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Message-ID: <ea58851c-3bf1-ab51-0771-6844ed53b892@vaisala.com>
Date: Mon, 19 Apr 2021 16:34:35 +0300
From: Tomas Melin <tomas.melin@...sala.com>
To: Jonathan Cameron <jic23@...nel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@...wei.com>,
devicetree@...r.kernel.org, linux-iio@...r.kernel.org,
linux-kernel@...r.kernel.org, aardelean@...iqon.com,
Alexandru Ardelean <ardeleanalex@...il.com>
Subject: Re: [PATCH 2/2] iio: accel: Add driver for Murata SCA3300
accelerometer
Hi,
On 4/18/21 1:03 PM, Jonathan Cameron wrote:
> On Fri, 16 Apr 2021 15:21:14 +0300
> Tomas Melin <tomas.melin@...sala.com> wrote:
>
>> Updated email-address for Alexandru.
>>
>>
>> On 4/16/21 3:17 PM, Tomas Melin wrote:
>>> On 4/15/21 11:41 AM, Tomas Melin wrote:
>>>
>>>> While working on updates I did notice something new which I cannot
>>>>
>>>> reproduce on older (5.10.17 kernel) version. If compiling this as a
>>>> module, getting error while
>>>>
>>>> unloading module:
>>>>
>>>> [ 40.200084] Unable to handle kernel NULL pointer dereference at
>>>> virtual address 00000104
>>>> ...
>>>>
>>>> [ 40.510054] Backtrace:
>>>> [ 40.512502] [<c06c5e0c>] (iio_device_ioctl_handler_unregister)
>>>> from [<c06ca8c4>] (iio_buffers_free_sysfs_and_mask+0x2c/0x6c)
>>>> [ 40.523735] [<c06ca898>] (iio_buffers_free_sysfs_and_mask) from
>>>> [<c06c4a18>] (iio_device_unregister+0xa8/0xac)
>>>> [ 40.533746] r5:c1811228 r4:c1811000
>>>> [ 40.537318] [<c06c4970>] (iio_device_unregister) from [<c06c4a38>]
>>>> (devm_iio_device_unreg+0x1c/0x20)
>>>> [ 40.546461] r5:c2415000 r4:c25bab80
>>>> [ 40.550025] [<c06c4a1c>] (devm_iio_device_unreg) from [<c0556820>]
>>>> (release_nodes+0x1c0/0x1f0)
>>>> [ 40.558654] [<c0556660>] (release_nodes) from [<c0556bb0>]
>>>> (devres_release_all+0x40/0x60)
>>>> [ 40.566847] r10:00000081 r9:c2350000 r8:c0100264 r7:00000081
>>>> r6:bf00c010 r5:c19be000
>>>> [ 40.574669] r4:c1a91c00
>>>> [ 40.577194] [<c0556b70>] (devres_release_all) from [<c055216c>]
>>>> (device_release_driver_internal+0x120/0x1cc)
>>>> [ 40.587031] r5:c19be000 r4:c1a91c00
>>>> [ 40.590596] [<c055204c>] (device_release_driver_internal) from
>>>> [<c05522b4>] (driver_detach+0x54/0x90)
>>>> [ 40.599828] r7:00000081 r6:00000000 r5:bf00c010 r4:c1a91c00
>>>> [ 40.605482] [<c0552260>] (driver_detach) from [<c0550ba4>]
>>>> (bus_remove_driver+0x5c/0xb0)
>>>> [ 40.613583] r5:00000800 r4:bf00c010
>>>> [ 40.617148] [<c0550b48>] (bus_remove_driver) from [<c0552c38>]
>>>> (driver_unregister+0x38/0x5c)
>>>> [ 40.625596] r5:00000800 r4:bf00c010
>>>> [ 40.629161] [<c0552c00>] (driver_unregister) from [<bf00a760>]
>>>> (sca3300_driver_exit+0x14/0x8b4 [sca3300])
>>>> [ 40.638747] r5:00000800 r4:bf00c080
>>>> [ 40.642311] [<bf00a74c>] (sca3300_driver_exit [sca3300]) from
>>>> [<c01c06f0>] (sys_delete_module+0x16c/0x238)
>>>> [ 40.651990] [<c01c0584>] (sys_delete_module) from [<c0100244>]
>>>> (__sys_trace_return+0x0/0x1c)
>>>> [ 40.660435] Exception stack(0xc2351fa8 to 0xc2351ff0)
>>>> [ 40.665484] 1fa0: 0050e5a8 00000000 0050e5e4
>>>> 00000800 081d4b00 bec18af4
>>>> [ 40.673661] 1fc0: 0050e5a8 00000000 bec18b50 00000081 bec18e51
>>>> 0050e190 00000001 bec18d3c
>>>> [ 40.681834] 1fe0: 0050cf70 bec18afc 004f1ec8 b6ecb27c
>>>> [ 40.686887] r6:bec18b50 r5:00000000 r4:0050e5a8
>>>> [ 40.691507] Code: e8bd4000 e1c020d0 e3a0cc01 e3001122 (e5823004)
>>>> [ 40.707675] ---[ end trace 189882b050077333 ]---
>>>>
>>>> This happens when building against linux-next
>>>> 5.12.0-rc6-next-20210409. I'm failing to see what is wrong. Any ideas?
