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Date:   Thu, 2 Aug 2018 14:58:06 +0100
From:   Jonathan Cameron <jonathan.cameron@huawei.com>
To:     "Popa, Stefan Serban" <StefanSerban.Popa@analog.com>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "lars@metafoo.de" <lars@metafoo.de>,
        "knaack.h@gmx.de" <knaack.h@gmx.de>,
        "jic23@kernel.org" <jic23@kernel.org>,
        "Hennerich, Michael" <Michael.Hennerich@analog.com>,
        "linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>,
        "pmeerw@pmeerw.net" <pmeerw@pmeerw.net>,
        "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v2 1/6] iio: adxl372: New driver for Analog Devices
 ADXL372 Accelerometer
Message-ID: <20180802145806.00000348@huawei.com>
In-Reply-To: <1533217970.18921.4.camel@analog.com>
References: <1533136389-31600-1-git-send-email-stefan.popa@analog.com>
        <20180802140546.00001074@huawei.com>
        <1533217970.18921.4.camel@analog.com>
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On Thu, 2 Aug 2018 13:52:54 +0000
"Popa, Stefan Serban" <StefanSerban.Popa@analog.com> wrote:

> On Jo, 2018-08-02 at 14:05 +0100, Jonathan Cameron wrote:
> > On Wed, 1 Aug 2018 18:13:09 +0300
> > Stefan Popa <stefan.popa@analog.com> wrote:
> >   
> > > 
> > > This patch adds basic support for Analog Devices ADXL372 SPI-Bus
> > > Three-Axis Digital Accelerometer.
> > > 
> > > The device is probed and configured the with some initial default
> > > values. With this basic driver, it is possible to read raw acceleration
> > > data.
> > > 
> > > Datasheet:
> > > http://www.analog.com/media/en/technical-documentation/data-sheets/ADXL
> > > 372.pdf
> > > 
> > > Signed-off-by: Stefan Popa <stefan.popa@analog.com>  
> > Hi Stefan,
> > 
> > I would have preferred a cover letter (if nothing else it keeps them
> > together in
> > a thread in people's email clients)
> > 
> > I've just reviewed all of these and I think the only real outstanding
> > issue
> > is Mark's requests for small changes in the regmap stuff.
> > 
> > The open question on what to do long term about 'peak' and similar
> > derived
> > channels can probably wait for another day.
> > 
> > Thanks,
> >   
> Hi Jonathan,?
> 
> Thank you very much for your review!?
> 
> If you agree, let's leave the 'peak' mode out of this first version of the
> driver.
> 
That makes life easier, so let's go that way.

This has missed the coming merge window, so we might even get that sorted before
the following window anyway!

Jonathan

> -Stefan
> 
> >   
> > > 
> > > ---
> > > Changes in v2:
> > > 	- removed ADXL372_RD_FLAG_MSK and ADXL372_WR_FLAG_MSK macros.
> > > 	- handled regmap read/write by setting reg_bits and pad_bits
> > > 	??fields in regmap_config struct.
> > > 	- removed the buffer specifications when defining the channels.
> > > 	- changed the activity and inactivity thresholds.
> > > 	- added two new functions for setting the activity and inactivity
> > > 	??timers: adxl372_set_inactivity_time_ms() and
> > > 	??adxl372_set_activity_time_ms().
> > > 
> > > ?MAINTAINERS?????????????????|???6 +
> > > ?drivers/iio/accel/Kconfig???|??11 +
> > > ?drivers/iio/accel/Makefile??|???1 +
> > > ?drivers/iio/accel/adxl372.c | 530
> > > ++++++++++++++++++++++++++++++++++++++++++++
> > > ?4 files changed, 548 insertions(+)
> > > ?create mode 100644 drivers/iio/accel/adxl372.c
> > > 
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index 60b1028..2ba47bb 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -543,6 +543,12 @@ W:	http://ez.analog.com/community/linux-dev
> > > ice-drivers
> > > ?S:	Supported
> > > ?F:	drivers/input/misc/adxl34x.c
> > > ?
