[PATCH v1 1/5] math.h: Introduce data types for fractional numbers

[PATCH v1 1/5] math.h: Introduce data types for fractional numbers

[Andy Shevchenko]

Introduce a macro to produce data types like

	struct TYPE_fract {
		__TYPE numerator;
		__TYPE denominator;
	};

to be used in the code wherever it's needed.

In the following changes convert some users to it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---

May be pulled via IIO tree.

 include/linux/math.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/math.h b/include/linux/math.h
index 53674a327e39..439b8f0b9ebd 100644
--- a/include/linux/math.h
+++ b/include/linux/math.h
@@ -2,6 +2,7 @@
 #ifndef _LINUX_MATH_H
 #define _LINUX_MATH_H
 
+#include <linux/types.h>
 #include <asm/div64.h>
 #include <uapi/linux/kernel.h>
 
@@ -106,6 +107,17 @@
 }							\
 )
 
+#define __STRUCT_FRACT(type)				\
+struct type##_fract {					\
+	__##type numerator;				\
+	__##type denominator;				\
+};
+__STRUCT_FRACT(s16)
+__STRUCT_FRACT(u16)
+__STRUCT_FRACT(s32)
+__STRUCT_FRACT(u32)
+#undef __STRUCT_FRACT
+
 /*
  * Multiplies an integer by a fraction, while avoiding unnecessary
  * overflow or loss of precision.
-- 
2.34.1

[PATCH v1 2/5] iio: adc: rn5t618: Re-use generic struct u16_fract

[Andy Shevchenko]

Instead of custom data type re-use generic struct u16_fract.
No changes intended.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/iio/adc/rn5t618-adc.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/drivers/iio/adc/rn5t618-adc.c b/drivers/iio/adc/rn5t618-adc.c
index 7d891b4ea461..6bf32907f01d 100644
--- a/drivers/iio/adc/rn5t618-adc.c
+++ b/drivers/iio/adc/rn5t618-adc.c
@@ -42,11 +42,6 @@ struct rn5t618_adc_data {
 	int irq;
 };
 
-struct rn5t618_channel_ratios {
-	u16 numerator;
-	u16 denominator;
-};
-
 enum rn5t618_channels {
 	LIMMON = 0,
 	VBAT,
@@ -58,7 +53,7 @@ enum rn5t618_channels {
 	AIN0
 };
 
-static const struct rn5t618_channel_ratios rn5t618_ratios[8] = {
+static const struct u16_fract rn5t618_ratios[8] = {
 	[LIMMON] = {50, 32}, /* measured across 20mOhm, amplified by 32 */
 	[VBAT] = {2, 1},
 	[VADP] = {3, 1},
-- 
2.34.1

[PATCH v1 3/5] iio: adc: twl4030-madc: Re-use generic struct s16_fract

[Andy Shevchenko]

Instead of custom data type re-use generic struct s16_fract.
No changes intended.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/iio/adc/twl4030-madc.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/drivers/iio/adc/twl4030-madc.c b/drivers/iio/adc/twl4030-madc.c
index 6ce40cc4568a..f8f8aea15612 100644
--- a/drivers/iio/adc/twl4030-madc.c
+++ b/drivers/iio/adc/twl4030-madc.c
@@ -231,13 +231,7 @@ static const struct iio_chan_spec twl4030_madc_iio_channels[] = {
 
 static struct twl4030_madc_data *twl4030_madc;
 
-struct twl4030_prescale_divider_ratios {
-	s16 numerator;
-	s16 denominator;
-};
-
-static const struct twl4030_prescale_divider_ratios
-twl4030_divider_ratios[16] = {
+static const struct s16_fract twl4030_divider_ratios[16] = {
 	{1, 1},		/* CHANNEL 0 No Prescaler */
 	{1, 1},		/* CHANNEL 1 No Prescaler */
 	{6, 10},	/* CHANNEL 2 */
@@ -256,7 +250,6 @@ twl4030_divider_ratios[16] = {
 	{5, 11},	/* CHANNEL 15 */
 };
 
-
 /* Conversion table from -3 to 55 degrees Celcius */
 static int twl4030_therm_tbl[] = {
 	30800,	29500,	28300,	27100,
-- 
2.34.1

[PATCH v1 4/5] iio: adc: qcom-vadc-common: Re-use generic struct u32_fract

[Andy Shevchenko]

