Re: [PATCH V2 8/8] iio: mma8452: Add support for interrupt driven triggers.

[Jonathan Cameron <jic23@kernel.org>]

On 29/07/14 10:01, Martin Fuzzey wrote:
> Implement interrupt driven trigger for data ready.
> This allows more efficient access to the sample data.
>
> Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com>
More or less fine - few little bits inline.

J
> ---
>  drivers/iio/accel/mma8452.c |   91 ++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 85 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
> index 62589f9..7ccc369 100644
> --- a/drivers/iio/accel/mma8452.c
> +++ b/drivers/iio/accel/mma8452.c
> @@ -18,6 +18,8 @@
>  #include <linux/iio/sysfs.h>
>  #include <linux/iio/trigger_consumer.h>
>  #include <linux/iio/buffer.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/trigger_consumer.h>
>  #include <linux/iio/triggered_buffer.h>
>  #include <linux/iio/events.h>
>  #include <linux/delay.h>
> @@ -555,18 +557,24 @@ static irqreturn_t mma8452_interrupt(int irq, void *p)
>  {
>  	struct iio_dev *indio_dev = p;
>  	struct mma8452_data *data = iio_priv(indio_dev);
> +	int ret = IRQ_NONE;
>  	int src;
>
>  	src = i2c_smbus_read_byte_data(data->client, MMA8452_INT_SRC);
>  	if (src < 0)
>  		return IRQ_NONE;
>
> +	if (src & MMA8452_INT_DRDY) {
> +		iio_trigger_poll_chained(indio_dev->trig, iio_get_time_ns());
> +		ret = IRQ_HANDLED;
> +	}
> +
>  	if (src & MMA8452_INT_TRANS) {
>  		mma8452_transient_interrupt(indio_dev);
> -		return IRQ_HANDLED;
> +		ret = IRQ_HANDLED;
>  	}
>
> -	return IRQ_NONE;
Leave the returns as they were and just return from the new if statement...
It's neater and there is no reason to do a single point of exit if
there is no cleaning up to do.
> +	return ret;
>  }
>
>  static irqreturn_t mma8452_trigger_handler(int irq, void *p)
> @@ -699,6 +707,67 @@ static const struct iio_info mma8452_info = {
>
>  static const unsigned long mma8452_scan_masks[] = {0x7, 0};
>
> +static int mma8452_data_rdy_trigger_set_state(struct iio_trigger *trig,
> +		bool state)
> +{
> +	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
> +	struct mma8452_data *data = iio_priv(indio_dev);
> +	int reg;
> +
> +	reg = i2c_smbus_read_byte_data(data->client, MMA8452_CTRL_REG4);
> +	if (reg < 0)
> +		return reg;
> +
> +	if (state)
> +		reg |= MMA8452_INT_DRDY;
> +	else
> +		reg &= ~MMA8452_INT_DRDY;
> +
> +	return mma8452_change_config(data, MMA8452_CTRL_REG4, reg);
> +}
> +
> +static const struct iio_trigger_ops mma8452_trigger_ops = {
> +	.set_trigger_state = mma8452_data_rdy_trigger_set_state,
> +	.owner = THIS_MODULE,
> +};
> +
> +static int mma8452_trigger_setup(struct iio_dev *indio_dev)
> +{
> +	struct mma8452_data *data = iio_priv(indio_dev);
> +	struct iio_trigger *trig;
> +	int ret;
> +
> +	trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
> +						indio_dev->id);
> +	if (!trig)
> +		return -ENOMEM;
> +
> +	trig->dev.parent = &data->client->dev;
> +	trig->ops = &mma8452_trigger_ops;
> +	iio_trigger_set_drvdata(trig, indio_dev);
> +
> +	ret = iio_trigger_register(trig);
> +	if (ret)
> +		goto err_trigger_free;
> +
> +	indio_dev->trig = trig;
> +
> +	return 0;
> +
> +err_trigger_free:
> +	iio_trigger_free(trig);
> +
> +	return ret;
> +}
> +
> +static void mma8452_trigger_cleanup(struct iio_dev *indio_dev)
> +{
> +	if (indio_dev->trig) {
> +		iio_trigger_unregister(indio_dev->trig);
Probably no reason not use devm_iio_trigger_alloc and avoid the frees.
Doesn't save much, but someone else will only propose a patch 10 minutes
after this goes in if you don't do it...
> +		iio_trigger_free(indio_dev->trig);
> +	}
> +}
> +
>  static int mma8452_reset(struct i2c_client *client)
>  {
>  	int i;
> @@ -772,7 +841,8 @@ static int mma8452_probe(struct i2c_client *client,
>  		return ret;
>
>  	if (client->irq) {
> -		int supported_interrupts = MMA8452_INT_TRANS;
> +		int supported_interrupts = MMA8452_INT_DRDY | MMA8452_INT_TRANS;
> +		int enabled_interrupts = MMA8452_INT_TRANS;
Note again, I'm very much against coming up with any events enabled....
It's not what people expect so all sorts of messy things could occur.
>
>  		/* Assume wired to INT1 pin */
>  		ret = i2c_smbus_write_byte_data(client,
> @@ -783,7 +853,11 @@ static int mma8452_probe(struct i2c_client *client,
>
>  		ret = i2c_smbus_write_byte_data(client,
>  						MMA8452_CTRL_REG4,
> -						supported_interrupts);
> +						enabled_interrupts);
> +		if (ret < 0)
> +			return ret;
> +
> +		ret = mma8452_trigger_setup(indio_dev);
>  		if (ret < 0)
>  			return ret;
>  	}
> @@ -793,12 +867,12 @@ static int mma8452_probe(struct i2c_client *client,
>  	ret = i2c_smbus_write_byte_data(client, MMA8452_CTRL_REG1,
>  		data->ctrl_reg1);
>  	if (ret < 0)
> -		return ret;
> +		goto trigger_cleanup;
>
>  	ret = iio_triggered_buffer_setup(indio_dev, NULL,
>  		mma8452_trigger_handler, NULL);
>  	if (ret < 0)
> -		return ret;
> +		goto trigger_cleanup;
>
>  	ret = iio_device_register(indio_dev);
>  	if (ret < 0)
> @@ -820,6 +894,10 @@ device_cleanup:
>
>  buffer_cleanup:
>  	iio_triggered_buffer_cleanup(indio_dev);
> +
> +trigger_cleanup:
> +	mma8452_trigger_cleanup(indio_dev);
> +
>  	return ret;
>  }
>
> @@ -829,6 +907,7 @@ static int mma8452_remove(struct i2c_client *client)
>
>  	iio_device_unregister(indio_dev);
>  	iio_triggered_buffer_cleanup(indio_dev);
> +	mma8452_trigger_cleanup(indio_dev);
>  	mma8452_standby(iio_priv(indio_dev));
>
>  	return 0;
>
> --
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