>,
	Kevin Hilman <khilman@...nel.org>,
	Kishon Vijay Abraham I <kishon@...com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Alan Stern <stern@...land.harvard.edu>, Bin Liu <b-liu@...com>,
	Lee Jones <lee.jones@...aro.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@...r.kernel.org>,
	open list <linux-kernel@...r.kernel.org>,
	"moderated list:ARM PORT" <linux-arm-kernel@...ts.infradead.org>,
	"open list:USB SUBSYSTEM" <linux-usb@...r.kernel.org>
Subject: Re: [PATCH v3 04/16] ARM: davinci: Move clock init after ioremap.

On Friday 25 March 2016 05:21 AM, David Lechner wrote:
> Some clocks (such as the USB PHY clocks in DA8xx) will need to use iomem.
> The davinci_common_init() function must be called before the ioremap, so
> the clock init is now split out as separate function.
> 
> Signed-off-by: David Lechner <david@...hnology.com>
> ---
> 
> v3 changes: This is a new patch. It takes care of the issue of unwanted ioremap
> in clock set_parent functions.
> 
> 
>  arch/arm/mach-davinci/clock.c  | 4 ++--
>  arch/arm/mach-davinci/clock.h  | 7 ++++++-
>  arch/arm/mach-davinci/common.c | 6 ------
>  arch/arm/mach-davinci/da830.c  | 2 ++
>  arch/arm/mach-davinci/da850.c  | 2 ++
>  arch/arm/mach-davinci/dm355.c  | 1 +
>  arch/arm/mach-davinci/dm365.c  | 1 +
>  arch/arm/mach-davinci/dm644x.c | 1 +
>  arch/arm/mach-davinci/dm646x.c | 1 +
>  9 files changed, 16 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/arm/mach-davinci/clock.c b/arch/arm/mach-davinci/clock.c
> index 3424eac6..a5c2629 100644
> --- a/arch/arm/mach-davinci/clock.c
> +++ b/arch/arm/mach-davinci/clock.c
> @@ -560,7 +560,7 @@ EXPORT_SYMBOL(davinci_set_pllrate);
>   * than that used by default in <soc>.c file. The reference clock rate
>   * should be updated early in the boot process; ideally soon after the
>   * clock tree has been initialized once with the default reference clock
> - * rate (davinci_common_init()).
> + * rate (davinci_clk_init()).
>   *
>   * Returns 0 on success, error otherwise.
>   */
> @@ -581,7 +581,7 @@ int davinci_set_refclk_rate(unsigned long rate)
>  	return 0;
>  }
>  
> -int __init davinci_clk_init(struct clk_lookup *clocks)
> +int __init _davinci_clk_init(struct clk_lookup *clocks)
>  {
>  	struct clk_lookup *c;
>  	struct clk *clk;
> diff --git a/arch/arm/mach-davinci/clock.h b/arch/arm/mach-davinci/clock.h
> index 1e4e836..8b0fbbe 100644
> --- a/arch/arm/mach-davinci/clock.h
> +++ b/arch/arm/mach-davinci/clock.h
> @@ -124,7 +124,12 @@ struct clk {
>  		.clk = ck,	\
>  	}			\
>  
> -int davinci_clk_init(struct clk_lookup *clocks);
> +int _davinci_clk_init(struct clk_lookup *clocks);
> +static inline void davinci_clk_init(struct davinci_soc_info *soc_info)
> +{
> +	if (soc_info->cpu_clks && _davinci_clk_init(soc_info->cpu_clks))
> +		panic("davinci_clk_init: Failed to init clocks.\n");
> +}

I am not sure about the need for an additional API (_davinci_clk_init)
especially when you end up exposing both through clock.h. Just make make
calls from SoC files like:

	davinci_clk_init(davinci_soc_info_da830.cpu_clks);

I would ignore the panic() call too since davinci_clk_init() does not
really return an error (never has).

Thanks,
Sekhar