Instead of custom data type re-use generic struct u32_fract.
No changes intended.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/iio/adc/qcom-pm8xxx-xoadc.c      |  2 +-
 drivers/iio/adc/qcom-spmi-vadc.c         |  2 +-
 drivers/iio/adc/qcom-vadc-common.c       | 48 ++++++++++++------------
 include/linux/iio/adc/qcom-vadc-common.h | 15 ++------
 4 files changed, 29 insertions(+), 38 deletions(-)

diff --git a/drivers/iio/adc/qcom-pm8xxx-xoadc.c b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
index 21d7eff645c3..ef249d745d85 100644
--- a/drivers/iio/adc/qcom-pm8xxx-xoadc.c
+++ b/drivers/iio/adc/qcom-pm8xxx-xoadc.c
@@ -175,7 +175,7 @@ struct xoadc_channel {
 	const char *datasheet_name;
 	u8 pre_scale_mux:2;
 	u8 amux_channel:4;
-	const struct vadc_prescale_ratio prescale;
+	const struct u32_fract prescale;
 	enum iio_chan_type type;
 	enum vadc_scale_fn_type scale_fn_type;
 	u8 amux_ip_rsv:3;
diff --git a/drivers/iio/adc/qcom-spmi-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c
index 07b1a99381d9..69733564fa42 100644
--- a/drivers/iio/adc/qcom-spmi-vadc.c
+++ b/drivers/iio/adc/qcom-spmi-vadc.c
@@ -122,7 +122,7 @@ struct vadc_priv {
 	struct mutex		 lock;
 };
 
-static const struct vadc_prescale_ratio vadc_prescale_ratios[] = {
+static const struct u32_fract vadc_prescale_ratios[] = {
 	{.num =  1, .den =  1},
 	{.num =  1, .den =  3},
 	{.num =  1, .den =  4},
diff --git a/drivers/iio/adc/qcom-vadc-common.c b/drivers/iio/adc/qcom-vadc-common.c
index 14723896aab2..ec177360a354 100644
--- a/drivers/iio/adc/qcom-vadc-common.c
+++ b/drivers/iio/adc/qcom-vadc-common.c
@@ -289,7 +289,7 @@ static const struct vadc_map_pt adcmap7_100k[] = {
 	{ 2420, 130048 }
 };
 
-static const struct vadc_prescale_ratio adc5_prescale_ratios[] = {
+static const struct u32_fract adc5_prescale_ratios[] = {
 	{.num =  1, .den =  1},
 	{.num =  1, .den =  3},
 	{.num =  1, .den =  4},
@@ -302,31 +302,31 @@ static const struct vadc_prescale_ratio adc5_prescale_ratios[] = {
 };
 
 static int qcom_vadc_scale_hw_calib_volt(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_uv);
 static int qcom_vadc_scale_hw_calib_therm(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_mdec);
 static int qcom_vadc7_scale_hw_calib_therm(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_mdec);
 static int qcom_vadc_scale_hw_smb_temp(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_mdec);
 static int qcom_vadc_scale_hw_chg5_temp(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_mdec);
 static int qcom_vadc_scale_hw_calib_die_temp(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_mdec);
 static int qcom_vadc7_scale_hw_calib_die_temp(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_mdec);
 
@@ -406,7 +406,7 @@ static void qcom_vadc_scale_calib(const struct vadc_linear_graph *calib_graph,
 }
 
 static int qcom_vadc_scale_volt(const struct vadc_linear_graph *calib_graph,
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				bool absolute, u16 adc_code,
 				int *result_uv)
 {
@@ -422,7 +422,7 @@ static int qcom_vadc_scale_volt(const struct vadc_linear_graph *calib_graph,
 }
 
 static int qcom_vadc_scale_therm(const struct vadc_linear_graph *calib_graph,
-				 const struct vadc_prescale_ratio *prescale,
+				 const struct u32_fract *prescale,
 				 bool absolute, u16 adc_code,
 				 int *result_mdec)
 {
@@ -444,7 +444,7 @@ static int qcom_vadc_scale_therm(const struct vadc_linear_graph *calib_graph,
 }
 
 static int qcom_vadc_scale_die_temp(const struct vadc_linear_graph *calib_graph,
-				    const struct vadc_prescale_ratio *prescale,
+				    const struct u32_fract *prescale,
 				    bool absolute,
 				    u16 adc_code, int *result_mdec)
 {
@@ -467,7 +467,7 @@ static int qcom_vadc_scale_die_temp(const struct vadc_linear_graph *calib_graph,
 }
 
 static int qcom_vadc_scale_chg_temp(const struct vadc_linear_graph *calib_graph,
-				    const struct vadc_prescale_ratio *prescale,
+				    const struct u32_fract *prescale,
 				    bool absolute,
 				    u16 adc_code, int *result_mdec)
 {
@@ -487,7 +487,7 @@ static int qcom_vadc_scale_chg_temp(const struct vadc_linear_graph *calib_graph,
 
