Re: [PATCH 2/3] iio: mpl3115: add support for DRDY interrupt

["Nuno Sá" <noname.nuno@gmail.com>]

On Sun, 2025-09-21 at 15:33 +0200, Antoni Pokusinski wrote:
> MPL3115 sensor features a "data ready" interrupt which indicates the
> presence of new measurements.
> 
> Signed-off-by: Antoni Pokusinski <apokusinski01@gmail.com>
> ---
>  drivers/iio/pressure/mpl3115.c | 167 ++++++++++++++++++++++++++++++++-
>  1 file changed, 162 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iio/pressure/mpl3115.c b/drivers/iio/pressure/mpl3115.c
> index 579da60ef441..cf34de8f0d7e 100644
> --- a/drivers/iio/pressure/mpl3115.c
> +++ b/drivers/iio/pressure/mpl3115.c
> @@ -7,7 +7,7 @@
>   * (7-bit I2C slave address 0x60)
>   *
>   * TODO: FIFO buffer, altimeter mode, oversampling, continuous mode,
> - * interrupts, user offset correction, raw mode
> + * user offset correction, raw mode
>   */
>  
>  #include <linux/module.h>
> @@ -17,26 +17,45 @@
>  #include <linux/iio/trigger_consumer.h>
>  #include <linux/iio/buffer.h>
>  #include <linux/iio/triggered_buffer.h>
> +#include <linux/iio/trigger.h>
>  #include <linux/delay.h>
> +#include <linux/property.h>
>  
>  #define MPL3115_STATUS 0x00
>  #define MPL3115_OUT_PRESS 0x01 /* MSB first, 20 bit */
>  #define MPL3115_OUT_TEMP 0x04 /* MSB first, 12 bit */
>  #define MPL3115_WHO_AM_I 0x0c
> +#define MPL3115_INT_SOURCE 0x12
> +#define MPL3115_PT_DATA_CFG 0x13
>  #define MPL3115_CTRL_REG1 0x26
> +#define MPL3115_CTRL_REG3 0x28
> +#define MPL3115_CTRL_REG4 0x29
> +#define MPL3115_CTRL_REG5 0x2a
>  
>  #define MPL3115_DEVICE_ID 0xc4
>  
>  #define MPL3115_STATUS_PRESS_RDY BIT(2)
>  #define MPL3115_STATUS_TEMP_RDY BIT(1)
>  
> +#define MPL3115_CTRL_INT_SRC_DRDY BIT(7)
> +
> +#define MPL3115_PT_DATA_EVENT_ALL (BIT(2) | BIT(1) | BIT(0))
> +
>  #define MPL3115_CTRL_RESET BIT(2) /* software reset */
>  #define MPL3115_CTRL_OST BIT(1) /* initiate measurement */
>  #define MPL3115_CTRL_ACTIVE BIT(0) /* continuous measurement */
>  #define MPL3115_CTRL_OS_258MS (BIT(5) | BIT(4)) /* 64x oversampling */
>  
> +#define MPL3115_CTRL_IPOL1 BIT(5)
> +#define MPL3115_CTRL_IPOL2 BIT(1)
> +
> +#define MPL3115_CTRL_INT_EN_DRDY BIT(7)
> +
> +#define MPL3115_CTRL_INT_CFG_DRDY BIT(7)
> +
>  struct mpl3115_data {
>  	struct i2c_client *client;
> +	struct iio_trigger *drdy_trig;
>  	struct mutex lock;
>  	u8 ctrl_reg1;
>  };
> @@ -164,10 +183,12 @@ static irqreturn_t mpl3115_trigger_handler(int irq, void
> *p)
>  	int ret, pos = 0;
>  
>  	mutex_lock(&data->lock);
> -	ret = mpl3115_request(data);
> -	if (ret < 0) {
> -		mutex_unlock(&data->lock);
> -		goto done;
> +	if (!(data->ctrl_reg1 & MPL3115_CTRL_ACTIVE)) {
> +		ret = mpl3115_request(data);
> +		if (ret < 0) {
> +			mutex_unlock(&data->lock);
> +			goto done;
> +		}
>  	}
>  
>  	if (test_bit(0, indio_dev->active_scan_mask)) {
> @@ -228,10 +249,142 @@ static const struct iio_chan_spec mpl3115_channels[] =
> {
>  	IIO_CHAN_SOFT_TIMESTAMP(2),
>  };
>  
> +static irqreturn_t mpl3115_interrupt_handler(int irq, void *private)
> +{
> +	struct iio_dev *indio_dev = private;
> +	struct mpl3115_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = i2c_smbus_read_byte_data(data->client, MPL3115_INT_SOURCE);
> +	if (ret < 0)
> +		return IRQ_HANDLED;
> +
> +	if (!(ret & MPL3115_CTRL_INT_SRC_DRDY))
> +		return IRQ_NONE;
> +
> +	iio_trigger_poll_nested(data->drdy_trig);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int mpl3115_set_trigger_state(struct iio_trigger *trig, bool state)
> +{
> +	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
> +	struct mpl3115_data *data = iio_priv(indio_dev);
> +	int ret;
> +	u8 ctrl_reg1 = data->ctrl_reg1;
> +
> +	if (state)
> +		ctrl_reg1 |= MPL3115_CTRL_ACTIVE;
> +	else
> +		ctrl_reg1 &= ~MPL3115_CTRL_ACTIVE;
> +
> +	guard(mutex)(&data->lock);
> +

