linux-kernel - Re: [PATCH v2 2/4] clk: bcm/kona: use DIV_ROUND_CLOSEST

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Message-ID: <5511A6EF.8010103@ieee.org>
Date:	Tue, 24 Mar 2015 13:03:27 -0500
From:	Alex Elder <elder@...e.org>
To:	Javi Merino <javi.merino@....com>, akpm@...ux-foundation.org
CC:	intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org, emil.l.velikov@...il.com,
	jepler@...ythonic.net, daniel@...ll.ch,
	Mike Turquette <mturquette@...aro.org>,
	Stephen Boyd <sboyd@...eaurora.org>,
	Alex Elder <elder@...aro.org>
Subject: Re: [PATCH v2 2/4] clk: bcm/kona: use DIV_ROUND_CLOSEST_ULL()

On 03/24/2015 09:03 AM, Javi Merino wrote:
> Now that the kernel provides DIV_ROUND_CLOSEST_ULL(), drop the internal
> implementation and use the kernel one.
> 
> Cc: Mike Turquette <mturquette@...aro.org>
> Cc: Stephen Boyd <sboyd@...eaurora.org>
> Cc: Alex Elder <elder@...aro.org>

Acked-by: Alex Elder <elder@...aro.org>

> Signed-off-by: Javi Merino <javi.merino@....com>
> ---
>  drivers/clk/bcm/clk-kona.c | 28 +++++++---------------------
>  drivers/clk/bcm/clk-kona.h |  1 -
>  2 files changed, 7 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/clk/bcm/clk-kona.c b/drivers/clk/bcm/clk-kona.c
> index 05abae89262e..a0ef4f75d457 100644
> --- a/drivers/clk/bcm/clk-kona.c
> +++ b/drivers/clk/bcm/clk-kona.c
> @@ -15,6 +15,7 @@
>  #include "clk-kona.h"
>  
>  #include <linux/delay.h>
> +#include <linux/kernel.h>
>  
>  /*
>   * "Policies" affect the frequencies of bus clocks provided by a
> @@ -51,21 +52,6 @@ static inline u32 bitfield_replace(u32 reg_val, u32 shift, u32 width, u32 val)
>  
>  /* Divider and scaling helpers */
>  
> -/*
> - * Implement DIV_ROUND_CLOSEST() for 64-bit dividend and both values
> - * unsigned.  Note that unlike do_div(), the remainder is discarded
> - * and the return value is the quotient (not the remainder).
> - */
> -u64 do_div_round_closest(u64 dividend, unsigned long divisor)
> -{
> -	u64 result;
> -
> -	result = dividend + ((u64)divisor >> 1);
> -	(void)do_div(result, divisor);
> -
> -	return result;
> -}
> -
>  /* Convert a divider into the scaled divisor value it represents. */
>  static inline u64 scaled_div_value(struct bcm_clk_div *div, u32 reg_div)
>  {
> @@ -87,7 +73,7 @@ u64 scaled_div_build(struct bcm_clk_div *div, u32 div_value, u32 billionths)
>  	combined = (u64)div_value * BILLION + billionths;
>  	combined <<= div->u.s.frac_width;
>  
> -	return do_div_round_closest(combined, BILLION);
> +	return DIV_ROUND_CLOSEST_ULL(combined, BILLION);
>  }
>  
>  /* The scaled minimum divisor representable by a divider */
> @@ -731,7 +717,7 @@ static unsigned long clk_recalc_rate(struct ccu_data *ccu,
>  		scaled_rate = scale_rate(pre_div, parent_rate);
>  		scaled_rate = scale_rate(div, scaled_rate);
>  		scaled_div = divider_read_scaled(ccu, pre_div);
> -		scaled_parent_rate = do_div_round_closest(scaled_rate,
> +		scaled_parent_rate = DIV_ROUND_CLOSEST_ULL(scaled_rate,
>  							scaled_div);
>  	} else  {
>  		scaled_parent_rate = scale_rate(div, parent_rate);
> @@ -743,7 +729,7 @@ static unsigned long clk_recalc_rate(struct ccu_data *ccu,
>  	 * rate.
>  	 */
>  	scaled_div = divider_read_scaled(ccu, div);
> -	result = do_div_round_closest(scaled_parent_rate, scaled_div);
> +	result = DIV_ROUND_CLOSEST_ULL(scaled_parent_rate, scaled_div);
>  
>  	return (unsigned long)result;
>  }
> @@ -790,7 +776,7 @@ static long round_rate(struct ccu_data *ccu, struct bcm_clk_div *div,
>  		scaled_rate = scale_rate(pre_div, parent_rate);
>  		scaled_rate = scale_rate(div, scaled_rate);
>  		scaled_pre_div = divider_read_scaled(ccu, pre_div);
> -		scaled_parent_rate = do_div_round_closest(scaled_rate,
> +		scaled_parent_rate = DIV_ROUND_CLOSEST_ULL(scaled_rate,
>  							scaled_pre_div);
>  	} else {
>  		scaled_parent_rate = scale_rate(div, parent_rate);
> @@ -802,7 +788,7 @@ static long round_rate(struct ccu_data *ccu, struct bcm_clk_div *div,
>  	 * the best we can do.
>  	 */
>  	if (!divider_is_fixed(div)) {
> -		best_scaled_div = do_div_round_closest(scaled_parent_rate,
> +		best_scaled_div = DIV_ROUND_CLOSEST_ULL(scaled_parent_rate,
>  							rate);
>  		min_scaled_div = scaled_div_min(div);
>  		max_scaled_div = scaled_div_max(div);
> @@ -815,7 +801,7 @@ static long round_rate(struct ccu_data *ccu, struct bcm_clk_div *div,
>  	}
>  
>  	/* OK, figure out the resulting rate */
> -	result = do_div_round_closest(scaled_parent_rate, best_scaled_div);
> +	result = DIV_ROUND_CLOSEST_ULL(scaled_parent_rate, best_scaled_div);
>  
>  	if (scaled_div)
>  		*scaled_div = best_scaled_div;
> diff --git a/drivers/clk/bcm/clk-kona.h b/drivers/clk/bcm/clk-kona.h
> index 2537b3072910..6849a64baf6d 100644
> --- a/drivers/clk/bcm/clk-kona.h
> +++ b/drivers/clk/bcm/clk-kona.h
> @@ -503,7 +503,6 @@ extern struct clk_ops kona_peri_clk_ops;
>  
>  /* Externally visible functions */
>  
> -extern u64 do_div_round_closest(u64 dividend, unsigned long divisor);
>  extern u64 scaled_div_max(struct bcm_clk_div *div);
>  extern u64 scaled_div_build(struct bcm_clk_div *div, u32 div_value,
>  				u32 billionths);
> 

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