[PATCH v2 2/2] thermal/drivers/imx: Add calibration offset support
From: HaoNing Cheng via B4 Relay <devnull+Haoning.CHENG.cn.bosch.com@kernel.org>
Date: 2026-07-09 08:10:28
Also in:
b4-sent, imx, linux-devicetree, linux-pm, lkml
Subsystem:
the rest, thermal · Maintainers:
Linus Torvalds, Rafael J. Wysocki, Daniel Lezcano
From: HaoNing Cheng <redacted> Some boards need a small per-design correction to align the reported CPU temperature with board-level measurements. Read the optional fsl,temp-calibration-offset-millicelsius property from DT and apply it to the i.MX6/6SX/7D calibration formulas. When the property is not present, the default offset remains 0, preserving the current behaviour. Signed-off-by: HaoNing Cheng <redacted> --- drivers/thermal/imx_thermal.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
index 38c993d1bcb3..8062d34ffed8 100644
--- a/drivers/thermal/imx_thermal.c
+++ b/drivers/thermal/imx_thermal.c@@ -207,6 +207,7 @@ struct imx_thermal_data { struct regmap *tempmon; u32 c1, c2; /* See formula in imx_init_calib() */ int temp_max; + s32 calibration_offset; int alarm_temp; int last_temp; bool irq_enabled;
@@ -240,10 +241,13 @@ static void imx_set_alarm_temp(struct imx_thermal_data *data, data->alarm_temp = alarm_temp; - if (data->socdata->version == TEMPMON_IMX7D) - alarm_value = alarm_temp / 1000 + data->c1 - 25; - else + if (data->socdata->version == TEMPMON_IMX7D) { + alarm_value = DIV_ROUND_UP(alarm_temp - data->calibration_offset, + 1000) + data->c1 - 25; + alarm_value = clamp(alarm_value, 0, 0x1ff); + } else { alarm_value = (data->c2 - alarm_temp) / data->c1; + } regmap_write(map, soc_data->high_alarm_ctrl + REG_CLR, soc_data->high_alarm_mask);
@@ -274,7 +278,7 @@ static int imx_get_temp(struct thermal_zone_device *tz, int *temp) /* See imx_init_calib() for formula derivation */ if (data->socdata->version == TEMPMON_IMX7D) - *temp = (n_meas - data->c1 + 25) * 1000; + *temp = (n_meas - data->c1 + 25) * 1000 + data->calibration_offset; else *temp = data->c2 - n_meas * data->c1;
@@ -413,7 +417,7 @@ static int imx_init_calib(struct platform_device *pdev, u32 ocotp_ana1) temp64 *= 1000; /* to get result in °mC */ do_div(temp64, 15423 * n1 - 4148468); data->c1 = temp64; - data->c2 = n1 * data->c1 + 28581; + data->c2 = n1 * data->c1 + 28581 + data->calibration_offset; return 0; }
@@ -629,6 +633,10 @@ static int imx_thermal_probe(struct platform_device *pdev) platform_set_drvdata(pdev, data); + of_property_read_s32(dev->of_node, + "fsl,temp-calibration-offset-millicelsius", + &data->calibration_offset); + if (of_property_present(dev->of_node, "nvmem-cells")) { ret = imx_init_from_nvmem_cells(pdev); if (ret)
--
2.43.0