Re: [PATCH 2/2] staging: iio: accel: adis16240: move out of staging

Ardelean, Alexandru
2019-09-09T05:54:34Z

On Sun, 2019-09-08 at 12:09 +0100, Jonathan Cameron wrote:
> On Mon, 2 Sep 2019 13:26:02 +0000
> "Ardelean, Alexandru" <alexandru.Ardelean@analog.com> wrote:
>
> > On Sun, 2019-09-01 at 21:59 -0300, Rodrigo Carvalho wrote:
> > > Move ADIS16240 driver from staging to mainline.
> > >
> > > The ADIS16240 is a fully integrated digital shock detection
> > > and recorder system.
> >
> > Hey,
> >
> > Comments inline.
> >
> > I'll probably take a look in the next days again.
> > There seem to be some ABI/sysfs attributes that need to be resolved before moving this out of staging.
>
> Absolutely. It is a 'new' type of device so there are definitely some
> corners that need discussing before we move out of staging and commit
> to maintaining the ABI moving forwards.
>
> That is the real reason this driver was still in staging! No one
> had been through the process of proposing the ABI and responding to
> questions etc.
>
> The issue with impact sensors has always been that they don't really fit
> our normal model for buffers or triggers.
>
> So normally a trigger (if exposed in IIO) is used as one trigger
> causes 1 set of samples (so like a frame trigger for a camera).
>
> These devices tend to work in a mode where one trigger causes data
> to be captured for a period of time. In this part that's the event
> recorder function
>
> No one is realistically going to buy an impact sensor to just use it
> as an accelerometer which is what this driver is currently doing.
> I suppose we could just leave support in that form for now, but
> I'm no sure how much use it is to anyone.
>
> Analog Devices people, worth working out how to support the event
> recorder? For that someone needs to have hardware as it is complex
> to say the least!

Worth it: yes.
But we don't have any resources to allocate for this [at this point in time].

>
> We could move it out but might be worth adding a comment somewhere
> saying this only really supports direct access to channels, and
> not the event recorder functionality.
>

I guess, I would vote for leaving it in staging.
It's also a way to mark it as a work-in-progress/not-done/still-needs-something kind of thing.
If we move it now, it gets the status of "everything-resolved" which is not yet the case.

Thanks for the insight/background info.
Much of it was discussed before my time.

>
> Jonathan

Alex

>
>
> > > Signed-off-by: Rodrigo Ribeiro Carvalho <rodrigorsdc@gmail.com>
> > > ---
> > > drivers/iio/accel/Kconfig | 12 +
> > > drivers/iio/accel/Makefile | 1 +
> > > drivers/iio/accel/adis16240.c | 454 ++++++++++++++++++++++++++
> > > drivers/staging/iio/accel/Kconfig | 12 -
> > > drivers/staging/iio/accel/Makefile | 1 -
> > > drivers/staging/iio/accel/adis16240.c | 454 --------------------------
> > > 6 files changed, 467 insertions(+), 467 deletions(-)
> > > create mode 100644 drivers/iio/accel/adis16240.c
> > > delete mode 100644 drivers/staging/iio/accel/adis16240.c
> >
> > Looks like MAINTAINERS file also needs to be updated, also with the DT bindings file.
> > I think checkpatch usually complains about these.
> >
> > > diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
> > > index d4ef35aeb579..91fd8741c95f 100644
> > > --- a/drivers/iio/accel/Kconfig
> > > +++ b/drivers/iio/accel/Kconfig
> > > @@ -30,6 +30,18 @@ config ADIS16209
> > > To compile this driver as a module, say M here: the module will be
> > > called adis16209.
> > >
> > > +config ADIS16240
> > > + tristate "Analog Devices ADIS16240 Programmable Impact Sensor and Recorder"
> > > + depends on SPI
> > > + select IIO_ADIS_LIB
> > > + select IIO_ADIS_LIB_BUFFER if IIO_BUFFER
> > > + help
> > > + Say Y here to build support for Analog Devices adis16240 programmable
> > > + impact Sensor and recorder.
