Re: [PATCH] iio: chemical: ccs811: Add support for data ready trigger

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 17 Aug 2017 14:39:26 +0300
Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com> wrote:

> Add data ready trigger for hardware interrupts that notify us when
> new measurement samples are available.
> 
> Signed-off-by: Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com>
> ---
> Note: This patch depends on:
> [PATCH v2] iio: chemical: ccs811: Add triggered buffer support
> 
>  drivers/iio/chemical/ccs811.c | 93 ++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 92 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/chemical/ccs811.c b/drivers/iio/chemical/ccs811.c
> index b59994d..0fd617a 100644
> --- a/drivers/iio/chemical/ccs811.c
> +++ b/drivers/iio/chemical/ccs811.c
> @@ -23,6 +23,7 @@
>  #include <linux/i2c.h>
>  #include <linux/iio/iio.h>
>  #include <linux/iio/buffer.h>
> +#include <linux/iio/trigger.h>
>  #include <linux/iio/triggered_buffer.h>
>  #include <linux/iio/trigger_consumer.h>
>  #include <linux/module.h>
> @@ -60,8 +61,13 @@
>  #define CCS811_MODE_IAQ_60SEC	0x30
>  #define CCS811_MODE_RAW_DATA	0x40
> 
> +#define CCS811_MEAS_MODE_THRESH		BIT(2)
> +#define CCS811_MEAS_MODE_INTERRUPT	BIT(3)
> +
>  #define CCS811_VOLTAGE_MASK	0x3FF
> 
> +#define CCS811_IRQ_NAME "ccs811_irq"
> +
>  struct ccs811_reading {
>  	__be16 co2;
>  	__be16 voc;
> @@ -74,6 +80,7 @@ struct ccs811_data {
>  	struct i2c_client *client;
>  	struct mutex lock; /* Protect readings */
>  	struct ccs811_reading buffer;
> +	struct iio_trigger *drdy_trig;
>  };
> 
>  static const struct iio_chan_spec ccs811_channels[] = {
> @@ -274,6 +281,54 @@ static int ccs811_read_raw(struct iio_dev *indio_dev,
>  	.driver_module = THIS_MODULE,
>  };
> 
> +static int ccs811_set_trigger_state(struct iio_trigger *trig,
> +				    bool state)
> +{
> +	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
> +	struct ccs811_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = i2c_smbus_read_byte_data(data->client, CCS811_MEAS_MODE);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (state)
> +		ret |= CCS811_MEAS_MODE_INTERRUPT;
> +	else
> +		ret &= ~CCS811_MEAS_MODE_INTERRUPT;
> +
> +	if (data->drdy_trig == trig)
> +		ret &= ~CCS811_MEAS_MODE_THRESH;
> +
> +	return i2c_smbus_write_byte_data(data->client, CCS811_MEAS_MODE, ret);
> +}
> +
> +static const struct iio_trigger_ops ccs811_trigger_ops = {
> +	.set_trigger_state = ccs811_set_trigger_state,
> +	.owner = THIS_MODULE,
> +};
> +
> +static irqreturn_t ccs811_interrupt_handler(int irq, void *p)
> +{
How does this differ from the interrupt handler that was added in
the previous patch?

For a dataready trigger I'd be expecting to see some calls into
the triggering core. 

In particular an iio_trigger_poll call.

It is fine to not use the trigger infrastructure at all if the
device doesn'g fit.  However as far as I can tell this one does.

> +	struct iio_dev *indio_dev = p;
> +	struct ccs811_data *data = iio_priv(indio_dev);
> +	u16 buf[8]; /* u16 eCO2 + u16 TVOC + padding + 8 byte timestamp */
> +	int ret;
> +
> +	ret = i2c_smbus_read_i2c_block_data(data->client,
> +					    CCS811_ALG_RESULT_DATA, 4,
> +					    (u8 *)&buf);
> +	if (ret != 4) {
> +		dev_err(&data->client->dev, "cannot read sensor data\n");
> +		goto err;
> +	}
> +
> +	iio_push_to_buffers_with_timestamp(indio_dev, buf,
> +					   iio_get_time_ns(indio_dev));
> +err:
> +	return IRQ_HANDLED;
> +}
> +
>  static irqreturn_t ccs811_trigger_handler(int irq, void *p)
>  {
>  	struct iio_poll_func *pf = p;
> @@ -347,16 +402,48 @@ static int ccs811_probe(struct i2c_client *client,
>  	indio_dev->dev.parent = &client->dev;
>  	indio_dev->name = id->name;
>  	indio_dev->info = &ccs811_info;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> 
>  	indio_dev->channels = ccs811_channels;
>  	indio_dev->num_channels = ARRAY_SIZE(ccs811_channels);
> 
> +	if (client->irq > 0) {
> +		ret = devm_request_threaded_irq(&client->dev, client->irq,
> +						NULL,
> +						ccs811_interrupt_handler,
> +						IRQF_TRIGGER_FALLING |
> +						IRQF_ONESHOT,
> +						CCS811_IRQ_NAME, indio_dev);
> +		if (ret) {
> +			dev_err(&client->dev, "irq request error %d\n", -ret);
> +			goto err_poweroff;
> +		}
> +
> +		data->drdy_trig = devm_iio_trigger_alloc(&client->dev,
> +							 "%s-dev%d",
> +							 indio_dev->name,
> +							 indio_dev->id);
> +		if (!data->drdy_trig) {
> +			ret = -ENOMEM;
> +			goto err_poweroff;
> +		}
> +
> +		data->drdy_trig->dev.parent = &client->dev;
> +		data->drdy_trig->ops = &ccs811_trigger_ops;
> +		iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
> +		indio_dev->trig = data->drdy_trig;
> +		iio_trigger_get(indio_dev->trig);
> +		ret = iio_trigger_register(data->drdy_trig);
> +		if (ret)
> +			goto err_poweroff;
> +	}
> +
>  	ret = iio_triggered_buffer_setup(indio_dev, NULL,
>  					 ccs811_trigger_handler, NULL);
> 
>  	if (ret < 0) {
>  		dev_err(&client->dev, "triggered buffer setup failed\n");
> -		goto err_poweroff;
> +		goto err_trigger_unregister;
>  	}
> 
>  	ret = iio_device_register(indio_dev);
> @@ -368,6 +455,8 @@ static int ccs811_probe(struct i2c_client *client,
> 
>  err_buffer_cleanup:
>  	iio_triggered_buffer_cleanup(indio_dev);
> +err_trigger_unregister:
> +	iio_trigger_unregister(data->drdy_trig);
>  err_poweroff:
>  	i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE, CCS811_MODE_IDLE);
> 
> @@ -377,9 +466,11 @@ static int ccs811_probe(struct i2c_client *client,
>  static int ccs811_remove(struct i2c_client *client)
>  {
>  	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> +	struct ccs811_data *data = iio_priv(indio_dev);
> 
>  	iio_device_unregister(indio_dev);
>  	iio_triggered_buffer_cleanup(indio_dev);
> +	iio_trigger_unregister(data->drdy_trig);
> 
>  	return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
>  					 CCS811_MODE_IDLE);
> --
> 1.9.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html