iio: light: STK3310: un-invert proximity values

In accordance with the recent proximity ABI changes,
STK3310's proximity readings should be un-inversed
in order to return low values for far-away objects
and high values for close ones.

As consequences of this change, iio event directions
have been switched and maximum proximity sensor
reference values have also been adjusted in accordance
with the real readings.
Signed-off-by: Tiberiu Breana <tiberiu.a.breana@intel.com>
Acked-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/light/stk3310.c

@@ -43,7 +43,6 @@
 #define STK3311_CHIP_ID_VAL			0x1D
 #define STK3310_PSINT_EN			0x01
 #define STK3310_PS_MAX_VAL			0xFFFF
-#define STK3310_THRESH_MAX			0xFFFF
 
 #define STK3310_DRIVER_NAME			"stk3310"
 #define STK3310_REGMAP_NAME			"stk3310_regmap"
@@ -84,15 +83,13 @@ static const struct reg_field stk3310_reg_field_flag_psint =
 				REG_FIELD(STK3310_REG_FLAG, 4, 4);
 static const struct reg_field stk3310_reg_field_flag_nf =
 				REG_FIELD(STK3310_REG_FLAG, 0, 0);
-/*
- * Maximum PS values with regard to scale. Used to export the 'inverse'
- * PS value (high values for far objects, low values for near objects).
- */
+
+/* Estimate maximum proximity values with regard to measurement scale. */
 static const int stk3310_ps_max[4] = {
-	STK3310_PS_MAX_VAL / 64,
-	STK3310_PS_MAX_VAL / 16,
-	STK3310_PS_MAX_VAL /  4,
-	STK3310_PS_MAX_VAL,
+	STK3310_PS_MAX_VAL / 640,
+	STK3310_PS_MAX_VAL / 160,
+	STK3310_PS_MAX_VAL /  40,
+	STK3310_PS_MAX_VAL /  10
 };
 
 static const int stk3310_scale_table[][2] = {
@@ -128,14 +125,14 @@ static const struct iio_event_spec stk3310_events[] = {
 	/* Proximity event */
 	{
 		.type = IIO_EV_TYPE_THRESH,
-		.dir = IIO_EV_DIR_FALLING,
+		.dir = IIO_EV_DIR_RISING,
 		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
 				 BIT(IIO_EV_INFO_ENABLE),
 	},
 	/* Out-of-proximity event */
 	{
 		.type = IIO_EV_TYPE_THRESH,
-		.dir = IIO_EV_DIR_RISING,
+		.dir = IIO_EV_DIR_FALLING,
 		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
 				 BIT(IIO_EV_INFO_ENABLE),
 	},
@@ -205,23 +202,16 @@ static int stk3310_read_event(struct iio_dev *indio_dev,
 	u8 reg;
 	u16 buf;
 	int ret;
-	unsigned int index;
 	struct stk3310_data *data = iio_priv(indio_dev);
 
 	if (info != IIO_EV_INFO_VALUE)
 		return -EINVAL;
 
-	/*
-	 * Only proximity interrupts are implemented at the moment.
-	 * Since we're inverting proximity values, the sensor's 'high'
-	 * threshold will become our 'low' threshold, associated with
-	 * 'near' events. Similarly, the sensor's 'low' threshold will
-	 * be our 'high' threshold, associated with 'far' events.
-	 */
+	/* Only proximity interrupts are implemented at the moment. */
 	if (dir == IIO_EV_DIR_RISING)
-		reg = STK3310_REG_THDL_PS;
-	else if (dir == IIO_EV_DIR_FALLING)
 		reg = STK3310_REG_THDH_PS;
+	else if (dir == IIO_EV_DIR_FALLING)
+		reg = STK3310_REG_THDL_PS;
 	else
 		return -EINVAL;
 
@@ -232,8 +222,7 @@ static int stk3310_read_event(struct iio_dev *indio_dev,
 		dev_err(&data->client->dev, "register read failed\n");
 		return ret;
 	}
-	regmap_field_read(data->reg_ps_gain, &index);
-	*val = swab16(stk3310_ps_max[index] - buf);
+	*val = swab16(buf);
 
 	return IIO_VAL_INT;
 }
@@ -257,13 +246,13 @@ static int stk3310_write_event(struct iio_dev *indio_dev,
 		return -EINVAL;
 
 	if (dir == IIO_EV_DIR_RISING)
-		reg = STK3310_REG_THDL_PS;
-	else if (dir == IIO_EV_DIR_FALLING)
 		reg = STK3310_REG_THDH_PS;
+	else if (dir == IIO_EV_DIR_FALLING)
+		reg = STK3310_REG_THDL_PS;
 	else
 		return -EINVAL;
 
-	buf = swab16(stk3310_ps_max[index] - val);
+	buf = swab16(val);
 	ret = regmap_bulk_write(data->regmap, reg, &buf, 2);
 	if (ret < 0)
 		dev_err(&client->dev, "failed to set PS threshold!\n");
@@ -334,14 +323,6 @@ static int stk3310_read_raw(struct iio_dev *indio_dev,
 			return ret;
 		}
 		*val = swab16(buf);
-		if (chan->type == IIO_PROXIMITY) {
-			/*
-			 * Invert the proximity data so we return low values
-			 * for close objects and high values for far ones.
-			 */
-			regmap_field_read(data->reg_ps_gain, &index);
-			*val = stk3310_ps_max[index] - *val;
-		}
 		mutex_unlock(&data->lock);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_INT_TIME:
@@ -581,8 +562,8 @@ static irqreturn_t stk3310_irq_event_handler(int irq, void *private)
 	}
 	event = IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 1,
 				     IIO_EV_TYPE_THRESH,
-				     (dir ? IIO_EV_DIR_RISING :
-					    IIO_EV_DIR_FALLING));
+				     (dir ? IIO_EV_DIR_FALLING :
+					    IIO_EV_DIR_RISING));
 	iio_push_event(indio_dev, event, data->timestamp);
 
 	/* Reset the interrupt flag */