> > > +
> > > + To compile this driver as a module, say M here: the module will be
> > > + called adis16240.
> > > +
> > > config ADXL345
> > > tristate
> > >
> > > diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
> > > index 56bd0215e0d4..f7e025a86dd9 100644
> > > --- a/drivers/iio/accel/Makefile
> > > +++ b/drivers/iio/accel/Makefile
> > > @@ -6,6 +6,7 @@
> > > # When adding new entries keep the list in alphabetical order
> > > obj-$(CONFIG_ADIS16201) += adis16201.o
> > > obj-$(CONFIG_ADIS16209) += adis16209.o
> > > +obj-$(CONFIG_ADIS16240) += adis16240.o
> > > obj-$(CONFIG_ADXL345) += adxl345_core.o
> > > obj-$(CONFIG_ADXL345_I2C) += adxl345_i2c.o
> > > obj-$(CONFIG_ADXL345_SPI) += adxl345_spi.o
> > > diff --git a/drivers/iio/accel/adis16240.c b/drivers/iio/accel/adis16240.c
> > > new file mode 100644
> > > index 000000000000..82099db4bf0c
> > > --- /dev/null
> > > +++ b/drivers/iio/accel/adis16240.c
> > > @@ -0,0 +1,454 @@
> > > +// SPDX-License-Identifier: GPL-2.0+
> > > +/*
> > > + * ADIS16240 Programmable Impact Sensor and Recorder driver
> > > + *
> > > + * Copyright 2010 Analog Devices Inc.
> > > + */
> > > +
> > > +#include <linux/interrupt.h>
> > > +#include <linux/irq.h>
> > > +#include <linux/gpio.h>
> > > +#include <linux/delay.h>
> > > +#include <linux/device.h>
> > > +#include <linux/kernel.h>
> > > +#include <linux/spi/spi.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/sysfs.h>
> > > +#include <linux/list.h>
> > > +#include <linux/module.h>
> > > +
> > > +#include <linux/iio/iio.h>
> > > +#include <linux/iio/sysfs.h>
> > > +#include <linux/iio/buffer.h>
> > > +#include <linux/iio/imu/adis.h>
> > > +
> > > +#define ADIS16240_STARTUP_DELAY 220 /* ms */
> > > +
> > > +/* Flash memory write count */
> > > +#define ADIS16240_FLASH_CNT 0x00
> > > +
> > > +/* Output, power supply */
> > > +#define ADIS16240_SUPPLY_OUT 0x02
> > > +
> > > +/* Output, x-axis accelerometer */
> > > +#define ADIS16240_XACCL_OUT 0x04
> > > +
> > > +/* Output, y-axis accelerometer */
> > > +#define ADIS16240_YACCL_OUT 0x06
> > > +
> > > +/* Output, z-axis accelerometer */
> > > +#define ADIS16240_ZACCL_OUT 0x08
> > > +
> > > +/* Output, auxiliary ADC input */
> > > +#define ADIS16240_AUX_ADC 0x0A
> > > +
> > > +/* Output, temperature */
> > > +#define ADIS16240_TEMP_OUT 0x0C
> > > +
> > > +/* Output, x-axis acceleration peak */
> > > +#define ADIS16240_XPEAK_OUT 0x0E
> > > +
> > > +/* Output, y-axis acceleration peak */
> > > +#define ADIS16240_YPEAK_OUT 0x10
> > > +
> > > +/* Output, z-axis acceleration peak */
> > > +#define ADIS16240_ZPEAK_OUT 0x12
> > > +
> > > +/* Output, sum-of-squares acceleration peak */
> > > +#define ADIS16240_XYZPEAK_OUT 0x14
> > > +
> > > +/* Output, Capture Buffer 1, X and Y acceleration */
> > > +#define ADIS16240_CAPT_BUF1 0x16
> > > +
> > > +/* Output, Capture Buffer 2, Z acceleration */
> > > +#define ADIS16240_CAPT_BUF2 0x18
> > > +
> > > +/* Diagnostic, error flags */
> > > +#define ADIS16240_DIAG_STAT 0x1A
> > > +This looks like it could be converted to IIO_CHAN_INFO_SAMP_FREQ attribute.