 /* convert voltage to ADC code, using 1.875V reference */
 static u16 qcom_vadc_scale_voltage_code(s32 voltage,
-					const struct vadc_prescale_ratio *prescale,
+					const struct u32_fract *prescale,
 					const u32 full_scale_code_volt,
 					unsigned int factor)
 {
@@ -501,7 +501,7 @@ static u16 qcom_vadc_scale_voltage_code(s32 voltage,
 }
 
 static int qcom_vadc_scale_code_voltage_factor(u16 adc_code,
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				unsigned int factor)
 {
@@ -531,7 +531,7 @@ static int qcom_vadc_scale_code_voltage_factor(u16 adc_code,
 }
 
 static int qcom_vadc7_scale_hw_calib_therm(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_mdec)
 {
@@ -557,7 +557,7 @@ static int qcom_vadc7_scale_hw_calib_therm(
 }
 
 static int qcom_vadc_scale_hw_calib_volt(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_uv)
 {
@@ -568,7 +568,7 @@ static int qcom_vadc_scale_hw_calib_volt(
 }
 
 static int qcom_vadc_scale_hw_calib_therm(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_mdec)
 {
@@ -584,7 +584,7 @@ static int qcom_vadc_scale_hw_calib_therm(
 }
 
 static int qcom_vadc_scale_hw_calib_die_temp(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_mdec)
 {
@@ -596,7 +596,7 @@ static int qcom_vadc_scale_hw_calib_die_temp(
 }
 
 static int qcom_vadc7_scale_hw_calib_die_temp(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_mdec)
 {
@@ -611,7 +611,7 @@ static int qcom_vadc7_scale_hw_calib_die_temp(
 }
 
 static int qcom_vadc_scale_hw_smb_temp(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_mdec)
 {
@@ -623,7 +623,7 @@ static int qcom_vadc_scale_hw_smb_temp(
 }
 
 static int qcom_vadc_scale_hw_chg5_temp(
-				const struct vadc_prescale_ratio *prescale,
+				const struct u32_fract *prescale,
 				const struct adc5_data *data,
 				u16 adc_code, int *result_mdec)
 {
@@ -636,7 +636,7 @@ static int qcom_vadc_scale_hw_chg5_temp(
 
 int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,
 		    const struct vadc_linear_graph *calib_graph,
-		    const struct vadc_prescale_ratio *prescale,
+		    const struct u32_fract *prescale,
 		    bool absolute,
 		    u16 adc_code, int *result)
 {
@@ -667,7 +667,7 @@ EXPORT_SYMBOL(qcom_vadc_scale);
 u16 qcom_adc_tm5_temp_volt_scale(unsigned int prescale_ratio,
 				 u32 full_scale_code_volt, int temp)
 {
-	const struct vadc_prescale_ratio *prescale = &adc5_prescale_ratios[prescale_ratio];
+	const struct u32_fract *prescale = &adc5_prescale_ratios[prescale_ratio];
 	s32 voltage;
 
 	voltage = qcom_vadc_map_temp_voltage(adcmap_100k_104ef_104fb_1875_vref,
@@ -682,7 +682,7 @@ int qcom_adc5_hw_scale(enum vadc_scale_fn_type scaletype,
 		    const struct adc5_data *data,
 		    u16 adc_code, int *result)
 {
-	const struct vadc_prescale_ratio *prescale = &adc5_prescale_ratios[prescale_ratio];
+	const struct u32_fract *prescale = &adc5_prescale_ratios[prescale_ratio];
 
 	if (!(scaletype >= SCALE_HW_CALIB_DEFAULT &&
 		scaletype < SCALE_HW_CALIB_INVALID)) {
diff --git a/include/linux/iio/adc/qcom-vadc-common.h b/include/linux/iio/adc/qcom-vadc-common.h
index 33f60f43e1aa..ce78d4804994 100644
--- a/include/linux/iio/adc/qcom-vadc-common.h
+++ b/include/linux/iio/adc/qcom-vadc-common.h
@@ -6,6 +6,7 @@
 #ifndef QCOM_VADC_COMMON_H
 #define QCOM_VADC_COMMON_H
 
+#include <linux/math.h>
 #include <linux/types.h>
 
 #define VADC_CONV_TIME_MIN_US			2000
@@ -79,16 +80,6 @@ struct vadc_linear_graph {
 	s32 gnd;
 };
 
