linux-kernel - Re: [PATCH v4 3/9] thermal/drivers/mediatek/lvts: Fail probe if temp

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Message-ID: <190003b6-2931-406a-a8f6-ec8909c65162@linaro.org>
Date: Mon, 24 Nov 2025 18:56:29 +0100
From: Daniel Lezcano <daniel.lezcano@...aro.org>
To: Laura Nao <laura.nao@...labora.com>, srini@...nel.org, robh@...nel.org,
 krzk+dt@...nel.org, conor+dt@...nel.org, rafael@...nel.org,
 rui.zhang@...el.com, lukasz.luba@....com, matthias.bgg@...il.com,
 angelogioacchino.delregno@...labora.com
Cc: nfraprado@...labora.com, arnd@...db.de, colin.i.king@...il.com,
 u.kleine-koenig@...libre.com, andrew-ct.chen@...iatek.com,
 lala.lin@...iatek.com, bchihi@...libre.com, frank-w@...lic-files.de,
 wenst@...omium.org, fshao@...omium.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-mediatek@...ts.infradead.org,
 kernel@...labora.com
Subject: Re: [PATCH v4 3/9] thermal/drivers/mediatek/lvts: Fail probe if
 temp_factor is zero

On 11/21/25 12:16, Laura Nao wrote:
> temp_factor is used in lvts_temp_to_raw() and lvts_raw_to_temp(). If
> platform data is incorrect and temp_factor is zero, it could cause a
> division by zero. Fail the probe early to prevent a kernel crash.
> 
> Signed-off-by: Laura Nao <laura.nao@...labora.com>
> ---
>   drivers/thermal/mediatek/lvts_thermal.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/thermal/mediatek/lvts_thermal.c b/drivers/thermal/mediatek/lvts_thermal.c
> index 1c54d0b75b1a..b49441d82ffd 100644
> --- a/drivers/thermal/mediatek/lvts_thermal.c
> +++ b/drivers/thermal/mediatek/lvts_thermal.c
> @@ -1346,6 +1346,11 @@ static int lvts_probe(struct platform_device *pdev)
>   	if (irq < 0)
>   		return irq;
>   
> +	if (!lvts_data->temp_factor)
> +		return dev_err_probe(
> +			dev, -EINVAL,
> +			"temp_factor should never be zero; check platform data.\n");
> +

 From my POV, this is not really useful. The temp_factor is set for each 
version statically in the code. The scope is limited to the driver, IOW 
it is not a parameter other subsystems passes to the driver.

If it is NULL, then shame on the submitter who did not test the driver 
before sending ;)



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