> > > +/* Diagnostic, event counter */
> > > +#define ADIS16240_EVNT_CNTR 0x1C
> > > +
> > > +/* Diagnostic, check sum value from firmware test */
> > > +#define ADIS16240_CHK_SUM 0x1E
> > > +
> > > +/* Calibration, x-axis acceleration offset adjustment */
> > > +#define ADIS16240_XACCL_OFF 0x20
> > > +
> > > +/* Calibration, y-axis acceleration offset adjustment */
> > > +#define ADIS16240_YACCL_OFF 0x22
> > > +
> > > +/* Calibration, z-axis acceleration offset adjustment */
> > > +#define ADIS16240_ZACCL_OFF 0x24
> > > +This looks like it could be converted to IIO_CHAN_INFO_SAMP_FREQ attribute.
> > > +/* Clock, hour and minute */
> > > +#define ADIS16240_CLK_TIME 0x2E
> > > +
> > > +/* Clock, month and day */
> > > +#define ADIS16240_CLK_DATE 0x30
> > > +
> > > +/* Clock, year */
> > > +#define ADIS16240_CLK_YEAR 0x32
> > > +
> > > +/* Wake-up setting, hour and minute */
> > > +#define ADIS16240_WAKE_TIME 0x34
> > > +
> > > +/* Wake-up setting, month and day */
> > > +#define ADIS16240_WAKE_DATE 0x36
> > > +
> > > +/* Alarm 1 amplitude threshold */
> > > +#define ADIS16240_ALM_MAG1 0x38
> > > +
> > > +/* Alarm 2 amplitude threshold */
> > > +#define ADIS16240_ALM_MAG2 0x3A
> > > +
> > > +/* Alarm control */
> > > +#define ADIS16240_ALM_CTRL 0x3C
> > > +
> > > +/* Capture, external trigger control */
> > > +#define ADIS16240_XTRIG_CTRL 0x3E
> > > +
> > > +/* Capture, address pointer */
> > > +#define ADIS16240_CAPT_PNTR 0x40
> > > +
> > > +/* Capture, configuration and control */
> > > +#define ADIS16240_CAPT_CTRL 0x42
> > > +
> > > +/* General-purpose digital input/output control */
> > > +#define ADIS16240_GPIO_CTRL 0x44
> > > +
> > > +/* Miscellaneous control */
> > > +#define ADIS16240_MSC_CTRL 0x46
> > > +
> > > +/* Internal sample period (rate) control */
> > > +#define ADIS16240_SMPL_PRD 0x48
> > > +
> > > +/* System command */
> > > +#define ADIS16240_GLOB_CMD 0x4A
> > > +
> > > +/* MSC_CTRL */
> > > +
> > > +/* Enables sum-of-squares output (XYZPEAK_OUT) */
> > > +#define ADIS16240_MSC_CTRL_XYZPEAK_OUT_EN BIT(15)
> > > +
> > > +/* Enables peak tracking output (XPEAK_OUT, YPEAK_OUT, and ZPEAK_OUT) */
> > > +#define ADIS16240_MSC_CTRL_X_Y_ZPEAK_OUT_EN BIT(14)
> > > +
> > > +/* Self-test enable: 1 = apply electrostatic force, 0 = disabled */
> > > +#define ADIS16240_MSC_CTRL_SELF_TEST_EN BIT(8)
> > > +
> > > +/* Data-ready enable: 1 = enabled, 0 = disabled */
> > > +#define ADIS16240_MSC_CTRL_DATA_RDY_EN BIT(2)
> > > +
> > > +/* Data-ready polarity: 1 = active high, 0 = active low */
> > > +#define ADIS16240_MSC_CTRL_ACTIVE_HIGH BIT(1)
> > > +
> > > +/* Data-ready line selection: 1 = DIO2, 0 = DIO1 */