-/**
- * struct vadc_prescale_ratio - Represent scaling ratio for ADC input.
- * @num: the inverse numerator of the gain applied to the input channel.
- * @den: the inverse denominator of the gain applied to the input channel.
- */
-struct vadc_prescale_ratio {
-	u32 num;
-	u32 den;
-};
-
 /**
  * enum vadc_scale_fn_type - Scaling function to convert ADC code to
  *				physical scaled units for the channel.
@@ -144,12 +135,12 @@ struct adc5_data {
 
 int qcom_vadc_scale(enum vadc_scale_fn_type scaletype,
 		    const struct vadc_linear_graph *calib_graph,
-		    const struct vadc_prescale_ratio *prescale,
+		    const struct u32_fract *prescale,
 		    bool absolute,
 		    u16 adc_code, int *result_mdec);
 
 struct qcom_adc5_scale_type {
-	int (*scale_fn)(const struct vadc_prescale_ratio *prescale,
+	int (*scale_fn)(const struct u32_fract *prescale,
 		const struct adc5_data *data, u16 adc_code, int *result);
 };
 
-- 
2.34.1

Re: [PATCH v1 4/5] iio: adc: qcom-vadc-common: Re-use generic struct u32_fract

[Andy Shevchenko]

On Mon, Jan 10, 2022 at 08:17:10PM +0200, Andy Shevchenko wrote:
> Instead of custom data type re-use generic struct u32_fract.
> No changes intended.

...

> -/**
> - * struct vadc_prescale_ratio - Represent scaling ratio for ADC input.
> - * @num: the inverse numerator of the gain applied to the input channel.
> - * @den: the inverse denominator of the gain applied to the input channel.
> - */
> -struct vadc_prescale_ratio {
> -	u32 num;
> -	u32 den;
> -};

Definitely forgot to compile this one.

-- 
With Best Regards,
Andy Shevchenko

[PATCH v1 5/5] iio: afe: iio-rescale: Re-use generic struct s32_fract

[Andy Shevchenko]

Instead of custom data type re-use generic struct s32_fract.
No changes intended.

The new member is put to be the first one to avoid additional
pointer arithmetic. Besides that one may switch to use fract
member to perform container_of(), which will be no-op in this
case, to get struct rescale.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---

I found this better in order how code is structurally (re)organized.
I may rebase this on top of ongoing AFE series.

Also reveals possibility to switch to rational best approximation.
But this is another story...

 drivers/iio/afe/iio-rescale.c | 74 +++++++++++++++++------------------
 1 file changed, 37 insertions(+), 37 deletions(-)

diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c
index 774eb3044edd..0368bca8a485 100644
--- a/drivers/iio/afe/iio-rescale.c
+++ b/drivers/iio/afe/iio-rescale.c
@@ -11,6 +11,7 @@
 #include <linux/gcd.h>
 #include <linux/iio/consumer.h>
 #include <linux/iio/iio.h>
+#include <linux/math.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
@@ -21,17 +22,16 @@ struct rescale;
 
 struct rescale_cfg {
 	enum iio_chan_type type;
-	int (*props)(struct device *dev, struct rescale *rescale);
+	int (*props)(struct device *dev, struct s32_fract *fract);
 };
 
 struct rescale {
+	struct s32_fract fract;
 	const struct rescale_cfg *cfg;
 	struct iio_channel *source;
 	struct iio_chan_spec chan;
 	struct iio_chan_spec_ext_info *ext_info;
 	bool chan_processed;
-	s32 numerator;
-	s32 denominator;
 };
 
 static int rescale_read_raw(struct iio_dev *indio_dev,
@@ -39,6 +39,7 @@ static int rescale_read_raw(struct iio_dev *indio_dev,
 			    int *val, int *val2, long mask)
 {
 	struct rescale *rescale = iio_priv(indio_dev);
+	struct s32_fract *fract = &rescale->fract;
 	unsigned long long tmp;
 	int ret;
 
@@ -67,19 +68,19 @@ static int rescale_read_raw(struct iio_dev *indio_dev,
 		}
 		switch (ret) {
 		case IIO_VAL_FRACTIONAL:
-			*val *= rescale->numerator;
-			*val2 *= rescale->denominator;
+			*val *= fract->numerator;
+			*val2 *= fract->denominator;
 			return ret;
 		case IIO_VAL_INT:
-			*val *= rescale->numerator;
-			if (rescale->denominator == 1)
+			*val *= fract->numerator;
+			if (fract->denominator == 1)
 				return ret;
-			*val2 = rescale->denominator;
+			*val2 = fract->denominator;
 			return IIO_VAL_FRACTIONAL;
 		case IIO_VAL_FRACTIONAL_LOG2:
 			tmp = *val * 1000000000LL;
-			do_div(tmp, rescale->denominator);
-			tmp *= rescale->numerator;
+			do_div(tmp, fract->denominator);
+			tmp *= fract->numerator;
 			do_div(tmp, 1000000000LL);
 			*val = tmp;
 			return ret;
@@ -175,7 +176,7 @@ static int rescale_configure_channel(struct device *dev,
 }
 
