Re: [RFC v2 1/1] iio: light: add MAX30100 oximeter driver support

[Jonathan Cameron <jic23@kernel.org>]

On 22/11/15 12:07, Matt Ranostay wrote:
> On Sat, Nov 21, 2015 at 11:26 PM, Jonathan Cameron <jic23@kernel.org> wrote:
>> On 20/11/15 16:40, Peter Meerwald-Stadler wrote:
>>> On Wed, 18 Nov 2015, Matt Ranostay wrote:
>>>
>>>> MAX30100 is an heart rate and pulse oximeter sensor that works using
>>>> two LEDS of different wavelengths, and detecting the light reflected
>>>> back.
>>>>
>>>> This patchset adds support for both IR and RED LED channels which can
>>>
>>> red? this refers to a LED with visible red color?
>>> more nitpicking below
>> As I'm here, I'll answer that one.  Yes.  Absolutely, it's 700->800nm light
>> which pretty much makes it mostly visible red.
> 
> Yeah this device uses a "red" light (aka close enough to wavelength)
> mainly for the oxygen reading.
Basically all this email says is yes to documenting the not using interrupt for
temp reading bit.

J
> 
>>>
>>>> be processed in userspace to determine heart rate and blood oxygen
>>>> levels.
>>>>
>>>> Signed-off-by: Matt Ranostay <mranostay@gmail.com>
>> Few additional comments from me.  Coming along nicely.
>>
>> Guessing we want to hold this until you have real hardware tested with
>> the final version anyway.  Should be plenty of time.
>>
>> Jonathan
>>>> ---
>>>>  .../devicetree/bindings/iio/light/max30100.txt     |  22 ++
>>>>  drivers/iio/Kconfig                                |   1 +
>>>>  drivers/iio/Makefile                               |   1 +
>>>>  drivers/iio/health/Kconfig                         |  21 +
>>>>  drivers/iio/health/Makefile                        |   7 +
>>>>  drivers/iio/health/max30100.c                      | 423 +++++++++++++++++++++
>>>>  6 files changed, 475 insertions(+)
>>>>  create mode 100644 Documentation/devicetree/bindings/iio/light/max30100.txt
>>>>  create mode 100644 drivers/iio/health/Kconfig
>>>>  create mode 100644 drivers/iio/health/Makefile
>>>>  create mode 100644 drivers/iio/health/max30100.c
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/iio/light/max30100.txt b/Documentation/devicetree/bindings/iio/light/max30100.txt
>>>> new file mode 100644
>>>> index 0000000..435d6fc
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/iio/light/max30100.txt
>>>> @@ -0,0 +1,22 @@
>>>> +* Maxim MAX30100 heart rate and pulse oximeter sensor
>>>> +
>>>> +https://datasheets.maximintegrated.com/en/ds/MAX30100.pdf
>>>> +
>>>> +Required properties:
>>>> +
>>>> +  - compatible: must be "maxim,max30100"
>>>> +  - reg: the I2c address of the sensor
>>>
>>> I2C
>>>
>>>> +  - interrupt-parent: should be the phandle for the interrupt controller
>>>> +  - interrupts : the sole interrupt generated by the device
>>>
>>> no space before : for consistency
>>>
>>>> +
>>>> +  Refer to interrupt-controller/interrupts.txt for generic interrupt client
>>>> +  node bindings.
