RE: [PATCH V1]iio: adc: spmi-vadc: Changes to support different scaling

From: Sricharan
Date: Tue Oct 25 2016 - 09:10:05 EST

Hi Ramakrishna,

>Add changes to support different scale functions to convert adc code to
>physical units.
>
>Signed-off-by: Rama Krishna Phani A <rphani@xxxxxxxxxxxxxx>
>---
> drivers/iio/adc/qcom-spmi-vadc.c | 319 ++++++++++++++++++++++++++++++---------
> 1 file changed, 249 insertions(+), 70 deletions(-)
>
>diff --git a/drivers/iio/adc/qcom-spmi-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c
>index c2babe5..e605a9d 100644
>--- a/drivers/iio/adc/qcom-spmi-vadc.c
>+++ b/drivers/iio/adc/qcom-spmi-vadc.c
>@@ -1,5 +1,5 @@
> /*
>- * Copyright (c) 2012-2014, The Linux Foundation. All rights reserved.
>+ * Copyright (c) 2012-2016, The Linux Foundation. All rights reserved.
> *
> * This program is free software; you can redistribute it and/or modify
> * it under the terms of the GNU General Public License version 2 and
>@@ -84,7 +84,7 @@
> #define VADC_MAX_ADC_CODE 0xa800
>
> #define VADC_ABSOLUTE_RANGE_UV 625000
>-#define VADC_RATIOMETRIC_RANGE_UV 1800000
>+#define VADC_RATIOMETRIC_RANGE 1800
>
> #define VADC_DEF_PRESCALING 0 /* 1:1 */
> #define VADC_DEF_DECIMATION 0 /* 512 */
>@@ -92,6 +92,8 @@
> #define VADC_DEF_AVG_SAMPLES 0 /* 1 sample */
> #define VADC_DEF_CALIB_TYPE VADC_CALIB_ABSOLUTE
>
>+#define VADC_DEF_SCALE_FN SCALE_DEFAULT
>+
> #define VADC_DECIMATION_MIN 512
> #define VADC_DECIMATION_MAX 4096
>
>@@ -100,9 +102,43 @@
>
> #define KELVINMIL_CELSIUSMIL 273150
>
>+#define PMI_CHG_SCALE_1 -138890
>+#define PMI_CHG_SCALE_2 391750000000
>+
> #define VADC_CHAN_MIN VADC_USBIN
> #define VADC_CHAN_MAX VADC_LR_MUX3_BUF_PU1_PU2_XO_THERM
>
>+/**
>+ * enum vadc_scale_fn_type - Scaling function to convert ADC code to
>+ * physical scaled units for the channel.
>+ * %SCALE_DEFAULT: Default scaling to convert raw adc code to voltage (uV).
>+ * %SCALE_THERM_100K_PULLUP: Returns temperature in millidegC.
>+ * Uses a mapping table with 100K pullup.
>+ * %SCALE_PMIC_THERM: Returns result in milli degree's Centigrade.
>+ * %SCALE_XOTHERM: Returns XO thermistor voltage in millidegC.
>+ * %SCALE_PMI_CHG_TEMP: Conversion for PMI CHG temp
>+ * %SCALE_NONE: Do not use this scaling type.
>+ */
>+enum vadc_scale_fn_type {
>+ SCALE_DEFAULT = 0,
>+ SCALE_THERM_100K_PULLUP,
>+ SCALE_PMIC_THERM,
>+ SCALE_XOTHERM,
>+ SCALE_PMI_CHG_TEMP,
>+ SCALE_NONE,
>+};
>+
>+/**
>+ * struct vadc_map_pt - Map the graph representation for ADC channel
>+ * @x: Represent the ADC digitized code.
>+ * @y: Represent the physical data which can be temperature, voltage,
>+ * resistance.
>+ */
>+struct vadc_map_pt {
