Date:   Sun, 10 Dec 2017 00:25:07 +0100
From:   Andreas Färber <afaerber@...e.de>
To:     linux-iio@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Andreas Färber <afaerber@...e.de>,
        Marius Tarcatu <marius.tarcatu@...ineon.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>
Subject: [PATCH 2/2] iio: magnetometer: Add Infineon TLV493D-A1B6

The Infineon TLV493D is a 3D magnetic sensor, A1B6 is I2C based.

It is found among others on the Infineon 3D Magnetic Sensor 2Go Kit,
which allows to detach the sensor as a breakout board.

Cc: Marius Tarcatu <marius.tarcatu@...ineon.com>
Signed-off-by: Andreas Färber <afaerber@...e.de>
---
 drivers/iio/magnetometer/Kconfig   |   9 +
 drivers/iio/magnetometer/Makefile  |   2 +
 drivers/iio/magnetometer/tlv493d.c | 328 +++++++++++++++++++++++++++++++++++++
 3 files changed, 339 insertions(+)
 create mode 100644 drivers/iio/magnetometer/tlv493d.c

diff --git a/drivers/iio/magnetometer/Kconfig b/drivers/iio/magnetometer/Kconfig
index ed9d776d01af..5945d88a1595 100644
--- a/drivers/iio/magnetometer/Kconfig
+++ b/drivers/iio/magnetometer/Kconfig
@@ -175,4 +175,13 @@ config SENSORS_HMC5843_SPI
 	  - hmc5843_core (core functions)
 	  - hmc5843_spi (support for HMC5983)
 
