Re: [PATCH v3] iio: imu: Add support for Kionix KMX61 sensor

From: Daniel Baluta
Date: Tue Nov 25 2014 - 04:55:13 EST

On Tue, Nov 25, 2014 at 2:45 AM, Hartmut Knaack <knaack.h@xxxxxx> wrote:
> Daniel Baluta schrieb am 18.11.2014 17:47:
>> Minimal implementation for KMX61 6-axis accelerometer/magnetometer. It exports
>> raw accel/magn readings together with scale and sampling frequency.
>>
>> Datasheet will be available at:
>> http://www.kionix.com/6-axis-accelerometer-magnetometer/kmx61
>>
> Finally managed to have a close look, and found a few issues.
>> Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxxxx>
>> ---
>> Changes since v2:
>> * mostly style fixes after comments received from Jonathan and Peter
>> * http://marc.info/?l=linux-iio&m=141564019602400&w=2
>> * implemented PM runtime and PM sleep resume/suspend hooks
>> * introduced new parameter for kmx61_set_mode to help updating
>> stby bits in kmx61_data.
>> * use kmx6111021 instead of kmx61 for i2c_device_id.
>>
>> drivers/iio/imu/Kconfig | 9 +
>> drivers/iio/imu/Makefile | 2 +
>> drivers/iio/imu/kmx61.c | 766 +++++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 777 insertions(+)
>> create mode 100644 drivers/iio/imu/kmx61.c
>>
>> diff --git a/drivers/iio/imu/Kconfig b/drivers/iio/imu/Kconfig
>> index 2b0e451..d675f43 100644
>> --- a/drivers/iio/imu/Kconfig
>> +++ b/drivers/iio/imu/Kconfig
>> @@ -25,6 +25,15 @@ config ADIS16480
>> Say yes here to build support for Analog Devices ADIS16375, ADIS16480,
>> ADIS16485, ADIS16488 inertial sensors.
>>
>> +config KMX61
>> + tristate "Kionix KMX61 6-axis accelerometer and magnetometer"
>> + depends on I2C
>> + help
>> + Say Y here if you want to build a driver for Kionix KMX61 6-axis accelerometer
>> + and magnetometer.
>> + To compile this driver as module, choose M here: the module will be called
>> + kmx61.
>> +
> This help text is more than 80 characters wide and may better be wrapped a bit differently.

Good catch. checkpatch.pl didn't complain.