> > > +ADXL372 THREE-AXIS DIGITAL ACCELEROMETER DRIVER
> > > +M:	Stefan Popa <stefan.popa@analog.com>
> > > +W:	http://ez.analog.com/community/linux-device-drivers
> > > +S:	Supported
> > > +F:	drivers/iio/accel/adxl372.c
> > > +
> > > ?AF9013 MEDIA DRIVER
> > > ?M:	Antti Palosaari <crope@iki.fi>
> > > ?L:	linux-media@vger.kernel.org
> > > diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
> > > index 62ae7e5..1b496ef 100644
> > > --- a/drivers/iio/accel/Kconfig
> > > +++ b/drivers/iio/accel/Kconfig
> > > @@ -60,6 +60,17 @@ config ADXL345_SPI
> > > ?	??will be called adxl345_spi and you will also get
> > > adxl345_core
> > > ?	??for the core module.
> > > ?
> > > +config ADXL372
> > > +	tristate "Analog Devices ADXL372 3-Axis Accelerometer Driver"
> > > +	depends on SPI
> > > +	select IIO_BUFFER
> > > +	select IIO_TRIGGERED_BUFFER
> > > +	help
> > > +	??Say yes here to add support for the Analog Devices ADXL372
> > > triaxial
> > > +	??acceleration sensor.
> > > +	??To compile this driver as a module, choose M here: the
> > > +	??module will be called adxl372.
> > > +
> > > ?config BMA180
> > > ?	tristate "Bosch BMA180/BMA250 3-Axis Accelerometer Driver"
> > > ?	depends on I2C
> > > diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
> > > index 636d4d1..5758ffc 100644
> > > --- a/drivers/iio/accel/Makefile
> > > +++ b/drivers/iio/accel/Makefile
> > > @@ -9,6 +9,7 @@ obj-$(CONFIG_ADIS16209) += adis16209.o
> > > ?obj-$(CONFIG_ADXL345) += adxl345_core.o
> > > ?obj-$(CONFIG_ADXL345_I2C) += adxl345_i2c.o
> > > ?obj-$(CONFIG_ADXL345_SPI) += adxl345_spi.o
> > > +obj-$(CONFIG_ADXL372) += adxl372.o
> > > ?obj-$(CONFIG_BMA180) += bma180.o
> > > ?obj-$(CONFIG_BMA220) += bma220_spi.o
> > > ?obj-$(CONFIG_BMC150_ACCEL) += bmc150-accel-core.o
> > > diff --git a/drivers/iio/accel/adxl372.c b/drivers/iio/accel/adxl372.c
> > > new file mode 100644
> > > index 0000000..7d5092d
> > > --- /dev/null
> > > +++ b/drivers/iio/accel/adxl372.c
> > > @@ -0,0 +1,530 @@
> > > +// SPDX-License-Identifier: GPL-2.0+
> > > +/*
> > > + * ADXL372 3-Axis Digital Accelerometer SPI driver
> > > + *
> > > + * Copyright 2018 Analog Devices Inc.
