Date:   Wed, 15 Jul 2020 15:20:35 +0530
From:   Nishant Malpani <nish.malpani25@...il.com>
To:     jic23@...nel.org
Cc:     dragos.bogdan@...log.com, darius.berghe@...log.com,
        linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org
Subject: Re: [PATCH 1/2] iio: gyro: Add driver support for ADXRS290

Hello,

On 15/07/20 2:57 pm, Nishant Malpani wrote:
> ADXRS290 is a high performance MEMS pitch and roll (dual-axis in-plane)
> angular rate sensor (gyroscope) designed for use in stabilization
> applications. It also features an internal temperature sensor and
> programmable high-pass and low-pass filters.
> 
> Add support for ADXRS290 in direct-access mode for now.
> 
> Datasheet:
> Link: https://www.analog.com/media/en/technical-documentation/data-sheets/ADXRS290.pdf
> 
> Signed-off-by: Nishant Malpani <nish.malpani25@...il.com>
> ---
>   MAINTAINERS                 |   6 +
>   drivers/iio/gyro/Kconfig    |  10 +
>   drivers/iio/gyro/Makefile   |   1 +
>   drivers/iio/gyro/adxrs290.c | 490 ++++++++++++++++++++++++++++++++++++
>   4 files changed, 507 insertions(+)
>   create mode 100644 drivers/iio/gyro/adxrs290.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e016ee39c74a..dd02cfc410e8 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1098,6 +1098,12 @@ L:	linux-media@...r.kernel.org
>   S:	Maintained
>   F:	drivers/media/i2c/adv7842*
>   
> +ANALOG DEVICES INC ADXRS290 DRIVER
> +M:	Nishant Malpani <nish.malpani25@...il.com>
> +L:	linux-iio@...r.kernel.org
> +S:	Supported
> +F:	drivers/iio/gyro/adxrs290.c
> +
>   ANALOG DEVICES INC ASOC CODEC DRIVERS
>   M:	Lars-Peter Clausen <lars@...afoo.de>
>   M:	Nuno Sá <nuno.sa@...log.com>
> diff --git a/drivers/iio/gyro/Kconfig b/drivers/iio/gyro/Kconfig
> index 6daeddf37f60..024a34139875 100644
> --- a/drivers/iio/gyro/Kconfig
> +++ b/drivers/iio/gyro/Kconfig
> @@ -41,6 +41,16 @@ config ADIS16260
>   	  This driver can also be built as a module.  If so, the module
>   	  will be called adis16260.
>   
> +config ADXRS290
> +	tristate "Analog Devices ADXRS290 Dual-Axis MEMS Gyroscope SPI driver"
> +	depends on SPI
> +	help
> +	  Say yes here to build support for Analog Devices ADXRS290 programmable
> +	  digital output gyroscope.
> +
> +	  This driver can also be built as a module. If so, the module will be
> +	  called adxrs290.
> +
>   config ADXRS450
>   	tristate "Analog Devices ADXRS450/3 Digital Output Gyroscope SPI driver"
>   	depends on SPI
> diff --git a/drivers/iio/gyro/Makefile b/drivers/iio/gyro/Makefile
> index 45cbd5dc644e..0319b397dc3f 100644
> --- a/drivers/iio/gyro/Makefile
> +++ b/drivers/iio/gyro/Makefile
> @@ -8,6 +8,7 @@ obj-$(CONFIG_ADIS16080) += adis16080.o
>   obj-$(CONFIG_ADIS16130) += adis16130.o
>   obj-$(CONFIG_ADIS16136) += adis16136.o
>   obj-$(CONFIG_ADIS16260) += adis16260.o
> +obj-$(CONFIG_ADXRS290) += adxrs290.o
>   obj-$(CONFIG_ADXRS450) += adxrs450.o
>   obj-$(CONFIG_BMG160) += bmg160_core.o
>   obj-$(CONFIG_BMG160_I2C) += bmg160_i2c.o
> diff --git a/drivers/iio/gyro/adxrs290.c b/drivers/iio/gyro/adxrs290.c
> new file mode 100644
> index 000000000000..1139f79a3bd5
> --- /dev/null
> +++ b/drivers/iio/gyro/adxrs290.c
> @@ -0,0 +1,490 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * ADXRS290 SPI Gyroscope Driver
> + *
> + * Copyright (C) 2020 Analog Devices, Inc.