>> source "drivers/iio/imu/inv_mpu6050/Kconfig"
>>
>> endmenu
>> diff --git a/drivers/iio/imu/Makefile b/drivers/iio/imu/Makefile
>> index 114d2c1..e1e6e3d 100644
>> --- a/drivers/iio/imu/Makefile
>> +++ b/drivers/iio/imu/Makefile
>> @@ -14,3 +14,5 @@ adis_lib-$(CONFIG_IIO_ADIS_LIB_BUFFER) += adis_buffer.o
>> obj-$(CONFIG_IIO_ADIS_LIB) += adis_lib.o
>>
>> obj-y += inv_mpu6050/
>> +
>> +obj-$(CONFIG_KMX61) += kmx61.o
>> diff --git a/drivers/iio/imu/kmx61.c b/drivers/iio/imu/kmx61.c
>> new file mode 100644
>> index 0000000..f68b3ef
>> --- /dev/null
>> +++ b/drivers/iio/imu/kmx61.c
>> @@ -0,0 +1,766 @@
>> +/*
>> + * KMX61 - Kionix 6-axis Accelerometer/Magnetometer
>> + *
>> + * Copyright (c) 2014, Intel Corporation.
>> + *
>> + * This file is subject to the terms and conditions of version 2 of
>> + * the GNU General Public License. See the file COPYING in the main
>> + * directory of this archive for more details.
>> + *
>> + * IIO driver for KMX61 (7-bit I2C slave address 0x0E or 0x0F).
>> + *
>> + * TODO: buffer, interrupt, thresholds, acpi, temperature sensor
>> + *
>> + */
>> +
>> +#include <linux/module.h>
>> +#include <linux/i2c.h>
>> +#include <linux/pm.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/iio/iio.h>
>> +#include <linux/iio/sysfs.h>
>> +
>> +#define KMX61_DRV_NAME "kmx61"
>> +
>> +#define KMX61_REG_WHO_AM_I 0x00
>> +
>> +/*
>> + * three 16-bit accelerometer output registers for X/Y/Z axis
>> + * we use only XOUT_L as a base register, all other addresses
>> + * can be obtained by applying an offset and are provided here
>> + * only for clarity.
>> + */
>> +#define KMX61_ACC_XOUT_L 0x0A
>> +#define KMX61_ACC_XOUT_H 0x0B
>> +#define KMX61_ACC_YOUT_L 0x0C
>> +#define KMX61_ACC_YOUT_H 0x0D
>> +#define KMX61_ACC_ZOUT_L 0x0E
>> +#define KMX61_ACC_ZOUT_H 0x0F
>> +
>> +/*
>> + * one 16-bit temperature output register
>> + */
>> +#define KMX61_TEMP_L 0x10
>> +#define KMX61_TEMP_H 0x11
>> +
>> +/*
>> + * three 16-bit magnetometer output registers for X/Y/Z axis
>> + */
>> +#define KMX61_MAG_XOUT_L 0x12
>> +#define KMX61_MAG_XOUT_H 0x13
>> +#define KMX61_MAG_YOUT_L 0x14
>> +#define KMX61_MAG_YOUT_H 0x15
>> +#define KMX61_MAG_ZOUT_L 0x16
>> +#define KMX61_MAG_ZOUT_H 0x17
>> +
>> +#define KMX61_REG_ODCNTL 0x2C
>> +#define KMX61_REG_STBY 0x29
>> +#define KMX61_REG_CTRL1 0x2A
>> +
>> +#define KMX61_ACC_STBY_BIT BIT(0)
>> +#define KMX61_MAG_STBY_BIT BIT(1)
>> +#define KMX61_ACT_STBY_BIT BIT(7)
>> +
>> +#define KMX61_ALL_STBY (KMX61_ACC_STBY_BIT | KMX61_MAG_STBY_BIT)
>> +
>> +#define KMX61_REG_CTRL1_GSEL0_SHIFT 0
>> +#define KMX61_REG_CTRL1_GSEL1_SHIFT 1
>> +#define KMX61_REG_CTRL1_GSEL0_MASK 0x01
>> +#define KMX61_REG_CTRL1_GSEL1_MASK 0x02
> I don't see the benefit of separating GSEL0 and GSEL1.
>> +
>> +#define KMX61_REG_CTRL1_BIT_RES BIT(4)
>> +
>> +#define KMX61_ACC_ODR_SHIFT 0
>> +#define KMX61_MAG_ODR_SHIFT 4
>> +#define KMX61_ACC_ODR_MASK 0x0F
>> +#define KMX61_MAG_ODR_MASK 0xF0
>> +
>> +#define KMX61_SLEEP_DELAY_MS 2000
>> +
>> +#define KMX61_CHIP_ID 0x12
>> +
>> +struct kmx61_data {
>> + struct i2c_client *client;
>> +
>> + /* serialize access to non-atomic ops, e.g set_mode */
>> + struct mutex lock;
>> + u8 range;
>> + u8 odr_bits;
>> +
>> + /* standby state */
>> + u8 acc_stby;
>> + u8 mag_stby;
> Why u8 instead of bool?

Hmm, correct. I was thinking bitwise, but you are right. Will fix.

>> +
>> + /* power state */
>> + bool acc_ps;
>> + bool mag_ps;
>> +};
>> +
>> +enum kmx61_range {
>> + KMX61_RANGE_2G,
>> + KMX61_RANGE_4G,
>> + KMX61_RANGE_8G,
>> +};
>> +
>> +enum kmx61_scan {
>> + KMX61_SCAN_ACC_X,
>> + KMX61_SCAN_ACC_Y,
>> + KMX61_SCAN_ACC_Z,
>> + KMX61_SCAN_TEMP,
>> + KMX61_SCAN_MAG_X,
>> + KMX61_SCAN_MAG_Y,
>> + KMX61_SCAN_MAG_Z,
>> +};
>> +
>> +static const struct {
>> + u16 uscale;
>> + u8 gsel0;
>> + u8 gsel1;
>> +} kmx61_scale_table[] = {
>> + {9582, 0, 0},
>> + {19163, 1, 0},
>> + {38326, 0, 1},
> Why not consolidate gsel0 and gsel1 to gsel? Then this could become u16 kmx61_scale[] = {9582, 19163, 38326} with gsel as index.

True. Will fix.

