Re: [PATCH v3 1/2] iio: acpi_als: Add timestamp channel

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 10 Dec 2020 14:15:40 -0800
Gwendal Grignou <gwendal@chromium.org> wrote:

> Add timestamp channel in list of channel, to allow retrieving timestamps
> when events are produced.

Giving IIO naming, events would be thresholds rather than buffered flow
that you are talking about here.

Not hugely important though.

> 
> Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
> ---
>  Changes in v3: none.
> 
>  drivers/iio/light/acpi-als.c | 11 +++++------
>  1 file changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/iio/light/acpi-als.c b/drivers/iio/light/acpi-als.c
> index 1eafd0b24e182..ff0ecec65fae4 100644
> --- a/drivers/iio/light/acpi-als.c
> +++ b/drivers/iio/light/acpi-als.c
> @@ -45,24 +45,23 @@ static const struct iio_chan_spec acpi_als_channels[] = {
>  		.info_mask_separate	= BIT(IIO_CHAN_INFO_RAW) |
>  					  BIT(IIO_CHAN_INFO_PROCESSED),
>  	},
> +	IIO_CHAN_SOFT_TIMESTAMP(1),
>  };
>  
>  /*
>   * The event buffer contains timestamp and all the data from
>   * the ACPI0008 block. There are multiple, but so far we only
> - * support _ALI (illuminance). Once someone adds new channels
> - * to acpi_als_channels[], the evt_buffer below will grow
> - * automatically.
> + * support _ALI (illuminance):
> + * One channel, paddind and timestamp.

padding

>   */
> -#define ACPI_ALS_EVT_NR_SOURCES		ARRAY_SIZE(acpi_als_channels)
>  #define ACPI_ALS_EVT_BUFFER_SIZE		\
> -	(sizeof(s64) + (ACPI_ALS_EVT_NR_SOURCES * sizeof(s32)))
> +	(sizeof(s32) + sizeof(s32) + sizeof(s64))
>  
>  struct acpi_als {
>  	struct acpi_device	*device;
>  	struct mutex		lock;
>  
> -	s32			evt_buffer[ACPI_ALS_EVT_BUFFER_SIZE];
> +	s32 evt_buffer[ACPI_ALS_EVT_BUFFER_SIZE / sizeof(s32)]  __aligned(8);
>  };
>  
>  /*