Re: [PATCH 2/2] iio: magnetometer: Add Infineon TLV493D-A1B6

[Peter Meerwald-Stadler <pmeerw@pmeerw.net>]

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

comments below
 
> 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@infineon.com>
> Signed-off-by: Andreas Färber <afaerber@suse.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

link to datasheet would be nice

> + *
> + * 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)

please use TLV493D_ prefix; more descriptive naming or comments would be 
nice

> +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)

maybe move all these #defines on top of the file?

> +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;

why have this parameter if it is always 4?

> +	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);

use sizeof(buf) instead of 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];

maybe
u8 buf[4] = {0,};
> +
> +	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 = {					\

IIO buffer reads are not supported by the driver, so no need for 
.scan_type (here and for _TEMP)

> +			.sign = 's',				\
> +			.realbits = 12,				\
> +			.storagebits = 16,			\
> +			.endianness = IIO_CPU,			\
> +		},						\
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
> +			BIT(IIO_CHAN_INFO_PROCESSED),		\

either _RAW or _PROCESSED, not both

> +		.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:

this is ugly, why support _PROCESSED? 
just _RAW is fine

> +		do {
> +			ret = tlv493d_read_regs(s, buf, 7);
> +			if (ret)
> +				return ret;
> +		} while ((buf[3] & 0x3) || (buf[5] & BIT(4)));

maybe add a timeout or limit the number of retries

> +
> +		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;

no need to set val2 if returning VAL_INT

> +		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;

no need to set val2

> +			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;

what does this mean? some comment explaining the default mode?

> +	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");
> 

-- 

Peter Meerwald-Stadler
Mobile: +43 664 24 44 418