Re: [PATCH v2 2/2] iio: health: add MAX30102 oximeter driver support

[Jonathan Cameron <jic23@kernel.org>]

On 25/01/17 07:04, Matt Ranostay wrote:
> MAX30102 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
> be processed in userspace to determine heart rate and blood oxygen
> levels. The MAX30102 part isn't completely register and functional
> compatible with the existing MAX30100 driver.
> 
> Signed-off-by: Matt Ranostay <matt@ranostay.consulting>
Really minor comment inline from me.  Would guess V3 will do the job
on this one ;)

Jonathan
> ---
>  drivers/iio/health/Kconfig    |  13 ++
>  drivers/iio/health/Makefile   |   1 +
>  drivers/iio/health/max30102.c | 485 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 499 insertions(+)
>  create mode 100644 drivers/iio/health/max30102.c
> 
> diff --git a/drivers/iio/health/Kconfig b/drivers/iio/health/Kconfig
> index c5f004a8e447..a2ecb4c94c2a 100644
> --- a/drivers/iio/health/Kconfig
> +++ b/drivers/iio/health/Kconfig
> @@ -46,6 +46,19 @@ config MAX30100
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called max30100.
>  
> +config MAX30102
> +	tristate "MAX30102 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
> +	  MAX30102 heart rate, and pulse oximeter sensor.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called max30102.
> +
>  endmenu
>  
>  endmenu
> diff --git a/drivers/iio/health/Makefile b/drivers/iio/health/Makefile
> index 9955a2ae8df1..3558f9d64954 100644
> --- a/drivers/iio/health/Makefile
> +++ b/drivers/iio/health/Makefile
> @@ -7,3 +7,4 @@
>  obj-$(CONFIG_AFE4403)		+= afe4403.o
>  obj-$(CONFIG_AFE4404)		+= afe4404.o
>  obj-$(CONFIG_MAX30100)		+= max30100.o
> +obj-$(CONFIG_MAX30102)		+= max30102.o
> diff --git a/drivers/iio/health/max30102.c b/drivers/iio/health/max30102.c
> new file mode 100644
> index 000000000000..87df1e6d712f
> --- /dev/null
> +++ b/drivers/iio/health/max30102.c
> @@ -0,0 +1,485 @@
> +/*
> + * max30102.c - Support for MAX30102 heart rate and pulse oximeter sensor
> + *
> + * Copyright (C) 2017 Matt Ranostay <matt@ranostay.consulting>
> + *
> + * 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.
> + *
> + * TODO: proximity power saving feature
> + */
> +
> +#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/of.h>
> +#include <linux/regmap.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/kfifo_buf.h>
> +
> +#define MAX30102_REGMAP_NAME	"max30102_regmap"
> +#define MAX30102_DRV_NAME	"max30102"
> +
> +#define MAX30102_REG_INT_STATUS			0x00
> +#define MAX30102_REG_INT_STATUS_PWR_RDY		BIT(0)
> +#define MAX30102_REG_INT_STATUS_PROX_INT	BIT(4)
> +#define MAX30102_REG_INT_STATUS_ALC_OVF		BIT(5)
> +#define MAX30102_REG_INT_STATUS_PPG_RDY		BIT(6)
> +#define MAX30102_REG_INT_STATUS_FIFO_RDY	BIT(7)
> +
> +#define MAX30102_REG_INT_ENABLE			0x02
> +#define MAX30102_REG_INT_ENABLE_PROX_INT_EN	BIT(4)
> +#define MAX30102_REG_INT_ENABLE_ALC_OVF_EN	BIT(5)
> +#define MAX30102_REG_INT_ENABLE_PPG_EN		BIT(6)
