thermal: stm32: read factory settings inside stm_thermal_prepare

Calling stm_thermal_read_factory_settings before clocking
internal peripheral causes bad register values and makes
temperature computation wrong.

Calling stm_thermal_read_factory_settings inside
stm_thermal_prepare fixes this problem as internal
peripheral is well clocked at this stage.

Fixes: 1d693155 ("thermal: add stm32 thermal driver")
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: David Hernandez Sanchez <david.hernandezsanchez@st.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>

drivers/thermal/st/stm_thermal.c

@@ -532,6 +532,10 @@ static int stm_thermal_prepare(struct stm_thermal_sensor *sensor)
 	if (ret)
 		return ret;
 
+	ret = stm_thermal_read_factory_settings(sensor);
+	if (ret)
+		goto thermal_unprepare;
+
 	ret = stm_thermal_calibration(sensor);
 	if (ret)
 		goto thermal_unprepare;
@@ -636,10 +640,6 @@ static int stm_thermal_probe(struct platform_device *pdev)
 	/* Populate sensor */
 	sensor->base = base;
 
-	ret = stm_thermal_read_factory_settings(sensor);
-	if (ret)
-		return ret;
-
 	sensor->clk = devm_clk_get(&pdev->dev, "pclk");
 	if (IS_ERR(sensor->clk)) {
 		dev_err(&pdev->dev, "%s: failed to fetch PCLK clock\n",