> > > + */
> > > +
> > > +#include <linux/bitops.h>
> > > +#include <linux/module.h>
> > > +#include <linux/regmap.h>
> > > +#include <linux/spi/spi.h>
> > > +
> > > +#include <linux/iio/iio.h>
> > > +#include <linux/iio/sysfs.h>
> > > +
> > > +/* ADXL372 registers definition */
> > > +#define ADXL372_DEVID			0x00
> > > +#define ADXL372_DEVID_MST		0x01
> > > +#define ADXL372_PARTID			0x02
> > > +#define ADXL372_REVID			0x03
> > > +#define ADXL372_STATUS_1		0x04
> > > +#define ADXL372_STATUS_2		0x05
> > > +#define ADXL372_FIFO_ENTRIES_2		0x06
> > > +#define ADXL372_FIFO_ENTRIES_1		0x07
> > > +#define ADXL372_X_DATA_H		0x08
> > > +#define ADXL372_X_DATA_L		0x09
> > > +#define ADXL372_Y_DATA_H		0x0A
> > > +#define ADXL372_Y_DATA_L		0x0B
> > > +#define ADXL372_Z_DATA_H		0x0C
> > > +#define ADXL372_Z_DATA_L		0x0D
> > > +#define ADXL372_X_MAXPEAK_H		0x15
> > > +#define ADXL372_X_MAXPEAK_L		0x16
> > > +#define ADXL372_Y_MAXPEAK_H		0x17
> > > +#define ADXL372_Y_MAXPEAK_L		0x18
> > > +#define ADXL372_Z_MAXPEAK_H		0x19
> > > +#define ADXL372_Z_MAXPEAK_L		0x1A
> > > +#define ADXL372_OFFSET_X		0x20
> > > +#define ADXL372_OFFSET_Y		0x21
> > > +#define ADXL372_OFFSET_Z		0x22
> > > +#define ADXL372_X_THRESH_ACT_H		0x23
> > > +#define ADXL372_X_THRESH_ACT_L		0x24
> > > +#define ADXL372_Y_THRESH_ACT_H		0x25
> > > +#define ADXL372_Y_THRESH_ACT_L		0x26
> > > +#define ADXL372_Z_THRESH_ACT_H		0x27
> > > +#define ADXL372_Z_THRESH_ACT_L		0x28
> > > +#define ADXL372_TIME_ACT		0x29
> > > +#define ADXL372_X_THRESH_INACT_H	0x2A
> > > +#define ADXL372_X_THRESH_INACT_L	0x2B
> > > +#define ADXL372_Y_THRESH_INACT_H	0x2C
> > > +#define ADXL372_Y_THRESH_INACT_L	0x2D
> > > +#define ADXL372_Z_THRESH_INACT_H	0x2E
> > > +#define ADXL372_Z_THRESH_INACT_L	0x2F
> > > +#define ADXL372_TIME_INACT_H		0x30
> > > +#define ADXL372_TIME_INACT_L		0x31
> > > +#define ADXL372_X_THRESH_ACT2_H		0x32
> > > +#define ADXL372_X_THRESH_ACT2_L		0x33
> > > +#define ADXL372_Y_THRESH_ACT2_H		0x34
> > > +#define ADXL372_Y_THRESH_ACT2_L		0x35
> > > +#define ADXL372_Z_THRESH_ACT2_H		0x36
> > > +#define ADXL372_Z_THRESH_ACT2_L		0x37
> > > +#define ADXL372_HPF			0x38
> > > +#define ADXL372_FIFO_SAMPLES		0x39
> > > +#define ADXL372_FIFO_CTL		0x3A
> > > +#define ADXL372_INT1_MAP		0x3B
> > > +#define ADXL372_INT2_MAP		0x3C
> > > +#define ADXL372_TIMING			0x3D
> > > +#define ADXL372_MEASURE			0x3E
> > > +#define ADXL372_POWER_CTL		0x3F
> > > +#define ADXL372_SELF_TEST		0x40
> > > +#define ADXL372_RESET			0x41
> > > +#define ADXL372_FIFO_DATA		0x42
> > > +
> > > +#define ADXL372_DEVID_VAL		0xAD
> > > +#define ADXL372_PARTID_VAL		0xFA