>>>> +
>>>> +Example:
>>>> +
>>>> +max30100@57 {
>>>> +    compatible = "maxim,max30100";
>>>> +    reg = <0x57>;
>>>> +    interrupt-parent = <&gpio1>;
>>>> +    interrupts = <16 2>;
>>>> +};
>>>> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
>>>> index 5dfb4f1..b846873 100644
>>>> --- a/drivers/iio/Kconfig
>>>> +++ b/drivers/iio/Kconfig
>>>> @@ -68,6 +68,7 @@ source "drivers/iio/common/Kconfig"
>>>>  source "drivers/iio/dac/Kconfig"
>>>>  source "drivers/iio/frequency/Kconfig"
>>>>  source "drivers/iio/gyro/Kconfig"
>>>> +source "drivers/iio/health/Kconfig"
>>>>  source "drivers/iio/humidity/Kconfig"
>>>>  source "drivers/iio/imu/Kconfig"
>>>>  source "drivers/iio/light/Kconfig"
>>>> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
>>>> index dc73c1f..7371791 100644
>>>> --- a/drivers/iio/Makefile
>>>> +++ b/drivers/iio/Makefile
>>>> @@ -20,6 +20,7 @@ obj-y += common/
>>>>  obj-y += dac/
>>>>  obj-y += gyro/
>>>>  obj-y += frequency/
>>>> +obj-y += health/
>>>>  obj-y += humidity/
>>>>  obj-y += imu/
>>>>  obj-y += light/
>>>> diff --git a/drivers/iio/health/Kconfig b/drivers/iio/health/Kconfig
>>>> new file mode 100644
>>>> index 0000000..30d4ca0
>>>> --- /dev/null
>>>> +++ b/drivers/iio/health/Kconfig
>>>> @@ -0,0 +1,21 @@
>>>> +#
>>>> +# Health sensors
>>>> +#
>>>> +# When adding new entries keep the list in alphabetical order
>>>> +
>>>> +menu "Health sensors"
>>>> +
>>>> +config MAX30100
>>>> +    tristate "MAX30100 heart rate and pulse oximeter sensor"
>>>> +    depends on I2C
>>>> +    select REGMAP_I2C
>>>> +    select IIO_BUFFER
>>>> +    select IIO_KFIFO_BUF
>>>> +    help
>>>> +      Say Y here to build I2C interface support for the Maxim
>>>> +      MAX30100 heart rate, and pulse oximeter sensor.
>>>> +
>>>> +      To compile this driver as a module, choose M here: the
>>>> +      module will be called max30100
>>>
>>> put a full stop (.) at the end of the sentence maybe :)
>>>
>>>> +
>>>> +endmenu
>>>> diff --git a/drivers/iio/health/Makefile b/drivers/iio/health/Makefile
>>>> new file mode 100644
>>>> index 0000000..7c475d7
>>>> --- /dev/null
>>>> +++ b/drivers/iio/health/Makefile
>>>> @@ -0,0 +1,7 @@
>>>> +#
>>>> +# Makefile for IIO Health sensors
>>>> +#
>>>> +
>>>> +# When adding new entries keep the list in alphabetical order
>>>> +
>>>> +obj-$(CONFIG_MAX30100)              += max30100.o
>>>> diff --git a/drivers/iio/health/max30100.c b/drivers/iio/health/max30100.c
>>>> new file mode 100644
>>>> index 0000000..3ad6b31
>>>> --- /dev/null
>>>> +++ b/drivers/iio/health/max30100.c
>>>> @@ -0,0 +1,423 @@
>>>> +/*
>>>> + * max30100.c - Support for MAX30100 heart rate and pulse oximeter sensor
>>>> + *
>>>> + * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com>
>>>> + *
>>>> + * This program is free software; you can redistribute it and/or modify
>>>> + * it under the terms of the GNU General Public License as published by
>>>> + * the Free Software Foundation; either version 2 of the License, or
>>>> + * (at your option) any later version.
>>>> + *
>>>> + * This program is distributed in the hope that it will be useful,
>>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>>>> + * GNU General Public License for more details.