>> +};
>> +
>> +/* KMX61 devices */
>> +#define KMX61_ACC 0x01
>> +#define KMX61_MAG 0x02
>> +
>> +static const struct {
>> + int val;
>> + int val2;
>> + u8 odr_bits;
>> +} kmx61_samp_freq_table[] = { {12, 500000, 0x00},
>> + {25, 0, 0x01},
>> + {50, 0, 0x02},
>> + {100, 0, 0x03},
>> + {200, 0, 0x04},
>> + {400, 0, 0x05},
>> + {800, 0, 0x06},
>> + {1600, 0, 0x07},
>> + {0, 781000, 0x08},
>> + {1, 563000, 0x09},
>> + {3, 125000, 0x0A},
>> + {6, 250000, 0x0B} };
>> +
>> +static IIO_CONST_ATTR(accel_scale_available, "0.009582 0.019163 0.038326");
>> +static IIO_CONST_ATTR(magn_scale_available, "0.001465");
>> +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(
>> + "0.781000 1.563000 3.125000 6.250000 12.500000 25 50 100 200 400 800");
>> +
>> +static struct attribute *kmx61_attributes[] = {
>> + &iio_const_attr_accel_scale_available.dev_attr.attr,
>> + &iio_const_attr_magn_scale_available.dev_attr.attr,
>> + &iio_const_attr_sampling_frequency_available.dev_attr.attr,
>> + NULL,
>> +};
>> +
>> +static const struct attribute_group kmx61_attribute_group = {
>> + .attrs = kmx61_attributes,
>> +};
>> +
>> +#define KMX61_ACC_CHAN(_axis, _index) { \
>> + .type = IIO_ACCEL, \
>> + .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_SAMP_FREQ), \
>> + .address = KMX61_ACC, \
>> + .scan_index = _index, \
>> + .scan_type = { \
>> + .sign = 's', \
>> + .realbits = 12, \
>> + .storagebits = 16, \
>> + .shift = 4, \
>> + .endianness = IIO_LE, \
>> + }, \
>> +}
>> +
>> +#define KMX61_MAG_CHAN(_axis, _index) { \
>> + .type = IIO_MAGN, \
>> + .modified = 1, \
>> + .channel2 = IIO_MOD_ ## _axis, \
>> + .address = KMX61_MAG, \
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
>> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
>> + BIT(IIO_CHAN_INFO_SAMP_FREQ), \
>> + .scan_index = _index, \
>> + .scan_type = { \
>> + .sign = 's', \
>> + .realbits = 14, \
>> + .storagebits = 16, \
>> + .shift = 2, \
>> + .endianness = IIO_LE, \
>> + }, \
>> +}
>> +
>> +static const struct iio_chan_spec kmx61_channels[] = {
>> + KMX61_ACC_CHAN(X, KMX61_SCAN_ACC_X),
>> + KMX61_ACC_CHAN(Y, KMX61_SCAN_ACC_Y),
>> + KMX61_ACC_CHAN(Z, KMX61_SCAN_ACC_Z),
>> + KMX61_MAG_CHAN(X, KMX61_SCAN_MAG_X),
>> + KMX61_MAG_CHAN(Y, KMX61_SCAN_MAG_Y),
>> + KMX61_MAG_CHAN(Z, KMX61_SCAN_MAG_Z),
>> +};
>> +
>> +static int kmx61_convert_freq_to_bit(int val, int val2)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < ARRAY_SIZE(kmx61_samp_freq_table); i++)
>> + if (val == kmx61_samp_freq_table[i].val &&
>> + val2 == kmx61_samp_freq_table[i].val2)
>> + return kmx61_samp_freq_table[i].odr_bits;
>> + return -EINVAL;
>> +}
>> +/**
> Like here, the first line of the following multiline comments have one asterisk too much.

I think this is the convention, when adding doxygen style documentation:
http://lxr.free-electrons.com/source/fs/eventpoll.c#L382