> > > +#define ADIS16240_MSC_CTRL_DATA_RDY_DIO2 BIT(0)
> > > +
> > > +/* DIAG_STAT */
> > > +
> > > +/* Alarm 2 status: 1 = alarm active, 0 = alarm inactive */
> > > +#define ADIS16240_DIAG_STAT_ALARM2 BIT(9)
> > > +
> > > +/* Alarm 1 status: 1 = alarm active, 0 = alarm inactive */
> > > +#define ADIS16240_DIAG_STAT_ALARM1 BIT(8)
> > > +
> > > +/* Capture buffer full: 1 = capture buffer is full */
> > > +#define ADIS16240_DIAG_STAT_CPT_BUF_FUL BIT(7)
> > > +
> > > +/* Flash test, checksum flag: 1 = mismatch, 0 = match */
> > > +#define ADIS16240_DIAG_STAT_CHKSUM BIT(6)
> > > +
> > > +/* Power-on, self-test flag: 1 = failure, 0 = pass */
> > > +#define ADIS16240_DIAG_STAT_PWRON_FAIL_BIT 5
> > > +
> > > +/* Power-on self-test: 1 = in-progress, 0 = complete */
> > > +#define ADIS16240_DIAG_STAT_PWRON_BUSY BIT(4)
> > > +
> > > +/* SPI communications failure */
> > > +#define ADIS16240_DIAG_STAT_SPI_FAIL_BIT 3
> > > +
> > > +/* Flash update failure */
> > > +#define ADIS16240_DIAG_STAT_FLASH_UPT_BIT 2
> > > +
> > > +/* Power supply above 3.625 V */
> > > +#define ADIS16240_DIAG_STAT_POWER_HIGH_BIT 1
> > > +
> > > + /* Power supply below 2.225 V */
> > > +#define ADIS16240_DIAG_STAT_POWER_LOW_BIT 0
> > > +
> > > +/* GLOB_CMD */
> > > +
> > > +#define ADIS16240_GLOB_CMD_RESUME BIT(8)
> > > +#define ADIS16240_GLOB_CMD_SW_RESET BIT(7)
> > > +#define ADIS16240_GLOB_CMD_STANDBY BIT(2)
> > > +
> > > +#define ADIS16240_ERROR_ACTIVE BIT(14)
> > > +
> > > +/* At the moment triggers are only used for ring buffer
> > > + * filling. This may change!
> > > + */
> > > +
> > > +enum adis16240_scan {
> > > + ADIS16240_SCAN_ACC_X,
> > > + ADIS16240_SCAN_ACC_Y,
> > > + ADIS16240_SCAN_ACC_Z,
> > > + ADIS16240_SCAN_SUPPLY,
> > > + ADIS16240_SCAN_AUX_ADC,
> > > + ADIS16240_SCAN_TEMP,
> > > +};
> > > +
> > > +static ssize_t adis16240_spi_read_signed(struct device *dev,
> > > + struct device_attribute *attr,
> > > + char *buf,
> > > + unsigned int bits)
> > > +{
> > > + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> > > + struct adis *st = iio_priv(indio_dev);
> > > + int ret;
> > > + s16 val = 0;
> > > + unsigned int shift = 16 - bits;
> > > + struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> > > +
> > > + ret = adis_read_reg_16(st,
> > > + this_attr->address, (u16 *)&val);
>
> Check for odd line breaks. That looks like it'll fit under 80 chars
> just fine.
>
> > > + if (ret)
> > > + return ret;
> > > +
> > > + if (val & ADIS16240_ERROR_ACTIVE)
> > > + adis_check_status(st);
> > > +
> > > + val = (s16)(val << shift) >> shift;
>
> Use sign_extend32 (added after this driver I think!)