>>>>
>>>> Thanks,
>>>>
>>>> Tomas
>>>
>>> Tested further that for this driver, loading and unloading as module
>>> works fine until commit:
>>>
>>> commit f73f7f4da581875f9b1f2fb8ebd1ab15ed634488
>>> Author: Alexandru Ardelean <alexandru.ardelean@...log.com>
>>> Date: Mon Feb 15 12:40:39 2021 +0200
>>>
>>> iio: buffer: add ioctl() to support opening extra buffers for IIO
>>> device
>>>
>>>
>>> Any thoughts what causes this issue?
> Is this still happening after fixing the ordering in probe / remove?
> (devm_iio_triggered_buffer_setup() being easiest way)
>
> As driver currently stands it's calling iio_triggered_buffer_cleanup
> before the managed cleanup of the iio_device_register() call. That
> should never happen so would be where I'd look for problems here.
>
> It is possible Alex's work is relying on that ordering being correct
> a little more than we previously were. I could be wrong though
> and could be something else going on!
>
> Jonathan
>
> +CC Alex's other email address.
This is still happening with v3 of driver patchset, which uses only devm_*
versions in probing. v5.12-rc7 works ok, I'm currently only seeing this
using linux-next.
Thanks,
Tomas
>>> Thanks,
>>>
>>> Tomas
>>>
>>>
>>>
>>>>
>>>>>
>>>>>> ---
>>>>>> drivers/iio/accel/Kconfig | 13 ++
>>>>>> drivers/iio/accel/Makefile | 1 +
>>>>>> drivers/iio/accel/sca3300.c | 434
>>>>>> ++++++++++++++++++++++++++++++++++++
>>>>>> 3 files changed, 448 insertions(+)
>>>>>> create mode 100644 drivers/iio/accel/sca3300.c
>>>>>>
>>>>>> diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
>>>>>> index cceda3cecbcf..0dbf7b648e8a 100644
>>>>>> --- a/drivers/iio/accel/Kconfig
>>>>>> +++ b/drivers/iio/accel/Kconfig
>>>>>> @@ -450,6 +450,19 @@ config SCA3000
>>>>>> To compile this driver as a module, say M here: the module
>>>>>> will be
>>>>>> called sca3000.
>>>>>> +config SCA3300
>>>>>> + tristate "Murata SCA3300 3-Axis Accelerometer Driver"
>>>>>> + depends on SPI
>>>>>> + select CRC8
>>>>>> + select IIO_BUFFER
>>>>>> + select IIO_TRIGGERED_BUFFER
>>>>>> + help
>>>>>> + Say yes here to build support for Murata SCA3300 3-Axis
>>>>>> + accelerometer.
>>>>>> +
>>>>>> + To compile this driver as a module, choose M here: the
>>>>>> module will be
>>>>>> + called sca3300.