+config TLV493D
+	tristate "Infineon TLV493D 3D Magnetic Sensor"
+	depends on I2C
+	help
+	  Say Y here to build support for Infineon TLV493D-A1B6 I2C-based
+	  3-axis magnetometer.
+
+	  This driver can also be built as a module and will be called tlv493d.
+
 endmenu
diff --git a/drivers/iio/magnetometer/Makefile b/drivers/iio/magnetometer/Makefile
index 664b2f866472..df6ad23fee65 100644
--- a/drivers/iio/magnetometer/Makefile
+++ b/drivers/iio/magnetometer/Makefile
@@ -24,3 +24,5 @@ obj-$(CONFIG_IIO_ST_MAGN_SPI_3AXIS) += st_magn_spi.o
 obj-$(CONFIG_SENSORS_HMC5843)		+= hmc5843_core.o
 obj-$(CONFIG_SENSORS_HMC5843_I2C)	+= hmc5843_i2c.o
 obj-$(CONFIG_SENSORS_HMC5843_SPI)	+= hmc5843_spi.o
+
+obj-$(CONFIG_TLV493D) += tlv493d.o
diff --git a/drivers/iio/magnetometer/tlv493d.c b/drivers/iio/magnetometer/tlv493d.c
new file mode 100644
index 000000000000..d2fe296b2c80
--- /dev/null
+++ b/drivers/iio/magnetometer/tlv493d.c
@@ -0,0 +1,328 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Infineon TLV493D-A1B6 3D magnetic sensor
+ *
+ * Copyright (c) 2016-2017 Andreas Färber
+ */
+
+#include <linux/bitfield.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#define MOD1_LOW	BIT(0)
+#define MOD1_FAST	BIT(1)
+#define MOD1_INT	BIT(2)
+#define MOD1_P		BIT(7)
+
+#define MOD2_PT		BIT(5)
+
+struct tlv493d {
+	struct i2c_client *i2c;
+	struct iio_mount_matrix mount_matrix;
+	u8 factset1, factset2, factset3;
+};
+
+static int tlv493d_read_regs(struct tlv493d *s, u8 *buf, int len)
+{
+	int ret;
+
+	ret = i2c_master_recv(s->i2c, buf, len);
+	if (ret < len) {
+		dev_err(&s->i2c->dev, "failed to read registers (%d)", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static unsigned int tlv493d_parity(u32 v)
+{
+	v ^= v >> 16;
+	v ^= v >> 8;
+	v ^= v >> 4;
+	v &= 0xf;
+	return (0x6996 >> v) & 1;
+}
+
+#define MOD1_RES_MASK		(0x3 << 3)
+#define MOD1_IICADDR_MASK	(0x3 << 5)
+
+static int tlv493d_write_regs(struct tlv493d *s, const u8 *regs, int len)
+{
+	u8 buf[4];
+	int ret;
+
+	if (len != ARRAY_SIZE(buf))
+		return -EINVAL;
+
+	buf[0] = 0;
+	buf[1] = s->factset1 & (MOD1_IICADDR_MASK | MOD1_RES_MASK);
+	buf[1] |= regs[1] & ~(MOD1_P | MOD1_IICADDR_MASK | MOD1_RES_MASK);
+	buf[2] = s->factset2;
+	buf[3] = MOD2_PT | (s->factset3 & 0x1f);
+	buf[3] |= regs[3] & ~(MOD2_PT | 0x1f);
+
+	if ((buf[3] & MOD2_PT) &&
+	    !tlv493d_parity((buf[0] << 24) | (buf[1] << 16) | (buf[2] << 8) | buf[3]))
+		buf[1] |= MOD1_P;
+
+	ret = i2c_master_send(s->i2c, buf, 4);
+	if (ret < 4) {
+		dev_err(&s->i2c->dev, "failed to write registers (%d)", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int tlv493d_power_down(struct tlv493d *s)
+{
+	u8 buf[4];
+
+	buf[0] = 0;
+	buf[1] = 0;
+	buf[2] = 0;
+	buf[3] = 0;
+	return tlv493d_write_regs(s, buf, 4);
+}
+
+static const struct iio_mount_matrix *
+tlv493d_get_mount_matrix(const struct iio_dev *indio_dev,
+	const struct iio_chan_spec *chan)
+{
+	struct tlv493d *s = iio_priv(indio_dev);
+
+	return &s->mount_matrix;
+}
+
+static const struct iio_chan_spec_ext_info tlv493d_ext_info[] = {
+	IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, tlv493d_get_mount_matrix),
+	{}
+};
+
+#define TLV493D_AXIS_CHANNEL(axis, index)			\
+	{							\
+		.type = IIO_MAGN,				\
+		.channel2 = IIO_MOD_##axis,			\
+		.modified = 1,					\
+		.address = index,				\
+		.scan_index = index,				\
+		.scan_type = {					\
+			.sign = 's',				\
+			.realbits = 12,				\
+			.storagebits = 16,			\
+			.endianness = IIO_CPU,			\
+		},						\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
+			BIT(IIO_CHAN_INFO_PROCESSED),		\
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
+		.ext_info = tlv493d_ext_info,			\
+	}
+
+#define TLV493D_TEMP_CHANNEL(index)				\
+	{							\
+		.type = IIO_TEMP,				\
+		.channel2 = IIO_MOD_TEMP_OBJECT,		\
+		.modified = 1,					\
+		.address = index,				\
+		.scan_index = index,				\
+		.scan_type = {					\
+			.sign = 's',				\
+			.realbits = 12,				\
+			.storagebits = 16,			\
+			.endianness = IIO_CPU,			\
+		},						\
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
+			BIT(IIO_CHAN_INFO_OFFSET) |		\
+			BIT(IIO_CHAN_INFO_SCALE) |		\
+			BIT(IIO_CHAN_INFO_PROCESSED),		\