> + */
> +
> +#include <asm/unaligned.h>
> +#include <linux/bitfield.h>
> +#include <linux/device.h>
> +#include <linux/delay.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/spi/spi.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#define ADXRS290_ADI_ID		0xAD
> +#define ADXRS290_MEMS_ID	0x1D
> +#define ADXRS290_DEV_ID		0x92
> +
> +#define ADXRS290_REG_ADI_ID	0x00 /* Analog Devices Identifier Register */
> +#define ADXRS290_REG_MEMS_ID	0x01 /* MEMS Identifier Register */
> +#define ADXRS290_REG_DEV_ID	0x02 /* Device Identifier Register */
> +#define ADXRS290_REG_REV_ID	0x03 /* Silicon Revision Number Register */
> +#define ADXRS290_REG_SN0	0x04 /* Serial Number Registers, 4 bytes */
> +#define ADXRS290_REG_DATAX0	0x08 /* Roll Rate o/p Data Regs, 2 bytes */
> +#define ADXRS290_REG_DATAY0	0x0A /* Pitch Rate o/p Data Regs, 2 bytes */
> +#define ADXRS290_REG_TEMP0	0x0C /* Temperature Data Registers, 2 bytes */
> +#define ADXRS290_REG_POWER_CTL	0x10 /* Power Control Register */
> +#define ADXRS290_REG_FILTER	0x11 /* Band-pass Filter Register */
> +#define ADXRS290_REG_DATA_RDY	0x12 /* Data Ready Register */
> +
> +#define ADXRS290_READ		BIT(7)
> +#define ADXRS290_TSM		BIT(0)
> +#define ADXRS290_MEASUREMENT	BIT(1)
> +#define ADXRS290_SYNC		GENMASK(1, 0)
> +#define ADXRS290_LPF_MASK	GENMASK(2, 0)
> +#define ADXRS290_LPF(x)		FIELD_PREP(ADXRS290_LPF_MASK, x)
> +#define ADXRS290_HPF_MASK	GENMASK(7, 4)
> +#define ADXRS290_HPF(x)		FIELD_PREP(ADXRS290_HPF_MASK, x)
> +
> +#define ADXRS290_READ_REG(reg)	(ADXRS290_READ | (reg))
> +
> +#define ADXRS290_MAX_TRANSITION_TIME_MS 100
> +
> +enum adxrs290_mode {
> +	STANDBY,
> +	MEASUREMENT,
> +};
> +
> +struct adxrs290_state {
> +	struct spi_device	*spi;
> +	/* To atomize successive reads for single measurement */
> +	struct mutex		lock;
> +	enum adxrs290_mode	mode;
> +	unsigned int		lpf_3db_freq_idx;
> +	unsigned int		hpf_3db_freq_idx;
> +	union {
> +		u8 tx;
> +		u8 rx[2];
> +	}			data ____cacheline_aligned;
> +};
> +
> +/*
> + * Available cut-off frequencies of the low pass filter in Hz.
> + * The integer part and fractional part are represented separately.
> + */
> +static const unsigned int adxrs290_lpf_3db_freq_tbl[][2] = {
> +	[0] = {480, 0},
> +	[1] = {320, 0},
> +	[2] = {160, 0},
> +	[3] = {80, 0},
> +	[4] = {56, 600},
> +	[5] = {40, 0},
> +	[6] = {28, 300},
> +	[7] = {20, 0},
> +};
> +
> +/*
> + * Available cut-off frequencies of the high pass filter in Hz.