>>>>>> +
>>>>>> config STK8312
>>>>>> tristate "Sensortek STK8312 3-Axis Accelerometer Driver"
>>>>>> depends on I2C
>>>>>> diff --git a/drivers/iio/accel/Makefile b/drivers/iio/accel/Makefile
>>>>>> index 32cd1342a31a..4b56527a2b97 100644
>>>>>> --- a/drivers/iio/accel/Makefile
>>>>>> +++ b/drivers/iio/accel/Makefile
>>>>>> @@ -50,6 +50,7 @@ obj-$(CONFIG_MXC4005) += mxc4005.o
>>>>>> obj-$(CONFIG_MXC6255) += mxc6255.o
>>>>>> obj-$(CONFIG_SCA3000) += sca3000.o
>>>>>> +obj-$(CONFIG_SCA3300) += sca3300.o
>>>>>> obj-$(CONFIG_STK8312) += stk8312.o
>>>>>> obj-$(CONFIG_STK8BA50) += stk8ba50.o
>>>>>> diff --git a/drivers/iio/accel/sca3300.c b/drivers/iio/accel/sca3300.c
>>>>>> new file mode 100644
>>>>>> index 000000000000..112fb88ecd3a
>>>>>> --- /dev/null
>>>>>> +++ b/drivers/iio/accel/sca3300.c
>>>>>> @@ -0,0 +1,434 @@
>>>>>> +// SPDX-License-Identifier: GPL-2.0-only
>>>>>> +/*
>>>>>> + * Copyright (c) Vaisala Oyj. All rights reserved.
>>>>> Give a year for the copyright notice if you can.
>>>>>
>>>>>> + */
>>>>>> +#include <linux/crc8.h>
>>>>>> +#include <linux/delay.h>
>>>>>> +#include <linux/iio/buffer.h>
>>>>>> +#include <linux/iio/iio.h>
>>>>>> +#include <linux/iio/sysfs.h>
>>>>>> +#include <linux/iio/trigger_consumer.h>
>>>>>> +#include <linux/iio/triggered_buffer.h>
>>>>>> +#include <linux/kernel.h>
>>>>>> +#include <linux/module.h>
>>>>>> +#include <linux/spi/spi.h>
>>>>>> +
>>>>>> +#define SCA3300_ALIAS "sca3300"
>>>>>> +
>>>>>> +#define SCA3300_REG_STATUS 0x6
>>>>>> +#define SCA3300_REG_MODE 0xd
>>>>>> +#define SCA3300_REG_WHOAMI 0x10
>>>>>> +#define SCA3300_VALUE_SW_RESET 0x20
>>>>>> +#define SCA3300_CRC8_POLYNOMIAL 0x1d
>>>>>> +#define SCA3300_X_READ 0
>>>>> I wouldn't bother defining this.
>>>>>
>>>>>> +#define SCA3300_X_WRITE BIT(7)
>>>>> Even this one is something I'd just put inline with a comment.
>>>>>
>>>>>> +#define SCA3300_DEVICE_ID 0x51
>>>>>> +#define SCA3300_RS_ERROR 0x3
>>>>>> +
>>>>>> +enum sca3300_scan_indexes {
>>>>>> + SCA3300_ACC_X = 0,
>>>>>> + SCA3300_ACC_Y,
>>>>>> + SCA3300_ACC_Z,
>>>>>> + SCA3300_TEMP,
>>>>>> + SCA3300_TIMESTAMP,
>>>>>> +};
>>>>>> +
>>>>>> +#define SCA3300_ACCEL_CHANNEL(index, reg, axis) { \
>>>>>> + .type = IIO_ACCEL, \
>>>>>> + .address = reg, \
>>>>>> + .modified = 1, \
>>>>>> + .channel2 = IIO_MOD_##axis, \
>>>>>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
>>>>>> + BIT(IIO_CHAN_INFO_PROCESSED), \
>>>>> As mentioned below, don't provide PROCESSED. Userspace is better at
>>>>> handling the
>>>>> conversion so leave it to them.