>>>> + *
>>>> + */
>>>> +
>>>> +#include <linux/module.h>
>>>> +#include <linux/init.h>
>>>> +#include <linux/interrupt.h>
>>>> +#include <linux/delay.h>
>>>> +#include <linux/err.h>
>>>> +#include <linux/irq.h>
>>>> +#include <linux/i2c.h>
>>>> +#include <linux/mutex.h>
>>>> +#include <linux/regmap.h>
>>>> +#include <linux/iio/iio.h>
>>>> +#include <linux/iio/buffer.h>
>>>> +#include <linux/iio/kfifo_buf.h>
>>>> +
>>>> +#define MAX30100_REGMAP_NAME        "max30100_regmap"
>>>> +#define MAX30100_DRV_NAME   "max30100"
>>>> +
>>>> +#define MAX30100_REG_INT_STATUS                     0x00
>>>> +#define MAX30100_REG_INT_STATUS_PWR_RDY             BIT(0)
>>>> +#define MAX30100_REG_INT_STATUS_SPO2_RDY    BIT(4)
>>>> +#define MAX30100_REG_INT_STATUS_HR_RDY              BIT(5)
>>>> +
>>>> +#define MAX30100_REG_INT_ENABLE                     0x01
>>>> +#define MAX30100_REG_INT_ENABLE_HR_EN               BIT(0)
>>>> +#define MAX30100_REG_INT_ENABLE_SPO2_EN             BIT(1)
>>>> +#define MAX30100_REG_INT_ENABLE_MASK                0xf0
>>>> +#define MAX30100_REG_INT_ENABLE_MASK_SHIFT  4
>>>> +
>>>> +#define MAX30100_REG_FIFO_DATA                      0x05
>>>> +
>>>> +#define MAX30100_REG_MODE_CONFIG            0x06
>>>> +#define MAX30100_REG_MODE_CONFIG_MODE_HR_EN BIT(0)
>>>> +#define MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN       BIT(1)
>>>> +#define MAX30100_REG_MODE_CONFIG_MODE_MASK  0x03
>>>> +#define MAX30100_REG_MODE_CONFIG_TEMP_EN    BIT(3)
>>>> +#define MAX30100_REG_MODE_CONFIG_PWR                BIT(7)
>>>> +
>>>> +#define MAX30100_REG_SPO2_CONFIG            0x07
>>>> +#define MAX30100_REG_SPO2_CONFIG_HI_RES_EN  BIT(6)
>>>> +
>>>> +#define MAX30100_REG_SPO2_CONFIG_100HZ              BIT(2)
>>>> +#define MAX30100_REG_SPO2_CONFIG_1600US             0x3
>>>> +
>>>> +#define MAX30100_REG_LED_CONFIG                     0x09
>>>> +#define MAX30100_REG_LED_CONFIG_RED_LED_SHIFT       4
>>>> +
>>>> +#define MAX30100_REG_LED_CONFIG_24MA                0x07
>>>> +#define MAX30100_REG_LED_CONFIG_50MA                0x0f
>>>> +
>>>> +#define MAX30100_REG_TEMP_INTEGER           0x16
>>>> +#define MAX30100_REG_TEMP_FRACTION          0x17
>>>> +
>>>> +struct max30100_data {
>>>> +    struct iio_dev *indio_dev;
>> This is only used in one place and there is a perfectly good pointer to
>> this in the interrupt anyway so drop it from here.  (note this is a
>> common one to spot, there is very rarely a good reason to have a pointer
>> to the struct iio_dev in the private data.  Everything should be the other
>> way around!)
