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

From: Daniel Baluta
Date: Tue Nov 25 2014 - 17:44:26 EST

On Wed, Nov 26, 2014 at 12:31 AM, Hartmut Knaack <knaack.h@xxxxxx> wrote:
> Daniel Baluta schrieb am 25.11.2014 10:54:
>> 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.
>>
> Well, if it makes you happy, then go ahead. My interpretation of a bool is, that an assignment of 0 becomes 0/false, and an assignment of anything else becomes 1/true. So, I wouldn't see a need here (especially since acc_stby/mag_stby were distinctly assigned either 0 or 1).

All right. It makes sense.

>>>> +
>>>> + 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.
>>
> Up to you. Though kmx61_read_raw() would be an example of a function that doesn't follow this convention ;-) And there is no real benefit of checking an error code there, which is passed up anyway.
>>>> + }
>>>> + 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.
>>
> Well, I actually intended to have an unconditional "return ret;" right after the mutex_unlock. But up to you. I also see a good point to make it obvious here, that the return value is IIO_VAL_INT_PLUS_MICRO. So, up to you.
>>>> + 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?
> Since the switch already catches all cases and returns, there is no need for return ret, here. But if you prefer to have a return at the end of the function, you could drop the default case, or leave it empty, or just put a break in there - and return -EINVAL at the end.

Ok. I will remove the the unnecessary return.

>>
>>>> +}
>>>> +
>>>> +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.
> Don't know if Jonathan would like to see it smashed together, already.
> Take care

By together I mean separate patches in the same patch set.

I will take
Daniel.
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