> > > +#define ADXL372_RESET_CODE		0x52
> > > +
> > > +/* ADXL372_POWER_CTL */
> > > +#define ADXL372_POWER_CTL_MODE_MSK		GENMASK_ULL(1, 0)
> > > +#define ADXL372_POWER_CTL_MODE(x)		(((x) & 0x3) << 0)
> > > +
> > > +/* ADXL372_MEASURE */
> > > +#define ADXL372_MEASURE_LINKLOOP_MSK		GENMASK_ULL(5, 4)
> > > +#define ADXL372_MEASURE_LINKLOOP_MODE(x)	(((x) & 0x3) << 4)
> > > +#define ADXL372_MEASURE_BANDWIDTH_MSK		GENMASK_ULL(2, 0)
> > > +#define ADXL372_MEASURE_BANDWIDTH_MODE(x)	(((x) & 0x7) << 0)
> > > +
> > > +/* ADXL372_TIMING */
> > > +#define ADXL372_TIMING_ODR_MSK			GENMASK_ULL(7,
> > > 5)
> > > +#define ADXL372_TIMING_ODR_MODE(x)		(((x) & 0x7) << 5)
> > > +
> > > +/* ADXL372_FIFO_CTL */
> > > +#define ADXL372_FIFO_CTL_FORMAT_MSK		GENMASK(5, 3)
> > > +#define ADXL372_FIFO_CTL_FORMAT_MODE(x)		(((x) & 0x7) <<
> > > 3)
> > > +#define ADXL372_FIFO_CTL_MODE_MSK		GENMASK(2, 1)
> > > +#define ADXL372_FIFO_CTL_MODE_MODE(x)		(((x) & 0x3) <<
> > > 1)
> > > +#define ADXL372_FIFO_CTL_SAMPLES_MSK		BIT(1)
> > > +#define ADXL372_FIFO_CTL_SAMPLES_MODE(x)	(((x) > 0xFF) ? 1 : 0)
> > > +
> > > +/* ADXL372_STATUS_1 */
> > > +#define ADXL372_STATUS_1_DATA_RDY(x)		(((x) >> 0) & 0x1)
> > > +#define ADXL372_STATUS_1_FIFO_RDY(x)		(((x) >> 1) & 0x1)
> > > +#define ADXL372_STATUS_1_FIFO_FULL(x)		(((x) >> 2) &
> > > 0x1)
> > > +#define ADXL372_STATUS_1_FIFO_OVR(x)		(((x) >> 3) & 0x1)
> > > +#define ADXL372_STATUS_1_USR_NVM_BUSY(x)	(((x) >> 5) & 0x1)
> > > +#define ADXL372_STATUS_1_AWAKE(x)		(((x) >> 6) & 0x1)
> > > +#define ADXL372_STATUS_1_ERR_USR_REGS(x)	(((x) >> 7) & 0x1)
> > > +
> > > +/* ADXL372_INT1_MAP */
> > > +#define ADXL372_INT1_MAP_DATA_RDY_MSK		BIT(0)
> > > +#define ADXL372_INT1_MAP_DATA_RDY_MODE(x)	(((x) & 0x1) << 0)
> > > +#define ADXL372_INT1_MAP_FIFO_RDY_MSK		BIT(1)
> > > +#define ADXL372_INT1_MAP_FIFO_RDY_MODE(x)	(((x) & 0x1) << 1)
> > > +#define ADXL372_INT1_MAP_FIFO_FULL_MSK		BIT(2)
> > > +#define ADXL372_INT1_MAP_FIFO_FULL_MODE(x)	(((x) & 0x1) << 2)
> > > +#define ADXL372_INT1_MAP_FIFO_OVR_MSK		BIT(3)
> > > +#define ADXL372_INT1_MAP_FIFO_OVR_MODE(x)	(((x) & 0x1) << 3)
> > > +#define ADXL372_INT1_MAP_INACT_MSK		BIT(4)
> > > +#define ADXL372_INT1_MAP_INACT_MODE(x)		(((x) & 0x1) <<
> > > 4)
> > > +#define ADXL372_INT1_MAP_ACT_MSK		BIT(5)
> > > +#define ADXL372_INT1_MAP_ACT_MODE(x)		(((x) & 0x1) << 5)
> > > +#define ADXL372_INT1_MAP_AWAKE_MSK		BIT(6)
> > > +#define ADXL372_INT1_MAP_AWAKE_MODE(x)		(((x) & 0x1) <<
> > > 6)
> > > +#define ADXL372_INT1_MAP_LOW_MSK		BIT(7)
> > > +#define ADXL372_INT1_MAP_LOW_MODE(x)		(((x) & 0x1) << 7)
> > > +
> > > +/*