> 
> Ah right :)
>>
>>
>>>> +    struct mutex lock;
>>>> +    struct regmap *regmap;
>>>> +
>>>> +    u8 buffer[4]; /* 4 8-bit channels */
>>>> +};
>>>> +
>>>> +static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg)
>>>> +{
>>>> +    switch (reg) {
>>>> +    case MAX30100_REG_INT_STATUS:
>>>> +    case MAX30100_REG_MODE_CONFIG:
>>>> +    case MAX30100_REG_FIFO_DATA:
>>>> +    case MAX30100_REG_TEMP_INTEGER:
>>>> +    case MAX30100_REG_TEMP_FRACTION:
>>>> +            return true;
>>>> +    default:
>>>> +            return false;
>>>> +    }
>>>> +}
>>>> +
>>>> +static const struct regmap_config max30100_regmap_config = {
>>>> +    .name = MAX30100_REGMAP_NAME,
>>>> +
>>>> +    .reg_bits = 8,
>>>> +    .val_bits = 8,
>>>> +
>>>> +    .max_register = MAX30100_REG_LED_CONFIG,
>>>> +    .cache_type = REGCACHE_FLAT,
>>>> +
>>>> +    .volatile_reg = max30100_is_volatile_reg,
>>>> +};
>>>> +
>>>> +static const unsigned long max30100_scan_masks[] = {0x3, 0};
>>>> +
>>>> +static const struct iio_chan_spec max30100_channels[] = {
>>>> +    {
>>>> +            .type = IIO_INTENSITY,
>>>> +            .channel2 = IIO_MOD_LIGHT_IR,
>>>> +
>>>> +            .scan_index = 0,
>>>> +            .scan_type = {
>>>> +                    .sign = 'u',
>>>> +                    .realbits = 16,
>>>> +                    .storagebits = 16,
>>>> +                    .endianness = IIO_BE,
>>>> +            },
>>>> +    },
>>>> +    {
>>>> +            .type = IIO_INTENSITY,
>>>> +            .channel2 = IIO_MOD_LIGHT_RED,
>>>> +
>>>> +            .scan_index = 1,
>>>> +            .scan_type = {
>>>> +                    .sign = 'u',
>>>> +                    .realbits = 16,
>>>
>>> max30100_interrupt_handler() reads 4 bytes?!
>>>
>>> description of buffer in max30100_data:
>>> u8 buffer[4]; /* 4 8-bit channels */
>>> this is confusing; maybe __be16 buffer[2]?
>> Agreed, __be16 version preferred.  Makes it explicit
>> what we have and fix the description (good spot Peter!)
>>>
>>>> +                    .storagebits = 16,
>>>> +                    .endianness = IIO_BE,
>>>> +            },
>>>> +    },
>>>> +    {
>>>> +            .type = IIO_TEMP,
>>>> +            .info_mask_separate =
>>>> +                    BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
>>>> +            .scan_index = -1,
>>>> +    },
>>>> +};
>>>> +
>>>> +static int max30100_set_powermode(struct max30100_data *data, bool state)
>>>> +{
>>>> +    return regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
>>>> +                              MAX30100_REG_MODE_CONFIG_PWR,
>>>> +                              state ? 0 : MAX30100_REG_MODE_CONFIG_PWR);
>>>> +}
>>>> +
>>>> +static int max30100_buffer_postenable(struct iio_dev *indio_dev)
>>>> +{
>>>> +    struct max30100_data *data = iio_priv(indio_dev);
>>>> +
>>>> +    return max30100_set_powermode(data, true);
>>>> +}
>>>> +
>>>> +static int max30100_buffer_predisable(struct iio_dev *indio_dev)
>>>> +{
>>>> +    struct max30100_data *data = iio_priv(indio_dev);
>>>> +
>>>> +    return max30100_set_powermode(data, false);
>>>> +}
>>>> +
>>>> +static const struct iio_buffer_setup_ops max30100_buffer_setup_ops = {
>>>> +    .postenable = max30100_buffer_postenable,
>>>> +    .predisable = max30100_buffer_predisable,
>>>> +};
>>>> +
>>>> +static inline int max30100_fifo_is_empty(struct max30100_data *data)
>>>> +{
>>>> +    int ret, val;
>>>> +
>>>> +    ret = regmap_read(data->regmap, MAX30100_REG_INT_STATUS, &val);
>>>> +    if (ret)
>>>> +            return ret;
>>>> +
>>>> +    return !!(val >> 4);
>> You don't really need the !! as you only check it's != 0 later...
>> I guess you could argue this makes it obvious it is a boolean though...