>
> > > + return sprintf(buf, "%d\n", val);
> > > +}
> > > +
> > > +static ssize_t adis16240_read_12bit_signed(struct device *dev,
> > > + struct device_attribute *attr,
> > > + char *buf)
> > > +{
> > > + return adis16240_spi_read_signed(dev, attr, buf, 12);
> > > +}
> > > +
> > > +static IIO_DEVICE_ATTR(in_accel_xyz_squared_peak_raw, 0444,
> > > + adis16240_read_12bit_signed, NULL,
> > > + ADIS16240_XYZPEAK_OUT);
> > > +
> > > +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("4096");
> > > +
> > > +static const u8 adis16240_addresses[][2] = {
> > > + [ADIS16240_SCAN_ACC_X] = { ADIS16240_XACCL_OFF, ADIS16240_XPEAK_OUT },
> > > + [ADIS16240_SCAN_ACC_Y] = { ADIS16240_YACCL_OFF, ADIS16240_YPEAK_OUT },
> > > + [ADIS16240_SCAN_ACC_Z] = { ADIS16240_ZACCL_OFF, ADIS16240_ZPEAK_OUT },
> > > +};
> > > +
> > > +static int adis16240_read_raw(struct iio_dev *indio_dev,
> > > + struct iio_chan_spec const *chan,
> > > + int *val, int *val2,
> > > + long mask)
> > > +{
> > > + struct adis *st = iio_priv(indio_dev);
> > > + int ret;
> > > + u8 addr;
> > > + s16 val16;
> > > +
> > > + switch (mask) {
> > > + case IIO_CHAN_INFO_RAW:
> > > + return adis_single_conversion(indio_dev, chan,
> > > + ADIS16240_ERROR_ACTIVE, val);
> > > + case IIO_CHAN_INFO_SCALE:
> > > + switch (chan->type) {
> > > + case IIO_VOLTAGE:
> > > + if (chan->channel == 0) {
> > > + *val = 4;
> > > + *val2 = 880000; /* 4.88 mV */
> > > + return IIO_VAL_INT_PLUS_MICRO;
> > > + }
> > > + return -EINVAL;
> > > + case IIO_TEMP:
> > > + *val = 244; /* 0.244 C */
> > > + *val2 = 0;
> >
> > This looks like a bug in the original driver.
> > I think *val = 0, and *val2 = 244 ?
> >
> > > + return IIO_VAL_INT_PLUS_MICRO;
> > > + case IIO_ACCEL:
> > > + *val = 0;
> > > + *val2 = IIO_G_TO_M_S_2(51400); /* 51.4 mg */
> > > + return IIO_VAL_INT_PLUS_MICRO;
> > > + default:
> > > + return -EINVAL;
> > > + }
> > > + break;
> > > + case IIO_CHAN_INFO_PEAK_SCALE:
> > > + *val = 0;
> > > + *val2 = IIO_G_TO_M_S_2(51400); /* 51.4 mg */
> > > + return IIO_VAL_INT_PLUS_MICRO;
> > > + case IIO_CHAN_INFO_OFFSET:
> > > + *val = 25000 / 244 - 0x133; /* 25 C = 0x133 */
> > > + return IIO_VAL_INT;
> > > + case IIO_CHAN_INFO_CALIBBIAS:
> > > + addr = adis16240_addresses[chan->scan_index][0];
> > > + ret = adis_read_reg_16(st, addr, &val16);
> > > + if (ret)
> > > + return ret;
> > > + *val = sign_extend32(val16, 9);
> > > + return IIO_VAL_INT;
> > > + case IIO_CHAN_INFO_PEAK:
> > > + addr = adis16240_addresses[chan->scan_index][1];
> > > + ret = adis_read_reg_16(st, addr, &val16);
> > > + if (ret)
> > > + return ret;
> > > + *val = sign_extend32(val16, 9);
> > > + return IIO_VAL_INT;
> > > + }
> > > + return -EINVAL;
> > > +}
> > > +
> > > +static int adis16240_write_raw(struct iio_dev *indio_dev,
> > > + struct iio_chan_spec const *chan,
> > > + int val,
> > > + int val2,
> > > + long mask)
> > > +{
> > > + struct adis *st = iio_priv(indio_dev);
> > > + u8 addr;
> > > +
> > > + switch (mask) {
> > > + case IIO_CHAN_INFO_CALIBBIAS:
> > > + addr = adis16240_addresses[chan->scan_index][0];