> + * The integer part and fractional part are represented separately.
> + */
> +static const unsigned int adxrs290_hpf_3db_freq_tbl[][2] = {
> +	[0] = {0, 0},
> +	[1] = {0, 11},
> +	[2] = {0, 22},
> +	[3] = {0, 44},
> +	[4] = {0, 87},
> +	[5] = {0, 175},
> +	[6] = {0, 350},
> +	[7] = {0, 700},
> +	[8] = {1, 400},
> +	[9] = {2, 800},
> +	[10] = {11, 300},
> +};
> +
> +static int adxrs290_spi_read16b(struct iio_dev *indio_dev, const u8 cmd,
> +				u16 *val)
> +{
> +	struct adxrs290_state *st = iio_priv(indio_dev);
> +	int ret = 0;
> +
> +	struct spi_transfer t[] = {
> +		{
> +			.tx_buf = &st->data.tx,
> +			.bits_per_word = 8,
> +			.len = sizeof(st->data.tx),
> +			.cs_change = 0,
> +		}, {
> +			.rx_buf = &st->data.rx,
> +			.bits_per_word = 8,
> +			.len = sizeof(st->data.rx),
> +		},
> +	};
> +
> +	mutex_lock(&st->lock);
> +
> +	st->data.tx = cmd;
> +	ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
> +
> +	if (ret < 0) {
> +		dev_err(&st->spi->dev, "error reading 16b from reg 0x%02x\n",
> +			cmd);
> +		goto err_unlock;
> +	}
> +
> +	*val = get_unaligned_le16(st->data.rx);
> +
> +err_unlock:
> +	mutex_unlock(&st->lock);
> +	return ret;
> +}
> +
> +static int adxrs290_get_rate_data(struct iio_dev *indio_dev, const u8 cmd,
> +				  unsigned int *val)
> +{
> +	int ret;
> +	u16 temp;
> +
> +	ret = adxrs290_spi_read16b(indio_dev, cmd, &temp);
> +	if (ret < 0)
> +		return ret;
> +
> +	*val = temp;
> +
> +	return 0;
> +}
> +
> +static int adxrs290_get_temp_data(struct iio_dev *indio_dev, unsigned int *val)
> +{
> +	const u8 cmd = ADXRS290_READ_REG(ADXRS290_REG_TEMP0);
> +	int ret;
> +	u16 temp;
> +
> +	ret = adxrs290_spi_read16b(indio_dev, cmd, &temp);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* extract lower 12 bits temperature reading */
> +	*val = temp & 0x0FFF;
> +
> +	return 0;
> +}
> +
> +static int adxrs290_get_3db_freq(struct iio_dev *indio_dev, u8 *val, u8 *val2)
> +{
> +	struct adxrs290_state *st = iio_priv(indio_dev);
> +	const u8 cmd = ADXRS290_READ_REG(ADXRS290_REG_FILTER);
> +	int temp;
> +
> +	temp = spi_w8r8(st->spi, cmd);
> +	if (temp < 0)
> +		return temp;
> +
> +	*val = FIELD_GET(ADXRS290_LPF_MASK, temp);
> +	*val2 = FIELD_GET(ADXRS290_HPF_MASK, temp);
> +
> +	return 0;
> +}
> +
> +static int adxrs290_spi_write_reg(struct spi_device *spi, const u8 reg,
> +				  const u8 val)
> +{
> +	u8 buf[2];
> +
> +	buf[0] = reg;
> +	buf[1] = val;
> +
> +	return spi_write(spi, buf, ARRAY_SIZE(buf));
> +}
> +
> +static unsigned int adxrs290_find_best_match(const unsigned int (*freq_tbl)[2],
> +					     unsigned int n, unsigned int freq)
> +{
> +	unsigned int i, best_freq_idx;
> +	unsigned int diff, best_diff;
> +
> +	best_freq_idx = 0;
> +	best_diff = UINT_MAX;
> +	for (i = 0; i < n; i++) {
> +		diff = abs(freq_tbl[i][0] - freq);

To find the "closest" 3db frequency from the acceptable ones, for now, I 
simply consider the integer part of the frequency (freq_tbl[i][0]). 
