Re: [PATCH 06/19] iio: accel: stk8312: Fix buffer alignment in iio_push_to_buffers_with_timestamp()

[Jonathan Cameron <jic23@kernel.org>]

On Sat,  1 May 2021 18:01:08 +0100
Jonathan Cameron <jic23@kernel.org> wrote:

> From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 
> To make code more readable, use a structure to express the channel
> layout and ensure the timestamp is 8 byte aligned.
> 
> Found during an audit of all calls of this function.
> 
> Fixes: 95c12bba51c3 ("iio: accel: Add buffer mode for Sensortek STK8312")
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Also missing the __aligned(8) for the timestamp.  Added it.

thanks,

Jonathan

> ---
>  drivers/iio/accel/stk8312.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iio/accel/stk8312.c b/drivers/iio/accel/stk8312.c
> index 157d8faefb9e..c8b6915a757c 100644
> --- a/drivers/iio/accel/stk8312.c
> +++ b/drivers/iio/accel/stk8312.c
> @@ -103,7 +103,11 @@ struct stk8312_data {
>  	u8 mode;
>  	struct iio_trigger *dready_trig;
>  	bool dready_trigger_on;
> -	s8 buffer[16]; /* 3x8-bit channels + 5x8 padding + 64-bit timestamp */
> +	/* Ensure timestamp is naturally aligned */
> +	struct {
> +		s8 chans[3];
> +		s64 timestamp;
> +	} scan;
>  };
>  
>  static IIO_CONST_ATTR(in_accel_scale_available, STK8312_SCALE_AVAIL);
> @@ -438,7 +442,7 @@ static irqreturn_t stk8312_trigger_handler(int irq, void *p)
>  		ret = i2c_smbus_read_i2c_block_data(data->client,
>  						    STK8312_REG_XOUT,
>  						    STK8312_ALL_CHANNEL_SIZE,
> -						    data->buffer);
> +						    data->scan.chans);
>  		if (ret < STK8312_ALL_CHANNEL_SIZE) {
>  			dev_err(&data->client->dev, "register read failed\n");
>  			mutex_unlock(&data->lock);
> @@ -452,12 +456,12 @@ static irqreturn_t stk8312_trigger_handler(int irq, void *p)
>  				mutex_unlock(&data->lock);
>  				goto err;
>  			}
> -			data->buffer[i++] = ret;
> +			data->scan.chans[i++] = ret;
>  		}
>  	}
>  	mutex_unlock(&data->lock);
>  
> -	iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
> +	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
>  					   pf->timestamp);
>  err:
>  	iio_trigger_notify_done(indio_dev->trig);