> > > + return adis_write_reg_16(st, addr, val & GENMASK(9, 0));
> > > + }
> > > + return -EINVAL;
> > > +}
> > > +
> > > +static const struct iio_chan_spec adis16240_channels[] = {
> > > + ADIS_SUPPLY_CHAN(ADIS16240_SUPPLY_OUT, ADIS16240_SCAN_SUPPLY, 0, 10),
> > > + ADIS_AUX_ADC_CHAN(ADIS16240_AUX_ADC, ADIS16240_SCAN_AUX_ADC, 0, 10),
> > > + ADIS_ACCEL_CHAN(X, ADIS16240_XACCL_OUT, ADIS16240_SCAN_ACC_X,
> > > + BIT(IIO_CHAN_INFO_CALIBBIAS) | BIT(IIO_CHAN_INFO_PEAK),
> > > + 0, 10),
> > > + ADIS_ACCEL_CHAN(Y, ADIS16240_YACCL_OUT, ADIS16240_SCAN_ACC_Y,
> > > + BIT(IIO_CHAN_INFO_CALIBBIAS) | BIT(IIO_CHAN_INFO_PEAK),
> > > + 0, 10),
> > > + ADIS_ACCEL_CHAN(Z, ADIS16240_ZACCL_OUT, ADIS16240_SCAN_ACC_Z,
> > > + BIT(IIO_CHAN_INFO_CALIBBIAS) | BIT(IIO_CHAN_INFO_PEAK),
> > > + 0, 10),
> > > + ADIS_TEMP_CHAN(ADIS16240_TEMP_OUT, ADIS16240_SCAN_TEMP, 0, 10),
> > > + IIO_CHAN_SOFT_TIMESTAMP(6)
> > > +};
> > > +
> > > +static struct attribute *adis16240_attributes[] = {
> > > + &iio_dev_attr_in_accel_xyz_squared_peak_raw.dev_attr.attr,
> >
> > This one looks a bit weird/rare.
> > I am not sure about it's use-case/need right now (at this point in time).
> >
> > Maybe we could just drop it?
> > Since I did not write the initial driver, I don't know yet what it was supposed to be/do.
>
> For an impact sensor it's a fairly useful thing I suspect as it is giving the maximum
> acceleration in any direction that occured (once you square root it in userspace.)
>
> > In any case, if we want to add it, it looks like it needs an ABI documentation.
>
> Agreed. Needs docs. We actually have a modifier for it so can be handled
> as a channel. IIO_MOD_SUM_SQUARED_X_Y_Z :)
>
>
> >
> > > + &iio_const_attr_sampling_frequency_available.dev_attr.attr,
> >
> > This looks like it could be converted to IIO_CHAN_INFO_SAMP_FREQ attribute.
> >
> >
> > > + NULL
> > > +};
> > > +
> > > +static const struct attribute_group adis16240_attribute_group = {
> > > + .attrs = adis16240_attributes,
> > > +};
> > > +
> > > +static const struct iio_info adis16240_info = {
> > > + .attrs = &adis16240_attribute_group,
> > > + .read_raw = adis16240_read_raw,
> > > + .write_raw = adis16240_write_raw,
> > > + .update_scan_mode = adis_update_scan_mode,
> > > +};
> > > +
> > > +static const char * const adis16240_status_error_msgs[] = {
> > > + [ADIS16240_DIAG_STAT_PWRON_FAIL_BIT] = "Power on, self-test failed",
> > > + [ADIS16240_DIAG_STAT_SPI_FAIL_BIT] = "SPI failure",
> > > + [ADIS16240_DIAG_STAT_FLASH_UPT_BIT] = "Flash update failed",
> > > + [ADIS16240_DIAG_STAT_POWER_HIGH_BIT] = "Power supply above 3.625V",
> > > + [ADIS16240_DIAG_STAT_POWER_LOW_BIT] = "Power supply below 2.225V",
> > > +};
> > > +
> > > +static const struct adis_data adis16240_data = {
> > > + .write_delay = 35,
> > > + .read_delay = 35,
> > > + .msc_ctrl_reg = ADIS16240_MSC_CTRL,
> > > + .glob_cmd_reg = ADIS16240_GLOB_CMD,
> > > + .diag_stat_reg = ADIS16240_DIAG_STAT,
> > > +
> > > + .self_test_mask = ADIS16240_MSC_CTRL_SELF_TEST_EN,
> > > + .self_test_no_autoclear = true,
> > > + .startup_delay = ADIS16240_STARTUP_DELAY,