> +#define MAX30102_REG_INT_ENABLE_FIFO_EN		BIT(7)
> +#define MAX30102_REG_INT_ENABLE_MASK		0xf0
> +#define MAX30102_REG_INT_ENABLE_MASK_SHIFT	4
> +
> +#define MAX30102_REG_FIFO_WR_PTR		0x04
> +#define MAX30102_REG_FIFO_OVR_CTR		0x05
> +#define MAX30102_REG_FIFO_RD_PTR		0x06
> +#define MAX30102_REG_FIFO_DATA			0x07
> +#define MAX30102_REG_FIFO_DATA_ENTRY_LEN	6
> +
> +#define MAX30102_REG_FIFO_CONFIG		0x08
> +#define MAX30102_REG_FIFO_CONFIG_AVG_4SAMPLES	BIT(1)
> +#define MAX30102_REG_FIFO_CONFIG_AVG_SHIFT	5
> +#define MAX30102_REG_FIFO_CONFIG_AFULL		BIT(0)
> +
> +#define MAX30102_REG_MODE_CONFIG		0x09
> +#define MAX30102_REG_MODE_CONFIG_MODE_SPO2_EN	BIT(0)
> +#define MAX30102_REG_MODE_CONFIG_MODE_HR_EN	BIT(1)
> +#define MAX30102_REG_MODE_CONFIG_MODE_MASK	0x03
> +#define MAX30102_REG_MODE_CONFIG_PWR		BIT(7)
> +
> +#define MAX30102_REG_SPO2_CONFIG		0x0a
> +#define MAX30102_REG_SPO2_CONFIG_PULSE_411_US	0x03
> +#define MAX30102_REG_SPO2_CONFIG_SR_400HZ	0x03
> +#define MAX30102_REG_SPO2_CONFIG_SR_MASK	0x07
> +#define MAX30102_REG_SPO2_CONFIG_SR_MASK_SHIFT	2
> +#define MAX30102_REG_SPO2_CONFIG_ADC_4096_STEPS	BIT(0)
> +#define MAX30102_REG_SPO2_CONFIG_ADC_MASK_SHIFT	4
> +
> +#define MAX30102_REG_RED_LED_CONFIG		0x0c
> +#define MAX30102_REG_IR_LED_CONFIG		0x0d
> +
> +#define MAX30102_REG_TEMP_CONFIG		0x21
> +#define MAX30102_REG_TEMP_CONFIG_TEMP_EN	BIT(0)
> +
> +#define MAX30102_REG_TEMP_INTEGER		0x1f
> +#define MAX30102_REG_TEMP_FRACTION		0x20
> +
> +struct max30102_data {
> +	struct i2c_client *client;
> +	struct iio_dev *indio_dev;
> +	struct mutex lock;
> +	struct regmap *regmap;
> +
> +	u8 buffer[8];
> +	__be32 processed_buffer[2]; /* 2 x 18-bit (padded to 32-bits) */
> +};
> +
> +static const struct regmap_config max30102_regmap_config = {
> +	.name = MAX30102_REGMAP_NAME,
> +
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +};
> +
> +static const unsigned long max30102_scan_masks[] = {0x3, 0};
> +
> +static const struct iio_chan_spec max30102_channels[] = {
> +	{
> +		.type = IIO_INTENSITY,
> +		.channel2 = IIO_MOD_LIGHT_RED,
> +		.modified = 1,
> +
> +		.scan_index = 0,
> +		.scan_type = {
> +			.sign = 'u',
> +			.shift = 14,
> +			.realbits = 18,
> +			.storagebits = 32,
> +			.endianness = IIO_BE,
> +		},
> +	},
> +	{
> +		.type = IIO_INTENSITY,
> +		.channel2 = IIO_MOD_LIGHT_IR,
> +		.modified = 1,
> +
> +		.scan_index = 1,
> +		.scan_type = {
> +			.sign = 'u',
> +			.shift = 14,
> +			.realbits = 18,
> +			.storagebits = 32,
> +			.endianness = IIO_BE,
> +		},
> +	},
> +	{
> +		.type = IIO_TEMP,
> +		.info_mask_separate =
> +			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
> +		.scan_index = -1,
> +	},
> +};
> +
> +static int max30102_set_powermode(struct max30102_data *data, bool state)
> +{
> +	return regmap_update_bits(data->regmap, MAX30102_REG_MODE_CONFIG,
> +				  MAX30102_REG_MODE_CONFIG_PWR,
> +				  state ? 0 : MAX30102_REG_MODE_CONFIG_PWR);
> +}
> +
> +static int max30102_buffer_postenable(struct iio_dev *indio_dev)