>+ s32 x;
>+ s32 y;
>+};
>+
> /*
> * VADC_CALIB_ABSOLUTE: uses the 625mV and 1.25V as reference channels.
> * VADC_CALIB_RATIOMETRIC: uses the reference voltage (1.8V) and GND for
>@@ -148,6 +184,9 @@ struct vadc_prescale_ratio {
> * start of conversion.
> * @avg_samples: ability to provide single result from the ADC
> * that is an average of multiple measurements.
>+ *@scale_function: Represents the scaling function to convert voltage
>+ * physical units desired by the client for the channel.
>+ * Referenced from enum vadc_scale_fn_type.
> */
> struct vadc_channel_prop {
> unsigned int channel;
>@@ -156,6 +195,7 @@ struct vadc_channel_prop {
> unsigned int prescale;
> unsigned int hw_settle_time;
> unsigned int avg_samples;
>+ unsigned int scale_function;
> };
>
> /**
>@@ -197,6 +237,44 @@ struct vadc_priv {
> {.num = 1, .den = 10}
> };
>
>+/* Voltage to temperature */
>+static const struct vadc_map_pt adcmap_100k_104ef_104fb[] = {
>+ {1758, -40},
>+ {1742, -35},
>+ {1719, -30},
>+ {1691, -25},
>+ {1654, -20},
>+ {1608, -15},
>+ {1551, -10},
>+ {1483, -5},
>+ {1404, 0},
>+ {1315, 5},
>+ {1218, 10},
>+ {1114, 15},
>+ {1007, 20},
>+ {900, 25},
>+ {795, 30},
>+ {696, 35},
>+ {605, 40},
>+ {522, 45},
>+ {448, 50},
>+ {383, 55},
>+ {327, 60},
>+ {278, 65},
>+ {237, 70},
>+ {202, 75},
>+ {172, 80},
>+ {146, 85},
>+ {125, 90},
>+ {107, 95},
>+ {92, 100},
>+ {79, 105},
>+ {68, 110},
>+ {59, 115},
>+ {51, 120},
>+ {44, 125}
>+};
>+
> static int vadc_read(struct vadc_priv *vadc, u16 offset, u8 *data)
> {
> return regmap_bulk_read(vadc->regmap, vadc->base + offset, data, 1);
>@@ -418,7 +496,7 @@ static int vadc_measure_ref_points(struct vadc_priv *vadc)
> u16 read_1, read_2;
> int ret;
>
>- vadc->graph[VADC_CALIB_RATIOMETRIC].dx = VADC_RATIOMETRIC_RANGE_UV;
>+ vadc->graph[VADC_CALIB_RATIOMETRIC].dx = VADC_RATIOMETRIC_RANGE;
> vadc->graph[VADC_CALIB_ABSOLUTE].dx = VADC_ABSOLUTE_RANGE_UV;
>
> prop = vadc_get_channel(vadc, VADC_REF_1250MV);
>@@ -468,27 +546,128 @@ static int vadc_measure_ref_points(struct vadc_priv *vadc)
> return ret;
> }
>
>-static s32 vadc_calibrate(struct vadc_priv *vadc,
>- const struct vadc_channel_prop *prop, u16 adc_code)
>+static int vadc_map_voltage_temp(const struct vadc_map_pt *pts,
>+ u32 tablesize, s32 input, s64 *output)
> {
>- const struct vadc_prescale_ratio *prescale;
>- s64 voltage;
>+ bool descending = 1;
>+ u32 i = 0;
>+
>+ if (!pts)
>+ return -EINVAL;
>+
>+ /* Check if table is descending or ascending */
>+ if (tablesize > 1) {
>+ if (pts[0].x < pts[1].x)
>+ descending = 0;
>+ }
>+
>+ while (i < tablesize) {
>+ if ((descending == 1) && (pts[i].x < input)) {