>>>>>
>>>>>> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
>>>>>> + .scan_index = index, \
>>>>>> + .scan_type = { \
>>>>>> + .sign = 's', \
>>>>>> + .realbits = 16, \
>>>>>> + .storagebits = 16, \
>>>>>> + .shift = 0, \
>>>>>> + .endianness = IIO_CPU, \
>>>>>> + }, \
>>>>>> + }
>>>>>> +
>>>>>> +static const struct iio_chan_spec sca3300_channels[] = {
>>>>>> + SCA3300_ACCEL_CHANNEL(SCA3300_ACC_X, 0x1, X),
>>>>>> + SCA3300_ACCEL_CHANNEL(SCA3300_ACC_Y, 0x2, Y),
>>>>>> + SCA3300_ACCEL_CHANNEL(SCA3300_ACC_Z, 0x3, Z),
>>>>>> + {
>>>>>> + .type = IIO_TEMP,
>>>>>> + .address = 0x5,
>>>>>> + .scan_index = SCA3300_TEMP,
>>>>>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
>>>>>> + .scan_type = {
>>>>>> + .sign = 's',
>>>>>> + .realbits = 16,
>>>>>> + .storagebits = 16,
>>>>>> + .shift = 0,
>>>>>> + .endianness = IIO_CPU,
>>>>>> + },
>>>>>> + },
>>>>>> + IIO_CHAN_SOFT_TIMESTAMP(4),
>>>>>> +};
>>>>>> +
>>>>>> +static const int sca3300_accel_scale[] = {2700, 1350, 5400, 5400};
>>>>>> +
>>>>>> +static const unsigned long sca3300_scan_masks[] = {
>>>>>> + BIT(SCA3300_ACC_X) | BIT(SCA3300_ACC_Y) | BIT(SCA3300_ACC_Z) |
>>>>>> + BIT(SCA3300_TEMP),
>>>>>> + 0};
>>>>>> +
>>>>>> +/**
>>>>>> + * SCA3300 device data
>>>>> run scripts/kernel-doc over the file and fix the warnings + errors.
>>>>>
>>>>>> + *
>>>>>> + * @spi SPI device structure
>>>>>> + * @opmode Device operation mode
>>>>>> + * @lock Data buffer lock
>>>>>> + * @txbuf Transmit buffer
>>>>>> + * @rxbuf Receive buffer
>>>>>> + * @scan Triggered buffer. Four channel 16-bit data + 64-bit
>>>>>> timestamp
>>>>>> + */
>>>>>> +struct sca3300_data {
>>>>>> + struct spi_device *spi;
>>>>>> + u32 opmode;
>>>>>> + struct mutex lock;
>>>>>> + u8 txbuf[4];
>>>>>> + u8 rxbuf[4];
>>>>>> + struct {
>>>>>> + s16 channels[4];
>>>>>> + s64 ts __aligned(sizeof(s64));
>>>>>> + } scan;
>>>>>> +};
>>>>>> +
>>>>>> +DECLARE_CRC8_TABLE(sca3300_crc_table);
>>>>>> +
>>>>>> +static int sca3300_transfer(struct sca3300_data *sca_data, int *val)
>>>>>> +{
>>>>>> + struct spi_delay delay = {.value = 10, .unit =
>>>>>> SPI_DELAY_UNIT_USECS};
>>>>>> + int32_t ret;
>>>>>> + int rs;
>>>>>> + u8 crc;
>>>>>> + struct spi_transfer xfers[2] = {
>>>>>> + {
>>>>>> + .tx_buf = sca_data->txbuf,
>>>>>> + .rx_buf = NULL,
>>>>>> + .len = ARRAY_SIZE(sca_data->txbuf),
>>>>>> + .delay = delay,
>>>>>> + .cs_change = 1,
>>>>>> + },
>>>>>> + {
>>>>>> + .tx_buf = NULL,
>>>>>> + .rx_buf = sca_data->rxbuf,
>>>>>> + .len = ARRAY_SIZE(sca_data->rxbuf),
>>>>>> + .delay = delay,
>>>>>> + .cs_change = 0,
>>>>>> + }
>>>>>> + };
>>>>>> +
>>>>>> + /* inverted crc value as described in device data sheet */
>>>>>> + crc = ~crc8(sca3300_crc_table, &sca_data->txbuf[0], 3,
>>>>>> CRC8_INIT_VALUE);
>>>>>> + sca_data->txbuf[3] = crc;
>>>>>> +
>>>>>> + ret = spi_sync_transfer(sca_data->spi, xfers, 2);
>>>>> Use ARRAY_SIZE(xfers) instead of 2.