> +{
> +	struct max30102_data *data = iio_priv(indio_dev);
> +
> +	return max30102_set_powermode(data, true);
> +}
> +
> +static int max30102_buffer_predisable(struct iio_dev *indio_dev)
> +{
> +	struct max30102_data *data = iio_priv(indio_dev);
> +
> +	return max30102_set_powermode(data, false);
> +}
> +
> +static const struct iio_buffer_setup_ops max30102_buffer_setup_ops = {
> +	.postenable = max30102_buffer_postenable,
> +	.predisable = max30102_buffer_predisable,
> +};
> +
> +static inline int max30102_fifo_count(struct max30102_data *data)
> +{
> +	unsigned int val;
> +	int ret;
> +
> +	ret = regmap_read(data->regmap, MAX30102_REG_INT_STATUS, &val);
> +	if (ret)
> +		return ret;
> +
> +	/* FIFO has one sample slot left */
> +	if (val & MAX30102_REG_INT_STATUS_FIFO_RDY)
> +		return 1;
> +
> +	return 0;
> +}
> +
> +static int max30102_read_measurement(struct max30102_data *data)
> +{
> +	int ret;
> +	u8 *buffer = (u8 *) &data->buffer;
> +
> +	ret = i2c_smbus_read_i2c_block_data(data->client,
> +					    MAX30102_REG_FIFO_DATA,
> +					    MAX30102_REG_FIFO_DATA_ENTRY_LEN,
> +					    buffer);
> +
> +	memcpy(&data->processed_buffer[0], &buffer[0], 3);
> +	memcpy(&data->processed_buffer[1], &buffer[3], 3);
> +
> +	return (ret == MAX30102_REG_FIFO_DATA_ENTRY_LEN) ? 0 : -EINVAL;
> +}
> +
> +static irqreturn_t max30102_interrupt_handler(int irq, void *private)
> +{
> +	struct iio_dev *indio_dev = private;
> +	struct max30102_data *data = iio_priv(indio_dev);
> +	int ret, cnt = 0;
> +
> +	mutex_lock(&data->lock);
> +
> +	while (cnt || (cnt = max30102_fifo_count(data)) > 0) {
> +		ret = max30102_read_measurement(data);
> +		if (ret)
> +			break;
> +
> +		iio_push_to_buffers(data->indio_dev, data->processed_buffer);
> +		cnt--;
> +	}
> +
> +	mutex_unlock(&data->lock);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int max30102_get_current_idx(unsigned int val, int *reg)
> +{
> +	/* each step is 0.200 mA */
> +	*reg = val / 200;
> +
> +	return *reg > 0xff ? -EINVAL : 0;
> +}
> +
> +static int max30102_led_init(struct max30102_data *data)
> +{
> +	struct device *dev = &data->client->dev;
> +	struct device_node *np = dev->of_node;
> +	unsigned int val;
> +	int reg, ret;
> +
> +	ret = of_property_read_u32(np, "maxim,red-led-current-microamp", &val);
> +	if (ret) {
> +		dev_info(dev, "no red-led-current-microamp set\n");
> +
> +		/* Default to 7 mA RED LED */
> +		val = 7000;
> +	}
> +
> +	ret = max30102_get_current_idx(val, &reg);
> +	if (ret) {
> +		dev_err(dev, "invalid RED LED current setting %d\n", val);
> +		return ret;
> +	}
> +
> +	ret = regmap_write(data->regmap, MAX30102_REG_RED_LED_CONFIG, reg);
> +	if (ret)
> +		return ret;
> +
> +	ret = of_property_read_u32(np, "maxim,ir-led-current-microamp", &val);
> +	if (ret) {
> +		dev_info(dev, "no ir-led-current-microamp set\n");
> +
> +		/* Default to 7 mA IR LED */
> +		val = 7000;
> +	}
> +
> +	ret = max30102_get_current_idx(val, &reg);
> +	if (ret) {