Just if (descending) instead of (descending == 1) and so on for the below as well

>+ /* table entry is less than measured*/
>+ /* value and table is descending, stop */
>+ break;
>+ } else if ((descending == 0) &&
>+ (pts[i].x > input)) {
>+ /* table entry is greater than measured*/
>+ /*value and table is ascending, stop */
>+ break;
>+ }
>+ i++;
>+ }
>+
>+ if (i == 0) {
>+ *output = pts[0].y;
>+ } else if (i == tablesize) {
>+ *output = pts[tablesize - 1].y;
>+ } else {
>+ /* result is between search_index and search_index-1 */
>+ /* interpolate linearly */
>+ *output = (((s32)((pts[i].y - pts[i - 1].y) *
>+ (input - pts[i - 1].x)) /
>+ (pts[i].x - pts[i - 1].x)) +
>+ pts[i - 1].y);
>+ }

hmm, so for descending, input - pts[i -1].x is negative and
we are adding that to pts[i-1].y, is that correct ?
>
>- voltage = adc_code - vadc->graph[prop->calibration].gnd;
>- voltage *= vadc->graph[prop->calibration].dx;
>- voltage = div64_s64(voltage, vadc->graph[prop->calibration].dy);
>+ return 0;
>+}
>
>+static void vadc_scale_calib(struct vadc_priv *vadc, u16 adc_code,
>+ const struct vadc_channel_prop *prop,
>+ s64 *scale_voltage)
>+{
>+ *scale_voltage = (adc_code -
>+ vadc->graph[prop->calibration].gnd);
>+ *scale_voltage *= vadc->graph[prop->calibration].dx;
>+ *scale_voltage = div64_s64(*scale_voltage,
>+ vadc->graph[prop->calibration].dy);
> if (prop->calibration == VADC_CALIB_ABSOLUTE)
>- voltage += vadc->graph[prop->calibration].dx;
>+ *scale_voltage +=
>+ vadc->graph[prop->calibration].dx;
>
>- if (voltage < 0)
>- voltage = 0;
>+ if (*scale_voltage < 0)
>+ *scale_voltage = 0;
>+}
>
>- prescale = &vadc_prescale_ratios[prop->prescale];
>+static s64 vadc_scale_fn(struct vadc_priv *vadc,
>+ const struct vadc_channel_prop *prop, u16 adc_code)
>+{
>+ const struct vadc_prescale_ratio *prescale;
>+ s64 voltage = 0, result = 0;
>+ int ret;
>
>- voltage = voltage * prescale->den;
>+ switch (prop->scale_function) {
>
>- return div64_s64(voltage, prescale->num);
>+ case SCALE_DEFAULT:
>+ vadc_scale_calib(vadc, adc_code, prop, &voltage);
>+
>+ prescale = &vadc_prescale_ratios[prop->prescale];
>+ voltage = voltage * prescale->den;
>+ return div64_s64(voltage, prescale->num);
>+

This is the default case that exists today. So the code rearrange for making
the vadc_scale_calib common can be introduced in one patch and the
rest of the below new scaling functions in subsequent patches.


>+ case SCALE_THERM_100K_PULLUP:
>+ case SCALE_XOTHERM:
>+ vadc_scale_calib(vadc, adc_code, prop, &voltage);
>+
>+ if (prop->calibration == VADC_CALIB_ABSOLUTE)
>+ do_div(voltage, 1000);
>+
>+ vadc_map_voltage_temp(adcmap_100k_104ef_104fb,
>+ ARRAY_SIZE(adcmap_100k_104ef_104fb),
>+ voltage, &result);
>+ result *= 1000;
>+ return result;
>+
>+ case SCALE_PMIC_THERM:
>+ vadc_scale_calib(vadc, adc_code, prop, &voltage);
>+
>+ if (voltage > 0) {
>+ prescale = &vadc_prescale_ratios[prop->prescale];
>+ voltage = voltage * prescale->den;
>+ do_div(voltage, prescale->num * 2);
>+ } else {
>+ voltage = 0;
>+ }
>+
>+ voltage -= KELVINMIL_CELSIUSMIL;
>+
>+ return voltage;
>+
>+ case SCALE_PMI_CHG_TEMP:
>+ vadc_scale_calib(vadc, adc_code, prop, &voltage);
>+ prescale = &vadc_prescale_ratios[prop->prescale];
>+ voltage = voltage * prescale->den;
>+
>+ voltage = div64_s64(voltage, prescale->num);
>+ voltage = ((PMI_CHG_SCALE_1) * (voltage * 2));
>+ voltage = (voltage + PMI_CHG_SCALE_2);
>+ return div64_s64(voltage, 1000000);
>+
>+ default:
>+ ret = -EINVAL;
>+ break;
>+ }
>+
>+ return ret;
> }
>
> static int vadc_decimation_from_dt(u32 value)
>@@ -552,11 +731,8 @@ static int vadc_read_raw(struct iio_dev *indio_dev,
> if (ret)
> break;
>
>- *val = vadc_calibrate(vadc, prop, adc_code);
>+ *val = vadc_scale_fn(vadc, prop, adc_code);
>
>- /* 2mV/K, return milli Celsius */
>- *val /= 2;
>- *val -= KELVINMIL_CELSIUSMIL;
> return IIO_VAL_INT;
> case IIO_CHAN_INFO_RAW:
> prop = &vadc->chan_props[chan->address];
>@@ -564,12 +740,8 @@ static int vadc_read_raw(struct iio_dev *indio_dev,
> if (ret)
> break;
>
>- *val = vadc_calibrate(vadc, prop, adc_code);
>+ *val = (int)adc_code;
> return IIO_VAL_INT;
>- case IIO_CHAN_INFO_SCALE:
>- *val = 0;
>- *val2 = 1000;
>- return IIO_VAL_INT_PLUS_MICRO;
> default:
> ret = -EINVAL;
> break;
>@@ -613,11 +785,13 @@ struct vadc_channels {
> }, \
>
> #define VADC_CHAN_TEMP(_dname, _pre) \
>- VADC_CHAN(_dname, IIO_TEMP, BIT(IIO_CHAN_INFO_PROCESSED), _pre) \
>+ VADC_CHAN(_dname, IIO_TEMP, \
>+ BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_PROCESSED), \
>+ _pre) \
>
> #define VADC_CHAN_VOLT(_dname, _pre) \
>- VADC_CHAN(_dname, IIO_VOLTAGE, \
>- BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), \
>+ VADC_CHAN(_dname, IIO_VOLTAGE, \
>+ BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_PROCESSED),\
> _pre) \
>
For this and the below changes to VADC_CHAN_VOLT to TEMP, why is that done ?
Now both macros are setting the same flags.

