linux-kernel - Re: [PATCH] clocksource: Ingenic: Improve the code.

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Message-Id: <OQZQWQ.MUGEDOGBXJW12@crapouillou.net>
Date:   Sat, 24 Jul 2021 12:54:24 +0100
From:   Paul Cercueil <paul@...pouillou.net>
To:     周琰杰 <zhouyanjie@...yeetech.com>
Cc:     daniel.lezcano@...aro.org, tglx@...utronix.de,
        linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
        dongsheng.qiu@...enic.com, aric.pzqi@...enic.com,
        rick.tyliu@...enic.com, sihui.liu@...enic.com,
        jun.jiang@...enic.com, sernia.zhou@...mail.com
Subject: Re: [PATCH] clocksource: Ingenic: Improve the code.

Hi Zhou,

Thanks! I actually had a similar patch locally that I was eventually 
going to send.


Le sam., juil. 24 2021 at 18:10:07 +0800, 周琰杰 (Zhou Yanjie) 
<zhouyanjie@...yeetech.com> a écrit :
> Use "FIELD_GET()" and "FIELD_PREP()" to simplify the code.
> 
> Signed-off-by: 周琰杰 (Zhou Yanjie) <zhouyanjie@...yeetech.com>
> ---
>  drivers/clocksource/ingenic-sysost.c | 11 +++++------
>  1 file changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/clocksource/ingenic-sysost.c 
> b/drivers/clocksource/ingenic-sysost.c
> index a129840..1fbea59 100644
> --- a/drivers/clocksource/ingenic-sysost.c
> +++ b/drivers/clocksource/ingenic-sysost.c
> @@ -4,6 +4,7 @@
>   * Copyright (c) 2020 周琰杰 (Zhou Yanjie) 
> <zhouyanjie@...yeetech.com>
>   */
> 
> +#include <linux/bitfield.h>
>  #include <linux/bitops.h>
>  #include <linux/clk.h>
>  #include <linux/clk-provider.h>
> @@ -34,8 +35,6 @@
>  /* bits within the OSTCCR register */
>  #define OSTCCR_PRESCALE1_MASK	0x3
>  #define OSTCCR_PRESCALE2_MASK	0xc
> -#define OSTCCR_PRESCALE1_LSB	0
> -#define OSTCCR_PRESCALE2_LSB	2
> 
>  /* bits within the OSTCR register */
>  #define OSTCR_OST1CLR			BIT(0)
> @@ -98,7 +97,7 @@ static unsigned long 
> ingenic_ost_percpu_timer_recalc_rate(struct clk_hw *hw,
> 
>  	prescale = readl(ost_clk->ost->base + info->ostccr_reg);
> 
> -	prescale = (prescale & OSTCCR_PRESCALE1_MASK) >> 
> OSTCCR_PRESCALE1_LSB;
> +	prescale = FIELD_GET(OSTCCR_PRESCALE1_MASK, prescale);
> 
>  	return parent_rate >> (prescale * 2);
>  }
> @@ -112,7 +111,7 @@ static unsigned long 
> ingenic_ost_global_timer_recalc_rate(struct clk_hw *hw,
> 
>  	prescale = readl(ost_clk->ost->base + info->ostccr_reg);
> 
> -	prescale = (prescale & OSTCCR_PRESCALE2_MASK) >> 
> OSTCCR_PRESCALE2_LSB;
> +	prescale = FIELD_GET(OSTCCR_PRESCALE2_MASK, prescale);
> 
>  	return parent_rate >> (prescale * 2);
>  }
> @@ -151,7 +150,7 @@ static int 
> ingenic_ost_percpu_timer_set_rate(struct clk_hw *hw, unsigned long re
>  	int val;
> 
>  	val = readl(ost_clk->ost->base + info->ostccr_reg);
> -	val = (val & ~OSTCCR_PRESCALE1_MASK) | (prescale << 
> OSTCCR_PRESCALE1_LSB);
> +	val = (val & ~OSTCCR_PRESCALE1_MASK) | 
> FIELD_PREP(OSTCCR_PRESCALE1_MASK, prescale);

Just one nitpick, I'd prefer this:

val ~= &OSTCCR_PRESCALE1_MASK;
val |= FIELD_PREP(OSTCCR_PRESCALE1_MASK, prescale);

>  	writel(val, ost_clk->ost->base + info->ostccr_reg);
> 
>  	return 0;
> @@ -166,7 +165,7 @@ static int 
> ingenic_ost_global_timer_set_rate(struct clk_hw *hw, unsigned long re
>  	int val;
> 
>  	val = readl(ost_clk->ost->base + info->ostccr_reg);
> -	val = (val & ~OSTCCR_PRESCALE2_MASK) | (prescale << 
> OSTCCR_PRESCALE2_LSB);
> +	val = (val & ~OSTCCR_PRESCALE2_MASK) | 
> FIELD_PREP(OSTCCR_PRESCALE2_MASK, prescale);

Same here.

Cheers,
-Paul

>  	writel(val, ost_clk->ost->base + info->ostccr_reg);
> 
>  	return 0;
> --
> 2.7.4
>