Received-SPF: pass (google.com: domain of linux-kernel+bounces-201073-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Message-ID: <af024ad1-93f6-4d7a-b139-7eb2fa12eb81@collabora.com>
Date: Tue, 4 Jun 2024 18:29:57 +0200
Precedence: bulk
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH] thermal/drivers/mediatek/lvts_thermal: Return error in
 case of invalid efuse data
To: Julien Panis <jpanis@baylibre.com>, "Rafael J. Wysocki"
 <rafael@kernel.org>, Daniel Lezcano <daniel.lezcano@linaro.org>,
 Zhang Rui <rui.zhang@intel.com>, Lukasz Luba <lukasz.luba@arm.com>,
 Matthias Brugger <matthias.bgg@gmail.com>,
 Nicolas Pitre <npitre@baylibre.com>
Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
 linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org
References: <20240603-mtk-thermal-calib-check-v1-1-5d6bf040414c@baylibre.com>
From: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Content-Language: en-US
In-Reply-To: <20240603-mtk-thermal-calib-check-v1-1-5d6bf040414c@baylibre.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit

Il 03/06/24 14:06, Julien Panis ha scritto:
> This patch prevents from registering thermal entries and letting the
> driver misbehave if efuse data is invalid. A device is not properly
> calibrated if the golden temperature is zero.
> 
> Signed-off-by: Julien Panis <jpanis@baylibre.com>

Fixes tag, please.

Regards,
Angelo

> ---
> Guard against invalid calibration data, following this discussion:
> https://lore.kernel.org/all/ad047631-16b8-42ce-8a8d-1429e6af4517@collabora.com/
> ---
>   drivers/thermal/mediatek/lvts_thermal.c | 6 +++++-
>   1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/mediatek/lvts_thermal.c b/drivers/thermal/mediatek/lvts_thermal.c
> index 0bb3a495b56e..185d5a32711f 100644
> --- a/drivers/thermal/mediatek/lvts_thermal.c
> +++ b/drivers/thermal/mediatek/lvts_thermal.c
> @@ -769,7 +769,11 @@ static int lvts_golden_temp_init(struct device *dev, u8 *calib,
>   	 */
>   	gt = (((u32 *)calib)[0] >> lvts_data->gt_calib_bit_offset) & 0xff;
>   
> -	if (gt && gt < LVTS_GOLDEN_TEMP_MAX)
> +	/* A zero value for gt means that device has invalid efuse data */
> +	if (!gt)
> +		return -ENODATA;
> +
> +	if (gt < LVTS_GOLDEN_TEMP_MAX)
>   		golden_temp = gt;
>   
>   	golden_temp_offset = golden_temp * 500 + lvts_data->temp_offset;
> 
> ---
> base-commit: 632483ea8004edfadd035de36e1ab2c7c4f53158
> change-id: 20240603-mtk-thermal-calib-check-ba2ec24a1c32
> 
> Best regards,