>>>> +}
>>>> +
>>>> +static irqreturn_t max30100_interrupt_handler(int irq, void *private)
>>>> +{
>>>> +    struct iio_dev *indio_dev = private;
>>>> +    struct max30100_data *data = iio_priv(indio_dev);
>>>> +    int ret;
>>>> +
>>>> +    mutex_lock(&data->lock);
>>>> +
>>>> +    while (max30100_fifo_is_empty(data) != 0) {
>>>> +            ret = regmap_bulk_read(data->regmap, MAX30100_REG_FIFO_DATA,
>>>> +                                  &data->buffer, 4);
>>>> +
>>>> +            if (ret)
>>>> +                    goto err_read;
>>>> +
>> use the local copy (ultimately private) instead of the version in data.
>>>> +            iio_push_to_buffers(data->indio_dev, data->buffer);
>>>> +    }
>>>> +
>>>> +err_read:
>>>> +    mutex_unlock(&data->lock);
>>>> +
>>>> +    return IRQ_HANDLED;
>>>> +}
>>>> +
>>>> +static int max30100_chip_init(struct max30100_data *data)
>>>> +{
>>>> +    int ret;
>>>> +
>>>> +    /* RED IR LED = 24mA, IR LED = 50mA */
>>>> +    ret = regmap_write(data->regmap, MAX30100_REG_LED_CONFIG,
>>>> +                            (MAX30100_REG_LED_CONFIG_24MA <<
>>>> +                             MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) |
>>>> +                             MAX30100_REG_LED_CONFIG_50MA);
>>>> +    if (ret)
>>>> +            return ret;
>>>> +
>>>> +    /* enable hi-res SPO2 readings with 100 samples a second */
>>>> +    ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG,
>>>> +                            MAX30100_REG_SPO2_CONFIG_HI_RES_EN |
>>>> +                            MAX30100_REG_SPO2_CONFIG_100HZ |
>>>> +                            MAX30100_REG_SPO2_CONFIG_1600US);
>>>> +    if (ret)
>>>> +            return ret;
>>>> +
>>>> +    /* enable SPO2 + HR mode */
>>>> +    ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
>>>> +                            MAX30100_REG_MODE_CONFIG_MODE_MASK,
>>>> +                            MAX30100_REG_MODE_CONFIG_MODE_HR_EN |
>>>> +                            MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN);
>>>> +    if (ret)
>>>> +            return ret;
>>>> +
>>>> +    /* enable SPO2 + HR interrupts */
>>>> +    return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE,
>>>> +                            MAX30100_REG_INT_ENABLE_MASK,
>>>> +                            (MAX30100_REG_INT_ENABLE_HR_EN |
>>>> +                             MAX30100_REG_INT_ENABLE_SPO2_EN)
>>>> +                             << MAX30100_REG_INT_ENABLE_MASK_SHIFT);
>>>> +}
>>>> +
>>>> +static int max30100_read_temp(struct max30100_data *data, int *val)
>>>> +{
>>>> +    int ret;
>>>> +    int reg;
>>>> +
>>>> +    ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, &reg);
>>>> +    if (ret < 0)
>>>> +            return ret;
>>>> +    *val = reg << 4;
>>>
>>> note that this is a signed value; I think negative temperatures are not
>>> processed correctly
>> Definitely looks like it's missing a sign extend to me as well!
> 
> D'oh! Yeah you are correct!
> 
>>>
>>>> +
>>>> +    ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, &reg);
>>>> +    if (ret < 0)
>>>> +            return ret;
>>>> +    *val |= reg & 0xf;
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int max30100_get_temp(struct max30100_data *data, int *val)
>>>> +{
>>>> +    int ret;
>>>> +    int tries = 3;
>>>> +
>>>> +    /* start acquisition */
>>>> +    ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
>>>> +                             MAX30100_REG_MODE_CONFIG_TEMP_EN,
>>>> +                             MAX30100_REG_MODE_CONFIG_TEMP_EN);
>>>> +    if (ret)
>>>> +            return ret;
>>>> +
>>>> +    while (tries--) {
>>>> +            int reg;
>> Could use the interrupt that indicates temperature is ready...
