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

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

[Rama Krishna Phani A]

Add changes to support different scale functions to convert adc code to
physical units.

Signed-off-by: Rama Krishna Phani A <rphani@codeaurora.org>
---
 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)) {
+			/* 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);
+	}
 
-	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);
+
+	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)							\
 
 /*
@@ -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;
+
 	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");
+
+	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);
-- 
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a Linux Foundation Collaborative Project

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

[Sricharan]

Hi Ramakrishna,

>Add changes to support different scale functions to convert adc code to
>physical units.
>
>Signed-off-by: Rama Krishna Phani A <rphani@codeaurora.org>
>---
> 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

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

[Phani A, Rama Krishna]

Hi Sricharan,

Will incorporate the suggested changes in the next patch set.

On 25-Oct-16 6:39 PM, Sricharan wrote:
> Hi Ramakrishna,
>
>> Add changes to support different scale functions to convert adc code to
>> physical units.
>>
>> Signed-off-by: Rama Krishna Phani A <rphani@codeaurora.org>
>> ---
>> 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

	Will change in next patch.

>
>> +			/* 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 ?

		The formula used is to interpolate between two points 	using linear 
interpolation.
>>
>> -	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.
	
	Will change in next patch.
>
>
>> +	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.

	For Voltage channels IIO_VOLTAGE is needed where as for Temperature 
channels IIO_TEMP is needed.
	
>
>> /*
>> @@ -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.

	Yes ., its a new binding. Will change in next patch.
>
>> 	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.

	Yes ., its a new binding. Will change in next patch.
>
>> +	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
>

Thanks,
Ramakrishna

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

[Sricharan]

Hi Ramakrishna,

[snip..]

>>> +	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
>
>	Will change in next patch.
>
>>
>>> +			/* 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 ?
>
>		The formula used is to interpolate between two points 	using linear
>interpolation.

 Right, agree. my question can be ignored.

[snip..]

>>> #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.
>
>	For Voltage channels IIO_VOLTAGE is needed where as for Temperature
>channels IIO_TEMP is needed.
>
>>
>>> /*
>>> @@ -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)
>>> -

And also looks like the deletion of these and below 
new lines are unnecessary ?

Regards,
 Sricharan

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

[Phani A, Rama Krishna]

Hi Sricharan,

On 26-Oct-16 3:47 PM, Sricharan wrote:
> Hi Ramakrishna,
>
> [snip..]
>
>>>> +	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
>>
>> 	Will change in next patch.
>>
>>>
>>>> +			/* 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 ?
>>
>> 		The formula used is to interpolate between two points 	using linear
>> interpolation.
>
>  Right, agree. my question can be ignored.
>
> [snip..]
>
>>>> #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.
>>
>> 	For Voltage channels IIO_VOLTAGE is needed where as for Temperature
>> channels IIO_TEMP is needed.
>>
>>>
>>>> /*
>>>> @@ -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)
>>>> -
>
> And also looks like the deletion of these and below
> new lines are unnecessary ?

Agree, Will retain these new lines in next patch V2.
>
> Regards,
>  Sricharan
>

Thanks,
Ramakrishna

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

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 2084 bytes --]

Hi Rama,

[auto build test WARNING on iio/togreg]
[also build test WARNING on v4.9-rc3 next-20161028]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Rama-Krishna-Phani-A/iio-adc-spmi-vadc-Changes-to-support-different-scaling/20161025-141253
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
config: openrisc-allmodconfig (attached as .config)
compiler: or32-linux-gcc (GCC) 4.5.1-or32-1.0rc1
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=openrisc 

All warnings (new ones prefixed by >>):

   drivers/iio/adc/qcom-spmi-vadc.c: In function 'vadc_scale_fn':
>> drivers/iio/adc/qcom-spmi-vadc.c:632:4: warning: comparison of distinct pointer types lacks a cast
   drivers/iio/adc/qcom-spmi-vadc.c:646:4: warning: comparison of distinct pointer types lacks a cast

vim +632 drivers/iio/adc/qcom-spmi-vadc.c

   616		int ret;
   617	
   618		switch (prop->scale_function) {
   619	
   620		case SCALE_DEFAULT:
   621			vadc_scale_calib(vadc, adc_code, prop, &voltage);
   622	
   623			prescale = &vadc_prescale_ratios[prop->prescale];
   624			voltage = voltage * prescale->den;
   625			return div64_s64(voltage, prescale->num);
   626	
   627		case SCALE_THERM_100K_PULLUP:
   628		case SCALE_XOTHERM:
   629			vadc_scale_calib(vadc, adc_code, prop, &voltage);
   630	
   631			if (prop->calibration == VADC_CALIB_ABSOLUTE)
 > 632				do_div(voltage, 1000);
   633	
   634			vadc_map_voltage_temp(adcmap_100k_104ef_104fb,
   635					      ARRAY_SIZE(adcmap_100k_104ef_104fb),
   636					      voltage, &result);
   637			result *= 1000;
   638			return result;
   639	
   640		case SCALE_PMIC_THERM:

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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