> > > +
> > > + .status_error_msgs = adis16240_status_error_msgs,
> > > + .status_error_mask = BIT(ADIS16240_DIAG_STAT_PWRON_FAIL_BIT) |
> > > + BIT(ADIS16240_DIAG_STAT_SPI_FAIL_BIT) |
> > > + BIT(ADIS16240_DIAG_STAT_FLASH_UPT_BIT) |
> > > + BIT(ADIS16240_DIAG_STAT_POWER_HIGH_BIT) |
> > > + BIT(ADIS16240_DIAG_STAT_POWER_LOW_BIT),
> > > +};
> > > +
> > > +static int adis16240_probe(struct spi_device *spi)
> > > +{
> > > + int ret;
> > > + struct adis *st;
> > > + struct iio_dev *indio_dev;
> > > +
> > > + /* setup the industrialio driver allocated elements */
>
> I would review comments and decide whether they actually add anything.
> This one for example - I'm not convinced!
>
> > > + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> > > + if (!indio_dev)
> > > + return -ENOMEM;
> > > + st = iio_priv(indio_dev);
> > > + /* this is only used for removal purposes */
> > > + spi_set_drvdata(spi, indio_dev);
> > > +
> > > + indio_dev->name = spi->dev.driver->name;
> > > + indio_dev->dev.parent = &spi->dev;
> > > + indio_dev->info = &adis16240_info;
> > > + indio_dev->channels = adis16240_channels;
> > > + indio_dev->num_channels = ARRAY_SIZE(adis16240_channels);
> > > + indio_dev->modes = INDIO_DIRECT_MODE;
> > > +
> > > + ret = adis_init(st, indio_dev, spi, &adis16240_data);
> > > + if (ret)
> > > + return ret;
>
> Might be nice to look at adding some white space after error handling
> blocks like this. A blank line in locations like this make it
> easier for the eye to follow the code.
>
> > > + ret = adis_setup_buffer_and_trigger(st, indio_dev, NULL);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + /* Get the device into a sane initial state */
> > > + ret = adis_initial_startup(st);
> > > + if (ret)
> > > + goto error_cleanup_buffer_trigger;
> > > + ret = iio_device_register(indio_dev);
> > > + if (ret)
> > > + goto error_cleanup_buffer_trigger;
> > > + return 0;
> > > +
> > > +error_cleanup_buffer_trigger:
> > > + adis_cleanup_buffer_and_trigger(st, indio_dev);
> > > + return ret;
> > > +}
> > > +
> > > +static int adis16240_remove(struct spi_device *spi)
> > > +{
> > > + struct iio_dev *indio_dev = spi_get_drvdata(spi);
> > > + struct adis *st = iio_priv(indio_dev);
> > > +
> > > + iio_device_unregister(indio_dev);
> > > + adis_cleanup_buffer_and_trigger(st, indio_dev);
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static const struct of_device_id adis16240_of_match[] = {
> > > + { .compatible = "adi,adis16240" },
> > > + { },
> > > +};
> > > +MODULE_DEVICE_TABLE(of, adis16240_of_match);
> > > +
> > > +static struct spi_driver adis16240_driver = {
> > > + .driver = {
> > > + .name = "adis16240",
> > > + .of_match_table = adis16240_of_match,
> > > + },
> > > + .probe = adis16240_probe,
> > > + .remove = adis16240_remove,
> > > +};
> > > +module_spi_driver(adis16240_driver);
> > > +
> > > +MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
> > > +MODULE_DESCRIPTION("Analog Devices Programmable Impact Sensor and Recorder");
> > > +MODULE_LICENSE("GPL v2");
> > > +MODULE_ALIAS("spi:adis16240");
> ...