> > > + * At +/- 200g with 12-bit resolution, scale is computed as:
> > > + * (200 + 200) * 9.81 / (2^12 - 1) = 0.958241
> > > + */
> > > +#define ADXL372_USCALE	958241
> > > +
> > > +enum adxl372_op_mode {
> > > +	ADXL372_STANDBY,
> > > +	ADXL372_WAKE_UP,
> > > +	ADXL372_INSTANT_ON,
> > > +	ADXL372_FULL_BW_MEASUREMENT,
> > > +};
> > > +
> > > +enum adxl372_act_proc_mode {
> > > +	ADXL372_DEFAULT,
> > > +	ADXL372_LINKED,
> > > +	ADXL372_LOOPED,
> > > +};
> > > +
> > > +enum adxl372_th_activity {
> > > +	ADXL372_ACTIVITY,
> > > +	ADXL372_ACTIVITY2,
> > > +	ADXL372_INACTIVITY,
> > > +};
> > > +
> > > +enum adxl372_odr {
> > > +	ADXL372_ODR_400HZ,
> > > +	ADXL372_ODR_800HZ,
> > > +	ADXL372_ODR_1600HZ,
> > > +	ADXL372_ODR_3200HZ,
> > > +	ADXL372_ODR_6400HZ,
> > > +};
> > > +
> > > +enum adxl372_bandwidth {
> > > +	ADXL372_BW_200HZ,
> > > +	ADXL372_BW_400HZ,
> > > +	ADXL372_BW_800HZ,
> > > +	ADXL372_BW_1600HZ,
> > > +	ADXL372_BW_3200HZ,
> > > +};
> > > +
> > > +#define ADXL372_ACCEL_CHANNEL(index, reg, axis) {			
> > > \
> > > +	.type = IIO_ACCEL,						
> > > \
> > > +	.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),		
> > > \
> > > +}
> > > +
> > > +static const struct iio_chan_spec adxl372_channels[] = {
> > > +	ADXL372_ACCEL_CHANNEL(0, ADXL372_X_DATA_H, X),
> > > +	ADXL372_ACCEL_CHANNEL(1, ADXL372_Y_DATA_H, Y),
> > > +	ADXL372_ACCEL_CHANNEL(2, ADXL372_Z_DATA_H, Z),
> > > +};
> > > +
> > > +struct adxl372_state {
> > > +	struct spi_device		*spi;
> > > +	struct regmap			*regmap;
> > > +	enum adxl372_op_mode		op_mode;
> > > +	enum adxl372_act_proc_mode	act_proc_mode;
> > > +	enum adxl372_odr		odr;
> > > +	enum adxl372_bandwidth		bw;
> > > +	u32				act_time_ms;
> > > +	u32				inact_time_ms;
> > > +};
> > > +
> > > +static int adxl372_read_axis(struct adxl372_state *st, u8 addr)
> > > +{
> > > +	__be16 regval;
> > > +	int ret;
> > > +
> > > +	ret = regmap_bulk_read(st->regmap, addr, &regval,
> > > sizeof(regval));
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	return be16_to_cpu(regval);
> > > +}
> > > +
> > > +static int adxl372_set_op_mode(struct adxl372_state *st,
> > > +			???????enum adxl372_op_mode op_mode)
> > > +{
> > > +	int ret;
> > > +
> > > +	ret = regmap_update_bits(st->regmap, ADXL372_POWER_CTL,
> > > +				?ADXL372_POWER_CTL_MODE_MSK,
> > > +				?ADXL372_POWER_CTL_MODE(op_mode));
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	st->op_mode = op_mode;
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static int adxl372_set_odr(struct adxl372_state *st,
> > > +			???enum adxl372_odr odr)
> > > +{
> > > +	int ret;
> > > +
> > > +	ret = regmap_update_bits(st->regmap, ADXL372_TIMING,