Taking into account the sensitivity of acceptable 3db frequencies for 
the high-pass filter [1], I'm guessing this isn't an acceptable 
solution. Should I progressively compare the fractional part after the 
integer part or perhaps directly exercise a FP arithmetic? Any other 
suggestions? Thanks in advance.

[1] Supported 3db frequencies of the high-pass filter:
0.000 0.011 0.022 0.044 0.087 0.175 0.350 0.700 1.400 2.800 11.300

With regards,
Nishant Malpani

> +		if (diff < best_diff) {
> +			best_diff = diff;
> +			best_freq_idx = i;
> +		}
> +	}
> +
> +	return best_freq_idx;
> +}
> +
> +static int adxrs290_set_filter_freq(struct iio_dev *indio_dev,
> +				    unsigned int lpf_idx, unsigned int hpf_idx)
> +{
> +	struct adxrs290_state *st = iio_priv(indio_dev);
> +	u8 val;
> +
> +	val = ADXRS290_HPF(hpf_idx) | ADXRS290_LPF(lpf_idx);
> +
> +	return adxrs290_spi_write_reg(st->spi, ADXRS290_REG_FILTER, val);
> +}
> +
> +static ssize_t adxrs290_show_avail(const unsigned int (*freq_tbl)[2], size_t n,
> +				   char *buf)
> +{
> +	ssize_t len = 0;
> +	int i;
> +
> +	for (i = 0; i < n; i++) {
> +		len += scnprintf(buf + len, PAGE_SIZE - len,
> +				 "%u.%03u ", freq_tbl[i][0], freq_tbl[i][1]);
> +	}
> +	buf[len - 1] = '\n';
> +
> +	return len;
> +}
> +
> +static ssize_t adxrs290_show_lpf_freq_avail(struct device *dev,
> +					    struct device_attribute *attr,
> +					    char *buf)
> +{
> +	return adxrs290_show_avail(adxrs290_lpf_3db_freq_tbl,
> +				   ARRAY_SIZE(adxrs290_lpf_3db_freq_tbl), buf);
> +}
> +
> +static ssize_t adxrs290_show_hpf_freq_avail(struct device *dev,
> +					    struct device_attribute *attr,
> +					    char *buf)
> +{
> +	return adxrs290_show_avail(adxrs290_hpf_3db_freq_tbl,
> +				   ARRAY_SIZE(adxrs290_hpf_3db_freq_tbl), buf);
> +}
> +
> +/* attribute to display available 3db frequencies for the low-pass filter */
> +static IIO_DEVICE_ATTR(in_anglvel_filter_low_pass_3db_frequency_available,
> +		       0444, adxrs290_show_lpf_freq_avail, NULL, 0);
> +
> +/* attribute to display available 3db frequencies for the high-pass filter */
> +static IIO_DEVICE_ATTR(in_anglvel_filter_high_pass_3db_frequency_available,
> +		       0444, adxrs290_show_hpf_freq_avail, NULL, 0);
> +
> +static struct attribute *adxrs290_attributes[] = {
> +	&iio_dev_attr_in_anglvel_filter_low_pass_3db_frequency_available.dev_attr.attr,
> +	&iio_dev_attr_in_anglvel_filter_high_pass_3db_frequency_available.dev_attr.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group adxrs290_attrs_group = {
> +	.attrs = adxrs290_attributes,
> +};
> +
> +static int adxrs290_initial_setup(struct iio_dev *indio_dev)
> +{
> +	struct adxrs290_state *st = iio_priv(indio_dev);
> +
> +	st->mode = MEASUREMENT;
> +
> +	return adxrs290_spi_write_reg(st->spi,
> +				      ADXRS290_REG_POWER_CTL,
> +				      ADXRS290_MEASUREMENT | ADXRS290_TSM);
> +}
> +
> +static int adxrs290_read_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int *val,
> +			     int *val2,
> +			     long mask)