> /*
>@@ -637,12 +811,11 @@ struct vadc_channels {
> VADC_CHAN_TEMP(DIE_TEMP, 0)
> VADC_CHAN_VOLT(REF_625MV, 0)
> VADC_CHAN_VOLT(REF_1250MV, 0)
>- VADC_CHAN_VOLT(CHG_TEMP, 0)
>+ VADC_CHAN_TEMP(CHG_TEMP, 0)
> VADC_CHAN_VOLT(SPARE1, 0)
> VADC_CHAN_VOLT(SPARE2, 0)
> VADC_CHAN_VOLT(GND_REF, 0)
> VADC_CHAN_VOLT(VDD_VADC, 0)
>-
> VADC_CHAN_VOLT(P_MUX1_1_1, 0)
> VADC_CHAN_VOLT(P_MUX2_1_1, 0)
> VADC_CHAN_VOLT(P_MUX3_1_1, 0)
>@@ -659,7 +832,6 @@ struct vadc_channels {
> VADC_CHAN_VOLT(P_MUX14_1_1, 0)
> VADC_CHAN_VOLT(P_MUX15_1_1, 0)
> VADC_CHAN_VOLT(P_MUX16_1_1, 0)
>-
> VADC_CHAN_VOLT(P_MUX1_1_3, 1)
> VADC_CHAN_VOLT(P_MUX2_1_3, 1)
> VADC_CHAN_VOLT(P_MUX3_1_3, 1)
>@@ -676,7 +848,6 @@ struct vadc_channels {
> VADC_CHAN_VOLT(P_MUX14_1_3, 1)
> VADC_CHAN_VOLT(P_MUX15_1_3, 1)
> VADC_CHAN_VOLT(P_MUX16_1_3, 1)
>-
> VADC_CHAN_VOLT(LR_MUX1_BAT_THERM, 0)
> VADC_CHAN_VOLT(LR_MUX2_BAT_ID, 0)
> VADC_CHAN_VOLT(LR_MUX3_XO_THERM, 0)
>@@ -690,42 +861,40 @@ struct vadc_channels {
> VADC_CHAN_VOLT(AMUX_PU1, 0)
> VADC_CHAN_VOLT(AMUX_PU2, 0)
> VADC_CHAN_VOLT(LR_MUX3_BUF_XO_THERM, 0)
>-
>- VADC_CHAN_VOLT(LR_MUX1_PU1_BAT_THERM, 0)
>+ VADC_CHAN_TEMP(LR_MUX1_PU1_BAT_THERM, 0)
> VADC_CHAN_VOLT(LR_MUX2_PU1_BAT_ID, 0)
>- VADC_CHAN_VOLT(LR_MUX3_PU1_XO_THERM, 0)
>- VADC_CHAN_VOLT(LR_MUX4_PU1_AMUX_THM1, 0)
>- VADC_CHAN_VOLT(LR_MUX5_PU1_AMUX_THM2, 0)
>- VADC_CHAN_VOLT(LR_MUX6_PU1_AMUX_THM3, 0)
>+ VADC_CHAN_TEMP(LR_MUX3_PU1_XO_THERM, 0)
>+ VADC_CHAN_TEMP(LR_MUX4_PU1_AMUX_THM1, 0)
>+ VADC_CHAN_TEMP(LR_MUX5_PU1_AMUX_THM2, 0)
>+ VADC_CHAN_TEMP(LR_MUX6_PU1_AMUX_THM3, 0)
> VADC_CHAN_VOLT(LR_MUX7_PU1_AMUX_HW_ID, 0)
>- VADC_CHAN_VOLT(LR_MUX8_PU1_AMUX_THM4, 0)
>- VADC_CHAN_VOLT(LR_MUX9_PU1_AMUX_THM5, 0)
>+ VADC_CHAN_TEMP(LR_MUX8_PU1_AMUX_THM4, 0)
>+ VADC_CHAN_TEMP(LR_MUX9_PU1_AMUX_THM5, 0)
> VADC_CHAN_VOLT(LR_MUX10_PU1_AMUX_USB_ID, 0)
>- VADC_CHAN_VOLT(LR_MUX3_BUF_PU1_XO_THERM, 0)
>-
>- VADC_CHAN_VOLT(LR_MUX1_PU2_BAT_THERM, 0)
>+ VADC_CHAN_TEMP(LR_MUX3_BUF_PU1_XO_THERM, 0)
>+ VADC_CHAN_TEMP(LR_MUX1_PU2_BAT_THERM, 0)
