1 files changed, 157 insertions, 44 deletions

diff --git a/drivers/iio/magnetometer/ak8974.c b/drivers/iio/magnetometer/ak8974.c
index d32996702110..810fdfd37c88 100644
--- a/drivers/iio/magnetometer/ak8974.c
+++ b/drivers/iio/magnetometer/ak8974.c
@@ -49,6 +49,7 @@
 #define AK8974_WHOAMI_VALUE_AMI306 0x46
 #define AK8974_WHOAMI_VALUE_AMI305 0x47
 #define AK8974_WHOAMI_VALUE_AK8974 0x48
+#define AK8974_WHOAMI_VALUE_HSCDTD008A 0x49
 
 #define AK8974_DATA_X		0x10
 #define AK8974_DATA_Y		0x12
@@ -140,6 +141,12 @@
 #define AK8974_INT_CTRL_PULSE	BIT(1) /* 0 = latched; 1 = pulse (50 usec) */
 #define AK8974_INT_CTRL_RESDEF	(AK8974_INT_CTRL_XYZEN | AK8974_INT_CTRL_POL)
 
+/* HSCDTD008A-specific control register */
+#define HSCDTD008A_CTRL4	0x1E
+#define HSCDTD008A_CTRL4_MMD	BIT(7)	/* must be set to 1 */
+#define HSCDTD008A_CTRL4_RANGE	BIT(4)	/* 0 = 14-bit output; 1 = 15-bit output */
+#define HSCDTD008A_CTRL4_RESDEF	(HSCDTD008A_CTRL4_MMD | HSCDTD008A_CTRL4_RANGE)
+
 /* The AMI305 has elaborate FW version and serial number registers */
 #define AMI305_VER		0xE8
 #define AMI305_SN		0xEA
@@ -241,10 +248,17 @@ static int ak8974_reset(struct ak8974 *ak8974)
 	ret = regmap_write(ak8974->map, AK8974_CTRL3, AK8974_CTRL3_RESDEF);
 	if (ret)
 		return ret;
-	ret = regmap_write(ak8974->map, AK8974_INT_CTRL,
-			   AK8974_INT_CTRL_RESDEF);
-	if (ret)
-		return ret;
+	if (ak8974->variant != AK8974_WHOAMI_VALUE_HSCDTD008A) {
+		ret = regmap_write(ak8974->map, AK8974_INT_CTRL,
+				   AK8974_INT_CTRL_RESDEF);
+		if (ret)
+			return ret;
+	} else {
+		ret = regmap_write(ak8974->map, HSCDTD008A_CTRL4,
+				   HSCDTD008A_CTRL4_RESDEF);
+		if (ret)
+			return ret;
+	}
 
 	/* After reset, power off is default state */
 	return ak8974_set_power(ak8974, AK8974_PWR_OFF);
@@ -267,6 +281,8 @@ static int ak8974_configure(struct ak8974 *ak8974)
 		if (ret)
 			return ret;
 	}
+	if (ak8974->variant == AK8974_WHOAMI_VALUE_HSCDTD008A)
+		return 0;
 	ret = regmap_write(ak8974->map, AK8974_INT_CTRL, AK8974_INT_CTRL_POL);
 	if (ret)
 		return ret;
@@ -495,6 +511,10 @@ static int ak8974_detect(struct ak8974 *ak8974)
 		name = "ak8974";
 		dev_info(&ak8974->i2c->dev, "detected AK8974\n");
 		break;
+	case AK8974_WHOAMI_VALUE_HSCDTD008A:
+		name = "hscdtd008a";
+		dev_info(&ak8974->i2c->dev, "detected hscdtd008a\n");
+		break;
 	default:
 		dev_err(&ak8974->i2c->dev, "unsupported device (%02x) ",
 			whoami);
@@ -534,47 +554,103 @@ static int ak8974_detect(struct ak8974 *ak8974)
 	return 0;
 }
 