> +{
> +	struct adxrs290_state *st = iio_priv(indio_dev);
> +	int ret;
> +	unsigned int t;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		switch (chan->type) {
> +		case IIO_ANGL_VEL:
> +			ret = adxrs290_get_rate_data(indio_dev,
> +						     ADXRS290_READ_REG(chan->address),
> +						     &t);
> +			if (ret < 0)
> +				return ret;
> +			*val = t;
> +			return IIO_VAL_INT;
> +		case IIO_TEMP:
> +			ret = adxrs290_get_temp_data(indio_dev, &t);
> +			if (ret < 0)
> +				return ret;
> +			*val = t;
> +			return IIO_VAL_INT;
> +		default:
> +			return -EINVAL;
> +		}
> +	case IIO_CHAN_INFO_SCALE:
> +		switch (chan->type) {
> +		case IIO_ANGL_VEL:
> +			*val = 0;
> +			*val2 = 87266;
> +			return IIO_VAL_INT_PLUS_NANO;
> +		case IIO_TEMP:
> +			*val = 100;
> +			return IIO_VAL_INT;
> +		default:
> +			return -EINVAL;
> +		}
> +	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
> +		switch (chan->type) {
> +		case IIO_ANGL_VEL:
> +			t = st->lpf_3db_freq_idx;
> +			*val = adxrs290_lpf_3db_freq_tbl[t][0];
> +			*val2 = adxrs290_lpf_3db_freq_tbl[t][1] * 1000;
> +			return IIO_VAL_INT_PLUS_MICRO;
> +		default:
> +			return -EINVAL;
> +		}
> +	case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
> +		switch (chan->type) {
> +		case IIO_ANGL_VEL:
> +			t = st->hpf_3db_freq_idx;
> +			*val = adxrs290_hpf_3db_freq_tbl[t][0];
> +			*val2 = adxrs290_hpf_3db_freq_tbl[t][1] * 1000;
> +			return IIO_VAL_INT_PLUS_MICRO;
> +		default:
> +			return -EINVAL;
> +		}
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int adxrs290_write_raw(struct iio_dev *indio_dev,
> +			      struct iio_chan_spec const *chan,
> +			      int val,
> +			      int val2,
> +			      long mask)
> +{
> +	struct adxrs290_state *st = iio_priv(indio_dev);
> +	unsigned int lpf_idx, hpf_idx;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
> +		lpf_idx = adxrs290_find_best_match(adxrs290_lpf_3db_freq_tbl,
> +						   ARRAY_SIZE(adxrs290_lpf_3db_freq_tbl),
> +						   val);
> +		/* caching the updated state of the low-pass filter */
> +		st->lpf_3db_freq_idx = lpf_idx;
> +		/* retrieving the current state of the high-pass filter */
> +		hpf_idx = st->hpf_3db_freq_idx;
> +		return adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> +	case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
> +		hpf_idx = adxrs290_find_best_match(adxrs290_hpf_3db_freq_tbl,
> +						   ARRAY_SIZE(adxrs290_hpf_3db_freq_tbl),
> +						   val);
> +		/* caching the updated state of the high-pass filter */
> +		st->hpf_3db_freq_idx = hpf_idx;
> +		/* retrieving the current state of the low-pass filter */
> +		lpf_idx = st->lpf_3db_freq_idx;
> +		return adxrs290_set_filter_freq(indio_dev, lpf_idx, hpf_idx);
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +#define ADXRS290_ANGL_VEL_CHANNEL(reg, axis) {				\
> +	.type = IIO_ANGL_VEL,						\
> +	.address = reg,							\
> +	.modified = 1,							\
> +	.channel2 = IIO_MOD_##axis,					\
> +	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),			\