>> + * kmx61_set_mode() - set KMX61 device operating mode
>> + * @data - kmx61 device private data pointer
>> + * @mode - bitmask, indicating operating mode for @device
>> + * @device - bitmask, indicating device for which @mode needs to be set
>> + * @update - update stby bits stored in device's private @data
>> + *
>> + * For each sensor (accelerometer/magnetometer) there are two operating modes
>> + * STANDBY and OPERATION. Neither accel nor magn can be disabled independently
>> + * if they are both enabled. Internal sensors state is saved in acc_stby and
>> + * mag_stby members of driver's private @data.
>> + */
>> +static int kmx61_set_mode(struct kmx61_data *data, u8 mode, u8 device,
>> + bool update)
>> +{
>> + int ret;
>> + int acc_stby = -1, mag_stby = -1;
>> +
>> + ret = i2c_smbus_read_byte_data(data->client, KMX61_REG_STBY);
>> + if (ret < 0) {
>> + dev_err(&data->client->dev, "Error reading reg_stby\n");
>> + return ret;
>> + }
>> + if (device & KMX61_ACC) {
>> + if (mode & KMX61_ACC_STBY_BIT) {
>> + ret |= KMX61_ACC_STBY_BIT;
>> + acc_stby = 1;
>> + } else {
>> + ret &= ~KMX61_ACC_STBY_BIT;
>> + acc_stby = 0;
>> + }
>> + }
>> +
>> + if (device & KMX61_MAG) {
>> + if (mode & KMX61_MAG_STBY_BIT) {
>> + ret |= KMX61_MAG_STBY_BIT;
>> + mag_stby = 1;
>> + } else {
>> + ret &= ~KMX61_MAG_STBY_BIT;
>> + mag_stby = 0;
>> + }
>> + }
>> +
>> + ret = i2c_smbus_write_byte_data(data->client, KMX61_REG_STBY, ret);
>> + if (ret < 0) {
>> + dev_err(&data->client->dev, "Error writing reg_stby\n");
>> + return ret;
>> + }
>> +
>> + if (acc_stby != -1 && update)
>> + data->acc_stby = !!acc_stby;
>> + if (mag_stby != -1 && update)
>> + data->mag_stby = !!mag_stby;
> Why is there a need for double negation?

Correct. Now it doesn't make sense since data->acc_stby is u8.

But, with your suggestion if I will use bool to represent data->acc_stby
then I think the code should use double negation to make it clear
that data->acc_stby is bool and acc_stby is int.

>> +
>> + return ret;
> Since no error occured until this point, just return 0.

Ok. Will fix.

>> +}
>> +
>> +static int kmx61_get_mode(struct kmx61_data *data, u8 *mode, u8 device)
>> +{
>> + int ret;
>> +
>> + ret = i2c_smbus_read_byte_data(data->client, KMX61_REG_STBY);
>> + if (ret < 0) {
>> + dev_err(&data->client->dev, "Error reading reg_stby\n");
>> + return ret;
>> + }
>> + *mode = 0;
>> +
>> + if (device & KMX61_ACC) {
>> + if (ret & KMX61_ACC_STBY_BIT)
>> + *mode |= KMX61_ACC_STBY_BIT;
>> + else
>> + *mode &= ~KMX61_ACC_STBY_BIT;
> Simply:
> *mode |= ret & KMX61_ACC_STBY_BIT;
Ok.

>> + }
>> +
>> + if (device & KMX61_MAG) {
>> + if (ret & KMX61_MAG_STBY_BIT)
>> + *mode |= KMX61_MAG_STBY_BIT;
>> + else
>> + *mode &= ~KMX61_MAG_STBY_BIT;
> Same here:
Ok.

> *mode |= ret & KMX61_MAG_STBY_BIT;
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int kmx61_set_odr(struct kmx61_data *data, int val, int val2, u8 device)
>> +{
>> + int ret;
>> + u8 mode;
>> + int lodr_bits, odr_bits;
>> +
>> + ret = kmx61_get_mode(data, &mode, KMX61_ACC | KMX61_MAG);
>> + if (ret < 0)
>> + return ret;
>> +
>> + lodr_bits = kmx61_convert_freq_to_bit(val, val2);
>> + if (lodr_bits < 0)
>> + return lodr_bits;
>> +
>> + /* To change ODR, accel and magn must be in STDBY */
>> + ret = kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG,
>> + true);
>> + if (ret < 0)
>> + return ret;
>> +
>> + odr_bits = 0;
>> + if (device & KMX61_ACC)
>> + odr_bits |= lodr_bits;
>> + if (device & KMX61_MAG)
>> + odr_bits |= (lodr_bits << KMX61_MAG_ODR_SHIFT);
> No need for parenthesis.
ok.