> VADC_CHAN_VOLT(LR_MUX2_PU2_BAT_ID, 0)
>- VADC_CHAN_VOLT(LR_MUX3_PU2_XO_THERM, 0)
>- VADC_CHAN_VOLT(LR_MUX4_PU2_AMUX_THM1, 0)
>- VADC_CHAN_VOLT(LR_MUX5_PU2_AMUX_THM2, 0)
>- VADC_CHAN_VOLT(LR_MUX6_PU2_AMUX_THM3, 0)
>+ VADC_CHAN_TEMP(LR_MUX3_PU2_XO_THERM, 0)
>+ VADC_CHAN_TEMP(LR_MUX4_PU2_AMUX_THM1, 0)
>+ VADC_CHAN_TEMP(LR_MUX5_PU2_AMUX_THM2, 0)
>+ VADC_CHAN_TEMP(LR_MUX6_PU2_AMUX_THM3, 0)
> VADC_CHAN_VOLT(LR_MUX7_PU2_AMUX_HW_ID, 0)
>- VADC_CHAN_VOLT(LR_MUX8_PU2_AMUX_THM4, 0)
>- VADC_CHAN_VOLT(LR_MUX9_PU2_AMUX_THM5, 0)
>+ VADC_CHAN_TEMP(LR_MUX8_PU2_AMUX_THM4, 0)
>+ VADC_CHAN_TEMP(LR_MUX9_PU2_AMUX_THM5, 0)
> VADC_CHAN_VOLT(LR_MUX10_PU2_AMUX_USB_ID, 0)
>- VADC_CHAN_VOLT(LR_MUX3_BUF_PU2_XO_THERM, 0)
>-
>- VADC_CHAN_VOLT(LR_MUX1_PU1_PU2_BAT_THERM, 0)
>+ VADC_CHAN_TEMP(LR_MUX3_BUF_PU2_XO_THERM, 0)
>+ VADC_CHAN_TEMP(LR_MUX1_PU1_PU2_BAT_THERM, 0)
> VADC_CHAN_VOLT(LR_MUX2_PU1_PU2_BAT_ID, 0)
>- VADC_CHAN_VOLT(LR_MUX3_PU1_PU2_XO_THERM, 0)
>- VADC_CHAN_VOLT(LR_MUX4_PU1_PU2_AMUX_THM1, 0)
>- VADC_CHAN_VOLT(LR_MUX5_PU1_PU2_AMUX_THM2, 0)
>- VADC_CHAN_VOLT(LR_MUX6_PU1_PU2_AMUX_THM3, 0)
>+ VADC_CHAN_TEMP(LR_MUX3_PU1_PU2_XO_THERM, 0)
>+ VADC_CHAN_TEMP(LR_MUX4_PU1_PU2_AMUX_THM1, 0)
>+ VADC_CHAN_TEMP(LR_MUX5_PU1_PU2_AMUX_THM2, 0)
>+ VADC_CHAN_TEMP(LR_MUX6_PU1_PU2_AMUX_THM3, 0)
> VADC_CHAN_VOLT(LR_MUX7_PU1_PU2_AMUX_HW_ID, 0)
>- VADC_CHAN_VOLT(LR_MUX8_PU1_PU2_AMUX_THM4, 0)
>- VADC_CHAN_VOLT(LR_MUX9_PU1_PU2_AMUX_THM5, 0)
>+ VADC_CHAN_TEMP(LR_MUX8_PU1_PU2_AMUX_THM4, 0)
>+ VADC_CHAN_TEMP(LR_MUX9_PU1_PU2_AMUX_THM5, 0)
> VADC_CHAN_VOLT(LR_MUX10_PU1_PU2_AMUX_USB_ID, 0)
>- VADC_CHAN_VOLT(LR_MUX3_BUF_PU1_PU2_XO_THERM, 0)
>+ VADC_CHAN_TEMP(LR_MUX3_BUF_PU1_PU2_XO_THERM, 0)
>+
> };
>
> static int vadc_get_dt_channel_data(struct device *dev,
>@@ -802,6 +971,11 @@ static int vadc_get_dt_channel_data(struct device *dev,
> prop->avg_samples = VADC_DEF_AVG_SAMPLES;
> }
>
>+ ret = of_property_read_u32(node, "qcom,scale-function",
>+ &prop->scale_function);
>+ if (ret)
>+ prop->scale_function = SCALE_DEFAULT;
>+


