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

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Message-Id: <20251125110639.23257-1-laura.nao@collabora.com>
Date: Tue, 25 Nov 2025 12:06:39 +0100
From: Laura Nao <laura.nao@...labora.com>
To: daniel.lezcano@...aro.org
Cc: andrew-ct.chen@...iatek.com,
	angelogioacchino.delregno@...labora.com,
	arnd@...db.de,
	bchihi@...libre.com,
	colin.i.king@...il.com,
	conor+dt@...nel.org,
	devicetree@...r.kernel.org,
	frank-w@...lic-files.de,
	fshao@...omium.org,
	kernel@...labora.com,
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	lala.lin@...iatek.com,
	laura.nao@...labora.com,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-mediatek@...ts.infradead.org,
	linux-pm@...r.kernel.org,
	lukasz.luba@....com,
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	wenst@...omium.org
Subject: Re: [PATCH v4 2/9] thermal/drivers/mediatek/lvts: Make number of calibration offsets configurable

On 11/24/25 19:25, Daniel Lezcano wrote:
> 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,
>

Right - as this is SoC-specific, I can define:

#define LVTS_NUM_CAL_OFFSETS_MT7988	3
#define LVTS_NUM_CAL_OFFSETS_MT8196	2

>> +
>>   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
>

Ack - will do.

>> +        }
>>             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
>
>

I'll submit a v5 with the required changes.

Thanks!

Laura