>>
>> Why have you chosen not to? (might well be sensible but you want
>> to have documentation somewhere here to explain why.)
>>
>> I guess it's because it is likely to be an occasional out of band reading
>> and you don't want to complicate the interrupt handling?
> 
> Yeah I didn't want to complicate the interrupt handler. Pretty much
> the only reason I did it that way...
> Should I document that in a comment?
Yes.

> 
>>>> +
>>>> +            usleep_range(29000, 40000);
>>>> +
>>>> +            ret = regmap_read(data->regmap, MAX30100_REG_MODE_CONFIG, &reg);
>>>> +            if (ret < 0)
>>>> +                    break;
>>>> +
>>>> +            /* bit reset to zero when reading is ready */
>>>> +            if (!(reg & MAX30100_REG_MODE_CONFIG_TEMP_EN)) {
>>>> +                    ret = max30100_read_temp(data, val);
>>>> +                    break;
>>>> +            }
>>>> +            ret = -EIO;
>>>> +    }
>>>> +
>>>> +    return ret;
>>>> +}
>>>> +
>>>> +static int max30100_read_raw(struct iio_dev *indio_dev,
>>>> +                         struct iio_chan_spec const *chan,
>>>> +                         int *val, int *val2, long mask)
>>>> +{
>>>> +    struct max30100_data *data = iio_priv(indio_dev);
>>>> +    int ret = -EINVAL;
>>>> +
>>>> +    mutex_lock(&indio_dev->mlock);
>>>> +
>>>> +    /* temperature reading can only be acquired while engine is running */
>>>> +    if (!iio_buffer_enabled(indio_dev) && mask == IIO_CHAN_INFO_RAW) {
>>>> +            ret = -EAGAIN;
>> Possibly -EBUSY.  EAGAIN tends to lead to usespace software immediately
>> trying to read again whereas EBUSY tends to imply there is a 'reason' beyond
>> just 'not now'.
>>
>> Not a particularly clear cut case however.
>>
>> Reorder this to be under the switch (mask) case IIO_CHAN_INFO_RAW though
>> and the code flow will be simpler as you won't need to check we are trying
>> a raw read twice.
> 
> Got it!
>>
>>>> +            goto error_again;
>>>> +    }
>>>> +
>>>> +    switch (mask) {
>>>> +    case IIO_CHAN_INFO_RAW:
>>>> +            ret = max30100_get_temp(data, val);
>>>> +            if (!ret)
>>>
>>> what if ret < 0?
>>> _get_temp() checks for ret < 0
>>>
>>> INTENSITY channels cannot be raw_read?
>> It's not in the channel spec, so Matt's right here.  However
>> given this is 'unusual' it might act as a form of 'documentation'
>> to explicitly verify we have a temperature channel here.
>>
>> (Peter, for why they have no _raw access see the previous version -
>> basically there is no point in getting a single reading on this sort
>> of device - it's the processing of the waveform that allows you to
>> establish what the device is meant to be measuring.  Makes sense to
>> me).