> > > +				?ADXL372_TIMING_ODR_MSK,
> > > +				?ADXL372_TIMING_ODR_MODE(odr));
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	st->odr = odr;
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static int adxl372_set_bandwidth(struct adxl372_state *st,
> > > +				?enum adxl372_bandwidth bw)
> > > +{
> > > +	int ret;
> > > +
> > > +	ret = regmap_update_bits(st->regmap, ADXL372_MEASURE,
> > > +				?ADXL372_MEASURE_BANDWIDTH_MSK,
> > > +				?ADXL372_MEASURE_BANDWIDTH_MODE(bw));
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	st->bw = bw;
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static int adxl372_set_act_proc_mode(struct adxl372_state *st,
> > > +				?????enum adxl372_act_proc_mode mode)
> > > +{
> > > +	int ret;
> > > +
> > > +	ret = regmap_update_bits(st->regmap,
> > > +				?ADXL372_MEASURE,
> > > +				?ADXL372_MEASURE_LINKLOOP_MSK,
> > > +				?ADXL372_MEASURE_LINKLOOP_MODE(mode));
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	st->act_proc_mode = mode;
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static int adxl372_set_activity_threshold(struct adxl372_state *st,
> > > +					??enum adxl372_th_activity
> > > act,
> > > +					??bool ref_en, bool enable,
> > > +					??unsigned int threshold)
> > > +{
> > > +	unsigned char buf[6];
> > > +	unsigned char th_reg_high_val, th_reg_low_val,
> > > th_reg_high_addr;
> > > +
> > > +	/* scale factor is 100 mg/code */
> > > +	th_reg_high_val = (threshold / 100) >> 3;
> > > +	th_reg_low_val = ((threshold / 100) << 5) | (ref_en << 1) |
> > > enable;
> > > +
> > > +	switch (act) {
> > > +	case ADXL372_ACTIVITY:
> > > +		th_reg_high_addr = ADXL372_X_THRESH_ACT_H;
> > > +		break;
> > > +	case ADXL372_ACTIVITY2:
> > > +		th_reg_high_addr = ADXL372_X_THRESH_ACT2_H;
> > > +		break;
> > > +	case ADXL372_INACTIVITY:
> > > +		th_reg_high_addr = ADXL372_X_THRESH_INACT_H;
> > > +		break;
> > > +	}
> > > +
> > > +	buf[0] = th_reg_high_val;
> > > +	buf[1] = th_reg_low_val;
> > > +	buf[2] = th_reg_high_val;
> > > +	buf[3] = th_reg_low_val;
> > > +	buf[4] = th_reg_high_val;
> > > +	buf[5] = th_reg_low_val;
> > > +
> > > +	return regmap_bulk_write(st->regmap, th_reg_high_addr,
> > > +				?buf, ARRAY_SIZE(buf));
> > > +}
> > > +
> > > +static int adxl372_set_activity_time_ms(struct adxl372_state *st,
> > > +					unsigned int act_time_ms)
> > > +{
> > > +	unsigned int reg_val, scale_factor;
> > > +	int ret;
> > > +
> > > +	/*
> > > +	?* 3.3 ms per code is the scale factor of the TIME_ACT
> > > register for
> > > +	?* ODR = 6400 Hz. It is 6.6 ms per code for ODR = 3200 Hz and
> > > below.