>> +
>> + ret = i2c_smbus_write_byte_data(data->client, KMX61_REG_ODCNTL,
>> + odr_bits);
>> + if (ret < 0)
>> + return ret;
>> +
>> + ret = kmx61_set_mode(data, mode, KMX61_ACC | KMX61_MAG, true);
>> + if (ret < 0)
>> + return ret;
>> +
>> + data->odr_bits = lodr_bits;
>> +
>> + return 0;
>> +}
>> +
>> +static
>> +int kmx61_get_odr(struct kmx61_data *data, int *val, int *val2, u8 device)
> Usually wrap parameters? And don't put code on line with {.

Will fix.

>> +{ int i;
>> + u8 lodr_bits;
>> +
>> + if (device & KMX61_ACC)
>> + lodr_bits = (data->odr_bits >> KMX61_ACC_ODR_SHIFT) &
>> + KMX61_ACC_ODR_MASK;
> KMX61_ACC_ODR_SHIFT is just a placebo and not used in kmx61_set_odr. Choose one way and stay consistent.

placebo is good. will fix kmx61_set_odr :)

>> + else if (device & KMX61_MAG)
>> + lodr_bits = (data->odr_bits >> KMX61_MAG_ODR_SHIFT) &
>> + KMX61_MAG_ODR_MASK;
>> + else
>> + return -EINVAL;
>> +
>> + for (i = 0; i < ARRAY_SIZE(kmx61_samp_freq_table); i++)
>> + if (lodr_bits == kmx61_samp_freq_table[i].odr_bits) {
>> + *val = kmx61_samp_freq_table[i].val;
>> + *val2 = kmx61_samp_freq_table[i].val2;
>> + return 0;
> return IIO_VAL_INT_PLUS_MICRO allows you to faciliate _read_raw a bit to just return ret there.

Hmm, If you don't mind I want to keep this as it is, just to
be consistent with the rest of the functions. The convention
used is to return 0 in case of success.

>> + }
>> + return -EINVAL;
>> +}
>> +
>> +static int kmx61_set_range(struct kmx61_data *data, int range)
>> +{
>> + int ret;
>> +
>> + ret = i2c_smbus_read_byte_data(data->client, KMX61_REG_CTRL1);
>> + if (ret < 0) {
>> + dev_err(&data->client->dev, "Error reading reg_ctrl1\n");
>> + return ret;
>> + }
>> +
>> + ret &= ~(KMX61_REG_CTRL1_GSEL0_MASK | KMX61_REG_CTRL1_GSEL1_MASK);
>> + ret |= kmx61_scale_table[range].gsel0 << KMX61_REG_CTRL1_GSEL0_SHIFT;
>> + ret |= kmx61_scale_table[range].gsel1 << KMX61_REG_CTRL1_GSEL1_SHIFT;
>> +
>> + ret = i2c_smbus_write_byte_data(data->client, KMX61_REG_CTRL1, ret);
>> + if (ret < 0) {
>> + dev_err(&data->client->dev, "Error writing reg_ctrl1\n");
>> + return ret;
>> + }
>> +
>> + data->range = range;
>> +
>> + return 0;
>> +}
>> +
>> +static int kmx61_set_scale(struct kmx61_data *data, int uscale)
>> +{
>> + int ret, i;
>> + u8 mode;
>> +
>> + for (i = 0; i < ARRAY_SIZE(kmx61_scale_table); i++) {
>> + if (kmx61_scale_table[i].uscale == uscale) {
>> + ret = kmx61_get_mode(data, &mode,
>> + KMX61_ACC | KMX61_MAG);
>> + if (ret < 0)
>> + return ret;
>> +
>> + ret = kmx61_set_mode(data, KMX61_ALL_STBY,
>> + KMX61_ACC | KMX61_MAG, true);
>> + if (ret < 0)
>> + return ret;
>> +
>> + ret = kmx61_set_range(data, i);
>> + if (ret < 0)
>> + return ret;
>> +
>> + return kmx61_set_mode(data, mode,
>> + KMX61_ACC | KMX61_MAG, true);
>> + }
>> + }
>> + return -EINVAL;
>> +}
>> +
>> +static int kmx61_chip_init(struct kmx61_data *data)
>> +{
>> + int ret;
>> +
>> + ret = i2c_smbus_read_byte_data(data->client, KMX61_REG_WHO_AM_I);
>> + if (ret < 0) {
>> + dev_err(&data->client->dev, "Error reading who_am_i\n");
>> + return ret;
>> + }
>> +
>> + if (ret != KMX61_CHIP_ID) {
>> + dev_err(&data->client->dev,
>> + "Wrong chip id, got %x expected %x\n",
>> + ret, KMX61_CHIP_ID);
>> + return -EINVAL;
>> + }
>> +
>> + /* set accel 12bit, 4g range */
>> + ret = kmx61_set_range(data, KMX61_RANGE_4G);
>> + if (ret < 0)
>> + return ret;
>> +
>> + /* set acc/magn to OPERATION mode */
>> + ret = kmx61_set_mode(data, 0, KMX61_ACC | KMX61_MAG, true);
> Just return kmx61_set_mode(data, 0, KMX61_ACC | KMX61_MAG, true);

Ok.