>>>>>
>>>>>> + if (ret < 0) {
>>>>>> + dev_err(&sca_data->spi->dev,
>>>>>> + "transfer error, error: %d\n", ret);
>>>>>> + return -EIO;
>>>>>> + }
>>>>>> +
>>>>>> + crc = ~crc8(sca3300_crc_table, &sca_data->rxbuf[0], 3,
>>>>>> CRC8_INIT_VALUE);
>>>>>> + if (sca_data->rxbuf[3] != crc) {
>>>>>> + dev_err(&sca_data->spi->dev, "CRC checksum mismatch");
>>>>>> + return -EIO;
>>>>>> + }
>>>>>> +
>>>>>> + /* get return status */
>>>>>> + rs = sca_data->rxbuf[0] & 0x03;
>>>>>> + if (rs == SCA3300_RS_ERROR)
>>>>>> + return rs;
>>>>>> +
>>>>>> + *val = (s16)(sca_data->rxbuf[2] | (sca_data->rxbuf[1] << 8));
>>>>> Preference for an unaligned endian conversion here and explicit sign
>>>>> extend e.g
>>>>> something like
>>>>>
>>>>> sign_extend32(get_unaligned_le16(&sca_data->rxbuf[1]), 15)
>>>>>
>>>>>> +
>>>>>> + return 0;
>>>>>> +}
>>>>>> +
>>>>>> +static int sca3300_read_reg(struct sca3300_data *sca_data, u8 reg,
>>>>>> int *val)
>>>>>> +{
>>>>>> + int ret;
>>>>>> +
>>>>>> + mutex_lock(&sca_data->lock);
>>>>>> + sca_data->txbuf[0] = SCA3300_X_READ | (reg << 2);
>>>>>> + ret = sca3300_transfer(sca_data, val);
>>>>>> + if (ret > 0) {
>>>>>> + sca_data->txbuf[0] = SCA3300_X_READ | (SCA3300_REG_STATUS
>>>>>> << 2);
>>>>>> + ret = sca3300_transfer(sca_data, val);
>>>>>> + /* status 0 = startup, 0x2 = mode change */
>>>>>> + if (ret > 0 && *val != 0 && *val != 0x2) {
>>>>>> + dev_err_ratelimited(&sca_data->spi->dev,
>>>>>> + "device status: %x\n",
>>>>>> + (u16)*val);
>>>>>> + mutex_unlock(&sca_data->lock);
>>>>>> + return -EIO;
>>>>>> + }
>>>>>> + if (ret > 0)
>>>>>> + ret = 0;
>>>>>> + }
>>>>>> + mutex_unlock(&sca_data->lock);
>>>>>> +
>>>>>> + return ret;
>>>>>> +}
>>>>>> +
>>>>>> +static int sca3300_write_reg(struct sca3300_data *sca_data, u8
>>>>>> reg, int val)
>>>>>> +{
>>>>>> + int reg_val = 0;
>>>>>> + int ret;
>>>>>> +
>>>>>> + mutex_lock(&sca_data->lock);
>>>>>> + sca_data->txbuf[0] = SCA3300_X_WRITE | (reg << 2);
>>>>>> + sca_data->txbuf[1] = val >> 8;
>>>>>> + sca_data->txbuf[2] = val & 0xFF;
>>>>> Prefer (Slightly) an unaligned put.
>>>>>
>>>>>> + ret = sca3300_transfer(sca_data, ®_val);
>>>>>> + if (ret > 0) {
>>>>> Factor this error handling out to another function, plus trigger it
>>>>> from an
>>>>> appropriate standard error code rather than a positive return value.
>>>>>
>>>>>> + sca_data->txbuf[0] = SCA3300_X_READ | (SCA3300_REG_STATUS
>>>>>> << 2);
>>>>>> + ret = sca3300_transfer(sca_data, ®_val);
>>>>>> + /* status 0 = startup, 0x2 = mode change */
>>>>>> + if (ret > 0 && reg_val != 0 && reg_val != 0x2) {
>>>>>> + dev_err_ratelimited(&sca_data->spi->dev,
>>>>>> + "device status: %x\n",
>>>>>> + (u16)reg_val);
>>>>>> + mutex_unlock(&sca_data->lock);
>>>>>> + return -EIO;
>>>>>> + }
>>>>>> + if (ret > 0)
>>>>>> + ret = 0;
>>>>> Whenever you get this sort of juggling it rather implies your design is
>>>>> less than ideal.
>>>>>
>>>>>> + }
>>>>>> + mutex_unlock(&sca_data->lock);
>>>>>> +
>>>>>> + return ret;
>>>>>> +}
>>>>>> +
>>>>>> +static int sca3300_write_raw(struct iio_dev *indio_dev,
>>>>>> + struct iio_chan_spec const *chan,
>>>>>> + int val, int val2, long mask)
>>>>>> +{
>>>>>> + struct sca3300_data *data = iio_priv(indio_dev);
>>>>>> +
>>>>>> + switch (mask) {
>>>>>> + case IIO_CHAN_INFO_SCALE:
>>>>>> + if (val < 0 || val > 3)
>>>>>> + return -EINVAL;
>>>>> No. Scale values need to be the value of 1LSB not a random integer
>>>>> that requires you to look up the datasheet.