> > > +	?*/
> > > +	if (st->odr == ADXL372_ODR_6400HZ)
> > > +		scale_factor = 3300;
> > > +	else
> > > +		scale_factor = 6600;
> > > +
> > > +	reg_val = DIV_ROUND_CLOSEST(act_time_ms * 1000, scale_factor);
> > > +
> > > +	/* TIME_ACT register is 8 bits wide */
> > > +	if (reg_val > 0xFF)
> > > +		reg_val = 0xFF;
> > > +
> > > +	ret = regmap_write(st->regmap, ADXL372_TIME_ACT, reg_val);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	st->act_time_ms = act_time_ms;
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static int adxl372_set_inactivity_time_ms(struct adxl372_state *st,
> > > +					??unsigned int inact_time_ms)
> > > +{
> > > +	unsigned int reg_val_h, reg_val_l, res, scale_factor;
> > > +	int ret;
> > > +
> > > +	/*
> > > +	?* 13 ms per code is the scale factor of the TIME_INACT
> > > register for
> > > +	?* ODR = 6400 Hz. It is 26 ms per code for ODR = 3200 Hz and
> > > below.
> > > +	?*/
> > > +	if (st->odr == ADXL372_ODR_6400HZ)
> > > +		scale_factor = 13;
> > > +	else
> > > +		scale_factor = 26;
> > > +
> > > +	res = DIV_ROUND_CLOSEST(inact_time_ms, scale_factor);
> > > +	reg_val_h = (res >> 8) & 0xFF;
> > > +	reg_val_l = res & 0xFF;
> > > +
> > > +	ret = regmap_write(st->regmap, ADXL372_TIME_INACT_H,
> > > reg_val_h);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	ret = regmap_write(st->regmap, ADXL372_TIME_INACT_L,
> > > reg_val_l);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	st->inact_time_ms = inact_time_ms;
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static int adxl372_setup(struct adxl372_state *st)
> > > +{
> > > +	unsigned int regval;
> > > +	int ret;
> > > +
> > > +	ret = regmap_read(st->regmap, ADXL372_DEVID, &regval);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	if (regval != ADXL372_DEVID_VAL) {
> > > +		dev_err(&st->spi->dev, "Invalid chip id %x\n",
> > > regval);
> > > +		return -ENODEV;
> > > +	}
> > > +
> > > +	ret = adxl372_set_op_mode(st, ADXL372_STANDBY);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	/* Set threshold for activity detection to 1g */
> > > +	ret = adxl372_set_activity_threshold(st, ADXL372_ACTIVITY,
> > > +					?????true, true, 1000);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	/* Set threshold for inactivity detection to 100mg */
> > > +	ret = adxl372_set_activity_threshold(st, ADXL372_INACTIVITY,
> > > +					?????true, true, 100);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	/* Set activity processing in Looped mode */
> > > +	ret = adxl372_set_act_proc_mode(st, ADXL372_LOOPED);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	ret = adxl372_set_odr(st, ADXL372_ODR_6400HZ);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	ret = adxl372_set_bandwidth(st, ADXL372_BW_3200HZ);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	/* Set activity timer to 1ms */
> > > +	ret = adxl372_set_activity_time_ms(st, 1);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	/* Set inactivity timer to 10s */
> > > +	ret = adxl372_set_inactivity_time_ms(st, 10000);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	/* Set the mode of operation to full bandwidth measurement
> > > mode */
> > > +	return adxl372_set_op_mode(st, ADXL372_FULL_BW_MEASUREMENT);
> > > +}
> > > +