+static int ak8974_measure_channel(struct ak8974 *ak8974, unsigned long address,
+				  int *val)
+{
+	__le16 hw_values[3];
+	int ret;
+
+	pm_runtime_get_sync(&ak8974->i2c->dev);
+	mutex_lock(&ak8974->lock);
+
+	/*
+	 * We read all axes and discard all but one, for optimized
+	 * reading, use the triggered buffer.
+	 */
+	ret = ak8974_trigmeas(ak8974);
+	if (ret)
+		goto out_unlock;
+	ret = ak8974_getresult(ak8974, hw_values);
+	if (ret)
+		goto out_unlock;
+	/*
+	 * This explicit cast to (s16) is necessary as the measurement
+	 * is done in 2's complement with positive and negative values.
+	 * The follwing assignment to *val will then convert the signed
+	 * s16 value to a signed int value.
+	 */
+	*val = (s16)le16_to_cpu(hw_values[address]);
+out_unlock:
+	mutex_unlock(&ak8974->lock);
+	pm_runtime_mark_last_busy(&ak8974->i2c->dev);
+	pm_runtime_put_autosuspend(&ak8974->i2c->dev);
+
+	return ret;
+}
+
 static int ak8974_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan,
 			   int *val, int *val2,
 			   long mask)
 {
 	struct ak8974 *ak8974 = iio_priv(indio_dev);
-	__le16 hw_values[3];
-	int ret = -EINVAL;
-
-	pm_runtime_get_sync(&ak8974->i2c->dev);
-	mutex_lock(&ak8974->lock);
+	int ret;
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
 		if (chan->address > 2) {
 			dev_err(&ak8974->i2c->dev, "faulty channel address\n");
-			ret = -EIO;
-			goto out_unlock;
+			return -EIO;
 		}
-		ret = ak8974_trigmeas(ak8974);
-		if (ret)
-			goto out_unlock;
-		ret = ak8974_getresult(ak8974, hw_values);
+		ret = ak8974_measure_channel(ak8974, chan->address, val);
 		if (ret)
-			goto out_unlock;
-
-		/*
-		 * We read all axes and discard all but one, for optimized
-		 * reading, use the triggered buffer.
-		 */
-		*val = (s16)le16_to_cpu(hw_values[chan->address]);
-
-		ret = IIO_VAL_INT;
+			return ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		switch (ak8974->variant) {
+		case AK8974_WHOAMI_VALUE_AMI306:
+		case AK8974_WHOAMI_VALUE_AMI305:
+			/*
+			 * The datasheet for AMI305 and AMI306, page 6
+			 * specifies the range of the sensor to be
+			 * +/- 12 Gauss.
+			 */
+			*val = 12;
+			/*
+			 * 12 bits are used, +/- 2^11
+			 * [ -2048 .. 2047 ] (manual page 20)
+			 * [ 0xf800 .. 0x07ff ]
+			 */
+			*val2 = 11;
+			return IIO_VAL_FRACTIONAL_LOG2;
+		case AK8974_WHOAMI_VALUE_HSCDTD008A:
+			/*
+			 * The datasheet for HSCDTF008A, page 3 specifies the
+			 * range of the sensor as +/- 2.4 mT per axis, which
+			 * corresponds to +/- 2400 uT = +/- 24 Gauss.
+			 */
+			*val = 24;
+			/*
+			 * 15 bits are used (set up in CTRL4), +/- 2^14
+			 * [ -16384 .. 16383 ] (manual page 24)
+			 * [ 0xc000 .. 0x3fff ]
+			 */
+			*val2 = 14;
+			return IIO_VAL_FRACTIONAL_LOG2;
+		default:
+			/* GUESSING +/- 12 Gauss */
+			*val = 12;
+			/* GUESSING 12 bits ADC +/- 2^11 */
+			*val2 = 11;
+			return IIO_VAL_FRACTIONAL_LOG2;
+		}
+		break;
+	default:
+		/* Unknown request */
+		break;
 	}
 
- out_unlock:
-	mutex_unlock(&ak8974->lock);
-	pm_runtime_mark_last_busy(&ak8974->i2c->dev);
-	pm_runtime_put_autosuspend(&ak8974->i2c->dev);
-
-	return ret;
+	return -EINVAL;
 }
 
 static void ak8974_fill_buffer(struct iio_dev *indio_dev)
@@ -631,27 +707,44 @@ static const struct iio_chan_spec_ext_info ak8974_ext_info[] = {
 	{ },
 };
 
-#define AK8974_AXIS_CHANNEL(axis, index)				\
+#define AK8974_AXIS_CHANNEL(axis, index, bits)				\
 	{								\
 		.type = IIO_MAGN,					\
 		.modified = 1,						\
 		.channel2 = IIO_MOD_##axis,				\
-		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
+			BIT(IIO_CHAN_INFO_SCALE),			\
 		.ext_info = ak8974_ext_info,				\
 		.address = index,					\
 		.scan_index = index,					\
 		.scan_type = {						\
 			.sign = 's',					\
-			.realbits = 16,					\
+			.realbits = bits,				\
 			.storagebits = 16,				\
 			.endianness = IIO_LE				\
 		},							\
 	}
 
