linux-kernel - Re: [PATCH v2 2/5] clk: sunxi-ng: mux: support fixed pre-dividers on multiple parents

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Message-ID: <20160823085534.GC2598@lukather>
Date:   Tue, 23 Aug 2016 10:55:34 +0200
From:   Maxime Ripard <maxime.ripard@...e-electrons.com>
To:     Chen-Yu Tsai <wens@...e.org>
Cc:     Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...eaurora.org>, linux-clk@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v2 2/5] clk: sunxi-ng: mux: support fixed pre-dividers on
 multiple parents

On Mon, Aug 15, 2016 at 04:13:12PM +0800, Chen-Yu Tsai wrote:
> Some clocks on the A31 have fixed pre-dividers on multiple parents.
> Add support for them.
> 
> Signed-off-by: Chen-Yu Tsai <wens@...e.org>
> ---
> Changes since v1:
> 
>   - Add field for number of fixed pre-dividers.
> ---
>  drivers/clk/sunxi-ng/ccu-sun8i-h3.c |  9 +++++----
>  drivers/clk/sunxi-ng/ccu_mux.c      |  6 ++++--
>  drivers/clk/sunxi-ng/ccu_mux.h      | 11 +++++++----
>  3 files changed, 16 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/clk/sunxi-ng/ccu-sun8i-h3.c b/drivers/clk/sunxi-ng/ccu-sun8i-h3.c
> index 9af359544110..a01298881991 100644
> --- a/drivers/clk/sunxi-ng/ccu-sun8i-h3.c
> +++ b/drivers/clk/sunxi-ng/ccu-sun8i-h3.c
> @@ -184,15 +184,16 @@ static SUNXI_CCU_MP_WITH_MUX(apb2_clk, "apb2", apb2_parents, 0x058,
>  			     0);
>  
>  static const char * const ahb2_parents[] = { "ahb1" , "pll-periph0" };
> +static const struct ccu_mux_fixed_prediv ahb2_fixed_predivs[] = {
> +	{ .index = 1, .div = 2 },
> +	{ },
> +};
>  static struct ccu_mux ahb2_clk = {
>  	.mux		= {
>  		.shift	= 0,
>  		.width	= 1,
>  
> -		.fixed_prediv	= {
> -			.index	= 1,
> -			.div	= 2,
> -		},
> +		.fixed_predivs	= ahb2_fixed_predivs,
>  	},
>  
>  	.common		= {
> diff --git a/drivers/clk/sunxi-ng/ccu_mux.c b/drivers/clk/sunxi-ng/ccu_mux.c
> index 68b32f168a74..7b17e0c26b01 100644
> --- a/drivers/clk/sunxi-ng/ccu_mux.c
> +++ b/drivers/clk/sunxi-ng/ccu_mux.c
> @@ -20,6 +20,7 @@ void ccu_mux_helper_adjust_parent_for_prediv(struct ccu_common *common,
>  {
>  	u16 prediv = 1;
>  	u32 reg;
> +	int i;
>  
>  	if (!((common->features & CCU_FEATURE_FIXED_PREDIV) ||
>  	      (common->features & CCU_FEATURE_VARIABLE_PREDIV)))
> @@ -32,8 +33,9 @@ void ccu_mux_helper_adjust_parent_for_prediv(struct ccu_common *common,
>  	}
>  
>  	if (common->features & CCU_FEATURE_FIXED_PREDIV)
> -		if (parent_index == cm->fixed_prediv.index)
> -			prediv = cm->fixed_prediv.div;
> +		for (i = 0; i < cm->n_predivs; i++)
> +			if (parent_index == cm->fixed_predivs[i].index)
> +				prediv = cm->fixed_predivs[i].div;
>  
>  	if (common->features & CCU_FEATURE_VARIABLE_PREDIV)
>  		if (parent_index == cm->variable_prediv.index) {
> diff --git a/drivers/clk/sunxi-ng/ccu_mux.h b/drivers/clk/sunxi-ng/ccu_mux.h
> index f0078de78712..5308b41da22a 100644
> --- a/drivers/clk/sunxi-ng/ccu_mux.h
> +++ b/drivers/clk/sunxi-ng/ccu_mux.h
> @@ -5,15 +5,18 @@
>  
>  #include "ccu_common.h"
>  
> +struct ccu_mux_fixed_prediv {
> +	u8	index;
> +	u16	div;
> +};
> +
>  struct ccu_mux_internal {
>  	u8		shift;
>  	u8		width;
>  	const u8	*table;
>  
> -	struct {
> -		u8	index;
> -		u16	div;
> -	} fixed_prediv;
> +	const struct ccu_mux_fixed_prediv	*fixed_predivs;
> +	u8		n_predivs;

I don't think you're using it anywhere (at least you don't define it
in ahb2_clk, and the extra item in the array will introduce an
off-by-one error.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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