>>>>>
>>>>>> + return sca3300_write_reg(data, SCA3300_REG_MODE, val);
>>>>>> + default:
>>>>>> + return -EINVAL;
>>>>>> + }
>>>>>> +}
>>>>>> +
>>>>>> +static int sca3300_read_raw(struct iio_dev *indio_dev,
>>>>>> + struct iio_chan_spec const *chan,
>>>>>> + int *val, int *val2, long mask)
>>>>>> +{
>>>>>> + struct sca3300_data *data = iio_priv(indio_dev);
>>>>>> + int ret;
>>>>>> + int reg_val;
>>>>>> +
>>>>>> + switch (mask) {
>>>>>> + case IIO_CHAN_INFO_RAW:
>>>>>> + ret = sca3300_read_reg(data, chan->address, val);
>>>>>> + if (ret < 0)
>>>>>> + return ret;
>>>>>> + return IIO_VAL_INT;
>>>>>> + case IIO_CHAN_INFO_SCALE:
>>>>>> + ret = sca3300_read_reg(data, SCA3300_REG_MODE, ®_val);
>>>>>> + if (ret < 0)
>>>>>> + return ret;
>>>>>> + *val = sca3300_accel_scale[reg_val];
>>>>> Scale is very very rarely an integer value which makes me wonder what
>>>>> you are returning here... It should be the multiplier needed to
>>>>> take the raw value to a reading in m/sec^2 Given you use it as
>>>>> fractional
>>>>> below, I'm guessing this is 1/scale_value?
>>>>>
>>>>>> + return IIO_VAL_INT;
>>>>>> + case IIO_CHAN_INFO_PROCESSED:
>>>>> Don't provide processed here. Userspace needs to do the conversion
>>>>> itself
>>>>> (and given it has floating point easily available will probably do a
>>>>> better
>>>>> job than we can). I'm assuming the mode can't autonomously change?
>>>>>
>>>>>> + ret = sca3300_read_reg(data, SCA3300_REG_MODE, ®_val);
>>>>>> + if (ret < 0)
>>>>>> + return ret;
>>>>>> + *val2 = sca3300_accel_scale[reg_val];
>>>>>> + ret = sca3300_read_reg(data, chan->address, val);
>>>>>> + if (ret < 0)
>>>>>> + return ret;
>>>>>> + return IIO_VAL_FRACTIONAL;
>>>>>> + default:
>>>>>> + return -EINVAL;
>>>>>> + }
>>>>>> +}
>>>>>> +
>>>>>> +static irqreturn_t sca3300_trigger_handler(int irq, void *p)
>>>>>> +{
>>>>>> + struct iio_poll_func *pf = p;
>>>>>> + struct iio_dev *indio_dev = pf->indio_dev;
>>>>>> + struct sca3300_data *data = iio_priv(indio_dev);
>>>>>> + s64 time_ns = iio_get_time_ns(indio_dev);
>>>>> Is the timestamp at the start more accurate that that at the end
>>>>> of reading the channels? If not, just put this inline in the
>>>>> iio_push_to_buffers_with_timestamp() call.
>>>>>
>>>>>> + int bit, ret, val, i = 0;
>>>>>> +
>>>>>> + for_each_set_bit(bit, indio_dev->active_scan_mask,
>>>>>> + indio_dev->masklength) {
>>>>>> + ret = sca3300_read_reg(data, sca3300_channels[bit].address,
>>>>>> + &val);
>>>>>> + if (ret < 0)
>>>>> Given we can't return an error code from interrupt handlers, it is
>>>>> usually
>>>>> a good idea to print something to the log. Otherwise we get missing
>>>>> data
>>>>> with no idea of why..
>>>>>
>>>>>> + goto out;
>>>>>> + if (ARRAY_SIZE(data->scan.channels) > i)
>>>>> How could this not be true? If it's always true, don't bother
>>>>> checking i.