As Andy pointed out, you should have a precursor patch converting the complete
driver to use the cleanup logic.

Another nice cleanup you could do (if you want of course) would be to get rid of
mpl3115_remove().

> +	ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
> +					ctrl_reg1);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG4,
> +					state ? MPL3115_CTRL_INT_EN_DRDY :
> 0);
> +	if (ret < 0)
> +		goto reg1_cleanup;
> +
> +	data->ctrl_reg1 = ctrl_reg1;
> +
> +	return 0;
> +
> +reg1_cleanup:
> +	i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
> +				  data->ctrl_reg1);
> +	return ret;
> +}
> +
> +static const struct iio_trigger_ops mpl3115_trigger_ops = {
> +	.set_trigger_state = mpl3115_set_trigger_state,
> +};
> +
>  static const struct iio_info mpl3115_info = {
>  	.read_raw = &mpl3115_read_raw,
>  };
>  
> +static int mpl3115_trigger_probe(struct mpl3115_data *data,
> +				 struct iio_dev *indio_dev)
> +{
> +	struct fwnode_handle *fwnode;
> +	int ret, irq, irq_type;
> +	bool act_high, is_int2 = false;
> +
> +	fwnode = dev_fwnode(&data->client->dev);
> +	if (!fwnode)
> +		return -ENODEV;
> +

And to add to Andy's review, fwnode_irq_get_byname() will give you an error
anyways if !fwnode.

> +	irq = fwnode_irq_get_byname(fwnode, "INT1");
> +	if (irq < 0) {
> +		irq = fwnode_irq_get_byname(fwnode, "INT2");
> +		if (irq < 0)
> +			return 0;
> +
> +		is_int2 = true;
> +	}
> +
> +	irq_type = irq_get_trigger_type(irq);
> +	switch (irq_type) {
> +	case IRQF_TRIGGER_RISING:
> +		act_high = true;
> +		break;
> +	case IRQF_TRIGGER_FALLING:
> +		act_high = false;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	ret = i2c_smbus_write_byte_data(data->client, MPL3115_PT_DATA_CFG,
> +					MPL3115_PT_DATA_EVENT_ALL);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (!is_int2) {
> +		ret = i2c_smbus_write_byte_data(data->client,
> +						MPL3115_CTRL_REG5,
> +						MPL3115_CTRL_INT_CFG_DRDY);
> +		if (ret)
> +			return ret;
> +	}
> +	if (act_high) {
> +		ret = i2c_smbus_write_byte_data(data->client,
> +						MPL3115_CTRL_REG3,
> +						is_int2 ? MPL3115_CTRL_IPOL2
> :
> +							 
> MPL3115_CTRL_IPOL1);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	data->drdy_trig = devm_iio_trigger_alloc(&data->client->dev,
> +						 "%s-dev%d",
> +						 indio_dev->name,
> +						 iio_device_id(indio_dev));
> +	if (!data->drdy_trig)
> +		return -ENOMEM;
> +
> +	data->drdy_trig->ops = &mpl3115_trigger_ops;
> +	iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
> +	ret = iio_trigger_register(data->drdy_trig);

devm_iio_trigger_register()

- Nuno Sá

> +	if (ret)
> +		return ret;
> +
> +	indio_dev->trig = iio_trigger_get(data->drdy_trig);
> +
> +	return devm_request_threaded_irq(&data->client->dev, irq,
> +					 NULL,
> +					 mpl3115_interrupt_handler,
> +					 IRQF_ONESHOT,
> +					 "mpl3115_irq",
> +					 indio_dev);
> +}
> +
>  static int mpl3115_probe(struct i2c_client *client)
>  {
>  	const struct i2c_device_id *id = i2c_client_get_device_id(client);
> @@ -271,6 +424,10 @@ static int mpl3115_probe(struct i2c_client *client)
>  	if (ret < 0)
>  		return ret;
>  
> +	ret = mpl3115_trigger_probe(data, indio_dev);
> +	if (ret)
> +		return ret;
> +
>  	ret = iio_triggered_buffer_setup(indio_dev, NULL,
>  		mpl3115_trigger_handler, NULL);
>  	if (ret < 0)