iio: adc: qcom-vadc-common: rewrite vadc7 die temp calculation

qcom_vadc7_scale_hw_calib_die_temp() uses a table format different from
the rest of volt/temp conversion functions in this file. Also the
conversion functions results in non-monothonic values conversion, which
seems wrong.

Rewrite qcom_vadc7_scale_hw_calib_die_temp() to use
qcom_vadc_map_voltage_temp() directly, like the rest of conversion
functions do.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://lore.kernel.org/r/20201204025509.1075506-10-dmitry.baryshkov@linaro.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/qcom-vadc-common.c b/drivers/iio/adc/qcom-vadc-common.c
index 45a3860..0c705bb 100644 (file)
--- a/drivers/iio/adc/qcom-vadc-common.c
+++ b/drivers/iio/adc/qcom-vadc-common.c
@@ -101,18 +101,18 @@ static const struct vadc_map_pt adcmap_100k_104ef_104fb_1875_vref[] = {
 };
 
 static const struct vadc_map_pt adcmap7_die_temp[] = {
-       { 433700, 1967},
-       { 473100, 1964},
-       { 512400, 1957},
-       { 551500, 1949},
-       { 590500, 1940},
-       { 629300, 1930},
-       { 667900, 1921},
-       { 706400, 1910},
-       { 744600, 1896},
-       { 782500, 1878},
-       { 820100, 1859},
-       { 857300, 0},
+       { 857300, 160000 },
+       { 820100, 140000 },
+       { 782500, 120000 },
+       { 744600, 100000 },
+       { 706400, 80000 },
+       { 667900, 60000 },
+       { 629300, 40000 },
+       { 590500, 20000 },
+       { 551500, 0 },
+       { 512400, -20000 },
+       { 473100, -40000 },
+       { 433700, -60000 },
 };
 
 /*
@@ -585,33 +585,13 @@ static int qcom_vadc7_scale_hw_calib_die_temp(
                                u16 adc_code, int *result_mdec)
 {
 
-       int voltage, vtemp0, temp, i;
+       int voltage;
 
        voltage = qcom_vadc_scale_code_voltage_factor(adc_code,
                                prescale, data, 1);
 
-       if (adcmap7_die_temp[0].x > voltage) {
-               *result_mdec = DIE_TEMP_ADC7_SCALE_1;
-               return 0;
-       }
-
-       if (adcmap7_die_temp[ARRAY_SIZE(adcmap7_die_temp) - 1].x <= voltage) {
-               *result_mdec = DIE_TEMP_ADC7_MAX;
-               return 0;
-       }
-
-       for (i = 0; i < ARRAY_SIZE(adcmap7_die_temp); i++)
-               if (adcmap7_die_temp[i].x > voltage)
-                       break;
-
-       vtemp0 = adcmap7_die_temp[i - 1].x;
-       voltage = voltage - vtemp0;
-       temp = div64_s64(voltage * DIE_TEMP_ADC7_SCALE_FACTOR,
-               adcmap7_die_temp[i - 1].y);
-       temp += DIE_TEMP_ADC7_SCALE_1 + (DIE_TEMP_ADC7_SCALE_2 * (i - 1));
-       *result_mdec = temp;
-
-       return 0;
+       return qcom_vadc_map_voltage_temp(adcmap7_die_temp, ARRAY_SIZE(adcmap7_die_temp),
+                       voltage, result_mdec);
 }
 
 static int qcom_vadc_scale_hw_smb_temp(

diff --git a/include/linux/iio/adc/qcom-vadc-common.h b/include/linux/iio/adc/qcom-vadc-common.h
index 1d337dd..5821612 100644 (file)
--- a/include/linux/iio/adc/qcom-vadc-common.h
+++ b/include/linux/iio/adc/qcom-vadc-common.h
@@ -54,11 +54,6 @@
 #define R_PU_100K                              100000
 #define RATIO_MAX_ADC7                         BIT(14)
 
-#define DIE_TEMP_ADC7_SCALE_1                  -60000
-#define DIE_TEMP_ADC7_SCALE_2                  20000
-#define DIE_TEMP_ADC7_SCALE_FACTOR             1000
-#define DIE_TEMP_ADC7_MAX                      160000
-
 /*
  * VADC_CALIB_ABSOLUTE: uses the 625mV and 1.25V as reference channels.
  * VADC_CALIB_RATIOMETRIC: uses the reference voltage (1.8V) and GND for