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Message-ID: <alpine.DEB.2.20.1712100953090.28826@vps.pmeerw.net>
Date: Sun, 10 Dec 2017 10:08:04 +0100 (CET)
From: Peter Meerwald-Stadler <pmeerw@...erw.net>
To: Andreas Färber <afaerber@...e.de>
cc: linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
Marius Tarcatu <marius.tarcatu@...ineon.com>,
Jonathan Cameron <jic23@...nel.org>,
Hartmut Knaack <knaack.h@....de>,
Lars-Peter Clausen <lars@...afoo.de>
Subject: Re: [PATCH 2/2] iio: magnetometer: Add Infineon TLV493D-A1B6
> 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@...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
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
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