Is this a new binding, in that case the documentation has to be updated for this and
probably introduce this in one first patch and more patches for the rest of the changes.

> if (of_property_read_bool(node, "qcom,ratiometric"))
> prop->calibration = VADC_CALIB_RATIOMETRIC;
> else
>@@ -850,9 +1024,9 @@ static int vadc_get_dt_data(struct vadc_priv *vadc, struct device_node *node)
>
> iio_chan->channel = prop.channel;
> iio_chan->datasheet_name = vadc_chan->datasheet_name;
>+ iio_chan->extend_name = child->name;
> iio_chan->info_mask_separate = vadc_chan->info_mask;
> iio_chan->type = vadc_chan->type;
>- iio_chan->indexed = 1;
> iio_chan->address = index++;
>
> iio_chan++;
>@@ -964,16 +1138,21 @@ static int vadc_probe(struct platform_device *pdev)
> if (ret)
> return ret;
>
>- irq_eoc = platform_get_irq(pdev, 0);
>- if (irq_eoc < 0) {
>- if (irq_eoc == -EPROBE_DEFER || irq_eoc == -EINVAL)
>- return irq_eoc;
>- vadc->poll_eoc = true;
>- } else {
>- ret = devm_request_irq(dev, irq_eoc, vadc_isr, 0,
>- "spmi-vadc", vadc);
>- if (ret)
>- return ret;
>+ vadc->poll_eoc = of_property_read_bool(node,
>+ "qcom,vadc-poll-eoc");
>+

Same comment as above for introducing the new binding and the reason
for that.

>+ if (!vadc->poll_eoc) {
>+ irq_eoc = platform_get_irq(pdev, 0);
>+ if (irq_eoc < 0) {
>+ if (irq_eoc == -EPROBE_DEFER || irq_eoc == -EINVAL)
>+ return irq_eoc;
>+ vadc->poll_eoc = true;
>+ } else {
>+ ret = devm_request_irq(dev, irq_eoc, vadc_isr, 0,
>+ "spmi-vadc", vadc);
>+ if (ret)
>+ return ret;
>+ }
> }
>
> ret = vadc_reset(vadc);

Regards,
Sricharan