> +		dev_err(dev, "invalid IR LED current setting %d", val);
> +		return ret;
> +	}
> +
> +	return regmap_write(data->regmap, MAX30102_REG_IR_LED_CONFIG, reg);
> +}
> +
> +static int max30102_chip_init(struct max30102_data *data)
> +{
> +	int ret;
> +
> +	/* setup LED current settings */
> +	ret = max30102_led_init(data);
> +	if (ret)
> +		return ret;
> +
> +	/* enable 18-bit HR + SPO2 readings at 400Hz */
> +	ret = regmap_write(data->regmap, MAX30102_REG_SPO2_CONFIG,
> +				(MAX30102_REG_SPO2_CONFIG_ADC_4096_STEPS
> +				 << MAX30102_REG_SPO2_CONFIG_ADC_MASK_SHIFT) |
> +				(MAX30102_REG_SPO2_CONFIG_SR_400HZ
> +				 << MAX30102_REG_SPO2_CONFIG_SR_MASK_SHIFT) |
> +				 MAX30102_REG_SPO2_CONFIG_PULSE_411_US);
> +	if (ret)
> +		return ret;
> +
> +	/* enable SPO2 mode */
> +	ret = regmap_update_bits(data->regmap, MAX30102_REG_MODE_CONFIG,
> +				 MAX30102_REG_MODE_CONFIG_MODE_MASK,
> +				 MAX30102_REG_MODE_CONFIG_MODE_HR_EN |
> +				 MAX30102_REG_MODE_CONFIG_MODE_SPO2_EN);
> +	if (ret)
> +		return ret;
> +
> +	/* average 4 samples + generate FIFO interrupt */
> +	ret = regmap_write(data->regmap, MAX30102_REG_FIFO_CONFIG,
> +				(MAX30102_REG_FIFO_CONFIG_AVG_4SAMPLES
> +				 << MAX30102_REG_FIFO_CONFIG_AVG_SHIFT) |
> +				 MAX30102_REG_FIFO_CONFIG_AFULL);
> +	if (ret)
> +		return ret;
> +
> +	/* enable FIFO interrupt */
> +	return regmap_update_bits(data->regmap, MAX30102_REG_INT_ENABLE,
> +				 MAX30102_REG_INT_ENABLE_MASK,
> +				 MAX30102_REG_INT_ENABLE_FIFO_EN);
> +}
> +
> +static int max30102_read_temp(struct max30102_data *data, int *val)
> +{
> +	int ret;
> +	unsigned int reg;
> +
> +	ret = regmap_read(data->regmap, MAX30102_REG_TEMP_INTEGER, &reg);
> +	if (ret < 0)
> +		return ret;
> +	*val = reg << 4;
> +
> +	ret = regmap_read(data->regmap, MAX30102_REG_TEMP_FRACTION, &reg);
> +	if (ret < 0)
> +		return ret;
> +
> +	*val |= reg & 0xf;
> +	*val = sign_extend32(*val, 11);
> +
> +	return 0;
> +}
> +
> +static int max30102_get_temp(struct max30102_data *data, int *val)
> +{
> +	int ret;
> +
> +	/* start acquisition */
> +	ret = regmap_update_bits(data->regmap, MAX30102_REG_TEMP_CONFIG,
> +				 MAX30102_REG_TEMP_CONFIG_TEMP_EN,
> +				 MAX30102_REG_TEMP_CONFIG_TEMP_EN);
> +	if (ret)
> +		return ret;
> +
> +	msleep(35);
> +
> +	return max30102_read_temp(data, val);
> +}
> +
> +static int max30102_read_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan,
> +			     int *val, int *val2, long mask)
> +{
> +	struct max30102_data *data = iio_priv(indio_dev);
> +	int ret = -EINVAL;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		/*
> +		 * Temperature reading can only be acquired while engine
> +		 * is running
> +		 */
> +		mutex_lock(&indio_dev->mlock);
> +
> +		if (!iio_buffer_enabled(indio_dev))
> +			ret = -EAGAIN;
Issue with this is typically userspace will just try having another go
immediately.  -EBUSY would be normal way of indicating not in a state
where it can do this, but here it's kind of inverted.  Not obvious!