>>>>>
>>>>>> + ((s16 *)data->scan.channels)[i++] = val;
>>>>>> + }
>>>>>> +
>>>>>> + iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
>>>>>> time_ns);
>>>>>> +out:
>>>>>> + iio_trigger_notify_done(indio_dev->trig);
>>>>>> +
>>>>>> + return IRQ_HANDLED;
>>>>>> +}
>>>>>> +
>>>>>> +static int sca3300_init(struct sca3300_data *sca_data,
>>>>>> + struct iio_dev *indio_dev)
>>>>>> +{
>>>>>> + int ret;
>>>>>> + int value = 0;
>>>>>> +
>>>>>> + if (sca_data->opmode < 1 || sca_data->opmode > 4)
>>>>>> + return -EINVAL;
>>>>> Whilst this is going anyway, better to check that next to where
>>>>> it is read so we drop out immediately rather than buried in this
>>>>> function.
>>>>>
>>>>>> +
>>>>>> + ret = sca3300_write_reg(sca_data, SCA3300_REG_MODE,
>>>>>> + SCA3300_VALUE_SW_RESET);
>>>>>> + if (ret != 0)
>>>>>> + return ret;
>>>>> For sleeps, good to reference which section in data sheet gives the
>>>>> timing.
>>>>>
>>>>>> + usleep_range(2e3, 10e3);
>>>>>> +
>>>>>> + ret = sca3300_write_reg(sca_data, SCA3300_REG_MODE,
>>>>>> + sca_data->opmode - 1);
>>>>>> + if (ret != 0)
>>>>> if (ret) see below.
>>>>>
>>>>>> + return ret;
>>>>>> + msleep(100);
>>>>> Again, document where the time comes from. Saves reviewers time if
>>>>> they want to check it. (I'm too lazy :)
>>>>>
>>>>>> + ret = sca3300_read_reg(sca_data, SCA3300_REG_WHOAMI, &value);
>>>>>> + if (ret != 0)
>>>>> if (ret) is more idiomatic in kernel code.
>>>>>
>>>>>> + return ret;
>>>>>> +
>>>>>> + if (value != SCA3300_DEVICE_ID) {
>>>>>> + dev_err(&sca_data->spi->dev, "device id not expected
>>>>>> value\n");
>>>>> Perhaps useful to print what was expected and what was seen. Maybe it's
>>>>> a new variant and this might help the user to identify that and add
>>>>> it to the
>>>>> driver.
>>>>>
>>>>>> + return -EIO;
>>>>> -EINVAL probably more appropriate return.
>>>>>
>>>>>> + }
>>>>>> + return 0;
>>>>>> +}
>>>>>> +
>>>>>> +static int sca3300_debugfs_reg_access(struct iio_dev *indio_dev,
>>>>>> + unsigned int reg, unsigned int writeval,
>>>>>> + unsigned int *readval)
>>>>>> +{
>>>>>> + struct sca3300_data *data = iio_priv(indio_dev);
>>>>>> + int value;
>>>>>> + int ret;
>>>>>> +
>>>>>> + if (reg > 0x1f)
>>>>> Use a define that names that register.
>>>>>
>>>>>> + return -EINVAL;
>>>>>> +
>>>>>> + if (!readval)
>>>>>> + return sca3300_write_reg(data, reg, writeval);
>>>>>> +
>>>>>> + ret = sca3300_read_reg(data, reg, &value);
>>>>>> + if (ret < 0)
>>>>>> + return ret;
>>>>>> +
>>>>>> + *readval = (unsigned int)value;
>>>>>> +
>>>>>> + return 0;
>>>>>> +}
>>>>>> +
>>>>>> +static const struct iio_info sca3300_info = {
>>>>>> + .read_raw = sca3300_read_raw,
>>>>>> + .write_raw = sca3300_write_raw,
>>>>>> + .debugfs_reg_access = &sca3300_debugfs_reg_access,
>>>>>> +};
>>>>>> +
>>>>>> +static int sca3300_probe(struct spi_device *spi)
>>>>>> +{
>>>>>> + struct sca3300_data *sca_data;
>>>>>> + struct iio_dev *indio_dev;
>>>>>> + int ret;
>>>>>> +
>>>>>> + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*sca_data));
>>>>>> + if (!indio_dev) {
>>>>>> + dev_err(&spi->dev,
>>>>>> + "failed to allocate memory for iio device\n");
>>>>>> + return -ENOMEM;
>>>>>> + }
>>>>>> +
>>>>>> + sca_data = iio_priv(indio_dev);
>>>>>> + mutex_init(&sca_data->lock);
>>>>>> + sca_data->spi = spi;
>>>>>> + spi_set_drvdata(spi, indio_dev);
>>>>> Won't be used once using devm as below and remove() is dropped, so
>>>>> drop this.