 static int rescale_current_sense_amplifier_props(struct device *dev,
-						 struct rescale *rescale)
+						 struct s32_fract *fract)
 {
 	u32 sense;
 	u32 gain_mult = 1;
@@ -199,22 +200,22 @@ static int rescale_current_sense_amplifier_props(struct device *dev,
 	 * numerator/denominator from overflowing.
 	 */
 	factor = gcd(sense, 1000000);
-	rescale->numerator = 1000000 / factor;
-	rescale->denominator = sense / factor;
+	fract->numerator = 1000000 / factor;
+	fract->denominator = sense / factor;
 
-	factor = gcd(rescale->numerator, gain_mult);
-	rescale->numerator /= factor;
-	rescale->denominator *= gain_mult / factor;
+	factor = gcd(fract->numerator, gain_mult);
+	fract->numerator /= factor;
+	fract->denominator *= gain_mult / factor;
 
-	factor = gcd(rescale->denominator, gain_div);
-	rescale->numerator *= gain_div / factor;
-	rescale->denominator /= factor;
+	factor = gcd(fract->denominator, gain_div);
+	fract->numerator *= gain_div / factor;
+	fract->denominator /= factor;
 
 	return 0;
 }
 
 static int rescale_current_sense_shunt_props(struct device *dev,
-					     struct rescale *rescale)
+					     struct s32_fract *fract)
 {
 	u32 shunt;
 	u32 factor;
@@ -228,35 +229,33 @@ static int rescale_current_sense_shunt_props(struct device *dev,
 	}
 
 	factor = gcd(shunt, 1000000);
-	rescale->numerator = 1000000 / factor;
-	rescale->denominator = shunt / factor;
+	fract->numerator = 1000000 / factor;
+	fract->denominator = shunt / factor;
 
 	return 0;
 }
 
 static int rescale_voltage_divider_props(struct device *dev,
-					 struct rescale *rescale)
+					 struct s32_fract *fract)
 {
 	int ret;
 	u32 factor;
 
-	ret = device_property_read_u32(dev, "output-ohms",
-				       &rescale->denominator);
+	ret = device_property_read_u32(dev, "output-ohms", &fract->denominator);
 	if (ret) {
 		dev_err(dev, "failed to read output-ohms: %d\n", ret);
 		return ret;
 	}
 
-	ret = device_property_read_u32(dev, "full-ohms",
-				       &rescale->numerator);
+	ret = device_property_read_u32(dev, "full-ohms", &fract->numerator);
 	if (ret) {
 		dev_err(dev, "failed to read full-ohms: %d\n", ret);
 		return ret;
 	}
 
-	factor = gcd(rescale->numerator, rescale->denominator);
-	rescale->numerator /= factor;
-	rescale->denominator /= factor;
+	factor = gcd(fract->numerator, fract->denominator);
+	fract->numerator /= factor;
+	fract->denominator /= factor;
 
 	return 0;
 }
@@ -299,6 +298,7 @@ static int rescale_probe(struct platform_device *pdev)
 	struct iio_dev *indio_dev;
 	struct iio_channel *source;
 	struct rescale *rescale;
+	struct s32_fract *fract;
 	int sizeof_ext_info;
 	int sizeof_priv;
 	int i;
@@ -322,24 +322,24 @@ static int rescale_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	rescale = iio_priv(indio_dev);
-
+	rescale->source = source;
 	rescale->cfg = of_device_get_match_data(dev);
-	rescale->numerator = 1;
-	rescale->denominator = 1;
 
-	ret = rescale->cfg->props(dev, rescale);
+	fract = &rescale->fract;
+	fract->numerator = 1;
+	fract->denominator = 1;
+
+	ret = rescale->cfg->props(dev, fract);
 	if (ret)
 		return ret;
 
-	if (!rescale->numerator || !rescale->denominator) {
+	if (!fract->numerator || !fract->denominator) {
 		dev_err(dev, "invalid scaling factor.\n");
 		return -EINVAL;
 	}
 
 	platform_set_drvdata(pdev, indio_dev);
 
-	rescale->source = source;
-
 	indio_dev->name = dev_name(dev);
 	indio_dev->info = &rescale_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
-- 
2.34.1