> +		else {
> +			ret = max30102_get_temp(data, val);
> +			if (!ret)
> +				ret = IIO_VAL_INT;
> +		}
> +
> +		mutex_unlock(&indio_dev->mlock);
> +		break;
> +	case IIO_CHAN_INFO_SCALE:
> +		*val = 1;  /* 0.0625 */
> +		*val2 = 16;
> +		ret = IIO_VAL_FRACTIONAL;
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static const struct iio_info max30102_info = {
> +	.driver_module = THIS_MODULE,
> +	.read_raw = max30102_read_raw,
> +};
> +
> +static int max30102_probe(struct i2c_client *client,
> +			  const struct i2c_device_id *id)
> +{
> +	struct max30102_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 = MAX30102_DRV_NAME;
> +	indio_dev->channels = max30102_channels;
> +	indio_dev->info = &max30102_info;
> +	indio_dev->num_channels = ARRAY_SIZE(max30102_channels);
> +	indio_dev->available_scan_masks = max30102_scan_masks;
> +	indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE);
> +	indio_dev->setup_ops = &max30102_buffer_setup_ops;
> +
> +	data = iio_priv(indio_dev);
> +	data->indio_dev = indio_dev;
> +	data->client = client;
> +
> +	mutex_init(&data->lock);
> +	i2c_set_clientdata(client, indio_dev);
> +
> +	data->regmap = devm_regmap_init_i2c(client, &max30102_regmap_config);
> +	if (IS_ERR(data->regmap)) {
> +		dev_err(&client->dev, "regmap initialization failed.\n");
> +		return PTR_ERR(data->regmap);
> +	}
> +	max30102_set_powermode(data, false);
> +
> +	ret = max30102_chip_init(data);
> +	if (ret)
> +		return ret;
> +
> +	if (client->irq <= 0) {
> +		dev_err(&client->dev, "no valid irq defined\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = devm_request_threaded_irq(&client->dev, client->irq,
> +					NULL, max30102_interrupt_handler,
> +					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> +					"max30102_irq", indio_dev);
> +	if (ret) {
> +		dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
> +		return ret;
> +	}
> +
> +	return iio_device_register(indio_dev);
> +}
> +
> +static int max30102_remove(struct i2c_client *client)
> +{
> +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +	struct max30102_data *data = iio_priv(indio_dev);
> +
> +	iio_device_unregister(indio_dev);
> +	max30102_set_powermode(data, false);
> +
> +	return 0;
> +}
> +
> +static const struct i2c_device_id max30102_id[] = {
> +	{ "max30102", 0 },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, max30102_id);
> +
> +static const struct of_device_id max30102_dt_ids[] = {
> +	{ .compatible = "maxim,max30102" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, max30102_dt_ids);
> +
> +static struct i2c_driver max30102_driver = {
> +	.driver = {
> +		.name	= MAX30102_DRV_NAME,
> +		.of_match_table	= of_match_ptr(max30102_dt_ids),
> +	},
> +	.probe		= max30102_probe,
> +	.remove		= max30102_remove,
> +	.id_table	= max30102_id,
> +};
> +module_i2c_driver(max30102_driver);
> +
> +MODULE_AUTHOR("Matt Ranostay <matt@ranostay.consulting>");
> +MODULE_DESCRIPTION("MAX30102 heart rate and pulse oximeter sensor");
> +MODULE_LICENSE("GPL");
>