>> + if (ret < 0)
>> + return ret;
>> +
>> + return 0;
>> +}
>> +/**
>> + * kmx61_set_power_state() - set power state for kmx61 @device
>> + * @data - kmx61 device private pointer
>> + * @on - power state to be set for @device
>> + * @device - bitmask indicating device for which @on state needs to be set
>> + *
>> + * Notice that when ACC power state needs to be set to ON and MAG is in
>> + * OPERATION then we know that kmx61_runtime_resume was already called
>> + * so we must set ACC OPERATION mode here. The same happens when MAG power
>> + * state needs to be set to ON and ACC is in OPERATION.
>> + */
>> +static int kmx61_set_power_state(struct kmx61_data *data, bool on, u8 device)
>> +{
>> +#ifdef CONFIG_PM_RUNTIME
>> + int ret;
>> +
>> + if (device & KMX61_ACC) {
>> + if (on && !data->acc_ps && !data->mag_stby)
>> + kmx61_set_mode(data, 0, KMX61_ACC, true);
>> + data->acc_ps = on;
>> + }
>> + if (device & KMX61_MAG) {
>> + if (on && !data->mag_ps && !data->acc_stby)
>> + kmx61_set_mode(data, 0, KMX61_MAG, true);
>> + data->mag_ps = on;
>> + }
>> +
>> + if (on) {
>> + ret = pm_runtime_get_sync(&data->client->dev);
>> + } else {
>> + pm_runtime_mark_last_busy(&data->client->dev);
>> + ret = pm_runtime_put_autosuspend(&data->client->dev);
>> + }
>> + if (ret < 0) {
>> + dev_err(&data->client->dev,
>> + "Failed: kmx61_set_power_state for %d, ret %d\n",
>> + on, ret);
>> + return ret;
>> + }
>> +#endif
>> + return 0;
>> +}
>> +
>> +static int kmx61_read_measurement(struct kmx61_data *data, int base, int offset)
> u8 base, u8 offset?

Correct.

>> +{
>> + int ret;
>> + u8 reg = base + offset * 2;
>> +
>> + ret = i2c_smbus_read_word_data(data->client, reg);
>> + if (ret < 0) {
>> + dev_err(&data->client->dev, "failed to read reg at %x\n", reg);
>> + return ret;
> This return is unnecessary.

Ok.

>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static int kmx61_read_raw(struct iio_dev *indio_dev,
>> + struct iio_chan_spec const *chan, int *val,
>> + int *val2, long mask)
> Indentation of the parameters is a bit too high.

Ok, will fix.

>> +{
>> + struct kmx61_data *data = iio_priv(indio_dev);
>> + int ret;
>> + u8 base_reg;
>> +
>> + switch (mask) {
>> + case IIO_CHAN_INFO_RAW:
>> + switch (chan->type) {
>> + case IIO_ACCEL:
>> + case IIO_MAGN:
>> + base_reg = KMX61_ACC_XOUT_L;
>> + break;
>> + default:
>> + return -EINVAL;
>> + }
>> + mutex_lock(&data->lock);
>> +
>> + kmx61_set_power_state(data, true, chan->address);
>> + ret = kmx61_read_measurement(data, base_reg, chan->scan_index);
>> + if (ret < 0) {
>> + kmx61_set_power_state(data, false, chan->address);
>> + mutex_unlock(&data->lock);
>> + return ret;
>> + }
>> + *val = sign_extend32(ret >> chan->scan_type.shift,
>> + chan->scan_type.realbits - 1);
>> + kmx61_set_power_state(data, false, chan->address);
>> +
>> + mutex_unlock(&data->lock);
>> + return IIO_VAL_INT;
>> + case IIO_CHAN_INFO_SCALE:
>> + switch (chan->type) {
>> + case IIO_ACCEL:
>> + *val = 0;
>> + *val2 = kmx61_scale_table[data->range].uscale;
>> + return IIO_VAL_INT_PLUS_MICRO;
>> + case IIO_MAGN:
>> + /* 14 bits res, 1465 microGauss per magn count */
>> + *val = 0;
>> + *val2 = 1465;
>> + return IIO_VAL_INT_PLUS_MICRO;
>> + default:
>> + return -EINVAL;
>> + }
>> + case IIO_CHAN_INFO_SAMP_FREQ:
>> + if (chan->type != IIO_ACCEL && chan->type != IIO_MAGN)
>> + return -EINVAL;
>> +
>> + mutex_lock(&data->lock);
>> + ret = kmx61_get_odr(data, val, val2, chan->address);
>> + mutex_unlock(&data->lock);
> Could be just return ret here, if kmx61_get_odr() returns IIO_VAL_INT_PLUS_MICRO on success and -EINVAL on error.

