linux-kernel - Re: [PATCH v4 2/9] thermal/drivers/mediatek/lvts: Make number of calibration offsets configurable

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Message-ID: <24a5bd31-a79f-4f18-a190-6a4d886a29b2@linaro.org>
Date: Mon, 24 Nov 2025 19:25:14 +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 2/9] thermal/drivers/mediatek/lvts: Make number of
 calibration offsets configurable

On 11/21/25 12:16, Laura Nao wrote:
> MT8196/MT6991 use 2-byte eFuse calibration data, whereas other SoCs
> supported by the driver rely on 3 bytes. Make the number of calibration
> bytes per sensor configurable, enabling support for SoCs with varying
> calibration formats.
> 
> Reviewed-by: Fei Shao <fshao@...omium.org>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> Tested-by: Frank Wunderlich <frank-w@...lic-files.de>
> Signed-off-by: Laura Nao <laura.nao@...labora.com>
> ---
>   drivers/thermal/mediatek/lvts_thermal.c | 32 ++++++++++++++++++++++----------
>   1 file changed, 22 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/thermal/mediatek/lvts_thermal.c b/drivers/thermal/mediatek/lvts_thermal.c
> index ab55b20cda47..1c54d0b75b1a 100644
> --- a/drivers/thermal/mediatek/lvts_thermal.c
> +++ b/drivers/thermal/mediatek/lvts_thermal.c
> @@ -96,12 +96,14 @@
>   
>   #define LVTS_MINIMUM_THRESHOLD		20000
>   
> +#define LVTS_MAX_CAL_OFFSETS		3

I suggest LVTS_NUM_CAL_OFFSETS then below,

> +
>   static int golden_temp = LVTS_GOLDEN_TEMP_DEFAULT;
>   static int golden_temp_offset;
>   
>   struct lvts_sensor_data {
>   	int dt_id;
> -	u8 cal_offsets[3];
> +	u8 cal_offsets[LVTS_MAX_CAL_OFFSETS];
>   };
>   
>   struct lvts_ctrl_data {
> @@ -127,6 +129,7 @@ struct lvts_data {
>   	const struct lvts_ctrl_data *lvts_ctrl;
>   	const u32 *conn_cmd;
>   	const u32 *init_cmd;
> +	int num_cal_offsets;
>   	int num_lvts_ctrl;
>   	int num_conn_cmd;
>   	int num_init_cmd;
> @@ -711,7 +714,7 @@ static int lvts_calibration_init(struct device *dev, struct lvts_ctrl *lvts_ctrl
>   					u8 *efuse_calibration,
>   					size_t calib_len)
>   {
> -	int i;
> +	int i, j;
>   	u32 gt;
>   
>   	/* A zero value for gt means that device has invalid efuse data */
> @@ -720,17 +723,18 @@ static int lvts_calibration_init(struct device *dev, struct lvts_ctrl *lvts_ctrl
>   	lvts_for_each_valid_sensor(i, lvts_ctrl_data) {
>   		const struct lvts_sensor_data *sensor =
>   					&lvts_ctrl_data->lvts_sensor[i];
> +		u32 calib = 0;
>   
> -		if (sensor->cal_offsets[0] >= calib_len ||
> -		    sensor->cal_offsets[1] >= calib_len ||
> -		    sensor->cal_offsets[2] >= calib_len)
> -			return -EINVAL;
> +		for (j = 0; j < lvts_ctrl->lvts_data->num_cal_offsets; j++) {
> +			u8 offset = sensor->cal_offsets[j];
> +
> +			if (offset >= calib_len)
> +				return -EINVAL;
> +			calib |= efuse_calibration[offset] << (8 * j);

May be worth for a comment here, ideally a separate function to clarify 
the code

> +		}
>   
>   		if (gt) {
> -			lvts_ctrl->calibration[i] =
> -				(efuse_calibration[sensor->cal_offsets[0]] << 0) +
> -				(efuse_calibration[sensor->cal_offsets[1]] << 8) +
> -				(efuse_calibration[sensor->cal_offsets[2]] << 16);
> +			lvts_ctrl->calibration[i] = calib;
>   		} else if (lvts_ctrl->lvts_data->def_calibration) {
>   			lvts_ctrl->calibration[i] = lvts_ctrl->lvts_data->def_calibration;
>   		} else {
> @@ -1763,6 +1767,7 @@ static const struct lvts_data mt7988_lvts_ap_data = {
>   	.temp_factor	= LVTS_COEFF_A_MT7988,
>   	.temp_offset	= LVTS_COEFF_B_MT7988,
>   	.gt_calib_bit_offset = 24,
> +	.num_cal_offsets = 3,

LVTS_NUM_CAL_OFFSETS


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