>>>
>>>> +                    ret = IIO_VAL_INT;
>>>> +            break;
>>>> +    case IIO_CHAN_INFO_SCALE:
>>>> +            *val = 1;  /* 0.0625 */
>>>> +            *val2 = 16;
>>>> +            ret = IIO_VAL_FRACTIONAL;
>>>> +            break;
>>>> +    }
>>>> +
>>>> +error_again:
>>>> +    mutex_unlock(&indio_dev->mlock);
>>>> +
>>>> +    return ret;
>>>> +}
>>>> +
>>>> +static const struct iio_info max30100_info = {
>>>> +    .driver_module = THIS_MODULE,
>>>> +    .read_raw = max30100_read_raw,
>>>> +};
>>>> +
>>>> +static int max30100_probe(struct i2c_client *client,
>>>> +                      const struct i2c_device_id *id)
>>>> +{
>>>> +    struct max30100_data *data;
>>>> +    struct iio_buffer *buffer;
>>>> +    struct iio_dev *indio_dev;
>>>> +    int ret;
>>>> +
>>>> +    indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
>>>> +    if (!indio_dev)
>>>> +            return -ENOMEM;
>>>> +
>>>> +    buffer = devm_iio_kfifo_allocate(&client->dev);
>>>> +    if (!buffer)
>>>> +            return -ENOMEM;
>>>> +
>>>> +    iio_device_attach_buffer(indio_dev, buffer);
>>>> +
>>>> +    indio_dev->name = MAX30100_DRV_NAME;
>>>> +    indio_dev->channels = max30100_channels;
>>>> +    indio_dev->info = &max30100_info;
>>>> +    indio_dev->num_channels = ARRAY_SIZE(max30100_channels);
>>>> +    indio_dev->available_scan_masks = max30100_scan_masks;
>>>> +    indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE);
>>>> +    indio_dev->setup_ops = &max30100_buffer_setup_ops;
>>>> +
>>>> +    data = iio_priv(indio_dev);
>>>> +    data->indio_dev = indio_dev;
>>>> +
>>>> +    mutex_init(&data->lock);
>>>> +    i2c_set_clientdata(client, indio_dev);
>>>> +
>>>> +    data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config);
>>>> +    if (IS_ERR(data->regmap)) {
>>>> +            dev_err(&client->dev, "regmap initialization failed.\n");
>>>> +            return PTR_ERR(data->regmap);
>>>> +    }
>>>> +    max30100_set_powermode(data, false);
>>>> +
>>>> +    ret = max30100_chip_init(data);
>>>> +    if (ret)
>>>> +            goto error_out;
>>>> +
>>>> +    if (client->irq <= 0) {
>>>> +            dev_err(&client->dev, "no valid irq defined\n");
>>>> +            ret = -EINVAL;
>>>> +            goto error_out;
>>>> +    }
>>>> +    ret = devm_request_threaded_irq(&client->dev, client->irq,
>>>> +                                    NULL, max30100_interrupt_handler,
>>>> +                                    IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
>>>> +                                    "max30100_irq", indio_dev);
>>>> +    if (ret) {
>>>> +            dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
>>>> +            goto error_out;
>>>> +    }
>>>> +
>>>> +    return iio_device_register(indio_dev);
>>>
>>> newline here
>>>
>>>> +error_out:
>>>
>>> drop newline
>>>
>>>> +
>>>> +    return ret;
>>>> +}
>>>> +
>>>> +static int max30100_remove(struct i2c_client *client)
>>>> +{
>>>> +    struct iio_dev *indio_dev = i2c_get_clientdata(client);
>>>> +    struct max30100_data *data = iio_priv(indio_dev);
>>>> +
>>>> +    iio_device_unregister(indio_dev);
>>>> +    max30100_set_powermode(data, false);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static const struct i2c_device_id max30100_id[] = {
>>>> +    { "max30100", 0 },
>>>> +    {}
>>>> +};
>>>> +MODULE_DEVICE_TABLE(i2c, max30100_id);
>>>> +
>>>> +static const struct of_device_id max30100_dt_ids[] = {
>>>> +    { .compatible = "maxim,max30100" },
>>>> +    { }
>>>> +};
>>>> +MODULE_DEVICE_TABLE(of, max30100_dt_ids);
>>>> +
>>>> +static struct i2c_driver max30100_driver = {
>>>> +    .driver = {
>>>> +            .name   = MAX30100_DRV_NAME,
>>>> +            .of_match_table = of_match_ptr(max30100_dt_ids),
>>>> +    },
>>>> +    .probe          = max30100_probe,
>>>> +    .remove         = max30100_remove,
>>>> +    .id_table       = max30100_id,
>>>> +};
>>>> +module_i2c_driver(max30100_driver);
>>>> +
>>>> +MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
>>>> +MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor");
>>>> +MODULE_LICENSE("GPL");
>>>>
>>>
>>
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