> > > +static int adxl372_reg_access(struct iio_dev *indio_dev,
> > > +			??????unsigned int reg,
> > > +			??????unsigned int writeval,
> > > +			??????unsigned int *readval)
> > > +{
> > > +	struct adxl372_state *st = iio_priv(indio_dev);
> > > +
> > > +	if (readval)
> > > +		return regmap_read(st->regmap, reg, readval);
> > > +	else
> > > +		return regmap_write(st->regmap, reg, writeval);
> > > +}
> > > +
> > > +static int adxl372_read_raw(struct iio_dev *indio_dev,
> > > +			????struct iio_chan_spec const *chan,
> > > +			????int *val, int *val2, long info)
> > > +{
> > > +	struct adxl372_state *st = iio_priv(indio_dev);
> > > +	int ret;
> > > +
> > > +	switch (info) {
> > > +	case IIO_CHAN_INFO_RAW:
> > > +		ret = adxl372_read_axis(st, chan->address);
> > > +		if (ret < 0)
> > > +			return ret;
> > > +
> > > +		*val = sign_extend32(ret >> chan->scan_type.shift,
> > > +				?????chan->scan_type.realbits - 1);
> > > +		return IIO_VAL_INT;
> > > +	case IIO_CHAN_INFO_SCALE:
> > > +		*val = 0;
> > > +		*val2 = ADXL372_USCALE;
> > > +		return IIO_VAL_INT_PLUS_MICRO;
> > > +	default:
> > > +		return -EINVAL;
> > > +	}
> > > +}
> > > +
> > > +static const struct iio_info adxl372_info = {
> > > +	.read_raw = adxl372_read_raw,
> > > +	.debugfs_reg_access = &adxl372_reg_access,
> > > +};
> > > +
> > > +static const struct regmap_config adxl372_spi_regmap_config = {
> > > +	.reg_bits = 7,
> > > +	.pad_bits = 1,
> > > +	.val_bits = 8,
> > > +	.read_flag_mask = BIT(0),
> > > +};
> > > +
> > > +static int adxl372_probe(struct spi_device *spi)
> > > +{
> > > +	struct iio_dev *indio_dev;
> > > +	struct adxl372_state *st;
> > > +	struct regmap *regmap;
> > > +	int ret;
> > > +
> > > +	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> > > +	if (!indio_dev)
> > > +		return -ENOMEM;
> > > +
> > > +	st = iio_priv(indio_dev);
> > > +	spi_set_drvdata(spi, indio_dev);
> > > +
> > > +	st->spi = spi;
> > > +
> > > +	regmap = devm_regmap_init_spi(spi,
> > > &adxl372_spi_regmap_config);
> > > +	if (IS_ERR(regmap))
> > > +		return PTR_ERR(regmap);
> > > +
> > > +	st->regmap = regmap;
> > > +
> > > +	indio_dev->channels = adxl372_channels;
> > > +	indio_dev->num_channels = ARRAY_SIZE(adxl372_channels);
> > > +	indio_dev->dev.parent = &spi->dev;
> > > +	indio_dev->name = spi_get_device_id(spi)->name;
> > > +	indio_dev->info = &adxl372_info;
> > > +	indio_dev->modes = INDIO_DIRECT_MODE;
> > > +
> > > +	ret = adxl372_setup(st);
> > > +	if (ret < 0) {
> > > +		dev_err(&st->spi->dev, "ADXL372 setup failed\n");
> > > +		return ret;
> > > +	}
> > > +
> > > +	return devm_iio_device_register(&st->spi->dev, indio_dev);
> > > +}
> > > +
> > > +static const struct spi_device_id adxl372_id[] = {
> > > +	{ "adxl372", 0 },
> > > +	{}
> > > +};
> > > +MODULE_DEVICE_TABLE(spi, adxl372_id);
> > > +
> > > +static struct spi_driver adxl372_driver = {
> > > +	.driver = {
> > > +		.name = KBUILD_MODNAME,
> > > +	},
> > > +	.probe = adxl372_probe,
> > > +	.id_table = adxl372_id,
> > > +};
> > > +
> > > +module_spi_driver(adxl372_driver);
> > > +
> > > +MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
> > > +MODULE_DESCRIPTION("Analog Devices ADXL372 3-axis accelerometer
> > > driver");
> > > +MODULE_LICENSE("GPL v2");  
> > 
> >