> +	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |		\
> +	BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) |		\
> +	BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY),		\
> +}
> +
> +static const struct iio_chan_spec adxrs290_channels[] = {
> +	ADXRS290_ANGL_VEL_CHANNEL(ADXRS290_REG_DATAX0, X),
> +	ADXRS290_ANGL_VEL_CHANNEL(ADXRS290_REG_DATAY0, Y),
> +	{
> +		.type = IIO_TEMP,
> +		.address = ADXRS290_REG_TEMP0,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +		BIT(IIO_CHAN_INFO_SCALE),
> +	},
> +};
> +
> +static const struct iio_info adxrs290_info = {
> +	.attrs = &adxrs290_attrs_group,
> +	.read_raw = &adxrs290_read_raw,
> +	.write_raw = &adxrs290_write_raw,
> +};
> +
> +static int adxrs290_probe(struct spi_device *spi)
> +{
> +	struct iio_dev *indio_dev;
> +	struct adxrs290_state *st;
> +	int ret;
> +	u8 val, val2;
> +
> +	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	st = iio_priv(indio_dev);
> +	st->spi = spi;
> +	spi_set_drvdata(spi, indio_dev);
> +
> +	indio_dev->dev.parent = &spi->dev;
> +	indio_dev->name = "adxrs290";
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->channels = adxrs290_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(adxrs290_channels);
> +	indio_dev->info = &adxrs290_info;
> +
> +	val = spi_w8r8(spi, ADXRS290_READ_REG(ADXRS290_REG_ADI_ID));
> +	if (val != ADXRS290_ADI_ID) {
> +		dev_err(&spi->dev, "Wrong ADI ID 0x%02x\n", val);
> +		return -ENODEV;
> +	}
> +
> +	val = spi_w8r8(spi, ADXRS290_READ_REG(ADXRS290_REG_MEMS_ID));
> +	if (val != ADXRS290_MEMS_ID) {
> +		dev_err(&spi->dev, "Wrong MEMS ID 0x%02x\n", val);
> +		return -ENODEV;
> +	}
> +
> +	val = spi_w8r8(spi, ADXRS290_READ_REG(ADXRS290_REG_DEV_ID));
> +	if (val != ADXRS290_DEV_ID) {
> +		dev_err(&spi->dev, "Wrong DEV ID 0x%02x\n", val);
> +		return -ENODEV;
> +	}
> +
> +	/* default mode the gyroscope starts in */
> +	st->mode = STANDBY;
> +
> +	/* switch to measurement mode and switch on the temperature sensor */
> +	ret = adxrs290_initial_setup(indio_dev);
> +	if (ret < 0)
> +		return ret;
> +
> +	/* max transition time to measurement mode */
> +	msleep_interruptible(ADXRS290_MAX_TRANSITION_TIME_MS);
> +
> +	ret = adxrs290_get_3db_freq(indio_dev, &val, &val2);
> +	if (ret < 0)
> +		return ret;
> +
> +	st->lpf_3db_freq_idx = val;
> +	st->hpf_3db_freq_idx = val2;
> +
> +	return devm_iio_device_register(&spi->dev, indio_dev);
> +}
> +
> +static const struct of_device_id adxrs290_of_match[] = {
> +	{ .compatible = "adi,adxrs290" },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, adxrs290_of_match);
> +
> +static struct spi_driver adxrs290_driver = {
> +	.driver = {
> +		.name = "adxrs290",
> +		.of_match_table = adxrs290_of_match,
> +	},
> +	.probe = adxrs290_probe,
> +};
> +module_spi_driver(adxrs290_driver);
> +
> +MODULE_AUTHOR("Nishant Malpani <nish.malpani25@...il.com>");
> +MODULE_DESCRIPTION("Analog Devices ADXRS290 Gyroscope SPI driver");
> +MODULE_LICENSE("GPL");
> 

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