linux-kernel - Re: [v4,7/7] thermal: mediatek: use spinlock to protect PTPCORESEL

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Date:   Fri, 22 May 2020 17:36:45 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Michael Kao <michael.kao@...iatek.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Zhang Rui <rui.zhang@...el.com>,
        Eduardo Valentin <edubezval@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>, hsinyi@...omium.org,
        linux-pm@...r.kernel.org, srv_heupstream@...iatek.com
Cc:     devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org
Subject: Re: [v4,7/7] thermal: mediatek: use spinlock to protect PTPCORESEL

On 23/03/2020 13:15, Michael Kao wrote:
> From: "michael.kao" <michael.kao@...iatek.com>
> 
> The driver of thermal and svs will use the
> same register for the project which should select
> bank before reading sensor value.

Here there is a design problem AFAICT. The sensor should not be using
external locks.



> Signed-off-by: Michael Kao <michael.kao@...iatek.com>
> ---
>  drivers/thermal/mtk_thermal.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/thermal/mtk_thermal.c b/drivers/thermal/mtk_thermal.c
> index 9eaca432920e..594ad4f0f8cd 100644
> --- a/drivers/thermal/mtk_thermal.c
> +++ b/drivers/thermal/mtk_thermal.c
> @@ -22,6 +22,7 @@
>  #include <linux/thermal.h>
>  #include <linux/reset.h>
>  #include <linux/types.h>
> +#include <linux/power/mtk_svs.h>
>  
>  /* AUXADC Registers */
>  #define AUXADC_CON1_SET_V	0x008
> @@ -262,7 +263,7 @@ struct mtk_thermal {
>  	struct clk *clk_peri_therm;
>  	struct clk *clk_auxadc;
>  	/* lock: for getting and putting banks */
> -	struct mutex lock;
> +	unsigned long flags;
>  
>  	/* Calibration values */
>  	s32 adc_ge;
> @@ -561,7 +562,7 @@ static void mtk_thermal_get_bank(struct mtk_thermal_bank *bank)
>  	u32 val;
>  
>  	if (mt->conf->need_switch_bank) {
> -		mutex_lock(&mt->lock);
> +		mt->flags = claim_mtk_svs_lock();
>  
>  		val = readl(mt->thermal_base + PTPCORESEL);
>  		val &= ~0xf;
> @@ -581,7 +582,7 @@ static void mtk_thermal_put_bank(struct mtk_thermal_bank *bank)
>  	struct mtk_thermal *mt = bank->mt;
>  
>  	if (mt->conf->need_switch_bank)
> -		mutex_unlock(&mt->lock);
> +		release_mtk_svs_lock(mt->flags);
>  }
>  
>  /**
> @@ -938,8 +939,6 @@ static int mtk_thermal_probe(struct platform_device *pdev)
>  	if (ret)
>  		return ret;
>  
> -	mutex_init(&mt->lock);
> -
>  	mt->dev = &pdev->dev;
>  
>  	auxadc = of_parse_phandle(np, "mediatek,auxadc", 0);
> 


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