As explained above, I prefer not to do this. More than that, I can't do ret here
because the data->lock is held.

>> + if (ret)
>> + return -EINVAL;
>> + return IIO_VAL_INT_PLUS_MICRO;
>> + }
>> + return -EINVAL;
>> +}
>> +
>> +static int kmx61_write_raw(struct iio_dev *indio_dev,
>> + struct iio_chan_spec const *chan, int val,
>> + int val2, long mask)
> Indentation of parameters is too high.
Ok.
>> +{
>> + struct kmx61_data *data = iio_priv(indio_dev);
>> + int ret;
>> +
>> + switch (mask) {
>> + case IIO_CHAN_INFO_SAMP_FREQ:
>> + if (chan->type != IIO_ACCEL && chan->type != IIO_MAGN)
>> + return -EINVAL;
>> +
>> + mutex_lock(&data->lock);
>> + ret = kmx61_set_odr(data, val, val2, chan->address);
>> + mutex_unlock(&data->lock);
>> + return ret;
>> + case IIO_CHAN_INFO_SCALE:
>> + switch (chan->type) {
>> + case IIO_ACCEL:
>> + if (val != 0)
>> + return -EINVAL;
>> + mutex_lock(&data->lock);
>> + ret = kmx61_set_scale(data, val2);
>> + mutex_unlock(&data->lock);
>> + return ret;
>> + default:
>> + return -EINVAL;
>> + }
>> + return ret;
> This won't be reached (if so, ret would not be initialized).
>> + default:
>> + return -EINVAL;
>> + }
>> + return ret;
> Same here.

I know. Would initializing ret with 0 will be enough?