-static const struct iio_chan_spec ak8974_channels[] = {
-	AK8974_AXIS_CHANNEL(X, 0),
-	AK8974_AXIS_CHANNEL(Y, 1),
-	AK8974_AXIS_CHANNEL(Z, 2),
+/*
+ * We have no datasheet for the AK8974 but we guess that its
+ * ADC is 12 bits. The AMI305 and AMI306 certainly has 12bit
+ * ADC.
+ */
+static const struct iio_chan_spec ak8974_12_bits_channels[] = {
+	AK8974_AXIS_CHANNEL(X, 0, 12),
+	AK8974_AXIS_CHANNEL(Y, 1, 12),
+	AK8974_AXIS_CHANNEL(Z, 2, 12),
+	IIO_CHAN_SOFT_TIMESTAMP(3),
+};
+
+/*
+ * The HSCDTD008A has 15 bits resolution the way we set it up
+ * in CTRL4.
+ */
+static const struct iio_chan_spec ak8974_15_bits_channels[] = {
+	AK8974_AXIS_CHANNEL(X, 0, 15),
+	AK8974_AXIS_CHANNEL(Y, 1, 15),
+	AK8974_AXIS_CHANNEL(Z, 2, 15),
 	IIO_CHAN_SOFT_TIMESTAMP(3),
 };
 
@@ -674,18 +767,18 @@ static bool ak8974_writeable_reg(struct device *dev, unsigned int reg)
 	case AK8974_INT_CTRL:
 	case AK8974_INT_THRES:
 	case AK8974_INT_THRES + 1:
+		return true;
 	case AK8974_PRESET:
 	case AK8974_PRESET + 1:
-		return true;
+		return ak8974->variant != AK8974_WHOAMI_VALUE_HSCDTD008A;
 	case AK8974_OFFSET_X:
 	case AK8974_OFFSET_X + 1:
 	case AK8974_OFFSET_Y:
 	case AK8974_OFFSET_Y + 1:
 	case AK8974_OFFSET_Z:
 	case AK8974_OFFSET_Z + 1:
-		if (ak8974->variant == AK8974_WHOAMI_VALUE_AK8974)
-			return true;
-		return false;
+		return ak8974->variant == AK8974_WHOAMI_VALUE_AK8974 ||
+		       ak8974->variant == AK8974_WHOAMI_VALUE_HSCDTD008A;
 	case AMI305_OFFSET_X:
 	case AMI305_OFFSET_X + 1:
 	case AMI305_OFFSET_Y:
@@ -746,7 +839,12 @@ static int ak8974_probe(struct i2c_client *i2c,
 				      ARRAY_SIZE(ak8974->regs),
 				      ak8974->regs);
 	if (ret < 0) {
-		dev_err(&i2c->dev, "cannot get regulators\n");
+		if (ret != -EPROBE_DEFER)
+			dev_err(&i2c->dev, "cannot get regulators: %d\n", ret);
+		else
+			dev_dbg(&i2c->dev,
+				"regulators unavailable, deferring probe\n");
+
 		return ret;
 	}
 
@@ -795,8 +893,21 @@ static int ak8974_probe(struct i2c_client *i2c,
 	pm_runtime_put(&i2c->dev);
 
 	indio_dev->dev.parent = &i2c->dev;
-	indio_dev->channels = ak8974_channels;
-	indio_dev->num_channels = ARRAY_SIZE(ak8974_channels);
+	switch (ak8974->variant) {
+	case AK8974_WHOAMI_VALUE_AMI306:
+	case AK8974_WHOAMI_VALUE_AMI305:
+		indio_dev->channels = ak8974_12_bits_channels;
+		indio_dev->num_channels = ARRAY_SIZE(ak8974_12_bits_channels);
+		break;
+	case AK8974_WHOAMI_VALUE_HSCDTD008A:
+		indio_dev->channels = ak8974_15_bits_channels;
+		indio_dev->num_channels = ARRAY_SIZE(ak8974_15_bits_channels);
+		break;
+	default:
+		indio_dev->channels = ak8974_12_bits_channels;
+		indio_dev->num_channels = ARRAY_SIZE(ak8974_12_bits_channels);
+		break;
+	}
 	indio_dev->info = &ak8974_info;
 	indio_dev->available_scan_masks = ak8974_scan_masks;
 	indio_dev->modes = INDIO_DIRECT_MODE;
@@ -926,12 +1037,14 @@ static const struct i2c_device_id ak8974_id[] = {
 	{"ami305", 0 },
 	{"ami306", 0 },
 	{"ak8974", 0 },
+	{"hscdtd008a", 0 },
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, ak8974_id);
 
 static const struct of_device_id ak8974_of_match[] = {
 	{ .compatible = "asahi-kasei,ak8974", },
+	{ .compatible = "alps,hscdtd008a", },
 	{}
 };
 MODULE_DEVICE_TABLE(of, ak8974_of_match);