>>>>>
>>>>>> +
>>>>>> + crc8_populate_msb(sca3300_crc_table, SCA3300_CRC8_POLYNOMIAL);
>>>>>> +
>>>>>> + indio_dev->dev.parent = &spi->dev;
>>>>>> + indio_dev->info = &sca3300_info;
>>>>>> + indio_dev->name = SCA3300_ALIAS;
>>>>>> + indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED;
>>>>> BUFFER_TRIGGERED bit now set by iio_triggered_buffer_setup() so
>>>>> shouldn't
>>>>> be ehre as well.
>>>>>
>>>>>> + indio_dev->channels = sca3300_channels;
>>>>>> + indio_dev->num_channels = ARRAY_SIZE(sca3300_channels);
>>>>>> + indio_dev->available_scan_masks = sca3300_scan_masks;
>>>>>> +
>>>>>> + if (spi->dev.of_node) {
>>>>>> + ret = of_property_read_u32(spi->dev.of_node, "murata,opmode",
>>>>> Please use generic firmware access calls rather than the of specific
>>>>> ones.
>>>>> That lets us get ACPI support for free :)
>>>>>
>>>>> As per the binding review however, this one needs to go in favour of
>>>>> userspace
>>>>> control of scale + filter frequencies / sampling freq.
>>>>>
>>>>>> + &sca_data->opmode);
>>>>>> + if (ret < 0)
>>>>>> + return ret;
>>>>>> + }
>>>>>> +
>>>>>> + ret = sca3300_init(sca_data, indio_dev);
>>>>>> + if (ret < 0) {
>>>>>> + dev_err(&spi->dev, "failed to init device, error: %d\n",
>>>>>> ret);
>>>>>> + return ret;
>>>>>> + }
>>>>>> +
>>>>>> + ret = iio_triggered_buffer_setup(indio_dev,
>>>>>> iio_pollfunc_store_time,
>>>>>> + sca3300_trigger_handler, NULL);
>>>>> devm_iio_triggered_buffer_setup() and you can drop the manual
>>>>> cleanup in remove()
>>>>> and hence drop remove() entirely as nothing else left.
>>>>>
>>>>>> + if (ret < 0) {
>>>>>> + dev_err(&spi->dev,
>>>>>> + "iio triggered buffer setup failed, error: %d\n", ret);
>>>>>> + return ret;
>>>>>> + }
>>>>>> +
>>>>>> + ret = devm_iio_device_register(&spi->dev, indio_dev);
>>>>>> + if (ret < 0) {
>>>>>> + dev_err(&spi->dev, "iio device register failed, error: %d\n",
>>>>>> + ret);
>>>>>> + iio_triggered_buffer_cleanup(indio_dev);
>>>>> With devm above, no need to manually clean this up.
>>>>>
>>>>>> + return ret;
>>>>>> + }
>>>>>> +
>>>>>> + return 0;
>>>>>> +}
>>>>>> +
>>>>>> +static int sca3300_remove(struct spi_device *spi)
>>>>>> +{
>>>>>> + struct iio_dev *indio_dev = spi_get_drvdata(spi);
>>>>>> +
>>>>>> + iio_triggered_buffer_cleanup(indio_dev);
>>>>>> + return 0;
>>>>>> +}
>>>>>> +
>>>>>> +static const struct of_device_id sca3300_dt_ids[] = {
>>>>>> + { .compatible = "murata,sca3300"},
>>>>>> + {},
>>>>>> +};
>>>>>> +MODULE_DEVICE_TABLE(of, sca3300_dt_ids);
>>>>>> +
>>>>>> +static struct spi_driver sca3300_driver = {
>>>>>> + .driver = {
>>>>>> + .name = SCA3300_ALIAS,
>>>>>> + .owner = THIS_MODULE,
>>>>>> + .of_match_table = of_match_ptr(sca3300_dt_ids),
>>>>>> + },
>>>>>> +
>>>>>> + .probe = sca3300_probe,
>>>>>> + .remove = sca3300_remove,
>>>>>> +};
>>>>>> +
>>>>>> +module_spi_driver(sca3300_driver);
>>>>>> +
>>>>>> +MODULE_AUTHOR("Tomas Melin <tomas.melin@...sala.com>");
>>>>>> +MODULE_DESCRIPTION("Murata SCA3300 SPI Accelerometer");
>>>>>> +MODULE_LICENSE("GPL v2");
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