>> +}
>> +
>> +static const struct iio_info kmx61_info = {
>> + .driver_module = THIS_MODULE,
>> + .read_raw = kmx61_read_raw,
>> + .write_raw = kmx61_write_raw,
>> + .attrs = &kmx61_attribute_group,
>> +};
>> +
>> +static int kmx61_probe(struct i2c_client *client,
>> + const struct i2c_device_id *id)
>> +{
>> + struct kmx61_data *data;
>> + struct iio_dev *indio_dev;
>> + int ret;
>> + const char *name = NULL;
>> +
>> + indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
>> + if (!indio_dev)
>> + return -ENOMEM;
>> +
>> + data = iio_priv(indio_dev);
>> + i2c_set_clientdata(client, indio_dev);
>> + data->client = client;
>> +
>> + if (id)
>> + name = id->name;
>> +
>> + indio_dev->dev.parent = &client->dev;
>> + indio_dev->channels = kmx61_channels;
>> + indio_dev->num_channels = ARRAY_SIZE(kmx61_channels);
>> + indio_dev->name = name;
>> + indio_dev->modes = INDIO_DIRECT_MODE;
>> + indio_dev->info = &kmx61_info;
>> +
>> + mutex_init(&data->lock);
>> +
>> + ret = kmx61_chip_init(data);
>> + if (ret < 0)
>> + return ret;
>> +
>> + ret = iio_device_register(indio_dev);
>> + if (ret < 0) {
>> + dev_err(&client->dev, "Failed to register iio device\n");
>> + goto err_iio_device_register;
>> + }
>> +
>> + ret = pm_runtime_set_active(&client->dev);
>> + if (ret < 0)
>> + goto err_pm_runtime_set_active;
>> +
>> + pm_runtime_enable(&client->dev);
>> + pm_runtime_set_autosuspend_delay(&client->dev, KMX61_SLEEP_DELAY_MS);
>> + pm_runtime_use_autosuspend(&client->dev);
>> +
>> + return 0;
>> +
>> +err_pm_runtime_set_active:
>> + iio_device_unregister(indio_dev);
>> +err_iio_device_register:
>> + kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG, true);
>> + return ret;
>> +}
>> +
>> +static int kmx61_remove(struct i2c_client *client)
>> +{
>> + struct iio_dev *indio_dev = i2c_get_clientdata(client);
>> + struct kmx61_data *data = iio_priv(indio_dev);
>> + int ret;
>> +
>> + pm_runtime_disable(&client->dev);
>> + pm_runtime_set_suspended(&client->dev);
>> + pm_runtime_put_noidle(&client->dev);
>> +
>> + iio_device_unregister(indio_dev);
>> +
>> + mutex_lock(&data->lock);
>> + ret = kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG, true);
>> + mutex_unlock(&data->lock);
>> +
>> + return ret;
>> +}
>> +
>> +#ifdef CONFIG_PM_SLEEP
>> +static int kmx61_suspend(struct device *dev)
>> +{
>> + struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
>> + struct kmx61_data *data = iio_priv(indio_dev);
>> + int ret;
>> +
>> + mutex_lock(&data->lock);
>> + ret = kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG,
>> + false);
>> + mutex_unlock(&data->lock);
>> +
>> + return ret;
>> +}
>> +
>> +static int kmx61_resume(struct device *dev)
>> +{
>> + struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
>> + struct kmx61_data *data = iio_priv(indio_dev);
>> + u8 stby = 0;
>> +
>> + if (data->acc_stby)
>> + stby |= KMX61_ACC_STBY_BIT;
>> + if (data->mag_stby)
>> + stby |= KMX61_MAG_STBY_BIT;
>> +
>> + return kmx61_set_mode(data, stby, KMX61_ACC | KMX61_MAG, true);
>> +}
>> +#endif
>> +
>> +#ifdef CONFIG_PM_RUNTIME
>> +static int kmx61_runtime_suspend(struct device *dev)
>> +{
>> + struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
>> + struct kmx61_data *data = iio_priv(indio_dev);
>> + int ret;
>> +
>> + mutex_lock(&data->lock);
>> + ret = kmx61_set_mode(data, KMX61_ALL_STBY, KMX61_ACC | KMX61_MAG, true);
>> + mutex_unlock(&data->lock);
>> +
>> + return ret;
>> +}
>> +
>> +static int kmx61_runtime_resume(struct device *dev)
>> +{
>> + struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
>> + struct kmx61_data *data = iio_priv(indio_dev);
>> + u8 stby = 0;
>> +
>> + if (!data->acc_ps)
>> + stby |= KMX61_ACC_STBY_BIT;
>> + if (!data->mag_ps)
>> + stby |= KMX61_MAG_STBY_BIT;
>> +
>> + return kmx61_set_mode(data, stby, KMX61_ACC | KMX61_MAG, true);
>> +}
>> +#endif
>> +
>> +static const struct dev_pm_ops kmx61_pm_ops = {
>> + SET_SYSTEM_SLEEP_PM_OPS(kmx61_suspend, kmx61_resume)
>> + SET_RUNTIME_PM_OPS(kmx61_runtime_suspend, kmx61_runtime_resume, NULL)
>> +};
>> +
>> +static const struct i2c_device_id kmx61_id[] = {
>> + {"kmx611021", 0},
>> + {}
>> +};
>> +
>> +MODULE_DEVICE_TABLE(i2c, kmx61_id);
>> +
>> +static struct i2c_driver kmx61_driver = {
>> + .driver = {
>> + .name = KMX61_DRV_NAME,
>> + .pm = &kmx61_pm_ops,
>> + },
>> + .probe = kmx61_probe,
>> + .remove = kmx61_remove,
>> + .id_table = kmx61_id,
>> +};
>> +
>> +module_i2c_driver(kmx61_driver);
>> +
>> +MODULE_AUTHOR("Daniel Baluta <daniel.baluta@xxxxxxxxx>");
>> +MODULE_DESCRIPTION("KMX61 accelerometer/magnetometer driver");
>> +MODULE_LICENSE("GPL v2");

Hartmut, thanks a lot for your reviews. I will send a patch series
with these cleanups together with changes for ACPI, buffer and trigger
support.

Daniel.
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