+	}
+
+static const struct iio_chan_spec tlv493d_channels[] = {
+	TLV493D_AXIS_CHANNEL(X, 0),
+	TLV493D_AXIS_CHANNEL(Y, 1),
+	TLV493D_AXIS_CHANNEL(Z, 2),
+	TLV493D_TEMP_CHANNEL(3),
+	IIO_CHAN_SOFT_TIMESTAMP(4),
+};
+
+static const unsigned long tlv493d_scan_masks[] = { 0xf, 0 };
+
+static int tlv493d_read_raw(struct iio_dev *indio_dev,
+	struct iio_chan_spec const *chan,
+	int *val, int *val2, long mask)
+{
+	struct tlv493d *s = iio_priv(indio_dev);
+	u8 buf[7];
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_PROCESSED:
+	case IIO_CHAN_INFO_RAW:
+		do {
+			ret = tlv493d_read_regs(s, buf, 7);
+			if (ret)
+				return ret;
+		} while ((buf[3] & 0x3) || (buf[5] & BIT(4)));
+
+		switch (chan->address) {
+		case 0:
+			*val = (((int)(s8)buf[0]) << 4) | (buf[4] >> 4);
+			break;
+		case 1:
+			*val = (((int)(s8)buf[1]) << 4) | (buf[4] & 0xf);
+			break;
+		case 2:
+			*val = (((int)(s8)buf[2]) << 4) | (buf[5] & 0xf);
+			break;
+		case 3:
+			*val = (((int)(s8)(buf[3] & 0xf0)) << 4) | buf[6];
+			if (mask != IIO_CHAN_INFO_RAW)
+				*val -= 340;
+			break;
+		default:
+			return -EINVAL;
+		}
+		*val2 = 0;
+		if (mask == IIO_CHAN_INFO_RAW)
+			return IIO_VAL_INT;
+
+		switch (chan->type) {
+		case IIO_MAGN:
+			*val2 = (*val * 1000000) * 98 / 1000;
+			*val = *val2 / 1000000;
+			*val2 %= 1000000;
+			break;
+		case IIO_TEMP:
+			*val2 = (*val * 1000000) * 11 / 10;
+			*val = *val2 / 1000000;
+			*val2 %= 1000000;
+			/* According to datasheet, LSB offset is for 25°C */
+			*val += 25;
+			break;
+		default:
+			return -EINVAL;
+		}
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_OFFSET:
+		switch (chan->type) {
+		case IIO_TEMP:
+			*val = -340;
+			*val2 = 0;
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_MAGN:
+			/* 0.098 mT/LSB */
+			*val = 0;
+			*val2 = 98000;
+			return IIO_VAL_INT_PLUS_MICRO;
+		case IIO_TEMP:
+			/* 1.1 °C/LSB */
+			*val = 1;
+			*val2 = 100000;
+			return IIO_VAL_INT_PLUS_MICRO;
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info tlv493d_iio_info = {
+	.read_raw = tlv493d_read_raw,
+};
+
+static int tlv493d_probe(struct i2c_client *i2c)
+{
+	struct iio_dev *indio_dev;
+	struct tlv493d *tlv493d;
+	u8 buf[10];
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&i2c->dev, sizeof(*tlv493d));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	tlv493d = iio_priv(indio_dev);
+	i2c_set_clientdata(i2c, indio_dev);
+	tlv493d->i2c = i2c;
+
+	ret = of_iio_read_mount_matrix(&i2c->dev, "mount-matrix",
+		&tlv493d->mount_matrix);
+	if (ret)
+		return ret;
+
+	indio_dev->dev.parent = &i2c->dev;
+	indio_dev->channels = tlv493d_channels;
+	indio_dev->num_channels = ARRAY_SIZE(tlv493d_channels);
+	indio_dev->info = &tlv493d_iio_info;
+	indio_dev->available_scan_masks = tlv493d_scan_masks;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->name = "tlv493d";
+
+	ret = tlv493d_read_regs(tlv493d, buf, 10);
+	if (ret)
+		return ret;
+
+	tlv493d->factset1 = buf[7];
+	tlv493d->factset2 = buf[8];
+	tlv493d->factset3 = buf[9];
+
+	buf[0] = 0;
+	buf[1] = MOD1_FAST | MOD1_LOW;
+	buf[2] = 0;
+	buf[3] = 0;
+	ret = tlv493d_write_regs(tlv493d, buf, 4);
+	if (ret)
+		return ret;
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&i2c->dev, "device registration failed");
+		tlv493d_power_down(tlv493d);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int tlv493d_remove(struct i2c_client *i2c)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(i2c);
+	struct tlv493d *tlv493d = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	tlv493d_power_down(tlv493d);
+
+	return 0;
+}
+
+static const struct of_device_id tlv493d_dt_ids[] = {
+	{ .compatible = "infineon,tlv493d-a1b6" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, tlv493d_dt_ids);
+
+static struct i2c_driver tlv493d_i2c_driver = {
+	.driver = {
+		.name = "tlv493d",
+		.of_match_table = tlv493d_dt_ids,
+	},
+	.probe_new = tlv493d_probe,
+	.remove = tlv493d_remove,
+};
+
+module_i2c_driver(tlv493d_i2c_driver);
+
+MODULE_DESCRIPTION("TLV493D I2C driver");
+MODULE_AUTHOR("Andreas Faerber");
+MODULE_LICENSE("GPL");
-- 
2.13.6

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